EA023977B1 - Hydrocarbon gas processing - Google Patents

Abstract

A process and an apparatus are disclosed for a compact processing assembly to recover Ccomponents (or Ccomponents) and heavier hydrocarbon components from a hydrocarbon gas stream. The gas stream is cooled and divided into first and second streams. The first stream is further cooled to condense substantially all of it, expanded to lower pressure, and supplied as top feed to an absorbing means. The second stream is also expanded to lower pressure and fed to the bottom of the absorbing means. A distillation vapor stream from the absorbing means is heated by cooling the gas stream and the first stream. A distillation liquid stream from the absorbing means is fed to a heat and mass transfer means to heat it and strip out its volatile components while cooling the gas stream. The absorbing means and the heat and mass transfer means are housed in the processing assembly.

Description

SUMMARY OF THE INVENTION

Hydrocarbons such as ethylene, ethane, propylene, propane, as well as heavier ones, can be extracted from various gases, for example, from natural, refinery and synthesized gas obtained from the processing of other hydrocarbon materials, such as coal, crude oil, gasoline-naphtha fraction, combustible shales, oil sands and brown coal. Natural gas consists mainly of methane and ethane, i.e. the molar percentage of methane and ethane in the gas reaches 50%. The gas also contains relatively small amounts of heavier hydrocarbons such as propane, butane, pentane and the like, as well as hydrogen, nitrogen, carbon monoxide and other gases.

The present invention mainly addresses the process of recovering ethylene, ethane, propylene, propane and heavier hydrocarbons from such gas streams. A gas suitable for processing in accordance with the present invention has the following typical composition, expressed in approximate molar content: 90.0% methane; 4.0% ethane and other C ₂ components; 1.7% propane and other C ₃ components; 0.3% isobutane; 0.5% standard butane; as well as 0.8% of pentanes and heavier hydrocarbons, the balance is maintained by nitrogen and carbon dioxide. The presence of sulfur-containing gases is also sometimes noted.

Historically formed cyclical changes in prices for both natural gas and its gas condensate (N00 components at times determine a decrease in the growth of ethane, ethylene, propane, propylene and heavier components as liquid products. As a result, a need has arisen for technological processes that could provide more efficient extraction of these products from raw gas, while the extraction efficiency should be accompanied by a reduction in investment. aterialov include processes which are based on cooling and liquefaction of gas, oil absorption, and refrigerated oil absorption. Additionally, cryogenic processes gained popularity, due to the presence of economical equipment generating electric power by the gas in an expander direction while discharging heat from the process gas.

Depending on the pressure of the gas supply source, the saturation of the gas (ethane, ethylene and heavier hydrocarbon components), as well as on the desired final product, any of these processes or their combination can be applied.

Today, for the processing of natural gas condensate, the cryogenic expansion process is mainly preferred, since it combines maximum simplicity, ease of commissioning, operational flexibility, high efficiency, safety and high reliability. U.S. Patents 3,292,380; 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; in the replacement US patent No. 33408; as well as in simultaneously pending applications under numbers 11/430412; 11/839693; 11/971491; 12/206230; 12/689616; 12/717394; 12/750862; 12/772472; 12/781259; 12/868993; 12/869007; 12/869139; 12/979563 describes the corresponding processes (although in the description of the present invention, in some cases, processing modes other than those described in these US patents are used).

In a typical cryogenic expansion process, the pressurized gas is cooled by heat exchange with other process streams and / or with external cooling sources, such as propane compression cooling system. As the gas cools, condensation and condensate collection occurs in one or more separators, since the condensate under high pressure contains a certain amount of necessary C ₂ + components. Depending on the saturation of the gas and the amount of condensate obtained, the condensate under high pressure can be expanded at lower pressure and fractionated. The evaporation that occurs during expansion of the condensate results in further cooling of the working stream. Under certain conditions, it may be necessary to pre-cool the condensate under high pressure before expanding it to further reduce the temperature as a result of the expansion. The expanded working stream, consisting of a mixture of condensate and vapor, is separated into fractions in a distillation column (demetanizer or deethanizer). Inside the column, the cooled stream is subjected to rectification in order to separate residual methane, nitrogen and other volatile gases in the form of helium vapors from the required C ₂ components, C ₃ components and heavier hydrocarbon components, which are discharged from the bottom of the column as a liquid bottoms product; or for the purpose of separating residual methane, C2 components, nitrogen and other volatile gases in the form of helium vapors from the desired C3 components and heavier hydrocarbon components that are discharged from the bottom of the column as a liquid bottoms product.

In the case of incomplete condensation of the feed gas (this usually happens), the vapors remaining after incomplete condensation can be divided into two streams. One part of the vapor is directed through an expander or expansion valve into a vessel with a lower pressure, where additional condensation of the liquid occurs as a result of further cooling of the working stream. The pressure after expansion is actually equal to the pressure under which the distillation column operates. The vapor and liquid phases obtained as a result of expansion are fed into the column as raw materials.

- 1,023977

The remaining vapors are cooled to complete condensation by heat exchange with other process streams, for example, with the upper cold product of the rectification column. Before cooling, these vapors can be mixed with part of the condensate under high pressure or with its entire volume. The resulting cooled stream is then expanded in a suitable device, for example in an expansion valve, of the working pressure of the demethanizer. During the expansion process, part of the condensate evaporates, as a result of which the main working stream is cooled. The evaporation-throttled stream is then fed to the top of the demethanizer. Typically, the vapor component of the throttled vaporization stream and the helium vapor from the demethanizer are mixed in the upper separator section of the distillation column and form residual synthetic methane gas. Alternatively, it is possible to supply a cooled expanded working stream to the separator, for its separation into vapor and liquid streams. The vapor stream is mixed with the helmet pairs of the column, and condensate is supplied to the top of the column as liquid feed.

The present invention employs the latest means of implementing the various steps of the above process, which improves overall efficiency and reduces the number of required pieces of equipment. This is achieved by combining in a single installation several units of equipment that were previously independent, while reducing the area needed to accommodate the technological installation, as well as reducing capital costs. Unexpectedly, the applicants found that a more compact scheme also contributes to a significant reduction in power consumption necessary to achieve a given level of processing, which generally increases technological efficiency and reduces the cost of operation of the installation. In addition, a more compact layout scheme eliminates a significant part of the pipelines that connected individual pieces of equipment in installations of a traditional design, which further reduces capital costs and allows you to remove the corresponding flange connections for connecting pipelines from the structure. Since hydrocarbon leakages (which are volatile organic compounds (VOCs) involved in the formation of gases causing the greenhouse effect, as well as creating the prerequisites for the formation of holes in the ozone layer) are possible on flanged pipe joints, the rejection of these flanges in the design reduces the possibility pollutant emissions into the atmosphere.

