CN116196724A - Pressure swing adsorption process for purifying high-concentration carbon dioxide from lime kiln gas - Google Patents

Pressure swing adsorption process for purifying high-concentration carbon dioxide from lime kiln gas Download PDF

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CN116196724A
CN116196724A CN202111438922.7A CN202111438922A CN116196724A CN 116196724 A CN116196724 A CN 116196724A CN 202111438922 A CN202111438922 A CN 202111438922A CN 116196724 A CN116196724 A CN 116196724A
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gas
adsorption
pressure
pressure swing
lime kiln
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刘明
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/02—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography
    • B01D53/04—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography with stationary adsorbents
    • B01D53/047—Pressure swing adsorption
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/02—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography
    • B01D53/04—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography with stationary adsorbents
    • B01D53/0407—Constructional details of adsorbing systems
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/02—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography
    • B01D53/04—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography with stationary adsorbents
    • B01D53/047—Pressure swing adsorption
    • B01D53/0476—Vacuum pressure swing adsorption
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B32/00—Carbon; Compounds thereof
    • C01B32/50—Carbon dioxide
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2258/00—Sources of waste gases
    • B01D2258/02—Other waste gases
    • B01D2258/0283—Flue gases
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02C—CAPTURE, STORAGE, SEQUESTRATION OR DISPOSAL OF GREENHOUSE GASES [GHG]
    • Y02C20/00—Capture or disposal of greenhouse gases
    • Y02C20/40—Capture or disposal of greenhouse gases of CO2

Abstract

The invention discloses a pressure swing adsorption process for purifying high-concentration carbon dioxide from lime kiln gas, wherein a pressure swing adsorption device comprises an adsorption A, a sequential PP and a product gas CO in each cycle 2 Pressurizing P, vacuumizing V and finally filling F. The method has the advantages of low investment, simplicity, easy implementation, high purity and stable CO obtaining 2 And the product gas is characterized by changing waste into valuable, and reducing environmental pollution and greenhouse gas emission.

Description

Pressure swing adsorption process for purifying high-concentration carbon dioxide from lime kiln gas
Technical Field
The invention belongs to the technical field of industrial gas adsorption separation, and in particular relates to a pressure swing adsorption process for purifying high-concentration carbon dioxide from lime kiln gas.
Background
The pressure swing adsorption method is a method of separating a specific gas by using only the difference in adsorption and desorption capacities of the adsorbent, and is commonly used for adsorption separation and purification of industrial gases. At present, the pressure swing adsorption technology has been successfully applied to the synthesis ammonia system, such as CO removal by 0.8Mpa shift gas 2 Two-stage serial CO removal of 1.7-3.0 Mpa 2 Purification of CO 2 The gas purity reaches 98 percent and is used for urea production equipment, and the gas component with higher content of the converted gas is H 2 ：～54%，N 2 ：～17%，CO 2 : 28% of the pressure is above 0.7Mpa, and the temperature is as follows: at a temperature of about 40 ℃, CO therein 2 H with main component 2 Is easy to separate, has high pressure and relatively low temperature, is easy to adsorb and CO 2 Is easy to purify. From this, one deduces that the product is rich in CO 2 Lime kiln gas with the concentration of 30 percent adopts the prior conversion under high pressure and low temperatureThe steps of adsorption, pressure equalizing and reducing, sequential discharge, replacement, evacuation, pressure equalizing and increasing and pressurizing in the gas decarburization process technology can achieve the purification effect of more than 99 percent.
For example Tang Li, et al in "pressure swing adsorption separation of CO 2 Application of the technique (pressure swing adsorption purification of CO as disclosed in chemical fertilizer industry, volume 23, phase 6, 21-23) 2 The technical indexes of the device are as follows: pressure swing adsorption purification of CO 2 The air source which is suitable for the process is CO 2 Various industrial gases with the content of 20-60 percent, such as lime kiln gas, synthetic ammonia conversion gas and the like. Can realize the product CO 2 Purity: 99.5 to 99.99 percent (liquid state), CO 2 Extraction rate: the purification effect is more than or equal to 75 percent. However, this document only uses the synthesis gas as a raw material to produce 10t/dCO 2 For example, for CO in lime kiln gas 2 The purification of (c) does not give a corresponding success.
