Hot oil application up to 450°C
Several industrial processes, the chemical and petrochemical industry, uses heat transfer liquids to absorb heat energy from one place to another. It is particulary utilize in the solar thermal power stations worldwide. The characteristic fluid for this applications is water and steam up to an operating temperature of 200 °C due to high specific heat value.
In addition, the usual heat transfer oil is used for servics with a temperature range between 200 and 450 °C.
HERMETIC-Pumpen GmbH provides a suitable technology with sealless canned motor pumps for high temperature application, especially for thermal power stations.
Task
High-temperature applications with a fluid temperature up to and higher than 320 °C are a challenge for every convential chemical pump. This type of pump design have to install a thermal barrier between the pump and external motor. Within the conventional centrifugal pump, the end user needs to install a compensator to isolate the pump nozzles from mechanical forces and torques transmitted through the piping.
The mentioned design of a conventional pump often leads to a risk of failure due to several impacts of different working units to avoid any leakage of the liquid. The canned motor pump can be used as a better solution because of the monobloc design, pump and motor working as one unit.
Solution
The technology of sealless pumps has the advantage of a real double safety containment, no mechanical seals and roller bearings, no lubrication of sealing, no shaft aligment and a low noise level to protect the employees and especially the environment.
Canned motor pumps as one unit are designed and available in two options for high-temperature applications:
1.) Canned motor pumps with external cooling and heat exchanger (Fig. 1)
2.) Canned motor pumps without external cooling (Fig. 2)
If cooling water is available at the plant, the design with external cooling (Opt. 1) is a preferred solution. The canned motor pumps will be equipped with a heat exchanger which can mounted around the motor. For this design the casing housing is separated from the motor by a narrow, circumferential gap that acts as a thermal barrier. Within this thermal barrier this design avoids the thermal heat transfer to the motor part.
The second option uses a silicone-ceramic insulation winding that withstands temperatures up to 450 °C and liquid temperatures up 400 °C without any external cooling required. Fins on the motor casing improve the heat dissipation through natural convention.
The sealless technology of HERMETIC canned motor pumps is one of the most suitable choice for the high-temperature applications and already used by various companies in the power generation industry.
