CN113200518A - Method for recovering and purifying hydrogen from semi-coke tail gas - Google Patents
Method for recovering and purifying hydrogen from semi-coke tail gas Download PDFInfo
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- CN113200518A CN113200518A CN202110654230.XA CN202110654230A CN113200518A CN 113200518 A CN113200518 A CN 113200518A CN 202110654230 A CN202110654230 A CN 202110654230A CN 113200518 A CN113200518 A CN 113200518A
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- C01B3/00—Hydrogen; Gaseous mixtures containing hydrogen; Separation of hydrogen from mixtures containing it; Purification of hydrogen
- C01B3/50—Separation of hydrogen or hydrogen containing gases from gaseous mixtures, e.g. purification
- C01B3/56—Separation of hydrogen or hydrogen containing gases from gaseous mixtures, e.g. purification by contacting with solids; Regeneration of used solids
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- C01B2203/00—Integrated processes for the production of hydrogen or synthesis gas
- C01B2203/04—Integrated processes for the production of hydrogen or synthesis gas containing a purification step for the hydrogen or the synthesis gas
- C01B2203/042—Purification by adsorption on solids
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- C01B2203/00—Integrated processes for the production of hydrogen or synthesis gas
- C01B2203/04—Integrated processes for the production of hydrogen or synthesis gas containing a purification step for the hydrogen or the synthesis gas
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- C01B2203/047—Composition of the impurity the impurity being carbon monoxide
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- C01B2203/00—Integrated processes for the production of hydrogen or synthesis gas
- C01B2203/04—Integrated processes for the production of hydrogen or synthesis gas containing a purification step for the hydrogen or the synthesis gas
- C01B2203/0465—Composition of the impurity
- C01B2203/048—Composition of the impurity the impurity being an organic compound
Abstract
The invention discloses a method for recovering and purifying hydrogen from semi-coke tail gas, wherein the semi-coke tail gas enters a two-section pressure swing adsorption hydrogen purification device under lower pressure after the procedures of purification, primary compression, desulfurization and the like, the first section pressure swing adsorption device is regenerated by using a flushing method, and most of CO in the semi-coke tail gas is regenerated2、C2+Removing, while also removing part of the N2、CO、CH4Waiting for impurity gas to obtain H2And N2The purified gas as main component is compressed for the second time, boosted and fed into the second stage pressure-variable adsorption equipment under the higher pressure to obtain H2The purity of the product hydrogen is more than or equal to 99 percent. The hydrogen in the semi-coke tail gas is recovered and purified by two sections of pressure swing adsorption devices, most of impurity gas is removed by the first section of pressure swing adsorption device under the conditions of no vacuum pump and low pressure, and then the hydrogen is compressed and pressurized to enter the second section of pressure swing adsorption device.
Description
Technical Field
The invention belongs to the field of coal chemical industry, in particular to the field of cleaning and comprehensive utilization of semi-coke tail gas, and particularly relates to a method for recovering and purifying hydrogen from the semi-coke tail gas.
Background
The semi-coke tail gas is a byproduct generated in the semi-coke production process, and the quantity of the semi-coke tail gas generated in China per year exceeds 200 hundred million Nm3. The main components are shown in table 1:
TABLE 1 main composition of semi-coke tail gas
The semi-coke tail gas contains a large amount of impurities such as tar, benzene, naphthalene, phenol, dust, sulfide, ammonia, heavy metal and the like, so the semi-coke tail gas is very difficult to recycle, and semi-coke production enterprises know that the semi-coke tail gas contains a large amount of H2、CO、CH4And the semi-coke tail gas can be only used as fuel for primary combustion utilization, and the semi-coke tail gas utilization mode not only wastes a large amount of valuable chemical resources, but also causes serious pollution.
The southwest chemical research and design institute company Limited has rich industrial tail gas purification experiences of coke oven gas, calcium carbide furnace tail gas, yellow phosphorus tail gas and the like, hydrogen in the semi-coke tail gas can be recycled and purified after the semi-coke tail gas is purified, and the purified hydrogen can be used for coal tar hydrogenation on site, so that the problem of environmental pollution of the semi-coke tail gas can be solved, waste is turned into wealth, the hydrogen resource is utilized on site, and the semi-coke tail gas purification method has high economic value.
According to the specific situation of the semi-coke tail gas, the purified hydrogen is recovered from the semi-coke tail gas, and the semi-coke tail gas needs to be subjected to process steps such as purification, compression, desulfurization, hydrogen purification and the like, and a conversion step is sometimes included after the compression step. The composition of the semi-coke tail gas after conversion is shown in table 2:
TABLE 2 typical composition of semi-coke tail gas after shift
| Composition of | CO2 | C2+ | N2 | CH4 | CO | H2 | O2 | ∑ |
| Content (V%) | 22.5 | 1 | 36 | 7 | 1 | 32 | 0.50 | 100.00 |
The semi-coke tail gas has low hydrogen content and high impurity gas content, even after conversion, the concentration of the impurity gas except hydrogen is close to 70%, compared with other gas sources for recovering and purifying hydrogen, the semi-coke tail gas has strong specificity, and the recovery and purification of hydrogen from the semi-coke tail gas is also particularly difficult. The composition of the semi-coke tail gas compared with other common gas sources is shown in table 3:
TABLE 3 comparison of the composition of semi-coke tail gas with other common gas sources
| H2Content (V%) | N2Content (V%) | |
| Hydrogen production from semi-coke tail gas (after conversion) | 32 | 36 |
| Coke oven gas hydrogen stripping | 58 | 3.2 |
| Hydrogen production by natural gas conversion | 74 | 0.03 |
| Shift gas stripping of hydrogen | 73 | 0.6 |
| Hydrogen is extracted from methanol purge gas | 60 | 2.6 |
According to the requirement of tar hydrogenation on hydrogen purity, the hydrogen purity is generally required to be more than 99%, and CO in hydrogen2Is not more than 20ppm (volume percentage). In order to purify hydrogen to the extent of meeting the tar hydrogenation requirement, the hydrogen yield of the product obtained by recovering purified hydrogen from semi-coke tail gas is often very low, generally only about 80%. On the premise of meeting the requirement of hydrogen purity, how to improve the yield of the product hydrogen is a great difficulty in recovering and purifying hydrogen from semi-coke tail gas.
