KR101758394B1 - Hydrocarbon gas processing - Google Patents

Abstract

Apparatus and methods are disclosed for a compact processing assembly for recovering propane, propylene, and heavy hydrocarbon components from a hydrocarbon gas stream. The gas stream is cooled, expanded to a lower pressure, and supplied to the absorption means. The first distillation liquid stream from the absorption means is fed to heat and mass transfer means. The first distillation vapor stream from the mass transfer means is cooled to partially condense it and forms a condensed stream with the residual vapor stream. The condensed stream is supplied as an upper feed to the absorption means. The second distillation vapor stream from the absorption means is heated by cooling the first distillation vapor stream, combined with the residual vapor stream, and heated by cooling the gas stream. The second distillation liquid stream from the mass transfer means is heated in the heat and mass transfer means to strip the volatile components.

Description

[0001] HYDROCARBON GAS PROCESSING [0002]

Propane, propane and / or heavier hydrocarbons may be used as syngas streams obtained from other hydrocarbon materials such as coal, crude oil, naphtha, oil shale, tar sands and lignite, refinery gases gas, natural gas, and the like. Natural gas usually has mainly methane and ethane as main components, that is, methane and ethane together make up at least 50 mole percent of the gas. Natural gas contains relatively small amounts of heavy hydrocarbons such as propane, butane, pentane, etc., as well as hydrogen, nitrogen, carbon dioxide and other gases.

The present invention generally relates to the recovery of propylene, propane and heavier hydrocarbons from such a gas stream. Typical analytical values of the gas stream to be treated in accordance with the present invention are 88.4% methane, 6.2% ethane and other C ₂ components, 2.6% propane and other C ₃ components, 0.3% isobutane, 0.5% Butane and 0.8% pentane, and nitrogen and carbon dioxide as mass. Often there are gases containing sulfur.

Historically, periodic price fluctuations of natural gas and its liquefied natural gas (NGL) components have reduced the value of heavier components and propane and propylene as liquid products. This has led to a demand for a more efficient way to recover these products and to provide an efficient recovery with less capital investment. Methods available for the separation of these materials include methods based on cooling and freezing of the gas, absorption of oil and absorption of freezing oil. In addition, cryogenic processes are becoming commonplace because of the availability of economical devices that simultaneously produce power while expanding and recovering heat from the treated gas. Depending on the pressure of the gas source, the richness of the gas (ethane, ethylene and heavy hydrocarbon content) and the desired end product, each or a combination of these processes can be used.

A cryogenic expansion process is currently generally preferred for the recovery of natural liquefied gas because it provides maximum simplicity with ease of start-up, stretchability of operation, high efficiency, stability and excellent reliability . U.S. Patent 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; 5,771,712; 5,799,507; 5,881,569; 5,890,378; 5,983,664; 6,182,469; 6,578,379; 6,712,880; 6,915,662; 7,191,617; 7,219,513; Reissue United States Patent No. 33,408; Co-pending application Serial No. 11 / 430,412; 11 / 839,693; 11 / 971,491; 12 / 206,230; 12 / 689,616; 12 / 717,394; 12 / 750,862; 12 / 772,472; 12 / 781,259; 12 / 868,993; 12 / 869,007; 12 / 717,394; 12 / 750,862; 12 / 772,472; 12 / 781,259; 12 / 868,993; 12 / 869,007; 12 / 869,139; 12 / 979,563; And 13 / 048,315 disclose processes related thereto. (Although the description of the invention is based in some cases on other process conditions than those described in the above-cited U.S. Patents).

In a typical cryogenic expansion recovery process, the gas stream fed under pressure is cooled by heat exchange with an external cooling source, such as another stream of the process and / or a propane compression-cooling system. As the gas cools, the liquid condenses and can be collected in one or more separators as a high pressure liquid containing some of the desired < _{RTI ID = 0.0} > C < / RTI & Depending on the richness of the gas and the amount of liquid formed, the high pressure liquid can be expanded to low pressure and fractionally distilled. Evaporation occurring in the expansion phase of the liquid results in additional cooling of the stream. Under certain conditions, it may be desirable to pre-cool the high-pressure liquid prior to expansion to further lower the temperature due to expansion. The expanded stream, consisting of a mixture of liquid and vapor, is fractionally distilled in a distillation [deethanizer] column. In this column, the expanded cooled stream (s) are distilled to produce methane, C ₂ components, which remain as overhead vapors from desired C ₃ components and heavy hydrocarbon components as a bottom liquid product, Nitrogen and other volatile gases.

If the feed gas is not completely condensed (generally not), the remaining vapor as a result of partial condensation is condensed by additional expansion of the stream through a work expansion machine or engine, or an expansion valve Pressure side. The expanded stream then enters the absorption section of the tower and is contacted with the cooled liquids to absorb C ₃ components and heavier components from the vapor portion of the expanded stream. Liquids from the absorption section are then sent to the deethanizer section of the tower.

The distillation vapor stream is withdrawn from the top of the deethanizer section and is cooled in heat exchange relationship with the overhead vapor stream from the absorption section and condenses at least a portion of the distillation vapor stream. The condensed liquid is separated from the cooled distillation vapor stream to produce a cooled liquid reflux stream which is sent to the top of the absorption section where the cooled liquids can be contacted with the vapor portion of the expanded stream as described above have. The overhead vapor from the absorption section and the vapor portion (if present) of the cooled distillation vapor stream are combined to form a residual methane and C ₂ component product gas.

(Which comprises essentially all of the C ₃ and C ₂ components in the feed gas and essentially leaving out the process that does not essentially contain C ₃ components and heavy hydrocarbon components and essentially all of the C ₃ and heavy hydrocarbon components Separation that takes place in this process, which produces a lower portion that is essentially free of methane and C ₂ components or more volatile components, is advantageous for feed gas cooling, for refluxing the deethanizer absorbing section, And / or consumes energy to recompress the residual gas.

The present invention utilizes the novel means of performing the various steps described above more efficiently and with fewer devices. This is accomplished by incorporating what was previously individual devices into a common housing thereby reducing the space required for the treatment plant and reducing the capital cost of the facility. Surprisingly, applicants have found that a more compact arrangement also significantly reduces the power consumption required to achieve a certain recovery level, thereby increasing process efficiency and reducing facility operating costs. In addition, a more compact arrangement eliminates much of the piping used to connect individual devices to each other in a conventional plant design, further reducing investment costs and also eliminating the associated flanged pipeline connections. Since pipe flanges are a potential source of leaks in hydrocarbons (volatile organic compounds (VOCs) that can cause greenhouse gases and may also be precursors to atmospheric ozone formation), removal of these flanges can lead to environmental destructive atmospheric emissions Thereby reducing the potential of

In accordance with the present invention, C ₃ recovery in excess of 99.6% can be obtained, and C ₂ It has been found that it provides an essentially complete elimination of the components. The present invention also allows essentially 100% separation of C ₂ components and lighter components from C ₃ components and heavier components under lower energy requirements than the prior art while maintaining the same recovery level. The present invention is based on the assumption that even though it is applicable at lower pressures and at warmer temperatures, the present invention is advantageous in the range of 400 to 1500 psia [2,758 to 10,342 kPa (a) )] Is particularly beneficial when treating feed gases of overpressure.

For a better understanding of the present invention, reference is made to the following examples and figures:
1 is a flow diagram of a prior art natural gas processing plant according to U.S. Patent No. 5,799,507;
2 is a flow chart of a natural gas processing plant according to the present invention;
Figures 3 through 21 are flow charts illustrating alternative means of applying the present invention to a natural gas stream.

In the following description of the figures, tables are provided to summarize flow rates calculated for representative process conditions. In the tables shown here, the values for flow rates (moles per hour) are rounded to the nearest integer for convenience. The overall stream rates presented in the tables are generally greater than the sum of the stream flow rates for the hydrocarbon components since they include all non-hydrocarbon components. The indicated temperatures are approximate values rounded to the nearest degree. It should be appreciated that the process design calculations performed to compare the processes illustrated in the Figures are based on the assumption that there is no heat leakage from the process to or from the process or from the process to the environment. The quality of commercially available insulating materials makes this a very reasonable assumption and is typically assumed by those skilled in the art.

