EA025641B1 - Method of gas processing - Google Patents

Abstract

A process and an apparatus are disclosed for the recovery of propane, propylene, and heavier hydrocarbon components from a hydrocarbon gas stream in a compact processing assembly. The gas stream is cooled, expanded to lower pressure, and supplied as the bottom feed to an absorbing means inside the processing assembly. A first distillation liquid stream is collected from the lower region of the absorbing means and supplied as the top feed to a mass transfer means inside the processing assembly. A first distillation vapor stream is collected from the upper region of the mass transfer means and cooled sufficiently to at least partially condense it, forming a residual vapor stream and a condensed stream. The condensed stream is supplied as the top feed to the absorbing means. A second distillation vapor stream is collected from the upper region of the absorbing means and directed into one or more heat exchange means inside the processing assembly to heat it while cooling the first distillation vapor stream. The heated second distillation vapor stream is combined with any of the residual vapor stream and the combined stream is directed into the one or more heat exchange means inside the processing assembly to heat it while cooling the gas stream. A second distillation liquid stream is collected from the lower region of the mass transfer means and directed into a heat and mass transfer means inside the processing assembly to heat it, an then the heated combined wapor stream is removed from said processing assembly as a volatile residual gas fraction. The quantities and temperatures of the feeds to the absorbing means are maintained sufficient in the upper region of the absorbing means to recover the desired components in the stripped second distillation liquid stream.

Description

The invention relates to methods and devices for the separation of gas-containing hydrocarbons. Applicants claim priority under chapter 35, sect. 119 (e) of U.S. Provisional Patent Application No. 61/186361, filed June 11, 2009. Applicants also claim priority under chapter 35, sect. 120 of US Law on Additional Patent Application US No. 12/717394, filed March 4, 2010, and Additional Patent Application US No. 12/372604, filed February 17, 2009. Assignees δ.Μ.Ε. The Coffin! 8 bp and Θτίΐοίϊ Epsheegk, Yb. were parties to a collaborative research agreement that entered into force before the invention was created.

Propylene, propane and / or heavier hydrocarbons can be recovered from a variety of gases, such as natural gas, refinery gas, and synthetic gas streams derived from other hydrocarbon materials such as coal, crude oil, naphtha, oil shale, tar sand and lignite. Natural gas usually contains large quantities of methane and ethane, i.e. the total content of methane and ethane in a molar ratio is at least 50% of the gas. The gas also contains comparatively smaller amounts of heavier hydrocarbons, such as, for example, propane, butanes and pentanes, as well as hydrogen, nitrogen, carbon dioxide and some other gases.

The present invention generally relates to the recovery of propylene, propane and heavier hydrocarbons from streams of such gases. The analysis shows that usually the gas stream processed by the proposed method contains in a molar ratio about 88.4% methane, 6.2% ethane and other C ₂ components, 2.6% propane and other C ₃ components, 0 , 3% isobutane, 0.6% normal butane and 0.8% pentanes and heavier hydrocarbons, and the rest is nitrogen and carbon dioxide. Sulfur-containing gases are sometimes present.

The observed cyclical fluctuations in the prices of both natural gas and natural gas condensate at times weakened the growing interest in propane, propylene and heavier components as liquefied products. This has created a demand for methods that could provide more efficient extraction of these substances, and for methods that could ensure their effective extraction with lower capital investment. Known methods suitable for the allocation of these substances, including methods based on cooling and refrigeration of the gas, absorption by oil and absorption by chilled oil. In addition, cryogenic methods have become widespread due to the availability of cost-effective equipment that releases energy when the processed gas expands and simultaneously gives off heat. Depending on the pressure in the gas source, the content of ethane, ethylene and heavier hydrocarbons and the desired end products, any of these methods or a combination of these methods can be used.

For the extraction of components from liquefied natural gas, it is currently generally preferred to use the cryogenic expansion method, since it provides maximum simplicity with easy start-up, operational flexibility, good efficiency, safety and good reliability. Suitable methods are described in US Pat. Nos. 3292380; 4,061,481; 4,140,504; 4,157,904; 4,171,964; 4,185,978; 4,251,249; 4,278,457; 4,519,824; 4,617,039; 4,687,499; 4,689,063; 4,690,702; 4,854,955; 4,869,740; 4,889,545; 5,275,005; 5,555,748; 5,566,554; 5,568,737; 5771712; 5,799,507; 5,881,569; 5,890,378; 5,983,664; 6182469; 6,578,379; 6,712,880; 6,915,662; 7191617; 7,219,513; reissued US patent No. 33.408 and simultaneously pending applications No. 11/430412; 11/839693; 11/971491 and 12/206230; (although the description of the present invention in some cases is carried out for other processing conditions that differ from the conditions described in the listed US patents).

In a typical method for recovering substances by cryogenic expansion, the compressed gas feed stream is cooled by heat exchange with other flows of this method and / or external cooling sources such as a propane compression cooling system. Upon cooling, the gas condenses, and the liquid is collected in one or more separators in the form of high-pressure liquids containing some of the required C ₃ + components. Depending on the content of these components in the gas and the amount of liquids formed, the high-pressure liquids can be expanded to a lower pressure and fractionated. Evaporation occurring during expansion of liquids leads to further cooling of the stream. In some cases, it is desirable to subject the high-pressure fluids to expansion prior to expansion to lower the temperature to which the fluids cool as a result of the expansion. After expansion, the stream, which is a mixture of liquid and steam, is subjected to fractionation in a distillation column (deethanizer). In this column, the expansionary streams after cooling are subjected to distillation to separate the residues of methane, C2 components, nitrogen and other volatile gases in the form of an overhead from the desired C3 components and heavier hydrocarbons forming the lower liquid overhead.

If the feed gas does not completely condense (as is usually the case), the steam remaining after partial condensation can be passed through the expander or through an expansion valve to lower the pressure to a level at which additional liquid condenses as a result of further cooling of the stream. After expansion, the flow enters the absorption section of the column and is in contact with cold liquids, absorbing C ₃ components and heavier

- 1,025,641 components from the vapor phase subjected to expansion flow. From the absorption section of the liquid column, they enter the deethanization section.

The distillation steam stream is discharged from the upper region of the deethanization section and is cooled by heat exchange with the overhead stream from the absorption section, which leads to condensation of at least a portion of the distillation vapor stream. The condensed liquid is separated from the chilled distillation vapor stream, forming a chilled liquid reflux stream, which is directed to the lower region of the absorption section, where the chilled liquids can come into contact with a portion of the vapor subjected to expansion of the stream, as described previously. Part of the stream of chilled distillation steam (if any) and the overhead from the absorption section are combined to form a gas containing residues of methane and C ₂ components.

The separation that occurs during this method (the formation of residual gas removed from the method, which contains almost all methane and C ₂ components contained in the feed gas and almost does not contain C ₃ components and heavier hydrocarbons, and the lower deethanizer a unit which contains almost all C ₃ components and heavier hydrocarbons and contains almost no methane, C ₂ components or more volatile components) consumes energy for cooling the feed gas, for re-evaporation in deethanization section, to reflux the absorption section and / or to re-compress the residual gas.

The present invention uses new means to more efficiently perform the various steps described above and to use less expensive equipment. It is possible to achieve this by combining what was a separate equipment into a single installation, and thereby reducing the size of the site occupied by the processing plant, and reducing the capital costs of its construction. To their surprise, the applicants found that in a more compact installation, the energy consumption required to achieve a given level of extraction is reduced, and thereby the efficiency of the method is increased and operating costs are reduced. In addition, for a more compact installation, you need much less pipes used to connect individual pieces of equipment in a single installation, which further reduces capital costs and eliminates the need for flange pipe connections. And since pipe flanges are potential sources of hydrocarbon leakage (which are volatile organic compounds that cause the greenhouse effect and may be precursors of atmospheric ozone formation), their exclusion reduces the likelihood of their release into the atmosphere and their environmental pollution.

