WO2008142228A2

WO2008142228A2 - Method of supplying fuel to a heavy crude production unit, corresponding heavy crude production process and corresponding heavy crude production unit

Info

Publication number: WO2008142228A2
Application number: PCT/FR2008/000393
Authority: WO
Inventors: Gérard THIERY; Hélène Leroy
Original assignee: Total Raffinage Marketing
Priority date: 2007-04-25
Filing date: 2008-03-25
Publication date: 2008-11-27
Also published as: CA2681450A1; CA2681450C; FR2915554A1; RU2447356C2; RU2009143532A; FR2915554B1; WO2008142228A3

Abstract

The invention relates to a method of supplying fuel to a heavy crude production unit (10), said unit comprising: a diluent(s) supply line (12) intended to carry at least one diluent from a processing unit (11) to said production unit (10), a discharge line (13) intended to carry the heavy crude produced at the production unit, and mixed with the diluent(s) from the production unit (10) to the processing unit (11), characterized in that use is made of the diluent(s) supply line (12) to carry a mixture of fuel and diluent(s) to the production unit. A heavy crude production process according to the invention uses this supply method to carry a fuel to the production unit and use it to produce the heavy crude. The invention also relates to a heavy crude production unit implementing the production process according to the invention.

Description

METHOD FOR SUPPLYING FUEL TO A UNIT OF

HEAVY RAW PRODUCTION, PROCESS FOR PRODUCTION OF

HEAVY RAW AND PRODUCTION UNIT OF HEAVY RAW

CORRESPONDENTS.

The present invention relates to a fuel supply method of a heavy crude production unit and a method for producing a heavy crude using said feed method. It also relates to a unit for producing a heavy crude for the implementation of the production process.

Compared to conventional light crude oil, heavy crudes and extra heavy crude oils, also known as heavy or extra-heavy oils and natural bitumens, generally have a much higher proportion of heavy carbon compounds, higher sulfur, nitrogen and heavy metals. However, conventional refineries are designed to process mainly conventional light crude oil. For this reason, it is economically preferable to build an upgrader, which upgrades heavy crude to a lighter "synthetic" crude oil, which will then be transported to any conventional refinery for upgrading. be transformed into commercial products (gasoline, diesel ...).

In addition, the exploitation of heavy and extra-heavy crudes, generally defined by a density of less than 20 ° API, is particularly difficult because of their high viscosity. One of the main problems faced by oil tankers is the transportation of heavy oils such as those from the Athabasca deposits in Canada or the Orinoco oil belt in Venezuela from production sites (oil wells). heavy or extra heavy crude, oil sands extraction sites ...), up to the treatment sites (heavy crude valorization units, refineries capable of treating heavy crudes, etc.).

Several solutions have been proposed to make heavy crudes transportable. One of these solutions is to dilute the heavy crude oil or light oil fractions, which reduces the density and viscosity of the effluent, to values compatible with the specifications of the transmission lines (183.5 mPa.s at 37.7 ⁰ C and 15 ⁰ API in Venezuela and 350 mPa.s at 7.5 ° C in winter and 18.5 ° C in summer and 19 ⁰ API in Canada by example).

Two schemes are then possible. In the first scheme, the diluent is not recycled, and diluted heavy crude is sent to the refineries.

In a second scheme, the diluent is recycled when there is a heavy crudes upgrading plant. The diluted heavy crude can then be sent by pipeline to this treatment site, where the diluent is distilled off the heavy crude to be returned to the production site by a second pipeline and reused on site.

This loop is shown schematically in FIG. 1, in which a pipe 1 transports the heavy crude produced by a production unit 3 and diluted to a treatment unit 4, a pipe 2 carrying a diluent of the treatment unit 4 to the production unit 3. The diluent is mixed with the heavy crude at the level of the production unit 3 to allow its transport to the processing unit 4.

When the viscosity of the heavy crudes is not too great, they retain a certain "mobility" (ie a certain fluidity) under the conditions of pressure and temperature of the tank. It is therefore possible to produce them by conventional recovery methods, such as the simple natural depletion of the deposit, also called "cold production" insofar as it does not make use of an external supply of energy, outside the activation of the well.

Viscous heavy crudes can not be produced from a well unless previously heated or diluted. In this case, we speak of "hot production". One of the technologies used is a continuous injection of steam, and is called SAGD (Steam Assisted Gravity Drainage). This technology relies on the drilling of a pair of horizontal wells, a production well located at the base of the deposit and an injection well drilled a few meters above the former. The water vapor injected into the injection well heats the bituminous layer. The heavy fluid fluidified and the water of condensation flows by gravity to the production well, from where they are pumped to the surface.