For convenience, process variables are reported in both the traditional UK system and the International System of Units (SI). The molar flow rates given in the tables can be interpreted as either pound moles per unit time or kilogram moles per hour. The energy consumption recorded in horsepower (HP) and / or British thermal units per hour (MBTU / Hr) corresponds to the stated molar flow rate of pound molar per hour. The energy consumption recorded in kilowatts (kW) corresponds to the stated molar flow rate in kilograms per hour.

Description of the Prior Art

1 is a process flow diagram showing the design of a treatment plant for recovering C ₃ + components from natural gas using the prior art according to US 5,799,507. In this process simulation, the incoming gas enters the plant as a stream 31 at a temperature of 110 ° F [43 ° C] and a pressure of 885 psia [6,100 kPa (a)]. If the incoming gas contains a certain concentration of sulfur compounds that prevent the product streams from meeting the specification, the sulfur compounds are removed by an appropriate pretreatment of the feed gas (not shown). Also, the feed stream is dehydrated to prevent hydrate (ice) formation generally under cryogenic conditions. Solid desiccants have typically been used for this purpose.

The feed stream 31 is fed to the distillation column 40 through the remaining gas (stream 44), flash expanded separator liquids (stream 35a) and distillation liquids (stream 43) cooled in heat exchanger 10, -76 < 0 > C]. The cooled stream 31a enters the separator 11 at a temperature of -34 ° F [-36 ° C] and a pressure of 875 psia [6,301 kPa (a)] where the vapor (stream 34) 35). The separator liquid (stream 35) is expanded by the expansion valve 12 to a pressure slightly higher than the operating pressure of the fractionation tower 15 (about 375 psia [2,583 kPa (a) Cool to a temperature of -65 ° F [-54 ° C]. Stream 35a enters heat exchanger 10 and provides cooling to the feed gas as described above and provides stream 35b at 105 占 [[41 占 폚 (占 폚) before being fed to fractionation tower 15 at the lower mid- Lt; / RTI >

The steam (stream 34) from the separator 12 enters the work expansion device 13 where the mechanical energy is extracted from this portion of the high pressure feed. The device 13 expands the steam substantially isentropically to the working pressure of the fractionation tower 15 and the work expansion cools the expanded stream 34a to a temperature of about -100 ° F [-74 ° C]. Typical commercial expanders can be recovered to as much as 80-85% of the theoretically possible in ideal isentropic expansion. The recovered work is often used to drive a centrifuge compressor (such as item 14) that can be used to recompress the heated residual gas (stream 44a). The partially condensed expanded stream 34a is then fed as feed to the upper mid-column feed point.

The deethanizer of the fractionation tower 15 is a conventional distillation column comprising a plurality of vertically spaced trays, one or more packed beds, or some combination of trays and packed beds. The deethanizer tower is composed of two sections: the necessary contact between the vapor portion of the upwardly rising expanded stream 34a and the cooled liquid falling down to condense and absorb the C ₃ components and heavy components An upper absorption (rectification) section 15a including trays and / A lower stripping section (15b) comprising trays and / or filling layers to provide the necessary contact between liquids falling down and vapors rising upward. The deethanizer section 15b also includes one or more reboilers (such as reboiler 16) which are adapted to strip the liquid product (stream 37) of methane, C ₂ components and lighter components A portion of the liquid descending the tower is heated and evaporated to provide stripping vapors that climb up the tower. The stream 34a enters the deethanizer 15 at a mid-column feed position located below the absorption section 15a of the deethanizer 15. The liquid portion of the expanded stream 34a is mixed with the liquid falling down from the absorption section 15a and the combined liquid continues to go down to the stripping section 15b of the deethanizer absorber 15. [ The vapor portion of the expanded stream (34a) rises up through the absorption section (15a) and contacts the cooled liquid falling down to condense and absorb the C ₃ components and heavy components.

A portion of the distillation vapor (stream 38) is recovered from the top of the stripping section 15b. This stream is then cooled and partially condensed in a heat exchanger 17 with a cooled deethanizer overhead stream 36 leaving the top of the deethanizer at a temperature of -109 ° F [-79 ° C] (stream 38a). The cooled deethanizer overhead stream is cooled to about -33 ° F [-35 ° C] when cooling stream 38 to a temperature of about -103 ° F [-75 ° C] (stream 38a) at a temperature of -30 ° F [ -66 < 0 > C) (stream 36a).

The working pressure of the reflux separator 18 is maintained at a pressure slightly lower than the working pressure of the deethanizer 15. This pressure difference provides a driving force that causes the distillation vapor stream 38 to flow through the heat exchanger 17 to the reflux separator 18 where the condensed liquid ). The unconcentrated vapor stream 39 is combined with the deethanizer overhead stream 36a warmed from the exchanger 17 to form a cooled residual gas stream 44 at -37 ° F [-38 ° C].

The liquid stream 40 from the reflux separator 18 is extruded by the pump 19 at a pressure slightly above the working pressure of the deethanizer 15. The resulting stream 40a is then divided into two parts. The first portion (stream 41) is fed as a cooled top column feed (reflux) to the top of the absorption section 15a of the deethanizer absorber 15. [ This cooled liquid causes the absorption cooling effect to take place in the absorption (rectification) section 15a of the deethanizer absorber 15 where it is evaporated from the liquid methane and ethane contained in the stream 41, Saturation of rising vapors provides cooling in this section. As a result, both the liquid (distillation liquid stream 43) leaving the bottom of the absorption section 15a and the vapor leaving the top (top stream 36) And stream 34a). ≪ / RTI > This absorption cooling effect allows the tower tops (stream 36) to provide the necessary cooling to the heat exchanger 17 so that it does not operate the stripping section 15b at significantly higher pressure than in the absorption section 15a, Stream 38). ≪ / RTI > This absorption cooling effect also helps the condensation and absorption of the C ₃ components and heavy components of the distillation vapor where the reflux stream 41 flows up through the absorption section 15a. The second portion of the extruded stream 40a (stream 42) is fed to the top of the stripping section 15b of the deethanizer absorber 15 where the cooled liquid is passed through the distillation vapor stream 38, the acts as reflux to condense and absorb the flow C ₃ components and heavier components from the bottom to contain.

The distillation liquid stream 43 from the deethanizer 15 is recovered from the bottom of the absorption section 15a and sent to the heat exchanger 10 where it is heated when providing cooling of the incoming feed gas as described above. Typically, the flow of this liquid from the deethanizer is via a thermosiphon cycle, but a pump can be used. The liquid stream is heated to a temperature of -4 ° F [-20 ° C] before returning to the deethanizer 15 in the middle region of the stripping section 15b as a mid-column feed, and the stream 43a is partially evaporated .

In the stripping section (15b) of the de-ethane absorber 15, the feed streams are stripped to its methane and C ₂ components. The resulting liquid product stream 37 exits the bottom of the tower at 201 ° F [94 ° C] based on the typical specification of the ethane to propane ratio of 0.048: 1 on a molar basis in the bottom product. The cooled residual gas (stream 44) passes countercurrently to the incoming feed gas from heat exchanger 10 and is heated to 98 ° F [37 ° C] (stream 44a). The residual gas is then recompressed in two stages. The first stage is a compressor (14) driven by an expansion device (13). The second stage is a compressor 20 driven by a supplemental power source that compresses the residual gas (stream 44c) to the sales line pressure. After cooling down to 120 ° F [49 ° C] in exhaust cooler 21, the residual gas stream 44d is pressurized to 915 psia [6,307 kPa (a)] sufficient to meet line requirements (typically the magnitude of the inlet pressure) To the sales gas piping.

A summary of stream flows and energy consumption for the process illustrated in Figure 1 is shown in the following table:

(Fig. 1) Stream Flow Summary - Lb. Moles / Hr [kg moles / Hr] Stream methane ethane Propane Butane + sum 31 19,419 1,355 565 387 21,961 34 18,742 1,149 360 98 20,573 35 677 206 205 289 1,388 36 18,400 1,242 3 0 19,869 38 2,759 1,758 15 0 4,602 39 1,019 86 0 0 1,116 40 1,740 1,672 15 0 3,486 41 1,044 1,003 9 0 2,092 42 696 669 6 0 1,394 43 1,388 911 365 98 2,796 44 19,419 1,328 3 0 20,985 37 0 27 562 387 976

Recovery rates ^*

Propane 99.56%

Butane + 100.00%

horsepower

Residual gas compression 9,868HP [16,223kW]

Reflux pump 19HP [31kW]

              -------- ----------

Total 9,887HP [16,254kW]

* (Based on unrounded flow)

DESCRIPTION OF THE INVENTION

Figure 2 illustrates a flow diagram of a process according to the present invention. The feed gas composition and conditions considered in the process shown in FIG. 2 are the same as in FIG. Thus, Figure 2 can be compared to that of Figure 1 to illustrate the advantages of the present invention.