It turned out that in accordance with the present invention, it is possible to achieve a degree of extraction of C ₃ components of more than 99.6% and at the same time to ensure almost complete removal of C ₂ components in the residual gas stream. In addition, at the same recovery level, the present invention provides an almost 100% separation of C ₂ components and lighter components from C ₃ components and heavier components with lower energy consumption than known methods. The present invention, although it can be used at lower pressures and higher temperatures, is mainly used for processing the feed gas in the absolute pressure range from 2.758 to 10.342 kPa (a) under conditions requiring support in the overhead column for extraction from liquefied natural gas temperature not higher than -46 ° C.

For a better understanding of the essence of the present invention, further description is given on examples of its implementation with reference to the accompanying drawings.

In FIG. 1 is a block diagram of a known plant for processing natural gas according to US Pat. No. 5,799,507;

in FIG. 2 is a block diagram of a plant for processing natural gas according to the present invention; in FIG. 3-13 are block diagrams of an alternative use of the present invention for separating a natural gas stream.

When describing the settings shown in the drawings, tables are used that contain flow rates calculated for the characteristic conditions of the method. In the tables below, for convenience, the flow rates (expressed in mol / h) were rounded to the nearest integer. The total flow rates given in the tables are calculated taking into account all non-hydrocarbon components and therefore have higher values than the sum of the flow rates of hydrocarbon components. Temperatures are rounded to the nearest integer. It should also be noted that the technological calculations carried out in order to compare the methods presented in the drawings are based on the assumption that there are no heat leaks from the environment to the technological environment (or to the environment from the technological environment). The number of commercially available insulating materials makes this assumption quite reasonable, and it is usually used by specialists in this field.

For convenience, the values of the parameters of the method are given both in British units of measurement and units of measurement of the SI system (In the translation of the text, only the values in units of measurement of the SI system are left - approx. Per.). The molar flow rates given in the table can be expressed either in pound moles per hour or kilogram moles per hour. Energy consumption, expressed in horsepower (HP) and / or thousands of British thermal units per hour (MWt / Ng), refers to the established molar rate of 2,025,641 expressed in pound moles per hour. Energy consumption expressed in kilowatts (kW). refers to the established molar rate, expressed in kilogram moles per hour.

Description of known technical solutions

In FIG. 1 is a flowchart showing the construction of a process unit for extracting C ₃ ⁺ components from natural gas in a known manner according to US Pat. No. 5,799,507. In this model of the method, gas having a temperature of 43 ° C. and a pressure of 6.100 kPa a), in the form of a stream 31. If the content of sulfur compounds in the incoming gas exceeds the permissible value, they are removed by appropriate preliminary processing of the supplied gas (not shown in the drawing). In addition, the feed stream is usually drained to prevent the formation of hydrate (ice) under cryogenic conditions. A solid dehumidifier was usually used for this purpose.

The feed stream 31 is cooled in the heat exchanger 10 with cold residual gas (stream 44), subjected to instant expansion by separator liquids (stream 35a) and distillation liquids having a temperature of -76 ° C (stream 43). The cooled stream 31a, having a temperature of -36 ° C and an absolute pressure of 6.031 kPa (a), enters the separator 11, where the vapor (stream 34) is separated from the condensed liquid (stream 35). The separator liquid (stream 35) expands to a pressure slightly higher than the working pressure (about 2.583 kPa (a)) of the fraction column 15 in the expansion valve 12, cooling the stream 35a to a temperature of -54 ° C. The stream 35a enters the heat exchanger 10, cools the feed gas, as described above, is heated to 41 ° C, creating a stream 35b before entering the fractional column 15 through the loading pipe below the middle of the column.

Steam (stream 34) from the separator 11 enters the expander 13, in which mechanical energy is extracted from this part of the supplied gas, which is the high-pressure floor. In the expander 13, the vapor undergoes adiabatic expansion to a working pressure in the fraction column 15 and cools during expansion, forming a stream 34a subjected to expansion, having a temperature of about -74 ° C. Commercially available expanders are capable of extracting about 80-85% of the work theoretically available with perfect adiabatic expansion. The work performed is often used to drive a centrifugal compressor (such as 14), which can be used, for example, to re-compress the heated residual gas (stream 44a). Partially condensed during expansion, stream 34a is then loaded into fractional column 15 through a feed pipe above the middle of the column.

The deethanizer in column 15 is a conventional distillation column containing a plurality of plates arranged one above the other, one or more nozzles, or some combination of plates and nozzles. The deethanizer column consists of two sections: the upper absorption (distillation) section 15a, which contains plates and / or nozzles, to provide the necessary contact between the vapor subjected to expansion of the flow 34a, rising up, and the cooled liquid flowing down to allow condensation and absorption of C3 -components and heavier hydrocarbons; and a lower stripping section 15b, which contains plates and / or nozzles, to provide the necessary contact between liquids flowing down and vapors rising up. The deethanizer section 15b also contains at least one additional evaporator (such as additional evaporator 16), which heats and evaporates a part of the liquids flowing down to ensure the desorption of vapors that rise up the column, stripping the liquid products, stream 37, from methane, With ₂ components and lighter hydrocarbons. The stream 34 enters the deethanizer 15 through the loading nozzle in the middle of the column, located at the lower part of the absorption section 15a of the deethanizer 15. The liquid part of the expanded stream 34a is mixed with the liquids flowing down from the absorption column 15a, and enters with them into the stripping section 15b deethanizer 15. The vapor portion of the expanded stream 34a rises through the absorption section 15a and is in contact with the cold liquid flowing down to condense and absorb the C3 component Options and heavier hydrocarbons.

Part of the distillation vapor (stream 38) is removed from the upper region of the stripping section 15b. Then this stream is cooled and partially condensed (stream 38a) in the heat exchanger 17 by heat exchange with a cold overhead 36 of a deethanizer, which has a temperature of -79 ° C at the outlet of the deethanizer 15. The cold overhead of the deethanizer is heated to about −66 ° C. (stream 36a), cooling stream 38 from −35 to −75 ° C. (stream 38a).

The operating pressure in the separator 18 with a reflux condenser is slightly lower than the working pressure in the deethanizer 15. This pressure difference serves as a driving force forcing the flow of distillation steam 38 to flow through the heat exchanger 17 into the separator with the reflux condenser 18, in which the condensed liquid (stream 40) is separated from the non-condensed vapor ( stream 39). The non-condensing vapor stream 39 merges with the heated overhead stream 36a of the deethanizer from the heat exchanger 17, forming a cold residual gas stream 44 having a temperature of -38 ° C.

The liquid stream 40 from the separator 18 with a reflux condenser is pumped by the pump 19 under a pressure that is slightly higher than the working pressure in the deethanizer 15. The pumped stream 40a is then divided into two parts. One part (stream 41) is supplied as cold reflux to the upper absorption region

- 3 025641 of the column 15a of the deethanizer 15. This cold liquid has an absorption-cooling effect inside the absorption (distillation) section 15a of the deethanizer 15, in which the saturation of the rising vapors due to the evaporation of methane and ethane contained in stream 41 provides cooling of this section. Note that, as a result, the steam leaving the upper region (overhead 36) flowing from the lower liquid region (distillation liquid stream 43) of the absorption section 15a has a lower temperature than any of the streams loaded into the absorption section 15a ( streams 41 and stream 34a). This absorption-cooling action allows the overhead of the column (stream 36) to provide sufficient cooling in the heat exchanger 17 so that a partial condensation of the distillation vapor stream (stream 38) occurs, even if the stripping section 15b does not operate at a pressure significantly higher than the pressure in the absorption section 15a. This absorption-cooling effect also helps the reflux stream 41 to condense and absorb the C ₃ components and heavier hydrocarbons from the distillation vapor rising upstream of the absorption section 15 a. The other part (stream 42) of the evacuated stream 40a is fed to the upper region of the stripping section 15b of the deethanizer 15, in which the cold liquid acts as reflux, absorbing and condensing the C ₃ components and heavier hydrocarbons coming from the bottom up, so that the distillation vapor stream 38 contains minimum amounts of these compounds.

