毕业设计外文翻译8000吨/年醋酐装置精馏工段工艺设计Acetic anhydride production processAcetic anhydride is a colorless volatile, with a strong irritating smell and corrosiveness liquid. Name of acetic anhydride, molecular formula C4H6O3, the flash point of 64.4 DEG c.. Density of 1.082 0g / cm3. Melting point - 74.13 DEG c.. The boiling point of 138.63 DEG c.. The refractive index nD 1.390. 20 degrees of viscosity of 0.91 mPa? S. Spontaneous ignition temperature of 388.9 DEG c.. Soluble in cold water, in water is decomposed into acetic acid, ethyl acetate and ethanol production. Soluble in chloroform, ether and benzene. Toxic, eye and mucosa has a strong irritating, mass concentration of 0.36 mg / m3 when the eye irritation; 0.18mg / m3, can change a person's brain electrical image, can cause tissue protein modification. The steam stimulation is stronger, extremely easy to burn the skin and eyes, such as frequent exposure can cause dermatitis and chronic conjunctivitis. On rat oral LD50 was 1780 mg / kg. When spilled and or adhesion to the skin, to immediately with water or 2% washing soda, systemic poisoning should be timely medical treatment. Air max allowable volume fraction 5 u L / L.Acetic anhydride is the country to encourage the development of basic organic chemical raw materials, mainly used for the production of cellulose acetate, of which two cellulose acetate is used in the manufacture of cigarette filter tip and plastic, three cellulose acetate is the manufacturing of advanced film material, is widely used in medicine, pesticides, dyes, military, spices, metal finishing industries.Acetic anhydride is" precursor" products, acetic anhydride production, management must be in the public security organ for archival filing certification, enterprises sold every batch of goods to perform detailed registration, and to the public security organ for the record. According to the legal provisions, to undocumented units 200 kg acetic anhydride, will be sentenced to 3 years imprisonment.Industrialization of acetic anhydride production process has three kinds: the oxidation of acetaldehyde, ethylene ketone and methyl acetate carbonylation.Acetaldehyde oxidation technology source for the Canadian Sha Winigan chemical company. The production process is as follows: acetaldehyde and oxygen at 60 degrees C, 101 kPa or 70 degrees C, 600-700kPa under the conditions of the oxidation reaction, oxygen or air as the oxidant, using ethyl acetate as solvent, cobalt acetate as catalyst, acetic acid copper as promoter. Acetaldehyde and oxygen ( in excess of about 1%-2%) reaction is first generated peroxy acetic acid, acetic acid and acetaldehyde reaction of acetic anhydride and acetic acid. Under this condition, the conversion rate of acetaldehyde acetic anhydride and acetic acid production rate is 95%, the mass ratio of 56: 44. The total yield of 70%-75% acetic anhydride. By changing the processing conditions, can improve the yield of acetic anhydride. Reaction equation:CH3CHO+O2 - CH3COOOH;CH3COOOH+CH3CHO CH3COOOCH ( OH )CH3 ( single peroxy acetic ester );CH3COOOCH ( OH ) CH3 - ( CH3CO ) 2O+H2O;CH3COOOCH ( OH CH3 2CH3COOH ).Acetaldehyde acetic anhydride consumption per ton of 1.165 T, 2300 m3 standard air. Acetaldehyde oxidation method has the advantages of simple process, technology is mature, but the serious corrosion, high consumption, has gradually been eliminated. In foreign countries have been carbonylation of methyl acetate and vinyl ketone method alternative. China Shanghai Chemical Reagent Factory of this device has been in a state of production.Vinyl ketone law in accordance with the different materials can be divided into: acetic acid and acetone method.Acetic acid process technology from Germany Wacher chemical company. The production process is as follows: in the first step, the acetic acid in 700-750 C,10-20kPa pressure and 0.2%-0.3% phosphoric acid three ethyl ester (by acetic acid quality plan) as catalyst under the conditions of dehydration, cracking ethylene ketone acetate made, conversion rate is about 85%-90%, on vinyl ketone selectivity (corporeal quantity meter ) is about 90%-95%. Reaction equation:CH3COOH CH2 = C = O+H2O+147 kJ / mol.The second step is to absorb liquid acetic acid ethylene ketone anhydride generating, by distillation and purification to obtain the product of acetic anhydride, vinyl ketone conversion rate of about 100%. Reaction equation:CH3COOH+CH2 = C = O ( CH3CO ) 2O+62.8kJ / mol.The production process is a German Wacher chemical company to develop a success, and in 1936 achieved industrialization. Two existing production process:One, as the tower process. Using 4 packed tower for synthesis and separation. The consumption of per ton of acetic anhydride as catalyst, acetic acid 1.35t, 1.5-2kg 0.7-1.0kg 100-160kg, ammonia, acetic acid recovery.Secondly, as the liquid ring pump flow. The liquid ring pump for reaction and absorption equipment. The process is simple, being replaced by tower process. Per ton of products consumption quota for acetic acid cracking rate, 1.22 T, 75%, the yield of synthesis of 96%.The production process is as follows:The first step is to acetone in 700-800 C, atmospheric pressure, no catalyst under the conditions of the cleavage reaction. Reaction equation:CH3COCH3 CH2 = C = O+CH4-79.53 kJ / mol.The second step is to absorb the liquid acetic acid ethylene ketone anhydride generating. Reaction equation:CH2 = C = O+CH3COOH ( CH3CO ) 2O+62.8kJ / mol.But in the same scale, acetone and acetic acid, acetone method requires larger cracking furnace, absorption tower and the washing tower, and an increase in cyclic acetone water distillation separation and other auxiliary equipment, the project construction cost is high. At the same time, the production cost is also higher acetone method.Ketene process relative acetaldehyde oxidation and carbonylation of methyl acetate to the process, the process is complex, a lot of side reactions, high energy consumption, low profit. Due