In the simulation of the process of Figure 2, the incoming gas enters the plant as stream 31 and enters the heat exchange means of the feed cooling section 115a in the processing assembly 115. The heat exchange means may comprise other types of heat exchange devices including fin tube heat exchangers, plate heat exchangers, brazed aluminum heat exchangers, or multi-pass and / or multi-service heat exchangers. have. The heat exchange means is located between the stream 31 flowing through a single pass of the heat exchange means and the residual gas stream from the condensation section 115b in the processing assembly 115 and the flash expanded separator liquid (stream 35a) Lt; / RTI > Stream 31 is cooled while heating the flash expanded separator liquids and the residual gas stream. The first portion of stream 31 (stream 32) is recovered from the heat exchange means after being partially cooled to 25 ° F [-4 ° C] and the remaining second portion (stream 33) Lt; RTI ID = 0.0 > 29 C < / RTI >

The separator section 115e has an inner head or other means to divide it from the deethan absorbing section 115d so that the two sections in the processing assembly 115 can operate at different pressures. The first portion of the stream 31 (stream 32) enters the bottom of the separator section 115e at 875 psia [6,031 kPa (a)] where all the condensed liquid is vaporized by the steam passing through the separator section 115e, It is separated from the steam before it is sent to the means. The heat and mass transfer means may include other types of heat exchange devices including a finned tube heat exchanger, a flat heat exchanger, a parallel flow aluminum heat exchanger, or multi-pass and / or multi-service heat exchangers. The heat and mass transfer means is received in the treatment assembly 115 from the vapor section of the stream 32 flowing through a single path of heat and mass transfer means and the absorption section 115c inside the treatment assembly 115, ) To provide heat exchange between the distillation liquid stream (43) flowing downward from the first liquid collection means containing the first distillation liquid stream (43), so that the vapor is cooled while heating the distillation liquid stream . As the vapor stream is cooled, a portion of it can condense and fall down as the remaining vapor flows over the heat and mass transfer means. The heat and mass transfer means also serve to provide continuous contact between the condensed liquid and the vapor to provide mass transfer between the vapor and liquid phases to provide partial rectification of the vapor.

The second portion of the stream 31 (stream 33) enters the separator section 115e in the processing assembly 115 on heat and mass transfer means. All condensed liquid is separated from the vapor and mixed with all the condensed liquid from the vapor portion of the stream 32 flowing upwards through the heat and mass transfer means. The vapor portion of stream 33 is combined with the vapor leaving the heat and mass transfer means to form stream 34 which exits separator section 115e at -31 F [-35 C]. All liquids condensed from the liquid portions (if any) of the streams 32 and 33 and the vapor portion of the stream 32 of heat and mass transfer means are mixed to form a stream 35 which is cooled to -15 F [ Lt; RTI ID = 0.0 > ° C]. ≪ / RTI > Which is expanded by the expansion valve 12 to a pressure slightly higher than the working pressure (about 383 psia [2,639 kPa (a)) of the deethanizer absorption section 115d in the processing assembly 115 and the stream 35a is expanded to -42 F [-41 [deg.] C). Stream 35a enters the heat exchange means of feed cooling section 115a to supply cooling to the feed gas as described above and enters deethanizer section 115d in process assembly 115 at the lower mid- Stream 35b is heated to 103 F [39 C] before being fed.

Steam (stream 34) from separator section 115e enters work expansion device 13 where mechanical energy is extracted from this portion of the high pressure feed. The device 13 expands the vapor in a substantially isentropic manner at an operating pressure (about 380 psia [2,618 kPa (a)] of the absorbing section 115c and the work expansion expands the expanded stream 34a to about -98 ° F [-72 [deg.] C). The partially condensed expanded stream 34a is then supplied as a feed to the bottom of the absorption section 115c in the processing assembly 115. [

Absorption section 115c includes a plurality of vertically spaced trays, one or more packed beds, or absorbing means comprised of some combination of trays and packing layers. The trays and / or filling layers of the absorbing section 115c provide the necessary contact between the upwardly rising vapors and the cooled liquid falling down. The vapor portion of the expanded stream 34a rises up through the absorption means of the absorption section 115c to contact the cooled liquid falling down to condense and absorb most of the C ₃ components and heavy components from these vapors . The liquid portion of the expanded stream 34a mixes with the liquid falling down from the absorption means of the absorption section 115c to form the distillation liquid stream 43 which is absorbed at -102 F [-74 C] 115c. The distillation liquid is heated to -9 ° F [-23 ° C] as it cools the vapor portion of stream 32 in separator section 115e as described above, and the heated distillation liquid stream 43a is then fed to the upper mid- Is fed to the deethanizer section 115d in the processing assembly 115 at the column feed point. Typically, the flow of this liquid from the absorption section 115c to the deethanizer absorption section 115d through the heat of the separator section 115e and the mass transfer means is through a thermal siphon circulation, but a pump can be used.

The absorbing section 115c has an internal head or other means to divide it from the deethan absorbing section 115d so that the two sections in the processing assembly 115 are of a slightly higher ethane absorption section 115d than the absorbing section 115c It can operate with pressure. This pressure differential is collected in the first vapor collection means housed in the treatment assembly 115 and then recovered from the top of the deethanizer absorption section 115d and the first distillation vapor stream (stream 38) And provides the driving force to be sent to the heat exchange means of the condensing section 115b. The heat exchange means may similarly include other types of heat exchange devices including a finned tube heat exchanger, a flat heat exchanger, a parallel flow aluminum heat exchanger, multi-pass and / or multi-service heat exchangers. The heat exchange means is configured to provide heat exchange between the first distillation vapor stream 38 flowing through a single path of the heat exchange means and the second distillation vapor stream ascending from the absorption section 115c within the processing assembly 115. The second distillation vapor stream is heated while cooling and at least partially condensing the stream 38, which then exits the heat exchange means and is separated into its respective vapor and liquid phases. The vapor phase (if present) is combined with the heated second distillation vapor stream exiting the heat exchange means to form a residual gas stream that provides cooling in the feed cooling section 115a, as described above. The liquid phase is divided into two portions, stream (41, 42).

The first portion (stream 41) is fed to the top of the absorption section 115c in the processing assembly 115 by gravity flow as a cooled top column feed (feed). This cooled liquid causes the absorption cooling effect to occur within the absorption (rectification) section 115a, where saturation of the vapors rising upwardly through the tower by evaporation of the liquid methane and ethane contained in the stream 41, Lt; / RTI > This absorption refrigeration effect is achieved by heat exchange of the condensing section 115b to partially condense the first distillation vapor stream (stream 38) without operating the deethanizer absorbing section 115d at a pressure slightly higher than the absorption section 115c Allowing the second distillation vapor stream to provide the cooling required for the means. This absorption cooling effect also helps the reflux stream 41 condense and absorb the C ₃ components and heavy components of the distillation vapor flowing up through the absorption section 115c. The second portion of the liquid phase separated in the condensing section 115b (stream 42) is introduced into the top of the deethanizer section 115d in the processing assembly 115 by gravity flow as a cooled top column feed And the cooled liquid acts as a reflux to absorb and condense the C ₃ components and heavy components flowing from below to above so that the distillation vapor stream 38 contains a minimal amount of these components.

