Investigation of Air Extraction and Carbon Capture in an Integrated Gasification Combined Cycle (IGCC) System

2021 ◽  
Author(s):  
Shisir Acharya ◽  
Ting Wang

Abstract Coal is one of the major sources of energy currently as it provides up to 38.5% of the total electricity produced in the world. Burning coal produces pollutants and large amounts of CO2, which contribute to climate change, environmental pollution, and health hazards. Therefore, it is our obligation to utilize coal in a cleaner way. Cleaner coal energy can be produced by using an ultra-supercritical Pulverized Coal (PC) power plant, or by employing the Integrated Gasification Combined Cycle (IGCC). Since the 1970s, the IGCC technology has been developed and demonstrated, but it has still not been widely commercialized. One of the methods to improve IGCC performance is to save the compression power of the air separation unit (ASU) by extracting the compressed air from the exit of the gas turbine as a portion of or the entire air input to the ASU. This paper investigates the effect of various levels of air integration on the IGCC performance. The results show that a moderate air integration ranging from 15% to 20% provides the most effective air-integration. An analysis of implementing a sour-shift pre-combustion carbon capture results in a significant loss of about 5.5 points in efficiency. This study also provides the effect of air integration and carbon capture on emissions including NOx, SOx, CO2, and water consumption.

Author(s):  
Prashant S. Parulekar

The gasifier in an Integrated Gasification Combined Cycle (IGCC) Power Plant gasifies coal using an oxidant gas that facilitates partial combustion and effective gasification of the coal feed. When electricity generation is the prime objective of the IGCC facility this oxidant can be ambient air, or gaseous oxygen produced from an Air Separation Unit (ASU). Gasification technology providers are presently divided in their type of offering and information in the public domain does not effectively guide End Users in the advantages and disadvantages of the two gasification methods as applicable to the particular project being developed. This paper highlights key design aspects that should guide End Users in making an effective assessment and perform detailed evaluation of the gasification technologies for the particular IGCC project in consideration.


Author(s):  
S. Ravelli ◽  
A. Perdichizzi

In this paper a simulation tool (Thermoflex®) has been setup to model an entire Integrated Gasification Combined Cycle (IGCC) on the basis of the report entitled “Cost and Performance of PC and IGCC Plants for a Range of Carbon dioxide Capture” by DOE/NETL [1]. The investigated layout has no water-gas-shift (WGS) reactor and does not allow for any CO2 capture. Two gasification islands are included, each of which consists of Air Separation Unit (ASU), GEE radiant-only gasifier, quench and syngas scrubber as well as syngas cleanup. Two advanced GE’s F-class gas turbines (2 × 232 MW), coupled with two heat recovery steam generators and one steam turbine (276 MW) constitute the power block. In the IGCC simulation, the base model of the GE 7F.05 gas turbine has been adapted to burn syngas. Mass and energy balances were carefully computed on design condition to validate the proposed modelling procedure against the IGCC performance data contained in the above mentioned report: the net power output of 622 MW was underestimated by about 5% whereas the net electric efficiency was slightly overpredicted. The off-design behavior of the syngas turbine was then simulated as dependent on ambient temperature and partial load, in preparation for modelling flexible operation of the whole power plant. The variation in IGCC net efficiency and power output was assessed in a load following operational strategy, thus reducing the load factor and varying the number and slope of ramps in a typical day. The IGCC net efficiency goes down from 42.5% to 32.8% when the load is reduced from 100% to 40% of the design rate.


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