CN101955788A

CN101955788A - Fischer-Tropsch synthesis method and system

Info

Publication number: CN101955788A
Application number: CN2010105143709A
Authority: CN
Inventors: 石玉林; 吴秀章; 公磊; 林泉; 吕毅军; 卜亿峰; 王洪学
Original assignee: China Shenhua Coal to Liquid Chemical Co Ltd; Shenhua Group Corp Ltd
Current assignee: China Shenhua Coal to Liquid Chemical Co Ltd; Shenhua Group Corp Ltd
Priority date: 2010-07-09
Filing date: 2010-10-20
Publication date: 2011-01-26
Anticipated expiration: 2030-10-20
Also published as: CN101892063A; US20130116348A1; WO2012003806A1; RU2562770C2; CN101955788B; RU2013102957A

Abstract

The invention relates to a Fischer-Tropsch synthesis method and a system. The method comprises the following steps: a) making CO and H2-containing raw gas enter the first section of a Fischer-Tropsch synthesis reactor to perform Fischer-Tropsch synthesis reaction and obtain the product at the first section of Fischer-Tropsch synthesis reaction; b) separating the product at the first section of Fischer-Tropsch synthesis reaction so as to separate water and unconverted tail gas and obtain a hydrocarbon product and unconverted tail gas of the first section of Fischer-Tropsch synthesis reaction; c) making the unconverted tail gas obtained in the step b) enter the second section of the Fischer-Tropsch synthesis reactor to perform Fischer-Tropsch synthesis reaction and obtain the product at the second section of Fischer-Tropsch synthesis reaction; and d) separating the product at the second section of Fischer-Tropsch synthesis reaction so as to separate water and unconverted tail gas and obtain a hydrocarbon product and unconverted tail gas of the second section of Fischer-Tropsch synthesis reaction, wherein one part of the unconverted tail gas of the second section of Fischer-Tropsch synthesis reaction is returned to the second section of the Fischer-Tropsch synthesis reactor for cyclic reaction. The method and system of the invention simplify the process and are suitable for large-scale industrial production.

Description

A kind of Fischer-Tropsch synthesis method and system

Technical field

The present invention relates to a kind of Fischer-Tropsch synthesis method (Fischer-Tropsch Synthesis) and system, relate in particular to a kind of two stage Fischer-Tropsch synthesis method and system.

Background technology

Along with oil price is constantly soaring in recent years, people more and more pay attention to the technology that Development and Production substitutes oil product, by coal, Sweet natural gas or other material production synthetic gas, again according to the requirement of fischer-tropsch synthetic catalyst to synthetic gas, by water-gas shift and purified synthesis gas technology synthetic gas is handled, to handle the back synthetic gas is that raw material is by the synthetic hydro carbons of producing of Fischer-Tropsch, while by-product oxygenatedchemicals, adopt sophisticated Petroleum Processing Technology to process then, produce high-quality eco-friendly oil product, its core is the Fischer-Tropsch synthetic technology.As seen develop new Fischer-Tropsch synthesis process, have very important significance developing alternative oil manufacture technology.

(Gao Jinsheng, Zhang Dexiang write " gelatin liquefaction technology ", Chemical Industry Press, March in 2005 the 1st edition) introduced the sophisticated Fischer-Tropsch synthesis process of Sasol company, its technical process is single hop technology substantially, the Sasol syrup state bed Fischer Tropsch synthesis technique that the Arge technology that adopts fixed bed, the Kellogg technology that the employing fluidized-bed is arranged and employing slurry attitude bed are arranged according to the difference of type of reactor, the tail gas of Arge technology is as the raw material of Kellogg technology in Sasol I factory, and not seeing has the two-part technical process of adopting same reactor.

Paste state bed reactor is a three-phase bubble column, operates under moderate temperature, by unstripped gas (gas phase) bubbling in fused Fischer-Tropsch synthetic wax (liquid phase) and granules of catalyst (solid phase).Raw material of synthetic gas through preheating enters reactor from reactor bottom, diffuses in the slurry of being made up of liquid wax that generates and granules of catalyst.Fischer-Tropsch synthesis constantly takes place in synthetic gas in the process that bubble rises, and generates more Fischer-Tropsch synthetic wax.The heat that reaction produces is produced steam by built-in spiral coil cooling tube and is taken out.Wax product is extracted reactor out by obtaining separating in the built-in strainer of reactor slurry attitude bed reaction zone, perhaps employing obtains by the method for external equipment for separating liquid from solid with Fischer-Tropsch synthetic wax and catalyst solid particle separation after extracting slurries out.From reactor top tail gas discharged cooling recyclable light component in back and water.The product a refining unit of the hydrocarbon product fed downstream that obtains, water then are sent to retrieving arrangement and handle.

The paste state bed reactor reactant mixes, has the good heat transfer performance, helps the control of temperature of reaction and shifting out of reaction heat, but isothermal operation, thus available higher average operation temperature and obtain higher speed of reaction; Control is simple, and running cost is low; By clocklike replacing catalyzer, the average catalyst life-span is easy to control; Be easier to the selectivity of control process, improve the quality of thick product.Therefore, it is obvious that syrup state bed Fischer Tropsch synthesizes under based on the situation of producing synthetic wax and diesel oil superiority, becomes Fischer-Tropsch synthetic technology development trend.

The design of paste state bed reactor has its uniqueness, in order to keep the slurry bed characteristic, at first be that catalyzer is manufactured tiny particle so that can be suspended in the liquid phase region, it two is in the interval operation of specific temperature of reaction so that the Fischer-Tropsch synthetic wax that reaction generates exists with liquid form and provides outside the slurry attitude condition, in addition, still need and to operate with certain gas flow rate (empty tower gas velocity), both avoided causing the granules of catalyst deposition, and avoided gas flow rate too high and granules of catalyst is carried out reactor again because of gas flow rate is little.Therefore, when needs increase Fischer-Tropsch synthesizer throughput, when promptly increasing Fischer-Tropsch synthesis material gas flow, need to improve reactor diameter usually to keep the empty tower gas velocity that needs.

But, when improving device, needs produce the Fischer-Tropsch synthesis oil ability when reaching more than 500,000 tons/year scale, because restrictions such as reactor manufacturing process, transport condition, the diameter maximum of reactor only can reach about 10 meters under the level at present, therefore needs the paste state bed reactor more than at least two to process.The megaton Fischer-Tropsch synthesizer of suitability for industrialized production is designed to the complete conventional separate unit paste state bed reactor Fischer-Tropsch synthesis process device parallel operation of two covers at present.Every reactor head product all is provided with oil-water-gas separating system, and most of tail gas loops back reactor separately, with the total efficiency of carbon conversion that need to obtain, the emptying of small part tail gas.

Chinese patent publication number CN1611565 (application number CN200310108146.X) discloses a kind of technology of producing liquid fuel with synthetic gas, and this processing method comprises Fischer-Tropsch synthesis unit, C ₃-C ₅Reclaim unit, three parts of refinery unit.Wherein the Fischer-Tropsch synthesis unit is divided into two-stage, and product is paraffin and condensation product; Two-stage Fischer-Tropsch synthesizer carries out the circulation of part tail gas respectively; The residual exhaust of first step Fischer-Tropsch synthetic gas enters second stage Fischer-Tropsch synthesizer as unstripped gas; The residual exhaust of second stage Fischer-Tropsch synthesizer enters into C ₃-C ₅Reclaim the unit.C ₃-C ₅Reclaiming the unit is by degree of depth refrigerative method, reclaims the C of the overwhelming majority in the tail gas ₃Above component, the paraffin and the condensation product of these components and the production of two-stage Fischer-Tropsch synthesis unit enter the production that refinery unit is carried out liquid fuel together.This process using dual stage apparatus Fischer-Tropsch is synthetic, can reduce CH by reducing the method for single-stage CO transformation efficiency ₄Productive rate.But the part tail gas of this technology first step Fischer-Tropsch synthesizer circulates, and has increased investment of recycle compressor system and process cost, has reduced the economy of whole technology.In addition, first step Fischer-Tropsch synthesizer has adopted the circulation of part tail gas, has reduced the load of reactor processing fresh synthesis gas raw material, has reduced oily yield.

