Chemical and pharma industry both require a fine and accurate temperature regulation of ingredients and products during the whole production process, as we have already discussed the topic several times yet. In Tempco we’ve recently developed an interesting application for a chemical company, with the supply of thermoregulation units in the production of additives for a series of different chemical products intended for various markets, lubricants, plastic, water and oil. The thermoregulating units are employed on production reactors.
The customer has heat transfer oil available at high temperatures, +270° C, coming from a boiler in the facility, allowing for the development of a heat recovery solution with an oil/oil heat exchanger on the heating circuit, enabling a temperature regulation of products in a range of temperatures between +10° and +200° C. Heating fluid is Therminol 66, while the working fluid is Therminol D12.
The cooling circuit is equipped with a water/oil heat exchanger, receiving water at 30° C from an evaporative tower, pumped into a heat exchanger suited for water at 10°C allowing future further extensions of the thermoregulation range.
The most challenging part of the project was the oil/oil heat exchanger, involving diathermic oil at very high temperatures and thus requiring an accurate evaluation of materials expansion rates, on heat exchangers, pipings and internal connections. We’ve selected special shell and tube heat exchangers with U-tubes design, which allow the tubes to move inside the shell without the need of expansion compensation on the shell itself. All the internal connections are flange joints and/or welded, with expansion compensation joints near the most critical sections for thermal expansion.
The units are in Atex zone 2 IIG execution for explosive environment, and are so equipped with:
– Atex thermostat for maximum temperature level control
– Atex pressure switch for maximum pressure level control
– Atex temperature sensor with 4-20 mA transmitter
– three port ON/OFF valve for heat/cold exchanger selection DN125, complete with a pneumatic actuator and shuttle valve
– Two port ON/OFF valve on water cooling circuit, complete with pneumatic actuator and shuttle valve
– Two port modulating valve on Therminol 66, complete with modulating electro-pneumatic actuator
– Two port ON /OFF valve for Therminol 66 isolation complete with pneumatic actuator and shuttle valve
Usually, this kind of applications have narrow installation spaces, so that we had to make the thermoregulating unit as compact as possible. At this purpose we installed the exchangers sloped, and it implicated special customized pipings with tailored components and additional evaluations such as material expansion projected on the angle ratio, the correct evaluation of angles in order to ensure the proper functional drainage and internal sections of the exchangers suitable for a sloped installation, and also special support structures which allow the heat exchangers to move for expansion compensation.
Finally, the flange connections are not only intended to avoid oil leaks, a very critical event in case of Atex environments, but they also provide an easy installation. Flange connections guarantee indeed to obtain correct installment values, while in case of threaded connections one or two thread rotations are enough to get off quota, increasing in addition the risk of oil leaks.