Due to the physical mechanisms involved, both cold production and hot production only recover part of the heavy crude in place: in cold production, the recovery rate of extra heavy crude is generally less than 10%, whereas that hot production, much more efficient, can achieve recovery rates of the order of 20% or more depending on the characteristics of the field. Hot production can therefore also be applied to heavy crude oil deposits with a certain mobility in order to improve the recovery rate.

But the major disadvantage of hot production is that it requires a very high energy input. This requires fuel for furnaces and / or boilers to produce water vapor, among others.

Generally, natural gas is used as fuel. But it is not necessarily available nearby, and more, its price is a risk for the future.

Other alternative fuels, such as heavy crude oil, can be used. Thus, part of it would be used to provide energy on the production site. Nevertheless, this solution implies a reduction in the net production capacity of the oil site, reaching up to 15-20%.

Another solution is to use a solid fuel such as coal or coke, transported by land for burning.

The cost of these materials and their transportation, especially when petroleum production sites are located in areas that are difficult to access geographically, is a significant disadvantage.

It is therefore a major need to find an alternative solution to meet the growing energy needs of heavy crude production sites. To this end, the invention proposes a method of supplying fuel to a heavy crude production unit, said unit comprising:

a diluent supply line for transporting at least one diluent from a treatment unit to said production unit

an evacuation pipe intended to transport the heavy crude produced on the production unit, mixed with the diluent (s) from the production unit to the processing unit, characterized in that one uses the feed line diluent (s) to transport a fuel mixture and diluent (s) to the production unit.

Said diluent is capable of being mixed with the heavy crude produced on the production unit to allow its transport by pipeline.

The method according to the invention has the advantage of using an existing device, namely the existing pipelines, to bring a diluent, or a mixture of diluents, to the heavy crude production site, so that it can be implemented without major modification of existing facilities.

The method according to the invention can also be implemented "on demand", that is to say according to the energy needs of the production site, by sending more or less fuel, or not at all as it is the case for the classic diluent loop. In addition, the method according to the invention can be used in batch mode ("batch" in English).

Advantageously, the fuel is a hydrocarbon fraction.

Preferably, use will be made of a heavy hydrocarbon fraction, generally difficult to recover, having a carbon residue.

Conradson CCR greater than or equal to 10% by weight, and preferably greater than or equal to 15% by weight, and even more preferably greater than or equal to 20% by weight. The hydrocarbon fraction will for example result from the treatment of a heavy crude by said processing unit. However, it will preferentially use a hydrocarbon fraction from the processing of heavy crude produced by said production unit.

The processing unit makes it possible to perform a valuation

("Upgrading"), which consists of converting heavy oil into a product whose density and viscosity resemble those of a conventional light oil. Such a processing unit (upgrading plant) generally comprises several units: atmospheric and vacuum distillation units, deasphalting units. coking units. hydrocracking units (in fixed bed / boiling bed / slurry bed). hydrotreating units.

It is possible to use a hydrocarbon fraction chosen from the atmospheric distillation residue, the vacuum distillation residue, the deasphalting pitch and the hydrocracking residue derived from the treatment of a heavy crude, which will preferably be the heavy crude produced by the said distillation unit. production.

Advantageously, the diluent is chosen from light cuts or petroleum derivatives such as condensate, naphtha (in particular, coker naphtha), kerosene, diesel, LCO, distillate mixtures, etc.

Alternatively, the diluent is selected from organic solvents such as alcohols such as methanol, ethanol, propanol, isopropanol and hexanol, esters and ethers such as

TAME, as well as synthetic paraffins from the treatment of gas or biomass.

Preferably, and in particular when the distance separating the processing unit from the production unit is large, the fuel and the diluent (s) are chosen so that the fuel-diluent (s) mixture has an S-value stability limit> 1

(ASTM D7157 standard), preferentially S-value> 1, 35. this allows to avoid deposits in the pipeline due to instability of the fuel-diluent mixture.

The higher fuel / diluent ratio is limited by the amount of diluent that is required to form a pipeline transportable product. Thus, preferably, the upper limit of the fuel / diluent ratio is between 70% and 80%, and sufficient for the mixture to be transportable.

Generally the lower limit of the fuel / diluent ratio is between 10% and 20%. Since the relationship between the viscosity of the mixture and the volume of diluent added is exponential, the maximum decrease in viscosity corresponds to a certain level of solvent which need not be exceeded.

The invention also relates to a method for producing a heavy crude by means of a heavy crude production unit, said unit comprising:

a diluent feed line for transporting at least one diluent from a processing unit to said production unit,

an evacuation pipe intended to transport the heavy crude produced on the production unit, mixed with the diluent (s) from the production unit to the treatment unit, said method comprising:

(a) conveying a fuel mixed with at least one diluent according to the fuel supply method according to the invention,

(b) separating the fuel and diluent production unit.