In accordance with the present invention, it was found that it is possible to achieve a C ₂ emission level _of more than 88%. Similarly, in cases where the allocation of C ₂ components is undesirable, it is possible to isolate C ₃ components at a level exceeding 93%. In addition, the present invention allows for 100% separation of methane (or C ₂ components) and components lighter than C ₂ components (or C ₃ components), as well as heavier components, at a lower energy intensity compared with the prior art , while the level of excretion remains unchanged. The present invention (despite the fact that it is implemented at lower pressures and higher temperatures) is particularly effective in the processing of feed gases, in the pressure range from 400 to 1500 psi abs. [from 2758 to 10342 kPa (a)] or higher, under conditions where the temperature of the upper product of the gas condensate recovery column is within -50 ° P [-46 ° C] or lower.

To facilitate understanding of the essence of the present invention, the following drawings and examples are provided in the description.

References to the drawings:

FIG. 1 is a block diagram of a natural gas processing plant made in accordance with the prior art according to US Pat. No. 4,157,904;

FIG. 2 is a block diagram of a natural gas processing plant in accordance with the present invention;

FIG. 3-17 are flowcharts illustrating alternative methods of using the present invention to process a natural gas stream.

In the following description of the above figures, tables with summary data on gas consumption calculated for typical processing modes are provided. In the tables given in this document, the gas flow rate (mol / h) is rounded to the nearest whole number for readability. The total flow rates shown in the tables take into account all non-hydrocarbon components, and therefore, are greater than the values of the total flow rate of hydrocarbon components. The temperature values shown in the tables are approximate, rounded to the degree. It should also be noted that the calculations of technological schemes in order to compare the efficiency of the technological processes shown in the figures are based on the assumption that there is no heat leakage between the environment and the process (in both directions). The quality of insulating materials on the market allows us to consider this assumption to be reasonable, although specialists with the appropriate level of technical training usually use it in their calculations.

For ease of perception, technological parameters are indicated both in traditional British units of measurement and in units of measurement of the International System of Units (SI). The molar gas flow rates indicated in the tables can be expressed either as pound mol / h or as kilogram mol / h. The energy consumed, expressed in horsepower (hp) and / or in thousands of British thermal units, 2,023,977 yards per hour (MBTU / h), corresponds to the indicated molar flow rate, expressed in pound moles per hour. The energy consumed, expressed in kilowatts (kW), corresponds to the indicated molar flux expressed in kilogram moles per hour.

Description of the prior art

In FIG. 1 is a flowchart of a technological process that shows the design of a processing plant designed to separate C ₂ + components from natural gas, implemented on the basis of well-known technical solutions, in accordance with US patent No. 4157904. According to this process simulation scheme, the incoming gas enters the installation at a temperature of 101 ° P [39 ° C] and a pressure of 915 psi abs. [6.307 kPa (a)] as stream 31. If the incoming gas contains sulfur compounds in a concentration that violates the requirements for the composition of the working stream, they are removed from the incoming gas using an appropriate pre-treatment unit (not shown in the diagram). In addition, the feed stream is usually subjected to dehydration in order to prevent the formation of hydrate (ice) in cryogenic treatment modes. A solid adsorbent is usually used for these purposes.

The feed stream 31 is divided into two - streams 32 and 33. Stream 32 is cooled to -31 ° P [-35 ° C] in the heat exchanger 10 by heat extraction with cold residual gas (stream 41a), and stream 33 is cooled to -37 ° P [-38 ° C] in the heat exchanger 11 due to heat removal by the liquid condensate of the demethanizer reboiler having a temperature of 43 ° P [6 ° C] (stream 43), and by-product liquid condensate of the reboiler having a temperature of -47 ° P [-44 ° C ] (stream 42). Streams 32a and 33a recombine and form a stream 31a, which enters the separator 12 at a temperature of -33 ° P [-36 ° C] and a pressure of 893 psi abs. [6.155 kPa (a)], where the vapor (stream 34) is separated from the liquid condensate (stream 35).

The steam (stream 34) from the separator 12 is divided into two streams: stream 36 and stream 39.

Stream 36, containing about 32% of the total vapor volume, is mixed with the concentrate in the separator (stream 35), and the resulting stream 38 is passed through a heat exchanger 13, where heat is removed through interaction with cold residual gas (stream 41); here, the working stream is cooled to its full condensation.

The resulting condensed stream 38a at a temperature of -131 ° P [-90 ° C] is then subjected to rapid evaporation through expansion valve 14 to a working pressure (approximately 410 psi abs. [2827 kPa (a)]) of distillation column 18. B During the expansion process, part of the stream evaporates, as a result of which the main work stream is cooled. In the process illustrated in FIG. 1, the expanded stream 38b after the expansion valve 14 reaches a temperature of -137 ° P [-94 ° C], and then is fed to the separation section 18a in the upper zone of the distillation column 18. The liquid condensate separated in the separator becomes raw material for the upper feed to the section demethanization 18b.

The remaining 68% of the volume of steam from the separator 12 (stream 39) is supplied to the working expander 15, where the energy of this part of the raw material, which is under high pressure, is converted into mechanical energy. In the expander 15, the vapor undergoes isentropic expansion to the operating pressure of the column, while the expanded stream 39a is cooled to a temperature of about -97 ° P [-72 ° C]. Typical expanders on the market make it possible to isolate about 80-85% of technological raw materials, theoretically available with perfect isentropic expansion. The energy released is often used to drive a centrifugal compressor (such as element 16), which, for example, can be used to re-compress the residual gas (stream 41b). The partially condensed expanded stream 39a is then fed as feed to distillation column 18 at its midpoint.

The demethanizer in column 18 is a conventional distillation column in which several trays with gaps between them, one or more nozzles, or a combination of trays and nozzles are installed. As is often the case with natural gas processing plants, a distillation column may consist of two sections. The upper section 18a is a separator where the top-fed feed containing steam is separated into steam and the liquid component, respectively, and where the steam coming from the bottom rectification or demethanization section 18b is mixed with steam separated from the top-fed feed, resulting in cold helmet steam demethanizer (stream 41), which is discharged from the top of the column at a temperature of -136 ° P [-93 ° C]. The lower section, demethanization section 18b contains trays and / or nozzles and provides the necessary contact between the condensate flowing down and the vapor rising up. Reboilers (such as the reboiler and side reboiler described previously) are also installed in the demethanization section 18b, where part of the condensate draining to the bottom of the column is heated and evaporated to form a stripped vapor rising up the column to distill off the liquid product (stream 44), methane and lighter components.

The liquid product stream 44 leaves the bottom of the column at a temperature of 65 ° P [19 ° C], based on typical requirements for a methane / ethane ratio of 0.010: 1, based on the weight of the bottoms product. The residual gas (helmet steam from demethanizer, stream 41) moves towards the incoming raw gas in the heat exchanger 13, where it is heated to -44 ° P [-42 ° C] (stream 41a), as well as in the heat exchanger 10, where it is heated to 96 ° P [36 ° C] (stream 41b). The residual gas is then subjected to secondary compression in two stages. The first stage is a compressor 16, which is driven by a de-tandem 15232377. The second stage is a compressor 20, which is driven by an additional energy source; here the residual gas (stream 416) is compressed to pressure in the distribution pipeline. After cooling to 120 ° P [49 ° C] in the exhaust cooler 21, the residual gas (stream 41e) enters the sales pipeline at a pressure of 915 psi abs. [6307 kPa (a)], which is sufficient to meet the pressure requirements in the pipeline (usually this is the inlet pressure).