The distillation fluid stream 43 is removed from the deethanizer 15 at the bottom of the absorption section 15a and sent to a heat exchanger 10, where it is heated to cool the feed gas, as previously indicated. Typically, the flow of this fluid comes from the deethanizer by circulation through a thermosiphon, but you can use a pump. The liquid stream is heated to -20 ° C, partially evaporating before the stream 43a returns to the deethanizer 15 through the loading nozzle in the middle of the column located in the middle region of the stripping section 15b.

In the stripping section 15b of the deethanizer 15, the charged streams are stripped from the methane and C ₂ components. Stream 37 of the resulting liquid leaves the bottom of the column at a temperature of 94 ° C according to the calculation for a typical ethane: propane ratio of 0.048: 1, with a molar expression of the composition of the lower overhead. Cold residual gas (stream 44) flows countercurrent to the feed gas in the heat exchanger 10, where it is heated to 37 ° C (stream 44a). The residual gas is then recompressed in two stages. In the first stage, the compressor 14 is driven by the expander 13. In the second stage, the compressor 20 is driven by an additional energy source and compresses the residual gas (stream 44c) to a pressure in the consumer network. After cooling to a temperature of 49 ° C in the exhaust cooler 21, the residual gas stream 44B enters the consumer gas pipeline at an absolute pressure of 6.307 kPa (a), satisfying the requirements for gas pipelines (usually with respect to the inlet pressure).

The list of flow rates and energy consumption for the method depicted in FIG. 1 is shown in the following table.

Table 1. List of flow rates expressed in lb mol / h [kg mol / h]

Flow Methane Ethane Propane Bhutans + Total 31 19419 1355 565 387 21961 34 18742 1149 360 98 20573 35 677 206 205 289 1388 36 18400 1242 3 0 19869 38 2759 1758 fifteen 0 4602 39 1019 86 0 0 1116 40 1740 1672 fifteen 0 3486 41 1044 1003 nine 0 2092 42 696 669 6 0 1394 43 1388 911 365 98 2796 44 19419 1328 3 0 20985 37 0 27 5 62 387 976

Extraction rates *

Propane 99.56%

Butane T 100.00%

Power consumption

Residual gas compression 16,223 kW

Column irrigation pump 31 kW

A total of 16,254 kW * Calculation was made using non-rounded flow rates.

- 4 025641

Description of the invention

In FIG. 2 shows a flow diagram of a method according to the present invention. The composition and condition of the feed gas processed using the method of FIG. 2, the same as in the case of processing in a known manner. Accordingly, the method of FIG. 2 can be compared with the method in FIG. 1 to identify the advantages of the present invention.

In FIG. 2, the feed gas enters the unit in the form of stream 31 and enters the heat exchanger of the inlet cooling section 115a inside the processing unit 115. The heat exchanger may be a finned tube heat exchanger, a plate heat exchanger, a heat exchanger with aluminum brazed plates, or another type of heat exchanger, including multi-pass and / or multi-service heat exchangers. The heat exchanger device is configured to provide heat exchange between the stream 31 flowing along one passage of the heat exchanger and the separator fluids that have undergone instant expansion (stream 35a) and the residual gas stream from the condensation section 115b inside the processing unit 115. When heated, the separator fluids have undergone expansion stream 31 is cooled. One part (stream 32) of stream 31 is removed from the heat exchanger after partially cooling stream 31 to a temperature of -4 ° C, and the rest (stream 33) is further cooled so that it exits the heat exchanger at -29 ° C.

The separator section 115e has a head or other device separating it from the deethanizer section 115B, so that both sections inside the processing unit 115 can operate under different pressures. The first part (stream 32) of stream 31 enters the lower region of the separator section 115e at an absolute pressure of 6.031 kPa (a), where the condensed liquid is separated from the steam before the vapor enters the head and mass transfer device inside the separator section 115e. This heat and mass transfer device may also be a finned tube heat exchanger, a plate heat exchanger, a heat exchanger with aluminum brazed plates, or another type of heat exchanger, including multi-pass and / or multi-service heat exchangers. This heat and mass transfer device is configured to provide heat exchange between the steam portion of the stream 32 flowing upstream of one passage of the heat and mass transfer device and the stream of distillation liquid 43 from the absorption section 115c inside the processing unit 115, as a result of which the steam is cooled by heating the stream of distillation liquid. During cooling, the steam can partially condense, the condensate flows down, and the rest of the steam continues to rise upward through the head and heat and mass transfer device. The heat and mass transfer device provides continuous contact between the condensed liquid and the vapor, so that it acts, providing mass transfer between the vapor and liquid phases and partial rectification of the vapor.

The second part (stream 33) of the stream 31 enters the separator section 115e inside the processing unit 115 above the heat and mass transfer device. The condensed liquid is separated from the vapor and mixed with the liquid, which condenses from the vapor part of the stream 32, rising up through the heat and mass transfer device. The vapor part of the stream 33 combines with the steam leaving the heat and mass transfer device, forming a stream 34, which leaves the separator section 115e at a temperature of -35 ° C. The liquid parts (if any) of the streams 32 and 33 and the liquid condensed from the vapor part of the stream 32 into heat and mass transfer devices are combined to form a stream 35, which leaves the separator section 115e at a temperature of -26 ° C. It expands to a pressure slightly higher than the absolute working pressure (about 2.639 kPa (a)) of the deethanizer section 115B inside the processing unit 115, in the expansion valve 12, cooling the stream 35a to a temperature of -41 ° C. Stream 35 enters the heat exchanger of the feed gas cooling section 115a, cooling the feed gas, as described above, and heating the stream 35b to a temperature of 39 ° C before feeding it to the deethanizer section 115B inside processing unit 115 through the feed pipe below the middle of the column .

Steam (stream 34) from the separator section 115e enters the expander 13, in which mechanical energy is extracted from this part of the high-pressure feed. The expander 13 expands the steam under adiabatic conditions to a working absolute pressure (about 2.618 kPa (a)) of the absorption section 115c, cooling the expanded stream 34a to a temperature of about -72 ° C. Thereafter, the partially condensed expanded stream 34a is supplied as feed to the lower part of the absorption section 115c inside the processing unit 115.

The absorption section 115c comprises an absorption device consisting of a plurality of plates arranged one above the other, one or more nozzles, or some combination of plates and nozzles. Trays and / or nozzles in the absorption section 115c provide proper contact between the vapor floating up and the cold liquid flowing down. The vapor portion of the expanded stream 34a floats upward through the absorption device in the absorption section 115c, in contact with a flowing cold liquid, condensing and absorbing C ₃ components and heavier hydrocarbons from these vapors. The liquid portion of the expanded stream 34a is mixed with liquids draining from the absorption device in the absorption section 115c, forming a stream of distillation liquid 43, which is discharged from the lower region of the absorption section 115c at a temperature

- 5,025,641

-74 ° C. The distillation liquid is heated to a temperature of −23 ° C. to cool the vapor portion of stream 32 in the separator section 115e, as described previously, and then the heated distillation liquid stream 43a is supplied to the deethanizer section 1156 inside the processing unit 115 through the feed pipe above the middle of the column. Typically, the flow of this liquid from the absorption section 115c through the heat and mass transfer device and in the separator section 115e enters the deethanizer section 1156 through a thermosiphon, but a pump can also be used.

