CN203639434U

CN203639434U - Coupling system of rectisol process and CO2 compressing process

Info

Publication number: CN203639434U
Application number: CN201320800589.4U
Authority: CN
Inventors: 钱宇; 刘霞; 杨思宇
Original assignee: South China University of Technology SCUT
Current assignee: South China University of Technology SCUT
Priority date: 2013-12-06
Filing date: 2013-12-06
Publication date: 2014-06-11
Anticipated expiration: 2023-12-06

Abstract

The utility model discloses a coupling system of a rectisol process and a CO2 compressing process. The coupling system is characterized in that a CO2 flash column is arranged at the bottom of a CO2 desorption column and an H2S concentrating column of the rectisol process; a CO2 multi-stage compressing device and a pump pressurizing device are provided for the CO2 compressing process; the bottom of the CO2 desorption column is connected with a first heat exchanger through a pipeline and then is connected with the CO2 flash column; the tail end of the CO2 multi-stage compressing device is connected with the first heat exchanger through the pipeline and then is connected with the pump pressurizing device. According to the coupling system of the rectisol process and the CO2 compressing process, the heat produced by the CO2 compression is recycled and used as a heat source for raising the temperature of methanol-enriched fluid which can enhance the desorption of CO2 during the rectisol process, the cooling capacity of the methanol-enriched fluid at the bottom of the CO2 desorption column is also utilized, thus the power consumption in refrigerating during compression is saved, and the energy utilization rate is also raised.

Description

A kind of low-temp methanol washing process and CO 2the coupled system of compression process

Technical field

The utility model relates to gas sweetening field and reduction of greenhouse gas discharge field, is specifically related to a kind of low-temp methanol washing process and CO ₂the coupled system of compression process.

Background technology

CO ₂total emission volumn in 100 years, increase substantially in the past, cause global temperature on average obviously to rise, Greenhouse effect have become one of the severeest environmental problem of 21 century facing mankind.The mineral fuel such as coal, oil are utilized to the CO that produces and discharge in process ₂separate and reclaim, seal up for safekeeping and utilize (CCS & CCUS) to cause the generally attention of countries in the world.

An important directions that has become clean coal utilization with the leading Modern Coal-based Chemical technology of gasification, the efficiency of utilization with coal is high, and process cost is low, dust, NO _x, SO ₂approach the feature of zero release Deng pollutent.Modern coal gasification course has that not only raw material sources are wide, and efficiency of utilization is high, can realize CO before burning simultaneously ₂remove and trap, realize CO with lower energy consumption and Financial cost ₂reduction of discharging.At following CO ₂in reduction of discharging process, CO before coal gasification and combustion ₂the combination of trapping technique will have a wide range of applications.

Low-temp methanol washing process is a kind of CO of ripe commercial applications ₂, H ₂s gas removal technology is also to have the front CO of representational burning ₂isolation technique.Utilize methyl alcohol physical property large to sour gas solubleness under cold condition, can effectively from crude synthesis gas, remove H ₂s, CO ₂deng sour gas, make synthetic gas reach very high degree of purification.

Taking coal as raw material, after gasifying process adopts the technological process of chilling process, low-temperature rectisol can effectively remove the CO in thick conversion gas simultaneously ₂and H ₂the impurity such as S.Low-temperature rectisol gas purifying technique, in being purified synthetic gas, can byproduct gas: rich H ₂s gas product and CO ₂gas product.High concentration CO ₂general 60% left and right of the rate of recovery of gas product in technique.Residue CO ₂most of in emission, concentration is roughly 60～85%, this part CO ₂because concentration is lower, obtain high concentration CO ₂energy consumption and expense high, most processing modes are for directly emptying.Also has a small amount of CO ₂at rich H ₂s gas product, enters Sulfur Recovery Unit process with gas product.

The high concentration CO that technique produces ₂gas product enters before pipe is carried needs to carry out processed compressed.CO ₂the compression section of gas product can be carried out in two steps: first with compressor by CO ₂gas compression is the liquid state with certain pressure, then utilizes the further force value to regulation by its pressure-raising of pump.The normal dividing point as pump and compressor operating interval by (60bar, 23 DEG C) in engineering, adopts compressor compresses, higher than adopting pump to compress after 60bar during lower than 60bar.After compressor compresses, CO ₂temperature can exceed 23 DEG C, in order to ensure the CO when the pump ₂in liquid state, must be to CO ₂carry out cooling process, make its temperature be no more than 23 DEG C.

