| As an important oil agent in the tertiary phase, polyacrylamide is very important to increasing and stabilizing crude oil production. Meanwhile, polymer concentration has increased sharply in produced liquid and sewage treatment equipments are susceptible to harm. Consequently, it will be crucial to select an appropriate method to degradate polyacrylamide quickly.The main content of this research is around the process optimization of electrochemical degradation in oil recovery wastewater from polymer flooding. Aluminum and aluminum electrode were considered as anode materials in the optimization design. The influence of electrode plates interval、pairs of electrodes、 current intensity、processing time、ratio of area to volume、molecular weight of HHPAM on the electrochemical treatment was discussed in the research by analyzing viscosity reduction rate、oil degradation rate、turbidity removal rate. Through the measurement processes, optimum technological condition was used in the treatment, after that, water quality could reach the indexes for water injection.From the first chapter, as a kind of high molecular polymer, polyacrylamide’s type and application were discussed. Considered as a high-value-added fine chemical products, polyacrylamide have good efficiency of flocculation, it had been widely used in chemical industrial wastewater treatment、municipal sewage purification、enhanced the recovery ratio. Then oil displacement principle in the oil recovery process was discussed, at last the content and purpose of this research was introduced.From the second chapter, testing methods of polymer concentration in polymer flooding sewage were introduced such as turbidimetric、ultraviolet spectrophotometry、 Uzziah’s viscosity method、Starch-the iodine cadmium method. From research, Uzziah’s viscosity method would be the most propriate way to adjust the reality of offshore oilfield because with it, samples could be analyzed at a large scale and at a short time. According to many scholars, a lot of technologies were used to degradated HHPAM in the sewage, such as mechanical methods、photocatalytic oxidation、ultrasonic wave、 chemical reagent、electrochemistry method、biological strains culture technology. From the methods mentioned above, selected a technology with low cost、harmfullness、 environment、high-efficient to degradate HHPAM in the polymer flooding sewage is very important on the offshore oilfield platform.From the third chapter, the theory of electrochemical degradation was introduced, through it the process of electrocoagulation in the sewage treatment was stated. In another word, impurity of polymer flooding sewage was wiped out by oxidizing and reduction reaction、electrocoagulation、electroflotation. And then the influence of the ionic composition、temperature、pH value of JZ9-3formation brines and mechanical shear rate on the viscosity reduction rate was discussed. Based on such study, the influence of electrode materials、current intensity、electrode plates interval、processing time、ratio of area to volume、molecular weight on the degradation of HHPAM was analyzed. From these factors, current intensity、electrode plates interval、processing time and ratio of area to volume were chosed in orthogonal test. The degradation ratio of HHPAM could reach to98.12%while electrode plates interval was6cm, ratio of area to volume was8/40, processing time was20min, current intensity was4A. From the analyze of treatment effect、energy consumption、electrode’s life span、the electrode Ioss、actual consumption from energy meter while electrocoagulation in JZ9-3sewage by using static and dynamic methods with reference to optimum technological condition.In the forth chapter, with optimum technological conditions, different equipment units were held in CH-1multifunctional water treatment device. Concrete steps can be identified as follows:with polymer concentration200mg/L, oil content198.2mg/L, solid suspended content200mg/L of simulation water sample prepared. Under the condition such as weather was55℃, residence time was20min in the grease trap, ratio of plate area to volume was8/53, current intensity was3A, kept the process runs stably and then analyze the water quality, particle size of water sample before filter was distributed from18.5to248.9u m. It can be founded that particle size of water from one stage filtered mostly distributed from0.687to7.78μ m. From the result of this research, it can be inferred that the filter effect was evident in the treatment process. While considering on the viscosity reduction rate was only55%, the effect could be improved if only divided electro-grease trap into two pieces and extend the processing time.With the same method to prepare simulation water with polymer content300mg/L, oil content327.4mg/L, solid suspended content200mg/L. Under the condition such as weather was55℃, residence time was25min in the grease trap, ratio of plate area to volume was8/100, current intensity was3A, kept the process runs stably and then analyze the water quality, its oil removal rate was86.9%, viscosity reduction rate was72.6%, particle size of water sample before filter was distributed from15.5to352u m. It can be founded that particle size of water from one stage filtered mostly distributed from0.97to6.54u m. It can be concluded that water quality had been improved after alter the related technological parameter.Before continuous treatment of JZ9-3sewage, added200mg/L doze of polymer because of high degree of water absorbency after a long store time. Under the condition that residence time was25min in the grease trap, ratio of plate area to volume was8/60, current intensity was3A, electrocoagulation time was17min. kept the process runs stably and then analyze the water quality, its oil removal rate was91.7%, viscosity reduction rate was also91.7%, particle size of water sample before filter was distributed from3.27to104μm. And particle size of water from one stage filtered distributed from0.97to55μ m, particle size of water from two stage filtered are all less than2.75u m.After that treated water would reached to control standards in the round, expected experiment purpose would be realized.The main content of chaper five is brief summary on the research. Detection of content of HPAM would be influenced by interference factor such as pH value of solution、total salinity、oil content、degree of hydrolysis of HPAM. Uzziah’s viscosity method would be the most propriate way to adjust the reality of offshore oilfield. And electrochemical method was a suitable way to degradate HPAM. The degradation rate was related to electrode materials、numbers of electrode、average molecular weight of HPAM、current intensity、processing time、electrode plates interval、ratio of area to volume. After orthogonal test, appropriate technological parameter was selected to be used in continuous treatment of simulated polymer solution and JZ9-3sewage. From the research, water quality was improved envidently.To sum up in conclusion, detailed study on the effectiveness of polymer flooding sewage by using electrochemical degradation method, factors influence on degradation rate, select appropriate conditions through orthogonal test. And then to enhance the effectiveness of HPAM degradation by altering the existing process equipment. Under suitable conditions, there was a envident improvement in the water quality through optimal processing parameters. While it reached to the expected effect, the performance of processing equipment and its energy consumption was evaluated in the lab. |
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