The absorption section 115c has an internal head or other device for separating it from the deethanizer section 1156, so that both of these sections inside the processing unit 115 can operate in such a way that the pressure in the deethanizer section 1156 is slightly higher than the pressure in the absorption section 115c. This pressure differential serves as a driving force forcing the first distillation steam stream (stream 38) to exit the upper region of the deethanizer section 1156 and enter the heat exchanger in the condensation section 115b inside the processing unit 115. This heat exchanger can also be a finned plate heat exchanger. a heat exchanger, a heat exchanger with aluminum brazed plates, or another type of heat exchanger, including multi-pass and / or multi-service heat exchangers. This heat exchanger is configured to provide heat exchange between a first distillation steam stream 38 flowing in one pass of the heat exchanger and a second distillation steam stream emerging from the absorption section 115c inside the processing unit 115. The second distillation steam stream is heated, subject to cooling and partial condensation stream 38, which then leaves the heat exchanger and is separated into vapor and liquid phases. The vapor phase (if any) is combined with the heated second distillation vapor stream exiting the heat exchanger, forming a residual gas stream that provides cooling of the feed in the cooling section of the feed gas 115a, as described above. The liquid phase is divided into two parts, streams 41 and 42.

The first part (stream 41) is supplied as cold reflux to the upper region of the absorption section 115c inside the processing unit 115 by gravity. This cold liquid has an absorption-cooling effect inside the absorption (distillation) section 115a, in which the saturation of vapors floating through the column by evaporation of the liquid methane and ethane contained in stream 41 provides rectification in this section. This absorption-cooling action allows the second distillation steam stream to provide the cooling necessary for partial condensation of the first distillation vapor stream (stream 38) in the heat exchanger of the condensation section 115b, even if the deethanizer section 1156 does not operate at a pressure significantly higher than the pressure in the absorption section 115c. This absorption-cooling effect also helps the reflux stream 41 to condense and absorb C ₃ components and heavier hydrocarbons from the distillation vapor rising upstream of the absorption section 115c. The second part (stream 42) of the liquid phase separated in the absorption section 115b is supplied as cold phlegm to the upper region of the deethanizer section 1156 inside the processing unit 115 by gravity, so that the cold liquid acts as phlegm, absorbing and condensing the C ₃ components and heavier hydrocarbons coming from the bottom up, so that the stream 38 of distillation steam contains minimal amounts of these compounds.

The deethanizer section 1156 inside the processing unit 115 comprises a mass transfer device comprising a plurality of plates arranged one above the other, one or more nozzles, or some combination of plates and nozzles. Trays and / or nozzles in the deethanizer section 1156 provide proper contact between the vapor floating up and the cold liquid flowing down. The deethanizer section 1156 also contains a heat and mass transfer device under the mass transfer device. This heat and mass transfer device can also be a finned tube heat exchanger, a plate heat exchanger, a heat exchanger with aluminum brazed plates, or another type of heat exchanger, including multi-pass and / or multi-service heat exchangers. This heat and mass transfer device is configured to provide heat transfer between the heat carrier flowing in one pass of the heat and mass transfer device and a stream of distillation liquid flowing down from the heat and mass transfer device in the deethanizer section 1156, so that the distillation liquid stream is heated. When the flow of distillation liquid is heated, part of it evaporates, forming a pair of light fractions that floats up, while the rest of the liquid continues to flow down through the heat and mass transfer device. This heat and mass transfer device provides continuous contact between the vapor of light fractions and the flow of distillation liquid, so that it also provides mass transfer between the vapor and liquid phases, stripping the liquid stream 37 from methane, C ₂ components and lighter components. The resulting liquid product (stream 37) leaves the lower region of the deethanizer section 1156 and is removed from the processing unit 115 at a temperature of 95 ° C.

A second distillation vapor stream emerging from the absorption section 115c is heated in the condensation section 115b, cooling stream 38, as previously described. The heated second distillation steam stream is combined with the steam separated from the cooled first distillation vapor stream 38 025641 38, as described above. The resulting residual gas stream is heated in the cooling section of the feed gas 115a, cooling the stream 31, as described above, and then the residual gas stream 44 is removed from the processing unit 115 at a temperature of 40 ° C. Then, the residual gas stream is subjected to re-compression in two stages, by a compressor 14 driven by an expander 13 and a compressor 20 driven by an additional energy source. After cooling to a temperature of 49 ° C in the outlet cooler 21, the residual gas stream 44c enters the consumer gas pipeline at an absolute pressure of 6.307 kPa (a), satisfying the requirements for gas pipelines (usually with respect to the inlet pressure).

The list of flow rates and energy consumption for the method depicted in FIG. 2 is shown in the following table.

Table 2. List of flow rates expressed in lb mol / h [kg mol / h]

Flow Methane Ethane Propane Bhutans + Total 31 19419 1355 565 387 21961 32 4855 339 141 97 5490 33 14564 1016 424 290 16471 34 18870 1135 348 104 20683 35 549 220 217 283 1278 38 2398 1544 thirteen 0 4015 41 1018 868 8 0 1924 42 737 628 5 0 1394 43 1112 723 353 104 2320 44 19419 1328 3 0 20984 37 0 27 5 62 387 977

Extraction rates *

Propane 99.63%

Bhutanes + 100,001

Power consumption

Compression of residual gas 9.633 kW * Calculation is made using non-rounded values of flow rates.

Comparison of the table. 1 and 2 shows that the present invention provides the same degrees of recovery as the known method. However, further comparison of the table. 1 and 2 shows that the product yield was achieved by consuming significantly less energy than by the known method. From the point of view of extraction efficiency (determined by the amount of propane recalculated per unit of energy), the present invention provides a more than 5% increase in comparison with the known method in FIG. one.

The increase in extraction efficiency provided by the present invention compared to the known method of FIG. 1 is due mainly to three factors.

Firstly, the compact arrangement of the heat exchanger in the cooling section of the feed gas 115a and in the condensation section 115b of the processing unit 115 eliminates the pressure drop in the connecting pipes available in conventional processing plants. As a result, the residual gas enters the compressor 14 at a higher pressure than in the known method, and thereby reduces the energy consumption for compressing the residual gas in order to equalize its pressure with the pressure in the gas pipeline.

Secondly, the use of heat and mass transfer device in the deethanizer section 1156 provides simultaneous heating of the distillation liquid exiting the mass transfer device in the deethanizer section 1156, allowing the vapors to come into contact with the liquid and to vaporize volatile components, and is more efficient than using a conventional distillation column with external reboilers . Volatile components are steamed from the liquid continuously, lowering the concentration of volatile components in the vapor faster and thereby increasing the efficiency of the steaming in the proposed method.

Thirdly, the heat and mass transfer device in the separator section 115e, while simultaneously cooling the vapor part of the stream 32 and condensing the heavier hydrocarbons from the steam, provides a partial rectification of the stream 34 before its subsequent expansion and supply as a raw material to the absorption section 115c. As a result, for rectification of the expanded stream 34a in order to remove the C ₃ components and heavier hydrocarbons from it, a lower reflux stream (stream 41) is required, as shown by a comparison of the flow rates 41 in Table. 1 and 2.

The present invention provides two more advantages over the known method, in addition to increasing extraction efficiency. Firstly, the compact arrangement of the processing unit 115 in the proposed method allows you to replace six separate pieces of equipment in the known method (heat exchangers 10 and 17, the separator 11, the separator with reflux condenser 18, an irrigation pump

- 7,025,641 columns 19 and fractional column 15 in FIG. 1) per unit of equipment (processing plant 115 in Fig. 2). This reduces the size of the area occupied by the equipment, eliminates the connecting pipes and reduces the energy consumption of the pump for irrigation of the column, thereby reducing capital costs and operating costs of the technological installation using the proposed method, compared with the known installations. Secondly, the elimination of connecting pipes leads to a significant reduction in the number of flange connections at the installation using the proposed method, in comparison with known installations, which reduces the number of potential sources of leakage at the installation. Hydrocarbons are volatile organic compounds, and some of them are considered to cause a greenhouse effect, while others may be precursors to the formation of atmospheric ozone, so the present invention reduces the amount of atmospheric emissions that can harm the environment.

