Pressure swing adsorption hydrogen extraction capacity expansion transformation method

Abstract

The invention discloses a pressure swing adsorption hydrogen extraction capacity expansion transformation method, and relates to the technical field of pressure swing adsorption hydrogen extraction, and the method comprises the following steps: pre-configuring an adsorption tower with the tower diameter of DN1600 to 17m, configuring the height of a filler layer to 13m, enabling the adsorbent filling amount of a single tower to be 180m < 3 >, and configuring two layers of stainless steel grids with the spacing of 2.5 m in the adsorption tower for supporting the adsorbent; configuring a feed gas bottom header pipe to be DN200 and a product hydrogen bottom header pipe to be DN150; a raw material gas pipeline is configured for three-tower gas inlet, and a product hydrogen pipeline is configured for four-tower gas outlet. Through the adsorption tower structure optimization and multi-tower cooperative control technology, the capacity is doubled on the premise of not increasing the occupied area of equipment, and the space utilization rate and the equipment integration degree of the device are remarkably improved. According to the collaborative design of tower body extension and adsorbent increment, the problem of equipment layout reconstruction caused by adding a tower body in a traditional capacity expansion scheme is avoided, an original device foundation and a public engineering system can be directly utilized, and the transformation cost and the construction complexity are greatly reduced.

Description

Technical Field

[0001] This invention relates to the field of pressure swing adsorption (PSA) hydrogen extraction technology, and more specifically, to a method for expanding and upgrading the capacity of PSA hydrogen extraction. Background Technology

[0002] In the fields of coal chemical industry and hydrogen purification, pressure swing adsorption (PSA) technology is widely used due to its high efficiency and energy saving. However, traditional PSA hydrogen extraction units often face limitations in equipment structure and excessively high retrofit costs when facing capacity expansion demands. For example, when increasing hydrogen extraction capacity from several thousand cubic meters per hour to over ten thousand cubic meters per hour, traditional solutions typically require adding adsorption towers and expanding the equipment footprint. This not only leads to a surge in investment costs of over 50% but also significantly extends the retrofit cycle, and the energy consumption and management costs of the new equipment also increase accordingly. Simultaneously, the existing unit's piping diameter, valve control logic, and adsorbent loading are prone to technical bottlenecks when handling large flows of feed gas, such as exceeding flow rate limits, pressure fluctuations, and decreased impurity removal efficiency, making it difficult to achieve capacity breakthroughs without large-scale equipment replacement.

[0003] With the rapid growth in industrial hydrogen demand, the expansion and retrofitting of existing PSA hydrogen extraction units faces both technical and economic challenges. On the one hand, doubling the feed gas processing capacity requires adsorption towers with larger packing volumes to meet the impurity removal load, but traditional tower structure designs limit the adsorbent packing space. On the other hand, the hydrodynamic performance of the piping system under high flow conditions urgently needs optimization; the existing DN100-DN125 pipes are insufficient for handling 20,000 Nm³ / h flow rates. 3 At gas flow rates in the range of / h, the flow velocity easily exceeds the safety threshold of 12m / s, leading to pressure instability and equipment wear. Furthermore, technical challenges such as dynamic balance control of the adsorbent under high loads and valve logic optimization for multi-tower coordinated operation are also key factors restricting the efficient capacity expansion of PSA units, necessitating a capacity expansion and retrofit method that balances economic efficiency and technical feasibility.

[0004] No effective solutions have yet been proposed to address the problems in the relevant technologies. Summary of the Invention

[0005] To address the problems in related technologies, this invention proposes a pressure swing adsorption (PSA) hydrogen extraction and energy expansion modification method to overcome the aforementioned technical problems existing in the current related technologies.

[0006] The technical solution of this invention is implemented as follows:

[0007] A method for upgrading and modifying hydrogen extraction capacity using pressure swing adsorption (PSA) includes the following steps:

[0008] An adsorption tower with a diameter of DN1600 is pre-configured to 17m, with a packing layer height of 13m, so that the adsorbent loading of a single tower is 180m3, and a layer of stainless steel grid is installed inside to support the adsorbent.

[0009] The bottom main pipe for raw material gas is configured as DN200, and the bottom main pipe for product hydrogen is configured as DN150.

[0010] Configure the raw material gas pipeline to be the gas inlet of 3 towers and the product hydrogen pipeline to be the gas outlet of 3 towers, and adjust the PLC pressure equalization time to 180s.

[0011] This also includes: the raw gas is a low-temperature methanol wash gas with an H2 content ≥85% and a CO content ≤2%, and is treated with fine desulfurization to make the total sulfur ≤0.1ppm.

