PATENT APPLICATION
TITLE: INSULATED PIPE
INVENTOR: F. GLENN LIVELY
TECHNICAL FIELD
This invention relates generally to pipe coating More specifically, embodiments of this invention relate to insulation layer or layers on a pipe's circumference, where such layers may be abrasion resistant, corrosion resistant and provide thermal insulation to the pipe's contents The insulation may be placed on a pipe's exteπor circumference or surface, inteπor circumference or surface, or both The pipe or a pipeline including the pipe, is intended for use in fluid transport, generally submerged Description
Introduction
Embodiments of my invention concern certain pipe insulation and pipe coatings
In embodiments of my invention, the insulation may be applied to the inteπor circumference or surface of pipes or pipe lines, at least a first layer insulation may be applied to the pipe surface preceeded by an optional pnmer, and optionally at least a first layer of an abrasion resistant coating may be applied to the insulation
In other embodiments of the present invention the insulation may be a Ceramic-Cover™ 100, (manufactured) Therma-Cote Inc of Atlanta, Georgia,
USA. and may be descπbed as a viscous solution of ceramic and acrylic latex Or the insulation may be Therma-Coat from Hempel Coatings, Conroe, TX The topcoat or abrasion resistant coating, EC-376F, may be manufactured by Industπal Environmental Coatings Corp of Pompano Beach, FL Embodiments of this invention further include certain methods of applying the insulation and the optional coating Also contemplated are pipes and pipelines
_.?.
coated, on the inteπor circumference and/or surface, exteπor circumference and/or surface, or both, with an optional pπmer, with the insulation and/or the abrasion resistant coating The insulation and optional abrasion resistant coatings have properties rendeπng them supeπor to, and unique from, previously available pipe insulation and coating The pipe insulation and optional abrasion resistant coatings descπbed herein are suited for use in producing certain classes of insulated, submerged pipes or pipelines Those skilled in the art will appreciate that numerous modifications to these embodiments can be made without departing from the scope of the invention For example, although gas and crude oil pipes and pipelines, insulated on their interior, are exemplified herein, the insulated pipelines may be made using combinations of other coatings and other surfaces to be coated such as the exteπor or a combination of exteπor and inteπor surfaces To the extent my descπption is specific, it is solely for the purpose of illustrating embodiments of my invention and should not be taken as limiting the present invention to these embodiments
Definition of Terms and Tests:
Density ASTM D-793
Compressive Strength ASTM D- 1621
R value, Thermal Resistance ASTM C-l 77-85 k, Thermal Conductance ASTM C-l 58
Adhesion to Steel ASTM D-4541
Primer
A water and chemical resistant pπmer may optionally be applied directly to the steel surface of the pipe being insulated, between the pipe and a first layer of insulation When a pipeline is installed offshore on the seafloor it may have high spots and low spots due to the undulation of the seafloor In the low spots water may accumulate on the inteπor of the pipe This water may come from hydrostatic testing of the pipeline or water entrained m the fluids earned by the pipeline Such water may cause corrosion, called "6 o'clock" corrosion, for its location on the bottom of a pipeline as one would view a cross section Should water penetrate the layers of insulation and the topcoat on the inteπor of the pipe,
lt could cause coπosion, resulting perhaps in a leak Particularly troublesome is the presence of carbomc acid or hydrochloric acid in the water Occasionally oil and gas will contain small amounts of coπosive gases such as carbon dioxide or hydrogen sulfide When either of these gases are dissolved m water, acid is created that may attack the steel surface of the pipe causing failure of the pipe