For the consideration to pipe safety, reliability service and comparable economy, CO ₂the pressure of pipeline transfer designs and operation is within the scope of 8.27-17.23MPa, and temperature range is from surface temperature to the highest approximately 48.9 DEG C.Under such design and operational condition, can make highly purified CO ₂gas product keeps under stable overcritical or fine and close phase, thereby has eliminated the unstable of potential two-phase transport.Table 1 is a large amount of CO ₂gas product pipeline is carried requirement.The CO that low-temperature rectisol trapping system traps ₂can meet above requirement, without further purification.The CO of this concentration ₂can be for geological storage or enhanced oil recovery.

The typical CO of table 1 ₂pipeline is carried requirement

Application number is to disclose a kind of high CO in 201310247525.0 application for a patent for invention ₂low-temp methanol washing method and the device of yield, as shown in Figure 1.At CO ₂at the bottom of desorption tower and H ₂between S upgrading tower, increase CO ₂flashing tower, by CO ₂intensification, the step-down strengthening of the methyl alcohol rich solution at the bottom of desorption tower reach CO ₂strengthening desorb, has raising CO ₂the effect of product yield, its CO ₂gas product yield can effectively be increased to 91.2%.The CO of the high yield obtaining in technique ₂gas product, by multistage indirect cooled compressed, obtains the CO that liquefies ₂product, for Chemical Manufacture, enhanced oil recovery or geological storage.But have the following disadvantages in above-mentioned technology:

(1) improve CO ₂gas product yield, is supplied with methyl alcohol rich solution is heated up by additional heat.Along with the raising of capture rate, in technique, need to increase additional heat input and roll up.

(2) improve CO ₂gas product yield, is supplied with and is made CO by extra cold ₂the rich CO of flash distillation tower top ₂compressed gas cooling is transmitted back to CO ₂at the bottom of desorption tower.Along with the raising of capture rate, in technique, needing to increase extra cold input increases.

(3) CO ₂compression process needs certain cold input, and along with CO ₂the increase of gas product, the power consumption meeting of cooling process rolls up.

(4) CO ₂strengthening desorption process and CO ₂it is unreasonable that compression process exists energy to utilize, and has the too high problem of process energy consumption.

Utility model content

The purpose of this utility model is to solve the high CO of above-mentioned one ₂the low-temp methanol washing process of yield is improving CO ₂when yield, energy utilizes the technological problems unreasonable, process energy consumption is too high, and a kind of low-temp methanol washing process and CO are provided ₂the coupling process of compression process and system, the method and system can be at high CO ₂under the yield condition of gas product, rationally utilize cold and CO in system ₂heat in compression process, reduces high CO ₂system energy consumption under capture rate, reduces running cost.

The technical scheme that the utility model solves the problems of the technologies described above is:

A kind of low-temp methanol washing process and CO ₂the coupling process of compression process, wherein, the CO in low-temp methanol washing process ₂at the bottom of desorption tower and H ₂between S upgrading tower, be provided with CO ₂flashing tower, CO ₂compression process has CO ₂stage compression device and pump pressure-raising device, this coupling process comprises the following steps:

By described CO ₂methyl alcohol rich solution at the bottom of desorption tower tower and described CO ₂the compression CO of stage compression device end ₂gas product is coupled by an interchanger, and the methyl alcohol rich solution after coupling is sent into described CO ₂flashing tower, the compression CO after coupling ₂gas product cooling liquefaction becomes liquefaction CO ₂product is carried by pump pressure-raising device pressure-raising to pipeline transfer pressure.

A preferred version of coupling process of the present utility model, wherein, as CO in described low-temp methanol washing process ₂when yield is 60.4%～79%, this coupling process comprises the following steps:

(1) in low-temp methanol washing process, regeneration produces methyl alcohol lean solution and H ₂methyl alcohol rich solution and CO at the bottom of S upgrading tower tower ₂methyl alcohol rich solution at the bottom of desorption tower tower carries out being respectively delivered to acid gas absorption tower tower top after heat exchange cooling;

(2) CO ₂after methyl alcohol rich solution at the bottom of desorption tower tower and the heat exchange of methyl alcohol lean solution heat up, then with CO ₂the rich CO of flashing tower tower top ₂gas carries out heat exchange intensification, then with CO ₂the compression CO of stage compression device end ₂gas product, by the interchanger intensification that is coupled, is finally sent into described CO ₂flashing tower.

