| abstract |
A process and an apparatus for the manufacture of biogas and a solids fraction from an organic waste feedstock is provided. The process involves thermal hydrolysis of the organic waste feedstock at a temperature from about 100 to about 220° C., a pressure from about 5 to about 20 bars, for a period of time from about 15 minutes to 4 hours, to produce a hydrolysate. The hydrolysate undergoes anaerobic digestion at a temperature from about 25 to 60° C., for a period of time from about 1 to 35 days to produce a biogas stream and a digestate. The digestate is separated into a solids fraction and a liquid fraction, and a portion of the solids fraction is recycled for further anaerobic digestion. The biogas stream, characterized as having a methane content from between 55 to 80% by volume, and the solids fraction, are recovered. The apparatus includes a receiving bin for receiving and supplying organic waste feedstock to a thermal hydrolysis reactor. The thermal hydrolysis reactor for processing the organic waste feedstock at a temperature from about 100 to about 220° C., a pressure from about 5 to about 20 bars, for a period of time from about 15 minutes to 4 hours to produce a hydrolysate. An anaerobic digester for processing the hydrolysate at a temperature from about 25 to 60° C., for a period of time from about 1 to 35 days to produce the biogas and a digestate, and a solids thickening tank for separating the digestate into the solid fraction, a liquid fraction and a secondary biogas fraction. |