Heat exchangers are one of the most important and widely used pieces of process equipment for the chemical process industries. Throughout the chemical industries there is always the need to control the temperature of corrosive liquids or to condense corrosive gases as part of the chemical process. A heat exchanger is a device used to efficiently transfer energy from one fluid into another fluid. Hence there are many types of heat exchangers employing tubes or plates through which the two process streams will flow. They then exchange the heat between the streams.
When handling corrosive media such as hot sulfuric, hydrochloric, and hydrofluoric acids, proper material selection and design of the heat exchanger is critical. The elevated temperatures of the acids make them extremely corrosive to most metals. Due to potential for corrosion, exotic alloy metal-tubed heat exchangers have been developed in an attempt to provide corrosion resistance for an acceptable service life of the equipment. Therefore, these exotic metals are difficult to weld and work with and are extremely expensive with each having their own limitation. Additionally, minor amounts of contaminating elements such as chlorides or sulphates can render even an exotic alloy heat exchanger not usable.