A preferred version of coupling process of the present utility model, wherein, as CO in described low-temp methanol washing process ₂when yield is 80%～91.2%, this coupling process comprises the following steps:

(2) CO ₂after methyl alcohol rich solution at the bottom of desorption tower tower and the heat exchange of methyl alcohol lean solution heat up, then with CO ₂the compression CO of stage compression device end ₂gas product is by the intensification that is coupled of an interchanger, then with CO ₂heat exchange intensification is carried out in recirculated water hot junction in stage compression device, finally sends into described CO ₂flashing tower.

A preferred version of coupling process of the present utility model, wherein, as CO in described low-temp methanol washing process ₂when yield is 60.4%～79%, CO ₂after methyl alcohol rich solution at the bottom of desorption tower tower and the heat exchange of methyl alcohol lean solution heat up, service temperature is-33～-31 DEG C; Again with CO ₂the rich CO of flashing tower tower top ₂gas carries out after heat exchange intensification, and service temperature is-31～-28 DEG C; Again with CO ₂the compression CO of stage compression device end ₂gas product is coupled after intensification by an interchanger, and service temperature is-26～-6 DEG C.

A preferred version of coupling process of the present utility model, wherein, as CO in described low-temp methanol washing process ₂when yield is 80%～91.2%, CO ₂after methyl alcohol rich solution at the bottom of desorption tower tower and the heat exchange of methyl alcohol lean solution heat up, service temperature is-24～0 DEG C; Again with CO ₂the compression CO of stage compression device end ₂gas product is coupled after intensification by an interchanger, and service temperature is-6～18 DEG C; Again with CO ₂carry out after heat exchange intensification in recirculated water hot junction in stage compression device, and service temperature is-6～35 DEG C.

A kind of low-temp methanol washing process and CO ₂the coupled system of compression process, wherein, the CO in low-temp methanol washing process ₂at the bottom of desorption tower and H ₂between S upgrading tower, be provided with CO ₂flashing tower, CO ₂compression process has CO ₂stage compression device and pump pressure-raising device, described CO ₂at the bottom of desorption tower tower, be connected in after First Heat Exchanger again and described CO by pipeline ₂flashing tower connects, described CO ₂stage compression device end is connected with pump pressure-raising device after being connected in described First Heat Exchanger by pipeline again.

A preferred version of coupled system of the present utility model, wherein, described CO ₂stage compression device comprises compressor and multiple interchanger with stage compression cylinder, and described every grade of compression cylinder is outside equipped with interchanger, and each interchanger is connected with water inlet pipe and rising pipe respectively.

A preferred version of coupled system of the present utility model, wherein, in described low-temp methanol washing process regeneration produce methyl alcohol lean solution transfer lime respectively with H ₂at the bottom of S upgrading tower tower, be connected on the second interchanger and CO ₂at the bottom of desorption tower tower, be connected on the 3rd interchanger;

Described CO ₂after being connected on described the 3rd interchanger by pipeline at the bottom of desorption tower tower, then with CO ₂flashing tower tower top is connected on the 4th interchanger, is then connected with described First Heat Exchanger, last and described CO ₂flashing tower connects.

Described CO ₂after being connected on described the 3rd interchanger by pipeline at the bottom of desorption tower tower, then be connected with described First Heat Exchanger, be then connected on the 5th interchanger with described rising pipe, last and described CO ₂flashing tower connects.

The utility model compared with prior art has following beneficial effect:

In low-temp methanol washing process, in order to improve CO ₂product yield, at CO ₂at the bottom of desorption tower and H ₂between S upgrading tower, increase CO ₂flashing tower, CO ₂low-temp methanol rich solution at the bottom of desorption tower need enter CO after intensification, step-down again ₂flashing tower is strengthened desorb; And at CO ₂in compression process, CO ₂gas, after repeatedly compressing, need to be cooled to certain temperature to be just convenient to follow-up pumping; The utility model utilize dexterously in above-mentioned two technological processs one need to heat up, a feature that needs are cooling, both are coupled, realize the mutual utilization of energy, make above-mentioned treating processes in two techniques without providing separately heat or cold by outside again, save power consumption, improved the capacity usage ratio of total system.

