Thermodynamic analysis of in situ gasification-chemical looping combustion (iG-CLC) of Indian coal

Abstract

Chemical looping combustion (CLC) is an inherent CO capture technology. It is gaining much interest in recent years mainly because of its potential in addressing climate change problems associated with CO emissions from power plants. A typical chemical looping combustion unit consists of two reactors-fuel reactor, where oxidation of fuel occurs with the help of oxygen available in the form of metal oxides and, air reactor, where the reduced metal oxides are regenerated by the inflow of air. These oxides are then sent back to the fuel reactor and the cycle continues. The product gas from the fuel reactor contains a concentrated stream of CO which can be readily stored in various forms or used for any other applications. This unique feature of inherent CO capture makes the technology more promising to combat the global climate changes. Various types of CLC units have been discussed in literature depending on the type of fuel burnt. For solid fuel combustion three main varieties of CLC units exist namely: syngas CLC, in situ gasification-CLC (iG-CLC) and chemical looping with oxygen uncoupling (CLOU). In this paper, theoretical studies on the iG-CLC unit burning Indian coal are presented. Gibbs free energy minimization technique is employed to determine the composition of flue gas and oxygen carrier of an iG-CLC unit using FeO, CuO, and mixed carrier-FeO and CuO as oxygen carriers. The effect of temperature, suitability of oxygen carriers, and oxygen carrier circulation rate on the performance of a CLC unit for Indian coal are studied and presented. These results are analyzed in order to foresee the operating conditions at which economic and smooth operation of the unit is expected.

Characteristic Evaluation and Process Simulation of CuFe2O4 as Oxygen Carriers in Coal Chemical Looping Gasification

“…Nowadays, the utilization of fossil fuels has been considered as one of the biggest problems to the increasing emission of CO 2 . Chemical looping has emerged as a promising technology for coal utilization as it decreases the irreversible entropy production to increase the energy utilization efficiency. , It takes advantage of the redox behavior of oxygen carriers (OCs) between two individual reactors to realize initial CO 2 separation and NO x emission control without the enrollment of pure oxygen. − In situ gasification chemical looping combustion (CLC) is known as a typical strategy for coal utilization for complete oxidization between the fuel and the OC in the reducer. , Conversely, chemical looping gasification (CLG) − was proposed to achieve plenty of syngas (H 2 and CO) through partial oxidization, as is shown in Figure .…”