Sekisui Chemical has been developing technologies to efficiently convert CO₂ to CO with Reverse Water Gas Shift (RWGS) reaction by Chemical Looping(CL).
Among the various CO₂ utilization approaches, the RWGS reaction plays a pivotal role, since it produces synthesis gas (syngas or CO + H₂), the building block of numerous conversion processes. Average CO generation yields are 40~60%¹ with conventional RWGS. Introduction of metal oxide as an Oxygen Storage Material (OSM) would bring the RWGS reaction further by splitting the reaction itself into a reduction and oxidation reaction, referred to as a RWGS-CL, an intensified version of the conventional RWGS. By switching the gas flow between at least two reactors after the OSM is reduced or oxidised, respectively, a quasi-continuous process can be achieved, which is more efficient compared to the classical RWGS as it yields partially separated gas streams, simplifying the downstream gas separation. The CL technology developed by Sekisui has validated >90% CO yield and 80% H₂ conversion at demonstration with blast furnace gas in Spain², due to the non-equilibrium nature of the looping process, which can be employed to achieve high yield. This achievement is a result of NEDO's international joint research and development project (JPNP20005) in the field of clean energy.
In Japan, Sekisui Chemical has started a demonstration project to produce high-performance chemicals by combining this CO₂ to CO technology with the downstream bio-process from waste incineration plants, and plans to start a sales business of these high-performance chemicals produced from CO₂ derived from wastes in 2030³. In addition, Sekisui has started collaboration with Tokai Carbon in Japan for the purpose of manufacturing CO₂-derived carbon products using this CO₂ to CO technology⁴.
By applying the CO₂ to CO technology to CO₂-containing waste gas in steelmaking process, Sekisui hopes to contribute to CCU and decarbonization in steel plants.