In addition, since the semi-coke tail gas has a particularly low pressure, which is generally only a few kPa (the pressure in this document is a gauge pressure), and the operating pressure of the subsequent hydrogen purification process is generally 1.0 to 2.5MPa, the semi-coke tail gas must be compressed and pressurized, and the gas content of the semi-coke tail gas is particularly large, which is generally more than 100000Nm3The energy consumption of the compression and pressure increasing process is high and can reach 1.1 to 104kw is higher than that, and the energy consumption of the semi-coke tail gas recycling whole process is at least 75%. Therefore, how to reduce the energy consumption of the compression step is another difficulty in recovering and purifying hydrogen from the semi-coke tail gas.
The two difficulties can greatly reduce the economic benefit of hydrogen recovery and purification from semi-coke tail gas, thereby causing semi-coke production enterprises to lack the enthusiasm of hydrogen recovery and purification from semi-coke tail gas. Meanwhile, the two difficulties are mutually restricted, and in order to reduce the compression energy consumption, the pressure of the semi-coke tail gas after compression is generally required to be reduced, but the hydrogen yield is reduced; to increase the hydrogen yield, it is generally necessary to increase the operating pressure of the hydrogen purification process, which in turn leads to an increase in the energy consumption of the compression.
In the conventional thinking of the skilled person, even if it is accidentally thought to lower the adsorption pressure of the first stage pressure swing adsorption unitThe energy consumption is reduced, but the hydrogen yield is greatly reduced after the adsorption pressure of the first stage pressure swing adsorption device is reduced, so that the further implementation of the idea is restricted. In the aspect of purge gas selection of the pressure swing adsorption device, the purge gas of the pressure swing adsorption device is generally used as the purge gas; in selecting the adsorbent, a silica gel-type adsorbent is conventionally used for removing CO2Even if an activated carbon adsorbent is used, the volume ratio of the activated carbon adsorbent to the total amount of the adsorbent is small, and generally does not exceed 30%.
Chinese patent No. CN 103275777A discloses 'a method for preparing hydrogen and liquefied natural gas from raw gas of a gas retort', CN 108117047A discloses 'low-pressure sulfur-tolerant shift for preparing hydrogen from raw gas and a special adsorbent inerting-discharging technology', CN 107758615A discloses 'a method for preparing hydrogen from raw gas with low energy consumption and high yield', and CN 108609582A discloses 'a process for preparing hydrogen from raw gas', wherein although two-stage pressure swing adsorption methods are also adopted to purify hydrogen, the first-stage pressure swing adsorption and the second-stage pressure swing adsorption are not organically combined, so that a vacuum pump is often used for vacuumizing regeneration in the first-stage pressure swing adsorption, a large amount of energy consumption is consumed, the impurity gas removal rate is low, and the total yield of hydrogen is low.
Disclosure of Invention
The invention aims to provide a method for recovering and purifying hydrogen from semi-coke tail gas, which has high hydrogen yield and low energy consumption and particularly has obvious economic benefit aiming at the technical difficulty of recovering and purifying hydrogen from semi-coke tail gas according to the actual situation of the semi-coke tail gas.
In order to achieve the above purpose, the specific technical scheme of the invention is as follows:
a method for recovering purified hydrogen from semi-coke tail gas comprises the following steps:
after the semi-coke tail gas is subjected to the working procedures of purification, first compression (compression I), desulfurization and the like, the semi-coke tail gas enters a two-section pressure swing adsorption hydrogen purification device under the lower pressure of 0.3-1.0 MPa, the first pressure swing adsorption device (PSA I) is regenerated by using a flushing method, and flushing gas is part of desorbed gas of a second pressure swing adsorption deviceThe first pressure swing adsorption device can adsorb most of CO in semi-coke tail gas2、C2+Removing, while also removing part of N2、CO、CH4Waiting for impurity gas to obtain H2And N2Primarily clean gas, CO in clean gas2Volume content less than 0.1%, C2+The volume content is lower than 0.01 percent; the purified gas is subjected to secondary compression (compression II) and pressure rise, enters a second-stage pressure swing adsorption device (PSA II) under the higher pressure of 1.0-2.5 MPa, and the residual impurity gas in the purified gas is removed to obtain H2The purity of the product hydrogen is more than or equal to 99 percent, and CO in the product hydrogen2The sum of the volume contents of the components is less than or equal to 20 ppm.
