The Analysis To The Reason Of Invalidation And Study On Preventing Measure For No.1 Effective Evaporator Of Cca Plant

There have been serious corrosive problems in the caustic liquor evaporator of the 200000T/Y CCA plant in QILU Petrol-chemical Company Chlor-Alkali factory since it is started operation in 1988. The pipes of its heater have been regularly damaged that causes its invalidation for about every 2~3 years. That results in a huge passivity to the plant production and causes a great loss in economy. Closely connecting with the actual production, combining with a lot of experiments and analysis, and assisting with the methods of calculation and electron microscope analysis, the article deeply systemically analyzes and studies the work condition of the heater and various reasons that may cause the invalidation. The selection of material for the equipment is also studied under this work condition. Some useful conclusions are gived as follows:1,There are many kinds of factors that result in damage by invalidation under the work condition of the heater. The interaction of the various factors aggravates the damage by invalidation of it.2,The higher the temperature of the heater is, the faster the corrosive rate is.3,To a certain temperature, caustic liquor with higher concentration can relatively increase the stability of the chlorate, and reduce the equipment cauterization caused by decomposition of chlorate.4,Super ferroferrite stainless steel EB26-1 is the best material to be used under this work condition.5,To add expanding section in the heater's shell can improve the state of the pipes under the work condition, and can also increase the lifetime of the heater. As well, against the reasons of damage caused by invalidation the preventing measures are presented, which have great signification in operating, fabricating and maintaining the heater in the future, and also have a higher value of reference for the similar problems in the domestic Chlor-Alkali Industry.