Brief data on consumption and energy consumption for the process shown in FIG. 1 are given in the following table.

Table I (Fig. 1)

Flow data - lb mol / h [kg mol / h]

Methane Ethane Propane Butane Stream + Total

31 12,359 546 233 229 13,726 32 8,404 371 159 155 9,334 33 3,955 175 74 74 4,392 34 12,117 493 172 70 13,196 35 242 53 61 159 530 36 3,829 156 54 22 4,170 38 4,071 209 115 181 4,700 39 8,288 337 118 48 9,026 41 12,350 62 5 one 12,620 44 nine 484 228 228 1.106

Selected Components

Ethane 88.54% Propane 97.70% Bhutans + 99.65%

Power

Residual gas compression 5.174 hp [8506 kW] (Based on non-rounded flow rates)

DETAILED DESCRIPTION OF THE INVENTION

In FIG. 2 is a flow chart of a process in accordance with the present invention. The composition and characteristics of the feed gas taken into account in the process depicted in FIG. 2 are similar to those of FIG. 1. Accordingly, the process depicted in FIG. 2 can be compared with the process in FIG. 1, in order to clearly demonstrate the advantages of the present invention.

When modeling the process according to the circuit shown in FIG. 2, the incoming gas enters the installation in the form of stream 31, which is divided into two streams in the first separation device: stream 32 and stream 33. The first stream, stream 32, enters the first heat exchange device in the upper part of the cooling section of the feedstock 118a, which is located inside the processing plant 118. As the first heat exchanger, a fin heat exchanger, a plate heat exchanger, a brazed aluminum heat exchanger, or another type of heat exchanger, including a multi-pass can be used stems and / or polyfunctional exchangers. This first heat exchanger is designed to provide heat exchange between the stream 32 flowing through one stroke of the heat exchanger and the stripping steam rising from the separation section 118b located inside the processing unit 118, which is heated in the second heat exchange device of the lower part of the raw material cooling section 118a. Stream 32 is cooled, simultaneously heating the stream of stripping steam, while stream 32a leaves the first heat exchanger, having a temperature of -26 ° P [-32 ° C].

The second part of the stream, stream 33, enters the heat and mass transfer device in the demethanization section 1186, which is located inside the processing unit 118. As a heat exchange device, a fin heat exchanger, a plate heat exchanger, a brazed aluminum heat exchanger, or another type of heat exchanger, including multi-pass and / or multi-function heat exchangers. Heat and mass transfer device is intended

- 4 023977 to ensure heat exchange between the stream 33 flowing along one stroke of the heat and mass transfer device and the stripping condensate stream directed downward from the adsorption section 118c (absorption device), which is located inside the processing unit 118; thus, stream 33 is cooled by heating the stripping condensate stream, the temperature of stream 33a drops to -38 ° P [-39 ° C] at the outlet of the heat and mass transfer device. As the flow of the stripping condensate is heated, part of it evaporates and forms stripped vapors, which rise up, while the remaining liquid condensate continues to flow down through the heat and mass transfer device. The heat and mass transfer device provides continuous contact between the stripped vapors and the distillate condensate stream, thereby maintaining mass transfer between the vapor and liquid phases and freeing the liquid product stream 44 from methane and lighter components.

The streams 32a and 33a are recombined in a mixing device and form a stream 31a, which enters the separator section 118e (separation device) located inside the processing unit 118, at a temperature of -30 ° P [-34 ° C] and a pressure of 898 psi abs. [6189 kPa (a)], after which the vapor (stream 34) is separated from the liquid condensate (stream 35). The separation section 118e is separated from the demethanization section 1186 by an internal partition or other means in order to enable the two sections to operate inside processing unit 118 at different pressures.

Steam (stream 34) from separation section 118e is divided into two streams in a second separation device: stream 36 and stream 39. Stream 36, containing about 32% of the total amount of steam, is mixed in an additional mixing device with separated condensate (stream 35, through stream 37 ), and the mixed stream 38 enters the second heat exchange device installed in the lower zone of the cooling section of the raw material 118a, which is located inside the processing unit 118. A heat exchanger made of ribs can also be used as the second heat exchange device ennyh tubes, plate heat exchangers, brazed aluminum heat exchanger or heat transfer device of another type, including a multiport, and / or multifunctional exchangers. The second heat exchange device is designed to provide heat exchange between the stream 38 flowing through one stroke of the heat exchange device and the stripping vapor stream rising from the separation section 118b, so that the stream 38 is cooled to complete condensation, while heating the stripping vapor stream. The resulting condensed stream 38a at a temperature of -130 ° P [-90 ° C], then undergoes rapid evaporation through the first expansion device in the form of expansion valve 14 to an operating pressure (approximately 415 psi [2861 kPa (a)]) section the absorption 118c (absorption device) located inside the processing unit 118. During the expansion process, part of the stream evaporates, as a result of which the main working stream is cooled. In the process illustrated in FIG. 2, the expanded stream 38b after the expansion valve 14 reaches a temperature of -136 ° P [-94 ° C] and is supplied to the separation section 118b inside the processing unit 118. The liquid condensate separated here is sent to the absorption section 118c, and the remaining vapors are mixed with vapors rising from the absorption section 118c, and a stripping steam stream is formed which is heated in the cooling section 118a.

The remaining 68% of the volume of steam from the separation section 118e (stream 39) is supplied to the second expansion device in the form of an expander 15, where the energy of this part of the raw material, which is under high pressure, is converted into mechanical energy. In the expander 15, the vapor undergoes isentropic expansion to the operating pressure of the absorption section 118c, while the expanded stream 39a is cooled to a temperature of about -94 ° P [-70 ° C]. The partially expanded condensed stream 39a is then fed as feed to the lower part of the absorption section 118c inside the processing unit 118.

In the absorption section 118c, several trays are installed with gaps between them, one or more nozzles, or a combination of trays and nozzles. The trays and / or nozzles in the absorption section 118c provide the necessary contact between the vapor rising up and the cold condensate flowing down. The liquid component of the expanded stream 39a is mixed with liquid condensate flowing down from the absorption section 118c, and the mixed condensate enters the condensate collecting device located in the processing unit 118, which allows condensate to drain into the demethanization section 1186. The topped vapors rising from the demethanization section 1186 are mixed with vapors from the expanded stream 39a and then rise to the absorption section 118c, where they come in contact with cold condensate flowing down to condense and absorb the components C ₂ , C ₃ components and heavier components contained in these vapors.

