Page 283 - Low Temperature Energy Systems with Applications of Renewable Energy

Biofuels conversion: energy-saving processes and use of biogas 269

Fig. 7.10 Schematic energy-saving diagram of the bioconversion process.

problems of heat re-use and lower costs for the technological process of biogas produc-
tion. The schematic energy-efficiency technological diagram of the bioconversion pro-
cess in a biogas reactor plant (BGP) is shown in Fig. 7.10. The substrate from the
storage tank after grinding and sterilization in the substrate preparation unit enters
the bioreactor. The process of anaerobic fermentation is more effective when it is
intensified and thermostabilized. Intensifying the process of biogas release is possible
by mixing the organic mass by vibrating activation, bubbling or mechanical means. An
important aspect of the stability of the thermal regime in the bioreactor is the heating of
the substrate and the simultaneous thermal insulation of the walls of the reactor from
fluctuations in ambient temperatures.
The heat of the output gas mixture and spent biomass is an effective source of en-
ergy that is reused for the processes inside the bioreactor. Such thermostabilization
systems are provided by using a heat pump or heat exchanger. Due to the re-use of
heat, high energy efficiency is achieved in the anaerobic fermentation process, and
the bioreactor productivity is significantly increased.