發(fā)布時間：2018-06-30 20:17

  本文選題：暗河厭氧反應器 + 發(fā)酵��； 參考：《華中科技大學》2016年博士論文

【摘要】：由于養(yǎng)殖廢水具有廢水量大、有機物質濃度高,及含有豐富的氮磷等營養(yǎng)物質,對水體構成了嚴重的危害,并制約了養(yǎng)殖業(yè)的進一步發(fā)展。養(yǎng)殖廢水的處理問題成為了目前亟需解決的迫切問題。本文采用暗河式厭氧發(fā)酵反應器處理養(yǎng)殖廢水,利用廢水自身的重力形成一個自上而下的流動體系,解決了原料流態(tài)化連續(xù)進料出料的關鍵技術：并利用自身的堆肥系統(tǒng)在堆肥過程中產生的熱量為反應器加熱保溫,保證厭氧反應在中溫的溫度范圍內進行：同時針對厭氧反應的不穩(wěn)定性,提出了厭氧消化反應過程的監(jiān)控指標使得能夠及時掌握厭氧反應的狀態(tài),為大規(guī)模處理養(yǎng)殖廢水及生產沼氣鋪平了道路。圍繞該工藝的構建,本文展開了以下工作：(1)以春夏秋冬為時間點,分析了堆肥系統(tǒng)對于反應器的保溫效果。結果表明,堆肥系統(tǒng)為反應器能夠起到很好的保溫效果。反應器春夏秋冬四季的平均溫度分別可以達到25.2℃,34.6℃,25.6℃和19.3℃。即使在冬天,反應器的最低溫度可以達到15.7℃。同時分析了對比了幾種不同加熱方式的成本,發(fā)現(xiàn)堆肥加熱方式的成本最低。(2)對暗河式厭氧反應器的最佳運行條件進行了研究,考察了不同的污泥接種率、不同的有機負荷及水力停留時間對厭氧消化產氣率、氣體成分、有機物去除率的影響,并分析了厭氧消化過程中間產物揮發(fā)性脂肪酸、氫氣及硫化氫的變化,以及氫氣和硫化氫對于厭氧消化過程的影響。實驗結果表明,隨著接種比和負荷的提升,厭氧反應過程出現(xiàn)了抑制作用,從而導致了產氣量和有機物去除率的下降。最佳的污泥接量為35%,最佳的負荷為5.3 gCOD/L,水力停留時間為25天。此時,日平均產氣量為26.7 L,最大產氣速率為4.96 L/L.d,有機物去除率達到79.10%。(3)以ADM1模型為基礎,加入氫氣、硫化氫及pH值三種抑制因子,建立了底物降解模型、中間產物生成模型及產氣量模型,同時分析了COD、乙酸、丙酸和丁酸對于各個動力學參數(shù)的敏感度以及氫氣、硫化氫及pH值對于厭氧消化過程的影響。最后比較了氫氣、硫化氫及pH值三種因子對于厭氧消化過程的影響大小。結果表明,該模型能夠很好的預測厭氧消化過程底物的降解及沼氣產氣量,同時發(fā)現(xiàn)隨著負荷的提高,厭氧消化出現(xiàn)了抑制因素,具體體現(xiàn)在氫氣和硫化氫濃度的提高。通過k值發(fā)現(xiàn),在最佳的負荷條件下,其有機物的降解速率(km_COD)最大。隨著負荷的升高,氫氣和硫化氫濃度也隨著升高,從而影響了微生物的活性,降低了底物降解速度。從ka、kb和kp的變化可以看出乙酸、丙酸和丁酸轉化成甲烷的順序是丙酸丁酸乙酸。不同負荷條件下的fa值為7.5 (4.2 g/L),6.4 (5.3 g/L),2.0 (7.0 g/L) 4.5 (9.0 g/L);fb值為1.3 (4.2 g/L),1.9 (5.3 g/L),1.2 (7.0 g/L) 1.0 (9.0 g/L);fp值為1.0 (4.2 g/L),2.1 (5.3 g/L),3.3 (7.0 g/L) 2.3 (9.0 g/L);而從fa、fb、fp、的變化,可以看出長鏈的脂肪酸首先被轉化成乙酸,其次是丁酸,最后是丙酸。通過敏感度分析發(fā)現(xiàn),初始的有機物濃度即有機負荷的變化是最影響上述幾個變量的因子,這與實驗結果一致。(4)針對厭氧消化過程的不穩(wěn)定性,以葡萄糖、蛋白質、脂類物質及實際的廢水模擬負荷擾動實驗,分析了厭氧消化系統(tǒng)負荷受到沖擊時,產氣量、氣體成分、pH、總揮發(fā)性脂肪酸、單個的揮發(fā)性脂肪酸、氫氣及硫化氫的變化,以反應速度、監(jiān)測手段及敏感程度作為選擇監(jiān)控指標的標準。結果表明,反應器在穩(wěn)態(tài)運行的條件下,沼氣產量為26.7±3.5 L/d,甲烷含量為62.1%±3.5%,氫氣和硫化氫的濃度分別為5±1.5ppm和1000±50 ppm,乙酸、丙酸和丁酸的濃度為5.1±1.5 mg/L、6.5±1.2 mg/L和9.5±1.3 mg/L,總的揮發(fā)性脂肪酸的濃度為4.8±1.5mg/L, pH值在6.8-7.05之間。當系統(tǒng)受到負荷沖擊時,氫氣、硫化氫、產氣量、丁酸、總的揮發(fā)性脂肪酸對負荷沖擊表現(xiàn)出積極的反應,而氣體成分、pH、乙酸和丙酸的變化則不明顯。幾種物質對負荷沖擊的響應順序為：氫氣硫化氫丁酸TVFA產氣量。但由于丁酸及TVFA監(jiān)測手段的復雜性及產氣量的響應滯后性,最終選擇氫氣和硫化氫作為厭氧消化過程的監(jiān)控指標。(5)最后分析了系統(tǒng)的環(huán)境效益、能量平衡及經濟效益。結果表明,暗河式沼氣反應器由于利用自身堆肥產生的熱量為反應器保溫,與其他的加熱方式相比,可以至少節(jié)約5倍的能源。此外,由堆肥產生的額外經濟效益也十分明顯。
[Abstract]:Because of the large amount of waste water, high concentration of organic matter and rich nitrogen and phosphorus, aquaculture wastewater constitutes a serious harm to the water body and restricts the further development of the aquaculture industry. The treatment of aquaculture wastewater has become an urgent problem to be solved at present. This paper uses a dark river anaerobic fermentation reactor to treat culture. Wastewater, using the gravity of the wastewater to form a top-down flow system, solves the key technology for the continuous feeding of raw materials in the flow state of the raw material: the heat produced by its own composting system during the composting process is heated for the reactor to ensure that