Chinese patent publication number CN1948438 (application number CN200610140020.4) has introduced a kind of Fischer-Tropsch synthesis method, may further comprise the steps: a) make raw material of synthetic gas enter first section Fischer-Tropsch synthesis device, carry out Fischer-Tropsch synthesis under the effect of catalyzer; B) separate first section Fischer-Tropsch synthesis product, part tail gas returns first section Fischer-Tropsch synthesis device circulating reaction, is synthetic gas with the C1～C4 hydrocarbon conversion that contains in all the other tail gas then; C) will mix from the recycled offgas of the tail gas after the conversion of step b), enter second section Fischer-Tropsch synthesis device, under the effect of catalyzer, carry out Fischer-Tropsch synthesis with second section Fischer-Tropsch synthesis; D) separate second section Fischer-Tropsch synthesis product, most of tail gas returns second section Fischer-Tropsch synthesis device circulating reaction, discharges remaining tail gas.This method has adopted the gas circulation flow process at first section, is provided with gas circulating compressor, has reduced the ability of reactor processing fresh synthesis gas, and tail gas need adopt the natural gas auto-thermal oxidation process for preparing synthetic gas with C when entering second section ₁～C ₄Lighter hydrocarbons are converted into synthetic gas, have increased equipment cost.

Chinese patent publication number CN100575457C (patent No. ZL200610140019.1) has introduced a kind of Fischer-Tropsch synthesis method, may further comprise the steps: (1) makes the producing synthesis gas from coal raw material enter first step Fischer-Tropsch synthesis device, contact with ferrum-based catalyst, and under the Fischer-Tropsch synthesis condition, react; (2) separate the first order reaction product, the remaining tail gas in reaction back removes CO ₂After, enter C1-C4 hydrocarbon conversion device to produce CO and H ₂, make the tail gas after the conversion enter second stage Fischer-Tropsch synthesis device then, contact with cobalt-base catalyst, and under the Fischer-Tropsch synthesis condition, react; (3) separate the second order reaction product, discharge section tail gas, remaining tail gas return first step Fischer-Tropsch synthesis device and recycle.This method first step reactor has adopted slurry attitude bed, and it is the tail gas circulation gas of second stage reaction that the part feed gas is arranged, and cobalt-base catalyst is adopted in second stage reaction, though space-time yield is higher, but because reactor is a fixed bed, the difficult control of reaction heat-obtaining, and fixed-bed process is difficult to large-scale application.

Summary of the invention

The object of the present invention is to provide a kind of mould Fischer-Tropsch synthesis method and system, especially two stage Fischer-Tropsch synthesis method and system.

One aspect of the present invention relates to a kind of Fischer-Tropsch synthesis method, may further comprise the steps:

A) first section Fischer-Tropsch synthesis

Make and contain CO and H ₂Unstripped gas enter first section Fischer-Tropsch synthesis device, under the effect of catalyzer, carry out Fischer-Tropsch synthesis, obtain first section Fischer-Tropsch synthesis product;

B) separation of first section Fischer-Tropsch synthesis product

First section Fischer-Tropsch synthesis product separated, water is separated with unconverted tail gas, obtain the unconverted tail gas of hydrocarbon product, first section Fischer-Tropsch synthesis;

C) second section Fischer-Tropsch synthesis

The unconverted tail gas that obtains in the step b) is entered second section Fischer-Tropsch synthesis device, under the effect of catalyzer, carry out Fischer-Tropsch synthesis, obtain second section Fischer-Tropsch synthesis product;

D) separation of second section Fischer-Tropsch synthesis product

Second section Fischer-Tropsch synthesis product separated, water is separated with unconverted tail gas, obtain the unconverted tail gas of hydrocarbon product, second section Fischer-Tropsch synthesis, the part of the unconverted tail gas of second section Fischer-Tropsch synthesis is returned second section Fischer-Tropsch synthesis device circulating reaction.

The present invention relate to the Fischer-Tropsch synthesis system on the other hand, comprising:

A) first section Fischer-Tropsch synthesis device wherein accommodates fischer-tropsch synthetic catalyst, and first section Fischer-Tropsch synthesis device has at least:

First section reactor inlet is positioned at the bottom of first section Fischer-Tropsch synthesis device;

First section reactor head exports, and is positioned at the top of first section Fischer-Tropsch synthesis device;

First section Fischer-Tropsch synthetic wax or slurries outlet are positioned at the slurry attitude bed district of first section Fischer-Tropsch synthesis device;

B) first section separation system is used for the top product from first section reactor head outlet is separated, and water is separated with unconverted tail gas, obtains the unconverted tail gas of hydrocarbon product, first section Fischer-Tropsch synthesis; First section separation system has:

First section separation system inlet links to each other with first section reactor head outlet;

A plurality of first section separation system outlet comprise:

The outlet of first section hydrocarbon product and

First section unconverted tail gas outlet;

C) second section Fischer-Tropsch synthesis device wherein accommodates fischer-tropsch synthetic catalyst, and second section Fischer-Tropsch synthesis device has at least:

Second section reactor inlet is positioned at the bottom of second section Fischer-Tropsch synthesis device, and links to each other with first section unconverted tail gas outlet;

Second section reactor head exports, and is positioned at the top of second section Fischer-Tropsch synthesis device;

Second section Fischer-Tropsch synthetic wax or slurries outlet are positioned at the slurry attitude bed district of second section Fischer-Tropsch synthesis device;

D) second section separation system is used for the top product from second section reactor head outlet is separated, and water is separated with unconverted tail gas, obtains the unconverted tail gas of hydrocarbon product, second section Fischer-Tropsch synthesis, and second section separation system has:

Second section separation system inlet links to each other with second section reactor head outlet;

A plurality of second section separation system outlet comprise:

The outlet of second section hydrocarbon product and

Second section unconverted tail gas outlet.

Method and system of the present invention has overcome the facility investment that exists when conventional Fischer-Tropsch synthesis method is produced liquid product and process cost height, space-time yield is low, the CO utilization ratio is low shortcoming, has simplified technical process, and has been suitable for large-scale industrial production.

Description of drawings

Fig. 1 is the schema of the extensive Fischer-Tropsch synthesis process of two-part of the present invention.

Embodiment

The present invention is dependent on the understanding of Fischer-Tropsch synthesis (especially Fe-series catalyst Fischer-Tropsch synthesis) basic characteristics is carried out.

Main reaction has two classes during the Fe-series catalyst Fischer-Tropsch synthesis:

CO+H ₂→ HC (hydrocarbon)+H ₂O (1)

Wherein second class reaction (2) is water gas shift reaction (WGS reaction), and it is a reversible reaction, and the CO that it took place conversion accounts for 15～35% of total carbon conversion.

Obviously, improve the production capacity of Fischer-Tropsch synthesis speed, increase device Fischer-Tropsch synthesis oil, and the method for raising CO utilization ratio is to improve the effective synthetic gas (CO+H of reactor inlet ₂) flow (keeping under the specific empty tower gas velocity and can representing) with the dividing potential drop of effective synthetic gas, and reduce WGS forward reaction speed.Can find out that from the WGS reaction characteristics reduce WGS forward reaction speed, the effective means that improves the utilization ratio of CO has two: the H in a. minimizing system ₂The O dividing potential drop; B. CO in the raising system ₂Dividing potential drop.

On the other hand, owing to there is second class WGS reaction on the Fe-series catalyst, therefore the water partial pressure in the reduction system helps reducing WGS forward reaction speed, has relatively increased the CO reactant concn that first kind Fischer-Tropsch synthesis is converted into hydrocarbon, helps improving Fischer-Tropsch synthesis speed.

The inventor finds, when reactor carries out the segmentation setting, when carrying out gas-phase dehydration in the middle of the section, can improve Fischer-Tropsch synthesis speed, increases device capbility.

When cobalt-base catalyst existed, though the WGS reaction takes place hardly, the existence of the water of Fischer-Tropsch synthesis production can influence Fischer-Tropsch synthesis speed equally.

Understanding and test according to the Fischer-Tropsch synthesis performance have proposed the present invention.

In the present invention, " with ... link to each other " or " being connected to ", both can be that the two directly links to each other, also can link to each other or connect across common parts or device (for example valve, pump, interchanger etc.).

In the present invention, under reconcilable situation, all embodiment of the present invention, embodiment and feature can make up mutually.

The present invention relates to a kind of Fischer-Tropsch synthesis method, may further comprise the steps:

A) first section Fischer-Tropsch synthesis

B) separation of first section Fischer-Tropsch synthesis product

C) second section Fischer-Tropsch synthesis

D) separation of second section Fischer-Tropsch synthesis product

Preferably, the unconverted tail gas of first section Fischer-Tropsch synthesis does not return first section Fischer-Tropsch synthesis device circulating reaction.