The use of a pπmer between an insulation layer and the steel pipe surface may mitigate such a problem Many types of pπmers are available and will be known to those of ordinary skill in the art, one type is a phenolic pπmer such as EP-10, which is manufactured by Morton (Reading, PA) This pπmer may be applied at a thickness that may average 1 mil and may be cured in an oven at 300°F for one hour Other pπmers may be used, some of these pπmers may not require oven cuπng, but may be air cured Insulation
In embodiments of the present invention, the insulation may be a Ceramic- Cover™ 100 (CC-100), manufactured Therma-Cote Inc of Atlanta, Georgia,
USA, or the insulation may be Therma-Coat coating manufactured by Hempel Coatings, refeπed to above Polyurethane foam (PU), may have a heat or thermal conductance (k) from 0 65 to 0 1 BTU/sq ft , hr , F° The conductance of the insulation of embodiments of my invention will be < 0 4 BTU/sq ft hr F°, or < 0 3 BTU/sq ft hr F°, or < 0 08 BTU/sq ft hr F°, or < 0 07 BTU/sq ft hr P, or <
0 06 BTU/sq ft hr F°, or < 0 05 BTU/sq ft hr F°, or < 0 04 BTU/sq ft hr F°, or < 0 03 BTU/sq ft hr F°, or < 0 02 BTU/sq ft hr F°, or > 0 001 BTU/sq ft hr F°, or > 0 003 BTU/sq ft hr F°, or > 0 005 BTU/sq ft hr F° The density of the insulation, as determined by ASTM D-792, may be > 0 1 g/cm
3, or > 0 2 g/cm
3, or > 0 3 g cm
3, or > 0
or < 0 75
or < 0 65 g/cm
3-
, or < 0 55 g/cm3 The density of common πgid urethane foams is in the range of 0 012 - 0 025 g/cm3 The compressive strength of the insulation of embodiments of my invention, may be > 100 psi, or > 200 psi, or > 400 psi , or > 800 psi, or > 1500 psi, or > 2,000 psi , or > 2500 psi or > 3000 psi, or > 3500 psi, or > 4000 psi
The compressive strength of ngid urethane foams is in the range of 15-60 psi (10% deflection)
The insulation may be characteπzed by its R value (Thermal resistance °F hr ft' /BTU) per applied inch Other types of insulation typically have Thermal resistance as follows cork board typically has an insulation value of about 3 33 R value per inch; rock cork about 3 9 R value per inch, expanded polystyrene about 3 0 R value per inch, and polyurethane foam 5-9 R value per inch The insulation of embodiments of the present invention may be > 5 R value per inch, or > 10 R value per inch, or > 12, or > 14 R value per inch, or > 25 R value per inch, or > 35 R value per inch, or > 40 R value per inch, or > 45 R value per inch, or > 50 R value per inch, or > 60 R value per inch or < 400 R value per inch, or < 300 R value per inch, or < 200 R value per inch, or < 150 R value per inch, or < 125 R value per inch Other insulation is contemplated as long as it provides the insulation values stated herein Adhesion to steel, of the insulation of embodiments of my invention, as determined by ASTM D-4541, may be > 1000 psi, or > 1500 psi, or > 1700 psi, or > 1800 psi, or > 2000 psi, or > 2200 psi, or > 2300 psi
The CC-100 insulation is descπbed by its manufacturer (Therma-Cote) as a propπetary viscous solution of ceramic and acrylic latex The insulation is also descπbed as an 84% solid latex, high density mateπal The ceramic portion of the
CC-100 insulation is descπbed as an asymmetπcal particle, of amorphous shape Such a shape is substantially non-spheroidal However, I also contemplate spheres or sphereoidal shapes for the ceramic portion insulation The insulation may also contain glass microspheres The ceramic or glass portion of the CC-100 insulation will be > 5% (volume), or > 7%, or > 9%, or < 25%, or < 20%, or < 15% These volumetπc measurements are after substantially all of the volatiles and/or evaporative ingredients have been removed
The Therma-Coat insulation is characteπzed by its manufacturer (Hempel) as a high solids epoxy, 84+% solids (volume) and/or 86+% solids by weight The Therma-Coat insulation is substantially free of phenolics By substantially free of
