The method of transportation of liquefied natural gas

 

The invention relates to pipeline transport. In the method of gas transportation serves the gas in the pipeline at the inlet pressure, which is essentially higher than the gas pressure at the outlet of the pipeline, thus carry out the reduction of the gas temperature as a result of Joule-Thomson caused by pressure drop in the pipe, adjust the inlet pressure to achieve a predetermined pressure at the outlet of the pipeline, szhizhajut gas coming out of the pipeline, to obtain a liquefied gas having a temperature above about -112C and a pressure sufficient for the liquid was at or below the temperature of the beginning of the boil, and additionally transported liquefied natural gas under pressure in a suitable container. In the method of transportation of liquefied natural gas (a) is cooled, at least a portion of the stream rich in methanol gas by pass this part through at least one heat exchanger cooled refrigeration unit with a closed cycle, (b) optionally cool the feed stream by expanding it in the pipeline at lower pressure, (C) szhizhajut cooled gas operations (b)://img.russianpatents.com/chr/176.gif">C and a pressure sufficient for the liquid was at or below the temperature of the beginning of the boil. In the method of reduction of natural gas (the second option) szhizhajut the natural gas stream having a temperature of from about -29With up to approximately -73C and a pressure in the range from about 1380 kPa to about 6895 kPa (a) introducing the natural gas stream under pressure in the first installation phase separation for formation of the first fluid stream and the first stream of steam, (b) regulate the pressure of fluid flow to the pressure approximately equal to the working pressure of the third installation for separation of the phases in the operation (1), (C) serves a fluid stream with regulated pressure in the third installation of phase separation, (d) skip the first steam flow through the first heat exchanger for performing heat of the first steam flow, (e) compress and cool the first steam flow, (f) transmit the compressed first steam flow through the first heat exchanger for further cooling the first stream of steam (g) transmit the compressed steam flow through the second heat exchanger for further cooling the first flow of steam to an even greater extent, (h) expand the flow of PKU phase separation for the formation of the second steam flow and the second fluid flow, (j) return the second steam flow back into the first installation phase separation for re-processing, (k) expanding the second stream of fluid to further reduce pressure and decreasing temperature, (l) serves the second fluid flow in the third installation for phase separation to produce a third stream of steam and the flow of liquid product having a temperature above about -112With and having a pressure sufficient for the liquid was at or below the temperature of the beginning of its boiling point, (m) third pass steam flow through the second heat exchanger for cooling the second heat exchanger and (n) pass the third steam flow through the third heat exchanger, compress the third steam flow until the pressure is approximately equal to the working pressure of the first installation phase separation, cool compressed third steam flow and flow of cooled compressed third steam flow through the third heat exchanger and serves compressed third steam flow in the first installation phase separation for recycling. 3 S. and 17 C.p. f-crystals, 2 ill., table 2.

The technical FIELD TO WHICH the INVENTION RELATES

The present invention relates in General to the SPO is to do the installation for liquefying, which receive liquefied natural gas under pressure intended for further transportation.

BACKGROUND of INVENTION

Due to its ability to complete combustion and ease of use of natural gas has been widely used in recent years. Many sources of natural gas are located in remote areas, at large distances from markets for gas. Sometimes there is a pipeline for transporting the supplied natural gas to market. Despite the fact that the transportation of gas by pipeline is typically quite large distances, it does not create problems in the case when it comes to transport gas only by land. However, in many cases, the source of natural gas is separated from the relevant market large masses of water. In the case when transporting through pipelines, it is impossible to realize, the gas is often processed into liquefied natural gas for transportation to market. Installation for liquefying sometimes located in the place where the source of liquefied natural gas, however, the plants for liquefied natural gas is often placed in the ports from which SIG the gas is the need for large capital investments. Pipelines, installation, used for natural gas liquefaction, and vessels for transportation of liquefied natural gas, are quite expensive. Materials for pipelines can be relatively expensive, and the cost of construction and installation of pipelines can also be high, and, in addition, for the transportation of gas by pipeline necessary compressors for gases and refrigeration units. Liquefaction of natural gas includes some basic systems including gas treatment to remove impurities, plants for the liquefaction, refrigeration, plant and equipment for storage and loading onto vessels. Design, creation and operation of such systems can lead to significant cost increases for transportation of natural gas. These systems can make the transportation of natural gas in some regions of the world economically impractical because of too high costs.