As known, the main gas component of lime kiln gas is CO 2 ：28～35%、O 2 ：3.2～3.5%、CH 4 ：0.4～0.6%、N 2 : 57-63%, CO:3.4 to 4.5 percent of the pressure is normal pressure, and the CO 2 With main gas N 2 Is separated from H 2 Compared with the prior art, if the lime kiln gas is pressurized to 700Kpa or more, CO can be added or not 2 Purification to 95% is theoretically possible but practically difficult to determine, and the cost of pressurization electricity consumption may be greater than that of the product gas CO 2 Is of low value and economic benefit, so that enterprises try. In addition, if the lime kiln gas (or flue gas) is pressurized to 30-100 Kpa by a blower, the temperature of the raw material gas will reach about 70 ℃, but the low pressure and high temperature at 100Kpa are not suitable choices of the pressure swing adsorption device, and the lime kiln gas contains a large amount of dust and a large amount of sulfur, and the existing adsorbent can be prepared from the main gas component of the lime kiln gas as CO at low pressure and high temperature 2 ：28～35%、O 2 ：3.2～3.5%、CH 4 ：0.4～0.6%、N 2 : 57-63%, CO:3.4 to 4.5 percent of separation and purification CO 2 Up to 95% or more, it is technically difficult to determine.
In view of the fact that no successful pressure swing adsorption device is operated at present in China, the invention provides a novel pressure swing adsorption process for purifying high-concentration carbon dioxide from lime kiln gas.
Disclosure of Invention
The invention aims at solving the unreasonable operation existing in the prior art of purifying carbon dioxide in lime kiln gas by using a pressure swing adsorption technology, and provides a pressure swing adsorption process for purifying high-concentration carbon dioxide from lime kiln gas, which is a process of realizing the adsorption, sequential discharge, pressurization, vacuumizing, final pressurization and cyclic adsorption of lime kiln gas by using a pressure swing adsorption device, and can realize the extraction of CO from lime kiln gas 2 The concentration reaches more than 95% and up to 100% of the product gas, the electricity consumption is low, the industrial production value is achieved, and the method is successfully implemented on the pressure swing adsorption industrial device in China.
The invention is realized by the following technical scheme: a pressure swing adsorption process for purifying high-concentration carbon dioxide from lime kiln gas, wherein a pressure swing adsorption device comprises adsorption A, sequential PP and product gas CO in each cycle 2 Pressurizing P, vacuumizing V and finally filling F.
The raw material gas of the pressure swing adsorption device is pressurized to the pressure of 30-200 KPa by a blower, and enters an adsorption tower of the pressure swing adsorption device filled with adsorbent from the bottom, and a large amount of gas O in the lime kiln gas 2 、CH 4 、N 2 CO and partial CO 2 The gas flows out from the top of the adsorption tower by the adsorption step, and the outlet purified gas CO is controlled by increasing or decreasing the adsorption time 2 Concentration, purified gas CO 2 The concentration will influence the product gas CO 2 Concentration and yield of (a). Purifying gas CO 2 The higher the concentration, the product gas CO 2 The higher the concentration and the lower the reverse.
After the adsorption step is finished, the pressure swing adsorption device adopts a forward PP process step, and aims to put the gas in the adsorption tower into the atmosphere along the adsorption direction or into a forward tank so as to partially discharge CO 2 Gas and impurity gas O 2 、CH 4 、N 2 CO and the like are discharged from the top of the adsorption tower as much as possible, and CO is discharged 2 Is left in the adsorption tower as much as possible and put in orderThe discharged gas can be directly discharged or put into a forward discharge tank for storage for standby.
After the adsorption and forward-discharge process steps are finished, the pressure is suppressed to 10-150 KPa by a vacuum pump, and the purity of CO reaches more than 95 percent 2 The product gas enters from the bottom of the adsorption tower, the adsorption tower is pressurized from bottom to top, and the pressurized gas enters from the bottom of the adsorption tower and flows out from the top of the adsorption tower, and can be based on the product gas CO 2 The pressure and the gas quantity of the pressurizing gas can be manually or automatically adjusted, and the gas discharged by the pressurizing can be directly discharged or put into a pressurizing tank for standby. Pressurized product gas CO 2 Will directly affect the product gas CO 2 The purity and recovery rate of (C) are determined according to the actual requirement 2 Optimal balance point of purity and recovery rate, and determination of product pressurization gas CO 2 Pressure and quantity of (a) is provided. Pressurized product gas CO 2 The greater the amount, the product gas CO 2 The higher the concentration, the lower the recovery.
After the adsorption, sequential discharge and pressurization steps of the pressure swing adsorption device are finished, the vacuum pump is utilized to evacuate the adsorption tower from the bottom to V, so that high-purity CO is obtained 2 The product gas is stored in the product gas buffer tank, and the gas pressure of the product gas buffer tank is suppressed to a pressure of 10-150 KPa through an automatic regulating valve. The vacuum pump may be a reciprocating vacuum pump without water or a water ring vacuum pump with water.