phenolics, I intend that < 5 weight percent, or < 3 weight percent, or < 1 weight percent, or 0 percent of the high solids epoxy will be phenolics This substantial freedom of phenolics relates to the insulation of embodiments of my invention and not to the optional primer or optional top coat, which may include phenolics The Therma-Coat (Hempel) insulation may use microspheres of glass, ceramic spheres, amorphous ceramic or glass shapes, spheroidal ceramic or glass shapes, non-spheroidal ceramic or glass shapes, or combinations thereof The ratio of glass to ceramics in the organic matπx, after volatilization and or evaporation may be 10 90 to 90 10 or 20 80 to 80 20, or 30 70 to 70 30, or 40 60 to 60 40 The ratio of both glass and ceramic to the organic components, after volatilization and/or evaporation may be 10 90 to 90 10, or 20 80 to 80 20, or 30 70 to 70 30, or 40 60 to 60 40 The insulation may be applied by any conventional method, such as rolling, brushing, troweling, or spraying In a typical installation, the insulation will be applied to the inteπor surface or circumference of the pipe, the exteπor surface or circumference of the pipe, or both Optionally, a pπmer w ll be placed directly on the pipe surface or surfaces, followed by the insulation descπbed herein
While the manufacturers of these products state that no specific surface preparation may be necessary, the surface may be prepared, by methods known to those of skill in the art, to reduce or eliminate any oils, dirt, or other potential contaminants on a pipe's surface or surfaces, that might affect the adhesion or insulation performance of the applied combination of insulation and abrasion resistant coating
In application of this insulation to a pipe, after optional surface preparation, and after an optional pπmer layer or layers applied and the insulation applied, an optional abrasion resistant coating be applied after the insulation layer or layers have cured
The surface roughness or smoothness of steel pipes is generally 0 0018 inches, while the insulation descπbed here in is generally < 0 0006 inches, or < 0 0004 inches, or < 0 0002 inches, or < 0 0001 inches, or <0 00009 inches the
insulation will also provide coπosion protection to the surface or surfaces to which it is applied
The surface temperature of the pipe upon which the insulation may be ambient or up to 150°F Application in the range of from 32°F to 460°F is also contemplated
Applications of the insulation may be at a total thickness of > 2 mils, or > 5mιls, or > 10 mils, or > 20mιls, or > 25 mils, or < 100 mils, or < 90 mils or < 85 mils Or in other embodiments of my invention, the insulation can be applied in one coat at > 2 mils or > 5 mils, or > 10 mils or > 15 mils, or > 25 mils, or < 60 mils, or < 50 mils or < 40 mils thickness, or in several coats or layers, 2, 3, 4, 5, 6,
7. 8, 9. 10 or more layers, to these total thicknesses The layers may be the same thickness or different
Another insulating mateπal that may be used is a product known as Super- Therm® Super-Therm is a ceramic coating that is said to utilize three types ceramic particles to achieve results Two of the ceramics are said to reflect heat and the third is said to prevent heat loss by conduction It is said by the manufacturer to be made with two acrylics and one urethane It completely cures in 7-10 days and may be applied within a temperature range of 40°F up to 110°F Hot Box Testing indicates that this mateπal to be a thermal resistor that is said to be as effective as fiberglass with an equivalent rating of R19 (per inch) Thermal
Conductivity of this mateπal has been tested with a reported range from 0 00543 watts/cm °K up to 0 00640 watts/cm °K Insulation coefficients are reported by the manufacturer to be 0 13 BTU/ft2 hr F° or m metπc terms- 0 019 metπc watts/meter kelvm° Another insulation product that may also be used where the insulation value is provided by hollow glass (mιcro)spheres This product is called Biotherm® 453 and is manufactured by TFT of Houston, TX This mateπal is said by its manufacturer to be a pπmaπly epoxy resm with propπetary polyamines It is further said to have low volatile organic compounds (VOC's) and is normally trowel applied but may be spray applied
The use of the insulation layer or layers, without the use of a topcoat, is also contemplated, such insulation-only applications may include the optional pπmer
