Jacketed Vessel

A jacketed vessel has a second shell around its outer wall, forming a cavity through which a heating or cooling fluid is circulated. Steam, hot oil, water or chilled glycol passes through the jacket, transferring heat through the vessel wall to or from the contents without ever contacting the product.

This indirect approach is what makes controlled temperature possible at manufacturing scale. Applying heat directly to a vessel wall creates hot spots that can degrade product or trigger unwanted reactions; a circulating jacket distributes thermal energy evenly and can be reversed quickly from heating to cooling if a reaction begins running faster than intended.

Jacket performance is a real constraint rather than a detail. Heat transfer depends on the surface area available relative to the volume of contents, and that ratio worsens as vessels get larger. A reaction easily controlled in a small vessel may exceed the cooling capacity of a bigger one, which is a central issue in scale-up and a good question to ask any manufacturer quoting on exothermic chemistry.

Jacketed vessels appear throughout chemical manufacturing - in reactors, blending tanks and storage where temperature must be held. See heating and cooling processes and temperature-controlled manufacturing.

Where your product involves reaction chemistry, ask specifically about cooling capacity rather than just vessel size. A large reactor with modest cooling may be a worse fit than a smaller one that can remove heat quickly. It is also worth asking what heating and cooling media the site has available, since steam, hot oil and chilled glycol reach different temperature ranges and not every manufacturer has all of them.

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