After the adsorption, sequential discharge, pressurization and evacuation are finished, the pressure of the adsorption tower is increased to the adsorption pressure by adopting a final-charging F method, so that preparation is made for the next cyclic adsorption step, and the final charging can be sequential discharge gas stored in a sequential discharge tank or standby charging gas or purifying gas stored in a pressurizing tank, or one, two and three gases between the sequential discharge tank and the pressurizing tank, and the two gases and the three gases are respectively and time-division charged into the adsorption tower, so that the aim of increasing the pressure to the adsorption pressure by final charging is fulfilled. The purpose of the pressure boost by the CO-bleed gas or the pressurizing gas is to increase the CO of the product gas 2 Or recovery rate of (c) is provided.
The adsorbents of the pressure swing adsorption device are composed of one or two or more of activated alumina, activated carbon, fine pore silica gel and molecular sieve, the types and the quantity of the adsorbents are respectively layered and loaded into the adsorption tower according to actual needs, and each adsorbent is separated by a stainless steel wire mesh, so that the mixing of different adsorbents is avoided.
The number of the adsorption towers can be 2-30, and the specific number of the adsorption towers is determined according to the treatment capacity of lime kiln gas and CO of product gas 2 And (5) determining the concentration and the recovery rate.
The pressure of the raw material gas lime kiln gas can be pressurized to 30-200 KPa, and the pressure can be achieved by adopting a blower, a compressor or other equipment.
CO in purifying gas of pressure swing adsorption device 2 The concentration is only in the product gas CO 2 After the concentration reaches the requirement, the CO in the purified gas 2 The concentration control range may be any value between 1 and 33%.
Product gas CO 2 The charging pressure of (2) may be any value from 10 to 150 KPa.
Compared with the prior art, the invention has the following advantages:
(1) In the adsorption stage, the lime kiln gas after pressurization and temperature rise enters from the bottom of the pressure swing adsorption device and adsorbs a large amount of H through the adsorbent 2 O、H 2 S、CO 2 After that, part of CO 2 O and O 2 、CH 4 、N 2 The gas which is not easy to be adsorbed, such as CO, flows out from the top of the adsorption tower, and CO in the purified gas can be realized by adjusting the adsorption time 2 When controlling the concentration of CO in the purified gas 2 When the concentration of (2) is 1-33%, the CO in the product gas in the subsequent step can be improved 2 Concentration and yield of (a). In the actual operation process, the export purified gas CO of the successful case 2 The concentration can be controlled between 17 and 21 percent.
(2) The invention adopts the blower or the compressor to pressurize the lime kiln gas to 30-200 Kpa, at this time, the temperature of the lime kiln gas after being pressurized by the blower can reach 45-85 ℃, which is far lower than the electricity consumption cost required by the prior pressure swing adsorption technology when the lime kiln gas is pressurized to 0.7Mpa and then adsorbed, and simultaneously, the adsorption temperature of the pressure swing adsorption device is also satisfied.
(3) In the stamping stage, the invention uses the pressure of 10-150 Kpa and CO 2 The product gas with the concentration of more than or equal to 95 percent enters the pressure swing adsorption device from the bottom, and CO can be realized by reasonably controlling the pressure and the quantity of the product gas 2 Determination of optimal balance point of purity and recovery rate, thereby effectively improving CO in product gas 2 Concentration and recovery rate of (2) to finally realize CO 2 And extracting the product gas with the concentration of more than 95% and up to 100%.
(4) The pressure swing adsorption process can be also suitable for flue gas, can also realize extraction of more than 95% and up to 100% of product gas, and has the advantage of low power consumption.
In summary, the invention can successfully purify the product gas and make the CO thereof by reasonably pressurizing lime kiln gas (or flue gas) and utilizing the pressure swing adsorption technology 2 The purity reaches 95-100%, and the method has the advantages of simple process, convenient operation, less investment, low power consumption, quick effect and the like, has industrial production value, and has been successfully implemented on domestic pressure swing adsorption industrial devices.
Drawings
FIG. 1 is a flow chart of the process described in example 1.
FIG. 2 is a flow chart of the process described in example 2.
Detailed Description
The objects, technical solutions and advantageous effects of the present invention will be described in further detail below.
It is noted that the following detailed description is exemplary and is intended to provide further explanation of the invention as claimed, and unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In the scheme of the invention, the product gas and CO 2 The product gas is the same, and the pressurizing gas, the product pressurizing gas and the pressurizing product gas are the same.
