Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
  • F17D—PIPE-LINE SYSTEMS; PIPE-LINES
  • F17D1/00—Pipe-line systems
  • F17D1/02—Pipe-line systems for gases or vapours
  • F17D1/04—Pipe-line systems for gases or vapours for distribution of gas
  • F17D1/05—Preventing freezing
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
  • C09K8/00—Compositions for drilling of boreholes or wells; Compositions for treating boreholes or wells, e.g. for completion or for remedial operations
  • C09K8/52—Compositions for preventing, limiting or eliminating depositions, e.g. for cleaning
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10L—FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G, C10K; LIQUEFIED PETROLEUM GAS; ADDING MATERIALS TO FUELS OR FIRES TO REDUCE SMOKE OR UNDESIRABLE DEPOSITS OR TO FACILITATE SOOT REMOVAL; FIRELIGHTERS
  • C10L3/00—Gaseous fuels; Natural gas; Synthetic natural gas obtained by processes not covered by subclass C10G, C10K; Liquefied petroleum gas
  • C10L3/003—Additives for gaseous fuels
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
  • C09K2208/00—Aspects relating to compositions of drilling or well treatment fluids
  • C09K2208/22—Hydrates inhibition by using well treatment fluids containing inhibitors of hydrate formers

Definitions

• compositions that control the formation of crystalline hydrates in various systems, most notably, gas and oil transmission pipeline systems.
• the compositions are comprised of carbon dioxide sorbing polymers that also have the capability of driving the formation of hydrate crystals into the polymeric matrix.
• Crystalline hydrates can form in oil and gas pipelines carrying oil and gas if the chemical composition of the produced fluids includes water, either or both of ethane or methane with carbon dioxide and sometimes, other hydrocarbon gases and/or sulfur dioxide. In addition to the chemical composition, there is a need for a driving force for such hydrate nucleation involving the physical and environmental conditions.
• the fluid composition generally is at an elevated temperature, typically above 70° C. and it will cool to a lower temperature, typically below 16° C., whereby the gases and water become super saturated and crystallize from solution at the lower temperature.
• the pipeline linking the sub-sea oil producing well to the processing platform is the crucial environment for the formation of the hydrate crystals.
• the surrounding seawater with temperatures that are about 4° C. to about 6° C. cools the pipeline that is carrying the produced fluids and obviously, the oil or gas contained therein.
• Prior art methods for controlling the formation of hydrate crystals in pipelines include the continuous injection of methanol, ethanol, or glycol; offshore dehydration of the gas so produced; warming fluids under normal flow conditions through insulation; heating flow lines, and using low doses of chemical inhibitors for threshold hydrate inhibition, kinetic inhibitor polymers, surfactants and emulsions, and anti-agglomerate polymers and surfactants.
• Methanol and glycol are currently practiced but the environmental and financial costs are high. Methanol and glycols are added to pipeline fluids at about 30 to 50% by weight of water co-produced. The costs are high but the logistics for supply and storage offshore and more importantly pumping to sub-sea producer wells are significant and cumbersome.
• the threshold and kinetic inhibitors function to prevent the growth of hydrate crystals and act essentially like salt acts to depress the freezing point of water.
• the tolerance is not as great as the industry requires and they fail in the majority of demanding situations.
• surfactants and polymers such as polyvinyl pyrrolidone or polyvinyl pyridine, or polyvinyl caprolactum.
• the polymers disclosed herein are chelating polymers capable of interacting with charged gaseous molecules such as the carbon dioxide by removing the carbon dioxide or more practically by scavenging for the carbon dioxide to encourage the methane and/or ethane hydrate structures to form within the embodiment of the polymer substrate structure. Such formation will encapsulate the seeded hydrate structure thus preventing the hydrate seeded structures from agglomerating as would have been the case if formed within the pipeline fluids.
• the solid substrates are any solid substrates that are particulate, which in the case of embedding in the polymer, will embed in the polymer, and in the case of immobilization of the polymer, will allow the polymer to immobilize thereto.
• the solid particle substrates can be hydrophobic or hydrophilic in nature, and can be porous or nonporous and examples of such materials are silica, silica gels, diatomaceous earth, sand, cellulosics, polystyrene beads, clay, and the like.
• the materials that are useful in this invention are materials comprising a carbon dioxide sorbing polymer of at least 5,000 Daltons molecular weight and, a solid particulate material, wherein the carbon dioxide sorbing polymer has the capability of interacting with the hydrate crystals of the polymer matrix.
• One embodiment of this invention is a method of controlling the formation of crystalline hydrates in a fluid system, wherein the method comprises contacting the fluid system with the sorbing composition thereby seeding hydrate crystal growth within the polymer/solid complex and not being able to agglomerate hence anti-agglomerate functionality exists.
• the invention deals with polymeric materials that are dendritic in nature, hyperbranched polyamino polymers, or siliconized versions of these polymers wherein the polymers can be used in any one of several combinations.
• the polymers can be siliconized hyperbranched or dendritic polyamino polymers in solvent solution wherein the siliconization is that obtained by treating the polyamino polymers with reactive silanes, or silicones containing functional groups that will allow the polyamino polymers to combine with them.
• polyamino hyperbranched or dendritic polymers that have solid particles embedded in them, the solid particles being described infra.
