| Intensive large-scale livestock and poultry farming has promoted the improvement of the national economy and quality of life.However,the environmental pollution caused by its excreta is becoming more and more serious.Aerobic composting is generally considered an effective method for the treatment of feces and other organic wastes due to its clean,harmless and resource-utilizing properties.Its essence is mainly to use the biochemical metabolism function of microorganisms to degrade organic components in feces,and eventually become a stable high-value compost product Further,the bio-oxidation process is usually accompanied by the production and release of heat,we found that most of the heat released during the composting is diffused into the environment in form of waste heat.If waste heat can be recycled and transformed,its engineering application prospects will be very broad.However,Composting involves complex biochemical reactions,which thermogenic capacity and distribution of heat setting parameters are closely related to composting.Therefore,this thesis explored the influence of different parameters(mass ratio and oxygen supply rate)of heat generated during composting and heat distribution,and through optimization analysis to get the best compost parameters to design an innovative portable heat.Based on the power recovery system to optimize results,it is intended to compost waste heat recovered by heat conduction and thermoelectric generation principles.The main research results are as follows:(1)With different parameters,which is significantly different heat production Firstly,the test results of different material ratios show that the biochemical heat generation capacity of group S2 is much higher than that of groups S1 and S3,and their values are 0.88×105 KJ,1.26×105 KJ,and 1.01×105KJ in this order.Secondly,four sets of different oxygen supply test data show that when the flow rate is increased from 0.15 to 0.30 L·min-1·kg-1 OM,the heat output increases to 2.37 times.However,when the aeration volume continued to increase to 0.6 and 0.9 L·min-1·kg-1 OM,the heat generation capacity began to decrease,but it was still higher than 0.15 L-min-1·kg-1 OM.(2)The heat distribution path and ratio are closely related to the compost-related parameters.Through RDA analysis,the results show that the material ratio and oxygen supply have significant effects on the temperature of the reactor body and the total heat production(P<0.01),however,the material ratio has no significant difference in the heat distribution of the compost,especially the convective heat transfer and the heat at the air outlet,which is P=0.3332.The difference is that the amount of oxygen supply is closely related to the heat distribution(P=0.005).And the arrow of response value(heat conduction and accumulated heat)shows obtuse angle,while the arrow of response value(convective heat transfer and outlet heat)shows acute angle,which indicates that convective heat transfer and outlet heat have a positive correlation with oxygen supply.(3)In this research,based on the optimized compost parameter scheme,an innovative and simple method of waste heat recovery for composting was designed——the thermoelectric heat recovery system,which effectively captured the waste heat released during the composting process without changing the original structure of the reactor.energy.The test results show that the installed thermoelectric system with an area of only 0,04m2 produces different output power with the temperature gradient of the reactor.Among them,the average voltage value of the T1 group in the high-temperature stage is 3.58V,while the T2 group is only 2.52V.Correspondingly,the total power generation of the T1 and T2 groups is 12.53 Ah and 15.82 Ah,respectively,which is also the key to improve the efficiency of thermoelectric conversion.In addition,according to the analysis results of the compost maturity test index,it can be concluded that the installation of the heat recovery system has no effect on the compost reaction and the final quality.On the contrary,it contributes to the degradation of organic matter to a certain extent during the composting process. |
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