Preferably, in step a), fresh synthesis gas passes through first section Fischer-Tropsch synthesis device as the unstripped gas one way.

Preferably, control in first section Fischer-Tropsch synthesis device the CO transformation efficiency, more preferably 40%～65%, further preferred 50%～60% at 30%-70%.

Preferably, water-content is lower than 0.05% in the unstripped gas, preferably is lower than 0.01%, more preferably less than 0.005%, most preferably is lower than 0.0001% (volume ratio).

Preferably, the unconverted tail gas water-content that enters second section Fischer-Tropsch synthesis device is lower than 0.05%, preferably is lower than 0.01%, more preferably less than 0.005%, most preferably is lower than 0.0001% (volume ratio).

Preferably, preferably control in first section Fischer-Tropsch synthesis device the CO transformation efficiency, more preferably 40%～65%, further preferred 50%～60% 30%～70%.

Separating in step b) and the step d) comprises: the oil-water of Fischer-Tropsch synthesis top product-gas separates.Preferably, b) oil-water of first section Fischer-Tropsch synthesis top product-gas separates and/or d) oil-water-gas of second section Fischer-Tropsch synthesis top product separates and may further comprise the steps:

At first, adopt high pressure hot separator (being called for short " hot high score ") to carry out flash separation, obtain high pressure hot separator liquid, high pressure hot separator gas;

Then, adopt cold high pressure separator (being called for short " cold high score ") to carry out flash separation high pressure hot separator gas, obtain two-phase: cold high pressure separator liquid is the blended liquid phase product of light ends oil and water, and cold high pressure separator gas is unconverted tail gas.

Preferably, high pressure hot separator is under 120～220 ℃, preferably 140～180 ℃ of operations down.Preferably, cold high pressure separator is under 5～60 ℃, more preferably 10～50 ℃ of operations down.

Preferably, method of the present invention further comprises:

E) the high pressure hot separator liquid with first section, second section Fischer-Tropsch synthesis feeds thermal low-pressure separators (being called for short " heat is low divides "), and flash separation obtains heavy ends oil production and thermal low-pressure separators gas once more; And alternatively

F) with the blended liquid phase product of the cold high pressure separator of first section, second section Fischer-Tropsch synthesis (being called for short " cold high score ") and optionally thermal low-pressure separators gas feed cold low separator (being called for short " cold low branch "), flash separation obtains cold low separator gas, light ends oil production, water.

Thermal low-pressure separators can 60～200 ℃, preferred 70～180 ℃, more preferably 80～160 ℃, most preferably carry out under 90～140 ℃.Cold low separator (cold low branch) can carry out under 5～60 ℃, preferred 20～50 ℃.

Preferably, first section Fischer-Tropsch synthesis carries out under following reaction conditions in the step a).

Preferably, for first section Fischer-Tropsch synthesis in the step a), temperature of reaction is 200～320 ℃, is preferably 235～275 ℃, more preferably 245～265 ℃.

Preferably, for first section Fischer-Tropsch synthesis in the step a), reaction pressure is 15～50bar, is preferably 20～40bar, more preferably 25～35bar.

Preferably, for first section Fischer-Tropsch synthesis in the step a), reactor inlet gas empty tower gas velocity is 10～40cm/s, is preferably 15～35cm/s, more preferably 15～25cm/s.

Preferably, for first section Fischer-Tropsch synthesis in the step a), the volumetric flow rate of unstripped gas (reactor inlet gas) is 2000～50000Nml/g-cat./h with the ratio of catalyst quality (i.e. gas agent ratio), be preferably 5000～30000Nml/g-cat./h, more preferably 8000～20000Nml/g-cat./h.

Preferably, second section Fischer-Tropsch synthesis carries out under following reaction conditions in the step c).

Preferably, for second section Fischer-Tropsch synthesis in the step a), temperature of reaction is 200～320 ℃, is preferably 235～275 ℃, more preferably 245～265 ℃.

Preferably, for second section Fischer-Tropsch synthesis in the step a), reaction pressure is 15～50bar, is preferably 18～38bar, more preferably 25～35bar.

Preferably, for second section Fischer-Tropsch synthesis in the step a), the reactor inlet empty tower gas velocity is 10～40cm/s, is preferably 15～35cm/s, more preferably 15～25cm/s.

Preferably, for second section Fischer-Tropsch synthesis in the step a), the volume ratio of reactor inlet gas flow and catalyzer (i.e. gas agent ratio) is 2000～50000Nml/g-cat./h, is preferably 5000～30000Nml/g-cat./h, more preferably 8000～20000Nml/g-cat./h.

Preferably, for first section Fischer-Tropsch synthesis in the step a), CO and H in the unstripped gas ₂Volume ratio be 0.67～2.2, preferred 0.8～2, more preferably 1～2, most preferably 1.4～2.

Preferably, unstripped gas is synthetic gas in the step a), preferably the synthetic gas of process purification and water-gas shift.Preferably with fresh synthesis gas as unstripped gas.

Preferably, step a) and c) in employed catalyzer be Fe-series catalyst or cobalt series catalyst.Preferably, when adopting Fe-series catalyst, the H of unstripped gas ₂With the volume ratio of CO for being 1.4～1.8, preferred 1.4～1.7, more preferably 1.5～1.7, most preferably 1.5～1.6.Preferably, when adopting cobalt series catalyst, the H of unstripped gas ₂With the volume ratio of CO be 1.8～2.2, preferred 1.9～2.1, more preferably 1.95～2.05, most preferably 2.0.

Preferably, the number of first section Fischer-Tropsch synthesis device equals or more than second section Fischer-Tropsch synthesis device number, more preferably the number of first section Fischer-Tropsch synthesis device is more than second section Fischer-Tropsch synthesis device number.The number of the number of first section Fischer-Tropsch synthesis device or first section Fischer-Tropsch synthesis device is during more than 1 (that is, more than 2), and the Fischer-Tropsch synthesis device of this section is in parallel.

Preferably, first section Fischer-Tropsch synthesis device and second section Fischer-Tropsch synthesis device are paste state bed reactor.Preferred first section Fischer-Tropsch synthesis device is one or a plurality of paste state bed reactors in parallel, and second section Fischer-Tropsch synthesis device is a paste state bed reactor.The Fischer-Tropsch synthesis device can also be fixed bed, fixed fluidized bed, fluidized-bed.

Preferably, the unconverted tail gas of second section Fischer-Tropsch synthesis mixes with the unconverted tail gas of whole first section Fischer-Tropsch synthesis, enters second section Fischer-Tropsch synthesis device then.The unconverted tail gas of preferred second section Fischer-Tropsch synthesis is 0.5～5 with the unconverted tail gas mixed volume ratio of first section Fischer-Tropsch synthesis, is preferably 1～3, more preferably 1.5～2.5.Preferably, before mixing, remove the CO in the unconverted tail gas of second section Fischer-Tropsch synthesis ₂For example, remove CO ₂Adopt hot salt of wormwood to take off CO ₂Method or WATER-WASHING METHOD are carried out.

Preferably, in the step b), the reactor head product enters high pressure hot separator (for example, under 120～220 ℃, being preferably 140～180 ℃), carries out flash separation and goes out gas phase and heavy oil phase.Gaseous stream enters cold high pressure separator (for example, under 5～60 ℃, being preferably 10～50 ℃), and flash separation once more obtains the blended liquid phase product of gas, light ends oil and synthetic water.

Preferably, in the step d), the reactor head product enters high pressure hot separator (for example, under 120～220 ℃, being preferably 140～180 ℃), carries out flash separation and obtains gas phase and heavy oil phase.Gaseous stream enters cold high pressure separator (for example, under 5～60 ℃, being preferably 10～50 ℃), and flash separation once more obtains the blended liquid phase product of gas, light ends oil and synthetic water.

The quantity discharged of tail gas is by CO+H in the tail gas ₂Content decision, to guarantee CO+H in the tail gas ₂Content be not less than 40%, CO+H in tail gas ₂Content be higher than 50%, reduce quantity discharged; CO+H in tail gas ₂Content be lower than 40%, then increase quantity discharged.

