Hydrogen Separations in Syngas Processes
Syngas Ratio Adjustment
Syngas (H2 + CO) is required to make a variety of products. Each of these syngas derivatives has a specific ratio of H2 to CO in the feed syngas that is optimal for its production. However, the H2:CO ratio produced is a function of the syngas process and the hydrocarbon feed. This ratio will not necessarily be optimal for downstream products. Therefore, some method for reducing the amount of hydrogen in the syngas is needed.
Membrane Solution
Syngas ratio adjustment using membranes
VaporSep®-H2 offers a simple method for separating H2 from syngas to adjust the H2:CO ratio. In a typical system, the feed gas is first cooled to remove condensable hydrocarbons, and then heated before entering the membrane. Hydrogen preferentially permeates through the membrane, producing a purified hydrogen “permeate” stream and a hydrogen-depleted “ratio-adjusted syngas” stream. This ratio adjustment may even produce high-purity CO for processes requiring it as a feed.
Hydrogen Recovery From Synthesis Loop Purge Streams
When syngas is used to produce chemicals such as methanol and ammonia, the synthesis loop must be purged continuously to avoid buildup of inert gases such as argon and methane. These purge streams are mainly syngas – if the hydrogen in the purge stream can be purified, it has significant value for recycle to the process or for reuse in a nearby refinery or chemical plant.
Membrane Solution
Purge gas hydrogen recovery using membranes
VaporSep-H2 offers a simple method for separating H2 from synthesis purge streams. In a typical system, the feed gas is first cooled to remove condensable hydrocarbons, and then heated before entering the membrane. Hydrogen preferentially permeates through the membrane, producing a purified hydrogen “permeate” stream and a stream of concentrated inerts. The purified hydrogen is recompressed and recycled to the synthesis loop.
Benefits
Unit for hydrogen removal
- Efficient syngas and hydrogen recovery: membrane systems typically recover 90% to 98% of feed CO and produce a hydrogen product at 85 to 95 vol% purity.
- Proven performance: 5 references for H2/CO adjustment, including pressures as high as 130 bar and operating lifetimes of more than 10 years.
- Long membrane life: typical membrane lifetime is 10 years or more.
- Simple, reliable, and flexible unit; easy to install and operate:
- Integrates into existing operations with minimal modification
- Simple installation and operation with compact skid-mounted construction
- Requires no chemicals, contains no moving parts
- Minimal utility usage: low pressure steam, instrument air, instrument power, N2
System Performance
- Feed pressure: up to 2500 psi
- Feed: 1 to 100 MMscfd; 35 to 65 vol% H2
- Recovered H2 purity: 85 to 95 vol%
- Modular construction: 1 or 2 skids, each 20 ft (L) x 8 ft (W) x 18 ft (H)
Application Areas
- H2 purification
- CO purification
- Syngas ratio adjustment for the following:
- Methanol, oxo alcohols
- Gas-to-liquids (GTL), power turbine