[0012] The adsorbent includes: 13X molecular sieve as the adsorbent, with a bulk density ≥800 kg / m³. 3 The CO adsorption capacity is ≥22 mmol / g, and the dynamic adsorption cycle is ≥1200 times under the conditions of 2.3 MPa and 30℃.

[0013] The adsorbent is prepared using a layered filling process, with 80m³ of 13X molecular sieve laid at the bottom and 100m³ of 13X molecular sieve filled at the top.

[0014] The heightening section of the adsorption tower is made of Q345R material with a wall thickness of ≥20mm.

[0015] The bottom main pipe of the raw gas consists of four parallel DN200 pipes, and the single tower inlet valve is controlled by a combination of three DN100 valves, with the gas flow rate controlled at 10-12 m / s.

[0016] The product hydrogen bottom main pipe consists of three parallel DN150 pipes, and the single tower outlet valve is controlled by four sets of DN80 valves, with a flow rate ≤9.8m / s.

[0017] The beneficial effects of this invention are:

[0018] 1. This invention, through optimization of the adsorption tower structure and multi-tower collaborative control technology, doubles the production capacity without increasing the footprint of new equipment, significantly improving the space utilization and equipment integration of the unit. The synergistic design of tower extension and adsorbent increment avoids the equipment layout reconstruction problems caused by adding new towers in traditional capacity expansion schemes, and can directly utilize the existing unit foundation and utility system, greatly reducing the cost of modification and construction complexity. At the same time, the multi-tower split inlet / outlet control strategy effectively balances the system pressure, reduces the impact wear of valves and pipelines, extends the service life of key equipment, and provides a guarantee for the long-term stable operation of the unit.

[0019] 2. This invention combines a feed gas pretreatment process with a high-performance adsorbent, making the device more adaptable to feed gases of different compositions, especially suitable for the purification of low-temperature methanol wash gas in the coal chemical industry. This method does not require changes to the core layout of the original device; capacity can be increased simply through parameter optimization and local modifications. It provides a standardized technical path for the capacity expansion and retrofitting of similar PSA devices and can be widely applied to hydrogen production processes in industries such as synthetic ammonia and methanol, promoting the efficient and low-cost development of hydrogen energy utilization technology. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic flowchart of a pressure swing adsorption hydrogen extraction and energy expansion modification method according to an embodiment of the present invention. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention are within the scope of protection of the present invention.

[0023] According to an embodiment of the present invention, a method for hydrogen extraction and energy expansion through pressure swing adsorption is provided.

[0024] like Figure 1 As shown, the pressure swing adsorption hydrogen extraction and energy expansion method according to an embodiment of the present invention includes the following steps:

[0025] An adsorption tower with a diameter of DN1600 is pre-configured to 17m, with a packing layer height of 13m, so that the adsorbent loading of a single tower is 180m3, and a layer of stainless steel grid is installed inside to support the adsorbent.

[0026] This also includes: the raw gas is a low-temperature methanol wash gas with an H2 content ≥85% and a CO content ≤2%, and is treated with fine desulfurization to make the total sulfur ≤0.1ppm.

[0027] The adsorbent includes: 13X molecular sieve as the adsorbent, with a bulk density ≥800 kg / m³. 3The CO adsorption capacity is ≥22 mmol / g, and the dynamic adsorption cycle is ≥1200 cycles under conditions of 2.3 MPa and 30℃. The adsorbent adopts a layered filling process, with 80 m3 of 13X molecular sieve at the bottom and 100 m3 of 13X molecular sieve at the top.

[0028] The heightening section of the adsorption tower is made of Q345R material with a wall thickness of ≥20mm.

[0029] The bottom main pipe for raw material gas is configured as DN200, and the bottom main pipe for product hydrogen is configured as DN150.

[0030] The raw material gas bottom main pipe consists of four parallel DN200 pipes, and the single-tower inlet valve is controlled by a combination of three DN100 valves, with the gas flow rate controlled at 10-12 m / s. The product hydrogen bottom main pipe consists of three parallel DN150 pipes, and the single-tower outlet valve is controlled by a coordinated combination of four DN80 valves, with a flow rate ≤9.8 m / s.

[0031] Configure the raw material gas pipeline to be the gas inlet of 3 towers and the product hydrogen pipeline to be the gas outlet of 3 towers, and adjust the PLC pressure equalization time to 180s.