The present invention relates to the Fischer-Tropsch synthesis system on the other hand, comprising:

A) first section Fischer-Tropsch synthesis device wherein accommodates fischer-tropsch synthetic catalyst, and first section Fischer-Tropsch synthesis utensil has:

B) first section separation system is used for the top product from first section reactor head outlet is separated, and water is separated with unconverted tail gas, obtains the unconverted tail gas of hydrocarbon product, first section Fischer-Tropsch synthesis, and first section separation system has:

A plurality of first section separation system outlet comprise:

The outlet of first section hydrocarbon product and

First section unconverted tail gas outlet;

C) second section Fischer-Tropsch synthesis device wherein accommodates fischer-tropsch synthetic catalyst, and second section Fischer-Tropsch synthesis utensil has:

Second section reactor inlet is positioned at the bottom of second section Fischer-Tropsch synthesis device,

And link to each other with first section unconverted tail gas outlet;

Second section reactor head exports, and is positioned at the top of second section Fischer-Tropsch synthesis device 102;

A plurality of second section separation system outlet comprise:

The outlet of second section hydrocarbon product and

Second section unconverted tail gas outlet.

Preferably, first section unconverted tail gas outlet do not connect first section reactor inlet.

Preferably, B) first section separation system and/or D) second section separation system comprise oil-water-air separation.

Preferably, B) first section separation system and/or D) oil-water-gas separating system of second section separation system comprises:

High pressure hot separator has:

The high pressure hot separator inlet links to each other with first section separation system inlet or second section separation system inlet,

The high pressure hot separator liquid exit and

The high pressure hot separator pneumatic outlet;

Cold high pressure separator has:

The cold high pressure separator inlet links to each other with the high pressure hot separator pneumatic outlet,

The cold high pressure separator liquid exit and

The cold high pressure separator pneumatic outlet.

Preferably, Fischer-Tropsch synthesis system of the present invention further comprises:

Thermal low-pressure separators has:

The thermal low-pressure separators inlet links to each other with the high pressure hot separator liquid exit of first section separation system and/or second section separation system,

The thermal low-pressure separators pneumatic outlet,

The thermal low-pressure separators liquid exit;

Alternatively, the cold low separator has:

The cold low separator inlet is connected to the outlet of thermal low-pressure separators liquid exit and/or cold high pressure separator product liquid,

The outlet of cold low separator gas,

The light ends oil export,

The outlet of Fischer-Tropsch synthetic water.

Preferably, Fischer-Tropsch synthesis system of the present invention is further taken off CO ₂CO takes off in system ₂System has:

Take off CO ₂The colvent inlet,

Take off CO ₂Solvent outlet,

Take off CO ₂The system gas inlet links to each other with the cold high pressure separator pneumatic outlet,

Take off CO ₂The system gas outlet links to each other with second section reactor inlet.

Preferably, one of first section Fischer-Tropsch synthesis device and second section Fischer-Tropsch synthesis device or a plurality of paste state bed reactors in parallel; Preferably, first section Fischer-Tropsch synthesis device is one or a plurality of paste state bed reactors in parallel, and second section Fischer-Tropsch synthesis device is a paste state bed reactor.

Preferably, the number of first section Fischer-Tropsch synthesis device is preferably greater than the number of second section Fischer-Tropsch synthesis device more than or equal to the number of second section Fischer-Tropsch synthesis device.

Preferably, Fischer-Tropsch synthesis system of the present invention further comprises: wax filter is arranged on the inside or the outside of first section Fischer-Tropsch synthesis device and second section Fischer-Tropsch synthesis device.

Preferably, Fischer-Tropsch synthesis system of the present invention further comprises: the outlet of Fischer-Tropsch synthetic wax is arranged on first section Fischer-Tropsch synthesis device and slurry attitude district, second section Fischer-Tropsch synthesis device middle part.

Preferred method and system of the present invention is two stage Fischer-Tropsch synthesis method and system.

Simply being described as of technology of the present invention, during megaton heavy industrialization device, because of it needs two above reactors, fresh synthesis material gas is that one way is passed through first section Fischer-Tropsch synthesis device, first section Fischer-Tropsch synthesis device top product separates through oil-water-gas, the unconverted tail gas that obtains enters second section Fischer-Tropsch synthesis device, second section Fischer-Tropsch synthesis device top exit product is again after oil-water-gas separates, most of tail gas loops back second section Fischer-Tropsch synthesis device, with the CO total conversion rate that obtains to require.This process unit height is integrated, the liquid product that the high pressure hot separator of two-stage reaction obtains all enters same thermal low-pressure separators to carry out flash separation once more and obtains heavy distillate, and the cold high pressure separator product liquid light ends of two-stage reaction oil all flow into same cold low separator with the synthetic water mixture and separates, and obtains the oily and Fischer-Tropsch synthetic water product of light ends.

A kind of preferred embodiment in, the extensive Fischer-Tropsch synthesis method of two-part provided by the invention may further comprise the steps:

A) make fresh synthesis gas unstripped gas enter first section Fischer-Tropsch synthesis device, under the effect of catalyzer, carry out Fischer-Tropsch synthesis;

B) first section Fischer-Tropsch synthesis device top product adopts high pressure hot separator and cold high pressure separator flash separation to obtain first section Fischer-Tropsch synthesis product such as the blended liquid phase of heavy oil phase, lightweight oil and synthetic water, unconverted tail gas in succession;

C) gas with the synthetic cold high pressure separator of first section Fischer-Tropsch mixes with the recycled offgas of second section Fischer-Tropsch synthesis, enters second section Fischer-Tropsch synthesis device, carries out Fischer-Tropsch synthesis under the effect of catalyzer;

D) adopt second section Fischer-Tropsch synthesis product of high pressure hot separator and cold high pressure separator flash separation in succession, obtain blended liquid phase, tail gas of heavy oil phase, lightweight oil and synthetic water etc., most of tail gas returns second section Fischer-Tropsch synthesis device circulating reaction, discharges remaining tail gas;

E) the synthetic high pressure hot separator liquid of first section, second section Fischer-Tropsch is fed a thermal low-pressure separators simultaneously, flash separation obtains the heavy ends oil production once more;

F) the blended liquid phase product with the synthetic cold high pressure separator of first section, second section Fischer-Tropsch feeds a cold low separator simultaneously, and flash separation obtains light ends oil, synthetic water product once more.

Further describe two stage Fischer-Tropsch synthesis method of the present invention below, but therefore the present invention is not subjected to any restriction.

Fresh synthesis gas in the above-mentioned Fischer-Tropsch synthesis method in the step a) can be produced by coal, Sweet natural gas or organism, but must remove the material to the toxic effect of fischer-tropsch synthetic catalyst such as its contained sulphur through purifying." gelatin liquefaction technology " (Chemical Industry Press, author: Gao Jinsheng, Zhang Dexiang, publication time: in March, 2005) described the correlation technique for preparing synthetic gas, purified synthesis gas and conversion in detail.H in the fresh synthesis gas ₂With the volume ratio of CO be 0.67～2.2, preferred 0.8～2, more preferably 1～2, most preferably 1.4～2.

First section Fischer-Tropsch synthesis carries out under following reactant condition in the step a): temperature of reaction is 200～320 ℃, is preferably 235～275 ℃; Reaction pressure is 15～50bar, is preferably 20～40bar; Make reactor inlet gas empty tower gas velocity reach 10～40cm/s, be preferably 15～35cm/s; The volume ratio of fresh synthesis gas raw material and catalyzer is 2000～50000, is preferably 5000～30000.The invention belongs to the low temperature Fischer-Tropsch synthesis.

In the step b), the reactor head product enters high pressure hot separator, under 120～220 ℃, is preferably 140～180 ℃, carries out flash separation and goes out gas phase (high pressure hot separator gas) and heavy oil phase (high pressure hot separator liquid).Gaseous stream enters cold high pressure separator, under 5～60 ℃, is preferably 10～50 ℃, and flash separation once more obtains the blended liquid phase product (cold high pressure separator liquid) of gas, light ends oil and synthetic water.

In the step c), the recycled offgas of second section Fischer-Tropsch synthesis with from first section Fischer-Tropsch of step b) is synthetic after transforming cold high pressure separator gas with volume ratio (recycle ratio) with 0.5～5, be preferably 1～3 and mix, enter second section Fischer-Tropsch synthesis device.Second section Fischer-Tropsch synthesis carries out under following reaction conditions: temperature of reaction is 200～320 ℃, is preferably 235～275 ℃; Reaction pressure is 15～50bar, is preferably 18～38bar; The reactor inlet empty tower gas velocity is 10～40cm/s, is preferably 15～35cm/s; The volume ratio of reactor inlet gas flow and catalyzer is 2000～50000, is preferably 5000～30000.