The deethanizer section 115d in the processing assembly 115 includes a plurality of vertically spaced trays, one or more packed beds, or mass transfer means comprised of some combination of trays and packed beds. The trays and / or packed bed of the deethanizer section 115d provide the necessary contact between the upwardly rising vapors and the cooled liquid falling downward. The deethanizer section 115d also includes heat and mass transfer means under the mass transfer means. The heat and mass transfer means may include other types of heat exchange devices including a finned tube heat exchanger, a flat heat exchanger, a parallel flow aluminum heat exchanger, or multi-pass and / or multi-service heat exchangers. The heat and mass transfer means comprises a heating medium flowing through a single path of heat and mass transfer means and a distillation liquid stream (not shown) that is received in the processing assembly 115 and falls down from the second liquid collection means connected to the mass transfer means and the heat and mass transfer means 43), so that the distillation liquid stream (second distillation liquid stream) from the mass transfer means is heated in the heat and mass transfer means. When the distillation liquid stream is heated, a portion thereof is vaporized to form stripping vapors rising upwardly as the remaining liquid continues to fall downward through the heat and mass transfer means. Heat and mass transfer means provides continuous contact between the stripping steam and the distillate liquid stream and a liquid product stream 37 of steam and to also function to provide mass transfer between the liquid phases, methane, C ₂ components and lighter components Stripping. The resulting liquid product (stream 37) leaves the bottom of the deethanizer section 115d and leaves the processing assembly 115 at 203 ° F [95 ° C].

The second distillation vapor stream rising from the absorption section 115c is collected in the second vapor collection means contained in the processing assembly 115 and then collected in the condensation section 115b as it provides cooling to the stream 38, It gets warm. The warmed second distillation vapor stream is combined with all of the vapor separated from the cooled first distillation vapor stream 38 as described above. The resultant residual gas stream is heated in the feed cooling section 115a as it provides cooling to the stream 31 as described above so that the residual gas stream 44 is heated at 104 [ (115). The residual gas stream is then recompressed in two stages, a compressor (14) driven by an expansion device (13) and a compressor (20) driven by an auxiliary power source. After cooling from the outlet cooler 21 to 120 ° F [49 ° C], the residual gas stream 44c has a pressure of 915 psia [6,307 kPa (a)] sufficient to meet line requirements (which is typically the magnitude of the inlet pressure) To the sales gas piping.

A summary of stream flows and energy consumption for the process illustrated in Figure 2 is shown in the following table:

(Figure 2) Stream Flow Summary - Lb. Moles / Hr [kg moles / Hr] Stream methane ethane Propane Butane + sum 31 19,419 1,355 565 387 21,961 32 4,855 339 141 97 5,490 33 14,564 1,016 424 290 16,471 34 18,870 1,135 348 104 20,683 35 549 220 217 283 1,278 38 2,398 1,544 13 0 4,015 41 1,018 868 8 0 1,924 42 737 628 5 0 1,394 43 1,112 723 353 104 2,320 44 19,419 1,328 3 0 20,984 37 0 27 562 387 977

Recovery rates ^*

Propane 99.63%

Butane + 100.00%

horsepower

Residual gas compression 9,363HP [15,393kW]

* (Based on unrounded flow)

A comparison of Tables 1 and 2 shows that the present invention maintains essentially the same recovery rate as the prior art. However, additional comparisons between Table 1 and Table 2 show that production yields were achieved using significantly less power than prior art. Regarding the recovery efficiency (defined as the amount of propane recovered per unit power), the present invention shows an improvement of 5% or more over the prior art of the process of FIG.

The improvement of the recovery efficiency provided by the present invention with respect to the prior art of the process of Fig. 1 is mainly due to three factors. First, a compact arrangement of the heat exchange means of the feed cooling section 115a of the processing assembly 115 and the condensation section 115b of the processing assembly 115 is provided by the interconnect piping that is found in conventional processing plants Remove pressure drop. As a result, the residual gas flowing into the compressor 14 is at a higher pressure for the present invention than in the prior art, so that the residual gas entering the compressor 20 is at a slightly higher pressure, Lt; / RTI >

Secondly, the heat and mass transfer means 115d in the deethanizer absorbing section 115d is configured to heat the distillation liquid leaving the mass transfer means of the deethanizer section 115d while simultaneously causing the resulting vapors to contact the liquid and strip the volatile components. Is more effective than using a conventional distillation column with external reboilers. The volatile components are continuously stripped from the liquid to improve the stripping effect for the present invention by reducing the concentration of volatile components in the stripping vapors more rapidly.

Third, the use of heat and mass transfer means in the separator section 115e to cool the vapor portion of the stream 32 and to condense the heavy hydrocarbon components from the vapor may subsequently expand and cause the absorption section 115c Provide partial rectification of stream 34 before being fed. The As a result, less reflux stream (stream 41) expanded to remove the Table 1 and as can be seen by comparing the flow rate of the stream 41 of Table 2, from which the C ₃ components and heavier components of the stream (34a).

In addition to increasing processing efficiency, the present invention provides two other advantages over the prior art. First, the compact arrangement of the processing assembly 115 of the present invention allows for the separation of the six individual equipment items (heat exchangers 10, 17) of the prior art into a single equipment item (processing assembly 115 of FIG. 2) The separator 11, the reflux separator 18, the reflux pump 19 and the fractionation tower 15). This reduces the capital cost and operating cost of the processing plant using the present invention for the prior art, reducing ground space requirements, eliminating interconnect piping, and eliminating the power consumed by the reflux pump. Second, eliminating interconnecting piping means that the processing plant using the present invention has connections with fewer flanges than in the prior art, reducing the number of potential leak sources in the plant. Hydrocarbons are volatile organic compounds (VOCs), some of which are classified as greenhouse gases and some of which may be precursors of atmospheric ozone formation, which is a potential for atmospheric release, .

Other Implementations

Some environments remove the feed cooling section 115a and condensation section 115b from the processing assembly 115 and remove the first heat exchange means 23 and the second heat exchange means 17 shown in Figures 14-21 , It may be preferable to use one or more heat exchange means outside the processing assembly for feed cooling and reflux condensation. This arrangement allows the processing assembly 115 to be smaller, which in some cases can shorten the manufacturing schedule and / or reduce the overall plant cost. It should be noted that in all cases the exchangers 23 and 17 represent either one of a plurality of heat exchangers or a single multi-path heat exchanger, or any combination thereof. Each of these heat exchangers may include other types of heat exchangers including a finned tube heat exchanger, a flat heat exchanger, a parallel flow aluminum heat exchanger, or multi-pass and / or multi-service heat exchangers. In some cases, it may be beneficial to combine feed cooling and reflux condensation in a single multi-service heat exchanger. In the heat exchanger 17 outside the treatment assembly, the reflux separator 18 and the pump 19, which are the separation means, typically separate the condensed liquid stream 40 from any residual vapor stream 39, And at least a portion of the stream to the absorption section 115c as reflux. Any residual vapor stream (39) is combined with the heated second distillation vapor stream in combination means to form a combined vapor stream (44).

2, the first distillation vapor stream 38 is partially condensed and the resultant condensate is passed through the C ₃ components and heavy components, which are valuable, to the work expansion device < RTI ID = 0.0 > From the leaving vapors. However, the present invention is not limited to this embodiment. For example, if the condensate should be bypassed to the absorption section 115c of the processing assembly 115, or if other design considerations point to portions of the expansion device outlet, only a portion of the condensate may be used as the absorbent, It may be beneficial to treat only a portion of the outlet vapor from the work expansion device. The supply gas conditions, plant size, usable equipment, or other factors may be used to remove the work expansion device 13, which is the expansion means, or to replace it with another expansion device (such as an expansion valve) (Not partial) total condensation of the first distillation vapor stream 38 of the condensation section 115b in the processing assembly 115 (Figs. 14-21) or the processing assembly 115 (Figs. 2-13) . Depending on the composition of the feed gas stream, an external refrigerator (not shown) may be provided to provide partial cooling of the first distillation vapor stream 38 of the heat exchanger 17 (Figs. 14-21) or the condensing section 115b May be beneficial.

In some circumstances, rather than including the separator section 115e, which is an additional separation means of the processing assembly 115, it is also possible to separate the cooled first and second portions 32, 33 or the cooled feed stream 31a It may be beneficial to use an external separator. 8 and 18, the additional heat and mass transfer means of the separator 11, which is a further separating means, directs the cooled first and second portions 32, 33 to the vapor stream 34 and the liquid stream 35 ). ≪ / RTI > Similarly, as shown in Figs. 9-13 and 19-21, the separator 11, which is an additional separation means, separates the cooled feed stream 31a into a vapor stream 34 and a liquid stream 35 .