Abrasion Resistant Coating Optionally, one or more layers of a topcoat, such as EC-376F, manufactured by Industπal Environmental Coatings Corp of Pompano Beach, FL, may be used as the topcoat or abrasion resistant coating, generally applied to the insulation layer or layers
EC-376F is descπbed by the manufacturer to be a specially formulated high performance. 100% solids, flexibihzed epoxy phenolic that is said to demonstrate excellent adhesion, resistance to thermal and mechanical shock and excellent chemical and physical resistance m a wide range of crude and refined petroleum products It is further descπbed as a thick-film epoxy mateπal that exhibits excellent performance characteπstics when evaluated against other thick- film epoxy coatings in tthe following tests
♦Standard Atlas Cell Test (Modified NACE TMO 174-91) ♦Pressunzed Atlas Cell Test (Modified NACE TMO 174-91 ) ♦Autoclave Test (NACE TMO 1 85-88) ♦Impact Test (ASTM G 14-88) ♦Abrasion Resistance (ASTM D 4060-90)
♦Cathodic Disbondment (ASTM G95) ♦Adhesion Pull-Off Strength (ASTM D4541-89) ♦Flexibility (Modified CSA Z245, 20-M92) ♦Hardness (Shore D) ♦Electrochemical Impedance Spectroscopy (E I S )
Epoxy coatings generally may not be suited for high temperatures (above 225°F) Epoxy coatings may be generally low in adhesion (900-1000 psi to the substrate) where EC-376 has tested above 1800 psi EC-376 exhibits improved permeability values over typical epoxy coatings The chemical resistance of epoxy is generally good but depends on the type epoxy used
Additionally or alternatively, the optional abrasion resistant coating may be Ceram-Kote™ 54, manufactured by Freecom, Inc Big Spπng, Texas, USA, which is descπbed as an epoxy ceramic The coating is described as an epoxy ceramic The product may be considered to be descπbed in US 4,968.538 and 4.789,567, both fully incorporated by reference herein for purposes of US patent practice
The optional abrasion resistant coating can be applied to the insulation in 1, or 2, or 3 or 4 or more layers at a thickness of >1 mils, or > 5 mils, or > 10 mils, or < 40 mils, or < 30 mils, or < 25 mils, or < 20mιls, or < 15 mils The number of coats or layers of this abrasion resistant coating mateπal, as for the above insulation, may be more than one, and up to 10 or more
Other optional top coats are contemplated As long as the coating selected has substantially complete adhesion to the insulation, provides a desired protection of the insulation layer or layers, if necessary, and does not substantially impede the flow of product and may enhance the flow, they will be among the coatings contemplated Pipes and Pipelines
Pipes and pipelines are contemplated as substrates to be coated by the combination of insulation and optional abrasion resistant coating While generally including pipes of > 2 inches (5 cm), or < 48 inches (232 2 cm), or < 40 inches, or < 30 inches (75 cm) in inside diameter (ID), other sizes are contemplated as well The pipe will generally form some portion of a fluid delivery apparatus, such as a pipeline, including pumps, mamfolds, heaters and the like Pipe may be of any length, and when combined through conventional means (welding, coupling), may form a pipeline, again of any length The pipelines contemplated are used to transport fluids such as natural gas, crude oil, refined petroleum products (such as gasoline, jet fuel, aviation gas, kerosene, heating oil, or bunker oil) fluid chemicals, slurπes, bπne, and the like While an environment for the coated and insulated pipe or pipeline may be underwater, other uses are not precluded, such as underground, or above ground m any application where
mamtanence of some or all of a temperature difference (ΔT) between product inside the pipe and the exteπor environment is sought
In a further embodiment, at least a portion of the pipeline is submerged m water The water may be fresh, brackish or salt water The depth may be 0 1 meter to 2 kilometers or even greater depths as technology is available, are contemplated
