Life Cycle Assessment for Industrial Gas Production in China

Abstract

Purpose Industrial gases play an essential role in a wide range of sectors, including chemicals, metals, energy, and healthcare industry. There has been a strong push for disclosing environmental footprints of industrial gas products due to their high energy intensity production processes and the urgent need for industry decarbonization. This article aims for a comparative life cycle assessment of three main industrial gas products, oxygen, nitrogen and argon with sensitivity analysis for identifying major contribution of environmental impacts. Methods Existing production routes of industrial gases were reviewed. The life cycle assessment (LCA) method was used to study and evaluate the environmental footprints of three major industrial gas products produced by air-separation process. Life cycle inventory of each production stage was conducted based on the process unit, national standards and literature. Results The assessment results showed that life cycle global warming potential (GWP100) of oxygen, nitrogen and argon per 1,000 normal cubic meter are 460, 91 and 1,550 kg CO2 eq, respectively. Argon has the highest environmental and resource use impacts among all three gas products. Sensitivity analysis showed that electricity and steam consumption are the two most important factors affecting life-cycle carbon emissions and contributes more than 90% of the overall emissions. Conclusions The environmental footprint of oxygen can be decreased by 91% and 78% via replacing fossil fuel electricity with wind and solar power, respectively. As grid decarbonization taking place nation-wide, such interesting characteristics endowed industrial gases with enormous potential to achieve the decarbonization goal.