Development of natural gas fields in the Arctic regions, such as gas and oil field in Alaska, creates a special serious problems. It is necessary to consider that the pipelines for transportation of natural gas think Iruka gas at temperatures aboveWith frozen ground, in which a buried pipelines, in the end will thaw, and the resulting settling or heaving of the soil can lead to accidents on the pipeline. Accordingly, preservation of frozen soil or permafrost is a major challenge for those people who build and operate the pipeline, not only to protect the environment, but also to minimize injuries and accidents on pipelines.

Have been proposed various systems of pipelines for transportation of natural gas in Arctic conditions. In U.S. patent No. 4192655 described example of a pipeline system to transport natural gas over long distances in the Arctic areas by pipeline to the plant for liquefaction at the port. In this patent it is proposed to use a pipeline having a number of sections arranged in series, with intermediate compressor stations. The pressure and temperature of the gas at the entrance to each section of the pipeline such that the pressure drop of the gas in each section causes a decrease in the gas temperature and the low temperature gas is used for re-cooling the gas is heated as a result of compression, before he goes on the trail of the PA to 15000 kPa and initial temperature below -10°C. The gas leaving the last section of the pipeline may have a temperature -45,2°C or below. During the process of liquefaction in the installation liquefaction, located at the end of the last pipe section, you can take advantage of this low temperature. From installation liquefaction liquefied gas is pumped into tankers for transport to market.

For transportation to the consumer through the courts require the usual processes for the liquefaction of gas, which receive liquid product temperature is below approximately -156,7°C. as a result, more gas is consumed in the process of removal of CO2, gas liquefaction and re-re-gasification of liquid, thus less gas can be supplied to the consumer in the quality of the product. In addition, when transporting gas to the plants for the liquefaction of ordinary steel pipelines used actually working pressure in conventional pipelines limited pressures in the range of 6895 kPa to 15860 kPa, therefore, you want to use the station re-compression of gas along the pipeline route. Station re-compression consume more fuel, and, passing through them, the gas in drobopro is at a higher temperature compared to the temperature, which would have gas, if re-compression is not required.

In this industry there is a continuing need to improve the way transportation of natural gas, which allows minimizing the amount of equipment required for processing, and the total energy consumption. By decreasing the total cost of transporting natural gas over long distances is possible to increase the amount of gas available for use by consumers.

SUMMARY of the INVENTION

The technical task of the present invention was to create a quick and cheap method of transportation.

This technical problem is solved due to the fact that according to the invention in the method of transportation of liquefied natural gas, rich in methane,

(a) serves the gas in the pipeline at the inlet pressure, which is essentially higher than the gas pressure at the outlet of the pipeline, thus carry out the reduction of the gas temperature as a result of Joule-Thomson caused by pressure drop in the pipeline,

(b) regulate the inlet pressure to achieve a predetermined pressure at the outlet of the pipeline,

(c) szhizhajut gas discharged from truboprom, the liquid was at or below the temperature of the beginning of the boil, and

(d) in addition to transport liquefied natural gas under pressure in a suitable container.

Preferably the gas coming out of the pipeline, has a temperature in the range of from about -29With up to approximately -73C and a pressure in the range from about 3450 kPa to 10340 kPa.

Preferably the temperature of the gas is in the range from about -29With up to about -62C.

Preferably the gas pressure is in the range from 3450 kPa to 4137 kPa.

Preferably before the operation (a) further compresses the gas to a specified pressure and then cooled gas through the refrigeration unit with a closed loop.

Preferably after the operation (b) and before operation (C) further cooling the gas discharged from the pipeline.

Preferably additional cooling includes cooling the exiting gas by means of a refrigeration unit with a closed cycle and the subsequent expansion of the gas cooled using a refrigeration plant with a closed cycle, to reduce the pressure and additionally the speaker of the pipeline, is essentially free of carbon dioxide.

