Once-Through vs Cooling Tower Water

An existing refinery cooling water system was to be expanded. There was a choice between once-through and re-use water, but the selection affected process cooler design and process operating conditions. An itemized check list was made to assist in the choice between the two cooling water systems. 

At the refinery the summer river water temperature rarely exceeded 70°F. Therefore, a design 

A secondary advantage of the lower river water temperature was discovered during a process evaluation period of engineering. Lower alkylating temperatures improve octane levels for HF and H2 SO4 processes. In fact, for sulfuric acid alkylation, refrigeration is necessary to achieve an acceptable octane product. 

Cooler water is also of advantage in the gas processing section. Gas recovery by absorption is improved with lower temperature at constant absorption oil circulation rates. Thus, additional light hydrocarbon may be squeezed from the dry gas, recovering C3+ that would otherwise become refinery fuel. 

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Maze, R.W. Practical Tips on Cooling Tower Sizing. Hydrocarbon Processing, February 1967, p. 123. Vahlsing, D.H. Once-Through vs Cooling Tower Water. Hydrocarbon Processing, July 1967, p. 167. 

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