The selection of process streams for specific heat exchange services, the specific arrangement of heat exchangers to cool the first distillation vapor stream 38 and the feed gas (streams 31 and / or 32), the absorption section 115c for process heat exchange, And the use and distribution of the liquid stream 35 from the separator section 115e or separator 11, which is the further separation means, should be evaluated for each particular application. 4, 5, 10 and 11), heat exchangers (Figs. 6 and 12), and condenser sections 115a, Or to supply a portion of the cooling of the first distillation vapor stream 38 of the heat exchanger 17 (Figures 16, 20). In these cases, the additional heat and mass transfer means may not be necessary for separator section 115e (Figures 4-6, 16) or separator 11 (Figures 10-12, Figure 20) have. In the embodiments shown in Figures 4 and 10, a pump 22 is used to deliver the distillation liquid stream 43 to the heat exchange means of the condensation section 115b. 5 and 11, the condensation section 115b is located below the absorption section 115c of the processing assembly 115 and the flow of the distillation liquid stream 43 is through a thermal siphon circulation. 6 and 12, the third heat exchange means 10 outside the processing assembly 115 is used and the feed cooling section 115a is located below the absorption section 115c of the processing assembly 115 And the flow of the distillation liquid stream 43 is through thermal siphon circulation. (Embodiments shown in FIGS. 5, 6, 11, and 12 provide reflux to locations on the point of the processing assembly 115 The condensed liquid phase is collected from the stream 38). In the embodiments shown in Figures 16 and 20, the thermal siphon circulation allows the distillation liquid stream 43 to undergo heat exchange It may be sufficient to flow through the vessel 17 or the pump 22 may be required to circulate the stream 43. Some environments may include a distillation liquid stream 43 to cool the stream 32 in a heat exchanger external to the processing assembly 115, such as the heat exchanger 10 illustrated in Figures 3, 9, 15, You may prefer to use it. Other situations do not heat the distillation liquid stream 43 at all and instead use a distillation liquid stream (not shown) as reflux on top of the deethanization section 115d as shown in Figures 7, 13, 17, 43 is received in the treatment assembly 115 and is connected to the absorption means 115c to receive the first distillation liquid stream 43 from the lower portion of the absorption means 115c, It may be preferable to provide a first liquid collection means that connects the mass transfer means 115d to the first liquid collection means to receive the first distillation liquid stream 43a as an upper feed thereto. , In the embodiment shown in Figure 21, the pump 22 may be required because the gravity flow of the stream 43 may not be possible.

Depending on the feed gas pressure and the amount of heavy hydrocarbons in the feed gas, the cooled first and second portions 32, 32 entering the separator 11 of Figures 8 and 18 or the separator section 115e of Figures 2 and 14, 33 (or the cooled feed stream 31a (see FIG. 9) entering the separator section 115e, which is the separator 11 of FIGS. 9-13 and 19-21 or the further separating means of FIGS. 3-7 and 15-17, ) May contain no liquid (because it is above its dew point, or above its maximum critical pressure (cricondenbar)). In these cases, there is no liquid in the stream 35 (as shown by the dashed lines). In this situation, the separator section 115e (Figs. 2-7 and 14-17) or the separator 11 (Figs. 8-13 and Figs. 18-21), which are additional separating means of the processing assembly 115, May not be necessary.

In accordance with the present invention, it is advantageous to use an external refrigerator to supplement the cooling available for the first distillation vapor stream and / or the incoming gas from the second distillation vapor stream and the distillation liquid streams, especially in the case of a rich inflow gas , Can be used. Additional inflow gas coolers In these cases where additional heat and mass transfer means are required, the separator section 115e (or the cooled separator), which is further separating means as shown by the dashed lines in Figures 3-7 and 15-17, 9 and 13), or the additional heat and mass transfer means may be included in the gas collection means of these cases when the first and second portions 32, 33 or the cooled feed stream 31a contain no liquid, And separator 11, which is an additional separation means as shown by the dashed lines in FIGS. 19-21. The heat and mass transfer means may include other types of heat exchange devices including a finned tube heat exchanger, a flat heat exchanger, a parallel flow aluminum heat exchanger, or multi-pass and / or multi-service heat exchangers. The heat and mass transfer means are configured to provide heat exchange between a refrigerant stream (e.g., propane) flowing through a single path of heat and mass transfer means and a vapor portion of stream 31a flowing upwardly, And the additional liquid is condensed, which falls downward to become part of the liquid removed in stream 35. [ (FIG. 2, FIG. 14) or separator 11 (FIG. 8, FIG. 18) as additional separating means, as shown by the broken lines in FIGS. 2, 8, The heat and mass transfer means may comprise a facility for providing auxiliary cooling with the refrigerant. Alternatively, the stream 31a may enter the separator section 115e (Figs. 3-7 and 15-17) or the separator 11 (Figs. 9-13 and 19-21) Or before the stream 32,33 enters the separator section 115e (Figures 2 and 14) or separator 11 (Figures 8 and 18), which are further separating means, the conventional gas chiller May be used to cool stream 32, stream 33 and / or stream 31a with refrigerant. In the cases where additional cooling of the first distillation vapor stream is desired, heat exchange means (Figs. 2-5, Figs. 7-11 and 13) of the condensation section 115b of the processing assembly 115, heat exchanger 10 (Figs. 6 and 12), or heat exchanger 17 (Figs. 14-21) may include facilities for providing subcooling with refrigerant as shown by chain lines.

Depending on the type of heat transfer devices selected for the heat exchange means of the condensing section 115b and the feed cooling section 115a (Figures 2 to 5, Figures 7 to 11 and 13), a single multi-pass and / It may be possible to combine these heat exchange means with a multi-service heat transfer device. In these cases, a multi-pass and / or multi-service heat transfer device may be used to heat the stream 31, stream 32, stream 33, first distillation vapor stream 38, Separating and collecting all of the steam and the second distillation vapor stream separated from the separated stream 38. For example,

The relative amount of condensed liquid that is separated between streams 41, 42 in Figures 2-6, 8-12, 14-16, and 18-20 is dependent on the gas pressure, feed gas composition, It is recognized that it depends on several factors including the amount of power. Optimal segregation can not generally be predicted without evaluating the specific situations for a particular application of the present invention. Some situations may occur where stream 41 does not supply anything to the top of deethanizer absorbing section 115d in stream 42 and is present at the top of absorbing section 115c in stream 41 as shown in dashed lines for stream 42 It may be preferable to supply all of the condensed liquid. In these cases, a heated distillation liquid stream 43a may be fed to the top of the deethanizer section 115d to act as reflux.

The present invention provides improved recovery of C ₃ components and heavy hydrocarbon components per plant consumption required to operate the process. Improvements in equipment consumption required to operate the process include reduced power requirements for compression or recompression, reduced power requirements for external refrigeration, reduced energy requirements for top reboiling, It can appear in the form of a combination.

While there have been described what are considered to be preferred embodiments of the invention, those skilled in the art will readily appreciate that other and further modifications may be made to the invention without departing from the spirit of the invention as defined by the following claims, Feeds, or other requirements of the system.