Preferably for liquefaction coming out of the pipeline gas during the operation (s)

(a) introducing the gas discharged from the pipeline, in the first installation phase separation for formation of the first fluid stream and the first stream of steam,

(b) regulating the pressure of fluid flow to the pressure approximately equal to the working pressure of the third installation for separation of the phases of the operation (1),

(c) serves a fluid stream with regulated pressure in the third installation of phase separation,

(d) skip the first steam flow through the first heat exchanger for performing heat of the first steam flow,

(e) compress and cool the first steam flow,

(f) transmit the compressed and cooled first steam flow through the first heat exchanger for further cooling the compressed first stream of steam,

(g) transmit the compressed first stream of steam during the operation (f) through the second heat exchanger for further cooling the first steam flow even more,

(h) expanding the steam flow during the operation (g) to reduce the pressure and decreasing temperature,

(i) serves an extended stream to the second installation phase separation for formation of the second potoky phases to be reprocessed,

(k) expanding the second fluid flow to lower pressure and lower temperature,

(1) serves a second fluid flow in the third installation for phase separation to produce a third stream of steam and the flow of liquid product having a temperature above about -112With and having a pressure sufficient for the liquid was at or below the temperature starts boiling,

(m) third pass steam flow through the second heat exchanger for cooling the second heat exchanger, and

(n) third pass steam flow through the third heat exchanger, compress the third flow of the vapor to a pressure approximately equal to the working pressure of the first installation phase separation, cool compressed third steam flow and flow of cooled compressed third steam flow through the third heat exchanger and serves compressed third steam flow in the first installation phase separation for recycling.

Preferably optionally cooled first stream of steam at operation (s) via indirect heat exchange with water or air.

Preferably optionally after passing the third stream of steam at surgery (n) through the third Teploobmennik steam flow when the operation (s) and pass the allotted steam flow through the second heat exchanger and the third heat exchanger to heat a given steam flow and remove hot allotted steam flow as fuel.

Preferably before the operation (a) further cooling the gas stream coming out of the pipeline.

Preferably, the gas stream contains methane and hydrocarbon components heavier than methane, and wherein prior to operation (a) optionally remove most of the heavier hydrocarbons by fractionation.

Preferably optionally injected into the third steam flow steam pressure resulting from evaporation of liquefied natural gas.

Preferably the steam generated by evaporation under pressure is the pressure above 1723,7 kPa and a temperature above -112C.

The technical problem of the invention is also solved due to the fact that according to the invention in a method of liquefying natural gas, rich in methane, under pressure,

(a) is cooled, at least a portion of the stream rich in methane gas by pass this part through at least one heat exchanger cooled refrigeration unit with a closed cycle,

(b) additionally cool the feed stream by expanding it in the pipeline at lower pressure,

(C) szhizhajut cooled gas operations (b) in the SG is the pressure, sufficient to ensure that the fluid was at or below the temperature of the beginning of the boil.

The technical problem is also solved due to the fact that according to the invention in a method of liquefying natural gas, rich in methane, under pressure, having a temperature of from about -29°C to about -73C and a pressure in the range from about 1380 kPa to about 6895 kPa,

(a) introducing the natural gas stream under pressure in the first installation phase separation for formation of the first fluid stream and the first stream of steam,

(b) regulate the pressure of fluid flow to the pressure approximately equal to the working pressure of the third installation phase separation in subsequent operations (1),

(c) serves a fluid stream with regulated pressure in the third installation of phase separation,

(d) skip the first steam flow through the first heat exchanger for performing heat of the first steam flow,

(e) compress and cool the first steam flow,

(f) transmit the compressed first steam flow through the first heat exchanger for further cooling the compressed first stream of steam,

(g) transmit the compressed steam flow through the second heat exchanger for additional the Oia pressure and decreasing temperature,

(i) serves an extended stream to the second device for separation of the phases for the formation of the second steam flow and the second fluid flow,

(j) return the second steam flow back into the first installation phase separation for recycling,

(k) expanding the second fluid flow to lower pressure and lower temperature,

(l) serves the second fluid flow in the third installation for phase separation to produce a third stream of steam and the flow of liquid product having a temperature above about -112With and having a pressure sufficient for the liquid was at or below the temperature starts boiling,

(m) third pass steam flow through the second heat exchanger for cooling the second heat exchanger, and

(n) third pass steam flow through the third heat exchanger, compress the third steam flow until the pressure is approximately equal to the working pressure of the first installation phase separation, cool compressed third steam flow and flow of cooled compressed third steam flow through the third heat exchanger and serves compressed third steam flow in the first installation phase separation for recycling.

Prepa education of the gas stream and a liquid product, having a temperature of from about -112With up to approximately -73C.

BRIEF DESCRIPTION of DRAWINGS

The present invention and its advantages will be better understood upon studying the following detailed description and the attached figures.

Fig.1 is a schematic diagram of one variant of the method of liquefaction according to the invention.

Fig.2 is a schematic diagram of a second variant of the method of liquefaction according to the invention.

