猪场废水处理中的沼气热电联产工程案例分析

Case analysis of biogas heat and power cogeneration in piggery wastewater treatment

中高浓度畜禽废水处理中的沼气热电联产是保障沼气工程常年稳定运行的有效手段。以典型猪场废水处理沼气热电联产工程为案例,在工程介绍的前提下,引入相关数学模型,对沼气热电联产相关工艺参数进行了计算分析,结果表明,该工程沼气产量最高为1 678 m3/d,沼气发电机组发电效率为31.3%,发热效率为38.8%,总发电效率为70.1%,该沼气工程投资回报期为3.6年;CSTR厌氧罐秋季可达温度为24.3℃,冬季为15.9℃,CSTR厌氧罐内温度分布为秋季罐内平均温度T5.4(换热器顶部温度)=25.4℃,平均温度梯度grad1=1.83℃/m,grad2=0.80℃/m;冬季T5.4=19.6℃,grad1=1.44℃/m,grad2=1.06℃/m;通过参数分析,搅拌器宜尽可能置于换热器所在区域,并控制进水量稳定以保证CSTR厌氧罐的消化效果。

The biogas heat and power cogeneration in middle and high concentration livestock and poultry wastewater treatment is an effective means to keep the stable operation of biogas engineering over the whole year. A typical biogas heat and power cogeneration engineering in the piggery wastewater treatment was chosen as a case. On the premise of the engineering introduction,the related process parameters in biogas heat and power cogeneration were calculated and analyzed via the establishment of the mathematical models. The results show that the highest biogas yield in this project is 1 678 m3/ d. The efficiency of power generation is 31. 3%. The heating efficiency is 38. 8%.The total power generation efficiency is 70. 1%. The investment return period of this biogas engineering is 3. 6 years.The average temperature of CSTR anaerobic tank is 24. 3℃ in autumn under the ideal condition such as heat transfer uniformly,as it is 15. 9℃ in winter. The temperature in the top of the heat exchanger T5. 4and the temperature gradient grad were put forward to characterize the temperature distribution in CSTR anaerobic tank. In autumn,T5. 4= 25. 4℃,grad1= 1. 83℃ / m,grad2= 0. 80℃ / m. In winter,T5. 4= 19. 6℃,grad1= 1. 44℃ / m,grad2= 1. 06℃ / m. By means of parameter analysis,to keep digestion efficiency of CSTR anaerobic reactor,the stirrer should be put in the area of the heat exchanger as far as possible,the input quantity should be stable.