7.3.2. Co-producing H2 in IGCC with Carbon Sequestration

Figure 1 is a block flow diagram for co-producing H₂ in a future integrated gasification combined cycle (IGCC) plant with carbon sequestration. Key differences from hydrogen (H₂) co-production in today's IGCC, in addition to developing new gas turbines capable of firing fuel with very high H₂ content, are:

• Use of a full quench gasifier without a high temperature gas cooling (HTGC) system to maximize moisture in syngas feed to the sour shift system for maximum conversion of carbon monoxide (CO) to H₂.
• Selective removal of all of the CO₂ from the sour syngas with a two-stage AGR to produce a separate carbon dioxide (CO₂) product stream to be dried and compressed for sequestration.
• Routing all of the sweet gas from AGR (mainly H₂ with small amount of nitrogen (N₂), methane, and unconverted CO) through pressure swing absorption (PSA) to recover 99.9% H₂ product.
• Bypassing the required amount of H₂ product to be combined with the compressed PSA purge to meet the gas turbine (GT) fuel requirement.
• Compression of some of the waste N₂ from the air separation unit (ASU) for use as diluent in the GT to offset mass loss from CO₂ removal.

Table 1 lists typical coal-to-H₂ plant performance and efficiency parameters for this type of process scheme. There are three different variations, using different coal feed and gasifiers. The performance and efficiency shown include CO₂ compression for sequestration, and are for maximum power co-production with the use of gas turbine.

Hydrogen

• Why Hydrogen
• Hydrogen & Synthetic Natural Gas from Coal
• Technologies for Hydrogen Production
  • Co-producing H₂ with Current IGCC Technology
  • Co-producing H₂ in IGCC with Carbon Sequestration
  • Hydrogen Production from Coal without Power Export
  • IGCC/H₂ Co-production with WGCU and Advanced WGS Membrane
• Technology for SNG Production
• SNG from Coal: Process & Commercialization
• DOE Supported R&D for Production of Hydrogen