Why do we need Shell and Tube heat exchangers?
Shell and tube heat exchangers are widely used in the chemical processing industry for heating, cooling, condensing, and evaporating highly corrosive liquids and gasses. Sulfuric acid is the chemical most commonly used with Niche FPP heat exchangers. The process of making sulfuric acid can vary, but any company dealing with the manufacturing process has a high potential for the use of a fluoropolymer heat exchanger in their process. Other acids commonly requiring fluoropolymer heat exchangers are hydrochloric, nitric, and hydrofluoric acids. In another chemical manufacturing industry, fluoropolymer heat exchangers are used in the Chlor-alkali manufacturing process.
The Chlor-Alkali process produces chlorine as well as sodium hydroxide, ammonia hydroxide, and hydrogen peroxide through an electrolytic cell. Once the process is complete, the chlorine must be cooled and dried, and the caustic must be condensed. Other applications ideal for fluoropolymer shell and tube heat exchangers are the manufacturing of bromine, an electronic chemical market that produces ultra-high purity acids for the semiconductor industry, and the lead acid battery industry, which uses sulfuric acid in the manufacture of battery paste.
Shell and tube heat exchangers are more dependable than any of the other vast array of heat exchangers that these chemical processing plants must choose from. Unlike the very popular gasket plate and frame heat exchangers, there are very few gaskets to worry about, as opposed to the plate and frame heat exchangers that have dozens, if not hundreds, of expensive gaskets. Quite often, the gaskets for these heat exchangers are more expensive than the heat transfer plates themselves. With a limited life cycle of the plate gaskets, the cost of replacing these gaskets quite often approaches the original cost of the entire heat exchanger. Plus, it is not uncommon to need to replace these gaskets every 2 to 3 years. That original low price that was paid for these types of heat exchangers is now negated by this sudden cost.
The Shell and tube heat exchanger, with only 4 or so total gaskets, offers a much longer lifespan than the other types of heat exchangers available. Shell and Tube heat exchangers are typically much more rugged and can handle much harsher operating conditions such as higher temperatures, higher pressures, and more aggressive fouling fluids with the ever-present solids embedded in the process stream. The other heat exchanger types will quickly foul and/or plug with the presence of these in the process stream resulting in vastly reduced heat transfer performance yielding lower process output. Overeager, heavy-handed plant mechanics very often can and will do mechanical damage to the more fragile other types of heat exchangers. The more rugged Shell and Tube heat exchanger will prevent them from inflicting that kind of life-ending mechanical damage to the heat exchanger. Despite their good intentions, plant mechanics will inflict mechanical damage to these more fragile heat exchangers as they simply do not understand the mechanical limits of these fragile heat exchangers.