The Synthesis Of New Organic Amine Desulfurization Agent And Application Research

With the increasing use of coal and fossil fuels, the harm caused by sulfurdioxide gas producing by the fuels on the atmospheric environment and the ecosystemis getting more and more serious, therefore, it is a top priority to research and developa friendly, environmental and efficient desulfurization method. Traditional flue gasdesulfurization method has the shortcomings of high investment,difficult toregenerating absorbent, difficult to recycling sulfur dioxide, the new organic aminedesulfurization has the advantages of high desulfurization rate, high renewable ability,good recycling effect and no secondary pollution. It is justifiable on the requirementof green organic chemistry, has a very broad application prospects in economicefficiency and environmental protection.In this paper, we designed and synthesized a novel organic amine desulfurization1,4-bis-（2,3-dihydroxypropyl）piperazine, which is used in simulated flue gasdesulfurization experiments under laboratory conditions. We researched differentexperimental conditions to discuss the absorption-desroption performance of1,4-bis-(2,3-dihydroxypropyl) piperazine to sulfur dioxide and evaluated theapplication performance of the organic amine we synthesized in laboratory bycomparison with several other types of desulfurizers.Firstly, in the synthesis experiments, epichlorohydrin hydrolyzed withring-openning under acid condition into3-chloro-1,2-propylene glycol, then reactedwith anhydrous piperazine to1,4-bis-(2,3-dihydroxypropyl) piperazine. The optimalhydrolysis conditions of epichlorohydrin are as following: the mass fraction of dilutedsulfuric acid is10%, the reaction temperature is100℃, the reaction time is2hours,the yield is79.2%. The synthesis conditions of1,4-bis-(2,3-dihydroxypropyl)piperazine are as following: anhydrous methanol as a reaction solvent, n(anhydrouspiperazine):n(3-chloro-1,2-propanediol) is1:2.2, the reaction is carried out underreflux condition, the reaction time is7hours, the yield is87.6%. Secondly, in the absorption-desroption experiments to sulfur dioxide of1,4-bis-(2,3-dihydroxypropyl) piperazine, the sulfur dioxide and nitrogen were mixedto obtain the simulated flue gas, we discussed the influences of absorption-desroptionconditions such as: the temperature, the concentration, the flow of flue, etc. Determinethe optimal conditions of absorbing sulfur dioxide are as following:the temperature ofabsorption is60℃, the concentration of absorbent is0.3mol/L, the simulated flue gasflow rate is0.5L/min,the concentration of sulfur dioxide in flue gas is8mg/L,the rateof desulfurization is99.39%.The optimal conditions of desorbing sulfur dioxide are asfollowing:the temperature of desorption is105℃,the time of desorption is2h,the wayof desorption using direct heating.In the process of absorption and desorption,theinitial pH value of absorption solution should be controlled between5.6to7.0and therate of desorption is96.52%.Thirdly, we researched the desulfurization of several common organic aminewith the same experimental conditions of the absorption-desroption experiments tosulfur dioxide of1,4-bis-(2,3-dihydroxypropyl) piperazine.By studying comparativelywe evaluated the different ability to absorb and desorp sulfur dioxide.1,4-bis-(2,3-dihydroxypropyl) piperazine has high absorption capacity, high desulfurizationrate,and the speed of desroption is fast.It can achieve high desorption rate in arelatively short period of time,so it is a good new organic amine desulfurization agent.After comparison, we believe that the novel organic amine desulfurizersynthesized in laboratory has good desulfurization performance. The advantange ofthe product are as following: easy to synthesize, operability, high melting point, goodstability, less bolatile, higher desorption temperature, low toxicity, low corrosion toequipment, and1,4-bis-(2,3-dihydroxypropyl) piperazine is a diamine compoundhaving two amion which has the abilities of high sulfur dioxide absorption and easy todesroption because of the poor stability of the aminoalkylene sulfate reaction. So ithas high application prospects and economic benefits in flue gas desulfurization field.