Brief description of the drawings

Fig. 1 is the high CO of one of the prior art ₂the low-temp methanol washing process schema of yield, wherein: 4 absorption towers; 14CO ₂desorption tower; 19H ₂s upgrading tower; The hot regenerator column of 28 methyl alcohol; 43 methanol rectifying towers, 50CO ₂flashing tower; 3,11,12,13,30,33 is flashing tower; 2,8,9,10,25,27,29,32,36,42,46,49,53 is interchanger; 26,31,38,41,55 is pump; 43,52 compressors; 1,5,6,7,15,16,17,18,20,22,23,34,35,37,39,40,44,45,47,48,51,54 is stock number.

Fig. 2 is low-temp methanol washing process of the present utility model and CO ₂in the coupling method, system of compression process, work as CO ₂system schematic when yield is 60.4%～78%; Wherein: 56,60,62,63,64,65 is interchanger, 61 is multi-stage compressor, and 68 is pump, 70 recirculated water cold junctions, and 71 is recirculated water hot junction, 66 is compression CO ₂gas product, 67,69 is liquefaction CO ₂product; Remaining parts numbering represents identical parts or material with the identical parts numbering in Fig. 1; And in interchanger, 60 is First Heat Exchanger, 27 is the second interchanger, and 56 is the 3rd interchanger, and 53 is the 4th interchanger.

Fig. 3 is low-temp methanol washing process of the present utility model and CO ₂in the coupling method, system of compression process, work as CO ₂system schematic when yield is 79%～91.2%; Wherein: 56,60,62,63,64,65,72 is interchanger, 61 is multi-stage compressor, and 68 is pump, 70 recirculated water cold junctions, and 71,73 is recirculated water hot junction, 66 compression CO ₂for gas product, 67,69 is liquefaction CO ₂product; Remaining parts numbering represents identical parts or material with the identical parts numbering in Fig. 1; And in interchanger, 60 is First Heat Exchanger, 27 is the second interchanger, and 56 is the 3rd interchanger, and 53 is the 4th interchanger, and 72 is the 5th interchanger.

Embodiment

Below in conjunction with embodiment and accompanying drawing, the utility model is described in further detail, but embodiment of the present utility model is not limited to this.

Referring to Fig. 1～Fig. 3, low-temp methanol washing process and CO ₂in the coupling process and system of compression process, the high CO of disclosed one in the application for a patent for invention that the basic comprising of the low temperature washing device for methanol in described low-temp methanol washing process (referring to Fig. 2 and Fig. 3) and application number are 201310247525.0 ₂the low temperature washing device for methanol (referring to Fig. 1) of yield is identical, specifically by absorption tower 4, CO ₂desorption tower 14, H ₂the compositions such as S upgrading tower 19, the hot regenerator column 28 of methyl alcohol, methanol rectifying tower 43, multiple flashing tower, multiple interchanger, multiple pump and multiple compressors, CO ₂14 ends of desorption tower and H ₂between S upgrading tower 19, be provided with CO ₂flashing tower 50, and Fig. 2, Fig. 3 represent identical parts or material with piece mark identical in Fig. 1, therefore for identical part, application number is that in 201310247525.0 application for a patent for invention, the technical process to Fig. 1 and the description of device are applicable to the description of the present embodiment to Fig. 2, Fig. 3, no longer repeats herein.

Shown in low temperature washing device for methanol of the present utility model and Fig. 1, the difference of low temperature washing device for methanol is, in the utility model, and described CO ₂methyl alcohol rich solution 16 at the bottom of desorption tower 14 towers is not to heat by outside thermal source, but and CO ₂thermal source in compression process is coupled, thereby obtains heat.

