Ultrasonic Space Generation Catalytic Pretreatment Of Coking Wastewater

Coking coal process wastewater is produced in the process of coal-coke, gas purification and coking product recovery, which affected by the factors of the nature of coal, coking process and coking product recovery and so on. Its composition is complex, it has a high concentration of NH3-N and POPs, and water quality and quantity is changes large. However, the consequent of traditional biochemical process for ammonia nitrogen and COD removal is not ideal, it is hard to make the effluent steadily reach the discharging standard. Thus it is important to search for a primary processing method to decompose inert organic which is toxic and difficult governance.The research on ultrasonic chemistry began in 1927, when many chemical reactions were observed in the ultrasonic field. In recent years, the study of sound chemistry focuses on the use of ultrasonic energy to solve the water pollution problem, especially in the removal of toxic wastewater, hazardous organic compounds. For many pollutants, the process of ultrasonic wave has a huge advantage in completely destroying or converting for these organisms, rather than simply transferring from one medium to another.This paper on the basis of summarized the research on coking wastewater treatment technology domestic and oversea, put forward the research purpose. Selected Kunming iron and steel corporation Anning coking plant regulating reservoir raw water, Dabanqiao town coal coking corporation limited separation tank raw water as the test subjects, according to the phonochemistry correlation calculation, use the ultrasonic reactor which designed and manufactured autonomously pretreat the coking wastewater raw water. The ultrasonic cavitation degradation effect of ammonia nitrogen and CODCr, and the reaction dynamics of ammonia nitrogen degradation was studied. Before and after processing, using HPLC analysis the main organic component in coking wastewater. Discussed the effect of various factors on the degradation of ammonia nitrogen and CODCr, calculated the dispose cost of the reactor, the specific are as follows:(1) The ultrasonic cavitation has varying degree of degradation on ammonia nitrogen and CODCr in coking wastewater; the ultrasonic power, ultrasonic frequency, reaction liquid initial pH value, initial concentration are the influence factor of degradation effect, the degradation rate of ammonia nitrogen and ultrasonic power were positively correlated; in low frequency range, the degradation rate of ammonia nitrogen and ultrasonic requency were positively correlated; neutral alkaline pH value is most beneficial to the degradation of ammonia and CODCr; the degradation rate of ammonia nitrogen decreased with the increase of initial concentration. The variation trend of CODCr degradation rate has no remarkable correlation with influence factor, according to the GC-MS analysis result, speculate the ultrasonic cavitation effect only changed the structure of organics, it has not be completely degraded to the small molecules.(2) Aeration has evident influence on the degradation effect of ammonia nitrogen and CODCr in coking wastewater. Continuous aeration is conducive to ultrasonic degradation, aeration itself has no obvious degradation effect to ammonia nitrogen and CODCr. Ultrasonic cavitation degradation organic matters in coking wastewater, ·OH free radical oxidation reaction is the main reaction; so aeration can increase the dissolved oxygen content in reaction liquid, it is helpful to generate more ·OH free radical in cavitation bubbles, thereby promote the degradation of COCr.(3) In the case of continuous aeration, ultrasonic-ultraviolet irradiation for 180 min, the degradation rate of ammonia nitrogen and CODCr respectively reached 34.5%,30.7%. Ultrasonic-ultraviolet irradiation degradation effect of ammonia nitrogen and CODCr is slightly superior to ultrasound alone, and ultraviolet irradiation alone has no significant degradation effect of ammonia nitrogen and CODCr. According to the HPLC analysis result, ultrasonic cavitation has good degradation effect on pyridine, phenol, indoles and other organic material.(4) The ultrasonic cavitation degradation reaction of ammonia nitrogen in obedience to the second-order reaction dynamics, and the high concentrations apparent rate constant K is greater than the low concentration. Shows that ultrasonic cavitation degradation efficiency of high concentration ammonia nitrogen is higher.(5) The designed processing capacity of ultrasonic reaction is 5L, outfit the 300w power ultrasonic generator,250w power gas ring blower,175w power UV high pressure mercury lamp. Depending on the calculations, ultrasonic alone experiment one time needs energy charge 0.36 vuan; continous aeration, ultrasonic-ultraviolet irradiation experiment one time needs energy charge 0.87 yuan. The processing cost is too high.