天津市典型生物质固体燃料锅炉NO、CO排放研究

针对实际运行条件下,国内生物质固体燃料燃烧过程中NO、CO排放研究不足,排放现状不清晰等问题,在天津地区选择了6台具有代表性的生物质固体燃料锅炉,在测试中燃烧其常用燃料,采用烟气分析仪Testo350对锅炉展开了气态排放研究,重点研究了其中5台生物质固体成型燃料锅炉在不同燃烧负荷下,NO和CO的排放情况,以及另1台捆烧式锅炉在正常工况下的排放情况。测试结果表明:6台生物质锅炉的NO排放浓度均在180 mg/m~3以上,CO排放浓度均高于500 mg/m~3。其中,3台炉型的固体成型燃料锅炉随着燃烧负荷的增大,NO排放浓度降低CO浓度升高,燃烧负荷控制在75%~80%可相对减少气态污染物NO、CO的排放,其余2台炉型NO、CO排放浓度随燃烧负荷的增大变化趋势与前3台相反,且燃烧负荷控制在95%左右为优;捆烧式锅炉NO排放浓度最低为182.9 mg/m~3,但CO排放浓度却高达2 243.6 mg/m~3。研究结果可为用生物质固体燃料锅炉的实际运行提供参考,从而优化生物质固态燃料的燃烧和排放。

STUDY ON EXCESS SLUDGE REDUCTION FROM WASTEWATER TREATMENT PLANT AND DEWATERING IMPROVEMENT BY HYDROTHERMAL METHOD

In order to achieve sludge reduction and improve the property of sludge dewatering,the excess sludge with higher organic matter,produced by biological treatment of food processing wastewater,was treated by the hydrothermal method.The results showed that hydrothermal reaction temperature and reaction time have significant effect on the sludge reduction,while initial water content of sludge was margin.Additionally,the optimum parameters for sludge reduction were at 220℃,reaction time of 3h with initial water content of 84％.Under the optimal conditions,from mass balance point of view,it showed that wet weight reduction of sludge was above 72.9％,dry weight reduction of sludge was above 31.2％,sludge VSS degradation rate reached up to 35.5％,the water content of sludge after hydrothermal reaction and filtration dehydration dropped to 59.4％,COD concentration in the filtrate was about 38.2g/L,in addition,the filtrate also contained a certain concentration of nitrogen and phosphorus.However,there was no significant effect on the load of food processing wastewater treatment when the dehydration filtrate returned to the wastewater treatment system.So hydrothermal treatment could reduce significantly the excess sludge produced by biological treatment of food processing wastewater,and improve its dehydration property greatly.