[0032] Using the above scheme, low-temperature methanol wash gas is used to replace the original decarbonization gas, reducing the CO load by more than 50%; the feed gas enters the PSA system after fine desulfurization (total sulfur ≤ 0.1 ppm) at a pressure of 2.3 MPa and a temperature of 30°C; simultaneously, the feed gas is distributed to 10 adsorption towers (each tower has a processing capacity of approximately 2300 Nm³) through three DN200 main pipes. 3 Under high pressure (2.3 MPa), 13X molecular sieve preferentially adsorbs impurities such as CO, N2, and CO2, increasing H2 purity to over 99.9%. After modification, the adsorbent loading increased by 125%, CO adsorption capacity increased by 22%, and single-tower adsorption time was extended from 40 s to 43 s. Furthermore, after adsorption saturation, the adsorption tower underwent three pressure equalization cycles (each equalization time 180 s, 50% longer than before the modification) to reduce the pressure to 0.3 MPa. The equalized gas was recovered to the product gas system, improving hydrogen recovery rate (from 88% to 92%). The gas was then released back to atmospheric pressure (0.1 MPa), and the desorbed impurities were discharged into the desorption gas system through a DN250 main pipe for final incineration. Additionally, the purified hydrogen was collected through four DN150 main pipes and output after pressure regulation to 2.2 MPa. Pressure sensors monitor the outlet pressure of each tower in real time, and the PLC system dynamically adjusts valve openings to ensure product gas pressure fluctuations are ≤ ±0.03 MPa.

[0033] Specifically, the implementation process includes the following steps:

[0034] The raw material gas system was modified in advance, including: raw material gas switching and pipeline replacement, among which;

[0035] The feed gas switching process includes: cutting off the original pressure swing adsorption decarbonization gas feed and introducing low-temperature methanol wash gas with the following composition: H2 85.2%, N2 12.3%, CO 1.5%, CO2 0.8%, and total sulfur ≤0.1ppm after fine desulfurization treatment.

[0036] The pipeline replacement includes: replacing the bottom main pipe for raw material gas from DN125 (seamless steel pipe, specification Φ133×4) to DN200 (Φ219×6), using flange connection, pressure rating PN25. The main pipe for product hydrogen is replaced from DN100 (Φ108×4) to DN150 (Φ159×5), with the pipe length adjusted according to the existing layout to ensure a flow velocity ≤10m / s.

[0037] The adsorption tower renovation project includes the following steps: Increasing the tower height by removing the top end cap and constructing a 5m high cylindrical section using Q345R steel plates of the same material. The butt welds will undergo 100% radiographic testing (RT-II level). Two layers of packing support grids will be installed in the new tower section, spaced 2.5m apart, with a grid opening rate of 35% and a load-bearing capacity ≥800kg / m². 2 .

[0038] For adsorbent loading, first load alumina, then load 5m high 13X molecular sieves (particle size 3-5mm), and finally cover with 0.5m high activated carbon (particle size 10-15mm). Vibration loading is used during the process to ensure a bulk density ≥800kg / m³. 3 .

[0039] This also includes: a DN150 spring-loaded safety valve installed at the top of the adsorption tower, with a starting pressure of 2.5 MPa, and the discharge pipeline connected to the flare system. All pipelines and equipment are equipped with anti-static bridging, and the grounding resistance is ≤4Ω.

[0040] The modification of valves and automatic control systems includes the following steps:

[0041] The valve group was modified by adding two sets of DN100 pneumatic programmable valves to the raw material intake system, forming a three-tower intake valve group with the original valves. The opening and closing of the valves are controlled by PLC according to the adsorption cycle sequence. Two new sets of DN20 valves were also added, equipped with pressure sensors to monitor the outlet pressure of each tower in real time.

[0042] The control system was debugged, and the adsorption cycle program was adjusted. The adsorption time was changed from 120s to 129s, the pressure equalization time was extended from 120s to 180s in three stages, and the purging time was increased by 30s. A 72-hour continuous test run was conducted, and the pressure difference in the tower (normal ≤0.2MPa), the purity of the product gas (H2≥99.9%), and the system pressure stability (fluctuation ≤±0.03MPa) were monitored.

[0043] In addition, the specific parameters during implementation are as follows:

[0044] Production capacity target: Average hydrogen production of 20,150 Nm³ after 30 days of continuous operation. 3 / h, fluctuation range ≤±1.2%.