On the figures presented two variants of the method according to the invention. The figures are not intended to exclude from the scope of the invention other embodiments, which are the result of normal and expected modifications of these specific embodiments. Various necessary subsystems, such as valves, control systems, sensors, clamps and the support structure for vertical pipes were removed from the figures for simplicity and clarity of the presented image.

Description of the INVENTION

The present invention represents an improved method of transporting natural gas on a large distance, while now the methane liquid product, having a temperature above about -112C and a pressure sufficient for the liquid product was kept at the temperature of the beginning of its boiling point or at a temperature below the point of boiling. This rich methane product sometimes this description is called liquefied natural gas under pressure. The term “point initial boiling point” refers to the temperature and pressure at which the fluid begins to turn into a gas. For example, if a certain amount of liquefied natural gas under pressure is held at a constant pressure, but the temperature increases, the temperature at which the gas bubbles begin to form in liquefied natural gas under pressure, represents the point at the beginning of the boil. Similarly, if a certain amount of liquefied natural gas under pressure is held at a constant temperature, but the pressure decreases, the pressure at which begins the formation of gas, determines the starting point of boiling. In point initial boiling point of the mixture is a saturated liquid.

The way the gas liquefaction process according to the invention requires less energy to transport gas by pipeline and subsequent size is s, used to implement the method according to this invention, may be made of less expensive materials. On the contrary, the methods according to the preceding technical level, allowing to get normal liquefied natural gas under atmospheric pressure and having a temperature just -160Require the use of technological equipment, made of expensive materials to ensure safe operation. The invention is particularly suitable for use in Arctic conditions, but the invention can also be used in warm climates.

The amount of energy required for the liquefaction of natural gas during the implementation of this invention, significantly less compared to the amount of energy consumed when running a typical installation for liquefying natural gas, which provides reception of liquefied natural gas under atmospheric pressure and having a temperature of approximately -160C. reducing the amount of energy required to produce the necessary artificial cold for the method according to the invention, leads to a significant reduction capitalista significant improvement in economic indicators of the process of obtaining liquefied natural gas.

As shown in Fig. 1, the feed gas, which represents the raw materials and obtained from the reservoir for natural gas, associated gas during oil or from any other source, are fed into the thread 5 in the zone 45 compression, containing one or more compressors. Although this is not shown in Fig. 1, before the filing of the original gas compressors it is usually processed to remove contaminants.

The first factor that should be taken into account when the cryogenic natural gas processing, this pollution. Not subjected to the processing of raw natural gas, which represents a raw material suitable for the method according to the invention may contain natural gas obtained from oil well (associated gas) or from a gas well (the gas obtained from the gas reservoir (inclement)). The composition of natural gas can vary significantly. When using the term “natural gas” in the present description, we are talking about the natural gas stream containing methane (C1) as a main component. Typically, natural gas also contains ethane (C2), higher hydrocarbons (C3+) and minor amounts of contaminants, such as the s impurities, the iron sulfide, wax, and crude oil. The solubility of these contaminants varies with temperature, pressure and composition. At cryogenic temperatures CO2water or other impurities can form solid particles that can clog the channels for flow in cryogenic heat exchangers. These potential difficulties can be avoided by removing contaminants, if it is expected that the conditions for this impurities in pure form, in which the relation between temperature and pressure on the phase boundaries leads to the formation of the solid phase. In the following description, it is assumed that the flow of natural gas fed to the zone 45 compression, subjected to appropriate treatment to eliminate unacceptably high levels of sulfides and carbon dioxide and the dehydration to remove water by the use of traditional and well-known methods to obtain the stream “neutral, deodorized, dehydrated natural gas. If the natural gas stream contains heavy hydrocarbons, which can vymorazhivanija in the process of liquefaction, or if you do not want the presence of heavy uglevodorodyonogo before liquefaction of natural gas. At operating pressures and temperatures of liquefied natural gas under pressure moderate amounts of nitrogen in the natural gas can be valid, because the nitrogen will remain in the liquid phase together with liquefied natural gas under pressure.

After compression in the zone 45 compression of natural gas is preferably passed through the end 46 fridge for cooling of the gas stream through indirect heat exchange before the gas goes into the pipe 47. End refrigerator 46 can be any conventional refrigeration system, which provides cooling natural gas to a temperature below approximately -1,1For those applications in which the pipeline is buried in frozen ground or permafrost. End refrigerator 46 preferably contains a combination of heat exchangers air cooled or water cooled and conventional refrigeration unit with a closed cycle and propane as refrigerant.