The distillation condensate flowing down from the heat and mass transfer device in the demethanization section 1186 located inside the processing unit 118 is freed from methane and lighter components. The obtained liquid product (stream 44) is removed from the bottom of the demethanization section 1186 and leaves the processing unit 118 at a temperature of 67 ° P [20 ° C]. The steam stream rising from the separation section 118b is collected in a steam collection device located in the processing unit 118 and heated in the cooling section of the feedstock 118a, while cooling the streams 32 and 38 as described previously, and the resulting residual gas stream 41 leaves the processing unit installation 118 at a temperature of 96 ° P [36 ° C]. The residual gas is then re-compressed in two stages: in the compressor 16, which is driven by the expander 15, and in the compressor 2023, which is driven by an additional energy source. After cooling stream 41b to a temperature of 120 ° P [49 ° C] in exhaust cooler 21, the residual gas product (stream 41c) under pressure of 915 psi [6307 kPa (a)] enters the distribution pipeline.

Brief data on consumption and energy consumption for the process shown in FIG. 2 are given in the following table.

Table II (Fig. 2)

Flow data - lb mol / h [kg mol / h]

Flow Methane Ethane Propane Bougans + Total 31 12,359 546 233 229 13,726 32 8,651 382 163 160 9,608 33 3,708 164 70 69 4,118 34 12,139 498 176 74 13,234 35 220 48 57 155 492 36 3,860 158 56 24 4,208 37 220 48 57 155 492 38 4,080 206 113 179 4,700 39 8.279 340 120 fifty 9,026 41 12,350 62 5 one 12,625 44 nine 484 228 228 1,101

Selected Components

Ethane 88.58% Propane 97.67% Bhutan + 99.64%

Power

Residual gas compression 4.829 hp [7,939 kW] (Based on non-rounded flow rates)

Comparison of the table. I and II shows that the present invention allows to provide almost the same level of product recovery as the known technical solutions. However, further comparison of the indicators in the table. I and II shows that the same volume of the finished product was obtained at much lower energy consumption than in a plant assembled using known technical solutions. Regarding the efficiency of product recovery (which is determined by the amount of ethane recovered per unit capacity), the present invention is almost 7% more economical than the process using known technical solutions shown in FIG. one.

The increase in product extraction efficiency provided by the present invention compared to a process based on known technical solutions (Fig. 1) is mainly associated with two factors. Firstly, the compact arrangement of the heat exchangers in the cooling section of the feedstock 118a and the heat and mass transfer devices in the demethanization section 1186 of the processing unit 118 eliminates the pressure drop that occurs due to the presence of connecting piping in a conventional processing unit. As a result, in the installation made in accordance with the present invention, that part of the feed gas that enters the expander 15 is at a higher pressure than the gas in the installation assembled using already known technical solutions; this allows the expander 15 in the circuit of the present invention to produce the same amount of energy at a higher output pressure than the expander 15 produces in the circuit using already known technical solutions, but at a lower output pressure. Therefore, the absorption section 118c in the processing unit 118 of the present invention can operate at a higher pressure than the distillation column 18 in the circuit using already known technical solutions, while the level of product recovery remains the same. The result of an increase in operating pressure and a decrease in pressure drop due to the elimination of connecting pipelines, is that the residual gas enters the compressor 20 at a significantly higher pressure, thereby reducing the amount of energy required to bring the residual gas pressure to a pressure level of the pipeline.

Secondly, the use of heat and mass transfer device in the 118c1 demethanization section for simultaneous heating of the distillation condensate leaving the absorption section 118c, while the resulting steam has the ability to contact with the condensate and release volatile components from it, which is more efficient than using a conventional distillation column with external reboilers. Volatile components are constantly released from the liquid condensate, thereby their concentration in stripped vapors decreases much faster, which increases the efficiency of distillation of light fractions for the present invention.

In addition to increasing the efficiency of processing, the present invention, in comparison with the installations of the current level of technology, has two more advantages. Firstly, the compact design of the processing unit 118 of the present invention replaces five separate pieces of equipment used in the traditional scheme (heat exchangers 10, 11 and 13; separator 12; distillation column 18 in FIG. 1) with one unit (processing unit 118 in FIG. 2 ) At the same time, the area required to accommodate the installation is reduced, and the connecting pipelines are eliminated, which leads to lower capital costs for the processing plant, built according to the scheme of the present invention, in comparison with a plant built using already known technical solutions. Secondly, the exclusion from the design of the connecting pipelines means that the processing plant, constructed according to the scheme of the present invention, has much less flange connections compared to the plant constructed using the well-known technical solutions, which reduces the number of potential leaks in such a plant. Hydrocarbons are volatile organic compounds (VOCs), some of which are classified as greenhouse gases, and some can create holes in the ozone layer; this means that the present invention reduces the possibility of emissions that pollute the atmosphere.

Other embodiments.

In some cases, it may be necessary to remove the cooling section of the feedstock 118a from the processing unit 118 and use external first and second heat exchange devices, for example, heat exchanger 10, as shown in FIG. 10-17. Such a layout scheme allows to reduce the dimensions of the processing unit 118, which will help reduce the total cost of the installation and / or reduce the installation schedule (in some cases). It should be noted that in all cases the heat exchanger 10 is either several separate heat exchangers or one multi-pass heat exchanger, a combination of both options is also possible. Each such heat exchanger can be a finned tube heat exchanger, a plate heat exchanger, a brazed aluminum heat exchanger, or another type of heat exchanger, including a multi-pass and / or multi-function heat exchanger.

In some cases, it may be necessary to supply the liquid condensate stream 35 directly to the lower zone of the absorption section 118c through the stream 40, as shown in FIG. 2, 4, 6, 8, 10, 12, 14 and 16. In this case, the corresponding third expansion device is used (for example, expansion valve 17), where the condensate expands to the operating pressure of the absorption section 118c, and the resulting expanded stream 40a as a raw material fed to the lower zone of the absorption section 118c (as shown by dashed lines). In some cases, it may be necessary to mix part of the liquid stream 35 (stream 37) with steam in stream 36 (Figs. 2, 6, 10 and 14) or with a cooled second stream 33a (Figs. 4, 8, 12 and 16) to form the mixed stream 38 and directing the remaining portion of the condensate stream 35 to the bottom of the absorption section 118c in streams 40 / 40a. In some cases, it may be necessary to mix the expanded condensate stream 40a with the expanded stream 39a (Figs. 2, 6, 10 and 14) or with the expanded stream 34a (Figs. 4, 8, 12 and 16), and then apply the mixed stream to the bottom part of the absorption section 118c as a raw material.

If the residual gas is enriched, then the amount of condensate separated in stream 35 may be sufficient to accommodate an additional mass transfer zone in the demethanization section 1186 between the expanded stream 39a and the expanded condensate stream 40a, as shown in FIG. 3, 7, 11 and 15, or between the expanded stream 34a and the expanded condensate stream 40a, as shown in FIG. 5, 9, 13 and 17. In this case, the heat and mass transfer device in the demethanization section 1186 can be placed in its upper and lower zones, so that the expanded condensate stream 40a is fed into the zone between the two parts of this device. As indicated by dashed lines in the diagram, in some cases it may be necessary to mix part of the liquid stream 35 (stream 37) with steam in stream 36 (Figs. 3, 7, 11 and 15) or with a cooled second stream 33a (Fig. 5, 9 , 13 and 17), for the formation of a mixed stream 38, while the remaining part of the liquid stream 35 (stream 40) expands at a lower pressure and is fed into the zone between the upper and lower parts of the heat and mass transfer device installed in the demethanization section 1186 as stream 40a .

