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Consider The Effects Of Global Warming

Sept. 20, 2021
We won’t recognize chemical processing by 2100

Supply chain disruptions from hurricanes lead to multiple economic impacts as a 2017 fact sheet from the American Petroleum Institute explains: “When a hurricane disrupts refinery or pipeline operations, the combination of an immediate loss of gasoline and diesel production and a lack of demand for crude can result in a two-tier market — the price of fuel can rise and the price of crude can fall.” Of course, other ramifications result, including the need to clean up the devastation.

Skeptics largely have given up arguing against the reality of global warming after Hurricanes Katrina, Harvey and Sandy. The Union of Concerned Scientists says the situation only will get worse: https://bit.ly/3k0HYhf. “It’s a forecast nightmare,” cautions Kerry Emanual, a professor of atmospheric science at the Massachusetts Institute of Technology. “If a tropical storm or Category 1 hurricane develops into a Category 4 hurricane overnight, there is no time to evacuate people.” (See: “What We Know About Climate Change and Hurricanes,” New York Times, August 29, 2021.) Logically, this applies to other natural disasters such as tornadoes, wild fires, etc. Warnings may provide only a few hours to prepare instead of two to three days.

Besides causing catastrophic events, global warming certainly will economically impact chemical production. Let’s first consider the effect of rising humidity on cooling.

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I was concerned with the cooling towers at the plant I work at in Ohio. Using an online program available from SPX Cooling Technologies, www.spxcooling.com/water-calculator, I was able to show the effect of rising humidity. Our current design specification is supply — 83°F; return — 93°F with a wet bulb temperature of 78°F. I assumed a water flow of 10,000 gal/min. Unfortunately, the program is limited to a wet bulb temperature of 90°F but the calculations were revealing. The minimum available supply temperature jumped to 94°F and the return temperature rose to 114°F. The water losses increased by 4%; evaporation increased to 114 gal/min from 110, and blowdown to 57 gal/min from 55. Of course, the loss from drift remained the same; however, atmospheric research on global warming doesn’t devote much attention to wind changes.

Projecting SPX’s data, I estimate that at a wet bulb temperature of 100°F the minimum product temperature would be at 133°F!

These changes seem modest except for two facts: 1) much of U.S. oil refining takes place along the Gulf Coast (83.5% of the largest refineries are located there); and 2) 133°F is very warm for more delicate chemical products. (I assumed a 10°F minimum approach for heat exchangers.)

As we saw with Hurricane Harvey in 2017, weather can disrupt the U.S. economy for months. Economic forecasters reckon the 3rd-quarter gross domestic product (GDP) dropped by 0.2–0.8% then, a stark contrast to the 3.7% growth predicted before Harvey. If forecasters are right, this economic damage will accelerate with rising temperatures. One conservative estimate is a 1.8% impact on U.S. GDP by 2100; others are higher.

Warmer ambient temperatures directly affect some process operations. As I recall from my experience with fermentation at Anheuser-Busch, sterilized raw materials were stored at temperatures only a little shy of the minimum product temperatures. So, fermentation and most similar processes would have to go to much more expensive refrigeration.

The impact will go far beyond just products; most conventional refrigeration will become useless. Global warming also will affect key equipment. For example, water-cooled air compressors are designed for a maximum temperature of about 120°F — some even lower, 95°F.

Other effects of global warming bear consideration. Storm water controls in our industry generally mandate separating polluted runoff from ordinary runoff such as that from parking lots. Current designs, which date to the 1970s when regulations about separation were created, were developed based on a 24-hour rainfall event from a once-every-25-year storm. Now, 100-year floods are happening every five years. Intensities are unpredictable and may reach a wastewater manager’s worst nightmares. Few regulators are willing to risk the political backlash from providing specific standards. They won’t tell you what you should use for your design standards but will hold your plant accountable if it floods a river with toxic chemicals! It falls to industry to create safe wastewater-handling processes to avoid situations like being banned from sending streams to a municipal wastewater facility.

About the Author

Dirk Willard | Contributing Editor

DIRK WILLARD is a Chemical Processing Contributing Editor.

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