Treatment of Spent Caustic Effluent of Oil Refinery with Catalytic Oxidation and Optimization of Relevant Parameters using Response Surface Methodology

Document Type : ORIGINAL RESEARCH PAPER

Authors

1 islamic azad university ,environmental department

2 Research institute of petroleum industry ,Refining technology department ,Assistant professor of Chemical Engineering

3 azad Islamic university ,Environment department

4 Islamic Azad University of Tabriz,environemnt department

5 Research institute of petroleum industry

10.22034/ap.2021.1923341.1093

Abstract

Caustic soda is a substance used for sweetening hydrocarbon products in oil refinery, gas and petrochemical units. The caustic soda-generated salts are increasingly formed during the process of removing impurities like mercaptans, sulfides and nitrates, which finally leave process system through spent caustic discharge. Spent caustic discharge into environment is prohibited due to the presence of compounds like organic and toxic substances, sulfide salts, mercaptans as well as high chemical oxygen demand (COD), emphasizing the need to treat such effluents. The present study aimed to apply catalytic wet air oxidation method for treatment of spent caustic effluent from Bandar Abbas oil refinery and to optimize related parameters. Experimental processes were performed in a 500-ml batch reactor. Catalyst concentration, residence time and stoichiometric air flow parameters were optimized by Box-Behnken design. Based on the results, optimal conditions for this process were the catalyst concentration of 123 ppm, the residence time of 3 h and the stoichiometric air flow of 4.1 l/h, with a maximum reduction of spent caustic COD of 42.2%. The results of optimization experiments were analyzed by Design Expert 11 software, the results of which documented that the three mentioned parameters had the greatest effect on reducing spent caustic COD. Prolonging residence time had no significant effect on COD removal. Polynomial equation based on the three mentioned variables was presented to predict the spent caustic COD changes. In this treatment method, in addition to a significant reduction in COD, the available toxic substances also reached less than 1 ppm.