In some cases, it may be necessary not to mix the cooled first and second parts (streams 32a and 33a), as shown in FIG. 4, 5, 8, 9, 12, 13, 16 and 17. In such cases, only the cooled first part, stream 32a, is supplied to the separation section 118e in the processing unit 118 (Figs. 4, 5, 12 and 13) or the separator 12 (Fig. 8, 9, 16 and 17), where the vapor (stream 34) is separated from the liquid condensate (stream 35). The vapor stream 34 enters the expander 15, where it undergoes isentropic expansion to the operating pressure of the absorption section 118c, after which the expanded stream 34a is fed as raw material to the lower part of the absorption section 118c located inside the processing unit 118. The cooled second part of the stream 33a is mixed with the separated a condensate separator (stream 35, through stream 37), and the mixed stream 38 is directed to a heat exchange device at the bottom of the cooling section of the feedstock 118a in the processing unit 118, where it is cooled to full condensation. The condensed stream 38a undergoes rapid evaporation through the expansion valve 14 to the operating pressure of the absorption section 118c, after which the expanded stream 38b is supplied to the separation section 118b located in the processing unit 118. In some cases, it may be necessary to mix only part (stream 37) of the condensate stream 35 with the cooled second part - stream 33 a, and the remaining part (stream 40) to the lower part of the absorption section 118c through the expansion valve 17. In another case, it may be necessary it all the condensate stream 35 to the bottom of the absorption section 118c through an expansion valve 17.

In some cases, it may be necessary to use an external container to separate the cooled feed stream 31a or the cooled first portion — stream 32a, instead of including the gas collection device in the separator section 118e located in the processing unit 118. As shown in FIG. 6, 7, 14 and 15, a separator 12 may be used to separate the cooled feed stream 31a into a steam stream 34 and a condensate stream 35. Also, as shown in FIG. 8, 9, 16 and 17, a separator 12 can be used to separate the cooled portion of stream 32a into steam stream 34 and condensate stream 35.

Depending on the amount of heavy hydrocarbons in the feed gas and its supply pressure, the cooled feed stream 31a entering the separation section 118e, as shown in FIG. 2, 3, 10 and 11, or to a separator 12, as shown in FIG. 6, 7, 14 and 15 (or the cooled first part of the stream 32a entering the separation section 118e, as shown in Figs. 4, 5, 12 and 13, or to the separator 12, as shown in Figs. 8, 9, 16 and 17) may not contain a liquid component (since the pressure exceeds the point of onset of condensation or cricondenbar). In such cases, there is no condensation in streams 35 and 37 (as shown by dashed lines), so that only steam from separation section 118e in stream 36 (FIGS. 2, 3, 10 and 11), steam from separator 12 in stream 36 (FIG. . 6, 7, 14 and 15), or the cooled second part of the stream 33a (Fig. 4, 5, 8, 9, 12, 13, 16 and 17) are poured into the stream 38; this stream turns into an expanded condensed stream 38b entering the separation section 118b located in the processing unit 118. In this case, the separation section 118e in the processing unit 118 (Figs. 2-5 and 10-13) or separator 12 (Fig. 6 -9 and 14-17) may not be needed.

The characteristics of the feed gas, the dimensions of the installation, available equipment or other factors may indicate that it is not necessary to install the expander 15, or it needs to be replaced with another expansion device (for example, an expansion valve). And although the diagram shows specific expansion devices for each stream, if necessary, other devices can be used instead. For example, the processing mode requires the expansion of the fully condensed portion of the feed stream (stream 38a).

In accordance with the present invention, it is possible to use an external cooling unit for additional cooling of the incoming gas entering the streams of distillation steam and condensate, especially if an enriched incoming gas is used. In such a case, heat and mass transfer devices (or gas collection devices if the cooled feed stream 31a or the cooled first portion of stream 32a does not contain a liquid component) can be installed in the separator section 118e, as shown by dashed lines in FIG. 2-5 and 10-13; or heat and mass transfer devices may be installed in the separator 12, as shown by dashed lines in FIG. 6-9 and 14-17. These heat and mass transfer devices can be a finned tube heat exchanger, a plate heat exchanger, a brazed aluminum heat exchanger, or another type of heat exchanger, including multi-pass and / or multi-function heat exchangers. The heat exchange device is designed to provide heat exchange between the flow of the refrigerant (for example, propane), flowing along one stroke of the heat and mass transfer device, and the vaporous part of the stream 31a (Fig. 2, 3,6, 7, 10, 11, 14 and 15) or stream 32a (Figs. 4, 5, 8, 9, 12, 13, 16 and 17), which move upward, while the refrigerant cools the steam and contributes to the formation of additional condensate that flows down and combines with the condensate removed from the stream 35. Alternatively, conventional gas coolers may be used. to lower the temperature of stream 32a, stream 33a, and / or stream 31a with a refrigerant before stream 31a enters separation section 118e (FIGS. 2, 3, 10, and 11) or separator 12 (FIG. 6, 7, 14 and 15); either stream 32a will enter separation section 118e (FIGS. 4, 5, 12, and 13) or to separator 12 (FIGS. 8, 9, 16, and 17).

Depending on the temperature and the degree of enrichment of the feed gas, as well as on the amount of C ₂ components to be removed from the liquid product stream 44, heating by means of stream 33 alone may not be enough for the condensate leaving the demethanization section 1186 , met the requirements for product specifications. In this case, additional heating means can be installed in the heat and mass transfer device in the demethanization section 1186 using a heat carrier, as shown by dashed lines in FIG. 2-17. Alternatively, it is possible to install another heat and mass transfer device in the lower part of the demethanization section 1186 to provide additional heating; or stream 33 can be heated using a heat carrier before it enters the heat and mass transfer device installed in the demethanization section 1186.

Depending on the type of heat transfer devices selected as heat exchangers for the upper and lower parts of the raw material cooling section 118a, it is possible to combine these heat exchangers into one multi-pass and / or multi-function heat exchanger. In this case, the multi-pass and / or multi-function heat exchanger should have appropriate means for distributing, separating and collecting stream 32, stream 38, and also the stripping steam stream, in order to heat or cool to the desired level.

In some cases, it may be necessary to install an additional heat and mass transfer device in the upper part of the demethanization section 1186. In this case, the heat and mass transfer device can be placed below the feed point of the expanded flow 39a (Figs. 2, 3, 6, 7, 10, 11, 14 and 15) or extended stream 34a (FIGS. 4, 5, 8, 9, 12, 13, 16 and 17) to the lower part of the absorption section 118c, and above the exit point of the cooled second part of the stream 33a from the heat and mass transfer device in the demethanization section 1186. Less preferred for the embodiments of the present invention shown in FIG. 2, 3, 6, 7, 10, 11, 14, and 15, is the installation of a separator for the cooled first part of the stream 32a, a separator for the cooled second part of the stream 33a; wherein the steam streams separated in the separators are mixed to form a steam stream 34, and the condensate streams are mixed and form a condensate stream 35. Another less preferred embodiment of the present invention is to supply a cooling stream 37 through a separate heat exchanger located in the cooling section of the feedstock 118a in FIG. 2, 3, 4, 5, 6, 7, 8, and 9, or through a separate stream in the heat exchanger 10 in FIG. 10, 11, 12, 13, 14, 15, 16, and 17 (instead of mixing stream 37 with stream 36 or stream 33a to form a combined stream 38); wherein the expansion of the cooled stream is carried out in a separate expansion device, and the expanded stream is supplied to the intermediate part of the absorption section 118c.

