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

9 6 Vol. 9 No. 6 2 0 5 6 Chinese Journal of Environmental Engineering Jun. 2 0 5 * 2 3 3. 20620 2. 20620 3. 30004 678 m 3 /d 3. 3% 38. 8% 70. % 3. 6 CSTR 24. 3 5. 9 CSTR T 5. 4 =25. 4 grad =. 83 /m grad 2 = 0. 80 /m T 5. 4 = 9. 6 grad =. 44 /m grad 2 =. 06 /m CSTR X703. A 673-908 205 06-2755-06 Case analysis of biogas heat and power cogeneration in piggery wastewater treatment Dai Ruobin Chen Xiaoguang Ji Guangkai 2 Wu Saiming 3 Yuan Liangping 3 Xiang Xinyi Zeng Xiangliu. State Environmental Protection Engineering Center for Pollution Treatment and Control in Textile Industry College of Environmental Science and Engineering Donghua University Shanghai 20620 China 2. Office of Teaching Affairs Donghua University Shanghai 20620 China 3. Hangzhou Qingcheng Energy Environmental Protection Engineering Co. Ltd. Hangzhou 30004 China Abstract 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 678 m 3 /d. The efficiency of power generation is 3. 3%. The heating efficiency is 38. 8%. The total power generation efficiency is 70. %. 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 5. 9 in winter. The temperature in the top of the heat exchanger T 5. 4 and the temperature gradient grad were put forward to characterize the temperature distribution in CSTR anaerobic tank. In autumn T 5. 4 =25. 4 grad =. 83 /m grad 2 =0. 80 /m. In winter T 5. 4 =9. 6 grad =. 44 /m grad 2 =. 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. Key words piggery wastewater anaerobic digestion biogas engineering heat and power cogeneration temperature gradient 2 5208087 2ZR400800 20200752000 223202D3-08 204-04 - 30 204-07 - 4 993 E-mail dairuobin@ 63. com * E-mail cxg@ dhu. edu. cn 3-6

2756 9.. 2 CSTR 2 3. 0 m 3. 4 m 500 m 3 3. 0 kg COD / m 3 d 7 HRT 8 d 30 d CSTR 2 8 9 80 8. 7 m h = 5. 4 m DN65 2 50 mm 5 0 CSTR UASB 2. 2 m 4. 5 m 500 m 3 5. 0 kg COD / m 3 d HRT 4 d 5 d CSTR 000 m 3.. 3 SBR. 6 000 350 m 3 20 m 3 - SBR SBR - 2 000 m 2. 5 m 203 8 000 m 2 400 m 3 /d.. 4 2 CSTR UASB Fig... Process flow SBR 2 3. 0 m 2. 3 m 5. 0 m 200 m 3 HRT 3. 0 d 2 d SBR 2 30 kw 30 m 3 /min SBR 500 m 3.. 5 50 kw 2 CSTR. 2 4 0. 8 m 2. 5 m. 2. 65 20 m 0 m 4. 4 m 800 m 3

6 2757 η = 50 3. 6 VCe 00% η % V 0. 288 kj/ m h α 2i m 3 /h C 23. 0 kj/ m 2 0. 6 e 35. 9 MJ /m 3. 2. 2 K i % 4 η 2 = W. 2. 5 CSTR hc ph ΔT 00% 2 CSTR VCe CSTR 5. 4 η 2 % W h m CSTR 3. m kg /h c ph 4. 2 kj / kg ΔT. 2. 3 grad /m 0 5. 4 m 5. 4 m 3. m UASB CSTR 0 5. 4 m E grad 5. 4 3. m E = C + PE grad 2 3 A grad = Δt 6 C Δh P grad 2 = Δt 2 7 A Δh 2 Δt CSTR 0 m 5. 4 m -4. 2. 4 CSTR 256 kj / m 2 h 3. 4 kj / m 2 h b i 0. m λ i h 4. 2 kj/ m 2 h Δh 0 m 5. 4 m 5. 4 m Δt 2 CSTR CSTR 5. 4 m 3. m Δh 2 5. 4 m 3. m 7. 7 m CSTR 2 tw h c ph ΔT = 24. 2 T - T 2 K i S i + Gρc T - T 2 4 t h T COD T 2 S i 300 m 2 COD 050 m 2 265 m 2 Table Effluent water quality and removal efficiency G index COD in structures of anaerobic process m 3 ρ 000 kg /m 3 c COD mg /L COD % 4. 2 kj / kg K i kj / m 2 h 6 000 CSTR 7 600 52. 5 UASB 700 77. 6 K i = + b i + 5 α i λ i α 2i 2. α i 203 0