The combination of insulation and optional abrasion resistant coatings as descπbed above may be of any total thickness, controlled by the application process and the desired control of product temperature and the environment that suπounds the pipe or pipeline The optional abrasion resistant coating is descπbed above, and each layer may be applied in one or more coating passes or application layers The amount of protection from the outside elements desired may be a consideration of the amount of insulation and or coating applied, the temperature and chemical makeup of the fluids to be transported, as well as the distance to be transported For instance product, e.g. crude oil, at 120°F as received from the wellhead, knowing the desired exit temperature traveling through water at 50°F, for two miles, will require certain levels of insulation, and the insulation may require a certain level of the optional abrasion resistant coating, both may be determined by those of ordinary skill in the art applying pπnciples of fluid transport and thermodynamics Also to be considered is the nature of the transported fluid, for instance, if the product has a substantial portion of constituents that would crystallize (or form hydrates) or m another way come out of the fluid at temperatures below the temperatures coming out of the wellhead, then the product must be desireably kept above the temperature at which the crystallization would occur. Even if the product is substantially devoid of such constituents, but would nse in viscosity at temperatures approaching that of the (lower) ambient environment, it is advantageous to reduce or eliminate the viscosity nse There may be other reasons or combinations of reasons to insulate pipes and pipelines, such uses are also contemplated. Those of ordinary skill in the art will appreciate that an effective amount of each of the insulation and the optional abrasion resistant coating layer or layers
will be applied to a given pipe for specific service Again, as above, the temperature difference between the environment and the fluid product (eg water temperature, and crude oil temperature) as well as the temperature at which the fluid product is desired to be maintained or delivered, will be determanitive of the amount of insulation, thickness and/or number of insulation layers, and optional abrasion resistant coating used By an effective amount I intend that this include not only total thickness, but also an effective number of layers making up the total thickness The layers may be equal or unequal in their thickness Fluids While natural gas, natural gas liquids, and crude oil are disclosed, any fluid, e g gas, liquid, slurry, are contemplated Other Pipeline Insulation
While the insulation descπbed herein will generally suffice for relatively long pipe runs and in water that can be cold, additional insulation schemes may be used in addition to the insulation on the inteπor of the pipe disclosed herein
For instance, buπal in a trench and/or buπal or partial buπal with finegrained bulk mateπal such as sand, and/or coarse-grained mateπal such as gravel as an addition to embodiments of my invention is also contemplated Among such techniques are those disclosed in GB 2 221 873 A (Wesminster Seaway Ans) Other techniques such as pipe in a pipe, while generally being less desirable as a sole insulation system than the insulation system discussed herein, may be used in addition to the disclosed insulation
In other embodiments of my invention, insulation of the pipeline will be accomplished substantially completely with the insulation descπbed herein By substantially completely I intend that > 95% , or > 97%, or > 99%, or 100%, of the insulation of a pipeline will come from the insulation of embodiments discussed herein Some insulation value may result from the optional abrasion resistant coating, the majoπty of the insulation value is expected to be deπved from the insulation of embodiments of my invention In another embodiment the pipe insulation will be substantially free of polyurethane (PU) foam, polyvinyl chlonde (PVC) foam, polystyrene foam (PS)
or combinations thereof By substantially free, I intend that < 10%, < 5%, < 2%, or 0% PU, PVC or PS, will be present in or on the pipe, either on its exteπor or its inteπor
