Research On Thermal Characteristics And Energy Efficiency Of Anaerobic Fermentation Reactor

Anaerobic fermentation reactor is an important means of biogas ferm entation engineering, because its internal reaction is very complex, therefore, studying the local flow and heat transfer process of fermentation in the reactor has been a considerable research value problem. Its heat energy directly affects the energy-saving effect of biogas projects and the ability to achieve a positive energy output. Reducing energy consumption is the key biogas reactor project in the northern cold regions where the working correctly Grasping the temperature distribution in the reactor is the basis for the process control of anaerobic fermentation process optimization, the temperature of the reactor control plays a vital role. In this paper, FLUENT software for velocity and temperature fields within the fermentation liquid were simulated based on the use of the basic principles of heat transfer, thermal properties of the reactor were analyzed. From the viewpoint of economy, if the reactor is too large, it makes poor economy of the reactor, if the volume is too small, it can not satisfy the conditions of a fermentation reaction. Therefore, this paper tangled reactor heat transfer surface area of the minimum structure size, and energy consumption and the insulation effect of the reactor were calculated and analyzed, while the whole biogas production capacity and consumption is predicted.The main contents and results as follows:(1) Analysis of the reactor heat transfer mechanism, a fermentation reactor on t he basis of the physical model, finite volume method for equations and boundary conditions are discretized control was divided evenly and stagger grid, discrete equations iterative solution. Using FLUENT software division multiple grid of reaction apparatus fermentation liquid velocity field, temperature field calculations, the situation at different times of the resulting flow and heat transfer are analyzed. It concluded that natural convection heat transfer can be ignored, according to the calculation of direct heat conduction.(2) Anaerobic fermentation reactor system thermal equilib rium is analyzed, build the corresponding heat transfer model.(3) With comparative analysis of a certain size, the surface area of the smallest of several reactors,inferred the topped reactor is the best choice.(4) Calculate the amount of heat the reactor containment structure of each part and the total amount of heat, analysis of the proportion accounted for a larger proportion of the sidewall surface obtained, sensible heat loss and water evaporation loss can be ignored.(5) In order to facilitate the reactor insulation, increase gas production rates and lower investment costs, obtaining its optimal thermal insulation thickness to ensure optimum yield based fermentation liquid temperature on the time when the insulation layer thickness exceeds 150 mm, reduce the amount of heat is not so obvious, so choose a thickness of 150 mm of insulation is most appropriate.(6) Biogas projects annual energy consumptions are analyzed, getting positive energy output of each month.