As a preferred embodiment in the present application, the adsorbent filled in the first stage pressure swing adsorption device is activated alumina, silica gel, activated carbon, copper-loaded adsorbent and 13X molecular sieve, and the adsorbent is calculated by volume percentage: the content of the activated alumina is 0-10%, the content of the silica gel is 0-15%, the content of the activated carbon is 50-95%, the content of the copper-loaded adsorbent is 0-30%, the content of the 13X molecular sieve is 5-40%, and the sum of the percentage of the components is 100%.
As a preferred embodiment in the present application, the adsorbents loaded in the second stage of the pressure swing adsorption device are 13X molecular sieve, copper-loaded adsorbent and 5A molecular sieve, and the volume percentage content is as follows: the content of the 5A molecular sieve is 60-100%, the content of the copper-loaded adsorbent is 0-10%, the content of the 13X molecular sieve is 0-40%, and the sum of the percentage of the components is 100%. Wherein the copper-loaded adsorbent is an adsorbent loaded with monovalent copper ions, and the carrier is a molecular sieve or activated carbon
As a preferred embodiment of the present application, the adsorbent filled in the first stage of the pressure swing adsorption device is activated carbon adsorbent with specific surface area greater than 800m2/g。
As a better implementation mode in the application, purified gas enters a second-stage pressure swing adsorption device under the pressure of 1.5-2.0 MPa after being compressed and boosted for the second time.
As a preferred embodiment of the present invention, the first compression step is followed by a conversion step.
As a preferred embodiment in this application, CO and CO in the product hydrogen2The sum of the volume contents of the components is less than or equal to 10 ppm.
A system for recovering and purifying hydrogen from semi-coke tail gas comprises a first pressure swing adsorption device (PSA I) and a second pressure swing adsorption device (PSA II), wherein the first pressure swing adsorption device and the second pressure swing adsorption device are connected in series, a compression device is arranged between the first pressure swing adsorption device and the second pressure swing adsorption device, a non-adsorption phase outlet of the first pressure swing adsorption device is connected with an inlet of the compression device, an outlet of the compression device is connected with an inlet of the second pressure swing adsorption device, and a desorption gas outlet of the second pressure swing adsorption device is connected with the first pressure swing adsorption device.
As a better implementation mode in the application, the semi-coke tail gas device is connected with a section of pressure swing adsorption device, a purification device, a primary compression device and a desulfurization device are sequentially arranged in the connection path of the semi-coke tail gas device and the section of pressure swing adsorption device, and finally the desulfurization device is connected with the inlet of the section of pressure swing adsorption device. Namely, the semi-coke tail gas firstly enters a purification device to remove impurities such as tar, naphthalene, dust and the like, then enters a primary compression device to increase the pressure to about 0.5-1.0 MPa, then enters a desulfurization device to be desulfurized, and passes through CO and H2O reaction to produce CO2And H2. After passing through purification and desulfurization devices, the semi-coke tail gas enters a section of pressure swing adsorption device for pressure swing adsorption treatment.
As a better implementation mode in the application, a conversion device can be arranged behind the primary compression device, namely, the semi-coke tail gas device is connected with a section of pressure swing adsorption device, a purification device, the primary compression device, the conversion device and a desulfurization device are sequentially arranged in the connection path of the semi-coke tail gas device and the section of pressure swing adsorption device, and finally, the desulfurization device is connected with the inlet of the section of pressure swing adsorption device.
In a preferred embodiment of the present application, the first pressure swing adsorption unit and the second pressure swing adsorption unit each include an adsorption tower, and the number of the adsorption towers of each pressure swing adsorption unit is not less than 2. And adsorbent beds are arranged in the adsorption towers of the first-stage pressure swing adsorption device and the second-stage pressure swing adsorption device, and adsorbents are filled in the adsorbent beds.
As a preferred embodiment in the present application, the first pressure swing adsorption device and the second pressure swing adsorption device both include a program control valve and an automatic control system.
As a preferred embodiment in this application, the stripping gas outlet of the one-stage pressure swing adsorption unit is connected to the waste gas line.
As a preferred embodiment in this application, the desorbed gas outlet of the two-stage pressure swing adsorption unit is connected to the waste gas line in addition to the first-stage pressure swing adsorption unit. I.e. the stripping gas from the second stage of pressure swing adsorption unit, one part can be used as flushing gas for the first stage of pressure swing adsorption unit, and the other part is discharged through the waste gas pipeline.
Compared with the prior art, the invention has the following positive effects:
the first-stage pressure swing adsorption and the second-stage pressure swing adsorption are organically combined, the first-stage pressure swing adsorption device is regenerated by using a flushing method, flushing gas is partial desorption gas of the second-stage pressure swing adsorption device, the first-stage pressure swing adsorption device can remove most of impurity gas in semi-coke tail gas, and CO is removed2The removal rate is more than 99.7 percent, the total removal rate of impurity gases except hydrogen is more than 58 percent, and H2The yield is more than 97 percent, not only saves a large amount of energy consumption of a vacuum pump, but also has the characteristics of high impurity gas removal rate and high hydrogen yield;
the second stage pressure swing adsorption device removes most of impurity gases (the total removal rate of the impurity gases except hydrogen is more than 58%), so that the gas quantity needing to be compressed and boosted is greatly reduced during the second compression, and the energy consumption of the compressor is greatly saved;
(III) product H obtained by the two-stage pressure swing adsorption device of the invention2Purity is more than 99%, and CO in product hydrogen2The sum of the volume contents of the two sections of pressure swing adsorption devices is less than or equal to 20ppm, and the H of the two sections of pressure swing adsorption devices2The total yield is more than 93 percent, and the product H is prepared2High yield, low energy consumption and particularly remarkable economic benefitAnd (4) point.