2758 9 2 365 d Fig. 2 Relationships of biogas production 72 3 generated and days during startup 3. 6 2. 4 CSTR 2 2 678 m 3 / d 0. 38 m 3 /kg 5 8 COD 30 m 3 4 5 CSTR 50 kwh 24. 3 5. 9 90 kwh CSTR 2 0 3 4 CSTR 0 ~ 5. 4 8 9 m 5. 4 ~ 3. m 5. 4 m T 5. 4 6 7 80 m 3 2 550 m 3 /d 80% 600 m 3 /d 40% 3 4 5. 4 m T 5. 4 = 25. 4 80 m 3 η = 3. 3% 9. 6 grad 2. 2 2. 3 C UASB CSTR 200 P 5 80 m 3 550 m 3 /d 50 kw 2 900 kwh /d 0. 8 2 325 /d 600 m 3 /d 900 /d CSTR grad =. 83 /m grad 2 = 0. 80 /m 4 6. 3 T 5. 4 = =. 44 /m grad 2 =. 06 /m grad grad 2 CSTR 0 ~ 5. 4 m 5. 4 ~ 3. m 5 300 kg /h CSTR 26 56 20 50 30 2 3 4 η 2 = 38. 8% T 5. 4 70. %

6 2759 Fig. 3 3 CSTR T 5. 4 Temperature distribution in CSTR anaerobic reactor in autumn 678 m 3 /d 0. 38 m 3 /kg COD 2 3. 3% 85% 45% CSTR 38. 8% 70. % 3. 6 3 CSTR 24. 3 5. 9 CSTR 0. 80 /m T 5. 4 grad 2 =. 06 /m = 25. 4 grad =. 83 /m grad 2 = = 9. 6 grad =. 44 /m 4 CSTR Kornboonraksa T. Lee H. S. Lee S. H. et al. Application of chemical precipitation and membrane bioreactor hybrid process for piggery wastewater treatment. Bioresource Technology 2009 00 6 963-968 2.. 2005 25 5 32-38 4 CSTR Li Shulan Wu Xiaofu Liu Ying et al. Summarization for Fig. 4 Temperature distribution in CSTR anaerobic reactor in winter piggery wastewater treatment technology. Journal of Central South Forestry University 2005 25 5 32-38 in Chinese T 3. 5. 4. 2009 25 6 854-859 Yu Yi Zheng Ping Chen Xiaoguang et al. Three typical grad grad 2 fermentation utilization modes of biomass energy. Bulletin 4 of Science and Technology 2009 25 6 854-859 in 0 ~ 5. 4 m Chinese 4 Song Zilin Zhang Chao Yang Gaihe et al. Comparison of grad biogas development from households and medium and largescale 5. 4 ~ 3. m grad 2 biogas plants in rural China. Renewable and Sustain- able Energy Reviews 204 33 5 204-23 5 Chen Ling Zhao Lixin Ren Changshan et al. The progress and prospects of rural biogas production in China. CSTR grad Energy Policy 202 5 2 58-63 3 6 Christy P. M. Gopinath L. R. Divya D. A review on anaerobic decomposition and enhancement of biogas production through enzymes and microorganisms. -SBR- Renewable and Sustainable Energy Reviews 204 34 6 67-73

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