不同类型絮凝剂及其组合对于干式厌氧发酵沼液的深度脱水性能研究

Study on the Deep Dehydration Performance of Different Types of Coagulants and Their Combinations on Dry Anaerobic Fermentation Digestate

以干式厌氧系统沼液为研究对象,采用小试试验及板框压滤中试的方式,分析氯化铁(FeCl_(3)·6H_(2)O)、聚合硫酸铁(Polymeric Ferric Sulfate,PFS)、聚合氯化铝(Polyaluminium Chloride,PAC)与不同离子度型号的阳离子聚丙烯酰胺(Cationic Polyacrylamide,CPAM)絮凝剂对沼液絮凝脱水的影响。研究表明,单一使用CPAM-40在沼液添加比例为8%时,絮凝效果最好,板框压滤中试泥饼含水率最低,但仍无法达到深度脱水的要求。通过FeCl_(3)·6H_(2)O、PFS、PAC分别与CPAM-40的联合絮凝改性可明显降低板框压滤滤饼含水率,其中控制CPAM-40添加比例为8%,PAC添加比例为5%时,滤饼含水率低至48.6%,为最佳添加组合。通过降低板框压滤过程的开板压力可优化板框压滤效果,开板压力为0.3 MPa较为合适。

This article takes the dry anaerobic system biogas slurry as the research object,and analyzes the effects of ferric chloride(FeCl_(3)·6H_(2)O),polyferric sulfate(PFS),polyaluminum chloride(PAC),and cationic polyacrylamide(CPAM)coagulants with different ion degrees on the flocculation and dehydration of biogas slurry through small-scale experiments and plate and frame pressure filtration pilot tests.Research has shown that the use of CPAM-40 alone results in the best flocculation effect when the addition ratio of biogas slurry is 8%.The moisture content of the test mud cake in the plate and frame filter press is the lowest,but it still cannot meet the requirements of deep dehydration.The combined flocculation modification of FeCl_(3)·6H_(2)O,PFS,and PAC with CPAM-40 can significantly reduce the moisture content of the plate and frame filter cake.When the CPAM-40 addition ratio is controlled at 8%and the PAC addition ratio is 5%,the moisture content of the filter cake can be as low as 48.6%,which is the optimal addition combination.By reducing the plate opening pressure during the plate and frame pressure filtration process,the plate and frame pressure filtration effect can be optimized.A plate opening pressure of 0.3 MPa is more suitable.