Said diluent is capable of being mixed with the heavy crude produced on the production unit in order to allow its transport by pipeline,

The step (b) of separation of the fuel and the diluent can be carried out either by distillation or in a simpler manner by a liquid-vapor separation carried out continuously (Flash in English). In Indeed, the fuel and the diluent used according to the present invention generally having very different characteristics, they can be easily separated completely, by simple flash.

This separation step can be completed, depending on the type of the hydrocarbon fraction recycled with the diluent, by other physico-chemical separation treatments (eg deasphalting).

Advantageously, this process comprises a step of combustion or gasification of the separated fuel in the production unit.

The invention also relates to a unit for producing a heavy crude for the implementation of the production process according to the invention, said unit comprising: - a feed line of diluent (s) intended to carry at least one diluent from a processing unit to said production unit,

an evacuation pipe intended to transport the heavy crude produced on the production unit, mixed with the diluent (s) from the production unit to the treatment unit, characterized in that it comprises a separating device connected to the supply line diluent (s), said device being capable of separating the fuel-diluent mixture circulating in said supply line.

Advantageously, the unit comprises a device for gasification or fuel combustion separated by means of the separation device, said combustion device being able to produce the energy necessary for the extraction of heavy crude using said fuel. As a combustion device, use for example a fluidized bed boiler (CFBB).

The feeding method according to the invention has several advantages: - use of an existing device (pipelines already in place) requiring only the addition of a separation device on the site of production and possibly debottlenecking of the existing diluent pipeline (pumping station); implementation "on demand", according to the energy needs of the production site. - advantageous implementation when the treatment site comprises a coker unit fed with vacuum residue: during a general debottlenecking of the site without touching the coker, the vacuum residue supplement generated by the treatment supplement of extra heavy crude being sent to the place of production for use as fuel.

The invention is now described with reference to the appended non-limiting drawings, in which:

Figure 1 is a schematic representation of the pipelines connecting a heavy crude production unit to a processing unit;

Figure 2 is a schematic representation of a processing unit and a production unit according to the invention.

FIG. 2 shows a unit 10 for producing a heavy crude connected to a processing unit 11 for the heavy crude produced by means of supply and evacuation lines 13. The supply line 12 supplies a diluent to the production unit, the evacuation pipe carrying the heavy crude product mixed with the diluent to the processing unit. According to the method according to the invention, the supply line 12 will be used to transport the fuel from the treatment unit mixed with the diluent to the production unit.

The production unit 10 according to the invention is provided with a separating device 14 for the separation of the fuel and the diluent supplied by the supply line 12. The separated fuel C is conveyed to a combustion device 15 for the production of energy for the production of heavy crude BL. The separate diluent D is, for its part, mixed with the heavy crude produced for its transport to the treatment unit via the evacuation pipe 13. The treatment unit comprises a separation device 16 of the diluent and the crude that separates diluent D to return it to the production unit via line 12, and the heavy crude BL. This separation is generally carried out by atmospheric distillation.

The heavy crude then undergoes vacuum distillation in a column 17. The RSV vacuum residue produced, which can represent up to about 50% of the heavy crude, can be processed in a coker unit 18. The treatment unit can also be provided with a deasphalting unit 19 for treating the residue under vacuum RSV.

When the processing unit comprises a coking unit 18, the vacuum residue is converted into coke and lighter fillers. Part of this residue can be sent via a pipe 20 to the inlet of the feed pipe 12 in which it is introduced in admixture with the diluent, to be transported to the production unit and to serve as fuel after separation. 'with the diluent.

When the processing unit comprises a deasphalting unit 19, the vacuum residue is converted into deasphalted oil DAO and deasphalting pitch. Deasphalting pitch can be returned via a pipe 21 to the inlet of the supply line 12 in which it is introduced in admixture with the diluent, to be transported to the production unit and to serve as a fuel after separation. with the diluent.

EXAMPLES

The following examples illustrate the invention and its advantages without, however, limiting its scope. Several fuel mixtures and diluents were tested.

The fuels tested are as follows:

- Vacuum residue (RSV) of the Venezuelan crude extra-heavy Zuata

- Slurry from pentane deasphalting of thermally produced Athabasca bitumen (SAGD); heavier liquid product.

The properties of the fuels are as follows: Table 1: properties of the fuels tested

The solvents tested are as follows:

- Light Naphtha

- Heavy Naphtha

- Naphtha total (32% light Naphtha + 68% heavy Naphtha)

- Kerosene cut

- Naphtha of coker

Table 2: Properties of the diluents tested

In this non-limitative example, we imposed, moreover, the following constraints:

(1) The mixture must have a stability reserve, (S-Value> l, ASTM D7157 standard) sufficient to avoid settling problems.

(2) the mixture must meet the specifications of the pipelines:

- In Venezuela:

- 183.5 mPa.s at 37.7 ° C max, 15 ° API min.

