Industrial emission controls

Governmental regulations and technological innovations have helped reduce the amount of environmental pollutants and GHGs emitted into the environment as by-products of industrial manufacturing.

Background

Since the began in the mid-nineteenth century, factories using combustion to power machinery manufacturing products have released chemicals detrimental to the environment in their emissions. By the twentieth century, power plants generating energy through burning fuels such as coal and natural gas added to this pollution, and industrial accelerated climate change. Motivated by economic, legislative, and environmental incentives, many industry operators sought ways to control industrial emissions. Engineers and scientists innovated and devised technology or methods to minimize, remove, convert, or store chemicals emitted during industrial combustion activities.

Industrial Emissions and Control Strategies

Turbines, boilers, generators, engines, and furnaces powered by burning fuels release GHGs produced during combustion. Emissions frequently associated with industries include nitrogen oxides, sulfur dioxide, carbon dioxide (CO₂), and methane. The US Environmental Protection Agency identified petrochemical, ammonia, aluminum, steel, iron, and cement manufacturers as emitters of large amounts of GHGs.

Political and social demands to reduce emissions resulted in many industry leaders evaluating how to alter production methods and technology in order to satisfy laws limiting emissions while not experiencing profit losses. Intergovernmental Panel on Climate Change (IPCC) reports discussed how to control industrial emissions, recommending industry managers seek control strategies and technology appropriate for manufacturing processes and fuels their factories utilized.

Carbon Capture and Storage

Industries have successfully controlled emissions with carbon-capture-and-storage (CCS) methods by securing carbons released during combustion and then compressing and sequestering them in remote areas, usually underground, distant from the Earth’s atmosphere. CCS is especially effective for minimizing CO₂ released in emissions from petroleum, iron, cement, and ammonia industrial processes and refineries.

Norwegian industries were early users of CCS because Norway’s government began taxing carbon emissions in 1991. Norwegian engineers and scientists created CCS technology and procedures to store CO₂ in sandstone approximately 1,000 meters beneath the North Sea. Starting in 1996, the Norwegian industry StatoilHydro sequestered almost one million metric tons of carbon emissions annually.

Experts emphasized CCS technology is essential to achieve projected emission reductions by 2100. Researchers collaborated on CCS projects. Scientists experimented using chemicals to enhance CCS effectiveness and burning to power equipment used to capture CO₂. They also used to capture carbon.

Scrubbers

Scrubber technology cleans exhaust and emissions from industrial sources by removing particulates from acidic gases. A typical scrubbing procedure results in chemicals in emissions being altered, sometimes undergoing reactions to transform into other compounds, or lessening their strength.

Scrubbing equipment designs incorporate a tank and recirculation system cycling liquid into the presence of emissions. The basic particulate scrubbing process involves the swift movement, from 45 to 120 meters per second, of emissions inside a tank constructed from fiberglass or metals that will not corrode. In this vessel, a liquid, often water, serving as the scrubber impacts the fast-moving emissions and transforms into small drops that absorb particles in emissions.

Engineers designed scrubbers to meet specific industrial needs. Scientists identified chemical solutions, including chlorine dioxide, hydrogen peroxide, sodium chlorate, and sulfuric acid, effective as scrubbers to minimize sulfur oxides, nitrogen oxides, and heavy metals, such as mercury, in flue gas emissions.

Filtration

Industrial emissions can be controlled by filtering contaminants produced during combustion. Filtration technology consists of an insulated metal chamber, usually made from stainless steel or an alloy, and mesh filters, mostly constructed with copper, silicon, or aluminum. Tanks store water before and after filtration. Sprayers and pipes transport water during filtration.

Water and temperatures control industrial emissions during filtration. Inside the chamber, sprayers coat water that has been cooled to 2° Celsius in an adjacent refrigerator tank on one or more mesh filters near the top of the chamber prior to hot emissions rising beneath the filter in the chamber. The dripping water hits the emissions, cooling them, and capturing particulates or liquefying such gases as sulfur dioxide and CO₂ when they reach the filter. The water containing particulates and gases is expelled into a dump tank.

Neutralization and Absorption

Some industrial emissions are managed by neutralizing them. Researchers innovated methods to extract toxic chemicals prior to combustion. Engineers developed technology to impede nitrogen oxidization during combustion. In selective catalytic reduction (SCR), the reaction of ammonia with flue gases, aided by the use of a catalyst such as tungsten oxide, breaks nitrogen oxides into nitrogen molecules and water. SCR effectively reduces emissions by 80 to 90 percent but is costly due to catalyst expenses.

Fluidized bed combustion (FBC) keeps nitrogen oxides from being produced because chamber temperatures are lowered to 750° to 950° Celsius by water tubes in the bed absorbing heat. FBC control methods used when burning coal achieve 80 to 90 percent reduction of sulfur oxides. Various flue gas desulfurization (FGD) methods utilize chemicals or minerals such as limestone that absorb emission contaminants, particularly sulfur dioxide.

Context

Images of smoke rising from industrial parks are often used to symbolize global warming. Endeavors to control industrial emissions exemplify international focus on enhancing and promoting the use of clean technology, particularly due to the expansion of industry because of economic incentives to produce more goods and energy to support expanding populations. Legislation such as the US Clean Air Acts (1963-1990) outlined requirements for industries to control emissions. The addressed industrial emissions control and suggested reductions. As global warming worsened into the twenty-first century, governments worldwide, such as the European Union, revised limits previously set for GHGs produced by industries.

Many industrial leaders recognized their environmental responsibilities and willingly limited emissions from factories and acquired updated equipment, trained operators, and enforced stricter procedures to minimize the impact of industrial emissions on climate change. Other industries, however, continued to release excessive GHGs because of apathy, ignorance, or inability to afford or attain access to emissions control technologies.

Key Concepts

• capture: to secure and contain harmful particles and chemicals
• combustion: the burning of fuels to produce energy
• emissions: gases and particulates released by industrial and other processes
• filtration: separation or removal of contaminants from emissions
• industrial: related to large-scale manufacturing or energy production
• neutralization: elimination of harmful characteristics or properties to render contaminants benign
• scrubbers: liquids that remove pollutants from emissions
• sequestration: isolation of hazardous emissions to prevent them from polluting the atmosphere

Bibliography

Intergovernmental Panel on Climate Change. Climate Change, 2007—Mitigation of Climate Change: Contribution of Working Group III to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Edited by Beth Metz et al. New York: Cambridge University Press, 2007.

Maroto-Valer, M. M. Mercedes, John M. Andrésen, and Yinzhi Zhang. “Toward a Green Chemistry and Engineering Solution for the US Energy Industry: Reducing Emissions and Converting Waste Streams into Value-Added Products.” In Advancing Sustainability Through Green Chemistry and Engineering, edited by Rebecca L. Lankey and Paul T. Anastas. Washington, DC: American Chemical Society, 2002.

"Setting Emissions Standards Based on Technology Performance." US Environmental Protection Agency, 6 Aug. 2024, www.epa.gov/clean-air-act-overview/setting-emissions-standards-based-technology-performance. Accessed 17 Dec. 2024.

Wald, Matthew L. “In a Test of Capturing Carbon Dioxide, Perhaps a Way to Temper Global Warming.” The New York Times, March 15, 2007, p. C3.

Wilson, Elizabeth J., and David Gerard, eds. Carbon Capture and Sequestration: Integrating Technology, Monitoring, and Regulation. New York: John Wiley and Sons, 2007.