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设计总说明：甲醛广泛用于有机合成、合成材料、涂料、橡胶、农药等领域，国内外市场需求和价格逐年提高，有着广阔的应用前景。甲醛是一项重要的工业产品，此行业近几年发展迅速，它的需求从发展的初始阶段到如今，呈现递增的趋势。甲醛生产的工艺由最初的浮石银生产法逐渐向多元化发展，随着近几年铁钼氧化物催化氧化法工艺装置的不断建设投产，在生产工艺上已经从单一的电解银法逐步向银法与铁钼法共同发展，同时从原料入手的科研和试生产以低碳烃、甲烷、二甲醚为原料的工艺路线也得到了良好的发展。甲醛的生产方法有多种, 目前工艺比较成熟的有甲醇空气氧化法(其中包括甲醇过量法和空气过量法) 、甲缩醛氧化法。其中利用甲醇空气氧化法生产甲醛主要有两类不同的工艺，其一是采用银催化剂的“甲醇过量法”，也称“银催化法”（简称“银法”）；其二是采用铁钼氧化物催化剂的“空气过量法”，也称“铁钼催化法”（简称“铁钼法”）。银法甲醛主要使用银催化剂，反应中甲醇占比较高，最终产品中剩余甲醇较高，必须经过精馏装置脱除。银法生产工艺过程中，混合气中甲醇的浓度较高，设备的负荷量较大、投资较少，除此之外还具有能耗低，产品甲酸含量低催化剂可再生循环使用等优点；但是甲醇转化率较低、催化剂易中毒，且产品浓度仅限为37%左右的甲醛溶液。铁钼法甲醛生产工艺同样是以甲醇和空气作为反应原料，甲醇在过量空气的环境中氧化制得甲醛，以铁钼混合氧化物为主要成分的催化剂，选择性较高，产品纯度高于银法。铁钼氧化物催化剂的耐毒性较好，但是也存在一定的缺点，如流程复杂、投资大、耗能高及产品甲酸含量高等。本课题以实际的甲醛生产装置与工艺参数为依据，通过查阅有关资料和结合实际铁钼催化法制甲醛的生产过程，针对年产6万吨的铁钼催化法合成甲醛的设计任务。主要的设计参数有：原料甲醇质量分数为7%，水的质量分数为93%；原料甲醇温度是20℃；进料空气温度：50℃；氧醇比δ为0.38；配料浓度质量分数为60%；甲醇单耗e为0.427t/1t（均按每小时计）。确定合成的工艺路线和生产流程、确定工艺参数、确定设计方案，进行相关的物料衡算和热量衡算，完成蒸发器、反应器、吸收塔等主要设备的设计和生产所需设备进行选型，用AUTOCAD绘制带控制点的工艺流程图、车间设备布置图及主要设备设计图等，并编制和撰写设计说明书。
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关键字：甲醛；铁钼催化法5425
The process design of methanol iron-molybdenum catalytic method for formaldehyde
Abstract：Formaldehyde is widely used in organic synthesis, synthetic materials, paint, rubber, pesticide and other fields, the domestic and international market demand and price increase year by year, and has broad application prospects. Formaldehyde is an important industrial products, the industry developed rapidly in recent years, it needs from the initial stage of development to the present, present increasing trend. Process of formaldehyde production by pumice silver production method of initial gradually persified development, along with the continuous construction of production in recent years the iron and molybdenum oxide catalytic oxidation process equipment, in the production process of electrolytic silver method from single to silver and molybdenum iron law of common development, technology research and trial production from the raw material starting with low carbon hydrocarbon, methane, two ether as raw material has also been a good development. There are many kinds of production methods of formaldehyde, the current relatively mature process with air oxidation of methanol method (including the excess air and methanol excess method), methylal oxidation method. The production of formaldehyde by methanol oxidation method mainly has two kinds of different processes, one of them is the use of silver catalyst "methanol excess method", also known as "silver catalysis" (referred to as the "silver"); the second is the use of iron molybdenum oxide catalyst "excess air law", also known as the "iron molybdenum catalytic method." (referred to as the "iron molybdenum method"). Silver formaldehyde mainly use silver catalyst, reaction of methanol in a higher proportion of residual methanol, high end product, must pass through the distillation device removal. The production process of silver process, methanol mixed gas of high concentration, load, less investment in equipment, in addition also has the advantages of low energy consumption, low acid content of the products of catalyst recycling; but the methanol conversion rate is low, the catalyst poisoning, and formaldehyde solution concentration is only about 37% . Production process of molybdenum iron law of formaldehyde is the same with methanol and air as reaction raw materials, methanol in air environment is oxidized into formaldehyde, catalyst, with iron molybdenum mixed oxide as the main component of the high selectivity, the purity of the product is higher than that of silver method. Iron molybdenum oxide catalyst toxic tolerance is better, but also has some disadvantages, such as complex process, large investment, high energy consumption and high acid content of the products. This topic in formaldehyde production device and the actual process parameters as the basis, through access to relevant information and combined with the actual iron-molybdenum catalytic method for formaldehyde production process, design for the task of iron-molybdenum catalytic synthesis of formaldehyde with an annual output of 60000 tons. The main design parameters are: the methanol mass fraction is 7%, the water mass fraction is 93%; the raw material methanol temperature is 20 ℃; inlet air temperature: 50 ℃; the ratio of oxygen to methanol δ 0.38; mass fraction concentration ingredients for 60%; methanol consumption e 0.427t/1t (as per hour). To determine the route of synthesis and production process, determine the process parameters, determination of design scheme, material balance and heat balance calculation related, complete the design and production of evaporator, reactor, absorption tower and other major equipment required for equipment selection, drawing with the control points of the process flow chart, workshop equipment layout and the main equipment design with AUTOCAD, and compile the design specification.