(664a) Quantitative Risk Assessment of Solvothermal Conversion of Waste Plastics

Solvothermal conversion is a thermochemical process, where biomass is treated in the presence of a solvent at a temperature higher than the boiling temperature of this solvent. In the solvothermal process, the solvents play a significant role in overall conversion, distribution of products, and bio-oil yield and properties. For instance, the presence of organic solvents during the solvothermal process allows the product to contain important functional groups. At the same time, most of the organic solvents are flammable in nature. In addition, the solvothermal process is generally a high temperature and high-pressure process. So, a significant risk should always exist associated with the solvothermal process.

Due to the success in a laboratory scale, people are thinking about it’s commercialization. As soon as we think about the large scale, the risk associated with the design comes to the place. As part of the conceptual design, the hazards associated with the solvothermal process should be reviewed and identified the critical assumptions to support safe operations. To the best of authors’ knowledge, no study has been reported on the risk associated with the solvothermal process and how it changes with the plant capacity. Therefore, a detailed safety study of the solvothermal process is urgently required.

In this study, solvothermal processes, the capacity of handling 1 to 100 Mt/day waste plastic as feedstock, has been considered. A complete hazard identification along with the risk assessment were completed. During the risk analysis, two different release cases were considered i) loss of containment and ii) leak from the reactor. In this analysis, different possible ways to propagate the release scenarios such as flammable and toxic gases, Boiling Liquid Expanding Vapor Explosions (BLEVE), Jet fires, etc. were studied. Results showed that the risk associated with the process is not linearly proportional to scale-up of the plant capacity.