湿法同时脱硫脱硝特性及吸收液制过硫酸铵的实验研究

发布时间：2018-03-11 05:12

本文选题：电流效率　切入点：硫氰酸铵　出处：《东南大学》2015年硕士论文　论文类型：学位论文

【摘要】：尿素／氨混合溶液同时脱硫脱硝工艺具有非常高的脱硫效率和较高的脱硝效率,且其循环吸收液中硫酸铵的含量高达82%。采用电化学方法将循环吸收液中的硫酸铵制备成具有高附加值的过硫酸铵,是尿素／氨混合溶液同时脱硫脱硝工艺资源化回收利用的具有发展前景的研究课题和方向。本文在自制的电解实验装置上,阴极材料分别采用铅板和未见于报道的钛板,对硫酸铵电解过程中工艺参数(电解电压、反应物浓度、添加剂、反应时间等)的影响特性进行了实验研究,研究发现钛板能够在低于铅板的电解工艺参数下获得较高的电流效率和转化率。分别在钛板和铅板的最佳电解条件下进行电解,发现采用钛板4h后电流效率为60.16%,而铅板的电流效率仅为52.17%。上述研究结果表明,钛板是一种可替代铅板的新型阴极材料。此外,考虑到尿素／氨混合溶液同时脱硫脱硝工艺循环吸收液中的成分,本文以钛板为阴极板,筛选了尿素、氯化铵、聚磷酸铵和硫氰酸铵及其交叉配比的混合添加剂进行电解性能的实验研究。实验发现,四种单一添加剂对电解的促进作用依次为硫氰酸铵尿素聚磷酸铵氯化铵。采用动态法进行性能对比发现,聚磷酸铵可以缓解电流效率随时间的下降；采用质量浓度0.1%的尿素与质量浓度0.25%的聚磷酸铵配比的混合添加剂对电解的促进效果最好,其对应的电流效率达到86.77%,优于二者任意单一添加剂对电解的促进作用。由于电解过硫酸铵结晶余液中含有少量过硫酸铵,其对脱硝具有较大的促进作用。基于对尿素／氨混合溶液同时脱硫脱硝工艺吸收液电解制过硫酸铵结晶余液的绿色循环经济利用的考量,本文开展了尿素／氨混合溶液同时脱硫脱硝工艺吸收液电解制过硫酸铵结晶余液循环脱硝的实验研究。同时,由于氨基湿法烟气脱硫效率已经高达97%以上,而SO2对脱硝过程的影响主要体现在脱硫中间产物(NH4)2SO3上。因此,本文对电解硫酸铵的产物(过硫酸铵)和电解阳极添加剂(硫氰酸铵和聚磷酸铵),以及它们与常用湿法脱硝添加剂(二乙醇胺、三乙醇胺)进行配比的混合添加剂在亚硫酸铵／尿素溶液湿法脱硝性能方面进行了实验研究。实验发现,过硫酸铵的脱硝效果比硫氰酸铵的脱硝效果好。过硫酸铵是通过对NO的氧化来促进脱硝的；而硫氰酸铵是通过氧气对自身的的氧化作用促进脱硝过程的,且过量添加不利于脱硝过程,还会污染环境。因此,本文认为硫氰酸铵不适合作为尿素／氨混合溶液同时脱硫脱硝工艺吸收液电解法制过硫酸铵工艺和湿法脱硝过程的添加剂。过硫酸铵与二乙醇胺和三乙醇胺配比组成的混合添加剂对脱硝有明显的促进作用,但二乙醇胺与三乙醇胺的价格高,不利于降低脱硝系统成本。由于过硫酸铵和聚磷酸铵组成的混合添加剂对脱硝效率的促进作用优于二者任意单一添加剂,在质量浓度0.02%的聚磷酸铵中添加剂质量浓度0.05%过硫酸铵,30min内的平均脱硝效率达到51%。因此,本文认为将尿素和聚磷酸铵作为尿素／氨混合溶液同时脱硫脱硝工艺吸收液电解法制过硫酸铵工艺的添加剂,将过硫酸铵和聚磷酸铵作为尿素／氨混合溶液湿法脱硝工艺的添加剂是经济、绿色的,具有较高的工程应用前景和学术研究价值。
[Abstract]:Simultaneous desulfurization and denitration efficiency of urea / ammonia mixed solution denitrification process has very high desulfurization efficiency and higher, and the content of ammonium sulfate solution in the absorption cycle up to 82%. by electrochemical method in circulating absorption liquid of ammonium sulfate was prepared with high added value of ammonium persulfate, is off topic and direction denitrification process resource recycling with the development of future study on simultaneous desulfurization and ammonia / urea mixed solution. The electrolysis of self-made experimental device, titanium plate cathode materials were used and it has not been found in the report, the ammonium sulfate electrolysis process parameters (voltage, concentration of reactants, additives, reaction time etc.) effect was investigated, the study found that titanium plate can obtain higher current efficiency and conversion rate in the electrolytic process parameters under the solution conditions. It is lower than that in the best electric titanium plate and lead respectively. By electrolysis, using titanium plate after 4h, the current efficiency is 60.16%, and the current efficiency of it is only 52.17%. the results of the study show that titanium plate is a new type of cathode material can replace it. In addition, taking into account the denitrification process in circulating absorption liquid urea / ammonia desulfurization and composition of mixed solution, this paper titanium plate as the cathode plate, the screening of urea, ammonium chloride, experimental study of mixed additives of ammonium polyphosphate and ammonium thiocyanate and cross ratio of electrolytic performance. The experimental results showed that, four kinds of single additives on electrolytic role in ammonium thiocyanate poly urea ammonium phosphate ammonium chloride. The performance comparison with dynamic method ammonium polyphosphate, can