In the step d), the reactor head product enters high pressure hot separator, under 120～220 ℃, is preferably 140～180 ℃, carries out flash separation and obtains gas phase (high pressure hot separator gas) and heavy oil phase (high pressure hot separator liquid).Gaseous stream enters cold high pressure separator, under 5～60 ℃, is preferably 10～50 ℃, and flash separation once more obtains cold high pressure separator gas, cold high pressure separator liquid (the blended liquid phase product of light ends oil and synthetic water).Cold high pressure separator gas major part loops back reactor, and part is as exhaust emissions.The quantity discharged of tail gas is looked CO+H in the gas ₂Content and decide common CO+H ₂Content be not less than 40%, be preferably and be not less than 50%.The gas of circulation Returning reactor with remove CO before the synthetic cold high pressure separator gas of first section Fischer-Tropsch mixes ₂Remove the CO in the circulation gas ₂Method can adopt the CO that removes commonly used ₂Processing method, for example, hot salt of wormwood takes off CO ₂Method or WATER-WASHING METHOD.Hot salt of wormwood takes off CO ₂Method device commonly used is that hot salt of wormwood takes off CO ₂Adsorption tower, the saleratus of generation removes CO at regenerator column ₂, the solution of potassium carbonate that obtains returns adsorption tower again.WATER-WASHING METHOD only need be established water washing tank and be got final product.

The severity of first section Fischer-Tropsch synthesis process condition of this technology controlling and process, make the synthetic CO transformation efficiency of the section of winning Fischer-Tropsch between 35%～70%, be preferably 40%～65%, guarantee the space-time yield of catalyzer, reduce the severity of second section Fischer-Tropsch synthesis process condition, make the per pass conversion of the synthetic CO of second section Fischer-Tropsch be lower than 50%, guarantee that the productive rate of methane of whole technology is low, oil product yield height.First section and the synthetic compound back of second section Fischer-Tropsch CO total conversion rate reach more than 90%.

Step a) and c) in the Fischer-Tropsch synthesis device adopt paste state bed reactor.First section Fischer-Tropsch synthetic reactor can be one or more paste state bed reactors, only establishes a paste state bed reactor for second section.

Employed catalyzer can be iron system or cobalt system slurry attitude bed catalyst in step a) and the step c).During Fe-series catalyst, the H of fresh synthesis gas ₂With the volume ratio of CO for being preferably 1.4～1.8.During cobalt series catalyst, the H of fresh synthesis gas ₂With the volume ratio of CO for being preferably 2.0.Process natural gas base synthetic gas should adopt cobalt series catalyst, and the processing coal based synthetic gas should adopt Fe-series catalyst.

The main products (hydrocarbon product) that Fischer-Tropsch synthesizer of the present invention is produced is hydrocarbon gas (containing low-carbon alkene), light naphthar and heavy naphtha, diesel oil distillate, wax and synthetic water, especially with petroleum naphtha, diesel oil distillate and wax primary product.

The wax of producing in the Fischer-Tropsch synthesis device is discharged as product by after the strainer that is provided with in the reactor and the catalyst separating, also can by the slurries in the extraction reactor by external equipment for separating liquid from solid with obtain after granules of catalyst separates.Under the external strainer situation, separate the granules of catalyst that obtains and loop back reactor continuation participation reaction again.

Compared with prior art, two stage Fischer-Tropsch synthesis method provided by the present invention has following beneficial effect:

A. compared with the prior art two-stage process of the present invention has reduced by first section Fischer-Tropsch synthetic recycle gas compressor system, has reduced facility investment and relating operation expense.

B. at first section:

(1) total conversion rate (per pass conversion just) is moderate, and it is more reasonable that product distributes, and methane selectively is low;

(2) reactor inlet gas all is fresh synthesis gas, dry moisture-free, and first section synthetic CO total conversion rate of Fischer-Tropsch is controlled between 35%～75%, so gas phase steam dividing potential drop is lower than CO total conversion rate under the state in parallel and reaches situation more than 90% in the reactor, state when the WGS speed of reaction is lower than parallel connection, CO ₂Output descends, selectivity reduces;

(3) the effective gas dividing potential drop of reactor inlet reaches 100%, operating under the fresh synthesis gas high-speed to greatest extent under the paste state bed reactor condition, is very beneficial for Fischer-Tropsch synthesis, obtains space-time yield to greatest extent.

C. at second section:

The synthetic cold high pressure separator gas of (1) first section Fischer-Tropsch is as second section fresh synthesis gas charging, be equivalent in the multiple process separate unit reactor process and be reacted to a half and carried out the vapor condensation dehydration, the CO total conversion rate reaches 65% above reactive moieties (second half section of the reactor in the time of can regarding as multiple process separate unit reactor process) when can be regarded as second section gas phase water partial pressure in the Fischer-Tropsch synthesis device and being lower than the separate unit reactor.Therefore, help improving Fischer-Tropsch synthesis speed;

(2) because be that the stack transformation efficiency reaches more than 90% on first section Fischer-Tropsch synthesis device, per pass conversion can hang down certain operations when therefore second section Fischer-Tropsch synthesized with respect to parallel connection, and product distributes and also can improve.

The present invention passes through first section Fischer-Tropsch synthesis device by fresh synthesis gas high-speed one way, enter second section Fischer-Tropsch synthesis device after the gaseous stream condensation dehydration then, rationally regulate and control the severity of two-stage process parameter, can save a recycle gas compressor, reduce under the situation of circulation gas squeeze operation expense greatly, improve the unit space-time yield of catalyzer, reduce the productive rate of methane, realize that whole process flow is short, investment is low, operation energy consumption is little, and greater catalytic agent space-time yield, hang down the purpose of methane production.

Below in conjunction with accompanying drawing method provided by the present invention is given further instruction, but therefore the present invention is not subjected to any restriction.For outstanding process thought of the present invention, the equipment of many necessity when having omitted industrial application among the figure is as process furnace, pump, valve and interchanger etc.