Other embodiments of the invention.

As previously indicated for the exemplary embodiment of the present invention depicted in FIG. 2, the first distillation vapor stream 38 partially condenses, and the condensate formed is used to absorb valuable C ₃ components and heavier hydrocarbons from the vapors exiting the expander. However, the present invention is not limited to this embodiment. For example, it may be better to treat in this way only part of the steam leaving the expander, or use only part of the condensate as absorbent in cases where, for other design reasons, part of the steam from the expander or part of the condensate should pass the absorption section 115c of the processing unit 115. The state of the gas loaded, the size of the installation, the availability of equipment and other factors can show when to do without expander 13 or replace it with another expansion device property (such as an expansion valve), or when it is possible or prefer to carry out full (rather than partial) condensation of the first distillation vapor stream 38 in the condensation section 115b inside the processing unit 115. It should also be noted that depending on the composition of the feed gas stream, it is preferable to use an external refrigerator to provide partial cooling of the first stream of distillation vapor 38 in the condensation section 115b.

In some cases, it may be preferable to use an external separator vessel for separating the cooled first and second parts 32 and 33 or the cooled feed stream 31a rather than including the separator section 115e in the processing unit 115. As shown in FIG. 8, a heat and mass transfer device in the separator 11 can be used to separate the first and second parts 32 and 33 into a vapor stream 34 and a liquid stream. Similarly, as shown in FIG. 9-13, a separator 11 may be used to separate the cooled feed stream 31a into a vapor stream 34 and a liquid stream 35.

The use and distribution of the liquid stream 35 from the separator section 115e or the separator 11 and the distribution of the liquid stream 43 from the absorption section 115c to provide process heat transfer, the specific location of the heat exchangers for cooling the feed gas (streams 31 and / or 32) and the first distillation vapor stream 38, selection process flows for certain heat exchanges should be made individually in each case. For example, in FIG. 4-6 and 10-12, the distillation liquid stream 43 is partially used to cool the first distillation vapor stream 38 in the condensation section 115b (FIGS. 4, 5, 10 and 11), the heat exchanger 10 (FIGS. 6 and 12). In such cases, the heat and mass transfer device in the separator section 115e (Fig. 4-6) or the separator 11 (Fig. 10-12) may be unnecessary. In the embodiment shown in FIG. 4 and 10, pump 22 is used to supply a stream of distillation liquid 43 to a heat exchanger in the condensation section 115b. In the embodiment shown in FIG. 5 and 11, the condensation section 115b is located in the processing unit 115 under the absorption section 115c, so that the flow of the distillation liquid 43 flows through the thermosiphon. In the embodiments shown in FIG. 6 and 12, a heat exchanger 10 is used outside the processing unit 115, and the cooling section of the feed gas 115a is located in the processing unit 115 under the absorption section 115c, so that the flow of distillation liquid 43 flows through the thermosiphon. (In the embodiments shown in FIGS. 5, 6, 11 and 12, the reflux pump 19 is used to supply reflux to locations above that point in the processing unit 115 where the liquid phase condensed from stream 38 is collected.) In some cases, distillation liquid stream 43 can be used to cool stream 32 in a heat exchanger mounted outside the processing unit 115, such as the heat exchanger 10 shown in FIG. 3-9. In some cases, it is possible to dispense with heating the flow of distillation liquid 43 in general, and use the flow of distillation liquid 43 as reflux by feeding it to the upper region of the deethanizer section 1156, as shown in FIG. 7 and 13 (for the embodiment shown in FIG. 13, a pump 22 may be required; gravity flow 43 may not be possible.).

Depending on the content of heavier hydrocarbons in the feed gas and on the pressure of the feed gas, the cooled first and second portions 32 and 33 entering the separator section 115e in FIG. 2 or to the separator 11 in FIG. 8 (or a cooled feed gas stream 31a entering

- 8 025641 separator section 115e in FIG. 3-7 or to the separator 11 in FIG. 9-13), may not contain liquids (because their temperatures are above the dew point or their pressure is greater than Cricondenbar) In such cases, there is no fluid flow 35 (shown by a dashed line). And then the separator section 115e in the processing plant 115 (Fig. 2-7) or the separator 11 (Fig. 8-13) may be unnecessary.

In accordance with the present invention, external cooling may be used in addition to cooling the feed gas and / or the first distillation vapor stream with a second distillation vapor stream and a distillation liquid stream, especially in the case of rich feed gas. In cases where additional cooling of the feed gas is necessary, a heat and mass transfer device (or a collector for collecting gas in cases where the cooled first and second parts 32 and 33 or the cooled feed stream 31a does not contain liquid) can be included in the separator section 115e, as shown the dashed line in FIG. 3-7, or the heat and mass transfer device may be included in the separator 11, as shown by the dashed line in FIG. 9-13. This heat and mass transfer device may be a finned tube heat exchanger, a plate heat exchanger, a heat exchanger with aluminum brazed plates, or another type of heat exchanger, including multi-pass and / or multi-service heat exchangers. This heat and mass transfer device is configured to provide heat exchange between the flow of the refrigerant (e.g., propane) flowing through the passage of the heat and mass transfer device, the flow of the vapor portion 31a floating up, so that the refrigerant cools the steam even more and condenses more liquid that flows down, combining with fluid flow 35. As shown by the dotted line in FIG. 2 and 8, the heat and mass transfer device in the separator section 115e (Fig. 2) or the separator 11 (Fig. 8) may include devices that provide additional refrigerant cooling. Alternatively, a conventional gas freezer may be used to cool stream 32, stream 33, and / or stream 31a with refrigerant before streams 32 and 33 enter separator section 115e (FIG. 2) or separator 11 (FIG. 8), or before as stream 31a enters separator section 115e (FIGS. 3-7) or separator 11 (FIGS. 9-13). In cases where additional cooling of the first distillation steam stream is necessary, the heat exchanger in the condensation section 115b of the processing unit 115 (Figs. 2-5, 7-11 and 13) or the heat exchanger 10 (Figs. 6 and 12) may have devices that provide additional refrigerant cooling as indicated by the dotted line.

Depending on the type of heat exchanger selected for the heat exchanger in the cooling section of the feed gas 115a and the condensation section 115b, these heat exchangers can be combined into one multi-pass and / or multi-service heat exchanger. In such cases, this multi-pass and / or multi-service heat exchanger will include appropriate means for distributing, separating and combining stream 31, stream 32, stream 33, the first distillation vapor stream 38, any vapor released from the cooled stream 38 and the second distillation vapor stream, to produce the required cooling and heating.

It should be recognized that the relative amount of condensed liquid that is distributed between streams 41 and 42 in FIG. 2-6 and 8-12 will depend on many factors, including gas pressure, gas composition and available power. In some cases, it may be better to load all the condensed liquid in the upper region of the absorption section 115c into the stream 41 rather than in the upper region of the deethanizer section 1154 into the stream 42 shown by the dashed line. In such cases, the heated stream of distillation liquid 43a can be fed into the upper region of the deethanizer section 1154 as a reflux.

The present invention provides a more complete extraction of C3 components and heavier hydrocarbons in terms of the costs associated with the implementation of the method. The reduction in the cost of implementing the method can be manifested in the form of a decrease in the energy consumption for compression or re-compression, a decrease in the energy consumption for external cooling, a decrease in the energy consumption for reboiling the column, or a combination thereof.

Although the preferred embodiments of the invention have been described herein, it will not be difficult for those skilled in the art to make changes to them, for example, adapting the invention to various conditions, types of feedstock or other requirements without departing from the spirit of the present invention set forth in the following formula.

