| Popis: |
A new combined chemical looping process makes use of any gas stream containing CO2 and fuel to produce carbon monoxide without external energy input. Carbon monoxide can be used for producing a variety of carbon-based products. The iron and steel industry is a carbon-intensive industry and one of the largest industrial sources of CO2 emissions. In this work, we show how the steel mill gases can be conditioned using three metal oxides to produce a CO/CO2 stream that can be used for the production of chemicals, thereby preventing the emission of carbon to the atmosphere as CO2. Abundant oxides of iron and manganese, characterised by their readiness to capture and release gaseous O2, and calcium oxide, characterised by its capacity to capture and release gaseous CO2 can be deployed in this process. Process analysis indicates that by fully utilising the chemical energy of the carbon-rich blast furnace gas (BFG) of the steel mill, 37% of the associated CO2 emissions can be eliminated. A techno-economic evaluation shows that further reduction of CO2 emissions is viable. Preliminary estimations indicate that the cost for processing BFG through the proposed process is 46 EUR2020 per tonneBFG. The sources of revenue are the product CO/CO2 stream (0.2 tonneproduct per tonneBFG) and electricity constituting 85% and 14% of the total revenue with the remaining 1% obtained by the sale of spent metal oxides used in the process. The technical feasibility of the process was experimentally proven in a fixed bed reactor to produce a CO/CO2 stream and an H2O-rich stream while the metal oxides were periodically regenerated in alternating redox conditions. Thirty executed cycles indicated stable performance of the process. The proposed process concept can be applied to any gas stream containing CO2 and fuel. |