As shown in Figure 1, through purifying and adjust CO and H ₂(for example, volume ratio is 0.67～2.2) fresh synthesis gas raw material 1 through interchanger 105 and 103 and the Fischer-Tropsch synthetic heat exchange after, enter first section Fischer-Tropsch synthesis device 102, Fischer-Tropsch synthesis takes place under the effect of fischer-tropsch synthetic catalyst, because Fischer-Tropsch synthesis is a strong exothermal reaction, adopt steam coils that reaction heat is taken out, the temperature of whole reactor is by the pressure-controlling of steam pockets 101, by-product water vapor 26, the wax that generates is by built-in strainer and the catalyst separating of reactor, obtain product wax 13, the mixture of the lighting end of reacted unstripped gas and part Fischer-Tropsch synthetic (promptly, top product) 2 comes out from the top of reactor 102, after interchanger 103 heat exchange, carry out gas-liquid separation with unstripped gas at high pressure hot separator 104, isolate high pressure hot separator liquid (high pressure hot separator liquid product) 11 and high pressure hot separator gas 3, high pressure hot separator gas 3 again with the unstripped gas heat exchange after, fall within the range of about 50 ℃, carry out gas-liquid separation at cold high pressure separator 106, isolate cold high pressure separator gas (unconverted tail gas) 4 and cold high pressure separator liquid (the blended liquid phase product of light ends oil and water) 6.The cold high pressure separator gas 4 of discharging from cold high pressure separator 106 tops mixes with second section recycled offgas 35, gas mixture 40 boosts through recycle gas compressor, after second section interchanger 115 and interchanger 113 and 33 heat exchange of second section Fischer-Tropsch synthesis device top product, enter second section Fischer-Tropsch synthesis device 112 and carry out the synthetic conversion of Fischer-Tropsch.The same with first section Fischer-Tropsch synthesis device 102, the temperature of reaction of second section Fischer-Tropsch synthesis device 112 is by steam pockets 111 controls, by-product water vapor 25, second section synthetic wax that generates of Fischer-Tropsch is through reactor built-in strainer and catalyst separating, obtain Fischer-Tropsch synthetic wax 43, its with obtain wax 88 after first section Fischer-Tropsch synthetic wax 13 mixes and go out device as product.Second section Fischer-Tropsch synthesis device top product 33 carries out gas-liquid separation at high pressure hot separator 114 after interchanger 113 and unstripped gas heat exchange, isolate high pressure hot separator liquid 37 and high pressure hot separator gas 34, high pressure hot separator gas 34 is again after interchanger 115 and unstripped gas heat exchange, fall within the range of about 50 ℃, carry out gas-liquid separation at cold high pressure separator 116, isolate cold high pressure separator liquid 36 and cold high pressure separator gas 10.The part of cold high pressure separator gas 10 is as tail gas 38 dischargings, and quantity discharged is by CO+H in the tail gas ₂Content decision, to guarantee CO+H in the tail gas ₂Content be not less than 40%, CO+H in tail gas ₂Content be higher than 50%, reduce quantity discharged; CO+H in tail gas ₂Content be lower than 40%, then increase quantity discharged.Remaining most of cold high pressure separator gas 27 enters decarbonization system and (promptly takes off CO ₂System) 109, gas contacts with decarbonization solvent 5 at decarbonization system 109, the most of CO in the gas ₂Enter decarbonization solvent and form alkaline residue 50 discharge decarbonization systems 109, remove CO ₂After gas as circulation gas 35 with mixes from the synthetic cold high pressure separator gas 4 of first section Fischer-Tropsch after enter recycle gas compressor 110 and boost, the mixed gas 40 after boosting returns second section Fischer-Tropsch synthesis device and enters the mouth after heat exchange.One, after two sections cold high pressure separator liquid 6 and 36 mixes, enter cold low separator 118 again with after thermal low-pressure separators gas 39 mixes, be separated into synthetic cold low separator product (the light ends oil) 58 of Fischer-Tropsch synthetic water 68, Fischer-Tropsch and the cold low separator gas 48 that contain oxygenatedchemicals and go out device; One, enters thermal low-pressure separators 117 after two sections high pressure hot separator liquid 37 and 11 mixes and be separated into thermal low-pressure separators liquid (heavy distillate) 78 and thermal low-pressure separators gas 39, heavy distillate 78 wherein goes out device as product, thermal low-pressure separators gas 39 (for example, cools to 5～50 ℃) and is mixed into cold low separator 118 with cold high pressure separator liquid 6,36 and separates after lowering the temperature.

Fischer-Tropsch synthesis is a strong exothermal reaction.For keeping Fischer-Tropsch synthesis device slurry attitude bed district under constant temperature, to operate, adopt and steam coils is set in the reactor slurry district, make the hot water that flows through in slurries and the steam coils carry out heat exchange, the mode that part hot water heat absorption back equality of temperature is vaporized is discharged reaction heat.The reaction heat of first section Fischer-Tropsch synthesis device 102 shifts out in reactor by producing the mode of paying product water vapor 26 with hot water exchange back.After slurries carry out heat exchange in the hot water 23 of steam pockets 101 and the first section Fischer-Tropsch synthesis device, the steam and the hot water mixture that form the vaporization of part hot water equality of temperature return steam pockets 101, water vapor 26 wherein discharges after by steam pockets 101 pressure-controlling, and the liquid level of steam pockets is kept by replenishing hot water 21.Similarly, the reaction heat of second section Fischer-Tropsch synthesis device 112 shifts out in reactor by the mode with hot water exchange back generation by-product water vapor 25.After slurries carry out heat exchange in the hot water 24 of steam pockets 111 and the second section Fischer-Tropsch synthesis device, the steam and the hot water mixture that form the vaporization of part hot water equality of temperature return steam pockets 111, water vapor 25 wherein discharges after by steam pockets 111 pressure-controlling, and the liquid level of steam pockets is kept by replenishing hot water 22.Two required additional hot water 20 of steam pockets provide by device is outer, and the water vapour that the process pressure-controlling gives off gathers becomes the by-product of device water vapor 28 discharge Fischer-Tropsch synthesizers, or as the thermal source utilization.

It will be appreciated by those skilled in the art that first section Fischer-Tropsch synthesis device 102 shown in Fig. 1 can be one, also a plurality of (more than 2) that can be in parallel, for example 2,3,4; Equally, second section Fischer-Tropsch synthesis device 112 can be one, also a plurality of (more than 2) that can be in parallel, for example 2,3,4.

Facility investment that method of the present invention overcomes with the synthetic gas to be existed when to be raw material by conventional Fischer-Tropsch synthesis method produce liquid product and process cost height, the shortcoming that space-time yield is low, the CO utilization ratio is low, integrated technology simultaneously, simplify technical process, and be suitable for large-scale industrial production.

Experimental section

I. effective gas dividing potential drop test enters the mouth

The contriver utilizes stirring tank slurry attitude bed reaction device and Fe-series catalyst that the different reactor Fischer-Tropsch synthesis performance that effective gas branch depresses that enters the mouth is tested, and the results are shown in Table 1.

Table 1 different reactor effective gas dividing potential drop test-results that enters the mouth

The condition numbering	Condition 1	Condition 2
			Processing condition:
Virgin gas gas agent ratio, Nml/g/h	8400	7140
			Virgin gas H ₂/ CO ratio, v/v	1.7	1.7

Virgin gas a nitrogen content, mol%	8	8
			The tail gas recycle ratio, v/v	2.33	2.75
The reactor inlet empty tower gas velocity, cm/s	Benchmark	Benchmark
			Temperature of reaction, ℃	Benchmark	Benchmark
Reaction pressure, MPa	Benchmark	Benchmark
			Test-results:
The CO total conversion rate, %	75	81
			CO ₂Selectivity, mol%	13.3	14.7
CH ₄Selectivity, mol%	3.6	4.4
			The CO per pass conversion, %	30	32
C ₅ ⁺Space-time yield, g/g-cat/h	1.0	0.9
			A nitrogen content in the circulation gas, mol%	18	21

By table 1 data as seen, keeping under identical reactor inlet empty tower gas velocity, temperature of reaction and the reaction pressure, when the agent of fresh synthesis gas gas drops to the 7140Nml/g-cat./h of condition 2 than the 8400Nml/g-cat./h from condition 1, though the CO total conversion rate can be improved, but because the effective gas of reactor inlet divides drops, space-time yield descends, and the device oil offtake reduces.Test-results shows that under identical empty tower gas velocity, the effective gas dividing potential drop that improves reactor inlet as far as possible helps improving the oil-producing capacity of device.

II. different in moisture is depressed the speed of reaction test

By feed gas conditions is CO ₂Mole fraction 0.3, CO mole fraction 0.2, H ₂Mole fraction 0.4, reaction total pressure P=2MPa experimentizes, and obtains the Fischer-Tropsch synthesis speed data that different in moisture depresses and sees Table 2:

Table 2 different in moisture is depressed the Fischer-Tropsch synthesis speed ratio

By table 2 test-results as can be known, water-content all can increase substantially Fischer-Tropsch synthesis speed in the feeding gas though different catalyzer to the susceptibility difference of water partial pressure, lowers.If the water-content in the feeding gas is removed 90% from 0.05%, to 0.005% (50ppm) (volume ratio), then Fischer-Tropsch synthesis speed can improve 11%～93%, and visual effects is very obvious.

Embodiment

Embodiment 1

Present embodiment adopts technical process shown in Figure 1, after fresh feed gas is gasification, through the H that purifies and water-gas shift obtains ₂With the volume ratio of CO be 1.54 synthetic gas, H wherein ₂Content is 60.7%, and CO content is 39.3% (volume ratio).

One, two section of present embodiment is all adopted Fe-series catalyst, and catalyzer is the SFT418-7 that the exploitation of Beijing research institute of China Shenhua Coal to Liquid and Chemical Co., Ltd., Zhejiang Twrd New Material Co., Ltd. produce.Before carrying out Fischer-Tropsch synthesis, catalyzer reduces processing in reactor.

Fischer-Tropsch synthesis carries out under the listed processing condition of table 3.

Comparative example 1 (multiple process)

For usefulness of the present invention is described better, the two cover separate unit reactor Fischer-Tropsch synthesizer multiple processes of selecting present heavy industrialization to implement contrast.Processing condition during multiple process see Table 3 last row.

The processing condition of table 3 embodiment 1 and comparative example 1 Fischer-Tropsch synthesis

* annotate: 1) two reactor process conditions are identical in the comparative example 1;

2) the gas agent is than the ratio that is feed gas volumetric flow rate and catalyst in reactor quality in the unit time.

