High-purity hydrogen is a crucial raw material in the petrochemical industry, extensively utilized across various domains of petrochemical production. Pressure Swing Adsorption(PSA) is a gas separation and purification technology. Its principle relies on the difference in selective adsorption capabilities of adsorbents toward different gas components under varying partial pressures. Impurity components are preferentially adsorbed and accumulate within the adsorbent, thereby achieving hydrogen purification. Chempack’s adsorbents have high adsorption performance, high selectivity, and long-term stability.
1. Feed and Product
The primary feedstock for PSA is hydrogen gas containing impurities, originating from the Hydrogen Production Unit(HPU). The main target product is hydrogen product with hydrogen purity over 99.9vol% and CO content(CO<10ppmv) and CO2 content(CO2 <10ppmv) meeting specification.
2. Adsorbents Function and Loading
PuriSorb HMS-05 is a clay-bound sodium form of Type A molecular sieve. 5A molecular sieve will adsorb molecules with critical diameters up to 5 angstroms. PuriSorb HMS-05 can be applied for both liquid and gas dehydration. Such as natural gas, air, propane, LPG and other hydrocarbon dehydration. It can also be applied for removal of H2S, CO2 and light mercpatans from various streams. It is usually used for natural gas and LPG sweetening.
PuriSorb HSG-02 is a spherical bead silicate gel which is a porous, amorphous form of silica (SiO2). Although it has the same chemical composition as sand, silica gel is radically different from other SiO2-based materials due to its unique internal structure with quick adsorption and desorption. PuriSorb HSG-02 is mainly used for PSA, the recovery, separation and purifying of carbon dioxide gas, also can be used for preparation of carbon dioxide in synthetic ammonia industry, food & beverage processing industry, etc.
PuriSorb HAC-05 is a low ash activated carbon which manufactured by activating with steam from selected coals. PuriSorb HAC-05 is widely used for plants based on pressure swing adsorption and has proved its worth for decades with the extraordinary high performance like excellent adsorption capacity, high selectivity, long-term stability. PuriSorb HAC-05 is commonly used for hydrogen purification by PSA, hydrogen purification of various gases leaving steam reformer, catalytic reformer, or ethylene plants by means of PSA technology.
3. Process Flow
The PSA unit uses Pressure Swing Adsorption (PSA). Impurities are adsorbed at high pressure and then desorbed at low pressure.
Each adsorber goes through the same cycle of adsorption and regeneration without change in temperature, except for the heat of adsorption and desorption.
In the main mode of operation, there is always 1 adsorber in adsorption, while the others are in depressurisation, regeneration or repressurisation.
A. During adsorption, feed gas enters the bottom of the adsorber, while pure hydrogen leaves from the top. At the end of adsorption, the adsorber is loaded with impurities,concentrated at the bottom.
B. The remaining hydrogen concentrated at the top is first removed by co- current depressurisation and used to repressurise (equalise) and purge other adsorbers.
C. Subsequently, the adsorbers are counter-currently depressurised (from top to bottom) in the blowdown step.
D. Following the blowdown step the adsorbers are purged with the high purity stream provided in step B (providing purge). In steps C and D the gas leaving the adsorbers at the bottom is sent to an off-gas drum to obtain a steady and homogeneous off-gas flow.
E. Before going back into the adsorption step, the adsorber has to be repressurised with gas provided in step B (equalisation) and a slipstream of the product gas.
4. Production Specification
The main target product is hydrogen product with hydrogen purity over 99.9vol% and CO content (CO<10ppmv) and CO2 content (CO2 <10ppmv) meeting specification.
5. Reference
So far, the technology has been used on over 90 commercial units.
Pressure Swing Adsorption (PSA) is a critical purification technology for producing high-purity hydrogen efficiently and reliably. Its performance depends not only on the PSA process design, but also on the adsorption capacity, selectivity, mechanical strength, and stability of the adsorbents used in each adsorption bed.
At CHEMPACK, we recognize that PSA performance must be evaluated as part of the entire hydrogen production system. Proper adsorbent selection, operating-cycle optimization, and stable process control can help improve hydrogen recovery, maintain product purity, reduce adsorbent consumption, and extend operating cycles.
With more than 30 years of experience in adsorbent and catalyst technologies, CHEMPACK provides high-performance adsorption materials and technical solutions for hydrogen purification and other industrial gas-processing applications. By matching adsorbent properties with feed composition and operating conditions, we help customers achieve stable hydrogen purity, efficient recovery, and reliable long-term PSA operation.
