Analysis of typical pollutants and its removal characteristics in the pretreatment of coking wastewater

doi:10.16085/j.issn.1000-6613.2017-0310

Abstract

Abstract: Coking wastewater contains toxic refractory compounds in high loads,distributed between liquid and suspended solids. The pretreatment including gravity sedimentation,ammonia stripping/phenol extraction,coagulation/air floatation and ozonation was applied prior to biological treatment providing its effective performance. The removal of characteristic pollutants was studied in each pretreatment process. The results showed that 56.05% of suspended solids and 46.54% oil content were removed in 90min gravity sedimentation. Ammonia was stripped for 50min,and phenol was extracted using mixture of tributyl phosphate with 30% kerosene at pH=9,T=30℃,R=1∶4,n=3. Ammonia and phenol were recovered for 69.85% and 76.02%,respectively. At the FeSO₄dosage of 1500mg/L and initial pH=9,coagulation/air floatation removed sulfide,cyanide and ammonia for 89.93%,60.68% and 2.95%,respectively. At the concentration of gaseous ozone 14mg/L±1mg/L and initial pH＝10,sulfide,cyanide and ammonia were degraded as a result of 80min ozonation for 94.92%,91.05% and 47.26%,respectively. The results obtained in the study may serve the optimization of the pretreatment process,targeting the purification performance and the economic efficiency with the separation of phases,the recovery of chemical products and the transformation of toxic pollutants.

Key words: coking, gravity sedimentation, ammonia stripping, phenol extraction, coagulation, oxidation

摘要： 焦化废水是典型的有毒/难降解工业有机废水，表现出高浓度、多相、多组分共存的性质，需对其进行预处理以保证后续生物处理系统高效稳定的运行。本文结合实验数据与工程实例，重点分析了重力沉降、蒸氨/脱酚、混凝/气浮、臭氧氧化单元工艺作为预处理技术对焦化废水原水中特征污染物的分离去除情况。研究发现：经过90min重力沉降，56.05%的悬浮颗粒和46.54%的油分得到分离；接着，将初始pH=10的废水蒸氨50min后，在pH=9、T=30℃、R=1∶4、n=3的条件下采用磷酸三丁酯-30%煤油进行萃取脱酚，氨氮和苯酚的去除率分别为69.85%和76.02%；随后，在FeSO₄投加量为1500mg/L、初始pH=9的混凝/气浮反应中，硫化物、氰化物以及氨氮的去除率分别为89.93%、60.68%和2.95%；最后，在臭氧浓度为14mg/L±1mg/L、初始pH=10、反应时间为80min的臭氧氧化反应中，硫化物、氰化物以及氨氮的去除率分别达到94.92%、91.05%和47.26%。上述研究结果对于焦化废水预处理工艺的进一步优化具有指导意义，同时认为，这类废水预处理技术的优化与应用需要综合考虑相分离、产品分离和有毒物质的转化这3个层面有效性与经济性的结合。

关键词: 焦化, 重力沉降, 蒸氨, 脱酚, 混凝, 氧化

CLC Number:

X703

WU Hengping, WEI Chaohai, REN Yuan, WU Jinhua, LIU Ming, WEI Cong. Analysis of typical pollutants and its removal characteristics in the pretreatment of coking wastewater[J]. Chemical Industry and Engineering Progress, 2017, 36(10): 3911-3920.

武恒平, 韦朝海, 任源, 吴锦华, 刘明, 韦聪. 焦化废水预处理及其特征污染物的变化分析[J]. 化工进展, 2017, 36(10): 3911-3920.