Drawings
FIG. 1 is a schematic view of the process flow employed in example 1 of the present invention.
Fig. 2 is a schematic view of the process flow employed in examples 2, 3 and 5 of the present invention.
FIG. 3 is a schematic diagram of the apparatus involved in the process of example 1 of the present invention.
Fig. 4 is a schematic structural diagram of the device involved in the processes of example 2, example 3 and example 5 in the invention.
Wherein, 1-purification device, 2-first compression device, 3-desulphurization device, 4-first pressure swing adsorption device, 5-second compression device, 6-second pressure swing adsorption device, and 7-transformation device.
Detailed Description
A method for recovering purified hydrogen from semi-coke tail gas comprises the following steps:
after the semi-coke tail gas is subjected to the working procedures of purification, first compression (compression I), desulfurization and the like, the semi-coke tail gas enters a two-section pressure swing adsorption hydrogen purification device under the lower pressure of 0.3-1.0 MPa, the first pressure swing adsorption device (PSA I) is regenerated by using a flushing method, flushing gas is partial desorption gas of the second pressure swing adsorption device, and the first pressure swing adsorption device can be used for enabling most of CO in the semi-coke tail gas to be absorbed by the first pressure swing adsorption device2、C2+Removing, while also removing part of N2、CO、CH4Waiting for impurity gas to obtain H2And N2Primarily clean gas, CO in clean gas2Volume content less than 0.1%, C2+The volume content is lower than 0.01 percent; the purified gas is subjected to secondary compression (compression II) and pressure rise, enters a second-stage pressure swing adsorption device (PSA II) under the higher pressure of 1.0-2.5 MPa, and the residual impurity gas in the purified gas is removed to obtain H2The purity of the product hydrogen is more than or equal to 99 percent, and CO in the product hydrogen2The sum of the volume contents of the components is less than or equal to 20 ppm.
Preferably, the adsorbent filled in the first pressure swing adsorption device is activated alumina, silica gel, activated carbon, copper-loaded adsorbent and 13X molecular sieve, and the adsorbent is prepared from the following components in percentage by volume: the content of the activated alumina is 0-10%, the content of the silica gel is 0-15%, the content of the activated carbon is 50-95%, the content of the copper-loaded adsorbent is 0-30%, the content of the 13X molecular sieve is 5-40%, and the sum of the percentage of the components is 100%.
Preferably, the adsorbents loaded in the second stage of pressure swing adsorption device are 13X molecular sieve, copper-loaded adsorbent and 5A molecular sieve, and the volume percentage content is as follows: the content of the 5A molecular sieve is 60-100%, the content of the copper-loaded adsorbent is 0-10%, the content of the 13X molecular sieve is 0-40%, and the sum of the percentage of the components is 100%. Wherein the copper-loaded adsorbent is an adsorbent loaded with monovalent copper ions, and the carrier is a molecular sieve or activated carbon
Preferably, the adsorbent filled in the first-stage pressure swing adsorption device is an activated carbon adsorbent, and the specific surface area of the activated carbon adsorbent is more than 800m2/g。
Preferably, the purified gas is subjected to secondary compression and pressure increase, and then enters a second-stage pressure swing adsorption device under the pressure of 1.5-2.0 MPa.
Preferably, the first compression step is followed by a conversion step.
Preferably, CO and CO in the product hydrogen2The sum of the volume contents of the components is less than or equal to 10 ppm.
A system for recovering and purifying hydrogen from semi-coke tail gas comprises a first pressure swing adsorption device (PSA I) and a second pressure swing adsorption device (PSA II), wherein the first pressure swing adsorption device and the second pressure swing adsorption device are connected in series, a compression device is arranged between the first pressure swing adsorption device and the second pressure swing adsorption device, a non-adsorption phase outlet of the first pressure swing adsorption device is connected with an inlet of the compression device, an outlet of the compression device is connected with an inlet of the second pressure swing adsorption device, and a desorption gas outlet of the second pressure swing adsorption device is connected with the first pressure swing adsorption device.
Preferably, the semi-coke tail gas device is connected with a section of pressure swing adsorption device, a purification device, a primary compression device and a desulfurization device are sequentially arranged in the connection route of the semi-coke tail gas device and the section of pressure swing adsorption device, and finally the desulfurization device is connected with the inlet of the section of pressure swing adsorption device. I.e. semi cokeThe tail gas firstly enters a purification device to remove impurities such as tar, naphthalene, dust and the like, then enters a primary compression device to increase the pressure to about 0.5-1.0 MPa, then enters a desulfurization device to be desulfurized, and is subjected to CO and H2O reaction to produce CO2And H2. After passing through purification and desulfurization devices, the semi-coke tail gas enters a section of pressure swing adsorption device for pressure swing adsorption treatment.