[0045] Purity indicators: CO content: 0.8-1.5 ppm, average 1.2 ppm; Total sulfur: 0.05-0.08 ppm, average 0.06 ppm; Other impurity indicators are all better than design requirements (N2≤0.08%, CO2≤8 ppm). Energy consumption data: Unit energy consumption 0.34 kWh / Nm 3 Compared to 0.35 kWh / Nm before the renovation 3 Basically the same, with no increase in energy consumption.

[0046] Specifically, after incineration, the desorbed gas has a CO content of ≤20ppm and a NOx content of ≤50ppm, meeting the GB16297-1996 Class II emission standard. Meanwhile, the noise level of the modified unit is ≤85dB(A), with a measured value of 82dB(A) at 1m from the unit area, complying with the industrial enterprise boundary environmental noise emission standard.

[0047] In summary, by employing the above-described technical solution of the present invention, the following effects can be achieved:

[0048] 1. This invention, through optimization of the adsorption tower structure and multi-tower collaborative control technology, doubles the production capacity without increasing the footprint of new equipment, significantly improving the space utilization and equipment integration of the unit. The synergistic design of tower extension and adsorbent increment avoids the equipment layout reconstruction problems caused by adding new towers in traditional capacity expansion schemes, and can directly utilize the existing unit foundation and utility system, greatly reducing the cost of modification and construction complexity. At the same time, the multi-tower split inlet / outlet control strategy effectively balances the system pressure, reduces the impact wear of valves and pipelines, extends the service life of key equipment, and provides a guarantee for the long-term stable operation of the unit.

[0049] 2. This invention combines a feed gas pretreatment process with a high-performance adsorbent, making the device more adaptable to feed gases of different compositions, especially suitable for the purification of low-temperature methanol wash gas in the coal chemical industry. This method does not require changes to the core layout of the original device; capacity can be increased simply through parameter optimization and local modifications. It provides a standardized technical path for the capacity expansion and retrofitting of similar PSA devices and can be widely applied to hydrogen production processes in industries such as synthetic ammonia and methanol, promoting the efficient and low-cost development of hydrogen energy utilization technology.

[0050] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Those skilled in the art, upon considering the disclosure in the specification and embodiments, will readily conceive of other embodiments of this disclosure. This application is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not disclosed herein. The specification and embodiments are to be considered exemplary only, and the true scope and spirit of this disclosure are indicated by the claims.

[0051] It should be understood that this disclosure is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this disclosure is limited only by the appended claims.

Claims

1. A method for upgrading and expanding hydrogen production capacity through pressure swing adsorption (PSA), characterized in that, It comprises the following steps: The adsorption tower with a diameter DN1600 is pre-configured to 17 m, the packing layer height is configured to 13 m, the single tower adsorbent loading amount is 180 m3, and one layer of stainless steel grid is configured inside for supporting the adsorbent; The raw material gas bottom manifold is configured to DN200, and the product hydrogen gas bottom manifold is configured to DN150; The raw material gas pipeline is configured to 3-tower gas inlet, and the product hydrogen gas pipeline is configured to 3-tower gas outlet, and the PLC pressure equalization time is adjusted to 180 s.

2. The PSA hydrogen extraction revamp method according to claim 1, characterized in that, It also comprises: The raw material gas adopts low-temperature methanol washing gas, the H2 content is ≥85%, the CO content is ≤2%, and the total sulfur is ≤0.1 ppm after the fine desulfurization treatment.

3. The PSA hydrogen extraction revamp method of claim 1, wherein, The adsorbent includes: using 13X molecular sieve as adsorbent, bulk density ≥ 800 kg / m 3 , CO adsorption capacity ≥ 22 mmol / g, dynamic adsorption cycle ≥ 1200 times at 2.3 MPa, 30°C.

4. The PSA hydrogen extraction revamp method of claim 3, wherein, The adsorbent adopts a layered loading process, 80 m3 of 13X molecular sieve is laid at the bottom, and 100 m3 of 13X molecular sieve is loaded at the top.

5. The PSA hydrogen extraction revamp method of claim 1, wherein, The adsorption tower heightening part adopts Q345R material, and the wall thickness is ≥20 mm.

6. The PSA hydrogen extraction revamp method of claim 1, wherein, The raw material gas bottom manifold is 4 DN200 in parallel, the single tower gas inlet valve adopts 3 groups of DN100 valve combination control, and the gas flow rate control is 10-12 m / s.

7. The PSA hydrogen extraction revamp method of claim 5, wherein, The product hydrogen gas bottom manifold is 3 DN150 in parallel, the single tower gas outlet valve adopts 4 groups of DN80 valve cooperative control, and the flow rate is ≤9.8 m / s.

Images