References

[1] 任源,韦朝海,吴超飞,等.焦化废水水质组成及其环境学与生物学特性分析[J].环境科学学报,2007,27(7):1094-1100.REN Y,WEI C H,WU C F,et al.Environmental and biological characteristic of coking wastewater[J].Acta Scientiae Cirumstantiae,2007,27(7):1094-1100.
[2] 韦朝海,朱家亮,吴超飞,等.焦化行业废水水质变化影响因素及污染控制[J].化工进展,2011,30(1):225-232.WEI C H,ZHU J L,WU C F,et al.Influence factors of coking wastewater components and pollution control[J].Chemical Industry and Engineering Progress,2011,30(1):225-232.
[3] 韦朝海,廖建波,胡芸.煤的基本化工过程与污染特征分析[J].化工进展,2016,35(6):1875-1833.WEI C H,LIAO J B,HU Y.Basic coal chemical processes and their pollution characteristics[J].Chemical Industry and Engineering Progress,2016,35(6):1875-1833.
[4] 韦朝海,贺明和,任源,等.焦化废水污染特征及其控制过程与策略分析[J].环境科学学报,2007,27(7):1083-1093.WEI C H,HE M H,REN Y,et al.Pollution characteristic of coking wastewater and control strategies:biological treatment process and technology[J].Acta Scientiae Cirumstantiae,2007,27(7):1083-1093.
[5] 韦朝海.煤化工中焦化废水的污染、控制原理与技术应用[J].环境化学,2012,31(10):1465-1472.WEI C H.Pollution control principles and technology applications in the treatment of coking wastewater from coal chemical industy[J].Environmental Chemistry,2012,31(10):1465-1472.
[6] 魏复盛.水和废水监测分析方法[M].4版.北京:中国环境科学出版社,2002.WEI F S.Methods for monitoring and analysis of water and wastewater[M].4^th ed.Beijing:Chinese Environmental Science Press,2002.
[7] 曹睿,付国垒,严超宇,等.我国煤化工的产业格局以及应对低碳经济的发展策略[J].化工进展,2010,29(s1):269-277.CAO R,FU G L,YAN C Y,et al.The industry pattern of China coal chemical industry and the strategies for low carbon economy[J].Chemical Industry and Engineering Progress,2010,29(s1):269-277.
[8] 冯大春.用于煤气化废水预处理的新流程开发与模拟[J].化工进展,2011,30(4):901-907.FENG D C.Design and simulation of a novel process for coal gasification wastewater pretreatment[J].Chemical Industry and Engineering Progress,2011,30(4):901-907.
[9] 钱宇,周志远,陈赟,等.煤气化废水酚氨分离回收系统的流程改造和工业实施[J].化工学报,2010,61(7):1821-1828.QIAN Y,ZHOU Z Y,CHEN Y,et al.Process retrofit and industrial implementation of phenol and ammonia recovery from coal gasification wastewater[J].Journal of Chemical Industry and Engineering(China),2010,61(7):1821-1828.
[10] 姚晓琰.焦化厂蒸氨工艺的实验研究及节能工艺的探索[D].天津:天津大学,2014.YAO X Y.Research on the process of steam ammonia distillation in coke plant and exploration of energy saving process[D].Tianjin:Tianjin University,2014.
[11] 章莉娟,冯建中,杨楚芬,等.煤气化废水萃取脱酚工艺研究[J].环境化学,2006,25(4):488-490.ZHANG L J,FENG J Z,YANG C F,et al.Extratcion recovery process of phenols from coal gasification wastewater[J].Environmental Chemistry,2006,25(4):488-490.
[12] 张红涛,刘永军,张云鹏,等.高酚焦化废水萃取脱酚预处理[J].环境工程学报,2013,7(11):4427-4430.ZHANG H T,LIU Y J,ZHANG Y P,et al.Pretreatment of coking wastewater containing phenols by extraction method[J].Chinese Journal of Environmental Engineering,2013,7(11):4427-4430.
[13] 钱宇,杨思宇,马东辉,等.煤气化高浓酚氨废水处理技术研究进展[J].化工进展,2016,35(6):1884-1893.QIAN Y,YANG S Y,MA D H,et al.Research advances in treatment of coal gasification wastewater with high phenol and ammonia[J].Chemical Industry and Engineering Progress,2016,35(6):1884-1893.
[14] 冯惠生,陈文峰,任洪东,等.苯酚羟化液多级萃取分离及磷酸三丁酯配合萃取过程[J].化工进展,2008,27(10):1618-1623.FENG H S,CHEN W F,REN H D,et al.Separation of phenol hydroxylation mixture by multi stage extraction and complexation extraction by hydroxylation with tributyl phosphate[J].Chemical Industry and Engineering Progress,2008,27(10):1618-1623.
[15] 雷勇.甲基叔丁基醚萃取煤气化含酚废水体系液液相平衡和流程模拟研究[D].广州:华南理工大学,2014.LEI Y.Study on liquid liquid equilibria and process simulation of the extraction system to remove phenols from coal gasification with MTBE[D].Guangzhou:South China University of Technology,2014.
[16] 张志辉,酆婧轩,郑天龙,等.混凝-微气泡气浮法预处理油田采出废液[J].水处理技术,2014,40(5):103-107.ZHANG Z H,FENG J X,ZHENG T L,et al.Pretreatment of oilfield production wastewater using coagulation/microbubble air floatation technology[J].Technology of Water Treatment,2014,40(5):103-107.
[17] 李湘溪,吴超飞,吴海珍,等.焦化废水处理过程中盐分变化及其影响因素[J].化工进展,2016,35(11):3690-3700.LI X X,WU C F,WU H Z,et al.The changes of salt and its influencing factors during coking wastewater treatment[J].Chemical Industry and Engineering Progress,2016,35(11):3690-3700.
[18] YU X B,XU R H,WEI C H,et al.Removal of cyanide compounds from coking wastewater by ferrous sulfate:improvement of biodegradability[J].Journal of Hazardous Materials,2016,302:468-474.
[19] LIN C,LIAO J B,WEI C H.Modeling and optimization of the coagulation of highly concentrated coking wastewater by ferrous sulfate using a response surface methodology[J].Desalination and Water Treatment,2015,56(12):3334-3345.
[20] 吴锦华,谭雪云,江燕斌,等.煤化工废水硫酸亚铁混凝预处理及可生化性提高研究[J].广东化工,2016,43(23):5-7.WU J H,TAN X Y,JIANG Y B,et al.Study of recalcitrant compounds removal and biodegradability improvement of coal chemical engineering wastewater by coagulation pretreatment with ferrous sulfate as coagulant[J].Guangdong Chemical Industry,2016,43(23):5-7.
[21] 洪浩峰,潘湛昌,许磊,等.臭氧催化氧化处理苯酚废水研究[J].环境科学与技术,2010,33(6E):301-304.HONG H F,PAN Z C,XU L,et al.Degradation of aqueous phenol by catalytic ozonation[J].Environmental Science & Technology,2010,33(6E):301-304.
[22] 白小霞,杨庆,丁昀,等.催化臭氧氧化处理难降解石化废水技术的研究进展[J].化工进展,2016,35(1):263-268.BAI X X,YANG Q,DING Y,et al.Research progress of catalytic ozonation process to treat refractory petrochemical wastewater[J].Chemical Industry and Engineering Progress,2016,35(1):263-268.
[23] 易欣怡.焦化废水生物工艺中含氮化合物的转化及臭氧选择性氧化过程分析[D].广州:华南理工大学,2014.YI X Y.Transformation of nitrogen compounds in coking wastewater during biological treatment process and ozone selective oxidation process analysis[D].Guangzhou:South China University of Technology,2014.