Article originally published in 2.2.2021
Previously, product heating and rapid cooling in the chemical production process were performed in a jacketed reactor. This design caused problems that resulted in production downtime and high maintenance costs. Finess solved these challenges by supplying four XTube heat exchangers to the site. They are ideally suited for a process involving extreme temperature fluctuations and significant changes in viscosity.
At a chemical industry company, the stages of the product manufacturing process include heating and rapid cooling of the product. The process involves very large and rapid temperature fluctuations, which place a strain on the structures of the process equipment.
Changes in the viscosity of the product being manufactured also pose challenges for the structures.
The process steps were previously carried out using large reactors with jacket heating. In practice, these were tanks with pipes circulating heating and cooling water on the outside. This solution was not ideal for a process involving continuous and significant temperature fluctuations. Damage caused by thermal stress had to be repaired frequently, resulting in production downtime and maintenance costs.
Finess solved the structural challenges by designing a system in which cooling and heating take place in a separate heat exchanger outside the reactor. The new design is built to withstand rapid temperature fluctuations, and each heat exchanger module is equipped with expansion joints. A drain was also added to the system, allowing the piping to be easily drained. Finess’s XTUBE double-tube heat exchangers are ideally suited for this type of application, where large fluctuations in temperature and viscosity place a heavy load on the equipment.
Thanks to the successful design, the speed of the production process also increased, meaning the system has more capacity.
“As an added bonus, the customer gained a third benefit: the volume of the production batch increased by the volume of the heat exchanger, meaning the customer can now produce larger batches with the new equipment,” explains Juha-Pekka Paavola, CEO of Finess Energy Oy.
The double-pipe heat exchanger is a specialized product whose design and operating principle are unfamiliar to many. The double-pipe heat exchanger is suitable for demanding media because it features a large, unobstructed flow channel that does not clog. This solution is ideal for processes involving viscous liquids and liquids containing a high concentration of particles, fibers, and the like. The double-pipe heat exchanger is therefore exceptionally well-suited for applications such as wastewater containing particles.
“We delivered four large double-pipe heat exchangers to this chemical plant. The scale of the project is well illustrated by the fact that the delivery consisted of two full truckloads of equipment,” Paavola explains.
The temperature variation in the process is significant: in the same heat exchanger, water at 90 °C circulates in the heating circuit, while water at 7 °C circulates in the cooling circuit. A thermal shock occurs in the process; the transition from one temperature to the other takes place in a matter of seconds.
It was also essential to take thermal expansion into account during the design phase. Structural integrity was ensured by installing expansion joints in each heat exchanger module to compensate for the thermal expansion of the piping.
The handling of chemical substances also places demand on the material itself. XTUBE double-pipe heat exchangers are made entirely of acid-resistant steel.
In addition to the heat exchangers, the scope of delivery included thermal insulation for the heat exchanger tubes and an enclosure surrounding the entire unit. These accessories reduce heat loss from the equipment and serve as protection against condensation.