In yet another embodiment, the inteπor of the pipe will be substantially free of PU, PVC, or PS foam (0%), while the exteπor may be insulated with PU,
PVC, or PS foam or a composite of PU, PVC, or PS foam and other polymeπc, bituminous or cementitious mateπals
In further embodiments, I contemplate that the pipe, insulated on its inteπor by insulation discussed herein, will be substantially free of insulation on its exteπor By substantially free, I intend < 5%, < 2%. or 0% of any exteπor coating will be made up of any mateπal referred by those of skill in the art as insulation
In another embodiment, the exteπor of the pipe may be protected from coπosion or physical damage by a coating, which may be a polymenc coating Such coating should not add more than 20%, or not more than 10%, or not more than 5% to the total insulation value of the pipe, the preponderance of the remainder of the insulation value to be provided by the insulation discussed herein Such corrosion protection will generally be located on a pipe's exteπor, but is not so limited While I contemplate pipes or piphnes with the insulation proximate the inside circumference of the pipe or pipeline (and optionally a pπmer between the pipe surface and a first layer of insulation), and the optional abrasion resistant coating proximate the inside circumference of the insulation layer or layers, other schemes are also contemplated For instance, a layer of insulation may be formed on the inside circumference of a pipe or pipeline, while the abrasion resistant coating may be on the exteπor circumference of the pipe As possible combinations descπbed below a) = insulation layer, b) = abrasion resistant coating, Pi) = pipe's intenor circumference, Po) = pipe's exteπor circumference, and η= a number 2 or greater Pi, a, b, or Pi, b, a, or Pi, a, b, a, or
Pi, a, a, ..aη, b, b, ... bη
Or, Pi, a, a, aη, b , or Pi, a , b, a, b or b, a, Po, Pi, a, b or a, Po, Pi, a, b, or a, a, aη, Po. Pi, a, a, aη, b, or b, Po, Pι, a, b, or b, bη, a, aη, Po, Pi, a, aη, b, bη or Po, Pi, bη, aη, or b, b, a,a, Po, Pi, or b, a, a, Po, Pi or bη, aη, Po, Pi, aη, bη, or b, Po, Pi, or bη, Po, Pi, or a, Po, Pi, a or a, Po, Pi, aη, or aη, Po, Pi, a, or aη, Po, Pi, aη , Po, Pi, a, or Po, Pi, aη
Other methods of insulating pipe or pipelines known to those of skill in the art may be used in conjunction with the with the insulation on the mtenor of the pipe as disclosed herem Such other methods should be additive to the techniques and matenals (insulation) disclosed herein At a minimum such techniques should not detract from the insulation provided by the insulation descπbed herein Exterior Pipe Coatings While my disclosed insulation and optional abrasion resistant coatings may be formed on the mtenor surface of the pipe, these or other coatings may be applied to the extenor surface of the pipe
Corrosion protection of an exterior surface of a pipe by any conventional means known to those of skill in the art, in addition to my disclosed insulation and optional abrasion resistant coating on the inteπor and optionally on the exterior of the pipe, is also contemplated
Such exteπor corrosion protection may include, but is not limited to, adhesive and tape (e g vinyl or polyethylene) wrapping, epoxy powder coating, other powder coating, extruded plastic (such as polyurethane, polyolefins, vinyl and the like), extruded elastomers (ethylene propylene rubber, butyl rubber, nitnle rubber, polychloroprene rubber and the like) and combinations of these techniques
Additionally, the application of the insulation layer or layers, preceded by an optional pπmer, and optionally covered by an abrasion resistant coating, to the exteπor of the pipe, in addition to the application of a similar system on the inteπor surface of the pipe is also contemplated
Also contemplated are cement or cementitious compositions used on the exteπor of pipes or pipelines in conjunction with embodiments of my invention disclosed herem
