A review of the technologies for coal-based power generation closest to commercial application involving carbon capture is presented. Carbon capture and storage (CCS) developments are primarily adaptations of conventional combustion systems, with additional unit operations such as bulk oxygen supply, CO2 capture by sorbents, CO2 compression, and storage. They use pulverized coal combustion in entrained flow—the dominant current technology for coal-based power, or gasification in entrained flow, although similar concepts apply to other solid–gas contacting systems such as fluidized beds. Currently, the technologies have similar generation efficiencies and are associated with efficiency penalties and electricity cost increases due to operations required for carbon capture. The R&D challenges identified for the combustion scientist and engineer, with current understanding being detailed, are those of design, optimisation and operational aspects of new combustion and gasification plant, controlling the gas quality required by CCS related units and associated emission compliance, and gas separations. Fundamental research needs include fuel reactions at pressure, and in O2/CO2 atmospheres, as few studies have been made in this area. Laboratory results interpreted and then included in CFD models of combustion operations are necessary. Also identified, but not detailed, are combustion issues in gas turbines for IGCC and IGCC-CCS. Fundamental studies should be a component of pilot-plant and demonstrations at practical scale being planned. Concepts for new designs of combustion equipment are also necessary for the next generation of technologies. The challenges involved with the design and operation of these integrated systems, while supplying electricity on demand, are considerable.

Combustion processes for carbon capture

Proposal of a semi-empirical kinetic model to reconcile with gasification reactivity profiles of biomass chars

In this paper, we describe the construction, validation, and application of a multiscale model of entrained flow gasification. Part I of the paper focused on the validation of the turbulence and particle turbulent dispersion submodels. In part II, the impact of suggested improvements in these submodels on the predictions of key output parameters is analyzed through appropriate sensitivity analyses. In addition, adaption of the moving flame front (MFF) model of char consumption to gasification computational fluid dynamics (CFD) and its impact on the overall predictions is presented. The accuracy of the integrated gasifier model is demonstrated by comparing its predictions with experimental data from pilot and research-scale Mitsubishi Heavy Industries (MHI) gasifiers and a laboratory scale gasifier from Brigham Young University (BYU). Finally, a practical limit on mesh refinement for RANS simulations of two-phase reacting flows, governed by solution stability, is discussed.

Multiphysics Simulations of Entrained Flow Gasification. Part II: Constructing and Validating the Overall Model

Simulation of entrained flow gasification with advanced coal conversion submodels. Part 1: Pyrolysis

Kinetics of pyrolysis and combustion of oil shale sample from thermogravimetric data

Numerical study on the coal gasification characteristics in an entrained flow coal gasifier

Experimental Studies of a 1 Ton/Day coal slurry feed type oxygen blown, entrained flow gasifier have been performed with the slurry concentration and gasifier temperature at 65% and above 1,300 ‡C, respectively. The characteristics of ash fusion temperature with addition of CaO as a flux were investigated to maintain the proper slag tapping condition in the range of reaction temperature. As the flux addition increased, ash fusion temperature showed a eutectic effect with the eutectic at around 20–30% CaO. In order to analyze the gasification characteristics, the effects of O2/coal feed ratio on the product gas composition, heating value, gasifier temperature and cold gas efficiency were evaluated. From the results, it was shown in the case of Kideco coal that the cold gas efficiency was 44–60% and the heating value was 1,700-2,200 kcal/Nm3, while Drayton coal showed a cold gas efficiency of 55–62% and a heating value of 1,800-2,200 kcal/Nm3. In the case of Datong coal, the cold gas efficiency was 38–65%, and the heating value was 2,000-2,300 kcal/Nm3. Also, the results showed that the optimal operating condition of O2/coal ratio for the three different coals was 0.9.

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Tae-Jun Park

Papers

Numerical study on the coal gasification characteristics in an entrained flow coal gasifier

Experimental Studies of 1 Ton/Day Coal Slurry Feed Type Oxygen Blown, Entrained Flow Gasifier

Wet coal gasifier

Method and apparatus for measuring high temperature reaction of coal