Claims (45)

A gas stream containing methane, C ₂ components, C ₃ components and heavy hydrocarbon components into a relatively less volatile fraction containing volatile residue gas fractions and most of the C ₃ and heavy hydrocarbon components In the method,
(1) the gas stream is cooled in the first heat exchange means;
(2) the cooled gas stream is expanded to low pressure so that the cooled gas stream is further cooled;
(3) the expanded and cooled gas stream is supplied as a bottom feed to absorption means contained in a single equipment item processing assembly;
(4) a first distillation liquid stream is collected from the bottom of the absorption means and fed as a top feed to the mass transfer means contained in the processing assembly;
(5) a first distillation vapor stream is collected from above the mass transfer means and sufficiently cooled to condense at least a portion of the first distillation vapor stream in the second heat exchange means;
(6) the at least partially condensed first distillation vapor stream is fed to the separating means and separated therefrom to form a residual vapor stream containing any remaining unconcentrated vapor after the first distillation vapor stream has cooled; and Form a condensed stream;
(7) at least a portion of the condensed stream is supplied as an upper feed to the absorption means;
(8) a second distillation vapor stream is collected from above the absorption means and heated in the second heat exchange means to supply at least a portion of the cooling of step (5);
(9) the heated second distillation vapor stream is combined with any of the remaining vapor streams to form a combined vapor stream;
(10) said combined vapor stream is heated in said first heat exchange means to supply at least a portion of the cooling of step (1), and thereafter discharging said heated combined vapor stream as said volatile residue gas fraction;
(11) a second distillation liquid stream is collected from the bottom of the mass transfer means and heated in the heat and mass transfer means contained in the processing assembly, while stripping the more volatile components from the second distillation liquid stream, Withdrawing the heated and stripped second distillation liquid stream from the processing assembly as the relatively less volatile fraction;
(12) the temperatures and amounts of the feed streams to the absorption means are effective to maintain the temperature of the upper portion of the absorption means at a predetermined temperature such that the majority of the components of the relatively less volatile fraction are recovered . The method according to claim 1,
(a) the gas stream is sufficiently cooled to partially condense the gas stream in the first heat exchange means;
(b) said partially condensed gas stream is fed to further separation means and separated therefrom to provide a vapor stream and at least one liquid stream;
(c) the vapor stream is expanded to a lower pressure such that the vapor stream is further cooled;
(d) said expanded and cooled gas stream is supplied to said absorption means as said lower feed;
(e) the at least one liquid stream is expanded to the lower pressure; Also
(f) heating the expanded at least one liquid stream in the first heat exchange means to supply at least a portion of the cooling of step (a), and thereafter supplying the heated and expanded liquid stream to the mass transfer means As a bottom feed. The method according to claim 1,
(a) the first distillation liquid stream is collected from the lower portion of the absorption means and heated in the second heat exchange means, and then the heated first distillation liquid stream is fed to the mass transfer means as the upper feed ; Also
(b) a first distillation vapor stream is collected from above the mass transfer means and is sufficiently cooled to condense at least a portion of the first distillation vapor stream in the second heat exchange means so that at least a portion of the heating of step (a) . The method of claim 3,
(i) said gas stream is sufficiently cooled to partially condense said gas stream in said first heat exchange means;
(ii) said partially condensed gas stream is fed to further separation means and separated therefrom to provide a vapor stream and at least one liquid stream;
(iii) the vapor stream is expanded to a lower pressure such that the vapor stream is further cooled;
(iv) said expanded and cooled gas stream is supplied to said absorption means as said lower feed;
(v) the at least one liquid stream is expanded to the lower pressure; Also
(vi) the expanded at least one liquid stream is heated in the first heat exchange means to supply at least a portion of the cooling of step (i), and thereafter supplying the heated and expanded at least one liquid stream to the mass transfer means As a bottom feed. The method according to claim 1,
(a) the gas stream is partially cooled in the first heat exchange means;
(b) the partially cooled gas stream is divided into first and second portions;
(c) the first portion is further cooled in further heat and mass transfer means contained in the further separating means, while condensing any less volatile components from the first portion;
(d) said second portion is further cooled in said first heat exchange means;
(e) said further cooled first portion and said further cooled second portion are combined to form said cooled gas stream;
(f) the first distillation liquid stream is collected from the lower portion of the absorption means and heated in the additional heat and mass transfer means to supply at least a portion of the cooling of step (c), and the heated first distillation liquid stream And thereafter fed to said mass transfer means as said upper feed;
(g) said combined vapor stream is heated in said first heat exchange means to supply at least a portion of the cooling of steps (a) and (d), and thereafter supplying said heated combined vapor stream to said volatile residue gas fraction / RTI > The method of claim 5,
(i) the further cooled second portion is sent to the further separating means so that the first portion is further cooled and any liquids condensed as the second portion is further cooled are combined to form one or more liquid streams And the remainder of the further cooled first portion and the further cooled second portion form a vapor stream;
(ii) the vapor stream is expanded to a lower pressure such that the vapor stream is further cooled;
(iii) said expanded and cooled vapor stream is supplied to said absorption means as said bottom feed;
(iv) the at least one liquid stream is expanded to the lower pressure;
(v) heating the expanded at least one liquid stream in the first heat exchange means to supply at least a portion of the partial cooling of step (a), and thereafter transferring the heated and expanded liquid stream Means as a bottom feed. The method according to claim 1,
(i) said gas stream is partially cooled in said first heat exchange means;
(ii) said partially cooled gas stream is divided into first and second portions;
(iii) the first portion is further cooled in the third heat exchange means;
(iv) said second portion is further cooled in said first heat exchange means;
(v) said further cooled first portion and said further cooled second portion are combined to form said cooled gas stream; Also
(vi) the first distillation liquid stream is collected from the lower portion of the absorption means and heated in the third heat exchange means to supply at least a portion of the cooling of Step (iii); Wherein the heated first distillation liquid stream is subsequently fed to the mass transfer means as the top feed. The method of claim 7,
(A) said further cooled first portion and said further cooled second portion are combined to form a partially condensed gas stream;
(B) said partially condensed gas stream is fed to said further separation means and separated therefrom to provide a vapor stream and at least one liquid stream;
(C) the vapor stream is expanded to a lower pressure such that the vapor stream is further cooled;
(D) said expanded and cooled vapor stream is supplied to said absorption means as said bottom feed;
(E) said at least one liquid stream is expanded to said lower pressure; Also
(F) heating the expanded at least one liquid stream to heat at the first heat exchange means to supply at least a portion of the partial cooling of step (A), and thereafter transferring the heated and expanded liquid stream Means as a bottom feed. The method of claim 2,
Wherein the further separating means is housed in the processing assembly. The method according to claim 4 or 8,
Wherein the further separating means is housed in the processing assembly. The method according to claim 5 or 6,
Wherein the further separating means is housed in the processing assembly. The method according to claim 3 or 7,
(1) the heated first distillation liquid stream is fed to the mass transfer means at an intermediate feed position;
(2) said condensed stream is divided into at least a first and a second reflux stream;
(3) said first reflux stream is supplied to said absorption means as said upper feed;
(4) the second reflux stream is fed to the mass transfer means as the top feed. The method according to claim 4 or 8,
(1) the heated first distillation liquid stream is fed to the mass transfer means at an intermediate feed position;
(2) said condensed stream is divided into at least a first and a second reflux stream;
(3) said first reflux stream is supplied to said absorption means as said upper feed;
(4) the second reflux stream is fed to the mass transfer means as the top feed. The method according to claim 5 or 6,
(1) the heated first distillation liquid stream is fed to the mass transfer means at an intermediate feed position;
(2) said condensed stream is divided into at least a first and a second reflux stream;
(3) said first reflux stream is supplied to said absorption means as said upper feed;
(4) the second reflux stream is fed to the mass transfer means as the top feed. The method of claim 10,
(1) the heated first distillation liquid stream is fed to the mass transfer means at an intermediate feed position;
(2) said condensed stream is divided into at least a first and a second reflux stream;
(3) said first reflux stream is supplied to said absorption means as said upper feed;
(4) the second reflux stream is fed to the mass transfer means as the top feed. The method of claim 11,
(1) the heated first distillation liquid stream is fed to the mass transfer means at an intermediate feed position;
(2) said condensed stream is divided into at least a first and a second reflux stream;
(3) said first reflux stream is supplied to said absorption means as said upper feed;
(4) the second reflux stream is fed to the mass transfer means as the top feed. The method of claim 1, 3, or 7,
(1) the gas collection means is received in the processing assembly;
(2) additional heat and mass transfer means are included in said gas collection means, said additional heat and mass transfer means comprising at least one path for external refrigeration medium;
(3) said cooled gas stream is fed to said gas collecting means and is further cooled by said external refrigeration medium, to said further heat and mass transfer means;
(4) the further cooled gas stream is expanded to a lower pressure and then supplied as the lower feed to the absorption means. The method of claim 12,
