Hydrogen recovery and purification or rejection from various refining, petrochemical and chemical process gas streams. Other examples are: synthesis gas ratio adjustment and carbon monoxide (CO) recovery.
Feed: Refinery streams include: catalytic reformer offgas, hydrotreater and hydrocracker purge and
fluid catalytic cracking offgas. Chemical and petrochemical feed streams are: ethylene offgases, ammonia plant purges, methanol plant offgases, synthesis
gas streams from steam reforming, partial oxidation
or other gasification technologies.
Product: For typical hydrogen purification applications, recovery varies between 70% and 95+% and purity ranges from 70 to 99 mole%, depending on feed composition, pressure levels and product requirements. Polysep membrane systems are also designed to produce high-purity CO for petrochemical products such as polyurethanes and polycarbonates, and to ratio adjust synthesis gas streams in methanol and oxoalcohol plants. Also, a new application is hydrogen recovery from IGCC power generation systems.
The Polysep separation system is based on state-of-the-art, composite, hollow-fiber polymer membrane technology. The hollow fibers are packaged in a proprietary countercurrent-flow bundle configuration that maximizes the separation driving force and minimizes required membrane area.
The Polysep separation is a pressure-driven process. It requires a minimum of moving parts, utilities and operator attention. The systems are compact, shop-fabricated, modular units allowing reduced delivery schedules and simple inexpensive installation. Feed pretreatment equipment typically includes: a knockout drum for bulk liquid removal, a coalescing filter for particulate and entrained liquid removal, and a preheater to optimize the membranes’ performance.
Operation features include: automatic startup, capacity control, product-purity control, auto depressurization and turnup/turndown. Turndown capability is typically 30% using a patented control strategy. Membrane system control is typically via integration into the refinery’s control system. Once installed, a membrane system can reach steadystate operation from cold startup in a few hours with onstream factors over 99.8% relative to unplanned shutdowns.
Economics: Polysep membrane systems can be efficiently and economically scaled, from just a few modules
to over 100 modules, depending on the application. Membrane-separation systems have low capital costs and plot area, and offer a rapid return on investment.
Licensor: UOP LLC