Preferably, a conversion device can be arranged behind the primary compression device, namely the semi-coke tail gas device is connected with the first pressure swing adsorption device, the purification device, the primary compression device, the conversion device and the desulfurization device are sequentially arranged in the connection path of the semi-coke tail gas device and the first pressure swing adsorption device, and finally the desulfurization device is connected with the inlet of the first pressure swing adsorption device.
Preferably, the first pressure swing adsorption device and the second pressure swing adsorption device both comprise adsorption towers, and the number of the adsorption towers of each pressure swing adsorption device is more than or equal to 2. And adsorbent beds are arranged in the adsorption towers of the first-stage pressure swing adsorption device and the second-stage pressure swing adsorption device, and adsorbents are filled in the adsorbent beds.
Preferably, the first pressure swing adsorption device and the second pressure swing adsorption device both comprise a program control valve and an automatic control system which are matched with each other.
Preferably, the stripping gas outlet of the one-stage pressure swing adsorption unit is connected to the waste gas line.
Preferably, the desorbed gas outlet of the two-stage pressure swing adsorption unit is connected to the waste gas line in addition to the first-stage pressure swing adsorption unit. I.e. the stripping gas from the second stage of pressure swing adsorption unit, one part can be used as flushing gas for the first stage of pressure swing adsorption unit, and the other part is discharged through the waste gas pipeline.
By the method, the main index pair ratio of the invention and the prior art is shown in table 4:
TABLE 4 comparison of the main indicators of the present invention with those of the prior art
The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention. It is to be noted that the features in the following embodiments and examples may be combined with each other without conflict.
It should be noted that, in order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some embodiments of the present invention, but not all embodiments. The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.
In addition, it should be noted that, in the present invention, if the specific structures, connection relationships, position relationships, power source relationships, and the like are not written in particular, the structures, connection relationships, position relationships, power source relationships, and the like related to the present invention can be known by those skilled in the art without creative work on the basis of the prior art.
Example 1:
the method for recovering and purifying hydrogen from semi-coke tail gas in the embodiment adopts a process flow chart with reference to fig. 1, and comprises the following specific steps:
after the semi-coke tail gas is subjected to the working procedures of purification, first compression, desulfurization and the like, the sulfur content is reduced to 10ppm, and the gas enters a two-stage pressure swing adsorption hydrogen purification device under the pressure of 0.7 MPa. The adsorbent filled in the first stage of pressure swing adsorption device (PSA I) is activated carbon, copper-loaded adsorbent and 13X molecular sieve, and the adsorbent comprises the following components in percentage by volume: the content of the activated carbon is 62 percent, the content of the copper-loaded adsorbent is 18 percent, and the content of the 13X molecular sieve is 20 percent. The first stage of pressure swing adsorption device comprises adsorption, three-time pressure equalizing drop, reverse discharge, flushing, three-time pressure equalizing rise and final chargingThe process step is that the flushing gas is the partial desorption gas of the second section of pressure swing adsorption device, the adsorption pressure is 0.7MPa, and the operation temperature is normal temperature. The first-stage pressure swing adsorption device can adsorb most of CO in semi-coke tail gas2、C2+Removing, while also removing part of N2、CO、CH4Waiting for impurity gas to obtain H2And N2Mainly purified gas. Purified gas, CO, obtained from PSA I20.03% by volume of C2+Volume content of 0, CO2The removal rate is 99.85%, the total removal rate of impurity gases except hydrogen is 60.80%, and the hydrogen yield is 97.10%.
After most of impurity gases are removed, purified gas enters a second compression process, the pressure is increased to 1.5Mpa and then enters a second section of pressure swing adsorption device (PSA II), and adsorbents filled in the PSA II are 13X molecular sieves and 5A molecular sieves, and the adsorption process comprises the following steps: the content of the 5A molecular sieve is 85 percent, and the content of the 13X molecular sieve is 15 percent. The second stage of pressure swing adsorption device comprises the process steps of adsorption, five-time pressure drop, reverse discharge, evacuation, five-time pressure rise and final filling, wherein the adsorption pressure is 1.5MPa, the evacuation pressure is-0.08 MPa, and the operation temperature is normal temperature. Product H obtained from PSA II2Purity of 99%, product H2Neutralizing CO and CO2The sum of the volume contents of the two sections of pressure swing adsorption devices is 5ppm, the hydrogen yield of the second section of pressure swing adsorption device is 95.8 percent, and the H of the two sections of pressure swing adsorption devices2The total yield was 93.02%. The tail gas flow of the semi-coke after conversion and desulfurization is 100000Nm3The energy consumption is about 13193kw calculated by/h.