the anaerobic reaction is carried out in the temperature range of the medium temperature and at the same time against the anaerobic reaction. In response to the instability, the monitoring index of anaerobic digestion process has been put forward to enable the state of anaerobic reaction to be mastered in time, which paved the way for large-scale treatment of aquaculture wastewater and biogas production. Following the construction of this process, the following work has been carried out in this paper: (1) to analyze the composting system for the reactor in spring, summer and winter. The results show that the composting system can have good thermal insulation effect for the reactor. The average temperature of the reactor in spring summer, autumn and winter can reach 25.2, 34.6, 25.6 and 19.3. Even in winter, the minimum temperature of the reactor can reach 15.7. At the same time, the cost of several different heating modes is analyzed and compared. The cost of the current compost heating method is the lowest. (2) the optimum operating conditions of the dark river anaerobic reactor are studied. The different sludge inoculation rate, the different organic load and the hydraulic retention time on the anaerobic digestion and gas production rate, the gas composition and the organic matter removal rate are investigated, and the volatility of the intermediate product in the anaerobic digestion process is analyzed. The changes in fatty acids, hydrogen and hydrogen sulfide, and the effect of hydrogen and hydrogen sulfide on the anaerobic digestion process. Experimental results show that the anaerobic reaction process has a inhibition effect with the inoculation ratio and the increase of load, which leads to the decrease of gas production and organic matter removal rate. The optimum sludge connection is 35% and the optimum load is 5.3 gCOD/. L, the hydraulic retention time is 25 days. At this time, the daily average gas production rate is 26.7 L, the maximum gas production rate is 4.96 L/L.d, the organic matter removal rate is 79.10%. (3) based on ADM1 model, adding hydrogen, hydrogen sulfide and pH value three inhibitory factors, the substrate degradation model, the intermediate product generation model and the gas production model, and the analysis of COD, acetic acid, are established. The sensitivity of propionic acid and butyric acid to various kinetic parameters and the effect of hydrogen, hydrogen sulfide and pH on the anaerobic digestion process. Finally, the effects of three factors such as hydrogen, hydrogen sulfide and pH value on the anaerobic digestion process are compared. The results show that the model can pretest the degradation of substrate and biogas production in the anaerobic digestion process. At the same time, it was found that the anaerobic digestion was inhibited with the increase of the load, which was embodied in the increase of hydrogen and hydrogen sulfide concentration. The K value was found that the