Conditions of using propeller stirring in biogas reactors

Abstract

Preparing and further cutting of bovine dung which also contains straw, and of corn silage happens in special cutters, from which it is fed into the pre-fermentation tank. The primary mixing of liquid manure, and sewage water, including other fluids happens in a heated pre-container. The foodstuffs which are their expiration dates, and various other waste (household waste, greasy materials from washing, depleted frying oil, fats from grease-traps, etc.) are accepted in the pounder. This is where the cutting and separation of wrappings of boxed products happens as well, after which the thin parts are fed into an autoclave, and kept at 70oC for at least four hours to sterilise them.The profit-oriented biogas plants consider the static, calculable production of electric and heat energy a fundamental goal, which requires the gas production to be continuous and free of hindrances [1]. In case of these factories, the gas yield for time unit may be lowered by various operation factors, but mainly malfunctions (errors, the foam within fermentation tanks from time to time, etc.). Incorrectly mixing or homogenising the materials arriving in the fermentation tanks also counts as a hindering operation factor. Our work details the basic questions of how the stirring inside fermentation tanks happens physically.

Operational Parameters of Biogas Plants: A Review and Evaluation Study

“…Different types of stirrers can be installed: submersible, long-axis, axial, and paddle stirrers [3]. The digester's form and size as well the used substrates are the main parameters used to choose the most suitable technology [3,103,104]. The previously mentioned mechanical stirrers vary, mainly according to their impeller velocities and sizes as well as the power consumption [91].…”

Literature Review on Solar Energy and Biogas Utilisation for the Development of Scalable Co-Generation Power Plants

“…[62]. This kind of technological problems can be solved mainly by adequate stirring [63], [64], and sometimes the more precise preparation of the input material (e.g. right size chopping) can help to avoid the inconveniences [65].…”