CO2 Removal from Syngas
Problem
In syngas production, CO2 is a desirable feed to the reformer (or gasifier) because it reduces methane consumption and produces a syngas with a more optimal H2:CO ratio. Often the added CO2 is imported from a nearby process. However, another attractive CO2 source is to recover and recycle CO2 from the reformer/gasifier discharge stream; a simple technology to recover this CO2 and recycle it to the reformer would be very attractive. Additionally, reformers and gasifiers used to produce hydrogen are significant producers of CO2, and recovery of this CO2 for sequestration will play an important role in reducing greenhouse gas emissions. Until recently, membranes could not be used in these applications because conventional CO2 removal membranes do not separate CO2 from hydrogen.
VaporSep® Solution
CO2 recovery and recycle using membranes
MTR’s unique Polaris™ membrane is a new development that allows membranes to separate CO2 from streams containing hydrogen. The Polaris membrane is much more permeable to CO2 than to H2, and can be used to recover a significant amount of the CO2 contained in the reformer/gasifier discharge for recycle to the reformer. When downstream processes require a higher degree of CO2 removal, a small conventional CO2 removal unit may be added. If CO2 sequestration rather than CO2 recycling is the goal, the concentrated CO2 discharged from the membrane can be liquefied and pumped to the sequestration site.
Benefits
Membranes being installed in a CO2 removal system
- Efficient CO2 recycle or removal: membrane systems can typically separate 80% of feed CO2.
- Simple reliable 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: cooling water, instrument air, instrument power, N2 (for purging)
- Proven performance: Polaris membranes have been widely tested in the lab and field. First commercial installation has been operating trouble free for more than 2 years.
- Long membrane life: the CO2 membrane is made from very robust materials, and is expected to have a lifetime of 4 to 5 years or more.
System Performance
- Feed pressure: up to 800 psi
- Feed: 1 to 200 MMscfd; 10 to 60 vol% CO2
- CO2 recovery: greater than 50 to 80+%
- Modular construction: 1 or 2 skids, each 30 ft (L) x 10 ft (W) x 12 ft (H)
Application Areas
- H2 plants
- Syngas production
- Methanol production
- Gasifiers feeding integrated gasification combined cycle (IGCC) gasifiers and other power plants
- Pressure swing adsorption (PSA) feed/tail gas