(1) the gas collection means is received in the processing assembly;
(2) additional heat and mass transfer means are included in said gas collection means, said additional heat and mass transfer means comprising at least one path for external refrigeration medium;
(3) said cooled gas stream is fed to said gas collecting means and is further cooled by said external refrigeration medium, to said further heat and mass transfer means;
(4) the further cooled gas stream is expanded to a lower pressure and then supplied as the lower feed to the absorption means. The method according to any one of claims 2, 4, 8 and 9,
(1) additional heat and mass transfer means are included in said further separation means, said additional heat and mass transfer means comprising at least one path for external refrigeration medium;
(2) the vapor stream is directed to the additional heat and mass transfer means to be cooled by the external refrigeration medium to form additional condensate;
(3) the condensate is part of the at least one liquid stream separated therein. The method of claim 10,
(1) additional heat and mass transfer means are included in said further separation means, said additional heat and mass transfer means comprising at least one path for external refrigeration medium;
(2) the vapor stream is directed to the additional heat and mass transfer means to be cooled by the external refrigeration medium to form additional condensate;
(3) the condensate is part of the at least one liquid stream separated therein. 14. The method of claim 13,
(1) additional heat and mass transfer means are included in said further separation means, said additional heat and mass transfer means comprising at least one path for external refrigeration medium;
(2) the vapor stream is directed to the additional heat and mass transfer means to be cooled by the external refrigeration medium to form additional condensate;
(3) the condensate is part of the at least one liquid stream separated therein. 16. The method of claim 15,
(1) additional heat and mass transfer means are included in said further separation means, said additional heat and mass transfer means comprising at least one path for external refrigeration medium;
(2) the vapor stream is directed to the additional heat and mass transfer means to be cooled by the external refrigeration medium to form additional condensate;
(3) the condensate is part of the at least one liquid stream separated therein. To separate the gas stream containing methane, C ₂ components, C ₃ components and heavy hydrocarbon components into volatile residual gas oil and relatively less volatile fractions containing most of the C ₃ and heavy hydrocarbon components In the apparatus,
(1) first heat exchange means for cooling the gas stream;
(2) expansion means connected to said first heat exchange means to receive said cooled gas stream and to expand said cooled gas stream to a lower pressure;
(3) absorbing means housed in a single equipment item processing assembly and connected to said expansion means to receive said expanded and cooled gas stream as a lower feed thereto;
(4) first liquid collection means housed in said processing assembly and connected to said absorption means to receive a first distillation liquid stream from below said absorption means;
(5) mass transfer means received in the processing assembly and connected to the first liquid collection means to receive the first distillation liquid stream as an upper feed thereto;
(6) first vapor collecting means housed in said processing assembly and connected to said mass transfer means to receive a first distillation vapor stream from above said mass transfer means;
(7) second heat exchange means connected to said first vapor collection means for receiving said first distillation vapor stream and cooling said first distillation vapor stream sufficiently to condense at least a portion of said first distillation vapor stream;
(8) receiving the at least partially condensed first distillation vapor stream and the at least partially condensed first distillation vapor stream, wherein the first distillation vapor stream is connected to the second heat exchange means, Separating means for separating the vapor stream into a condensed stream and a residual vapor stream comprising unconcentrated vapor;
(9) the absorption means is further connected to the separation means to receive at least a portion of the condensed stream as an upper feed thereto;
(10) second vapor collecting means housed in the processing assembly and connected to the absorbing means to receive a second distillation vapor stream from the top of the absorbing means;
(11) the second heat exchange means is further connected to the second vapor collection means to receive the second distillation vapor stream and to heat the second distillation vapor stream to provide at least a portion of the cooling of step (7) and;
(12) combining means connected to said second heat exchange means and said separating means for receiving said heated second distillation vapor stream and any said residual vapor stream and forming a combined vapor stream;
(13) the first heat exchange means is further connected to the combining means to receive the combined vapor stream and to heat the combined vapor stream to supply at least a portion of the cooling of step (1) Venting the combined combined vapor stream as the volatile residue gas fraction;
(14) second liquid collection means housed in the processing assembly and connected to the mass transfer means for receiving a second distillation liquid stream from the lower portion of the mass transfer means;
(15) a second distillation liquid stream which is received in the processing assembly and is connected to the second liquid collection means to receive the second distillation liquid stream and to heat the second distillation liquid stream and to separate more volatile components from the second distillation liquid stream Heat and mass transfer means for stripping and subsequently discharging said heated and stripped second distillation liquid stream from said processing assembly as said relatively less volatile fraction;
(16) a control means adapted to regulate the amounts and temperatures of the feed streams to the absorption means to maintain the temperature of the upper portion of the absorption means at a predetermined temperature so that the majority of the components of the relatively less volatile oil are withdrawn / RTI > 24. The method of claim 23,
(a) said first heat exchange means is adapted to cool said gas stream sufficiently to partially condense said gas stream;
(b) an additional separation means connected to said first heat exchange means to receive said partially condensed gas stream and separate said partially condensed gas stream into a vapor stream and at least one liquid stream;
(c) the expansion means is connected to the further separation means to receive the vapor stream and expand the vapor stream to a lower pressure to further cool the vapor stream;
(d) said absorbing means is connected to said expansion means to receive said expanded and cooled vapor stream as said lower feed thereto;
(e) an additional expansion means connected to said further separation means to receive said at least one liquid stream and to expand said at least one liquid stream to said lower pressure; Also
(f) the first heat exchange means is further connected to the additional expansion means to receive the expanded at least one liquid stream and heat the expanded at least one liquid stream to provide at least a portion of the cooling of step (a) And the first heat exchange means is further connected to the mass transfer means to supply the heated and expanded one or more liquid streams as a bottom feed thereto. 24. The method of claim 23,
(a) the second heat exchange means is further connected to the first liquid collection means to receive the first distillation liquid stream and to heat the first distillation liquid stream to produce at least the cooling of the first distillation vapor stream Supply some;
(b) the mass transfer means is connected to the second heat exchange means to receive the heated first distillation liquid stream as the top feed thereto; Also
(c) the second heat exchange means is further connected to the first vapor collection means to receive the first distillation vapor stream and to condense the first distillation vapor stream to condense at least a portion of the first distillation vapor stream And sufficiently cooled to supply at least a portion of the heating of step (a). 26. The method of claim 25,
(i) said first heat exchange means is adapted to cool said gas stream sufficiently to partially condense said gas stream;
(ii) further separation means connected to said first heat exchange means to receive said partially condensed gas stream and separate said partially condensed gas stream into a vapor stream and at least one liquid stream;
(iii) the expansion means is connected to the further separation means to receive the vapor stream and expand the vapor stream to a lower pressure to further cool the vapor stream;
(iv) said absorbing means is connected to said further expansion means to receive said expanded and cooled vapor stream as said lower feed thereto;
(v) additional expansion means connected to said further separation means to receive said at least one liquid stream and expand said at least one liquid stream to said lower pressure; Also
(vi) said first heat exchange means is further connected to said additional expansion means to receive said expanded one or more liquid streams and to heat said expanded one or more liquid streams to supply at least a portion of the cooling of step (i) And the first heat exchange means is further connected to the mass transfer means to supply the heated and expanded one or more liquid streams as a bottom feed thereto. 24. The method of claim 23,
(a) said first heat exchange means causing said gas stream to partially cool;
(b) dividing means connected to said first heat exchange means to receive said partially cooled gas stream and to divide said partially cooled gas stream into first and second portions;
(c) further heat and mass transfer means are received in the further separating means and connected to said dividing means to receive said first portion and to further cool said first portion, and wherein any less volatile component Condensing;
(d) said first heat exchange means is further connected to said dividing means to receive said second portion and further cool said second portion;
(e) an additional combination means is connected to said further heat and mass transfer means and said first heat exchange means to receive said further cooled first portion and said further cooled second portion and form a cooled gas stream;
(f) the expansion means is connected to the further combining means to receive the cooled gas stream and expand the cooled gas stream to a lower pressure;
(g) said additional heat and mass transfer means are further connected to said first liquid collection means to receive said first distillation liquid stream and to heat said first distillation liquid stream to produce at least a portion of the cooling of step (c) Supply;
(h) said mass transfer means being connected to said further heat and mass transfer means to receive said heated first distillation liquid stream as said top feed thereto; Also
