Internal heating and cooling
One example of our laser welded plates immersed in a product is that our plates are used in oil storage tanks and sulfur tanks for temperature maintenance inside the storage tank. The plate assemblies are installed evenly over the ground surface of the tank to distribute the heat evenly. The plate configuration assure fast heating due to “chimney” effect and fast temperature control inside the tank.
One of the other pillowplate assemblies is the suction heater or bayonet heater. These are plate heat exchangers which can be placed in flange opening for direct heating of for keeping the viscosity low for easily pumping the liquid inside the vessel. These are convenient for retrofit applications or heat exchangers that are easily taken out for cleaning or replacement. The heater is inserted and mounted through the manway on the tank.
External heating and cooling
If putting a heat exchanger directly into the product is not an option, or if additional heating and/or cooling is required, our clamp-on plates can be used. Clamp-on plates allow heat exchanger surface to be placed on the outside of the tank. A heat transfer mastic between the plate and the tank is often used to increase the heat transfer between the clamp-on and the vessel wall. Many clamp-on plates are used in this application for the heating of oil storage tanks, sulfur tanks, heavy vacuum gas oil, butyl acrylate, polyethylene, etc. The medium is most commonly thermal oil or, in many cases, steam.
Clamp-on plates also stand out in the area of maintaining temperature in storage tanks, especially if the tanks are located outside, subject to the installation climate. A specific application for our clamp-on plates is the temperature control of sulfur tanks. Maintaining temperature on sulfur tanks is important for safe operation: if not maintained properly, the vapour space above the liquid will get a buildup of gas that reacts with water, causing solid sulfur to form. Solidified sulfur is very corrosive and acts as an insulator. If oxygen becomes present during this process, the storage tank can catch fire. Omega recently supplied clamp-on plates for a project where our plates were placed on the tank shell and top head. The medium used was steam to keep the inside of the tank wall and top head warm, so that the temperature was above the dew point of water and the freezing point of sulfur. Mastic was applied between the clamp-on and tank wall to improve heat transfer.
External jacketing offers the flexibility of supplying heat to the specific parts of the vessel that require it, such as, in the case for sulfur tanks, the vapour space. Using clamp-on plates to achieve heating and/or cooling can eliminate the need for an internal heat exchanger, along with any chance of cross contamination or steam leaks. External steam jackets are typically sized to cover a calculated percentage of the surface area to make up for heat lost to the ambient air. After determining the amount of surface area required, the heated area is distributed uniformly around the tank surface. This ensures uniform heating of a static tank if there is no agitation.
We produced an animation which gives you a good impression of the Clamp-on technique and its use. Our Clamp-on plates are custom made. Please consult an Omega Thermo Products Sales Engineer for more technical specifications.