对苯二甲酸装置设备的腐蚀与选材原则

CORROSION OF PTA UNIT AND PRINCIPLES OF MATERIAL SELECTION

氧化法制精对苯二甲酸装置是一个强腐蚀系统,设备的腐蚀形态主要有在乙酸及溴化氢溶液中的均匀腐蚀,由Br^-及Cl^-引起的点蚀、间隙腐蚀、应力腐蚀以及氢脆。考虑到医药级PTA产品纯度的要求,装置中凡接触工艺物流的设备其主体材料起码应采用304SS/304LSS钢;其它设备应根据腐蚀的具体情况采用含钼的不锈钢,如316SS/316LSS,317LSS,904LSS,254SMO,Duplex2205,Hastelloy C和276等钢,甚至采用更高级的钛材如Ti2,Ti7, Ti11以及氟塑料衬里等。

The PTA unit displays very serious corrosion. The status of corrosion involves general corrosion in HAc and HBr solution, and pitting , crevice corrosion and stress corrosion cracking resulting in Br^-and Cl^- , as well as hydrogen embrittlement. In order to meet the requirement of pharmaceutical PTA product, 304SS/304LSS and the better have been used for shells of all the equipments contacting the process fluids. Based upon the corrosions status, other different grades of stainless steels containing Mo, such as 316SS/ 316LSS,317LSS,904LSS,254SMO, Duplex2205, Hastelloy C and 276, etc. have been used for the equipments. Also Ti2,Ti7, Ti11 and fluorin plastics lining are selected when necessary.