Conference article

Hydrothermal carbonization (HTC) is an artificial coalification process which converts raw biomass into a coal-like product; biocoal. Biocoal has a higher energy density than the original biomass and is easier to transport; store and process. Hence; HTC is recently promoted as an upgrading technology; especially for wet biomass. For HTC to become a commercial technology; it is essential to identify applications which offer technical or economic advantages over conventional biomass processes. This paper presents a process design where HTC is integrated with wood-fired combined heat and power production (HTC-CHP); and compares it to standalone HTC (HTC-sep) and to wood pelletizing integrated with CHP (WP-CHP). The respective plant designs are modeled with Aspen Plus and an economic analysis is performed using investment costs from literature. The overall efficiency of electricity; heat and wood or biocoal pellet production is very close in all considered cases. When biodegradable waste is available at zero cost; the production costs of biocoal pellets are similar to those of wood pellets. If wood chips are used as an HTC feedstock; the production costs are 32–38% higher. The average cost of CO2 avoidance is highest for the standalone HTC plant; due to the auxiliary consumption of natural gas and electricity.

Hydrothermal carbonization; biocoal; biomass; wood pellets