摘要
针对页岩气开采过程中产生的非常规压裂返排液具有高粘度、高COD及高稳定性的特点,以Fe(NO3)3和Ca(Cl O)2为原料,采用化学湿法中的两步法合成了一种绿色氧化剂K2Fe O4,并对合成出的K2Fe O4进行了定量分析,得到合成的高铁酸钾产率为67.63%,纯度为93.41%。采用X衍射、红外光谱、扫描电镜及X衍射能谱,对合成的K2Fe O4进行了表征。将K2Fe O4作为某气田页岩气压裂返排液的高效破胶剂,并对影响破胶效果的因素进行了分析。确定了K2Fe O4的加量为3 000 mg/L,体系p H为11.0及反应时间为40 min的最优条件,在最优条件下,得到出水的粘度为1.4 m Pa·s,其COD、SS和色度的去除率分别为59.1%、93.3%和88.9%。通过红外光谱和扫描电镜进行了微观观察,对K2Fe O4氧化非常规压裂返排液中主要成分胍胶的过程进行了机理分析。研究还发现,K2Fe O4在还原分解后,具有比单一铁离子更强的混凝效果。因此,K2Fe O4的应用对页岩气压裂返排液的处理有深远的影响。
focused on the resulting problem of unconventional fracturing flow-back fluid of shale gas production such as high viscosity,high COD and high stability,a green and efficient gel breaker K2 Fe O4was synthesized by a two-step wet process with Fe( NO3)3and Ca( Cl O)2as initial material. Quantitative analysis shows the productivity of K2 Fe O4is 67. 63% and the corresponding purity is 93. 41%. The molecular composition and molecular structure were examined by XRD,FT-IR and SEM-EDS. The optimal dosage of K2 Fe O4,p H,and reaction time are 3 000 mg / L,11. 0,and 40 min,respectively. With the conditions mentioned above,viscosity of flow-back fluid reduced to 1. 4 m Pa · s,while removal rates of COD,SS and chromaticity were 59. 1%,93. 3%,and88. 9%,respectively. Besides,the mechanism of gel breaking was also studied in this work. After deoxidation and decomposition,coagulation effect of K2 Fe O4is better than single iron ions.
出处
《环境工程学报》
CAS
CSCD
北大核心
2015年第4期1869-1874,共6页
Chinese Journal of Environmental Engineering
关键词
页岩气
压裂返排液
高铁酸钾
破胶剂
shale gas
fracturing flow-back fluid
K2FeO4
gel breaker
