Application Research Of MVR Technology In The Production Of Analgin

Analgin is a kind of commonly used prescription drugs which has significant antipyretic effect and strong analgesic action and can be used to treat toothache, muscle pain, headache, acute arthritis and rheumatic pains, etc. It was found that there were still many problems in the process of producing analgin, though it has been be put into production for more than fifty years in our country. A lot of sodium sulfate and ammonium sulfate waste liquor are produced in the process of analgin production. These waste liquor are evaporated by the workshop except partly were transported out. Double-effect evaporator process is used to deal with these waste liquor. And annual steam consumption accounted for about 85%-90% of the total cost, energy consumption is serious. As a result, the main point of energy saving work should be focused on the reduction of the steam consumption. Evaporator is a big consideration for energy saving as the only steam-using equipment in the whole production process.To meet the increasingly stringent requirements of environmental protection and make full use of resources, a new process was proposed in this paper to replace the double-effect evaporator process with MVR (Mechanical Vapor Recompression) to deal with salty wastewater under a lot of literature reading and considering the self-condition of the company. Salty wastewater was put through the MVR equipment, low quality and low temperature vapor of feed liquid would be extracted. The temperature, pressure and enthalpy increased after the vapor were compressed by compressor. Heat exchange happened in heat exchanger between high-quality vapor and feed liquid. The temperature of feed liquid was improved which benefited the continuous and more sufficient evaporation of feed liquid. Secondary steam which was wasted in the past could be fully recycled and used. The heat of secondary steam could be continuous used in evaporator system after the secondary steam was compressed by mechanical thermal compressor. As a result, the system temperature could be improved by 5-20℃. Fresh steam is only used to supple heat loss and enthalpy loss of feed, the fresh steam consumption of MVR evaporator was greatly reduced.The new technology not only has a high degree of automation, but also thoroughly solves the high vapor consumption during the process of evaporation concentration crystal of sodium sulfate mother liquor. The new equipment is easy andsimple to handle, the energy-saving effect is obvious. Taking deal with sodium sulfate waste liquid as an example, according to the actual production, the power cost is 475.79 yuan/t of processing waste liquid with original double-effect evaporation. The power cost is 179.72 yuan/t of processing waste liquid with MVR technology, cost savings is 62.2%. The total investment of new technology is about 6.65 million yuan, of which fixed assets investment is about 5.95 million yuan. The throughput of sodium sulfate is assumed as 6900 t, more than two million yuan can be saved for the company. It will take 3-4 years to recover its investment cost, economic benefit is considerable. Compared with the original double-effect evaporation, the leakproofness of new technology is good and odor problem is basically eliminated with a good environmental benefit.