Pressure swing adsorption technology can be used from a variety of CO-rich technologies 2 CO purification in industrial gases of (a) 2 For example, adsorption, pressure equalization, sequential discharge, displacement, evacuation, pressure equalization and pressurization steps are used to extract high purity CO from the synthesis ammonia feed gas 2 The purification concentration can reach more than 99 percent. But due to the differencesThe components of the gases contained in the industrial gases are different, and for lime kiln gases, CO is needed to be realized 2 With main gas component N 2 Is compared with the separation of CO in the feed gas of synthetic ammonia 2 And H is 2 Is more difficult, and therefore, conventional pressure swing adsorption operations do not achieve high purity CO in lime kiln gas 2 Is an extraction of (2). Further, in the prior art, when the lime kiln gas is treated by conventional pressure swing adsorption operation, the raw material gas is pressurized to 0.7Mpa and then treated, and this step has a defect of high power consumption. Therefore, the invention provides a method for enriching CO from normal pressure by reasonably controlling specific process parameters in the pressure swing adsorption operation process 2 CO purification in lime kiln gas 2 The concentration (purity can also be called as purity) reaches more than 95% and up to 100%.
The invention utilizes a pressure swing adsorption system to enrich CO 2 Lime kiln gas (lime kiln gas after water washing and dust removal, the percentage of gas components is CO) 2 ：28～35%、O 2 ：3.2～3.5%、CH 4 ：0.4～0.6%、N 2 : 57-63%, CO: 3.4-4.5%) of purifying CO 2 Gas, CO 2 The gas concentration reaches more than 95% and up to 100%. The pressure swing adsorption system consists of a blower, a gas-water separator, a plurality of adsorption towers (or pressure swing adsorption devices, 2 or more, even tens of adsorption towers), wherein the specific quantity is based on the treatment capacity of raw material gas and the CO of product gas 2 Recovery rate is determined), a product gas buffer tank, a sequential gas discharge tank or a gas filling tank, a vacuum pump, a program control valve, a driving system, a control system, an instrument and the like. One or more adsorbents are arranged in the adsorption tower, the adsorbents are composed of one or two or more of activated alumina, activated carbon, fine pore silica gel and molecular sieve, the types and the quantity of the adsorbents are respectively layered and loaded into the adsorption tower according to actual needs, and each adsorbent is separated by a stainless steel wire net, so that the mixing of different adsorbents is avoided.
During operation, lime kiln gas subjected to water washing, dust removal and desulfurization(e.g., dust removal and desulfurization will affect the service life of the adsorbent and the CO of the product gas) 2 The purity and impurity content) of the raw material is fed into a pressure swing adsorption system, a blower (or a compressor) in the system pressurizes lime kiln gas to 30-200 Kpa, at the moment, the temperature of the lime kiln gas can reach 45-85 ℃ after being pressurized by the blower, the specific temperature is determined according to the pressurizing pressure, the pressurized raw material gas with the raised temperature is fed into the adsorption tower from the bottom of the adsorption tower, and the adsorption tower is filled with a large amount of adsorbent of activated alumina, activated carbon and fine pore silica gel in layers to adsorb H 2 O、H 2 S、CO 2 Is not easy to adsorb gas O 2 、CH 4 、N 2 CO and partial CO 2 The gas flows out from the bottom of the adsorption tower, and when the CO of the purified gas 2 After the concentration reaches 1-33%, the adsorption of the inlet gas can be interrupted by adjusting the adsorption time, the adsorption step is finished, and the CO of the gas is purified 2 Concentration values will affect the product gas CO 2 For example, in a successful case, the purge gas CO 2 The concentration is controlled to be 17-21%. Then the product gas CO of 10-150 KPa generated by the vacuum pump pressure holding 2 Filling the adsorption tower from the bottom, stamping the adsorption tower, and directly influencing CO in the product gas by the pressure and the quantity of the product gas serving as the stamping gas 2 The purity and recovery rate of (C) are required to find CO 2 The optimal balance of purity and recovery determines the pressure and quantity of product gas (ram gas). The adsorption tower is then evacuated by a vacuum pump connected to the bottom of the adsorption tower to obtain CO 2 The concentration reaches more than 95% and up to 100% of the product gas, and the specific process steps are as follows: adsorption, sequential discharge, pressurization, vacuumizing, boosting and adsorption are performed circularly.