Claims (32)

CLAIM (1) a first heat exchanger located inside the processing unit 115 in the feed gas cooling section 115a and intended to cool the gas stream 31; (1) said gas stream 31 is cooled in a first heat exchanger located inside a processing unit 115 comprising a feed gas cooling section 115a, a condensation section 115b, an absorption section 115c, and a deethanizer section 1154; 1. A method for separating a gas stream 31 containing methane, C ₂ components, C ₃ components and heavier hydrocarbons, into the volatile fraction 44 of the residual gas and a relatively less volatile fraction 37 containing the bulk of these C ₃ components and heavier hydrocarbons, where: (2) an expansion device 13 connected to the first heat exchanger to receive the cooled gas stream 31a, 34 and to obtain a stream 34a expanded to a lower pressure; 2. The method according to claim 1, where: (a) the gas stream 31 in step (1) is cooled in said first heat exchange device sufficiently to partially condense it; (b) a partially condensed gas stream 31a is supplied to a separation device in a separator section 115e located inside the processing unit 115, and it is divided into a vapor stream 34 and at least one liquid stream 35; (c) the steam stream 34 is expanded 13 to a lower pressure, followed by additional cooling 34a; (2) the cooled gas stream 31a, 34 is expanded 13 to a lower pressure to form an additionally cooled stream 34a; (3) an absorption device located inside said processing unit 115 of the absorption section 115c and connected to the expansion device 13 for receiving the expanded gas stream 34a after cooling as a bottom stream; 3. The method according to claim 1, where: (a) the first distillation liquid stream 43 in step (4) is withdrawn from the bottoms of said absorption device and heated in a third heat exchanger 10, and then the first distillation liquid stream 43a subjected to heating is then fed as an overhead to said mass transfer device; (b) the first distillation steam stream 38 in step (5) is withdrawn from the upper region of said mass transfer device and sufficiently cooled so that at least a portion of the vapor is condensed in the third heat exchange device 10 by at least partially heating in the step (a) while forming a condensed stream 41 and a residual vapor stream. (4) a first liquid collecting device located inside processing unit 115 and connected to an absorption device for receiving a first distillation liquid stream 43 from the bottom section of the absorption device; 4. The method according to claim 3, where: (ί) the gas stream 31 in step (1) is cooled in said first heat exchanger sufficiently to partially condense it; (i) a partially condensed gas stream 31a is supplied to said separation device (4) a first distillation liquid stream 43 is withdrawn from the bottoms of said absorption device and fed as overhead 43a to a mass transfer device located within said deethanizer section 1156 of processing unit 115; (5) a mass transfer device located inside the processing unit 115 in the deethanizer section 115ά and connected to the first liquid collecting device, for receiving the first distillation liquid stream 43 in the form of an overhead; 5. The method according to claim 1, where: (a) the gas stream 31 in stage (1) is subjected to partial cooling in the specified first heat exchange device; (b) the partially cooled gas stream is divided into the first part 32 and the second part 33; (c) said first part 32 is subjected to further cooling in an additional heat and mass transfer device located inside said separation device, thereby simultaneously condensing any less volatile components 35 from said first part; (ά) said second part 33 is subjected to further cooling in said first heat exchange device; (e) the first part 32 subjected to additional cooling and the second part subjected to additional cooling 33 are mixed to form a stream of chilled gas 34; (ί) the first distillation liquid stream 43 in step (4) is collected from the bottom of the indicated absorption device and heated in an additional heat and mass transfer device by at least partial cooling in stage (c), and then the first distillation liquid stream 43a subjected to heating is supplied as the overhead in the specified mass transfer device; (e) said combined steam stream is heated in said first heat exchanger due to at least partial cooling in steps (a) and (ά), and then the combined steam stream subjected to heating is withdrawn as a volatile fraction 44 of the residual gas from said processing unit 115. (5) the first distillation steam stream 38 is taken from the upper region of said mass transfer device and cooled sufficiently so that at least a portion of the steam is condensed in a second heat exchange device located inside the condensation section 115b of the processing unit 115, thereby forming a condensed stream and a residual vapor stream containing any non-condensing vapor remaining after cooling the first distillation vapor stream; (6) the absorption device is connected to an expansion device 13 for receiving the gas stream 34a which has undergone expansion after cooling in the form of a bottoms; (e) an additional expansion device 12 is connected to the specified separation device for receiving and expanding at least one fluid stream 35 to a lower pressure 35a; (ί) the first heat exchange device is additionally connected to an additional expansion device 12 for receiving and heating at least one fluid stream 35a subjected to expansion due to at least partial cooling in step (a) and is additionally connected to a mass transfer device for supplying at least at least one subjected to heating after expansion of the flow of fluid 35b in the form of a still bottom. (6) a first steam collection device located inside the processing unit 115 and connected to the mass transfer device for receiving from the upper region of the mass transfer device a first distillation steam stream 38; 6. The method according to claim 5, where: (a) the second part 33 subjected to additional cooling in step (ά) is sent to said separation device in order to mix any liquids condensed during the additional cooling of the first part and the additional cooling of the second part, forming at least one liquid stream 35, with the remainder additional cooling of the first part and subjected to additional cooling of the second part form a stream 34 of steam; (b) said steam stream 34 is expanded 13 to a lower pressure to form an additionally cooled stream 34a; (c) the expanded chilled steam stream 34a is fed as bottoms to said absorption device; (ά) at least one fluid stream 35 is expanded 12 to a lower pressure 35a; (e) at least one expandable liquid stream 35a is heated in said first heat exchanger by at least partially cooling the gas stream 31, and then at least one expanding and heating liquid stream 35b is fed as bottoms to said mass transfer device. (6) the expanded chilled steam stream 34a is fed as bottoms to said absorption device; (e) at least one fluid stream 35 is expanded 12 to a lower pressure 35a; (ί) the expanded at least one fluid stream 35a is heated in said first heat exchanger by at least partial cooling in step (a), and then the at least one fluid stream 35b subjected to heating and expansion is fed as bottoms to the specified mass transfer device. (6) at least a portion of the condensed stream 41 is supplied as an overhead stream to said absorption device; (7) a second heat exchange device located inside the processing unit 115 in the condensation section 115b and connected to the first steam collection device to receive the first 7. The method according to claim 5, where: (ί) said first part 32 in step (c) is further cooled in a third heat exchange device 10; (ίί) the first distillation liquid stream 43 in step (4) is withdrawn from the bottoms of said absorption device and heated in the third heat exchanger 10 due to at least partial cooling in stage (ί) and then the first distillation stream 43a subjected to heating served as the overhead in the specified mass transfer device. (7) a second distillation steam stream is collected from the upper region of said absorption device and is heated in said second heat exchange device by at least partial cooling in step (5); (8) said absorption device is further connected to said second heat exchange device for receiving at least a portion of said condensed stream 41 as an overhead; 8. The method according to claim 7, where: (a) the first part 32a subjected to additional cooling in step (ί) and the second additional cooling part 33 are mixed to form a partially condensed gas stream 31a; (b) a partially condensed gas stream 31a is supplied to said separation device and subjected to separation into a vapor stream 34 and at least one liquid stream 35; (c) said steam stream 34 expands 13 to a lower pressure and forms an additionally cooled stream 34a; (ά) the expanded chilled steam stream 34a is fed as bottoms to (8) the second distillation steam stream subjected to heating is mixed with the residual steam stream to form a combined steam stream; (9) a second steam collection device located inside the processing unit 115 and connected to the absorption device for receiving a second stream of distillation steam from the upper region of the absorption device; 9. The method according to claims 4-6 or 8, where the separation device 11 is located outside the specified processing unit 115. (9) the combined steam stream is heated in said first heat exchanger located inside said charge gas cooling section 115a by at least partially cooling in step (1) and then the combined steam stream subjected to heating is withdrawn as a residual vapor fraction 44 gas from said processing unit 115; - 9 025641 (3) the gas stream 34a which has undergone expansion after cooling is supplied as bottoms to an absorption device located inside said absorption section 115c of the processing unit 115; (10) a second heat