Deriving Economic Potential and GHG Emissions of Steel Mill Gas for Chemical Industry

Jason Collis,Reinhard Schomäcker,Arno Zimmermann,Till Strunge,Bernhard Steubing

doi:10.3389/fenrg.2021.642162

Abstract

To combat global warming, industry needs to find ways to reduce its carbon footprint. One way this can be done is by re-use of industrial flue gases to produce value-added chemicals. Prime example feedstocks for the chemical industry are the three flue gases produced during conventional steel production: blast furnace gas (BFG), basic oxygen furnace gas (BOFG), and coke oven gas (COG), due to their relatively high CO, CO2, or H2 content, allowing the production of carbon-based chemicals such as methanol or polymers. It is essential to know for decision-makers if using steel mill gas as a feedstock is more economically favorable and offers a lower global warming impact than benchmark CO and H2. Also, crucial information is which of the three steel mill gases is the most favorable and under what conditions. This study presents a method for the estimation of the economic value and global warming impact of steel mill gases, depending on the amount of steel mill gas being utilized by the steel production plant for different purposes at a given time and the economic cost and greenhouse gas (GHG) emissions required to replace these usages. Furthermore, this paper investigates storage solutions for steel mill gas. Replacement cost per ton of CO is found to be less than the benchmark for both BFG (50–70 €/ton) and BOFG (100–130 €/ton), and replacement cost per ton of H2 (1800–2100 €/ton) is slightly less than the benchmark for COG. Of the three kinds of steel mill gas, blast furnace gas is found to be the most economically favorable while also requiring the least emissions to replace per ton of CO and CO2. The GHG emissions replacement required to use BFG (0.43–0.55 tons-CO2-eq./ton CO) is less than for conventional processes to produce CO and CO2, and therefore BFG, in particular, is a potentially desirable chemical feedstock. The method used by this model could also easily be used to determine the value of flue gases from other industrial plants.

Highlights

Greenhouse gas (GHG) emissions such as CO2 from industry continue to rise worldwide despite efforts to decrease emissions, such as stated in the 2015 Paris agreement, which aims to limit global warming to 2◦C and make efforts to limit it to 1.5◦C (Jarraud and Steiner, 2014; IEA, 2017; Rogelj et al, 2018)
The replacement costs of CO are significantly lower than the benchmark for all scenarios of blast furnace gas (BFG) and basic oxygen furnace gas (BOFG), and the replacement costs for H2 from coke oven gas (COG) are slightly lower than the benchmark
When used as feedstock for CO, the replacement costs for BFG are about half when compared to the replacement costs for BOFG

Summary

Introduction

Greenhouse gas (GHG) emissions such as CO2 from industry continue to rise worldwide despite efforts to decrease emissions, such as stated in the 2015 Paris agreement, which aims to limit global warming to 2◦C and make efforts to limit it to 1.5◦C (Jarraud and Steiner, 2014; IEA, 2017; Rogelj et al, 2018). There are many possible process routes for decarbonizing the steel industry (He and Wang, 2017), [(Hasanbeigi et al, 2014), both in the iron-making and steelmaking parts of the process These are yet to see actual implementation and often end up stuck in the development stage. Investment cycles in the industry are comparably long due to a combination of factors such as the age and conservative nature of the industry, the fact that the steelmaking process has not changed significantly in a long time, and the vast investment costs required to build a steel plant, as well as the lifetime of the plant (Arens et al, 2017) This makes it challenging to implement process changes that reduce emissions within the Paris agreement’s time scales. COG and BOFG are potentially useful gases as a chemical feedstock due to the comparably high H2 and carbon content, respectively (Joseck et al, 2008)

Objectives

Results

Discussion

Conclusion