Essential technical parameters for effective biogas production

Abstract

Rising agrarian raw material prices in 2006 had a negative impact on the biogas sector in Germany, leading to the search for potentials for optimisation of production. A problem is the workload of the block-type thermal power station (BTPS). This is caused by biogas process disturbances, construction errors, technical problems and management mistakes as well as by oversizing of the BTPS. Technical problems appear in particular with BTPS and aggregates, stirring devices and fermenter heatings, measuring and control technology as well as foil caps. The BTPS is an essential part of the economic efficiency of biogas production. A 2% increase in efficiency, to 40%, lowers the costs about 1 Cent kWhef'. To achieve sufficient stirring power, the device type, heights and angle adjustment are vital. The substrate dosing engine must be adjusted to the particular substrates. The fermentation has to be controlled continuously. Parameters such as substrate amount, temperature, pH-factor, fermenter chamber load, gas amount and composition, ammonium concentration and short-chained fatty acids should be controlled regularly. Large temperature variations can lead to foam formation, resulting in a reduction of the gas yield. Disinfectants, antibiotics and a too tall fermenter chamber load can also have a negative influence. Low methane content often may often result from high sulphur and ammonia content in biogas composition, high aerial dosage accompanying desulphurisation as well as to coarse input material.