Watson McDaniel Steam Design Guide

Steam & Condensate Introduction Typical Process Equipment Which Use Steam for Heating

Inverted Bucket IInverrtted Buckett

Batch Processes: Steam Jacketed Kettle

Steam jacketed kettles are used for batch processing and are typically found in commercial food processing facilities. A steam jacketed kettle contains a liquid to be heated surrounded by an isolated jacket containing the steam (steam does not contact the fluid). Steam enters the kettle and its heat is then transferred to the liquid through the jacket wall and the condensate is discharged out the bottom. Steam Pressure to the kettle is controlled by the Steam Supply (Control) Valve. The steam trap is placed a minimum distance below the kettle to promote condensate drainage when low pressure or partial vacuum exists in the jacket of the kettle (14” is equivalent to 1/2 psi of head pressure).

Pressurized Steam enters Jacket of Kettle

Steam is contained in a “Jacket” which surrounds the Kettle and heats the contents.

Liquid to be heated

Condensate discharges from below

Steam Trap (not shown) placed a minimum distance of 14” below kettle to promote drainage of condensate under vacuum.

Continuous Process: Shell & Tube Heat Exchangers

Shell & Tube Heat Exchangers are used for continuous processes such as heating a continuous flow of water or other liquid. The Shell & Tube heat exchanger contains multiple tubes inside to optimize heat transfer to the process. In the majority of applications, the process liquid goes through the inside of the tubes and the steam surrounds the outside of the tubes and is contained within the shell area. The condensate that is formed from the condensed steam is discharged out of the bottom through a steam trap. Steam Pressure to the heat exchanger is con- trolled by the Steam Supply (Control) Valve. The steam trap is placed a minimum distance below the heat exchanger to promote condensate drainage when low pressure or partial vacuum exists in the shell of the heat exchanger (14” is equivalent to 1/2 psi of head pressure).

Shell contains the steam which surrounds the tube section in order to heat the liquid flowing thru it

Pressurized Steam enters Shell of Heat Exchanger

Single Tube shown for clarity

Cold liquid enters the tube section & the heated liquid exits

Tube Bundle of a Shell & Tube Heat Exchanger

Condensate discharges from below

Steam Trap (not shown) placed a minimum distance of 14” below Heat Exchanger to promote drainage of condensate under vacuum.

Shell & Tube Heat Exchanger

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