The gas flow rate and the volume content change in each stage are shown in Table 5 (with a semi-coke tail gas flow rate after desulfurization changed to 100000Nm3Calculated by/h):
TABLE 5 gas flowrate and volumetric content Change Table for example 1
Example 2:
the method for recovering and purifying hydrogen from semi-coke tail gas in the embodiment comprises the following steps:
after the semi-coke tail gas is subjected to the working procedures of purification, first compression, transformation, desulfurization and the like, the sulfur content is reduced to 10ppm, and the semi-coke tail gas enters a two-section pressure swing adsorption hydrogen purification device under the pressure of 0.7 MPa. The adsorbent filled in the first-stage pressure swing adsorption device (PSA I) is activated alumina, activated carbon and 13X molecular sieve, and the adsorbent comprises the following components in percentage by volume: the content of the activated alumina is 3 percent, the content of the activated carbon is 82 percent, and the content of the 13X molecular sieve is 15 percent. The first stage pressure swing adsorption device comprises the process steps of adsorption, three-time pressure equalizing drop, reverse releasing, flushing, three-time pressure equalizing rise and final filling, flushing gas is partial desorption gas of the second stage pressure swing adsorption device, the adsorption pressure is 0.7MPa, and the operation temperature is normal temperature. The first-stage pressure swing adsorption device can adsorb most of CO in semi-coke tail gas2、C2+Removing, while also removing part of N2、CO、CH4Waiting for impurity gas to obtain H2And N2Mainly purified gas. Purified gas, CO, obtained from PSA I20.1% by volume of C2+Volume content of 0, CO2The removal rate was 99.74%, the total removal rate of impurity gases other than hydrogen was 58.24%, and the hydrogen yield was 97.67%.
After most of impurity gases are removed, purified gas enters a second compression process, the pressure is increased to 2.0Mpa and then enters a second section of pressure swing adsorption device (PSA II), and adsorbents filled in the PSA II are 13X molecular sieves and 5A molecular sieves, and the adsorption process comprises the following steps: the content of the 5A molecular sieve is 80 percent, and the content of the 13X molecular sieve is 20 percent. The second stage pressure swing adsorption device comprises the process steps of adsorption, six times of pressure drop equalization, reverse discharge, evacuation, six times of pressure rise equalization and final filling, wherein the adsorption pressure is 2.0MPa, the evacuation pressure is-0.08 MPa, and the operation temperature is normal temperature. Product H obtained from PSA II2Purity of 99%, product H2Neutralizing CO and CO2The sum of the volume contents of the two sections of pressure swing adsorption devices is 6ppm, the hydrogen yield of the second section of pressure swing adsorption device is 96.61 percent, and the H of the two sections of pressure swing adsorption devices2The total yield was 94.36%. The tail gas flow of the semi-coke after conversion and desulfurization is 100000Nm3The energy consumption is about 14109 kw/h.
The changes in gas flow rate and volume content at each stage are shown in Table 6 (in terms of variation)The flow rate of the semi-coke tail gas after the exchange desulfurization is 100000Nm3Calculated by/h):
table 6 table showing changes in gas flow rate and volume content of example 2
Example 3:
the method for recovering and purifying hydrogen from semi-coke tail gas in the embodiment comprises the following steps:
after the semi-coke tail gas is subjected to the working procedures of purification, first compression, transformation, desulfurization and the like, the sulfur content is reduced to 120ppm, and the semi-coke tail gas enters a two-section pressure swing adsorption hydrogen purification device under the pressure of 0.7 MPa. The adsorbent filled in the first-stage pressure swing adsorption device (PSA I) is activated alumina, silica gel, activated carbon and 13X molecular sieve, and the adsorbent comprises the following components in percentage by volume: the content of the activated alumina is 5%, the content of the silica gel is 10%, the content of the activated carbon is 65%, and the content of the 13X molecular sieve is 20%. The first stage pressure swing adsorption device comprises the process steps of adsorption, three-time pressure equalizing drop, reverse releasing, flushing, three-time pressure equalizing rise and final filling, flushing gas is partial desorption gas of the second stage pressure swing adsorption device, the adsorption pressure is 0.7MPa, and the operation temperature is normal temperature. The first-stage pressure swing adsorption device can adsorb most of CO in semi-coke tail gas2、C2+Removing, while also removing part of N2、CO、CH4The impurity gas is equal, in addition, the first stage pressure swing adsorption device can tolerate and remove sulfur, and H is obtained2And N2Mainly purified gas. Purified gas, CO, obtained from PSA I20.08% by volume of C2+Volume content of 0, CO2The removal rate was 99.79%, the total removal rate of impurity gases other than hydrogen was 59.02%, and the hydrogen yield was 97.05%.
After most of impurity gases are removed, purified gas enters a second compression process, the pressure is increased to 1.7Mpa and then enters a second section of pressure swing adsorption device (PSA II), and adsorbents filled in the PSA II are 13X molecular sieves and 5A molecular sieves, and the adsorption process comprises the following steps: the content of the 5A molecular sieve is 90 percent, and the content of the 13X molecular sieve is 10 percent. Second-stage pressure swing adsorption deviceComprises the steps of adsorption, five-time pressure drop equalization, reverse discharge, evacuation, five-time pressure rise equalization and final filling, wherein the adsorption pressure is 1.7MPa, the evacuation pressure is-0.08 MPa, and the operation temperature is normal temperature. Product H obtained from PSA II2Purity of 99%, product H2Neutralizing CO and CO2The sum of the volume contents of the two sections of pressure swing adsorption devices is 3ppm, the hydrogen yield of the second section of pressure swing adsorption device is 96.26 percent, and the H of the two sections of pressure swing adsorption devices2The overall yield was 93.42%. The tail gas flow of the semi-coke after conversion and desulfurization is 100000Nm3The energy consumption is about 13872kw calculated by/h.