The concrete data of the actual effect of technology of the present invention see Table 4.

Table 4 experimental result

Among the embodiment 1, fresh raw material of synthetic gas once passed through when first section Fischer-Tropsch was synthetic, and the CO transformation efficiency is 54.6%.Behind first section Fischer-Tropsch synthesis, contraction of gas for satisfying second section Fischer-Tropsch synthesis device inlet empty tower gas velocity, needs to replenish second section Fischer-Tropsch synthetic circulation gas, and recycle ratio is 0.76v/v.Second section Fischer-Tropsch synthetic CO per pass conversion is 61.8%, and total conversion rate reaches 81.4%.One, two sections integrated back total reaction results are: the CO total conversion rate reaches 91.7%, CO ₂Selectivity (accounting for the CO mole ratio of conversion) is 25.3%, CH ₄Selectivity (accounting for the mole ratio of total generation hydrocarbon) is 6.7%, and the hydrocarbon space-time yield reaches 0.735g/g-cat./h.

Under conditions such as identical catalyzer and reactor inlet empty tower gas velocity, temperature of reaction and reaction pressure, the integrated result of two cover separate unit reactor assemblies is during multiple process: the CO per pass conversion is 59.7%, and total conversion rate only is 83.6%, CO ₂Selectivity (accounting for the CO mole ratio of conversion) is 23.5%, CH ₄Selectivity (accounting for the mole ratio of total generation hydrocarbon) is 6.6%, and the hydrocarbon space-time yield is 0.705g/g-cat./h.During this comparative example, the recycle ratio of every reactor is 1.0v/v, promptly need two recycle gas compressors, and the recycle gas total amount has reached the fresh synthesis gas amount.Usually,, the CO total conversion rate need be brought up to operation more than 90%, need to reduce the fresh synthesis gas amount this moment, improve more than the recycle ratio to 1.5 in order to improve the CO utilization ratio.

By embodiment result as seen, technology of the present invention is compared with existing common process, under the identical fresh synthesis gas amount of finish situation, and CO ₂And CH ₄Selectivity is suitable; The CO total conversion rate is high 8 percentage points; Device is produced hydrocarbon products output (space-time yield) and is improved 4% relatively; Reduce by a recycle gas compressor; The circulating flow rate that needs descends 58%, and gas circulation compression system process cost can reduce significantly.

Embodiment 2

Present embodiment adopts technical process shown in Figure 1, after fresh feed gas is gasification, through the H that purifies and water-gas shift obtains ₂With the volume ratio of CO be 1.8 synthetic gas.

One, two section of present embodiment is all adopted Fe-series catalyst, and catalyzer is identical with embodiment 1.Processing condition are listed in the table 5.

Embodiment 3

Present embodiment adopts technical process shown in Figure 1, the H of fresh feed gas for being obtained by Sweet natural gas ₂With the volume ratio of CO be 2 synthetic gas.

One, two section of present embodiment is all adopted cobalt series catalyst, catalyzer consist of 15Co: 5Zr: 100Al ₂O ₃The preparation method uses rotary drum dehydration by evaporation, drying then for pouring the zirconium nitrate aqueous solution into according to first wetting method in 500 ℃ of baked aluminum oxide in advance in air, adds Co (NO again according to first humidity method ₃) ₂6H ₂The O aqueous solution, flood the aqueous solution of Xiao Suangu after the drying once more, as above be total to three times repeatedly, cobalt contents meets the requirements in the complex catalyst precursor thing, add a certain amount of binding agent, through extrusion, pelletizing, drying, roasting, after reduction is handled, obtain qualified cobalt series catalyst.Processing condition are listed in the table 5.

Table 5 embodiment 2 and 3 processing condition

Table 6 embodiment 2 and 3 experimental result

Common process will reach the CO total conversion rate identical with the present invention, then needs to reduce the fresh synthesis gas amount of finish, increases recycle ratio.Device capbility further descends, and recycle gas compression energy consumption further increases.

Above embodiment be with the paste state bed reactor be example present invention is described, those skilled in the art understand that above-mentioned technology and system also are applicable to fixed bed, fixed fluidized bed, fluidized-bed through after the suitable adjustment.

Certainly, the present invention also can have other embodiments, and the above is a preferred implementation of the present invention only, is not to be used for limiting protection scope of the present invention; Without departing from the spirit of the invention, those of ordinary skills are every to make various corresponding variations and modification according to content of the present invention, all belongs to the protection domain of claim of the present invention.

Claims

1. Fischer-Tropsch synthesis method may further comprise the steps:

A) first section Fischer-Tropsch synthesis

Make and contain CO and H ₂Unstripped gas enter first section Fischer-Tropsch synthesis device (102), under the effect of catalyzer, carry out Fischer-Tropsch synthesis, obtain first section Fischer-Tropsch synthesis product;

B) separation of first section Fischer-Tropsch synthesis product

Described first section Fischer-Tropsch synthesis product separated, water is separated with unconverted tail gas, obtain the unconverted tail gas (4) of hydrocarbon product, first section Fischer-Tropsch synthesis;

C) second section Fischer-Tropsch synthesis

The described unconverted tail gas (4) that obtains in the step b) is entered second section Fischer-Tropsch synthesis device (112), under the effect of catalyzer, carry out Fischer-Tropsch synthesis, obtain second section Fischer-Tropsch synthesis product;

D) separation of second section Fischer-Tropsch synthesis product

Described second section Fischer-Tropsch synthesis product separated, water is separated with unconverted tail gas, obtain the unconverted tail gas (10) of hydrocarbon product, second section Fischer-Tropsch synthesis, the part of the unconverted tail gas of described second section Fischer-Tropsch synthesis (27) is returned described second section Fischer-Tropsch synthesis device (112) circulating reaction.

2. Fischer-Tropsch synthesis method according to claim 1, wherein, the unconverted tail gas (4) of described first section Fischer-Tropsch synthesis does not return described first section Fischer-Tropsch synthesis device (102) circulating reaction.

3. according to each described Fischer-Tropsch synthesis method of claim 1 to 2, wherein, the described top product (2 that comprises Fischer-Tropsch synthesis that separates in step b) and the step d); 33) oil-water-gas separates; Preferred described b) oil-water of the top product (2) of first section Fischer-Tropsch synthesis-gas separation and/or described d) oil-water-gas separation of the top product (33) of second section Fischer-Tropsch synthesis may further comprise the steps:

At first, adopt high pressure hot separator (104; 114) carry out flash separation, obtain high pressure hot separator liquid (11; 37), high pressure hot separator gas (3; 34);

Then, with described high pressure hot separator gas (3; 34) adopt cold high pressure separator (106; 116) carry out flash separation, obtain two-phase: cold high pressure separator liquid is the blended liquid phase product (6 of light ends oil and water; 36), cold high pressure separator gas is unconverted tail gas (4; 10).

4. Fischer-Tropsch synthesis method according to claim 3 wherein, further comprises:

E) with the described high pressure hot separator liquid (11 of described first section, second section Fischer-Tropsch synthesis; 37) feed thermal low-pressure separators (117), flash separation obtains the heavy ends oil production as thermal low-pressure separators liquid (78) and thermal low-pressure separators gas (39); And

F) alternatively, with the described cold high pressure separator liquid (6 of described first section, second section Fischer-Tropsch synthesis; 36) and optional described thermal low-pressure separators gas (39) feed cold low separator (118), flash separation obtains cold low separator gas (48), light ends oil production (58), water (68).

5. Fischer-Tropsch synthesis method according to claim 3, wherein,

Described high pressure hot separator (104; 114) at 120～220 ℃, preferably 140～180 ℃ of operations down;

Described cold high pressure separator (106; 116) under 5～60 ℃, more preferably 10～50 ℃ of operations down.

6. Fischer-Tropsch synthesis method according to claim 4, wherein,

Described thermal low-pressure separators (117) is 60～200 ℃, preferred 70～180 ℃, more preferably 80～160 ℃, most preferably 90～140 ℃ of operations down;

Described cold low separator (118) is 5～60 ℃, preferred 20～50 ℃ of operations down.

7. according to each described Fischer-Tropsch synthesis method of claim 1 to 5, wherein, control in described first section Fischer-Tropsch synthesis device (102) the CO transformation efficiency, more preferably 40%～65%, further preferred 50%～60% at 30%-70%.