to the production technology is mature, abroad in the early construction device using this method, in our country is still widely used.In 1973, Halcon Scientific Development Corporation obtained the carbonylation of methyl acetate to acetic anhydride production of patent. In 1983, the company cooperates with American Eastman-Kodak company built up the first set of the carbonylation synthesis of acetic anhydride production device. Celanese company also has this technology. The production process is as follows: the first is the methanol and acetic acid in sulfuric acid under the action of catalyst to generate methyl acetate, the reaction pressure is normal pressure, reaction temperature of 65-85 C, the acetic acid conversion rate of about 100%. Then, methyl acetate and methanol and carbon monoxide in the methyl iodide and rhodium catalyst or nickel catalysts ( for rhodium catalyst catalytic activity of Ni catalyst is 10 times, so the industrial use of rhodium catalyst ) presence, for carbonylation reaction of acetic anhydride and acetic acid, cogeneration. The reaction pressure is about 2.55 MPa, reaction temperature 180 degrees celsius. The acetic acid / acetic acid ratio can be adjusted according to the requirement. Reaction equation:CH3COOH+CH3OH - CH3COOCH3+H2O;CH3COOCH3+CO ( CH3CO ) 2O;CH3OH+CO - CH3COOH.Methyl acetate carbonylation with a short process, products of good quality, low consumption, less waste discharges etc., represents the advanced level of production technology of acetic anhydride. At present, the main foreign suppliers areused in the process of acetic anhydride. Liquid phase process than gas phase process maturity. British BP company in Halcon and Monsanto synthesis of acetic anhydride carbonylation to acetic acid based on technology, the successful development of the carbonylation of methanol and acetic anhydride - acetic acid process, and on 1987 implementation industrialization ( Figure 1 ( omitted) ).Gas phase carbonylation of Hoechst company in 1986 developed, reaction temperature, 185-216 C, by heterogeneous supported catalysts. The catalyst is a precious metals rhodium, iridium, palladium or rubidium contained in silica, three two aluminum oxide, magnesium oxide, two oxide carrier, which showed the highest activity of rhodium. Gas phase esterification reaction with liquid phase method are the same, and liquid phase carbonylation carbonylation are similar. The difference is: the liquid phase carbonylation of methyl acetate in liquid phase carbonylation reaction; and the gas phase carbonylation reactions in the gas phase, gas phase process were removed from the reaction liquid catalyst recovery. Gas phase process can reduce the loss of rhodium, rhodium is fixed on the carrier without the accident was washed out in the solution. Gas phase process in terms of investment is better than that of liquid phase process, but the project cost is higher.In 2003, Dan group of Jiangsu, Chinese Academy of Sciences and Beijing University three homes, built up the first set of acetic anhydride carbonylation synthesis device, device dimensions is 20000 t / a acetic anhydride . The device can also adjust the production of methyl acetate by Lanzhou Petrochemical Design Institute, engineering general contracting and design, production of acetic anhydride purity of the product reached more than 99.5%, more than 99.9% of methyl acetate. A ton of acetic anhydride consumption quota for methanol acetic acid 0.353 T, 0.604t, CO for 0.340t, Z catalyst 0.44, steam 4.2 T, 147 t water, electric 167kwh, instrument air 300m3. Device operation practice proves, developed by China in this set of acetic anhydride production process is reliable. Acetic anhydride carbonylation synthesis process, reactor by esterification and the carbonylation reactor, methanol and acetic acid in the esterification reactor to generate methyl acetate, methyl acetate in carbonylation reactor and CO synthesis of acetic anhydride. Because the process of catalyst in water, generation acetic anhydride - at the same time, also generates a part of acetic acid. The processes for the production of acetic anhydride mainly, main raw material for CO and methanol, acetic acid. In addition, the process also can directly use the raw materials of methanol and CO in the carbonylation reactor in response to acetic acid, without esterification device. Therefore, the process can be based on market demand for acetic acid, methyl acetate and acetic anhydride products switch. by carbonylation catalyst technology is the most important, Institute of Chemistry Chinese Academy of Sciences after years of research and development and development of the domestic catalyst -- multidentate Ji Ji heterozygous rhodium complexes catalyst. And the United States Monsanto developed catalyst, the catalyst has a water content of less. From Jiangsu, the Dan group use, reaction conditions and catalyst abroad basically the same ( reaction pressure 3-6MPa, temperature 160-200 C ), an ideal application.In addition to using rhodium catalyst, the carbonylation synthesis of acetic anhydride process can also be used for other metal catalysts. Although the rhodium catalyst catalytic activity and selectivity for the best, but there are expensive, shortage of resources, recycling costs higher shortcoming. Therefore, many companies have shifted their attention to non noble metal catalysts, which are mainly I A III A B or B, VI, VIII non-noble metals. Among them, nickel catalyst in the reaction conditions such as mild and catalytic properties are obviously superior to other non-noble metal, is a kind of the most development prospect of non noble metal catalysts.Vinyl ketone and carbonyl synthesis process is the production of acetic anhydride used method. From the contrast can be seen in Table 1, ketene process is relatively complex, the product quality is low, the energy consumption is relatively high, high cost, pollution, heavy, small scale.醋酐生产工艺醋酐为无色易挥发，具有强烈刺激性气味和腐蚀性液体。