• polyamino hyperbranched or dendritic polymers is one in which the polyamino hyperbranched or dendritic polymer is immobilized onto solid particle support, wherein the solid supports are those described infra.
• Still another example is the use of the polyamino hyperbranched or dendritic polymers in a particular solvent solution, and finally, another example is the use of the polyamino hyperbranched or dendritic polymers in an emulsion form.
• Polyamino hyperbranched or dendritic polymers including those that are siliconized, are known in the prior art and there are many publications describing them and the methods for their preparation.
• the polymers disclosed herein are chelating polymers capable of interacting with charged gaseous molecules such as carbon dioxide, by removing the carbon dioxide. More practically, the polymers scavenge for the carbon dioxide and thus, prevent the methane or ethane hydrate structure from forming, since they require carbon dioxide to stabilize their structure.
• “Sorb” or “Sorbing” for purposes of this invention means that the polymers have either absorption or adsorption characteristics.
• the solid substrates useful herein are any solid substrates that are particulate.
• such particles must be capable of embedding in the polymer, and in the case of immobilization of the polymer, will allow the polymer to immobilize thereto.
• the composition is used that requires the particle to be embedded, up to about 80 weight percent of particles, based on the weight of the polymer can be embedded.
• the immobilization of the polymers on the substrate up to about 80% of the polymer can be immobilized on the substrate, based on the weight of the solid substrate.
• the solid particle substrates can be hydrophobic or hydrophilic in nature, and can be porous or nonporous and examples of such materials are silica, silica gels, diatomaceous earth, sand, cellulosics, polystyrene beads, clay, and the like.
• the relative size of the particles is not overly critical and any size from nano size through macro size can be used, with the understanding that smaller particles find a wider application in this invention.
• the silica used was a 15 nm (diameter) nano silica dispersion in toluene at the 50% silica level supplied by hanse chemie AG, Geesthacht, Germany as their product Toluenesol XP 19-1076.
• the polymer was the polyethyleneimine supplied by BASF as their commercial product Lupasol® WF (99% water free), product # 745-8035, with an average molecular weight of 25,000 Daltons.
• the method for producing the hyperbranched polymer grafted onto silica as a dispersion can be found in U.S. Patent Publication 20030183578 A1, published on Oct. 2, 2003.
• the silica was a synthetic, amorphous, untreated fumed silicon dioxide, crystalline free and 0.2 to 0.3 micron diameter supplied from Cabot Corporation as their commercial Cab-O-Sil® M5.
• the polymer is the polyethyleneimine of average molecular weight of 25,000 Daltons supplied by BASF and detailed in Product 1 Supra.
• the finished product consisted of 10% by weight of polymer cross-linked and then chemical embedded onto the silica surface by the process described in U.S. Patent Publication 20030183578 A1 set forth above.
• a standard commercial glass Pasteur pipette was held such that the pipette tip projected 12 cm from the stop bung.
• a drop of water was taken into the pipette by means of capillary suction and the pipette with the stop bung intact was weighed and then cooled for at least 2 hours at ⁇ 20° C. in a refrigerator freezer.
• a 3.5% by weight sodium chloride solution was mixed with tetra hydrofuran in the ratio of 100:25.
• a 50 ml. aliquot of this solution was added to a test tube of about 3 cm diameter and about 15 cm long that was held in a cooling bath at ⁇ 1° C. such that the test tube was immersed in the cooling bath to a depth of about 6 cm.
• the frozen pipette was removed from the refrigerator, wiped rapidly to remove any crystal nuclei from the outside of the pipette in order to obtain standard initial conditions, and immediately immersed to a depth of about 1.5 cm in the 50 ml aliquot of the tetrahydrofuran/water/sodium chloride mixture. It became clear that within a very short period of time of between seconds to a couple of minutes, the tetrahydrofuran hydrates began forming at the glass pipette tube surface.
• the pipette was very carefully removed form the test tube after 60 minutes and the pipette with cork stopper and adhering hydrates were immediately weighed again. The difference in weight was attributed to hydrate crystals.
• the growth rate of the THF hydrate formation in g/h can be calculated from the difference between the initial and final weights, and the time elapsed.
• Example 2 The protocol was identical to that carried out under Example 1, except that 2500 ppm of the corresponding inhibitor was added to the test solution unless stated otherwise.
• the simple evaluation was carried out identically to that set forth in Example 1 above.
• the test thus used the same protocol as above with the hydrate anti-agglomerate additives shown in the table below.
• Examples 2 to 5 correspond to the prior art whereas Examples 6 and 7 relate to the process substrates without hyperbranched polymer coating and Examples 8 through 10 relate to inhibitors designed according to this invention that are silica substrates that have the polymer immobilized on the surface.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Organic Chemistry (AREA)
• Materials Engineering (AREA)
• General Life Sciences & Earth Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• General Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Mechanical Engineering (AREA)
• Solid-Sorbent Or Filter-Aiding Compositions (AREA)
• Compositions Of Macromolecular Compounds (AREA)
• Silicon Compounds (AREA)
• Physical Or Chemical Processes And Apparatus (AREA)

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Citations (5)

• 2004
  • 2004-09-10 WO PCT/US2004/029380 patent/WO2005026291A2/fr active Application Filing
  • 2004-09-10 US US10/569,221 patent/US20060218852A1/en not_active Abandoned

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