CO of the present utility model ₂compression process has CO ₂stage compression device and pump pressure-raising device, be CO with the difference of prior art ₂the compression CO of stage compression device end ₂gas product is not by the liquefaction of lowering the temperature of outside low-temperature receiver, but is coupled with the low-temperature receiver in low-temp methanol washing process, thereby obtains low-temp methanol washing process described in the utility model and CO ₂the coupling process of compression process and system.

Particularly, low-temp methanol washing process of the present utility model and CO ₂the coupling process of compression process comprises the following steps: by described CO ₂methyl alcohol rich solution 16 at the bottom of desorption tower 14 towers and described CO ₂the compression CO of stage compression device end ₂gas product is coupled by an interchanger, and the methyl alcohol rich solution 16 after coupling is sent into described CO ₂flashing tower 50, the compression CO after coupling ₂gas product cooling liquefaction becomes liquefaction CO ₂product is carried by pump pressure-raising device pressure-raising to pipeline transfer pressure again.

Low-temp methanol washing process of the present utility model and CO ₂the coupled system of compression process is: CO ₂at the bottom of desorption tower 14 towers, be connected in after First Heat Exchanger 60 again and described CO by pipeline ₂flashing tower 50 connects, described CO ₂stage compression device end is connected with pump pressure-raising device after being connected in described First Heat Exchanger 60 by pipeline again.

Further, owing to working as CO in low-temp methanol washing process ₂yield when different, state CO ₂methyl alcohol rich solution 16 at the bottom of desorption tower 14 towers is entering CO ₂temperature requirement difference before flashing tower 50, CO ₂yield higher, need temperature also higher.Meanwhile, based on the principle of low temperature cold cascade utilization, by described CO ₂at the bottom of desorption tower, 14 methyl alcohol rich solution 16 colds carry out step heat exchange, successively with recycle methanol lean solution 37, CO ₂the rich CO of compression of flashing tower 50 tower tops ₂the CO of gas 51, stage compression process ₂gas product heat exchange, thereby the technical scheme of acquisition Fig. 2.But along with CO ₂the raising of yield, CO ₂the working pressure of flashing tower 50 reduces, and compressor 52 power consumptions increase, rich CO ₂after gas 51 compressions, temperature obviously improves, at CO ₂when yield is 79-80%, rich CO ₂after gas 51 compressions, temperature is between 42-60 DEG C, at CO ₂yield during higher than 80% scope, compresses rich CO ₂gas 51 needs to cool through recirculated cooling water, and is not suitable for directly utilizing CO ₂14 methyl alcohol rich solution 16 colds at the bottom of desorption tower; And, along with CO ₂the raising of yield, CO ₂the service temperature of flashing tower 50 is corresponding improve also, enters CO ₂the methyl alcohol rich solution temperature of flashing tower heats up obviously, the therefore CO after stage compression ₂the shortage of heat of gas product is to reach operational requirement, and CO ₂the recirculated water hot junction producing in stage compression device can supplement more heat, in conjunction with this feature, forms the technical scheme shown in Fig. 3.

Embodiment when embodiment 1 and embodiment 2 are 60.4%～79% for yield below, embodiment when embodiment 3 and embodiment 4 are 80%～91.2% for yield.

Embodiment 1

Referring to Fig. 2, the low-temp methanol washing process of the present embodiment and CO ₂the coupling process of compression process comprises the following steps:

(1) in low-temp methanol washing process, regeneration produces methyl alcohol lean solution 37 and H ₂methyl alcohol rich solution 22 and CO at the bottom of S upgrading tower 19 towers ₂methyl alcohol rich solution 16 at the bottom of desorption tower 14 towers carries out being respectively delivered to acid gas absorption tower 4 tower tops after heat exchange cooling;

(2) CO ₂after methyl alcohol rich solution at the bottom of desorption tower 14 towers 16 heats up with 37 heat exchanges of methyl alcohol lean solution, then with CO ₂the rich CO of flashing tower 50 tower tops ₂gas 51 carries out heat exchange intensification, then with CO ₂the compression CO of stage compression device end ₂gas product 66, by the intensification that is coupled of an interchanger, is finally sent into described CO ₂flashing tower 50.