The gas flow rate and the volume content change in each stage are shown in Table 7 (with a semi-coke tail gas flow rate after desulfurization changed to 100000Nm3Calculated by/h):
TABLE 7 table of gas flow and volume content changes of example 3
Example 4:
the method for recovering and purifying hydrogen from semi-coke tail gas in the embodiment comprises the following steps:
after being purified, the semi-coke tail gas is directly compressed to 1.7MPa, and then enters a two-section pressure swing adsorption hydrogen purification device after the procedures of transformation, desulfurization and the like are carried out. The adsorbent filled in the first-stage pressure swing adsorption device (PSA I) is activated alumina, silica gel, activated carbon and 13X molecular sieve, and the adsorbent comprises the following components in percentage by volume: the content of the activated alumina is 5%, the content of the silica gel is 10%, the content of the activated carbon is 65%, and the content of the 13X molecular sieve is 20%. The first stage pressure swing adsorption device comprises the process steps of adsorption, three-time pressure equalizing drop, reverse releasing, flushing, three-time pressure equalizing rise and final charging, flushing gas is self-discharged gas of the first stage pressure swing adsorption device, the adsorption pressure is 1.7MPa, and the operation temperature is normal temperature. Purified gas, CO, obtained from PSA I20.08% by volume of C2+The content by volume is 0, and the content by volume is,CO2the removal rate was 99.82%, and the hydrogen yield was 83.14%.
After most of impurity gases are removed, the purified gas enters a second section of pressure swing adsorption device (PSA II), and adsorbents filled in the PSA II are 13X molecular sieves and 5A molecular sieves, and the adsorption agent comprises the following components in percentage by volume: the content of the 5A molecular sieve is 90 percent, and the content of the 13X molecular sieve is 10 percent. The second stage of pressure swing adsorption device comprises the process steps of adsorption, five-time pressure drop, reverse discharge, evacuation, five-time pressure rise and final filling, wherein the adsorption pressure is 1.7MPa, the evacuation pressure is-0.08 MPa, and the operation temperature is normal temperature. Product H obtained from PSA II2Purity of 99%, product H2Neutralizing CO and CO2The sum of the volume contents of the two sections of pressure swing adsorption devices is 3ppm, the hydrogen yield of the second section of pressure swing adsorption device is 96.37 percent, and the H of the two sections of pressure swing adsorption devices2The overall yield was 80.12%. The tail gas flow of the semi-coke after conversion and desulfurization is 100000Nm3Calculated by/h, the energy consumption is about 15966 kw.
The gas flow rate and the volume content change in each stage are shown in Table 8 (with a semi-coke offgas flow rate after desulfurization changed to 100000Nm3Calculated by/h):
table 8 table of gas flow rate and volume content change of example 4
Example 5:
the method for recovering and purifying hydrogen from semi-coke tail gas in the embodiment comprises the following steps:
after the semi-coke tail gas is subjected to the working procedures of purification, first compression, transformation, desulfurization and the like, the sulfur content is reduced to 10ppm, and the semi-coke tail gas enters a two-section pressure swing adsorption hydrogen purification device under the pressure of 0.7 MPa. The adsorbent filled in the first-stage pressure swing adsorption device (PSA I) is activated alumina, silica gel and activated carbon, and the adsorbent comprises the following components in percentage by volume: the content of activated alumina is 5%, the content of silica gel is 65%, and the content of activated carbon is 30%. The first section of pressure swing adsorption device comprises the process steps of adsorption, three times of pressure equalizing and reducing, reverse releasing, flushing, three times of pressure equalizing and increasing and final charging, flushing gas is partial desorption gas of the second section of pressure swing adsorption device,the adsorption pressure is 0.7MPa, and the operation temperature is normal temperature. Purified gas, CO, obtained from PSA I2Volume content of 1.39%, C2+Volume content of 0.11, CO2The removal rate was 95.69%, the total removal rate of impurity gases other than hydrogen was 37.18%, and the hydrogen yield was 88.84%.
After removing part of impurity gas, the purified gas enters a second compression process, the pressure is increased to 1.7Mpa, and then the purified gas enters a second section of pressure swing adsorption device (PSA II), and adsorbents filled in the PSA II are 13X molecular sieves and 5A molecular sieves, and are calculated by volume percentage: the content of the 5A molecular sieve is 90 percent, and the content of the 13X molecular sieve is 10 percent. The second stage of pressure swing adsorption device comprises the process steps of adsorption, five-time pressure drop, reverse discharge, evacuation, five-time pressure rise and final filling, wherein the adsorption pressure is 1.7MPa, the evacuation pressure is-0.08 MPa, and the operation temperature is normal temperature. Product H obtained from PSA II2Purity of 99%, product H2Neutralizing CO and CO2The sum of the volume contents of the two sections of pressure swing adsorption devices is 18ppm, the hydrogen yield of the second section of pressure swing adsorption device is 91.90 percent, and the H of the two sections of pressure swing adsorption devices2The total yield was 81.65%. The tail gas flow of the semi-coke after conversion and desulfurization is 100000Nm3The energy consumption is about 14484kw calculated by/h.
The gas flow rate and the volume content change in each stage are shown in Table 9 (with the semi-coke tail gas flow rate after desulfurization changed to 100000Nm3Calculated by/h):
TABLE 9 table of gas flow and volume content changes of example 5
The foregoing basic embodiments of the invention and their various further alternatives can be freely combined to form multiple embodiments, all of which are contemplated and claimed herein. In the scheme of the invention, each selection example can be combined with any other basic example and selection example at will. Numerous combinations will be known to those skilled in the art.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.