It should be noted that the relative amount of raw materials in each branch of the separated vaporous raw materials depends on several factors, including the pressure and composition of the raw gas, the amount of heat that can be extracted from the raw material, as well as the available amount of power. An increase in the supply of raw materials to the zone above the absorption section 118c can lead to an increase in the degree of product recovery with a decrease in the power obtained in the expander, which, in turn, leads to an increase in the power required for re-compression of the product. An increase in the supply of raw materials to the zone below the absorption section 118c reduces the level of power consumption, but the level of product recovery may also decrease. The present invention provides an increased degree of extraction of components C ₂ , C ₃ and more heavy hydrocarbons or components C ₃ and more heavy hydrocarbons by the amount of auxiliary media consumed necessary for the functioning of the process. The saving of consumed auxiliary media necessary for the functioning of the process can be manifested in the form of a decrease in power consumption for compression or re-compression; reducing the power needed for an external cooling installation; reduction of energy required for additional heating; or in the form of a combination thereof.

Described here are preferred embodiments of the invention; specialists with an appropriate level of technical training can find other options or make changes to those described here (for example, adapt the invention to work in other modes, using a different type of raw material or with changing other requirements), without deviating from the essence of the present invention defined in its next formula.

Claims (26)

CLAIM 1. A method of separating a gas stream (31) containing methane, components C ₂ , components C ₃ and heavier hydrocarbon components, into a volatile fraction (416) of residual gas and a relatively less volatile fraction (44) containing the bulk of these components C2, components C3 and heavier hydrocarbon components or the specified components C3 and heavier hydrocarbon components, while: (a) said gas stream (31) is divided into first (32) and second (33) parts; (b) said first portion of stream (32) is cooled (10); (c) said second portion of stream (33) is cooled (1186); (6) said chilled first portion of stream (32a) is mixed with said chilled second portion of stream (33a), thereby forming a stream of chilled gas (31a), (34); - 9 023977 (e) said gas stream (31a), (34) is divided into first (36) and second (39) streams; (ί) said first stream (36) is cooled (10) to its almost complete condensation (38a), and then expanded (14) to a lower pressure, due to which it is cooled even more (38b); (e) said expanded and cooled first stream (38b) is supplied as raw material to the upper part of the absorption device, which is located inside the processing unit (118) in the absorption section (118c); (H) said second stream (39) is expanded (15) to a lower pressure (39a) and fed as a feed to the bottom of said absorption device; (ί) a stripping steam stream (41) is taken from the upper part of said absorption device, which is heated in one or more heat exchange devices (10), thereby providing at least partial cooling in steps (b) and (ί) of the method according to Claim 1, and then said heated stripping vapor stream (41a) is withdrawn from the installation as said volatile residual gas fraction (416); (ί) a stream of distillation condensate is taken from the bottom of said absorption device, which is heated in a heat and mass transfer device located in said processing unit (118) in the demethanization section (1186); thereby providing at least partial cooling in step (c), while more volatile components are freed from said condensate stream, after which said heated and purified from light fractions distillation condensate stream is removed from processing unit (118) as a less volatile fraction (44); (k) the amount and temperature of said feed streams (38b), (39a) sent to the absorption device are sufficient to maintain the temperature at the top of said absorption device at which the bulk of said less volatile components are removed from the stream (44). 2. The method according to claim 1, in which: (a) said cooled first portion of stream (32a) is mixed with said cooled second portion of stream (33a), thereby forming a partially condensed gas stream (31a); (b) said partially condensed gas stream (31a) is supplied to a separation device (12), where it is separated into a vapor stream (34) and at least one condensate stream (35); (c) said vapor stream (34) is divided into said first (36) and second (39) streams; (6) at least a portion (40) of said at least one condensate stream (35) is expanded (17) to a lower pressure and is supplied (40a) as additional raw material to the lower part of said absorption device. 3. The method according to claim 2, in which: (a) said first stream (36) is mixed with at least a portion (37) of a liquid of said at least one stream of condensate (35) to form a mixed stream (38); (b) said mixed stream (38) is cooled (10) until it is almost completely condensed (38a), and then expanded (14) to a lower pressure, due to which it is cooled even more (38b); (c) said expanded and cooled mixed stream (38b) is supplied as said feed to the top of the absorption device; (6) the remaining part (40) of said at least one condensate stream (35) is expanded (17) to a lower pressure and (40a) is supplied as said additional feed to the lower part of said absorption device; (e) the specified stream of stripping steam (41) is heated in one or more heat exchange devices (10), thereby providing at least partial cooling in steps (b) of the methods according to claims 1 and 3. 4. The method according to claim 1, in which: (a) said first portion of the stream (32) is cooled (10) and then expanded (15) to the indicated lower pressure; (b) said expanded and cooled first portion of the stream (34a) is supplied as said raw material to the bottom of the absorption device; (c) said second part of the stream (33) is cooled (1186), (10) to an almost complete condensation (38a), and then it is expanded (14) to the indicated lower pressure, due to which it is cooled even more (38b); (6) said expanded and cooled second part of the stream (38b) is supplied as said raw material to the upper part of the absorption device; (e) a stripping steam stream (41) is taken from the upper part of said absorption device, which is heated in one or more heat exchange devices (10), thereby providing at least partial cooling in steps (a) and (c) of this method ; (ί) from the lower part of the specified absorption device, a specified stream of distillation condensate is taken, which is heated in a heat and mass transfer device, which is located inside the processing unit (118) in the demethanization section (1186), thereby providing at least partial cooling in step ) of this method. 5. The method according to claim 4, in which: - 10 023977 (a) said first part of the stream (32) is cooled (10) until it partially condenses (32a); (b) said partially condensed (32a) first portion of the stream is fed to a separation device (12), where it is separated into a vapor stream (34) and at least one condensate stream (35); (c) said vapor stream (34) is expanded (15) to a lower pressure and is supplied as said raw material (34a) to the bottom of the absorption device; (6) at least a portion (40) of said at least one condensate stream (35) is expanded to said lower pressure and supplied as additional feed (40a) to the lower part of said absorption device. 6. The method according to claim 5, in which: (a) said second part (33) of the stream is cooled (1186) and then mixed with at least part (37) of the liquid from said at least one condensate stream (35) to form a mixed stream (38); (b) said mixed stream (38) is cooled (10) until it is almost completely condensed (38a), and then it is expanded (14) to the indicated lower pressure, due to which it is cooled even more (38b); (c) said expanded and cooled mixed stream (38b) is supplied as said feed to the top of the absorption device; (6) the remaining part (40) of said at least one condensate stream (35) is expanded (17) to the indicated lower pressure and fed as said additional feed (40a) to the lower part of said absorption device; (e) the stripping steam stream (41) is heated in one or more heat exchange devices (10), thereby providing at least partial cooling in steps (a) of the method according to claims 4 and 5 and in step (b) of the method according to to this item. 7. The method according to claim 2 or 5, characterized in that: (a) said heat and mass transfer device is located in the upper and lower zones of the demethanization section (1186); (b) said expanded portion of said at least one of the condensate streams (40a) is supplied to said processing unit (118), into the space between said upper and lower zones. 