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Study On Comprehensive Utilization Process Of Waste Fluid In The Production Of Caprolactam From Toluene

Posted on:2011-01-31Degree:MasterType:Thesis
Country:ChinaCandidate:H PengFull Text:PDF
GTID:2121330332463995Subject:Chemical Engineering
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The technology of the production of caprolactam from toluene in Shijiazhuang Chemical Fiber Company Ltd. is Italian SNIA's technology. Annual output of 5 million tons of waste fliud was discharged from the annual production of 5 million tons of caprolactam. The waste liquid generated by this process is a complex composition, with COD of 518 000 mg/L, NH3-N of 125.8 mg/L, pH value of 11, belonging to the high concentration of refractory organic wastewater which can not be directly discharged. Presently, high-temperature incineration the enterprise approach to has many disadvantages, such as high energy consumption, high operating costs, pluging the nozzle and lack of recycling valuable ingredients. According to these deficiencies, by direct distillation, azeotropic distillation and solvent extraction washing, the waste liquid is separated into water, salt and oil in this study. The qualitative and quantitative analysis, refining, refined and utilization of the separated salt were discussed, as well as the analysis and utilization of the oil by the establishment of reversed-phase ion-pair chromatography.Experimental studies showed that: the waste fluid was segregated into three parts with m(water): m(salt): m(oil)= 55:34:11 with m(toluene): m(benzene): m(waste) = 1:1:2, azeotropic temperature of 82℃, stirring speed 300 r/min, methanol for detergent and extraction, mixing washing for three times. The effluent water can be incorporated into the company's existing deal with drainage system, with COD of 1886 mg/L, NH3-N of 14.6 mg/L, pH of 9, which can maximize use of the existing facilities and reduce investment costs.Crude salt is brown in which Cyclohexyl carboxylic acid-sulphonic acid content is more than 90% and about 10% is unknown by HPLC methods. Through analysis of the process, the unknown may be organic material of amine. The purification of the salt is achieved by using hydrogen peroxide and activated carbon. The optimum condition are found :when m(activated carbon):m(hydrogen peroxide):m(the beginning of salt) = 0.50:0.75:15, oxidation temperature is 65℃, oxidation time is 10 min and adsorption time is 30 min. The purity of cyclohexane carboxylic acid-sulfonic acid was 98.5% and the yield reached 90.2%.Cyclohexane carboxylic acid-sulphonic acid causing the pro-electrophilic substitution, using sulfuric acid sulfonation process of the reverse reaction, H+ as an electrophilic reagent attacking the fat ring connected sulfosalicylic carbon atoms, containing sulfonic groups hydrolysis of organic matter and making sulfosalicylic off. The conditions are found: diluted hydrochloric acid at 150℃under the autoclave, the pressure of 0.35 Mpa, speed of 400 r/min. Cyclohexane carboxylic acid sulfonic acid made sulfonic acid off. The product was identified as cyclohexyl carboxylic acid by UV-Vis spectrophotometer, fourier transform infrared spectrometer, NMR and liquid chromatography. The product is raw materials of organic chemical and synthetic drugs intermediate, with broad application prospects. It can be export to create economic values.The main components of the oil and their relative contents were identified and determined by the reversed-phase ion-pair chromatography. The separation conditions are as follows: Agilent Eclipse XDB-C18 (4.6 mm×150 mm,5μm) as column, v(methanol): v (water) = 30:70 as mobile phase, 4 mmol/L tetrabutylammonium bromide as ion-pair reagent, 16 mmol/L of potassium dihydrogen phosphate as a buffer modifier, pH = 6, flow rate at 1 mL/min, UV detection wavelength of 220 nm, column temperature 25℃, injection volume at 20μL. The results of qualitative and quantitative analysis by the external standard method are as follow: w(caprolactam)=6.36%, w(cyclohexane carboxylic acid)=4.53%, w(cyclohexanol)=8.76%, w(cyclohexanone)=12.96%, w(phenol) =20.31%, w(cyclohexyl carboxylic acid-sulfonic acid)=0.25%. All of them can be recycled. The main technical indicators of the oil were determined. The results showed that the heat of combustion was 20 384 J/g, the viscosity of 30.78°E at 28℃, w(S)= 1.07%, flash point was 108.5℃, w(water)= 0.8%, w(mechanical impurities)= 0.09% and w(ash) = 0.08%, in accord with technical indicators of a furnace fuel oil (heavy oil). It can be used in boilers, industrial furnace, smelting furnace, burning furnace and so on, which has significant social, environmental and economic benefits.
Keywords/Search Tags:waste fluid of caprolactam, cyclohexane carboxylic acid-sulphonic acid, reversed phase ion-pair chromatography, fuel oil
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