exchange device is further connected to a second steam collection device for receiving a second stream of distillation steam and heating it by at least partially cooling in step (5) of the method according to claim 1; 10. The method according to claims 3-8 or 9, where: (a) the first heated distillation liquid stream 43a subjected to heating in step (ί) is supplied to said mass transfer device in the intermediate loading section; (b) separating said condensed stream in step (5) at least into a first reflux stream 41 and a second reflux stream 42; (c) said first reflux stream 41 is supplied to said absorption device as an overhead; (ά) said second reflux stream 42 is supplied to said mass transfer device in the form of an overhead stream. - 10 025641 and divide it into a vapor stream 34 and at least one liquid stream 35; (iii) the steam stream 34 is expanded 13 to a lower pressure, followed by additional cooling 34a; (ίν) the expanded, cooled vapor stream 34a is supplied as bottoms to said absorption device; (ν) at least one fluid stream 35 is expanded 12 to a lower pressure 35a; (νί) the expanded at least one fluid stream 35a is heated in said first heat exchanger by at least partial cooling in step (ί), and then the heated and expanded at least one fluid stream 35b is fed as bottoms to the specified mass transfer device. (10) a second distillation liquid stream is collected from the bottom region of said mass transfer device and heated in a heat and mass transfer device located below the mass transfer device inside said deethanizer section 1156 of processing unit 115, while stripping off more volatile components from the second distillation liquid stream, and then subjected to heating and steaming a second stream of distillation liquid from the processing unit as a specified relatively less volatile fraction 37; (11) a combining device connected to said second heat exchanger to receive a heated second stream of distillation steam and any said residual steam stream to form a combined steam stream; 11. The method according to claims 1, 3 or 7, where: (a) a gas collection manifold is disposed within the processing unit 115 in the separator section 115e; (b) an additional heat and mass transfer device is included in the composition of the specified collector for collecting gas, and the additional heat and mass transfer device contains one or more channels for external refrigerant; (c) the gas stream 31a subjected to cooling in step (1) is supplied to a gas collection manifold and sent to said additional heat and mass transfer device for additional cooling with an external refrigerant; (ά) said additionally cooled gas stream 34 is expanded 13 to a lower pressure, and then the expanded cooled stream 34a is supplied as bottoms to said absorption device. - 11 025641 specified absorption device; (e) at least one fluid stream 35 is expanded 12 to a lower pressure 35a; (ί) at least one expanding liquid stream 35a is heated in said first heat exchanger by at least partially cooling said gas stream 31 and at least one expanding and heating stream 35b is supplied as bottoms in the specified mass transfer device. (11) regulate the amount and temperature of the specified feed streams 34a, 41 entering the specified absorption device, so as to maintain in the upper region of the absorption device a temperature at which the bulk of the components are recovered to the specified relatively less volatile fraction 37. (12) the first heat exchange device is additionally connected to a combining device for receiving the combined steam stream and heating it by at least partially cooling in step (1) of the method according to claim 1, and means for outputting the combined steam stream subjected to heating in the form of a volatile residual gas fractions 44 from the top of said processing unit 115; - 12 025641 of the distillation steam stream 38 and its sufficient cooling so that at least a portion of the vapor is condensed, thereby forming a condensed stream 41 and a residual vapor stream containing any non-condensing vapor remaining after cooling of the first distillation vapor stream 38; 12. The method according to PP.2, 5, 6, 8, 9 or 10, where: (a) an additional heat and mass transfer device is arranged inside said separation device, wherein the additional heat and mass transfer device comprises one or more channels for external refrigerant; (b) said steam stream 34 in step (b) is sent to an additional heat and mass transfer device for cooling with an external refrigerant to form additional condensate; (c) said condensate is mixed with at least one fluid stream 35 in step (b), separated by separation. - 13 025641 (ί) the first heat exchanger device is designed to cool the gas stream 31 sufficiently for its partial condensation 31a; (ίί) said separation device is connected to a first heat exchange device for receiving a partially condensed gas stream 31a and separating it into a vapor stream 34 and at least one liquid stream 35; (ίίί) an expansion device 13 is connected to a separation device for receiving and expanding the steam stream 34 to a lower pressure, subjecting it to additional cooling 34a; (ίν) the absorption device is connected to the expansion device 13 for receiving the expanded steam stream 34a subjected to expansion in the form of a bottoms; (ν) an additional expansion device 12 is connected to the specified separation device for receiving and expanding at least one fluid stream 35 to a lower pressure 35a; (νί) said first heat exchanger is further connected to said second expansion device 12 for receiving and heating at least one expanded fluid stream 35a due to at least partial cooling in step (ί) of the method according to claim 4 and further connected with the specified mass transfer device for supplying at least one subjected to heating after expansion of the fluid stream 35b in the form of a still bottom. (13) a second liquid collecting device located inside the processing unit 115 and connected to said mass transfer device to receive a second stream of distillation liquid from the bottom area of the mass transfer device; 13. The method according to claim 3, where the specified third heat exchange device 10 is placed inside the processing unit 115. - 14 025641 receiving said first part 32 and its additional cooling 32a; (ίί) an additional combining device connected to the third heat exchanger 10 and to the first heat exchanger for receiving subjected to additional cooling of the first part 32A and subjected to additional cooling of the second part 33 and the formation of a cooled gas stream 31a; (ίίί) a third heat exchange device 10 is additionally connected to said first liquid collecting device for receiving the first distillation liquid stream 43 and heating it by at least partial cooling in step (ί) of the method according to claim 7; (ίν) a mass transfer device is connected to a third heat exchange device 10 for receiving the first heated distillation liquid stream 43a subjected to heating as an overhead. (14) a heat and mass transfer device located inside the processing unit 115 below the specified mass transfer device in the deethanizer section 1156 and connected to a second liquid collection device for receiving and heating a second stream of distillation liquid and thus simultaneously evaporating from more volatile components from said second a distillation liquid stream and a means for withdrawing a second distillation liquid stream subjected to heating and steam from the processing unit in the form of relatively less volatile fraction 37; 14. The device for implementing the method according to claim 1 for separating a gas stream 31 containing methane, C ₂ components, C ₃ components and heavier hydrocarbons, into a volatile fraction 44 of the residual gas and a relatively less volatile fraction 37 containing the specified main part C ₃ components and heavier hydrocarbons containing: - 15 025641 (s) an absorption device is designed to connect to the specified additional separation device for receiving the specified first reflux stream 41 in the form of an overhead; (b) the specified mass transfer device is designed to connect with the specified additional separation device for receiving the specified second reflux stream 42 in the form of an overhead. 15. The device according to 14, in which: (a) the first heat exchanger is designed to cool the gas stream 31 sufficiently to undergo partial condensation 31a; (b) a separation device is disposed within the processing unit 115 in the separation section 115e and connected to a first heat exchange device for receiving a partially condensed gas stream 31a and separating it into a vapor stream 34 and at least one liquid stream 35; (c) an expansion device 13 is connected to said separation device for receiving and expanding the vapor stream 34 to a lower pressure, subjecting it to additional cooling 34a; (15) a control device for controlling the amount and temperature of said feed streams 34a, 41 entering the absorption device, so as to maintain in the upper region of the absorption device a temperature at which a majority of the components are recovered in the relatively less volatile fraction 37. 16. The device according to 14, in which: (a) a third heat exchange device 10 is connected to a first liquid collecting device for receiving and heating a first distillation liquid stream 43; (b) a mass transfer device is connected to a third heat exchange device for receiving the heated first distillation liquid stream 43 a as an overhead; (c) said third heat exchanger is further connected to a first steam collection device for receiving said first distillation steam stream 38 and cooling it sufficiently so that at least a portion of the steam is condensed by at least partial cooling in step (b) the method according to claim 3, while forming a condensed stream 41 and a stream of residual steam. 