Copper Ore As Oxygen Carrier For Chemical Looping With Oxygen Uncoupling

Due to the using of large amounts of fossil fuels, such as coal, oil and natural gas, greenhouse effect has become increasingly serious, so does the CO2 emission reduction pressure. In China, the coal consumption amount is about 70% in the total energy consumption. Therefore, the research of CO2 Capture Utilization and Storage(CCUS) technology in coal combustin has important significance. Chemical Looping with Oxygen Uncoupling(CLOU) is a novel of Chemical Looping Combustion(CLC). The process uses a metal oxide as oxygen carrier(OC) which can release gesous oxygen at sutiable temperature(800~1200 oC) and cycle between fuel reactor and air reactor. It avodes the directly contect of fuel and air, and can capture very pure CO2 with low cost and achieve the clean and effective utilization of coal. In this work, a copper ore with low cost was used as OC. The CLOU reactiviety of copper ore with different coals and sulfur behavior in the CLOU process were researched.The copper ore used in this work is mainly consisit of CuO and CuFe2O4, and has a copper content of 44%. Firstly, the performance of the CLOU process for three typical coals was investigated in a batch fluidized-bed reactor. It was found that an increase in the temperature and a decrease in the coal rank both had a beneficial effect on the reaction rate of coal. It was also found that the rate-limiting step in CLOU of anthracite was the reaction between gaseous oxygen and coal char and the copper ore particles was easily to occur agglomeration and sintering with lignite at high temperatures. In addition, introducing the gasification agents(steam or CO2) into the fuel-reactor can increase the instantaneous rate of char conversion of high-rank coal.Secondly, experiments of a H2S-containing synthesis gas as fuel with this copper ore as OC were performed by thermogravimetric analysis and Fourier transform infrared(TGA–FTIR) spectroscopy and a batch fluidized-bed reactor. The sulfidation of the copper ore with H2 S was observed. The main sulfide products for copper ore were Cu2 S and FeS, and the reactivity of copper oxides reacting with H2 S was higher than that of iron oxides. The FITR results showed that SO2, COS, and CS2 were the main gaseous sulfur species observed during the reduction and only SO2 during the oxidation. The simulation results from the HSC Chemistry software agreed well with the results obtained in TGA-FTIR experiments. The fluidized-bed experiment results showed that the sulfidation of copper ore degraded oxygen transport capicity and reactivity of the oxygen carrier.Finally, the performance of copepr ore with high S coal was investigated in the batch fluidized-bed reactor. The sulfur behavior in CLOU process and effects on copper ore were analyzed. It was found that the mian gaseous sulfur species in reduction was SO2, and small amount of H2 S was also found. However, in oxidation process, no gaseous sulfur species was found, indicating that no sulfide products was produced in the reduction process. The cycle test showed that the reaction rate for copper ore with high S coal was decreased slightly with the cycle number. When adding the desulfurizer CaO into reactor, the absorptivity of gaseous sulfur species reached 98%. Furthermore, The simulation results from the HSC Chemistry software agreed well with the results obtained in fluidized-bed experiments.