TECHNOLOGIES FOR HYDROGEN PRODUCTION

Hydrogen Production from Coal without Power Export

In cases where the goal is to produce hydrogen (H2) from coal without power export, the overall flow arrangement can be further simplified. Figure 3 is a block flow diagram for producing H2 from coal with minimal power generation. Onsite power generation is kept to a level to meet internal consumption, and if necessary, some power can also be imported. Key differences from H2 co-production in integrated gasification combined cycle (IGCC) with carbon sequestration (Figure 1) are:

  • Eliminating the need for H2 fired gas turbine (GT) by switching to low or medium Btu fuel-fired boiler plant.
  • Changing the pressure swing absorption (PSA) purge compressor to a lower head blower.
  • Eliminating the need to compress air separation unit (ASU) waste nitrogen (N2) for use as diluent.
 
CLICK ON GRAPHIC TO ENLARGE
Coal-Based Hydrogen Production (Without Power Export) Block Flow Diagram 
Figure 1: Coal-Based Hydrogen Production (Without Power Export) Block Flow Diagram

Table 1 lists some of the published overall performance and efficiency values for coal-to-H2 production only design studies that correspond to this process arrangement. Results are shown for variations with and without carbon dioxide (CO2) capture scenarios, and are for minimal power co-production without the use of gas turbines.

Table 1: Hydrogen Production Only Plant Performance & Efficiency 1,2
Co-Production 
Minimal
Minimal
Minimal 
Minimal
CO2 Capture 
No
No
No
Yes
Gasifier Type
E-Gas™
GE
Coal Feed: 
      Type 
      Coal Feed, STPD

Pitt # 8
2,660

Wyodak
3,406

ILL # 6
3,000

ILL # 6
3,000
Products:
      Hydrogen, MMSCFD 
      Export Power, MW

118
37.6

98
41.8

131
20.4

119
26.9
Overall Efficiency, % HHV
62.3
59.7 
63.7
59

References/Further Reading

1. Polygeneration of SNG, Hydrogen, Power, and Carbon Dioxide from Texas Lignite (Dec 2004)
D. Gray, S. Salerno, G. Tomlinson & J. J. Marano, Mitretek Technical Report for NETL
2. Capital and Operating Cost of Hydrogen Production from Coal Gasification (Apr 2003)
Final Report by Parsons for NETL

Hydrogen

 
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