The low-temp methanol washing process of the present embodiment and CO ₂the coupled system of compression process is: in described low-temp methanol washing process regeneration produce methyl alcohol lean solution 37 transfer lime respectively with H ₂at the bottom of S upgrading tower 19 towers, be connected on the second interchanger 27 and CO ₂at the bottom of desorption tower 14 towers, be connected on the 3rd interchanger 56; Described CO ₂after desorption tower 14 is connected on described the 3rd interchanger 56 by pipeline, then with CO ₂flashing tower 50 tower tops are connected on the 4th interchanger 53, are then connected with described First Heat Exchanger 60, last and described CO ₂flashing tower 50 connects.

Described CO ₂stage compression device comprises compressor 61 and

multiple interchanger

62,63,64,65 with four compression cylinders, on described each compression cylinder, be provided with an interchanger, each interchanger is connected with water inlet pipe and rising pipe respectively, described water inlet pipe forms circulating water cold junction 70, and rising pipe forms recirculated water hot junction 71.Described pump pressure-raising device comprises pump 67 and transport pipe.

Coupling process below in conjunction with concrete example to the present embodiment and the working process of coupled system are described in further detail:

Referring to Fig. 2, the crude synthesis gas 1 that enters the utility model technique is from taking coal as raw material, the sulfur-resisting transformation synthetic gas that texaco gasification obtains, and the gas flow coming from conversion section is 95760Nm ³/ hr, table composed as follows.

The composition of the thick gasification gas of table 2

Gas	H ₂	N ₂	CO	AR	CH ₄	CO ₂	H ₂S	H ₂O
									Molar fraction %	45.6	0.3	19.2	0.1	0.1	34.3	0.2	0.2

Enter the unstripped gas 1 of flow process enter flashing tower 3 after interchanger 2 is cooling, at the bottom of tower, isolate water methanol solution 48.The dehydration synthetic gas going out from flashing tower 3 tower tops enters 4 bottoms, absorption tower, and low-temp methanol liquid 47, flow 168.2t/hr, service temperature-50 DEG C, working pressure 35bar are injected in 4 tops, absorption tower.On absorption tower, 4 tower tops are purified synthetic gas 5.Not containing H ₂the methyl alcohol rich solution 7 of S and rich H ₂s methyl alcohol rich solution 6 after cooling decompression, enters flashing tower 11 and flashing tower 13 respectively, carries out flash separation.

Methyl alcohol rich solution at the bottom of flashing tower 11,13 towers enters CO ₂desorption process.CO ₂at the bottom of desorption tower 14 towers, methyl alcohol rich solution 16 enters CO ₂before flashing tower 50, successively pass through

interchanger

56,53,60, the low temperature cold producing fully to recycle desorption process, wherein, after interchanger 56, service temperature is-34 DEG C, after interchanger 53, service temperature is-31 DEG C, and after interchanger 60, service temperature is-26 DEG C; CO ₂the working pressure of flashing tower 50 is 2.5bar.CO ₂the rich CO that flashing tower 50 ejects ₂gas 51 is delivered to CO after pressurization cooling ₂at the bottom of desorption tower 14 towers, greenhouse cooling-31 DEG C after interchanger 53, compressor 52 working pressures are 4bar.It is 99.1% CO that flashing tower 13 tower tops obtain volumetric concentration ₂gas product 15, gas product flow is 20068Nm ³/ hr, CO ₂the yield of gas product 15 is 60.4%.

CO ₂gas product 15 enters multistage indirect cooled compressed process, CO after interchanger 2 ₂ gas product 15 is cooled to 40 DEG C of service temperatures indirectly through stage compression device, and pressure is 70bar.Compression CO ₂gas product 66 obtains through interchanger 60 CO that liquefies ₂product, service temperature is 21 DEG C, carries out pressure-raising to pipeline transfer pressure 150bar by pump 68.

