Water is used throughout refineries to heat fluids during the refining process and to cool various production units while they perform refining functions. In some units, water temperatures reach more than 140 degrees Fahrenheit!
To stay green and conserve resources, we continually reuse water. To reuse water, we have to send it to the cooling towers. The cooling process causes evaporation. When the vapors mix with the airstream, harmless steam clouds form at the top of the stacks.
A number of factors can affect the size and color of the steam cloud. For example, the hotter the water is before cooling, the more evaporation needed to bring the temperature down so a larger "cloud" forms. On a humid day, when there is already a lot of moisture in the air, the water can’t be absorbed as quickly so the "clouds" are darker and look heavier.
Occasionally, water vapor rising out of the refinery cooling towers is carried by the wind and condenses as a mist that settles back to the ground. When the mist bakes in the sun it can leave water spots and minerals behind that you may see on surfaces like cars.
Every facility is closely monitored by federal, state, and local agencies and we work hard to exceed air quality standards, and we are continually improving our processes. Our track record of outstanding compliance speaks for itself and we will continue to uphold our commitment to efficient and environmentally-friendly operations.