Natural gas is compressed by zone 45 compression to a pressure sufficient to obtain a predetermined pressure and temperature at the exit of the pipe (flow 7). Pressure natural gas inlet pipe (PNA, due to the pressure drop in the pipeline. The gas pressure at the entrance to the pipeline can be determined by experts in the field of engineering with regard to the length of the pipeline, gas flow and friction losses occurring during the transportation of gas by pipeline. The pressure of the incoming gas (stream 6) preferably will be in the range of from about 17238 kPa to about 48625 kPa, and more preferably in the range from 20685 kPa to 24133 kPa.

The pipeline material which can serve as alloy steel, preferably provided with insulation, which is designed to ensure that the temperature of the released gas will be lower than the temperature of the incoming gas. Suitable insulating materials are well known to specialists in this field of technology. The metal pipe is preferably a high-strength low-alloy steel with increased resistance to atmospheric corrosion, containing less than about three weight percent Nickel and having a tensile strength and toughness required for the retention of natural gas at operating conditions according to the invention. Examples of steels suitable for use when POPs is buried in the ground or in the seabed, or laid on the ground or the seabed, or raised to a certain height above the ground or seabed, or in the construction of the pipeline can be used any combination of the above methods depending on where the transportation of gas.

The gas pressure at the exit of the pipe (stream 7) is preferably in the range from about 3450 kPa to 10340 kPa, and more preferably in the range from approximately 3790 kPa to 8620 kPa. If the gas pressure at the outlet is below approximately 3450 kPa, the gas pressure can be increased by using the appropriate compression means (not shown), which may contain one or more compressors, which compress the gas to a pressure of not less than 3450 kPa before the gas will enter the plant for liquefaction. The temperature of the natural gas coming out of the pipe 47, is preferably in the range of from about -29C to -73With and, more preferably, in the range of from about -29C to -62C. While the gas coming out of the pipeline, can be entered directly into the installation 54 phase separation, gas, coming out of the pipeline, Priceline is cooled to an even greater extent due to the expansion with decreasing pressure. As shown in Fig.1, the gas coming out of the pipeline, preferably cooled in the chiller 48, which may be in the form of any conventional refrigeration unit with a closed loop, preferably in the form of a refrigeration plant with a closed cycle and propane as a refrigerant, and, more preferably, in the form of a refrigeration plant with a closed loop containing a mixture of C1C2With3With4and C5as the cooling agent. The stream exiting the refrigeration unit 48, is further cooled in the zone 49 extension, which contains a mechanical expander or the throttle valve, or both, in order to achieve a predetermined final pressure and temperature of the outgoing gas. Area 49 of the extension preferably contains one or more turbo-expanders that provide at least partial liquefaction of the gas stream.

Metallurgical properties, diameter and operating pressure of the pipe 47 and the parameters of the source gas (stream 6) is supplied to the pipe 47 can be optimized by experts in the field of technology with the ideas set forth in this description to avoid expensive re SG and temperature in the chiller 48 and in zone 49 extensions can also be optimized by experts in the field of engineering with regard to ideas, set forth in this description in order to fully utilize the cooling cycle Joule-Thomson in the pipe 47 and thereby to obtain the maximum possible volume of gas that can be delivered to consumers.

Natural gas is introduced into the installation 54 for separation of the phases, divided into the thread 13 of the fluid flow 12 a pair. Typically, you will need to regulate the pressure of the flow 13 of the liquid in the zone 70 of the control pressure is a pressure that is approximately equal to the working pressure of the installation of 65 phase separation. In most cases, the use of this invention the pressure of the stream 13 will not be the same as the operating pressure of the installation of 65 phase separation. If the pressure of the stream 13 will be less than the operating pressure of the installation 65 for phase separation zone 70 pressure regulating preferably will contain a pump to increase the pressure of the stream 13 to the value approximately equal to the pressure of the fluid in the installation of 65 phase separation. If the pressure of the stream 13 exceeds the operating pressure of the installation 65 for phase separation zone 70 pressure regulating preferably will contain an expander, such as a hydraulic turbine to reduce the pressure to the pressure Tg 55 compression to increase the pressure of the flow 12. The compression zone preferably contains a heat exchanger 56, through which the thread 12 is heated before serving it as a thread 15, at least two compressor 57 and 59, with at least one heat exchanger 58 is installed between the compressor 57 and 59 and at least one heat exchanger 60 is installed after the last compressor 59. Thread 19 of steam leaving the heat exchanger 60 is passed through the heat exchanger 56 for additional cooling via indirect heat exchange with the incoming stream 12 a pair.

