(630d) CO2 Utilization for Methanol Production As an Intermediate for Formaldehyde: Technoeconomic and Sustainability Assessment of the Value Chain in the Case of Sweden

To enable CO₂ re-utilization, a study in West Sweden aimed to identify partnerships between companies producing CO₂ and companies that may reuse CO₂ in their industrial processes. The study was initiated by a methodology for location, quantification and characterization of CO₂sources providing the first test-bed with large replication potential to other regions in Europe. The test-bed currently focuses on technologies mature enough to be implemented in a short-term timescale (5 to 10 years). On this basis methanol production has been prioritized as one of the technologies where emphasis should be given (e.g., some of the others being algae production, horticulture production, power to gas, concrete curing, mineral carbonation, etc.).

Methanol is one of the most common platform chemicals (i.e., a precursor of MTBE, DME, formaldehyde, acetic acid, ethanol, olefins, etc.) and is traditionally produced from synthesis gas (syngas). Syngas is mainly produced by the reforming of natural gas; however, gasification of solid (e.g., wood residues, coal) and liquid (e.g., black liquor from pulp and paper industries, refinery by-products) fuels is also gaining attention. The global annual use of fossil-derived syngas is approximately 6 EJ, 10% of which is used for methanol production. Currently, the methanol synthesis plants operate in a stable, high-throughput production mode at low CO₂/CO ratios in feed (e.g., preferred by copper catalysts up to concentrations of 10-12% CO₂). It is an issue of on-going research to develop catalysts and processes that can utilize high-CO₂content feeds in a techno-economically viable operating mode (generally high pressures, low temperatures are preferred for increasing the methanol yield).

Depending on the source of CO₂, hydrogen, the other methanol synthesis reactant, may be already present in the gas mixture (e.g., syngas from gasification, steel work off-gases), may be available from a different industrial source or provided from water hydrolysis using external, cheap energy sources (e.g., surplus energy from the grid). Hybrid solutions have also been proposed, e.g., where methanol is produced by combining biomass based synthesis gas with steel plant off-gases typically having very diverse composition (e.g., 3-65% H₂, 5-60% CO, 0-20% CH₄, 2-25% CO₂, 3-55% N₂) and LHV values (e.g., 3-18 MJ/Nm³).

This study focuses on the perspective of utilizing available industrial CO₂ sources to produce methanol as an intermediate for the subsequence synthesis of formaldehyde, which is of particular industrial interest for chemical production companies in West Sweden. It compares 6 process alternatives of different technology readiness level (TRL), including synthesis routes through the reversed-water-gas-shift reaction, formic acid, organo-carbamates, methyl formate, dimethyl carbonate and an upcoming indium oxide based technology. Rigorous process modelling is used to provide the necessary data for the technoeconomic (i.e., considering CAPEX and TRL) and sustainability (i.e., considering LCA and hazard assessment). The potential impact of impurities is discussed for the whole value chain from the CO₂ and H₂ sources to methanol and the subsequent formaldehyde production. The assessment considers uncertainties in the information for the CO₂ and H₂sources, the process modelling, and various future scenarios in the development of the energy technology sector.