(i) the first heat exchange means is further connected to the combination means to receive the combined vapor stream and to heat the combined vapor stream to provide at least a portion of the cooling of steps (a) and (d) And thereafter discharges said combined combined vapor stream as said volatile residue gas fraction. 28. The method of claim 27,
(i) said further separating means is further connected to said first heat exchange means to receive said further cooled second portion such that said first portion is further cooled and said second portion is further cooled Any of the combined liquids are combined to form at least one liquid stream, the remainder of the further cooled first portion and the further cooled second portion forming a vapor stream;
(ii) said expansion means is connected to said further separation means to receive said vapor stream and to expand said vapor stream to a lower pressure to further cool said vapor stream;
(iii) the absorption means is connected to the expansion means to receive the expanded and cooled vapor stream as the lower feed thereto;
(iv) an additional expansion means is connected to said further separation means to receive said at least one liquid stream and said at least one liquid stream to said lower pressure;
(v) said first heat exchange means is further connected to said further expansion means to receive said expanded one or more liquid streams and to heat said expanded one or more liquid streams to produce at least a portion of said partial cooling of step (a) Wherein the first heat exchange means is further connected to the mass transfer means to supply the heated and expanded one or more liquid streams as a bottom feed thereto. 28. The method of claim 27,
(i) third heat exchange means is connected to said dividing means to receive said first portion and further cool said first portion;
(ii) said additional combining means is connected to said third heat exchange means and said first heat exchange means to receive said further cooled first portion and said further cooled second portion and form said cooled gas stream ;
(iii) the third heat exchange means is further connected to the first liquid collection means to receive the first distillation liquid stream and to heat the first distillation liquid stream to supply at least a portion of the cooling of step (i) and; Also
(iv) the mass transfer means is connected to the third heat exchange means to receive the heated first distillation liquid stream as the top feed thereto. 29. The method of claim 29,
(A) said further combining means is adapted to receive said further cooled first portion and said further cooled second portion and form a partially condensed gas stream;
(B) said further separating means is connected to said further combining means to receive said partially condensed gas stream and separate said partially condensed gas stream into a vapor stream and at least one liquid stream;
(C) the expansion means is connected to the further separating means to receive the vapor stream and to expand the vapor stream to a lower pressure to further cool the vapor stream;
(D) said absorption means is connected to said expansion means to receive said expanded and cooled vapor stream as said lower feed thereto;
(E) further expansion means connected to said further separation means and receiving said at least one liquid stream to expand said at least one liquid stream to said lower pressure;
(F) said first heat exchange means is further connected to said additional expansion means to receive said expanded one or more liquid streams and to heat said expanded one or more liquid streams to produce at least a portion of said partial cooling of step (A) Wherein the first heat exchange means is further connected to the mass transfer means to supply the heated and expanded one or more liquid streams as a bottom feed thereto. 27. The method of claim 24,
Said further separating means being received in said processing assembly. 27. The method of claim 26,
Said further separating means being received in said processing assembly. 26. The method of claim 26 or 28,
Said further separating means being received in said processing assembly. 32. The method of claim 30,
Said further separating means being received in said processing assembly. 26. The method of claim 25,
(1) the mass transfer means is connected to the second heat exchange means to receive the heated first distillation liquid stream at an intermediate feed position;
(2) the dividing means is connected to the separating means to receive the condensed stream and to divide the condensed stream into at least first and second reflux streams;
(3) said absorbing means being connected to said dividing means to receive said first reflux stream as said upper feed thereto;
(4) the mass transfer means is connected to the dividing means to receive the second reflux stream as the upper feed thereto. 29. The method of claim 29,
(1) the mass transfer means is connected to the second heat exchange means to receive the heated first distillation liquid stream at an intermediate feed position;
(2) an additional dividing means is connected to said separating means to receive said condensed stream and to divide said condensed stream into at least first and second reflux streams;
(3) said absorbing means being connected to said further dividing means to receive said first reflux stream as said upper feed thereto;
(4) the mass transfer means is connected to the further dividing means to receive the second reflux stream as the upper feed thereto. 27. The method of claim 26,
(1) the mass transfer means is connected to the second heat exchange means to receive the heated first distillation liquid stream at an intermediate feed position;
(2) the dividing means is connected to the separating means to receive the condensed stream and to divide the condensed stream into at least first and second reflux streams;
(3) said absorbing means being connected to said dividing means to receive said first reflux stream as said upper feed thereto;
(4) the mass transfer means is connected to the dividing means to receive the second reflux stream as the upper feed thereto. 29. The method of claim 27 or 28,
(1) said mass transfer means is connected to said further heat and mass transfer means to receive said heated first distillation liquid stream at an intermediate feed position;
(2) an additional dividing means is connected to said separating means to receive said condensed stream and to divide said condensed stream into at least first and second reflux streams;
(3) said absorbing means being connected to said further dividing means to receive said first reflux stream as said upper feed thereto;
(4) the mass transfer means is connected to the further dividing means to receive the second reflux stream as the upper feed thereto. The method of claim 30 or 34,
(1) the mass transfer means is connected to the second heat exchange means to receive the heated first distillation liquid stream at an intermediate feed position;
(2) an additional dividing means is connected to said separating means to receive said condensed stream and to divide said condensed stream into at least first and second reflux streams;
(3) said absorbing means being connected to said further dividing means to receive said first reflux stream as said upper feed thereto;
(4) the mass transfer means is connected to the further dividing means to receive the second reflux stream as the upper feed thereto. 33. The method of claim 32,
(1) the mass transfer means is connected to the second heat exchange means to receive the heated first distillation liquid stream at an intermediate feed position;
(2) the dividing means is connected to the separating means to receive the condensed stream and to divide the condensed stream into at least first and second reflux streams;
(3) said absorbing means being connected to said dividing means to receive said first reflux stream as said upper feed thereto;
(4) the mass transfer means is connected to the dividing means to receive the second reflux stream as the upper feed thereto. 34. The method of claim 33,
(1) said mass transfer means is connected to said further heat and mass transfer means to receive said heated first distillation liquid stream at an intermediate feed position;
(2) an additional dividing means is connected to said separating means to receive said condensed stream and to divide said condensed stream into at least first and second reflux streams;
(3) said absorbing means being connected to said further dividing means to receive said first reflux stream as said upper feed thereto;
(4) the mass transfer means is connected to the further dividing means to receive the second reflux stream as the upper feed thereto. The method of claim 23, 25 or 35,
(1) a gas collecting means is housed in the processing assembly;
(2) additional heat and mass transfer means are included in said gas collection means, said additional heat and mass transfer means comprising at least one path for external refrigeration medium;
(3) said gas collection means is connected to said first heat exchange means to receive said cooled gas stream and to send said cooled gas stream to said additional heat and mass transfer means for further cooling by said external refrigeration medium;
(4) said expansion means is connected to said gas collecting means to receive said further cooled gas stream and to expand the further cooled gas stream to said lower pressure, said expansion means being further connected to said absorbing means Wherein the expanded and further cooled gas stream is supplied as the lower feed thereto. 28. The method of claim 29 or 36,
(1) a gas collecting means is housed in the processing assembly;
(2) additional heat and mass transfer means are included in said gas collection means, said additional heat and mass transfer means comprising at least one path for external refrigeration medium;
(3) said gas collecting means is connected to said further combining means to receive said cooled gas stream and to send said cooled gas stream to said additional heat and mass transfer means for further cooling by said external refrigeration medium;
(4) said expansion means is connected to said gas collection means to receive said further cooled gas stream and to expand said further cooled gas stream to said lower pressure, said expansion means being further connected to said absorbing means Wherein the expanded and further cooled gas stream is supplied as the lower feed thereto. The method of any one of claims 24, 26, 30, 31, 32, 34, 37, or 40,
(1) additional heat and mass transfer means are included in said further separation means, said additional heat and mass transfer means comprising at least one path for external refrigeration medium;
(2) said vapor stream is directed to said additional heat and mass transfer means to be cooled by said external refrigeration medium to form additional condensate;
(3) the condensate is part of the at least one liquid stream separated. 42. The method of claim 39,
(1) additional heat and mass transfer means are included in said further separation means, said additional heat and mass transfer means comprising at least one path for external refrigeration medium;
(2) said vapor stream is directed to said additional heat and mass transfer means to be cooled by said external refrigeration medium to form additional condensate;
(3) the condensate is part of the at least one liquid stream separated.

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