Process Controllability Propane to Acrylic Acid design plant proses

101

8.6 Environmental Considerations

Acrylic acid is relatively non-toxic to bacteria and soil microorganisms. It is also miscible with water and is not expected to adsorb significantly in soil or sediment. When released into the atmosphere, it reacts to produce hydroxyl radicals and ozone which results in quick degradation. There is no bioaccumulation of acrylic acid as it readily biodegrades in water and has an atmospheric lifetime of less than one month. 18 Environmental concerns will be analyzed with respect to U.S. standards for pollution control. As there is no solid waste emitted from this process, the plant will meet the Federal Hazardous and Solid Waste Amendments HWSA under the Resource Conservation and Recovery Act RCRA. The problematic pollutants for this process in terms of air quality are CO x . Currently, the EPA’s Clean Air Act only regulates CO at the level of 35 ppm per hour. 19 As this process assumes that all CO is quickly oxidized to CO 2 , only trace amounts of CO may remain and this standard will easily be met. Although there is no present standard for CO 2 emissions, companies are required to obtain permits for construction and operation of their facilities from the EPA to insure compliance. 20 Additionally, CO 2 emissions are likely to be regulated in the future. The process may need to include a carbon capture and sequestration process if the plant is found to be above regulatory limits at a future date. The main impact on the environment is through the organic content in the wastewater streams. A cost for wastewater treatment has been included in the financial calculations and an off-site facility is assumed. 18 World Health Organization: International Programme on Chemical Safety. 1997. Environmental Health Criteria 191: Acrylic Acid. 19 Environmental Protection Agency 2012. National Ambient Air Quality Standards NAAQS http:www.epa.govaircriteria.html 20 Haggin, P. 2012. EPAs CO2 Regulation Upheld as Unambiguously Correct. Time. http:science.time.com20120628epas-co2-regulation-upheld-as-unambiguously-correct 102