This invention is not limited to any type of heat exchanger, but for economic reasons it is preferable to set the finned plate heat exchangers, heat exchangers, spiral pipes and regenerative chamber heat exchangers, which provide cooling by indirect heat exchange. The term “indirect heat exchange” in the sense in which it is used in this description and the claims, means the bringing of two fluid flows in the condition of heat exchange with each other without any physical contact or mixing a fluid with each other.

From zone 55 compression compressed stream 20 gas passes through the heat exchanger 61, UCC 21 then passes through the zone 62 of the extension, preferably containing one or more hydraulic turbines, to reduce the pressure and temperature of the gas stream and, thereby, for at least partial liquefaction of the gas stream. At least partially liquefied gas (stream 22) is then in the installation 63 phase separation, which ensures the separation of liquid and vapor with the formation of the vapor stream 24 and the thread 23 of the liquid. Part of the vapor stream 24 is returned to the installation of 54 phase separation for recycling. The second part of the thread 24 is given in the form of thread 36 and then passes through the heat exchanger 61 for heating the stream 36. Emerging from the heat exchanger 61 is heated stream (stream 37) is additionally heated by the heat exchanger 67 to receive the heated stream 31, which is used as fuel. This fuel can be used to generate the energy required to actuate the turbine, which partially supply the power to the compressors in the zone 55 compression.

Thread 23 of the liquid formed in the installation of 63 phase separation, served in a different area 64 of the extension is preferably in the form of a hydraulic turbine, to further reduce the pressure and temperature of the fluid flow. Stream 25 from the zone 64 expansion comes satuki, at least part of the energy required for the operation of the compressor 57 and 59.

In the installation of 65 phase separation is formed thread 26 of steam and the flow 27 of the liquid. Thread 27 of the liquid is supplied in an appropriate container, such as a stationary storage tank, or in an appropriate vehicle, such as a ship, barge, underwater ship, railway wagon-tank or truck. In accordance with the practical implementation of the method according to the invention the thread 27 of the liquid will have a temperature above about -112C and a pressure sufficient for the liquid was kept at the temperature of the beginning of its boiling point or at a temperature below the point of boiling.

Thread 26 of the steam flows through the heat exchanger 61 for cooling the stream 20 of steam by indirect heat exchange. Emerging from the heat exchanger 61 stream 29 passes through another heat exchanger 67 and then is compressed by the compressor 68 to a pressure approximately equal to the pressure in the installation 54 to separate the phases. Compressed gas (stream 32) is then cooled in the usual limit the fridge 69 with air or water and then further cooled through heat exchanger 67 before Obyedinennaya.

During storage, transportation and handling operations associated with liquefied natural gas, can produce a significant amount of vapors released during the evaporation, which are formed by evaporation. The method according to the invention in a possible variant, but not the obligation, to provide the liquefaction of such vapors released during the evaporation (boiling). As shown in Fig. 1, a pair of 28 released during the evaporation, is preferably introduced into the liquefaction process by combining them with the thread 26 a pair. Although it is not shown in Fig. 1, pairs, separated by evaporation, preferably introduced into the process pressure equal to the pressure of stream 26.

Although it is not shown in Fig.1, before the introduction of the vapors released during the evaporation, stream 26, as a rule, required or to increase their pressure with a compressor, or to reduce their pressure by means of the expander.

In Fig. 2 shows another variant embodiment of the invention, in which elements having the same numbers as elements in Fig.1 perform the same functions when implementing the method. However, for specialists in the art it is obvious that the technological equipment used to implement the method according to one of iagnostic work at different costs temperatures and fluid compositions. An implementation option in Fig. 2 same as option implementation in Fig. 1 except that the zone 48 and cooling zone 49 of the extension of Fig. 1 are not used in the embodiment of Fig. 2, and in the embodiment of Fig. 2 fuel gas (stream 31) is discharged from the vapor withdrawn from the top of the unit 65 for separation of the phases, while in the embodiment of Fig. 1 fuel gas (stream 31) is discharged from the vapor withdrawn from the top of the unit 63 to separate the phases.

