Combined Calcium Looping and Chemical Looping Combustion for Post‐Combustion Carbon Dioxide Capture: Process Simulation and Sensitivity Analysis

Abstract

In this work, a combined calcium looping and chemical looping combustion (CaL–CLC) technology is simulated at thermodynamic equilibrium conditions and the results in terms of efficiency, power production, and solids circulation rates are compared with the case of using CaL alone. In addition, a new solids looping configuration in the CaL–CLC process is proposed with the purpose of mitigating the loss of calcium oxide conversion after high cycle numbers. Simulations show an improved process efficiency of the CaL–CLC method compared with CaL alone (34.2 vs. 31.2 % higher heat value) and an increased power output (136 vs. 110 MWe additional power) due to the higher energy requirement to preheat the reactants. A sensitivity analysis of the process operating parameters highlights the particular importance of the temperature difference between reactors, which has a strong impact on the required mass of solids circulating in the loops. Finally, partial carbon dioxide capture scenarios are considered and indicate that lower capture levels are suitable to match regulation targets.

Simulation of a calcium looping CO2 capture process for pressurized fluidized bed combustion

“…Estimations for the energy penalty of CaL on the base power plant are also provided as an additional comparison criterion. In this investigation, the gross efficiency associated with power production from the carbon capture process is based on previous work on a similar system . The capture process simulations are based on the cyclic CO 2 sorption of a limestone that was investigated in a series of thermogravimetric analyzer (TGA) experiments.…”

“…In this investigation, the gross efficiency associated with power production from the carbon capture process is based on previous work on a similar system. [9] The capture process simulations are based on the cyclic CO 2 sorption of a limestone that was investigated in a series of thermogravimetric analyzer (TGA) experiments. The limestone was subjected to multiple cycles of relatively high-temperature carbonation and lowtemperature calcination.…”

Calcium looping combustion for high-efficiency low-emission power generation

“…The main alternative heat sources to drive the calcination process include chemical looping [19][20][21][22], which uses oxygen carriers to transfer oxygen from air to the fuel, and indirect heat transfer from a combustor via solid heat carriers [15,23], heat transfer wall [15,24] or heat pipes [25,26]. The combined calcium and chemical looping system includes an additional reactoran air reactorin which the oxygen carrier reacts with oxygen in the air, forming a metal oxide.…”

“…This system can operate as either a single-or dual-loop process [20,22], depending on whether the oxygen carrier is mixed with the sorbent and reduced directly in the calciner, or is handled separately in another loop. In the latter case, the heat is transferred to the calciner indirectly.…”

High-efficiency negative-carbon emission power generation from integrated solid-oxide fuel cell and calciner

“…This introduces the main source of the parasitic load in the process, as O2 production is usually conducted in a cryogenic air separation unit that is characterised with a specific power requirement of 184-230 kWelh/tO2 [22][23][24]. The main alternative options to drive the calcination process include chemical looping [25][26][27][28], which uses oxygen carriers to transfer oxygen from air to the fuel, and indirect heat transfer from a combustor via solid heat carriers [29,30], heat transfer wall [30,31] or heat pipes [32,33].…”