CO2 capture from advanced steel production processes
Publieke samenvatting / Public summary
TATA Steel is developing an advanced steelmaking process to replace blast furnace technology. The HIsarna pilot plant at TATA Steel in IJmuiden uses ground-breaking technology to produce liquid iron. By combining HIsarna with CCS technology, it can reduce CO2 emissions of up to 80%.
At the time of this project, the HIsarna pilot plant produced a maximum of 19.7 ton/h CO2 and represented an excellent opportunity to demonstrate CO2 purification for geological storage. A CPU pilot plant could therefore help to develop a positive business case. Moreover, the operation of the pilot plant was a necessary de-risking step towards the demonstration of HIsarna.
The project investigated the options to integrate the advanced HIsarna process with state-of-the-art CO2 purification technologies for a demonstration plant sequestrating 1.7 Mt CO2/year of different grades, and a pilot plant producing 54 kt/year of food-grade CO2. TNO proposed and investigated four technology scenarios by performing a techno-economic evaluation of the integrated concept for a demonstration plant sequestrating 1.7 Mt CO2/year, and a scenario for the pilot plant, producing 54 kt/year of food-grade CO2. The report describes the scenarios evaluated and the results obtained for each scenario.
The project evaluated four scenarios for the CPU of the demo HIsarna plant, and a pilot CPU was also designed. The scenarios aimed to deliver different CO2 qualities, so conceptual designs of different CPU technologies were performed. The lowest CO2 cost was obtained in scenario 1 (9 to 11 €/ton), in which 100% of the CO2 was recovered, with a purity of ca. 93%. The gas met the specifications for injection in a saline aquifer. In scenario 2, a technology using two separation flash vessels was simulated. This led to a similar cost to that of scenario 1 (10 to 12 €/ton) in the case of the RED gas. However, the cost under the OXI case was much higher due to the use of hydrogen to remove oxygen deeply. It was concluded that, if the CO2 product was intended for EOR purposes, the HIsarna plant should be operated in the reduction mode. The technology simulated in scenario 3, Flash+Distillation, resulted in the highest CO2 costs (from 15 to 22 €/ton). In comparison, the technology proposed in scenario 4, which used an external refrigeration cycle to liquefy CO2, led to a higher-purity product with lower associated cost.
One important knowledge gap identified in the study was the lack of a model to accurately estimate the NOx and SOx content in the final CO2 product. The simulations indicated that the NOx content in the CO2 product for S1 and S2 should be around 10 ppm, and the SOx content negligible. The report argues that the relatively high limit in saline aquifer and EOR specifications means the NOx and SOx removal in the CPU was likely to be enough for those scenarios.