Pipe Joining and Joint Protection As pipe is joined by welding, coatings formed on the mtenor surface of the pipe pnor to welding, may be degraded by the high temperature of welding To address such a problem, various measures have been proposed Among these vaπous measures are US 5,547,228 and a Continuation-in-Part of the '228 document, US 5,566,984, both fully incorporated by reference herein for purposes of U S patent prosecution, which suggest a solution These documents suggest several constructions that are said to protect both the pipe being welded and its coating The cylindπcal coπosion bamer for pipe connections may be a non metallic matenal such as polytetrafluoro ethylene (PTFE) which may also have fibers in the polymer matπx (such as glass fibers) Use of such welding protection devices and methods, in conjunction with embodiments of my invention, are also contemplated. We further contemplate that such a cylindncal coπosion bamer may be a length of pipe, similar in size and configuration (although small enough to fit in the pipes to be welded) to the PTFE bamer, and such small length of pipe may be coated similarly to the pipe itself by methods and with mateπals disclosed herein That is, on its mtenor, an optional pπmer may be proximate the mtenor surface of the ba er covered with at least one layer of the insulation and optionally at least one layer of an abrasion resistant coating Such a system will provide insulation at the weld lines where the pipe is joined
Additional insulating layers of other mateπals such as polyurethane, polyvinyl chloπde (PVC), polystyrene and the like, either foamed or non-foamed are also contemplated
Other corrosion resistant coating or layers are also contemplated including, but not limited to asphaltics, pressure sensitive adhesives, PVC, polyethylene, impregnated paper and the like. Prospective Examples
Prospective Example 1
A 6 inch (15 24 cm) ED steel pipe is sand blasted w th garnet to clean mill scale, dirt, grease and other contaminants from the steel The gπt so blasted on the mtenor surface creates a 1 -4 mil anchor profile to aid in adhesion of the primer and/or insulation layer to the mtenor steel surface of the pipe A pnmer such as EP-10, manufactured by Morton, (Reading, PA), is applied at a thickness from 0 5 mil to 1 mil and is cured by heat for 30 minutes to one hour at 300°F The pπmer is applied directly to gπt blasted steel surface pnor to the application of the first insulation layer The pπmer is spray applied using an automated coating lance that reaches from the entry end of the pipe to the far end When the retraction of the lance begins, the pnmer is applied by pressure through a spray tip on the end of the lance at 360 degrees to cover the mtenor surface at the thickness stated above The pipe is heated to a steel temperature of 150°F A coating lance is inserted through the pipe and 40 mils of insulation Ceram Cover® 100 is applied using an airless spray tip that spins creating a 360° spray pattern The density of the insulation, as determined by ASTM D-792 is 0 41 g/cm3
The pipe is then moved to a cure oven with a temperature of 160°F -175°F, and remains in the oven at the temperature for 10 minutes Then a coat of Envirohne ® EC-376 (Enviromental Coatings Corp , Pompano Beach FL) is applied to an additional (m addition to the thicknesses of insulation) thickness of 10 to 15 mils After the abrasion resistant epoxy coating or top coating is applied and allowed to cure for 1 hour, a wet sponge holiday detection lance is inserted into the pipe which detects holidays or pinholes If a pmhole is detected, the coating lance is re-mserted to that portion or portions where the pmhole is detected and additional abrasion resistant epoxy coating is applied Additional prospective examples are made to demostrate the effectiveness of the application of multi-layers of the insulation The examples represented in Tables II and IV are two different applications of insulation, and Table V represents bare steel with no coating, pnmer, or insulation
This compaπson is between a steel pipe insulated with 40 mils of the insulation in one layer (Table IV), and a similar steel pipe insulated with 40 mils
of the insulation but with four ten mil layers (Table II) The assumptions, conditions and results are found in Tables I-IV