degradation rate of organic compounds (km_COD) was the largest under the optimal load condition. As the load increased, the hydrogen and hydrogen sulfide concentration also increased, thus affecting the microorganism. Activity, reducing the rate of substrate degradation. From the changes of Ka, KB and KP, it can be seen that the order of acetic acid, propionic acid and butyric acid into methane is butyric acid propionate acetic acid. The FA value of different load conditions is 7.5 (4.2 g/L), 6.4 (5.3 g/L), 2 (7 g/L) 4.5 (9 g/L), FB value 1.3 (4.2 g/L), 1.9 (5.3 g/L), 1.2 (7 g/L)); 1.2 (7 g/L); For 1 (4.2 g/L), 2.1 (5.3 g/L), 3.3 (7 g/L) 2.3 (9 g/L), and from the changes of FA, FB, FP, it can be seen that the long chain fatty acids are first converted into acetic acid, followed by butyric acid, and finally propionic acid. By sensitivity analysis, the initial organic concentration, that is, the change of organic load is the most influential factor of the above variables, which is the experiment with the experiment. 4. (4) according to the instability of anaerobic digestion process, with glucose, protein, lipid materials and actual wastewater simulated load disturbance experiments, the changes of gas production, gas composition, pH, total volatile fatty acids, single volatile fatty acids, hydrogen and hydrogen sulfide were analyzed when the load of anaerobic digestion system was impacted. Degree, monitoring means and sensitivity are the criteria for selecting monitoring indexes. The results show that the biogas production of the reactor is 26.7 + 3.5 L/d, methane content is 62.1% + 3.5%, hydrogen and hydrogen sulfide are 5 + 1.5ppm and 1000 + 50 ppm respectively, and the concentration of acetic acid, propionic acid and butyric acid is 5.1 + 1.5 mg/L, 6.5 + 1.2 mg/L and 9.5. 1.3 mg/L, the total concentration of volatile fatty acids is 4.8 + 1.5mg/L, and the pH value is between 6.8-7.05. When the system is subjected to load shock, hydrogen, hydrogen sulfide, gas production, butyric acid, and total volatile fatty acids have a positive reaction to the load impact, while the changes of gas components, pH, acetic acid and propionic acid are not obvious. The response sequence is: hydrogen sulfide butyric acid TVFA gas production. But due to the complexity of butyric acid and TVFA monitoring means and the response lag of gas production, the final selection of hydrogen and hydrogen sulfide as the monitoring index of the anaerobic digestion process. (5) finally, the environmental benefits, energy balance and economic benefits of the system were analyzed. The results showed that the dark river type biogas was reversed. The heater can save at least 5 times as much energy as other heating methods because of the heat generated by its own compost. In addition, the additional economic benefits from the composting are also obvious.
【學位授予單位】：華中科技大學
【學位級別】：博士
【學位授予年份】：2016
【分類號】：X713

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