17. The device according to clause 16, in which: 18. The device according to 14, in which: (a) the first heat exchanger is intended to partially cool the gas stream 31; (b) a separation device is connected to a first heat exchanger for receiving a partially cooled gas stream 31 and separating it into a first part 32 and a second part 33; (c) an additional heat and mass transfer device located inside the separation device (11) is connected to a separation device for receiving and additional cooling said first part 32 and simultaneously condensing less volatile components 35 therefrom; (i) said first heat exchanger is further connected to said separation device for receiving said second part 33 and further cooling it; (e) an additional combining device is connected to an additional heat and mass transfer device and a first heat exchange device for receiving the first part 32 subjected to additional cooling and subjected to additional cooling of the second part 33 and the formation of a cooled gas stream 34; (ί) an expansion device 13 is connected to a second combining device for receiving said cooled stream 34 and forming a stream 34a expanded to a lower pressure; (e) an additional heat and mass transfer device is additionally connected to the first device for collecting liquid for receiving and heating the first stream 43 of distillation liquid due to at least partial cooling in step (c) of the method according to claim 5; (B) a mass transfer device is connected to an additional heat and mass transfer device for receiving the first distillation liquid stream 43a subjected to heating in the form of an overhead; (ί) said first heat exchanger is further connected to said combining device for receiving the combined steam stream and heating it by at least partially cooling in stages (a) and (i) of the method according to claim 5 and means for outputting the heated the combined steam stream as the volatile fraction 44 of the residual gas from the processing unit 115. 19. The device according to p, in which: (a) said separation device 11 is further connected to said first heat exchanger for receiving a second cooling portion 33 subjected to further cooling, in which any liquids condensing upon further cooling of the first portion 32 and additional cooling of the second portion 33 are mixed to form at least one stream 35 liquids, the vapors remaining after additional cooling of the first part 32 and additional cooling of the second part 33 form a vapor stream 34; (b) an expansion device 13 is connected to a separation device 11 for receiving and expanding the vapor stream 34 to form expanded to a lower pressure due to the additionally cooled stream 34a; (c) the absorption device is connected to an expansion device 13 for receiving the expanded cooled vapor stream 34a in the form of a bottoms; (i) an additional expansion device 12 is connected to the specified separation device 11 for receiving and expanding at least one fluid stream 35 to a lower pressure 35a; (e) a first heat exchange device is further connected to said second expansion device 12 for receiving said at least one fluid stream 35a subjected to expansion and its heating due to at least partial cooling of said gas stream 31 and is further connected to said mass transfer device for the supply of at least one subjected to heating after expansion of the flow of fluid 35b in the form of a still bottom. 20. The device according to p, in which: (ί) the third heat exchange device 10 is connected to the specified separation device for 21. The device according to claim 20, in which: (a) an additional combining device is designed to receive subjected to additional cooling of the first part 32A and subjected to additional cooling of the second part 33 and the formation of the partially condensed gas stream 31a; (b) said separation device is connected to an additional combining device for receiving a partially condensed gas stream 31a and separating it into a vapor stream 34 and at least one liquid stream 35; (c) an expansion device 13 is connected to said separation device for receiving and expanding the vapor stream 34 to a lower pressure, forming an additionally cooled stream 34a; (i) an absorption device is connected to an expansion device 13 for receiving the expanded steam stream 34a expanded as a bottom stream; (e) an additional expansion device 12 is connected to said separation device for receiving said at least one fluid stream 35 and expanding it to a lower pressure 35a; (ί) the first heat exchange device is additionally connected to the specified additional expansion device 12 for receiving at least one subjected to expansion of the flow of fluid 35A of the liquid and its heating due to at least partial cooling of the specified gas flow and is additionally connected to the specified mass transfer device for supplying at least one subjected to heating after expansion of the flow of fluid 35b in the form of a still bottom. 22. The device according to p, in which the additional heat transfer device is located in the specified processing unit 115. 23. The device according to clause 15 or 17, in which the separation device is located outside the processing plant 115. 24. The device according to clause 16 or 20, in which: (a) the mass transfer device is intended to be connected to a third heat exchange device 10 for receiving the first heated distillation liquid stream 43 a subjected to heating in the intermediate loading section; (b) a separation device is connected to said additional heat exchange device for receiving the condensed stream 40, 40a and separating it into at least a first reflux stream 41 and a second reflux stream 42; (c) an absorption device is connected to said separation device for receiving said first reflux stream 41 as an overhead; (i) said mass transfer device is connected to said separation device for receiving said second reflux stream 42 as an overhead. 25. The device according to PP.15, 22, in which: (a) the mass transfer device is intended to be connected to an additional heat exchange device for receiving the first distillation liquid stream 43 a subjected to heating in the intermediate loading section; (b) an additional separation device is connected to a second heat exchanger for receiving said condensed stream and separating it into at least a first reflux stream 41 and a second reflux stream 42; (c) said absorption device is connected to said additional separation device for receiving said first reflux stream 41 as an overhead; (i) said mass transfer device is connected to said additional separation device for receiving said second reflux stream 42 as an overhead. 26. The device according to p or 19, in which: (a) the mass transfer device is connected to an additional heat and mass transfer device for receiving the first heated distillation liquid stream 43a from element (d) in the intermediate loading section; (b) an additional separation device is connected to said second heat exchange device for receiving a condensed stream and separating it into at least a first reflux stream 41 and a second reflux stream 42; 27. The device according to 14 or 16, in which: (a) a gas collection manifold is disposed within the processing unit 115 in the separator section 115e; (b) an additional heat and mass transfer device is placed inside the specified collector for collecting gas, and the specified additional heat and mass transfer device contains one or more channels for external refrigerant; (c) said collector for collecting gas is connected to a first heat exchanger for receiving the cooled gas stream 31a and directing it to said additional heat and mass transfer device for additional cooling by external refrigerant; (b) an expansion device 13 is designed to connect to the specified collector for collecting gas to receive the specified subjected to additional cooling gas stream 34 and expand to a lower pressure to form a stream 34a and is additionally connected to an absorption device for supplying the specified subjected to expansion after additional cooling of the stream 34a gas in the form of bottoms. 28. The device according to claim 20, in which: (a) a gas collection manifold is disposed within the processing unit 115 in the separator section 115e; (b) an additional heat and mass transfer device is placed inside the specified collector for collecting gas, and the specified additional heat and mass transfer device contains one or more channels for external refrigerant; (c) said collector for collecting gas is connected to a second combining device for receiving the gas stream subjected to cooling and directing it to said additional heat and mass transfer device for additional cooling with an external refrigerant; (b) the expansion device 13 is designed to connect to the specified collector for collecting gas to receive the specified subjected to additional cooling gas stream 34 and expand to a lower pressure 34a and is additionally connected to an absorption device for supplying the specified subjected to expansion after additional cooling of the gas stream 34a in the form of bottoms. 29. The device according to PP.15, 17, 21-23 or 24, in which: (a) an additional heat and mass transfer device is placed inside the separation device, wherein said additional heat and mass transfer device contains one or more channels for external refrigerant; (b) said steam stream is directed to said additional heat and mass transfer device and is thus subjected to external cooling with the formation of additional condensate; and (c) said condensate is mixed with at least one fluid stream 35 separated by separation. 30. The device according to p. 18 or 19, in which the specified separation device is placed inside the processing unit 115. 31. The device according to item 21, in which the specified device 11, 115e separation is placed inside the processing unit 115. 32. The device according to clause 15, where the specified third heat exchange device 10 is placed inside the processing unit 115.