Embodiment 2

The low-temp methanol washing process of the present embodiment and CO ₂the coupling process of compression process and system are identical with embodiment 1, and difference is: CO ₂yield difference, therefore corresponding service temperature is also different.Specific as follows:

Referring to Fig. 2, CO ₂at the bottom of desorption tower 14 towers, methyl alcohol rich solution 16 enters CO ₂before flashing tower 50, successively pass through

interchanger

56,53,60, the low temperature cold producing fully to recycle desorption process, wherein, after interchanger 56, service temperature is-33 DEG C, and after interchanger 53, service temperature is-26 DEG C, after interchanger 60, service temperature is-5 DEG C, CO ₂the working pressure of flashing tower 50 is 1.7bar.CO ₂the rich CO that flashing tower 50 ejects ₂ gas 51 is delivered to CO after pressurization cooling ₂at the bottom of desorption tower 14 towers, greenhouse cooling-30.5 DEG C after interchanger 53, compressor 52 working pressures are 4bar.It is 99.0% CO that flashing tower 13 tower tops obtain volumetric concentration ₂gas product 15, gas product flow is 25357Nm ³/ hr, CO ₂the yield of gas product 15 is 78.3%.

CO ₂gas product 15 enters multistage indirect cooled compressed process, CO after interchanger 2 ₂ gas product 15 is cooled to 40 DEG C of service temperatures indirectly through stage compression device, and pressure is 65bar.Compression CO ₂gas product 66 obtains through interchanger 60 CO that liquefies ₂product, service temperature is 15 DEG C, carries out pressure-raising to pipeline transfer pressure 150bar by pump 68.

Other embodiments beyond the present embodiment is above-mentioned are identical with embodiment 1

Embodiment 3

Referring to Fig. 3, the low-temp methanol washing process of the present embodiment and CO ₂the coupling process of compression process comprises the following steps:

(2) CO ₂after methyl alcohol rich solution at the bottom of desorption tower 14 towers 16 heats up with 37 heat exchanges of methyl alcohol lean solution, then with CO ₂the compression CO of stage compression device end ₂gas product 66 is by the intensification that is coupled of an interchanger, then with CO ₂heat exchange intensification is carried out in recirculated water hot junction 71 in stage compression device, finally sends into described CO ₂flashing tower 50.

The low-temp methanol washing process of the present embodiment and CO ₂the coupled system of compression process is: in described low-temp methanol washing process regeneration produce methyl alcohol lean solution 37 transfer lime respectively with H ₂at the bottom of S upgrading tower 19 towers, be connected on the second interchanger 27 and CO ₂at the bottom of desorption tower 14 towers, be connected on the 3rd interchanger 56; Described CO ₂after being connected on described the 3rd interchanger 56 by pipeline at the bottom of desorption tower 14 towers, then be connected with described First Heat Exchanger 60, be then connected on the 5th interchanger 72 with described rising pipe, last and described CO ₂flashing tower 50 connects.

The unstripped gas that enters the utility model technique is from taking coal as raw material, the sulfur-resisting transformation synthetic gas that texaco gasification obtains, and the gas flow coming from conversion section is 104292Nm ³/ hr, table composed as follows, Fig. 3 is shown in technical process.

The composition of the thick gasification gas of table 3

Gas	H ₂	N ₂	CO	AR	CH ₄	CO ₂	H ₂S	H ₂O
									Molar fraction %	45.9	0.2	18.9	0.1	0.1	34.2	0.13	0.3

Enter the unstripped gas 1 of flow process enter flashing tower 3 after interchanger 2 is cooling, at the bottom of tower, isolate water methanol solution 48.The dehydration synthetic gas going out from flashing tower 3 tower tops enters 4 bottoms, absorption tower, and low-temp methanol liquid 47, flow 186.8t/hr, service temperature-50 DEG C, working pressure 35bar are injected in 4 tops, absorption tower.On absorption tower, 4 tower tops are purified synthetic gas 5.Not containing H ₂the methyl alcohol rich solution 7 of S and rich H ₂s methyl alcohol rich solution 6 after cooling decompression, enters flashing tower 11 and flashing tower 13 respectively, carries out flash separation.

interchanger

56,60,72, the low temperature cold producing fully to recycle desorption process, wherein, after interchanger 56, service temperature is-25 DEG C, and after interchanger 60, service temperature is 6 DEG C, after interchanger 72, service temperature is-2 DEG C, CO ₂the working pressure of flashing tower 50 is 1.5bar.CO ₂the rich CO that flashing tower 50 ejects ₂ gas 51 is delivered to CO after pressurization cooling ₂at the bottom of desorption tower 14 towers, greenhouse cooling-31 DEG C after interchanger 53, compressor 52 working pressures are 4bar.It is 99.1% CO that flashing tower 13 tower tops obtain volumetric concentration ₂gas product 15, gas product flow is 28883.5Nm ³/ hr, CO ₂the yield of gas product 15 is 80.9%.

