Conceptual design of a 100MWth CLC unit for solid fuel combustion

• Published in: Applied energy Vol. 157; pp. 462 - 474
• Main Authors: Abad, Alberto, Adánez, Juan, Gayán, Pilar, de Diego, Luis F., García-Labiano, Francisco, Sprachmann, Gerald
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.11.2015
• Subjects: Chemical looping combustion; CO2 capture; Coal; Design; iG-CLC; Modelling; Design; iG-CLC; Coal; Modelling; CO2 capture; Chemical looping combustion
• ISSN: 0306-2619; 1872-9118
• DOI: 10.1016/j.apenergy.2015.04.043

Design layout of the 100MWthiG-CLC system. [Display omitted] •The basic design of a 100MWthiG-CLC unit for coal combustion has been carried out.•A template is introduced to easily carry out the design of fuel and air reactors.•Fluid dynamic and cyclone sizes affecting the design of the complete CLC loop were included.•CO2 in the fuel reactor, instead of H2O, was preferred in iG-CLC and energy penalty was minimized.•For a sub-bituminous coal, 7% of oxygen demand and 95% CO2 capture was predicted. The conceptual design of a 100MWth unit for coal combustion with CO2 capture by in-situ Gasification Chemical Looping Combustion (iG-CLC) was done. Ilmenite was considered the oxygen carrier and a highly reactive sub-bituminous coal was the fuel. The main components of the iG-CLC unit were a fuel reactor, a carbon stripper and an air reactor. Mass and enthalpy balances were performed to determine the solids circulation flow rate, temperature of the reactors, steam and air requirements, and heat duty of heat exchangers. Fluid dynamics considerations and cyclones sizes were taken into account for the conceptual design and the dimensioning of these devices. In addition, optimized operating conditions obtained with a mathematical model were considered in the design procedure. Then, the performance of the iG-CLC unit was estimated with the model. Some benefits were identified when recirculated CO2 was used to fluidize the carbon stripper and fuel reactor, regarding both fuel reactor performance and energy integration of the iG-CLC system. Thus, a CO2 capture value of 95% with a carbon stripper with 98% efficiency and an oxygen demand in exit gases from the fuel reactor of 7% was predicted with a solids inventory in the fuel reactor of 750kg/MWth. Moreover, the energy penalty related to steam generation was minimized when H2O was replaced by CO2. Results presented in this work can be used to estimate the net efficiency of the plant in future works.