8. The method according to claim 3 or 6, characterized in that: (a) said heat and mass transfer device is located in the upper and lower zones of the demethanization section (1186); (b) said expanded remainder of said at least one of the condensate streams (40a) is supplied to said processing unit (118), into the space between said upper and lower zones. 9. The method according to PP.2, 3, 5-7 or 8, characterized in that the separation device is located in the specified processing unit (118) in the separator section (118e). 10. The method according to claim 1, characterized in that: (a) a gas collection device is located in said processing unit (118) in a separator section (118e); (b) an additional heat and mass transfer device is placed inside said gas collection device, said additional heat and mass transfer device having one or more channels for passing an external cooling agent; (c) said chilled gas stream (31a) is supplied to said gas collecting device and sent to said additional heat and mass transfer device, where it is further cooled by said external cooling agent; (6) said cooled gas stream (34) is divided into first (36) and second (39) streams. 11. The method according to claim 4, characterized in that: (a) a gas collection device is located in said processing unit (118) in a separator section (118e); (b) an additional heat and mass transfer device is placed inside said gas collection device, said additional heat and mass transfer device having one or more channels for passing an external cooling agent; (c) said chilled first portion of stream (32a) is supplied to said gas collecting device and sent to said additional heat and mass transfer device, where it is further cooled by said external cooling agent; (6) the specified cooled first part of the stream (34) is expanded (15) to the specified lower pressure, and then it is served as the specified feedstock (34a) in the lower part of the specified absorption device. 12. The method according to PP.2, 3, 5-8 or 9, characterized in that: (a) inside the separation device (12) an additional heat and mass transfer device is placed, wherein said additional heat and mass transfer device has one or more channels for - 11 023977 passage of an external cooling agent; (b) said vapor stream is directed to said additional heat and mass transfer device, where it is cooled by an external cooling agent to form additional condensate; (c) said condensate is poured into said at least one of the condensate streams (35) separated by separation. 13. The method according to claims 1-11 or 12, characterized in that in said heat and mass transfer device located in the demethanization section (1186), there is one or more channels for an external heat carrier to supplement the heating provided by the feed gas (33) to a level that is sufficient to separate more volatile components from the specified stream of distillation condensate. 14. Installation for implementing the method of separating a gas stream (31) containing methane, components C ₂ , components C ₃ and heavier hydrocarbon components, into a volatile fraction of residual gas (416) and a relatively less volatile fraction (44) containing the bulk of these components C2, components C3 and heavier hydrocarbon components, or said components C ₃ and heavier hydrocarbon components according to claim 1, including: (a) a first separation device for separating the gas stream (31) into a first (32) and a second (33) part; (b) a first heat exchange device (10) connected to said first separation device for receiving and cooling the first part of the stream (32); (c) a heat and mass transfer device installed in the processing unit (118) in the demethanization section (1186) and connected to the first separation device, for receiving and cooling the second part of the stream (33); (6) a mixing device connected to said first heat exchange device (10) and to said heat and mass transfer device, for mixing the cooled first (32a) and second (33a) parts of the stream and the formation of the cooled gas stream (31a), (34); (e) a second separation device connected to said mixing device for receiving a cooled gas stream (31a), (34) and separating it into first (36) and second (39) streams; (ί) a second heat exchange device (10) connected to said second separation device for receiving the first stream (36) and cooling it to almost complete condensation (38a); (e) a first expansion device (14) connected to said second heat exchange device (10), for receiving a fully condensed stream (38a) and expanding it to a lower pressure (38b); (i) an absorption device located in said processing unit (118) in the absorption section (118c) and connected to the first expansion device (14), designed to receive the expanded cooled first stream (38b) in its upper part as raw material; (ί) a second expansion device (15) connected to said second separation device for receiving a second stream (39) and expanding it to said reduced pressure (39a); moreover, the specified expansion device (15) is additionally connected to the specified absorption device for supplying the expanded second stream (39a) in its lower part as a raw material; (ί) a steam collection device located in a processing unit (118) in a separator section (118b) and connected to said absorption device, for receiving a stream of stripping steam coming from the upper part of said absorption device; (k) said second heat exchange device (10) is further connected to said steam collection device and is adapted to receive and heat said stripping steam stream (41), thereby providing at least partially cooling in step (ί) of the method according to claim 1 ; (l) said first heat exchanger (10) is further connected to a second heat exchanger (10) for receiving and further heating said distillate vapor stream (41), thereby providing at least partially cooling in step (b) of the method according to claim .1, after which the specified stream of stripping steam (41a) is withdrawn from the installation in the form of the specified volatile fraction of the residual gas; (t) a condensate collecting device located in the processing unit (118) and connected to said absorption device, for receiving a stream of distillation condensate coming from the bottom of said absorption device; (p) the specified heat and mass transfer device is additionally connected to the specified condensate collection device for receiving and heating the specified stream of distant condensate, thereby providing at least partially cooling in step (c) of the method according to claim 1, while simultaneously from the stream of distant condensate more volatile components are released, after which the specified distilled condensate stream heated and freed from light fractions is removed from the processing unit (118) as the indicated relatively less volatile fraction and (44); - 12 023977 (o) a control device designed to control the amount and temperature of the specified feed streams (38b), (39a) sent to the specified absorption device, to maintain the temperature in the upper part of this absorption device at a level at which the main a portion of said fraction (44) of less volatile components. 15. The installation according to 14, in which: (a) said mixing device is adapted to receive and mix the cooled first (32a) and second (33a) parts of the stream and form a partially condensed gas stream (31a); (b) a separation device (12) is connected to said mixing device and is adapted to receive a partially condensed gas stream (31a) and to separate it into a vapor stream (34) and at least one liquid condensate stream (35); (c) a second separation device is connected to the specified separation device (12) and is designed to receive the specified vapor stream (34) and its separation into the first (36) and second (39) streams; (6) the third expansion device (17) is connected to the specified separation device (12) and is designed to receive at least part (40) of the specified at least one stream of condensate (35) and its expansion to the specified reduced pressure, and the specified third expansion device (17) is additionally connected to said absorption device for supplying said expanded at least part (40a) of liquid condensate to its lower part as additional raw materials. 