Claims (9)
1. A method for recovering and purifying hydrogen from semi-coke tail gas is characterized by comprising the following steps: after the semi-coke tail gas is subjected to purification, first compression and desulfurization processes, the semi-coke tail gas enters a two-section pressure swing adsorption hydrogen purification device under the lower pressure of 0.3-1.0 MPa, the first pressure swing adsorption device is regenerated by using a flushing method, flushing gas is partial desorption gas of a second pressure swing adsorption device, and the first pressure swing adsorption device enables most of CO in the semi-coke tail gas to be absorbed by the first pressure swing adsorption device2、C2+Removing, while also removing part of the N2、CO、CH4Waiting for impurity gas to obtain H2And N2A predominantly purge gas; the purified gas is compressed and pressurized for the second time, enters a second-stage pressure swing adsorption device under the higher pressure of 1.0-2.5 MPa, and the residual impurity gas in the purified gas is removed to obtain H2The purity of the product hydrogen is more than or equal to 99 percent, and CO in the product hydrogen2The sum of the volume contents of the components is less than or equal to 20 ppm.
2. The method for recovering and purifying hydrogen from semi-coke tail gas according to claim 1, characterized in that: purifying CO in gas2Volume content less than 0.1%, C2+The volume content is less than 0.01 percent.
3. The method for recovering and purifying hydrogen from semi-coke tail gas according to claim 1, characterized in that: the adsorbent filled in the adsorption tower in the first stage of pressure swing adsorption device is activated alumina, silica gel, activated carbon, copper-loaded adsorbent and 13X molecular sieve, and the content of the activated alumina is 0-10 percent, the content of the silica gel is 0-15 percent, the content of the activated carbon is 50-95 percent, the content of the copper-loaded adsorbent is 0-30 percent, the content of the 13X molecular sieve is 5-40 percent, and the sum of the percentage of all the components is 100 percent; the copper-loaded adsorbent is an adsorbent loaded with monovalent copper ions, and the carrier is a molecular sieve or activated carbon.
4. The method for recovering and purifying hydrogen from semi-coke tail gas according to claim 1, characterized in that: the adsorbents filled in the adsorption tower in the second stage of pressure swing adsorption device are a 13X molecular sieve, a copper-loaded adsorbent and a 5A molecular sieve, and by volume percentage, the content of the 5A molecular sieve is 60-100%, the content of the copper-loaded adsorbent is 0-10%, the content of the 13X molecular sieve is 0-40%, and the sum of the percentages of all the components is 100%; the copper-loaded adsorbent is an adsorbent loaded with monovalent copper ions, and the carrier is a molecular sieve or activated carbon.
5. The method for recovering and purifying hydrogen from semi-coke tail gas according to any one of claims 1-3, characterized in that: the specific surface area of the activated carbon adsorbent filled in the first stage pressure swing adsorption device is more than 800m2/g。
6. The method for recovering and purifying hydrogen from semi-coke tail gas according to claim 1, characterized in that: after the semi-coke tail gas is subjected to purification, first compression and desulfurization processes, the semi-coke tail gas enters a two-section pressure swing adsorption hydrogen purification device under the lower pressure of 0.5-0.8 MPa.
7. The method for recovering and purifying hydrogen from semi-coke tail gas according to claim 1, characterized in that: and (4) compressing and boosting the purified gas for the second time, and feeding the purified gas into a second-stage pressure swing adsorption device under the pressure of 1.5-2.0 MPa.
8. The method for recovering and purifying hydrogen from semi-coke tail gas according to claim 1, characterized in that: after the first compression step, a conversion step is also included.
9. The method for recovering and purifying hydrogen from semi-coke tail gas according to claim 1, characterized in that: CO and CO in product hydrogen2The sum of the volume contents of the components is less than or equal to 10 ppm.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115253595A (en) * | 2022-08-16 | 2022-11-01 | 瑞必科净化设备（上海）有限公司 | System for purifying hydrogen with backflow through two-stage pressure swing adsorption, method for purifying hydrogen and application |
| CN115321484A (en) * | 2022-08-16 | 2022-11-11 | 瑞必科净化设备（上海）有限公司 | System for purifying hydrogen by two-stage compression and adsorption, method for purifying hydrogen and application |
| WO2024064741A1 (en) * | 2022-09-20 | 2024-03-28 | Uop Llc | Oxyfuel combustion in method of recovering a hydrogen- enriched product and co2 in a hydrogen production unit |
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2021
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115253595A (en) * | 2022-08-16 | 2022-11-01 | 瑞必科净化设备（上海）有限公司 | System for purifying hydrogen with backflow through two-stage pressure swing adsorption, method for purifying hydrogen and application |
| CN115321484A (en) * | 2022-08-16 | 2022-11-11 | 瑞必科净化设备（上海）有限公司 | System for purifying hydrogen by two-stage compression and adsorption, method for purifying hydrogen and application |
| WO2024064741A1 (en) * | 2022-09-20 | 2024-03-28 | Uop Llc | Oxyfuel combustion in method of recovering a hydrogen- enriched product and co2 in a hydrogen production unit |
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