CO ₂gas product 15 enters multistage indirect cooled compressed process, CO after interchanger 2 ₂ gas product 15 is cooled to 40 DEG C of service temperatures indirectly through stage compression device, and pressure is 65bar.Compression CO ₂gas product 66 obtains through interchanger 60 CO that liquefies ₂product, service temperature is 17 DEG C, carries out pressure-raising to pipeline transfer pressure 150bar by pump 68.

Embodiment 4

Specifically be implemented as follows:

Referring to Fig. 3, the low-temp methanol washing process of the present embodiment and CO ₂the coupling process of compression process and system are identical with embodiment 3, and difference is: CO ₂yield difference, therefore corresponding service temperature is also different.Specific as follows:

CO ₂at the bottom of desorption tower 14 towers, methyl alcohol rich solution 16 enters CO ₂before flashing tower 50, successively pass through

interchanger

56,60,72, the low temperature cold producing fully to recycle desorption process, wherein, after interchanger 56, service temperature is-2 DEG C, and after interchanger 60, service temperature is 17 DEG C, after interchanger 72, service temperature is 35 DEG C, CO ₂the working pressure of flashing tower 50 is 1bar.CO ₂the rich CO that flashing tower 50 ejects ₂ gas 51 is delivered to CO after pressurization cooling ₂at the bottom of desorption tower 14 towers, greenhouse cooling-32 DEG C after interchanger 53, compressor 52 working pressures are 4bar.It is 99.3% CO that flashing tower 13 tower tops obtain volumetric concentration ₂gas product 15, gas product flow is 32431Nm ³/ hr, CO ₂the yield of gas product 15 is 91.2%.

CO ₂gas product 15 enters multistage indirect cooled compressed process, CO after interchanger 2 ₂ gas product 15 is cooled to 40 DEG C of service temperatures indirectly through stage compression device, and pressure is 65bar.Compression CO ₂gas product 66 obtains through interchanger 60 CO that liquefies ₂product, service temperature is 20 DEG C, carries out pressure-raising to pipeline transfer pressure 150bar by pump 68.

Other embodiments beyond the present embodiment is above-mentioned are identical with embodiment 3.

Above-described embodiment is preferably embodiment of the utility model; but embodiment of the present utility model is not restricted to the described embodiments; other any do not deviate from change, the modification done under spirit of the present utility model and principle, substitutes, combination, simplify; all should be equivalent substitute mode, within being included in protection domain of the present utility model.

Claims

1. a low-temp methanol washing process and CO ₂the coupled system of compression process, wherein, the CO in low-temp methanol washing process ₂at the bottom of desorption tower and H ₂between S upgrading tower, be provided with CO ₂flashing tower, CO ₂compression process has CO ₂stage compression device and pump pressure-raising device, is characterized in that described CO ₂at the bottom of desorption tower tower, be connected in after First Heat Exchanger again and described CO by pipeline ₂flashing tower connects, described CO ₂stage compression device end is connected with pump pressure-raising device after being connected in described First Heat Exchanger by pipeline again.

2. low-temp methanol washing process according to claim 1 and CO ₂the coupled system of compression process, is characterized in that, described CO ₂stage compression device comprises compressor and multiple interchanger with stage compression cylinder, and described every grade of compression cylinder is outside equipped with interchanger, and each interchanger is connected with water inlet pipe and rising pipe respectively.

3. low-temp methanol washing process according to claim 2 and CO ₂the coupled system of compression process, is characterized in that, in described low-temp methanol washing process regeneration produce methyl alcohol lean solution transfer lime respectively with H ₂at the bottom of S upgrading tower tower, be connected on the second interchanger and CO ₂at the bottom of desorption tower tower, be connected on the 3rd interchanger;

4. low-temp methanol washing process according to claim 2 and CO ₂the coupled system of compression process, is characterized in that, in described low-temp methanol washing process regeneration produce methyl alcohol lean solution transfer lime respectively with H ₂at the bottom of S upgrading tower tower, be connected on the second interchanger and CO ₂at the bottom of desorption tower tower, be connected on the 3rd interchanger;