Evaluation of biomass-based production of below zero emission reducing gas for the iron and steel industry

Abstract

The present paper focuses on the production of a below zero emission reducing gas for use in raw iron production. The biomass-based concept of sorption-enhanced reforming combined with oxyfuel combustion constitutes an additional opportunity for selective separation of CO2. First experimental results from the test plant at TU Wien (100 kW) have been implemented. Based on these results, it could be demonstrated that the biomass-based product gas fulfills all requirements for the use in direct reduction plants and a concept for the commercial-scale use was developed. Additionally, the profitability of the below zero emission reducing gas concept within a techno-economic assessment is investigated. The results of the techno-economic assessment show that the production of biomass-based reducing gas can compete with the conventional natural gas route, if the required oxygen is delivered by an existing air separation unit and the utilization of the separated CO2 is possible. The production costs of the biomass-based reducing gas are in the range of natural gas-based reducing gas and twice as high as the production of fossil coke in a coke oven plant. The CO2 footprint of a direct reduction plant fed with biomass-based reducing gas is more than 80% lower compared with the conventional blast furnace route and could be even more if carbon capture and utilization is applied. Therefore, the biomass-based production of reducing gas could definitely make a reasonable contribution to a reduction of fossil CO2 emissions within the iron and steel sector in Austria.

Dual fluidized bed based technologies for carbon dioxide reduction — example hot metal production

“…Recently published results indicate important economic aspects with respect to a further implementation of the presented concept. Main findings show that biomass based concepts could be economically feasible if the biomass price, the natural gas price and the price for CO 2 emission certificates provide a reasonable development with respect to the political aims formulated by the European Commission [36,37]. A quick acceleration of accompanying implementation steps is demanded, if there should be any chance to reach the climate targets from the latest Paris Agreement.…”

Decarbonising Industry via BECCS: Promising Sectors, Challenges, and Techno-economic Limits of Negative Emissions

“…This is already the case at Emirates Steel in Abu Dhabi, where 0.8 Mt CO 2 / year is captured for use in enhanced oil recovery (EOR) [8]. Combined with CCS, a biogenic reducing gas [59,60] could theoretically allow for "carbon negative" DRI steel [48•, 50]. Similarly, BECCS in smelt reduction steelmaking routes, such as Corex and the under-development HIsarna process, which are also more fuel-flexible than blast furnace steelmaking, could also allow for carbon-neutral or -negative steel [50, 58•].…”

“…Carbon storage in concrete [62•] or buried biochar [79] may also result in long-term storage, though biochar carbon may be partially re-released over time, and carbon storage in concrete is dependent on how the concrete is disposed. In contrast, carbon in short-lived products such as urea, paper products, or olefins, as considered in [44,59,[67][68][69], will rerelease CO 2 during use or disposal, and thus, carbon in these products should not be counted towards negative emissions.…”

Opportunities and challenges for engineering construction materials as carbon sinks

“…In the case of steel, improved production methods (e.g. lower CO2 energy sources and/or recycling [132,133]) could lead to a 50-89% reduction in CO2 emissions from production [133,134], and energy-CCUS can further benefit such materials.…”