Power

IGCC Efficiency / Performance

Consideration of efficiency and relative performance of current technology-based IGCC cycles has been made by NETL in ongoing studies.1 These include IGCC power plants based upon a few major gasification technologies, as depicted in Figure 1.



Figure 1: IGCC Power Plant without CO2 Capture
Figure 1. (click to enlarge)

On these bases, estimated net efficiencies for near-term high efficiency ~625 MW-size (non-CC) integrated gasification combined cycle (IGCC) power plants, designed for Illinois No. 6 coal feed, without carbon dioxide (CO2) capture, range from:1

  • 39.0% (HHV) for the GEE radiant-only plus quench gasification-based IGCC;
  • 39.7% (HHV) for the CoP E-Gas™ two-stage gasification-based IGCC;
  • 42.1% (HHV) for the Shell dry-feed gasification-based IGCC.

These illustrate the relative IGCC efficiency advantage among the three gasification technologies. Because the dry-feed technology eliminates the need to vaporize water in the gasifier, the Shell-based IGCC is more efficient than the two slurry-feed GE and Conoco Philips (CoP)-based IGCC. Considering the slurry-feed GE and CoP-based IGCC cycles, the 2-stage CoP E-Gas™ technology is more efficient because of its lower operating temperature, as measured by the gasifier syngas exit temperature.

IGCC plants corresponding to the foregoing, but including carbon capture, are as depicted in Figure 2.



Figure 1: IGCC Power Plant with CO2 Capture
Figure 2. (click to enlarge)

Corresponding cycle efficiencies are as follows:

  • 32.6% (HHV) for the GE radiant-only plus quench gasification-based IGCC with carbon capture;
  • 31.0% (HHV) for the CoP E-Gas™ two-stage gasification-based IGCC with carbon capture;
  • 32.2% (HHV) for the Shell dry-feed gasification-based IGCC;

In the carbon capture cases, the relative efficiencies observed in the non-capture cases are both lowered and skewed by the significant energy penalty associated with process modifications for 90% carbon capture. These accrue from loss of gross power generation because of increased amount of steam diverted for use in the Selexol process, rise in ASU air compression load without combustion turbine integration, and increases in auxiliary power for the gas cleanup/CO2 capture. Taken together, the energy penalties happen to be least for the GEE-based cycle and most for the Shell cycle. Overall, with carbon capture included, this causes overall efficiencies to be more nearly equal among the three gasifier type cycles.

Table 3 summarizes the main performance parameters for all the above, in terms of power, heat rate, and efficiencies.

IGCC Performance Results
Table 3: IGCC Performance Results (click to enlarge)
1CO2 Capture Energy Penalty = Percent points decrease in net power plant efficiency due to CO2 Capture.

Table 4 summarizes the economic results for the various IGCC cases, including plant capital costs, cost of electricity, and cost of avoided CO2.

IGCC Economic Results
Table 4: IGCC Economic Results (click to enlarge)
1Total Plant Capital Cost (Includes contingencies and engineering fees but not owner's costs)
280% Capacity Factor

 


1. 2010 DOE/NETL "Cost and Performance Baseline for Fossil Energy Plants", Vol. 1


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