alleviate the current efficiency with time decreased by 0.1%; the concentration of urea and concentration of 0.25% poly ammonium phosphate ratio of mixed additives on electrolytic effect best, the The current efficiency reached 86.77%, two better than any single additives on electrolytic role. Because electrolyte crystallization of ammonium sulfate in the raffinate containing a small amount of ammonium persulfate, has a greater role in promoting denitrification. The urea / ammonia mixed solution of simultaneous desulfurization and denitrification process of absorption liquid electrolysis preparation of ammonium persulfate over crystallization the green liquid recycling based on the consideration, this paper carried out the urea / ammonia mixture experimental study on simultaneous desulfurization and denitrification process of absorption liquid electrolysis preparation of ammonium persulfate crystallization more than liquid circulation denitration. At the same time, the desulfurization efficiency of wet flue gas - has reached more than 97%, while the effect of SO2 on denitration process mainly reflected in the desulfurization of intermediate product (NH4) 2SO3. Therefore, the product of electrolysis of ammonium sulfate (ammonium persulfate) and electrolyte additives (ammonium thiocyanate and ammonium polyphosphate), and their common wet denitration Tim With the agent (two ethanol, triethanolamine) was studied in mixed additive ratio denitrification performance in ammonium sulfite / urea solution wet. Experiments showed that the denitrification effect of ammonium persulfate than denitrification effect of ammonium thiocyanate. The ammonium persulfate is through the oxygen of the NO to promote off the nitrate and ammonium thiocyanate; through oxidation of oxygen to promote its denitration process, and the excessive addition is not conducive to the denitrification process, but also pollute the environment. Therefore, this paper thinks that ammonium thiocyanate is not suitable as urea / ammonia mixed solution of simultaneous desulfurization and denitrification process of absorption liquid by electrolysis process and ammonium persulfate wet Denitration Process additives. Mixed additives of ammonium persulfate and two ethanol amine and triethanolamine composition has obvious promoting effect on denitrification, but two ethanol with triethanolamine price is high, is not conducive to reducing denitration system Cost. Because the mixed additives of ammonium persulfate and ammonium polyphosphate on denitration efficiency promoting effect is better than the two in any single additive concentration of 0.02% poly 0.05% additive concentration of ammonium phosphate in ammonium persulfate, 30min average denitration efficiency reached 51%. therefore, the urea and ammonium polyphosphate at the same time as urea / ammonia mixed solution desulfurization additive denitrification process of absorption liquid by electrolysis process of ammonium persulfate, the ammonium persulfate and ammonium polyphosphate as additives for urea / ammonia mixed solution wet denitration technology is economic, green, value engineering application and academic research is very high.

【学位授予单位】：东南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X773

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