Further, the specific description of the process steps of the invention is as follows:
adsorption: means that the raw material gas, namely lime kiln gas, enters from the bottom of an adsorption tower filled with adsorbent (activated alumina, activated carbon and fine pore silica gel) through water washing, dust removal and desulfurization, wherein the gas component H which is easy to be adsorbed 2 O、H 2 S、CO 2 Is adsorbed by the adsorbent in large quantity, and is not easy to adsorb impurity gas O 2 、CH 4 、N 2 CO and partial CO 2 The gas flows out from the top of the adsorption tower, and CO flowing out from the top 2 After the concentration reaches 1-33%, the adsorption is finished, and the next process step is carried out. A success case that can be referred to is CO from the top purge gas stream 2 The concentration is controlled to be 17-21%.
And (3) forward-put: the forward discharge means that after the adsorption step is finished, the adsorption tower is filled with gas with the same high adsorption pressure, the high-pressure gas is continuously discharged along the adsorption direction or enters a forward discharge tank for storage, and then returns to the adsorption tower to improve the CO of the product gas 2 Is a recovery rate of (2). The forward discharge process is to further remove impurity gas and make CO 2 The gas is pushed to the upper part of the adsorption tower, and is put down to the lowest pressure (such as normal pressure or negative pressure) and the sequential putting step is finished.
Pressurizing: means that after the sequential discharge step is finished, the vacuum pump is utilized to build up pressure of product gas CO with the pressure of 10 to 150KPa 2 And (3) entering from the bottom of the adsorption tower, and continuously flushing the impurity gas out of the top of the adsorption tower from bottom to top along the adsorption direction. The purpose of the stamping is to further increase the purity product gas of the carbon dioxide, so that during the stamping stage, the CO is reasonably controlled 2 The pressure and quantity of the pressurized air. Therefore, the invention adopts the product gas as the impact gas, and controls the pressure of the impact gas to be 10-150 Kpa and CO 2 The concentration is more than or equal to 95 percent. The exhaust gas in the stamping process can be recycled and enters the adsorption tower which is just vacuumized as rising gas or enters the stamping gas tank to be stored and then is led into the adsorption tower from the bottom of the adsorption tower at proper time.
Vacuumizing: the purpose of the vacuum pumping is to obtain high-purity carbon dioxide product gas, and the adsorbent is regenerated, so that the adsorbent is prepared for the next cycle of adsorption. After the stamping step is finished, the high-purity CO adsorbed by the adsorbent in the adsorption tower is adsorbed by a vacuum pump 2 The desorbed CO is put into the product gas buffer tank and should be absorbed by the product gas buffer tank 2 If the pressure is controlled to 10-150 KPa through an automatic regulating valve, the product gas pressure is controlled to 30KPa for stamping in a successful scheme.
And (3) final filling: the final filling aims to increase the pressure of the adsorption tower to the adsorption pressure as much as possible, and ensure that the pressure fluctuation is smaller during adsorption. Specifically, after the vacuum step is finished, the compressed air, the forward-discharged air, the purified air or the combination thereof can be filled into the adsorption tower from the bottom of the adsorption tower for different time, so that the pressure of the adsorption tower is finally filled to the adsorption pressure, and then the final filling step is finished. Wait for the adsorption step in the next cycle to begin.
The following list of two exemplary successful embodiments is illustrative of the specific process effects of the invention, although the scope of the invention is not limited to the following examples.
Example 1: see process flow diagram 1
Lime kiln gas (or flue gas) after water washing dust removal and desulfurization is pressurized by a Roots blower, and the raw material pressure is 55KPa and the flow is 12000Nm 3 And/h, temperature: the gas composition is as follows:
Figure DEST_PATH_IMAGE002
the technological process of the pressure swing adsorption system in the successful case is shown in figure 1, C0101 is a blower, V0101 is a gas-water separator, T0101A-E are 5 adsorption towers, and V0102 is product gas CO 2 Buffer tank, P0101 is vacuum pump, KV is pneumatic program control valve. The air blower is provided with an over-pressure emptying automatic regulating valve loop on an air blower outlet pipeline, and the air blower is automatically emptied when the pressure of the air blower exceeds 65KPa so as to protect the operation safety of the air blower; an adsorption pressure automatic regulating valve loop is arranged on the purified gas outlet loop, and mainly ensures that the adsorption pressure is basically stabilized at about 55 Kpa; in the product gas CO 2 The outlet pipeline is provided with an automatic product gas pressure regulating valve loop which is mainly used for suppressing the product gas pressure generated by evacuating to 30Kpa so as to ensure the pressurizing gas CO 2 The automatic regulating circuit is the most important self-regulating circuit that must be configured. The adsorption tower is filled with three adsorbents of activated alumina, activated carbon and fine pore silica gel, and is filled with the three adsorbents in a separated and layered way by a stainless steel wire net.
