- Operation: automatic, PLC controlled
- Utilities: For the production of 1,000 Nm³/h H2 from natural gas the following Utilities are required:
- 380-420 Nm³/h natural gas
- 900 kg/h boiler feed water
- 28 kW electric power
- 38 m³/h cooling water *
- * can be substituted by air cooling
- By-product: export steam, if required
Application
To recycle pure H2 from H2-rich gas mixture such as shift gas, refined gas, semi-water gas, city gas, coke-oven gas, fermentation gas, methanol tail gas, formaldehyde tail gas, FCC dry gas of oil refinery, shift tail gas and other gas sources with H2.
Features
1. TCWY devotes to design and build cost-effective Pressure Swing Adsorption Plant with high performance. According to customers’ specific requirements and production characteristics, the most appropriate technical plan, process route, adsorbents types and proportion are provided to ensure the yield of effective gas and the reliability of index.
2. In the operation plan, mature and advanced control software package is adopted to optimize the adsorption time, which enables the plant to operate in the most economical mode for a long time and be free from the influence of technical level and careless operation of operators.
3. Dense filling technology of adsorbents is adopted to further reduce the dead spaces between the bed layers and increasing the recovery rate of the effective components.
4. The lifespan of our PSA programmable valves with special technologies is above 1 million times.
(1) PSA-H2 Plant Adsorption Process
Feed Gas enters adsorption tower from the bottom of the tower (One or several are always in the state of adsorbing). Through the selective adsorption of various adsorbents one after one, the impurities are adsorbed and un-adsorbed H2 flow out from the top of the tower.
When the forward position of mass transfer zone (adsorption forward position) of the adsorption impurity reaches the exit reserved section of the bed layer, turn off the feed valve of the feed gas and the outlet valve of product gas, stop adsorption. And then the adsorbent bed is switched to regeneration process.
(2) PSA-H2 Plant Equal Depressurization
After the adsorption process, along the direction of adsorption put higher-pressure H2 at adsorption tower into other lower pressure adsorption tower which has finished regeneration. The whole process is not only depressurization process, but also the process for recovering H2 of bed dead space. The process includes several times on-stream equal depressurization, so H2 recovery can be fully ensured.
(3) PSA-H2 Plant Pathwise Pressure Release
After equal depressurization process, along the direction of adsorption the product H2 on top of the adsorption tower is quickly recovered into the pathwise pressure release gas buffer tank (PP Gas Buffer Tank), this part of H2 will be used as regeneration gas source of adsorbent depressurization.
(4) PSA-H2 Plant Reverse Depressurization
After pathwise pressure release process, the adsorption forward position has reached the exit of bed layer. At this time, the pressure of adsorption tower is reduced to 0.03 barg or so at the adverse direction of adsorption, large amount of the adsorbed impurities begin to be desorbed from the adsorbent. The reverse depressurization desorbed gas enters the tail gas buffer tank and mix with the purging regeneration gas.
(5) PSA-H2 Plant Purging
After reverse depressurization process, in order to gain the complete regeneration of adsorbent, use the hydrogen of pathwise pressure release gas buffer tank at the adverse direction of adsorption to wash the adsorption bed layer, further decrease the fractional pressure, and the adsorbent can be completely regenerated, this process should be slow and stable so that the good effect of regeneration can be ensured. Purging regeneration gas also enter blowdown tail gas buffer tank. Then it will be sent out of the battery limit and be used as fuel gas.
(6) PSA-H2 Plant Equal Repressurization
After purging regeneration process, use higher-pressure H2 from the other adsorption tower to repressurize the adsorption tower in turn, this process corresponds with the equal-depressurization process, it is not only a process of pressure boosting, but also a process of recovering H2 in the bed dead space of other adsorption tower. The process includes several times on-stream equal-repressure processes.
(7) PSA-H2 Plant Product Gas Final Repressurization
After several times equal repressurization processes, in order to switch the adsorption tower to next adsorption step steadily and to ensure the product purity not to be fluctuated, it needs to use product H2 by boost control valve to raise the pressure of adsorption tower to adsorption pressure slowly and steadily.
After the process, the adsorption towers complete an entire “adsorption-regeneration” cycle, and makes preparation for next adsorption.
