Process analysis of methanol production using syngas from biochar steam gasification

Abstract

The master's thesis investigates the methanol production process, which is produced from syngas by biochar steam gasification. Besides gasification, the design includes syngas cleaning and methanol production. The syngas is purified to make its composition suitable for methanol production. After syngas purity adjusting, necessary amount of electrolytic hydrogen is added to achieve correct stoichiometric ratio of hydrogen in syngas. This results a high hydrogen content syngas. Although hydrogen is produced via electrolysis, this electrolytic process is not simulated in this thesis work. The process is simulated using Aspen plus. The impact of limiting factors of biochar, such as the carbon content and impurity levels, on the product are determined. Feasibility of the total process is studied by calculating profitability, doing sensitivity analysis and estimating CO₂ emission. Estimated emissions can be compared to fossil-based processes. Prices, impurity levels and CO₂ footprints of different origin of biochar, such as waste wood and agricultural residues, are compared. As a final target is to compare all combinations in technoeconomic and CO₂ equivalent standpoint.