Evolution and Prospects of Hydrothermal Carbonization

Hydrothermal carbonization enables the valorization of biomass via thermochemical conversion into various products. Today, this technology is experiencing a situation similar to that experienced in the past by other process technologies. Of these technologies, some have become important industrial realities, such as reverse osmosis, while others have never been able to establish themselves fully. This paper presents a brief overview of this technology’s current status, highlighting its strengths and various drawbacks. The primary purpose of the research activity is to identify a possible future scenario toward which this technology is heading. Hydrothermal carbonization has already been established on a laboratory scale for some time, and now it is in a transitional phase between pilot-scale and industrial-scale applications. The interest that HTC has aroused and continues to arouse is evidenced by the growing number of publications and patents published. In particular, the uniform percentage of patents filed in various countries testifies to the worldwide interest. This technology has advantages but also some bottlenecks that have yet to be overcome. Process integration, higher-capacity plants, and the use of Industry 4.0 technologies seem to be the most interesting options to overcome the last limiting factors and make hydrothermal carbonization an established industrial reality.