8. according to each described Fischer-Tropsch synthesis method of claim 1 to 7, wherein, second section Fischer-Tropsch synthesis carries out under following reaction conditions described in first section Fischer-Tropsch synthesis described in the step a) and/or the step c):

Temperature of reaction is 200～320 ℃, is preferably 235～275 ℃, more preferably 245～265 ℃;

Reaction pressure is 15～50bar, is preferably 20～40bar, more preferably 25～35bar;

Reactor inlet gas empty tower gas velocity is 10～40cm/s, is preferably 15～35cm/s, more preferably 15～25cm/s;

The reactor inlet volumetric flow of gas is 2000～50000Nml/g-cat./h with the ratio (i.e. gas agent ratio) of catalyst quality, is preferably 5000～30000Nml/g-cat./h, more preferably 8000～20000Nml/g-cat./h.

9. according to each described Fischer-Tropsch synthesis method of claim 1 to 8, wherein, described first section Fischer-Tropsch synthesis device (102) and described second section Fischer-Tropsch synthesis device (112) are one or a plurality of paste state bed reactors in parallel; The number of preferred described first section Fischer-Tropsch synthesis device (102) equals or more than the number of described second section Fischer-Tropsch synthesis device (112); For example, described first section Fischer-Tropsch synthesis device

(102) be a paste state bed reactor or a plurality of paste state bed reactors in parallel, described second section Fischer-Tropsch synthesis device (112) is a paste state bed reactor.

10. according to each described Fischer-Tropsch synthesis method of claim 1 to 9, wherein, CO and H in the described unstripped gas ₂Volume ratio be 0.67～2.2, preferred 0.8～2, more preferably 1～2, most preferably 1.4～2.

11., wherein, step a) and c according to each described Fischer-Tropsch synthesis method of claim 1 to 10) in employed catalyzer be Fe-series catalyst or cobalt series catalyst; Preferably, when adopting Fe-series catalyst, the H of unstripped gas ₂With the volume ratio of CO be 1.4～1.8, preferred 1.4～1.7, more preferably 1.5～1.7, most preferably 1.5～1.6; Preferably, when adopting cobalt series catalyst, the H of unstripped gas ₂With the volume ratio of CO be 1.8～2.2, preferred 1.9～2.1, more preferably 1.95～2.05, most preferably 2.0.

12. according to each described Fischer-Tropsch synthesis method of claim 1 to 11, wherein, the unconverted tail gas of described second section Fischer-Tropsch synthesis mixes with the unconverted tail gas of whole described first section Fischer-Tropsch synthesis, enter described second section Fischer-Tropsch synthesis device (112) then, the unconverted tail gas of preferred described second section Fischer-Tropsch synthesis is 0.5～5 with the unconverted tail gas mixed volume ratio of described first section Fischer-Tropsch synthesis, be preferably 1～3, more preferably 1.5～2.5; Preferably before mixing, remove the CO in the unconverted tail gas of described second section Fischer-Tropsch synthesis ₂For example, remove CO ₂Adopt hot salt of wormwood to take off CO ₂Method or WATER-WASHING METHOD are carried out.

13. according to each described Fischer-Tropsch synthesis method of claim 1 to 12, wherein, unstripped gas described in the step a) is synthetic gas, preferred fresh synthesis gas, further preferred synthetic gas through purification and water-gas shift.

14. according to each described Fischer-Tropsch synthesis method of claim 1 to 13, wherein, the described unconverted tail gas water-content by volume that enters described second section Fischer-Tropsch synthesis device (112) is lower than 0.05%, preferably is lower than 0.01%, more preferably less than 0.005%, most preferably be lower than 0.0001%.

15. the Fischer-Tropsch synthesis system comprises:

A) first section Fischer-Tropsch synthesis device (102) wherein accommodates fischer-tropsch synthetic catalyst, and described first section Fischer-Tropsch synthesis device (102) has at least:

First section reactor inlet is positioned at the bottom of described first section Fischer-Tropsch synthesis device (102);

First section reactor head exports, and is positioned at the top of described first section Fischer-Tropsch synthesis device (102);

First section Fischer-Tropsch synthetic wax or slurries outlet are positioned at the slurry attitude bed district of described first section Fischer-Tropsch synthesis device (102);

B) first section separation system is used for the top product (2) from described first section reactor head outlet is separated, and water is separated with unconverted tail gas, obtains the unconverted tail gas of hydrocarbon product, first section Fischer-Tropsch synthesis; Described first section separation system has:

First section separation system inlet links to each other with described first section reactor head outlet;

A plurality of first section separation system outlet comprise:

The outlet of first section hydrocarbon product and

First section unconverted tail gas outlet;

C) second section Fischer-Tropsch synthesis device (112) wherein accommodates fischer-tropsch synthetic catalyst, and described second section Fischer-Tropsch synthesis device (112) has at least:

Second section reactor inlet is positioned at the bottom of described second section Fischer-Tropsch synthesis device (112), and links to each other with described first section unconverted tail gas outlet;

Second section reactor head exports, and is positioned at the top of described second section Fischer-Tropsch synthesis device (112);

Second section Fischer-Tropsch synthetic wax or slurries outlet are positioned at the slurry attitude bed district of described second section Fischer-Tropsch synthesis device (102);

D) second section separation system, be used for the top product (33) from described second section reactor head outlet is separated, water is separated with unconverted tail gas, obtain the unconverted tail gas of hydrocarbon product, second section Fischer-Tropsch synthesis, described second section separation system has:

Second section separation system inlet links to each other with described second section reactor head outlet;

A plurality of second section separation system outlet comprise:

The outlet of second section hydrocarbon product and

Second section unconverted tail gas outlet.

16. Fischer-Tropsch synthesis system according to claim 15, wherein, described first section unconverted tail gas outlet do not connect described first section reactor inlet.

17. Fischer-Tropsch synthesis system according to claim 15, wherein, described B) first section separation system and/or described D) second section separation system comprise oil-water-air separation.

18. Fischer-Tropsch synthesis system according to claim 17, wherein, described B) first section separation system and/or described D) oil-water-gas separating system of second section separation system comprises:

High pressure hot separator (104; 114), have:

The high pressure hot separator inlet links to each other with described first section separation system inlet or described second section separation system inlet,

The high pressure hot separator liquid exit and

The high pressure hot separator pneumatic outlet;

Cold high pressure separator (106; 116), have:

The cold high pressure separator inlet links to each other with described high pressure hot separator pneumatic outlet,

The cold high pressure separator liquid exit and

The cold high pressure separator pneumatic outlet.

19. Fischer-Tropsch synthesis system according to claim 18 further comprises:

Thermal low-pressure separators (117) has:

The thermal low-pressure separators inlet links to each other with the described high pressure hot separator liquid exit of described first section separation system and/or described second section separation system,

The thermal low-pressure separators pneumatic outlet,

The thermal low-pressure separators liquid exit;

Alternatively, cold low separator (118) has:

The cold low separator inlet links to each other with described thermal low-pressure separators liquid exit and/or described cold high pressure separator liquid exit,

The outlet of cold low separator gas,

The light ends oil export,

The outlet of Fischer-Tropsch synthetic water.

20., further comprise and take off CO according to claim 18 or 19 described Fischer-Tropsch synthesis systems ₂System (109), the described CO that takes off ₂System (109) has:

Take off CO ₂The colvent inlet,

Take off CO ₂Solvent outlet,

Take off CO ₂The system gas inlet links to each other with described cold high pressure separator pneumatic outlet,

Take off CO ₂The system gas outlet links to each other with described second section reactor inlet.

21. according to each described Fischer-Tropsch synthesis system of claim 15 to 20, wherein, described first section Fischer-Tropsch synthesis device (102) and described second section Fischer-Tropsch synthesis device (112) are one or a plurality of paste state bed reactors in parallel; The number of preferred described first section Fischer-Tropsch synthesis device (102) is more than or equal to the number of described second section Fischer-Tropsch synthesis device (112); Preferably, described first section Fischer-Tropsch synthesis device (102) is one or a plurality of paste state bed reactors in parallel, and described second section Fischer-Tropsch synthesis device (112) is a paste state bed reactor.

22., further comprise according to each described Fischer-Tropsch synthesis system of claim 15 to 21:

Wax filter is arranged on the inside or the outside of described first section Fischer-Tropsch synthesis device (102) and described second section Fischer-Tropsch synthesis device (112).