- In Canada :

- 0,935 of max. and 350 mPa.s max, at 7,5 ⁰ C in winter

- 0,935 of max. and 350 mPa.s max. at 18.5 ° C in summer.

The diluent and fuel mixtures were studied for two compositions: 85% by diluent mass + 15% by mass of fuel,

- 70% by weight diluent + 30% by combustible mass,

The test results are summarized in Tables 3 and 4. The main conclusions are as follows:

(a) Unstable mixtures can be classified into two categories:

Highly unstable: two phases appear (no miscibility). - Slightly unstable: non-miscibility is not visible to the eye but a measure of stability or a simple test to the task show that the product is unstable (S-value <l).

(b) The following mixtures do not exhibit a sufficient reserve of stability:

70/30 heavy naphtha / pitch, 70/30 total naphtha / pitch, 85/15 cut kerosene / pitch. 85/15 light naphtha / RSV 70/30 light naphtha / RSV

(c) Stable mixtures (S-Value> l, 35) respect the density constraint of the pipelines.

(d) In terms of viscosity, all the tested mixtures comply with the specifications except for the 30% pitch + 70% kerosene cut that does not respect the winter constraint of Canadian pipelines.

Claims

CLAIMS:

A method for supplying fuel to a heavy crude production unit (10), said unit comprising: - a feed line (12) diluent (s) intended to carry at least one diluent from a unit of processing (11) to said production unit (10),

an evacuation pipe (13) for conveying the heavy crude produced on the production unit, mixed with the diluent (s) from the production unit (10) to the treatment unit (11) , characterized in that the supply line (12) is used by diluting (s) to transport a fuel mixture and diluent (s) to the production unit.

2. Fuel supply method according to claim 1, characterized in that the fuel is a hydrocarbon fraction.

Fuel supply method according to claim 2, characterized in that the carbon Conradson residue.

CCR of the hydrocarbon fraction is greater than or equal to 10% by weight, and preferably greater than or equal to 15% by weight, and even more preferably greater than or equal to 20% by weight.

4. fuel supply method according to claim 2 or 3, characterized in that the hydrocarbon fraction is derived from the treatment of a heavy crude by said processing unit, preferably the treatment of heavy crude produced by said production unit .

5. fuel supply method according to one of claims 2 to 4, characterized in that the hydrocarbon fraction is selected from the atmospheric distillation residue, the vacuum distillation residue, the deasphalting pitch and the hydrocracking residue, from the treatment of a heavy crude, preferably the treatment of heavy crude produced by said production unit.

6. fuel supply method according to one of claims 1 to 5, characterized in that the diluent is selected from light cuts or petroleum derivatives such as condensate, naphtha, coker naphtha, kerosene, diesel, LCO, distillate mixtures ...

7. A fuel supply method according to one of claims 1 to 5, characterized in that the diluent is selected from organic solvents such as alcohols such as methanol, ethanol, propanol, isopropanol and ltiexanol esters and ethers such as MTBE, TAME, as well as synthetic paraffins resulting from the treatment of gas or biomass.

8. fuel supply method according to one of claims 1 to 7, characterized in that the fuel and the (s) diluent (s) are chosen so that the fuel-diluent mixture (s) has a stability limit S-value> 1, preferably S-value> 1, 35.

9. fuel supply method according to one of claims 1 to 8, characterized in that the lower limit of the fuel / diluent ratio is between 10% and 20%

10. Fuel supply method according to one of claims 1 to 9, characterized in that the upper limit of the fuel / diluent ratio is between 70% and 80%.

A method of producing a heavy crude by means of a heavy crude production unit (10), said unit comprising: - a feed pipe (12) diluent (s) for transporting at least one diluent from a processing unit (11) to said production unit (10),

an evacuation pipe (13) for conveying the heavy crude produced on the production unit (10), mixed with the diluent (s) from the production unit (10) to the treatment unit

(H), said method comprising: (a) conveying a fuel in admixture with at least one diluent according to the fuel supply method according to one of claims 1 to 10,

(b) separating the fuel and diluent production unit.

12. Process for producing a heavy crude according to claim 11, characterized in that it comprises a step of combustion or gasification of the separated fuel in the production unit.

13. Production unit (10) of a heavy crude for the implementation of the production method according to one of claims 11 or 12, said unit comprising: - a feed pipe (12) diluent (s) for transporting at least one diluent from a processing unit (11) to said production unit (10),

an evacuation pipe (13) for conveying the heavy crude produced on the production unit, mixed with the diluent (s) from the production unit (10) to the treatment unit (11) , characterized in that it comprises a separation device (14) connected to the supply line (12) by diluting (s), said device being able to separate the fuel-diluent mixture circulating in said supply pipe.

Production unit (10) according to claim 13, characterized in that it comprises a device for gasification or combustion (15) of the separated fuel by means of the separation device (14), said combustion device (15) being able to produce the energy required to extract the heavy crude using said fuel.