All examples have an initial oil temperature of 140°F and are operating in an environment of 36°F water The pipe is 6 inch With one layer of insulation at 40 mils thickness at a flow rate of 10,000 baπels per day (bbl/day), the oil comes to 100°F in a distance of 4 56 miles In the example with four ten mil layers (total again 40 mils) of insulation the oil does not come to 100°F until 17 11 miles, an increase over the single layer of 40 mils of over 275% Also by contrast, the uninsulated (bare steel pipe, Table V) pipe comes to 100° F at (1 5 miles) In the tables which follow, the following abbreviations are used
Outside diameter do
Inside diameter dt cross sectional area A q Heat flow from oil through (insulated) pipe, m BTU/hr
P/L Pipeline
T° F Temperature, degrees Fahrenheit
Ti Temperature inside of pipe/insulation
To Temperature on outside of pipe
Conclusion
The present invention has been descnbed in considerable detail with reference to certain versions thereof, other versions are possible For example, while steel pipes insulated on their inteπor circumference for transport of hydrocarbons have been exemplified, other uses are also contemplated
Therefore, the spiπt and scope of the appended claims should not be limited to the descnption of the versions contained herein
Table I Oil Flow in Pipeline
Pipeline 6" Oil-steel film conductance. Uo-s 5 Btu/ft2. hr. °F d 6 625 inches Water-steel conductance. Us-w 4 Btu/ft2. hr. °F d, 5 761 mches Steel thermal conductivity, ks 312 Btu/ft2. hr. °F/ιn
Length 8 miles Od specific heat. Ho 0 5 Btu/Lb. °F
X-sect Area 0 1810186 Ft2 To. temperature of oil
Outer Surf Area. S 1 7344209 Ft2 Ft Tw, temperature of water
Fluid 40 API (6 87 Fluid volume 0 181 Ft3 Lb/gal)
Flowrate 10000 BBL/Day 1 354 gallon
(38.99287
Ft3/mm)
Fluid Velocity 215 40812 Weight w Ft/mm
Flow Transit Time 3 2682148 Hours
Wt Of 1-Ft Section of 9 3021101 Lb
Oil Temp (a Entry 140°F
Outside Water Temp 36°F
Internally CC Coated 4 layers CC-Oil film conductance, Ucc-o 5 Btu/ft2, hr, °F
10 mils each Steel-CC conductance, US-cc 3 83 Btu/ft2. hr. °F CC-CC layer conductance, Ucc 0667 Btu/ft2. hr, °F
Diameters 5 741 d4 (1st CC thermal conductivity, kcc 0 064 Btu/ft2. hr. °F/ιn layer)
5 721 d3 (2nd layer)
5 701 d2 (3rd layer)
5 681 dl (4th layer)
X-sect Area 0 1760261 Ft2
Fluid Velocity w/CC 221 5176 Ft/min
Flow Transit Time. 3 1780771 Hours
Wt Of 1-Ft Sect Of Oil 9 045557 Lb
Where q = S x ( - 1 „ do 1 do d, d. > f l l ~ l ) do do d„ 1 1
.. _. + lOge - + — - x — + — + — + loge — + + di Ucc^, 2 x 1^ di Ucc v d2 d3 c_ J 2 x 1c, d, d, Us-cc Uw-S the ttme required for oil temperature to drop 10T ΔT x q = w x Ho x 10°F
Tabie D
CC Coated Pipe Output Results
Oil Flow in Pipeline
4 Layers of CC
(Total thickness of 40 mils)
10 mils/layer 10,000 BOPD q = 0.3225" (Ti-To)
Table m
Oil Flow in Pipeline
Pipeline 8'". schedule 80 Oil-steel film conductance. Uo-s 5 Btu ft2. hr. °F
OD 6 625 inches Water-steel conductance. Us-w 4 Btu/ft2. hr. °F
ID 5 761 inches Steel thermal conductivity ks 312 Btu/ft2. hr °F/ιn
Length 8 miles Od specific heat. Ho 0 5 Btu/Lb. °F
X-sect Area 0 1810186 Ft2
Outer Surf Area 1 7344209 Ft2/Ft
Fluid 40 API (6 87
Lb/gal)
Flowrate lOOOO BBL Dav
(38 99287
Ft3/mιn)
Fluid Velocity 215 40812 Ft/mm
Flow Transit Time 3 2682148 Hours
Wt Of 1-Ft Section 9 3021101 Lb
Oil Temp ( ) Entrv 140°F Outside Water Temp 36°F
Internally CC Coated 1 lavers CC-Oil film conductance. Ucc-o 5 Btu/ft2. hr, °F
40 mils each Steel-CC conductance. US-cc 3 83 Btu/ft2. hr, °F
CC-CC layer conductance. Ucc 0 667 Btu/ft2. hr. °F 5 681 dl ( 1" layer) CC thermal conductivity, kcc 0 064 Btu/ft2, hr. °F/ιn
X-sect Area 0 1760261 Ft2
Fluid Veloctn w/CC 221 5176 Ft mm
Flow Transit Time 3 1780771 Hours
Wt Of 1-Ft Sect Of 9 045557 Lb Oil
Externally CC Coated 1 lavers CC -Water film conductance. 5 Btu/ft2. hr. °F Ucc-w
20 mils each (Estimated)
6 665 d3 (outer layer OD)
Outer Surf Area 1 74489029 Ft2/Ft
Table IV
Internal CC Coated Pipe Output Results
Oil Flow in Pipeline
One Layer of CC
0 mils/layer ,000 BOPD q = 1.2082" (Ti-To)
Table V
Bare Steel Output Results
Oil Flow in Pipeline
,000 BOPD