The specific process steps of the embodiment are as follows: adsorption A, sequential PP, stamping P, evacuating V, final filling F, adsorption A, and circulating, taking tower A as an example:
adsorption A: opening upProgram control valve KV1A, KV A, flow 12000Nm 3 And (3) carrying out water washing, dust removal and desulfurization on lime kiln gas at the temperature of-65 ℃ under the pressure of 55KPa, then entering a gas-water separator and entering the lime kiln gas from the bottom of an adsorption tower filled with adsorbent, wherein a gas component H which is easy to adsorb is contained 2 O、H 2 S、CO 2 Is adsorbed by the adsorbent in large quantity, and is not easy to adsorb impurity gas O 2 、CH 4 、N 2 CO and partial CO 2 And (3) enabling the gas to flow out from the top of the adsorption tower, and after the concentration of CO2 flowing out from the top reaches a certain value of 17-21%, ending the adsorption and entering the next process step.
Forward PP: after the adsorption step is finished, closing KV1A, KV A, wherein gas with the same high adsorption pressure is also in the adsorption tower, starting the sequential discharge step by opening a program control valve KV4A, KV, continuously discharging high-pressure gas in the adsorption tower into the atmosphere along the adsorption direction, and regulating the discharge speed of the sequential discharge gas through a manual regulating valve V3 to reduce adsorption pressure fluctuation; the forward discharge process is to further remove the impurity gas O 2 、CH 4 、N 2 CO and CO enable 2 The gas is pushed to the upper part of the adsorption tower, and after the gas is placed under normal pressure, the sequential placing step is finished.
Pressurizing P: after the sequential discharging step is finished, a program control valve KV4A, KV is kept open, KV6A, KV is opened, product gas with the pressure of 30KPa is pumped from the bottom of the adsorption tower by a vacuum pump, and impurity gas is continuously pressurized out of the top of the adsorption tower from bottom to top along the adsorption direction and is discharged; the pressure and the quantity of the product gas (stamping gas) directly affect the purity and the recovery rate of the product gas, the stamping gas quantity can be regulated by a manual regulating valve V2, and the purpose of stamping is to further improve the CO in the product gas 2 Is a pure product of (a).
Vacuumizing V: after the stamping step is finished, closing the programmable valves KV4A, KV and KV6A, KV, opening the programmable valve KV5A, starting the evacuation step, evacuating and desorbing the high-purity product gas adsorbed by the adsorbent from the bottom of the adsorption tower by using a vacuum pump, putting the high-purity product gas into a product gas buffer tank, and holding the pressure to 30KPa through an automatic regulating valve. The evacuation process yields a high purity carbon dioxide product gas, while the adsorbent is regenerated and ready for the next cycle.
And F, final filling: the final charging aims to boost the pressure of the adsorption tower to the adsorption pressure as much as possible and ensure that the pressure fluctuation is smaller during adsorption. After the evacuation step is finished, closing a programmable valve KV5A, opening a programmable valve KV3A, KV, and starting a purified gas final filling step, wherein the pressure difference is larger when the purified gas is filled into an adsorption tower in a vacuum state due to higher pressure of the purified gas, and the final filling can adjust the pressure filling speed of the purified gas through a manual adjusting valve V1, so that the adsorption pressure fluctuation is reduced; after the final charging pressure is increased to the adsorption pressure, the final charging step is ended, and the adsorption step of the next cycle is waited for to start.
Table 1 is a timing chart of the switching operation of the program control valve of the present embodiment, and table 1 below shows the following.
Table 1 example 1 timing diagram
Figure DEST_PATH_IMAGE004
CO in the product gas obtained in this example 2 The concentration of (2) can reach 95-100% steadily, and ton CO 2 The electricity consumption is controlled at 110kwh.
Example 2: see process flow diagram 2
The configuration of the raw material gas and the device in the embodiment is basically the same as that of the embodiment 1, the newly added empty tanks are divided into two layers with different volumes in the middle, and the two layers are divided into a V0103 sequential venting tank and a V0104 pressurizing gas tank, and the specific process steps of the device are as follows: adsorption A, sequential PP, stamping P, evacuating V, final filling F, adsorption A, and circulating, taking tower A as an example:
adsorption A: opening a program control valve KV1A, KV A, and easily adsorbed gas component H in lime kiln gas 2 O、H 2 S、CO 2 Is adsorbed by the adsorbent in large quantity, and is not easy to adsorb impurity gas O 2 、CH 4 、N 2 CO and partial CO 2 The gas flows out from the top of the adsorption tower, and CO flowing out from the top 2 After the concentration reaches a certain value of 17-21%, the adsorption is finished, and the next process step is carried out.