In order to minimize the energy consumed in compressing and necessary for liquefaction in the presence of significant amounts of nitrogen in the stream 5 is supplied a source of natural gas and/or flow 28 vapors released during the evaporation, the nitrogen contained in the natural gas, preferably concentrated and removed at some point in the process. In accordance with the method according to the invention provide concentration of nitrogen in the streams 24 and 26 couple, and the stream 24 pair has a higher concentration of nitrogen compared with stream 26 a pair. In the embodiment of Fig. 1 part of the flow 24 pair away as a fuel gas (stream 31), and in the embodiment of Fig. and mass and energy to illustrate variants of implementation, shown in the figures, and the results are shown below in tables 1 and 2. Table 1 corresponds to a variant implementation, shown in Fig. 1 and table 2 corresponds to a variant implementation, shown in Fig. 2. Values of temperature, pressure and costs presented in the table should not be considered as limitations of the invention, in which you can use different values of temperature and expenses, taking into consideration the idea set forth in this description.

In both simulation experiments, it was assumed that the supply of natural gas is carried out at a distance of 457 km pipeline with a diameter of 21 inches (533,4 mm), which was buried in the permafrost in Alaska. When running the first simulation experiment (table 1) it was assumed that the composition of the gas included 85,9 mol % methane, 13.5 mol % ethane and heavier hydrocarbons, 100 parts of CO2a million and 0.6 mol % of N2. When performing the second simulation experiment (table 2) it was assumed that the composition of the gas consisted of 94.5 mol% methane, 5 mol% ethane and heavier hydrocarbons, 100 parts of CO2a million and 0.5 mol % of N2.

In the first simulation experiment, the inlet pressure in the pipeline (flow pressure 6 providing flow 6 in Fig. 2) taken at 48266 kPa. The optimal solution for the variant of implementation of Fig. 2 in the case when the total cost of labor beprovide system is minimized when the gas supply at the installation under the pressure of 3450 kPa at initial pressure 48266 kPa.

Data were obtained by using a commercially available simulation program processes, called HYSYSsold by Hyprotech Ltd., Calgary, Canada; however, to receive data can be used other commercially available simulation program processes, including, for example, HYSIM, PROIIand ASPEN PLUSthat all well-known specialists in this field of technology.

To a person skilled in the art, in particular for those familiar with the ideas of this application, many obvious modifications and options for implementation specific processes described above. For example, according to the invention can use a variety of temperatures and pressures depending on the design of the facility in General and the composition of the supplied source gas. In addition, the number of units for cooling supplied source gas may be supplemented or reconfigure the heat transfer. As discussed above, the disclosed specific embodiments of, and examples should not be used to limit the scope of the invention which should be determined from the following claims and their

equivalents.

Claims

1. The method of transportation of liquefied natural gas, rich in methane, which

(a) serves the gas in the pipeline at the inlet pressure, which is essentially higher than the gas pressure at the outlet of the pipeline, thus carry out the reduction of the gas temperature as a result of Joule-Thomson caused by pressure drop in the pipeline,

(b) regulate the inlet pressure to achieve a predetermined pressure at the outlet of the pipeline,

(C) szhizhajut gas coming out of the pipeline, to obtain a liquefied gas having a temperature above about -112C, and a pressure sufficient for the liquid was at or below the temperature of the beginning of the boil, and

(d) in addition to transport liquefied natural gas p is, has a temperature of approximately -29...-73C and a pressure of approximately 3450 - 10340 kPa.

3. The method according to p. 2, in which the gas temperature is in the range of approximately -29...-62C.

4. The method according to p. 2, in which the gas pressure is in the range 3450 - 4137 kPa.

5. The method according to p. 1, wherein prior to operation (a) further compresses the gas to a specified pressure and then cooled gas through the refrigeration unit with a closed loop.

6. The method according to p. 1, wherein after the operation (b) and before operation (C) further cooling the gas discharged from the pipeline.

7. The method according to p. 6, in which additional cooling includes cooling the exiting gas by means of a refrigeration unit with a closed cycle and the subsequent expansion of the gas cooled using a refrigeration plant with a closed cycle, to lower pressure and lower temperature.