16. The installation according to clause 15, in which: (a) an additional mixing device is connected to the specified second separation device and the separation device (12) and is designed to receive the first stream (36) and at least part (37) of the specified at least one condensate stream (35) and the formation of a mixed stream ( 38); (b) said second heat exchange device (10) is connected to said additional mixing device for receiving the mixed stream (38) and cooling it until it is almost completely condensed (38a); (c) said first expansion device (14) is connected to said second heat exchange device (10) and is intended to receive an almost completely condensed mixed stream (38a) and expand it to a lower pressure (38b); (6) the specified absorption device is connected to the first expansion device (14) for receiving the expanded cooled mixed stream (38b) in its upper part as a raw material; (e) said third expansion device (17) is connected to said separation device (12) for receiving any remaining part (40) of said at least one condensate stream (35) and expanding it to said reduced pressure (40a), said third an expansion device (17) is additionally connected to said absorption device for supplying to its lower part an expanded any remaining part (40a) of said at least one condensate stream as said additional raw material; (D) the specified second heat exchange device (10) is additionally connected to the specified steam collection device and is designed to receive and heat the specified stream of stripping steam (41), thereby providing at least partially cooling in step (b) of the method according to claim 3 . 17. The installation according to 14, in which: (a) said second heat exchange device (10) is connected to said heat and mass transfer device and is intended to receive a cooled second part of the stream (33 a) and to further cool it to almost complete condensation (38a); (b) said first expansion device (14) is connected to said second heat exchanger device (10) and is designed to receive a substantially completely condensed second part of the stream (38a) and expand it at a lower pressure (38b); (c) said absorption device is connected to a first expansion device (14) and is intended to receive an expanded cooled second part of the stream (38b) in its upper part as raw material; (6) said second expansion device (15) is connected to said first heat exchanger device (10) and is designed to receive a cooled first part of the stream (32a) and expand it to said reduced pressure (34a), said second expansion device (15) additionally connected to the specified absorption device for supplying in its lower part of the expanded first part of the stream (34a) as a raw material; (e) said second heat exchange device (10) is additionally connected to said steam collection device and is intended to receive and heat said stream of stripping steam (41), thereby providing at least partially cooling in step (a) of the method according to claim 4 . 18. Installation according to 17, in which: (a) the first heat exchange device (10) is adapted to receive said first part of the flux 13 023 977 ka (32) and to cool it until it is almost completely condensed (32a); (b) a separation device (12) is connected to said first heat exchange device (10) and is intended to receive a partially condensed first part of the stream (32a) and to separate it into a vapor stream (34) and at least one liquid condensate stream (35); (c) a second expansion device (15) is connected to the specified separation device (12) and is designed to receive and expand the specified vapor stream (34) to the specified reduced pressure (34a), and the specified second expansion device (15) is additionally connected to the specified device absorption for feeding into its lower part of the specified expanded vapor stream (34a) as the specified raw material; (b) a third expansion device (17) is connected to the specified separation device (12) and is intended to receive at least part (40) of the specified at least one stream of condensate (35) and its expansion to the specified reduced pressure (40a), and said third expansion device (17) is further connected to said absorption device for supplying at least a portion (40a) of said expanded single condensate stream to its lower part as additional raw materials. 19. The installation according to p, in which: (a) a mixing device is connected to said heat and mass transfer device and a separation device (12) and is designed to receive a cooled specified second part of the stream (33 a) and at least part (37) of the specified at least one condensate stream (35) and the formation of mixed flow (38); (b) said second heat exchange device (10) is connected to said mixing device and is intended to cool the mixed stream (38) until it is almost completely condensed (38a); (c) said first expansion device (14) is connected to said second heat exchange device (10) for receiving said substantially completely condensed mixed stream (38a) and expanding it to a lower pressure (38b); (b) said absorption device is connected to a first expansion device (14) and is intended to receive an expanded cooled mixed stream (38b) in its upper part as said raw material; (e) said third expansion device (17) is connected to said separation device (12) and is intended to receive any remaining part (40) of said at least one condensate stream (35) and expand it to said reduced pressure (40a), wherein the specified third expansion device (17) is additionally connected to the specified absorption device for supplying in its lower part of the specified expanded at least part (40A) of the specified at least one condensate stream as specified additionally go raw materials; (ί) said second heat exchange device (10) is additionally connected to said steam collection device and is intended for receiving and heating said stream of stripping steam (41a), thereby providing at least partially cooling in step (b) of the method according to claim 6 . 20. Installation according to item 15 or 18, characterized in that: (a) said heat and mass transfer device is installed in the upper and lower zones of the demethanization section (118b); (b) said processing unit (118) is connected to a third expansion device (17) for receiving said expanded at least part of said at least one condensate stream (40a) and directing it to the zone between said upper and lower zones where said heat and mass transfer device. 21. Installation according to item 16 or 19, characterized in that: (a) said heat and mass transfer device is installed in the upper and lower zones of the demethanization section (118b); (b) said processing unit is connected to a third expansion device (17) for receiving any remaining portion of said at least one expanded condensate stream (40a) and directing it to the zone between said upper and lower zones where said heat and mass transfer device is installed. 22. Installation according to claims 15, 16, 18-20 or 21, characterized in that the separation device is located in said processing unit (118) in the separator section (118e). 23. Installation according to 14, characterized in that: (a) a gas collection device is located in said processing unit (118) in a separator section (118e); (b) inside said gas collection device, an additional heat and mass transfer device is disposed, said heat and mass transfer device having one or more channels for passing an external cooling agent; (c) said gas collecting device is connected to said mixing device for receiving a cooled gas stream (31a) and for directing it to said additional heat and mass transfer device for further cooling with said external cooling agent; (ά) said second separation device is connected to said gas collecting device for receiving a cooled gas stream (34) and for separating it into first (36) and second (39) streams. 24. Installation according to claim 17, characterized in that: (a) a gas collection device is located in said processing unit (118) in a separator section (118e), (b) an additional heat and mass transfer device is arranged inside said gas collection device, said heat and mass transfer device having one or more channels for passing an external cooling agent; (c) said gas collection device is connected to a first heat exchange device (10) for receiving a cooled first part of the stream (32a) and for its direction to said additional heat and mass transfer device for further cooling with an external cooling agent; (ά) a second expansion device (15) is connected to said gas collecting device for receiving said additionally cooled first part of the stream (34) and expanding it to said reduced pressure (34a), said second expansion device (15) being additionally connected to said absorption device for supplying to its lower part of said expanded and further cooled first part of the stream (34a) as said raw material. 25. Installation according to claims 15, 16, 18-21 or 22, characterized in that an additional heat and mass transfer device is placed inside the separation device (12), said additional heat and mass transfer device having one or more channels for passing an external cooling agent to cool said a vaporous stream until additional condensate forms when passing through said additional heat and mass transfer device; and pouring said condensate into said at least one condensate stream (35) separated by separation. 26. Installation according to claims 14-24 or 25, characterized in that in said heat and mass transfer device located in the demethanization section (118ά), there is one or more channels for an external heat carrier to supplement the heating provided by said second part of the flow ( 33) to a level sufficient to separate more volatile components from the specified stream of distillation condensate.