Forward PP: after the adsorption step is finished, closing KV1A, KV A, wherein gas with the same high adsorption pressure is also contained in the adsorption tower, and opening KV4A, KV12 to start the sequential discharge step, and the adsorption towerThe internal high-pressure air is continuously put into the forward discharge tank along the adsorption direction, the outflow speed of the forward discharge air can be regulated by the manual regulating valve V3, and the forward discharge process is used for further removing the impurity gas O 2 、CH 4 、N 2 CO and CO enable 2 The gas is pushed to the upper part of the adsorption tower, and after the pressure is unchanged, the sequential discharge step is finished.
Stamping P: closing a KV12 program control valve after the forward discharging step is finished, keeping a KV4A program control valve open, opening KV6A, KV, KV13, enabling product gas with the pressure reaching 30KPa through a vacuum pump to enter from the bottom of an adsorption tower, continuously flushing impurity gas out of the top of the adsorption tower from bottom to top along the adsorption direction, and entering into a punching gas tank; the pressure and quantity of the product gas (stamping gas) will directly affect the purity and recovery rate of the product gas, the stamping gas quantity can be regulated by the manual regulating valve V2, and the purpose of stamping is to further improve the purity of the product gas.
Vacuumizing V: after the stamping step is finished, closing the programmable valves KV4A, KV and KV6A, KV11, opening the programmable valve KV5A, starting the evacuation step, evacuating and desorbing the high-purity product gas adsorbed by the adsorbent from the bottom of the adsorption tower by using a vacuum pump, putting the high-purity product gas into a product gas buffer tank, and holding the pressure to 30KPa through an automatic regulating valve. The evacuation process yields a high purity carbon dioxide product gas, while the adsorbent is regenerated and ready for the next cycle.
And F, final filling: the purpose of the final charge is to boost the pressure of the adsorption tower to the adsorption pressure as much as possible and to reduce the fluctuation of the adsorption pressure. After the evacuation step is finished, closing a programmable valve KV5A, firstly opening programmable valves KV7 and KV15, pressurizing an adsorption tower from the bottom by utilizing forward-discharge gas stored in a forward-discharge tank, adjusting the pressurizing speed by a manual valve V5, normally keeping the adsorption tower at negative pressure after the forward-discharge gas pressurizing is finished, closing a KV15 programmable valve, opening a KV16 programmable valve, pressurizing the adsorption tower from the bottom by utilizing pressurizing gas stored in a pressurizing tank, and closing a KV7A, KV programmable valve after the pressurizing is finished by adopting the purposes of improving the concentration and the recovery rate of product gas by adopting the forward-discharge gas and the pressurizing gas from the bottom of the adsorption tower; opening a KV3A, V10 program control valve, starting a purified gas final filling step, and because the pressure of the purified gas is higher, when the purified gas is filled into the adsorption tower from the top, the pressure difference is larger, and the final filling can adjust the pressure filling speed of the purified gas through a manual adjusting valve V1, so that the adsorption pressure fluctuation is reduced; after the final charging pressure is increased to the adsorption pressure, the final charging step is ended, and the adsorption step of the next cycle is waited for to start.
CO in the product gas obtained in this example 2 The concentration of (2) can reach 95-100% steadily, and ton CO 2 The electricity consumption is controlled at 110kwh.
The foregoing description is only a preferred embodiment of the present invention, and is not intended to limit the present invention in any way, and any simple modification, equivalent variation, etc. of the above embodiment according to the technical matter of the present invention fall within the scope of the present invention.

Claims (10)

1. A pressure swing adsorption process for purifying high-concentration carbon dioxide from lime kiln gas is characterized in that: the pressure swing adsorption device comprises adsorption A, PP and CO in each cycle 2 Pressurizing P, vacuumizing V and finally filling F.
2. The pressure swing adsorption process for purifying high concentration carbon dioxide from lime kiln gas of claim 1, wherein: the raw material gas of the pressure swing adsorption device is pressurized to the pressure of 30-200 KPa by a blower, and enters an adsorption tower of the pressure swing adsorption device filled with adsorbent from the bottom, and a large amount of gas O in the lime kiln gas 2 、CH 4 、N 2 CO and partial CO 2 The gas flows out from the top of the adsorption tower by the adsorption step, and the outlet purified gas CO is controlled by increasing or decreasing the adsorption time 2 Concentration, purified gas CO 2 The concentration will influence the product gas CO 2 Concentration and yield of purified gas CO 2 The higher the concentration, the product gas CO 2 The higher the concentration and the lower the reverse.