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Main Subjects


Ahmadpour A, Haghighi Asl A, Fallah N, Behjomanesh M, Ghasemi M, (2016) Treatment of Spent Caustic Effluent of Oil Industry Olefin Units. 6th Conference on Energy and Environment. 22 Dec, Tehran, Iran: 1-18.
Alishiri A, Fataei, E, Ranjbar Baranloo H, (2020) The effects of nutrients and folic acid on the biological treatment of petrochemical wastewater , Journal of Advances in Environmental health research, 8(3): 206-214.
Bahrami F(2016) Optimization of electrocoagulation process of waste spent caustic by iron electrode to reduce COD using experimental design. MD Dissertation, Shiraz University
Bakhshandeh M (2017) Caustic wastewater treatment of shazand petrochemical olefin unit by electro-fenton technique. MD Dissertation, Arak University 
Bhargava S, Tardio J, Prasad J, Foger K, (2006) Wet Oxidation and Catalytic Wet Oxidation. Industrial & Engineering Chemistry Research. 45(4): 1221-1258.
Box G. E. P, Wilson K. B, (1992) On the Experimental Attainment of Optimum Conditions. Breakthroughs in Statistics: 270–310.
Claude E.E, (1998) Wet air oxidation of refinery spent caustic, Environmental Progress & Sustainable Energy. 17(1): 28–30.
Chen C, Cheng T, (2013) Wet Air Oxidation and Catalytic Wet Air Oxidation for Refinery Spent Caustic Degradation. Journal- Chemical Society of Pakistan. 35(2): 243-249.
De Angelo D.J, Wilhelmi A.R, (1983) Wet air oxidation of spent caustic liquors. Chemical Engineering Progress. 79: 45-56.
Debellefontaine H, Chakchouk M, Foussard J.N, Tissot  D, Striolo P, (1996) Treatment of organic aqueous wastes: Wet air oxidation and wet peroxide oxidation. Environmental Pollution. 92(2): 155–164.
Esmaeilzadeha, H, Fataei E, Saadati H., (2020) NH3 Removal from Sour Water by Clinoptilolite Zeolite: A Case Study of Tabriz Refinery. Chemical Methodologies, 4(2020) 754-773
Hawari A, Ramadan H, Abu-Reesh I, Ouederni M, ( 2015) A comparative study of the treatment of ethylene plant spent caustic by neutralization and classical and advanced oxidation. Journal of Environmental Management. 151: 105-112.
Heponiemi A (2015) Catalytic wet air oxidation of industrial wastewaters, Oxidation of bisphenol A over cerium supported metal catalysts. MD Dissertation, University of Oulu
Hii K, Baroutian S, Parthasarathy R, Gapes D.J, and Eshtiaghi N, (2014) A Review of Wet Air Oxidation and Thermal Hydrolysis Technologies in Sludge Treatment. Bioresource Technology. 155: 289-299.
Kumfer B, Felch C, Maugans C, (2010) Wet Air Oxidation Treatment of Spent Caustic in Petroleum Refineries. The National Petroleum Refiners Association Conference. 21-23 Mar. Phoenix, AZ, USA. 49-67.
Karimi A, Fatehifar E, Alizadeh R,  Ahadzadeh I, (2016) Regeneration and treatment of sulfidic spent caustic using analytic hierarchy process. Environmental Health Engineering and Management Journal. 4(3): 203–208.
Karimi A, Fatehifar E, Alizadeh R, Ahadzadeh I, (2017) Regeneration of Spent Caustic of Olefin Unit in a Bubble Column Reactor: Treatment and Recovery Optimization. Environmental Progress & Sustainable Energy. 36(2): 341-347.
Karimi A, Delsalem R (2017) Investigation of spent caustic effluent treatment using statistical analysis. 4th National Conference on New Research in Chemistry and Chemical Engineering. 28 sep, Tehran, Iran: 1-9.
Luan M, Jing G, Piao Y, Liu D, Jin L, (2012) Treatment of refractory organic pollutants in industrial wastewater by wet air oxidation. Arabian Journal of Chemistry. 1-8.
Levec J, Pintar A, (2007) Catalytic wet-air oxidation processes: a review. Catalysis Today 124(3):172–184.
Luck F, (1999) Wet air oxidation: past, present and future. Catalysis Today. 53(1): 81-91.
Maugans C, Howdeshell M, De Haan S, (2010) Update: Spent caustic treatment, Hydrocarbon Processing, 66 (Special Report).
Mohammadizadeh Z, (2018) Spent Caustic Treatment by Catalytical Oxidation and Optimization of Parameters. MD Dissertation, Sahand University of Technology
Mohsenzadeh M, Mirbagheri S.A, (2018) Advanced photocatalytic oxidation in treatment of petrochemical industry effluent. 5th Conference on Applied Research in Civil Engineering, Architecture and Management. 3 Jun, K.N.Toosi University of Technology, Tehran, Iran. 1-13
Montes R. E, Gomez F.A., Hanrahan G, (2008) Response surface examination of the relationship between experimental conditions and product distribution in electrophoretically mediated microanalysis. Electrophoresis. 29(2): 375–380.
Mortazavian A, (2017) Industrial Waste Water treatment via Oxidation processes. MD Dissertation. Chemistry and Chemical Engineering Research Center of Iran.
Naizy R, (2008) Economic analysis for wet oxidation processes for the treatment of mixed refinery spent caustic. Environmental Progress & Sustainable Energy. 27(3): 295–301.
Rathore V, Gupta S, Thorat T, Rao P. V. C, Choudary N. V.,  Biju G (2011) Catalytic oxidation of spent caustic.  Www.digitalrefining.com/article/1000391
Shih-Hsiung S, Hung-Shan W, (2001) Treatment of olefin plant spent caustic by combination of neutralization and Fenton reaction. Water Research. 35(8): 2017–2021.