Techno-economic evaluation of electronic waste based oxygen carriers for co-chemical looping combustion of coal and biomass integrated combined cycle power generating systems

Abstract

Chemical looping combustion (CLC) is an emerging technology to capture CO2 in a cost-effective way. Metal particles such as Fe, Ni, and Cu can separate oxygen from air by forming their oxides and they could thereby act as oxygen carriers for the combustion of fuels producing nitrogen-free CO2 enriched flue gas. To commercialize the CLC based carbon capture technology, low cost oxygen carriers are essential for economical operation. Electronic waste contains enormous metal components, which can be a potential source for the production of oxygen carriers. In the present study, mixed oxygen carrier particles obtained from a printed circuit board (PCB) based electronic wastes are proposed to use in the CLC process. A combustion experiment is conducted to extract metals from the PCB and their composition is identified using an XRF analyzer. These metals are found with 21% Fe2O3, 22.8% CuO and 3% NiO, 9.6% CaO and 10% Al2O3. Using these oxidized printed circuit board metals (OPCB) as oxygen carriers, Aspen plus simulations are performed by integrating a CLC system with a combined cycle power plant having a net capacity of 150 MW for electricity generation. High ash coal (33% ash) and low ash coal (2.1% ash) and rice straw are used in a co-combustion mode for the CLC operation. The effect of co-firing on the net thermal efficiency of the power plants is analyzed. Further economic analyses are carried out for the proposed system and the levelized cost of electricity (LCOE) is estimated for the power plants using various fuels. It is found that the use of electronic waste based oxygen carriers achieved almost an equivalent net thermal efficiency of 42.4% based on the combined cycle power plants, compared to pure Fe2O3 based power plants. Further the economic analysis has shown that the levelized cost of electricity (LCOE) of the CLC integrated combined cycle power system employed with electronic waste based oxygen carriers is 85.9 $/MWh, which is the lowest among other power systems. Metal oxide interaction with fuel ash is investigated experimentally using a thermogravimetric analyzer (TGA). The X-ray diffraction (XRD) analyses of the residue confirmed that there is no formation of complex components due to the ash interaction with OPCB.