3. The pressure swing adsorption process for purifying high concentration carbon dioxide from lime kiln gas of claim 1, wherein: after the adsorption step is finished, the pressure swing adsorption device adopts forward PP process step, the purpose is to put the gas in the adsorption tower into the atmosphere along the adsorption direction or into a forward tank, thereby partial CO 2 Gas and impurity gas O 2 、CH 4 、N 2 CO and the like are discharged from the top of the adsorption tower as much as possible, and CO is discharged 2 The gas left in the adsorption tower as much as possible can be directly discharged or put into a forward discharge tank for storage for standby.
4. The pressure swing adsorption process for purifying high concentration carbon dioxide from lime kiln gas of claim 1, wherein: after the adsorption and forward-discharge process steps are finished, the pressure is suppressed to 10-150 KPa by a vacuum pump, and the purity of CO reaches more than 95 percent 2 The product gas enters from the bottom of the adsorption tower, the adsorption tower is pressurized from bottom to top, and the pressurized gas enters from the bottom of the adsorption tower and flows out from the top of the adsorption tower, and can be based on the product gas CO 2 The pressure and the gas quantity of the pressurizing gas can be manually or automatically adjusted, the gas discharged by pressurizing can be directly discharged or put into a pressurizing tank for reserve, and the pressurizing product gas CO is pressurized 2 Will directly affect the product gas CO 2 The purity and recovery rate of (C) are determined according to the actual requirement 2 Optimal balance point of purity and recovery rate, and determination of product pressurization gas CO 2 Pressure and quantity of pressurized product gas CO 2 The greater the amount, the product gas CO 2 The higher the concentration, the lower the recovery.
5. The pressure swing adsorption process for purifying high concentration carbon dioxide from lime kiln gas of claim 1, wherein: after the adsorption, sequential discharge and pressurization steps of the pressure swing adsorption device are finished, the vacuum pump is utilized to evacuate the adsorption tower from the bottom to V, so that high-purity CO is obtained 2 The product gas is stored in the product gas buffer tank, the gas pressure of the product gas buffer tank is suppressed to 10-150 KPa through an automatic regulating valve, and the vacuum pump can be an anhydrous reciprocating vacuum pump or a water ring vacuum pump with water.
6. A according to claim 1A pressure swing adsorption process for purifying high-concentration carbon dioxide from lime kiln gas is characterized in that: after the adsorption, sequential discharge, pressurization and evacuation are finished, the pressure of the adsorption tower is increased to the adsorption pressure by adopting a final-charging F method, so that preparation is made for the next cyclic adsorption step, and the final charging can be sequential discharge gas stored in a sequential discharge tank or standby charging gas or purifying gas stored in a pressurizing tank, or one, two and three gases between the sequential discharge tank and the pressurizing gas can be respectively and time-division charged into the adsorption tower, so as to achieve the aim of final charging and pressure increasing to the adsorption pressure, and the sequential discharge gas or the charging gas is used for increasing the pressure, so that the CO of the product gas is increased 2 Or recovery rate of (c) is provided.
7. The pressure swing adsorption process for purifying high concentration carbon dioxide from lime kiln gas of claim 1, wherein: the adsorbents of the pressure swing adsorption device are composed of one or two or more of activated alumina, activated carbon, fine pore silica gel and molecular sieve, the types and the quantity of the adsorbents are respectively layered and loaded into the adsorption tower according to actual needs, and each adsorbent is separated by a stainless steel wire mesh, so that the mixing of different adsorbents is avoided.
8. A pressure swing adsorption process for purifying high concentration carbon dioxide from lime kiln gas as claimed in claim 2, wherein: the number of the adsorption towers can be 2-30, and the specific number of the adsorption towers is determined according to the treatment capacity of lime kiln gas and CO of product gas 2 And (5) determining the concentration and the recovery rate.
9. A pressure swing adsorption process for purifying high concentration carbon dioxide from lime kiln gas as claimed in claim 2, wherein: the pressure of the raw material gas lime kiln gas can be pressurized to 30-200 KPa, and the pressure can be achieved by adopting a blower, a compressor or other equipment.
10. A pressure swing adsorption process for purifying high concentration carbon dioxide from lime kiln gas as claimed in claim 2, wherein: CO in purifying gas of pressure swing adsorption device 2 The concentration is only in the product gas CO 2 After the concentration reaches the requirement, the CO in the purified gas 2 The concentration control range can be any value between 1 and 33%, the product gas CO 2 The charging pressure of (2) may be any value from 10 to 150 KPa.
CN202111438922.7A 2021-11-30 2021-11-30 Pressure swing adsorption process for purifying high-concentration carbon dioxide from lime kiln gas Pending CN116196724A (en)

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