乙酸乙烯合成用触媒载体活性炭再生新技术

【作者】 马祥元；

【导师】 彭金辉；

【作者基本信息】 昆明理工大学 ， 有色金属冶金， 2006， 硕士

【摘要】 乙酸乙烯单体是生产涂料和粘结剂的重要中间化工原料,目前国内主要采用乙炔法来生产,在乙炔法生产乙酸乙烯的过程中采用载有乙酸锌的活性炭作触媒。然而,触媒使用一段使用时间后会失去活性,造成活性炭的大量废弃,如果不加以回收利用,不仅不利于资源利用,而且会造成环境污染。本论文提出废触媒再生利用新工艺,以促进资源综合利用和生态环境保护,发展清洁生产和实现循环经济,最终实现社会、经济和环境的可持续发展。 本论文以提锌后的乙酸乙烯合成用废触媒为原料,住详细评述了活性炭再生工艺研究进展的基础上,研究了传统加热水蒸气活化再生、传统加热二氧化碳活化再生、微波加热水蒸气活化再生和微波加热二氧化碳活化再生四种活性炭再生工艺,通过实验研究得到了各再生工艺的最佳工艺条件。测定了各最佳工艺条件下再生活性炭的吸附等温线,采用D-A方程、H-K方程、BJH法和DFT理论对活性炭的孔结构进行了分析。并采用扫描电子显微镜对提锌前后及冉牛后的活性炭微观结构进行了分析。另外,结合实验结果,对不同再生工艺进行了对比。 传统加热水蒸气活化再生和微波加热水蒸气活化再生工艺采用正交实验方法,研究了实验中主要因素对再生活性炭吸附性能和得率的影响。得到传统加热水蒸气活化再生活性炭的最佳工艺条件为:活化温度1000℃、活化时间90min、水蒸气流量3.95g/min,在此条件下得到的活性炭碘吸附值、亚甲基蓝吸附值、乙酸吸附值、比表面积和得率分别为1181.1mg/g、16mL/0.1g、590.77mg/g、1308.13m~2/g、62.86%。微波加热水蒸气活化再生活性炭的最佳工艺条件为微波功率700W,活化时间40min,水蒸气流量2.03g/min,在此条件下得到的活性炭碘吸附值、亚甲基蓝吸附值、乙酸吸附值、比表面积和得率分别为1193.85mg/g、19mL/0.1g、571.32mg/g、1547.74m~2/g、65.36%。 传统加热二氧化碳活化再生和微波加热二氧化碳活化再生工艺采用条件实验方法,通过研究再生工艺中主要因素对活性炭吸附性能和得率的影响,得到传统加热二氧化碳活化再生活性炭的最佳工艺条件为:活化温度1000℃、活化时间100min、二氧化碳流量0.5m~3/h,在此条件下得到的活性炭碘吸附值、亚甲基蓝吸附值、乙酸吸附值、比表面积和得率分别为1091.33mg/g、14mL/0.1 g、518.30mg/g、1178.28m~2/g、80.33%。微波加热二氧化碳活化再生的最佳工艺条件为微波功率700W,活化时间25min,二氧化碳流量0.2 m~3/h。在此条件下得到的活性炭碘吸更多还原

【Abstract】 Vinyl acetate monomer is an important chemical intermediate utilised in the production of a variety of different paints, adhesives and surface coatings. Vinyl acetate is mainly produced industrially via the gas phase acetoxylation of acetylene over activated carbon-based catalysts. Its activation vanished after a period of time result in the samples being abandoned. The exhausted catalyst would bring out resource waste and environment pollution. This dissertation presents a new method for disposal of exhausted catalyst, which aims to promote comprehensive utilization of resources and urban environment, implement circuit economy and cleaner production,and achieve stainable development of society, economy and environment.The purpose of this dissertation aims to regenerate exhausted activated carbon-based catalyst using in vinyl acetate production process, in which zinc element was extracted. On the base of reviewing the development of progress in activated carbon regeneration in detail, four regeneration techniques by different activation method that include water vapor activation with electric furnace and microvave as heating agent, carbon dioxide activation in the same heating agent have been studied,and the optimum conditions were obtained through experimental investigation. The adsorption isotherms of the activated carbons which obtained from optimum conditions were determined. The pore structures of samples were analyzed by DA equation, HK equation, BJH method and DFT theoretic. In additional, the microstructures of exhausted activated carbon-catalyst, spent activated carbon after extraction of zinc and activated carbon product were characterized with the help of SEM. Furthermore, the regeneration techniques have been compared combining with the experimental results.The factors involving the influence on the properties of activated carbon, such as activation temperature, microwave irradiation power, activation time and the flow rate of water vapor, have been studied via orthogonal experiments while the activation agent is water vopor. The optimum condition for traditional heating has been obtained as follows: activation temperature is 1000℃ while activation time 90min with the flow rate of water vapor being 3.95g/min. Thus, the experimental results have shown thatthe yield of the activated carbon was 62.86 % when the adsoption value of iodine adsorption, methylene blue adsorption, acetic acid adsorption reached 1181.1 mg/g, 16 mL/ 0.1 g, 590.77mg/g with the surface area 1308.13m2/g. When the heating resource changes to microwave, the optimum condition is microwave power 700W, activation time 40min with the flow rate of water vapor being 2.03g/min. The iodine adsorption, methylene blue adsorption, acetic acid adsorption, surface area and yield of the activated carbon regenerated under above condition are 1193.85mg/g, 19 mL/O.lg, 571.32mg/g, 1547.74m2/g, 65.36%, respectively.When the activation agent is carbon dioxide, the regeneration process have been studied via conditional experiments. The optimum condition for traditional heating method has been obtained as follows: activation temperature 1000 °C, activation time 100 min and the flow rate of carbon dioxide is 0.5m3/h. The iodine adsorption, methylene blue adsorption, acetic acid adsorption, surface area and yield of the activated carbon regenerated in optimum condition are 1091.33mg/g, 14mL/0.1g, 518.30mg/g, 1178.28m2/g and 80.33%. Futhermore, the optimum condition for microwave heating method is microwave power 700W, activation time 25min and the flow rate of water vapor 0.2m3/h. The iodine adsorption, methylene blue adsorption, acetic acid adsorption, surface area and yield of the activated carbon regenerated under above condition are 1158.02mg/g, 16mL/0.1g, 564.43mg/g, 1254.51m2/g and 74.19%, respectively.The results show that the four regeneration techniques are feasible for regeneration of activated carbon-based catalyst using in vinyl acetate production.The idion adsorption, methylene blue adsorption of the all samples obtained under optimum conditions achieve the first grade standards in the GB/T13803.1-1999, GB/T13803.2-1999 and GB/T13803.4-1999. The acetic acid adsorption of the samples regenerated by water vapor achieved the A grade in GB/T13803.5-1999. When the activation agent is carbon dioxide, its acetic acid adsorption achieved the B grade in GB/T13803.5-1999.The pore size distribution carves show that the misopores content of the activated carbon prepared by microwave heating is more than that by conventional heating using the same activation agent. In the same heating resource, the mesopores content of the activated carbon obtained by water vapor activating are more than that by carbondioxide.Through SEM pic, many adsorbent can be observed on the surface of the xhausted activated carbon-catalyst, but the adsorbent died away after extraction of zinc, and the pore strcture formed after regeneration disposal.Through the comparison of different regeneration prosesses, it can be found that the regeneration process by microwave heating and activated by water vapor have many advantages such as short regenerating time and high-quality of product and so on.更多还原