8. The method according to p. 1, wherein the gas is natural gas.

9. The method according to p. 1, in which the gas coming out of the pipeline, is essentially free of carbon dioxide.

10. The method according to p. 2, in which liquefaction coming out of the pipeline gas during the operation (s)

(a) introducing the gas, wyoga steam flow,

(b) regulating the pressure of fluid flow to the pressure approximately equal to the working pressure of the third installation for separation of the phases of the operation (1),

(C) serves a fluid stream with regulated pressure in the third installation of phase separation,

(d) skip the first steam flow through the first heat exchanger for performing heat of the first steam flow,

(e) compress and cool the first steam flow,

(f) transmit the compressed and cooled first steam flow through the first heat exchanger for further cooling the compressed first stream of steam,

(g) transmit the compressed first stream of steam during the operation (f) through the second heat exchanger for further cooling the first steam flow even more,

(h) expanding the steam flow operations (g) to reduce the pressure and decreasing temperature,

(i) serves an extended stream to the second device for separation of the phases for the formation of the second steam flow and the second fluid flow,

(j) return the second steam flow back into the first installation phase separation for recycling,

(k) expanding the second fluid flow to lower pressure and lower temperature,

(l) serves the second fluid flow in Tretter above about -112With and having a pressure sufficient for the liquid was at or below the temperature starts boiling,

(m) third pass steam flow through the second heat exchanger for cooling the second heat exchanger and

(n) third pass steam flow through the third heat exchanger, compress the third flow of the vapor to a pressure approximately equal to the working pressure of the first installation phase separation, cool compressed third steam flow, pass the cooled compressed third steam flow through the third heat exchanger and serves compressed third steam flow in the first installation phase separation for recycling.

11. The method according to p. 10, which further cooled first stream of steam at operation (s) via indirect heat exchange with water or air.

12. The method according to p. 10, wherein optionally after passing the third stream of steam at surgery (n) through the third heat exchanger divert a portion of the third stream of steam as fuel.

13. The method according to p. 10, which additionally divert a portion of the second steam flow when the operation (s), miss allotted steam flow through the second heat exchanger and the third heat exchanger to heat a given steam flow and remove the additional cool the gas stream, coming out of the pipeline.

15. The method according to p. 10, wherein the gas stream contains methane and hydrocarbon components heavier than methane, and wherein prior to operation (a) optionally remove most of the heavier hydrocarbons by fractionation.

16. The method according to p. 10, which further added to the third steam flow steam pressure resulting from evaporation of liquefied natural gas.

17. The method according to p. 16, in which the steam generated by evaporation under pressure is the pressure above 1723,7 kPa and a temperature above -112C.

18. Method of liquefaction of natural gas, rich in methane, under pressure, in which

(a) is cooled, at least a portion of the stream rich in methane gas by pass this part through at least one heat exchanger cooled refrigeration unit with a closed cycle,

(b) additionally cool the feed stream by expanding it in the pipeline at lower pressure,

(C) szhizhajut cooled gas operations (b) in the plant for liquefaction to obtain a liquefied gas having a temperature above about -112With and davleniya natural gas, rich in methane under pressure having a temperature of approximately -29...-73C and a pressure of approximately 1380 - 6895 kPa, at which

(a) introducing the natural gas stream under pressure in the first installation phase separation for formation of the first fluid stream and the first stream of steam,

(b) regulating the pressure of fluid flow to the pressure approximately equal to the working pressure of the third installation phase separation in subsequent operations (1),

(C) serves a fluid stream with regulated pressure in the third installation of phase separation,

(d) skip the first steam flow through the first heat exchanger for performing heat of the first steam flow,

(e) compress and cool the first steam flow,

(f) transmit the compressed first steam flow through the first heat exchanger for further cooling the compressed first stream of steam,

(g) transmit the compressed steam flow through the second heat exchanger for further cooling the first steam flow even more,

(h) expanding the steam flow operations (g) to reduce the pressure and decreasing temperature,

(i) serves an extended stream to the second device for separation of the phases for the formation of the second steam flow and the I re-processing,

(k) expanding the second fluid flow to lower pressure and lower temperature,

(l) serves the second fluid flow in the third installation for phase separation to produce a third stream of steam and the flow of liquid product having a temperature above about -112With and having a pressure sufficient for the liquid was at or below the temperature starts boiling,

(m) third pass steam flow through the second heat exchanger for cooling the second heat exchanger and

(n) third pass steam flow through the third heat exchanger, compress the third steam flow until the pressure is approximately equal to the working pressure of the first installation phase separation, cool compressed third steam flow, pass the cooled compressed third steam flow through the third heat exchanger and serves compressed third steam flow in the first installation phase separation for recycling.

20. The method according to p. 19, which additionally before surgery (a) expand the flow of gas under pressure to a lower pressure for the formation of a gas stream and a liquid product having a temperature of about -112...-73C.

 

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