Air Pollution in the Nitric Acid Plants - Book Report/Review Example

Air Pollution In The Nitric Acid Plants Introduction The benefits of industrialization continue to be enjoyed by all through the production and manufacturing of different forms of products that are needed in making the day to day life of people easier. But as we enjoy these benefits, one thing that cannot be denied is that there are cases and instances that industrialization becomes a nuisance to the ecosystem and for that matter the environment. One of the commonest ways by which industrialization has posed challenge to the ecosystem is through the problem of pollution. This is because in most of the activities of these industries, highly sophisticated raw materials, most of which are harmful when exposed to the natural environment are used (Durilla 21). In this paper, the specific pollution problem of air pollution is addressed from an industrial perspective, where the nitric acid manufacturing industry is reviewed. The paper identifies key challenges that the industry poses in terms of air pollution and how the problem can be contained by adherence to basic environmental regulations and statutes. The industry and processes that lead to air pollutant emission As showed in fig. 1, the production of nitric acid by a typical nitric acid plant involves two major catalytic combustion stages, the last stage of which is known as the tail gas stream. European Commission (7) notes that the second stage of the production process, rather than the first is connected to several forms of pollutant emission into the atmosphere. For example in the first stage, there is the reaction of ammonia and air, which combusts under pressure on rhodium platinum gauze to give off nitric oxide. There is then the cooling of the process gases using series of heat exchangers, boilers and steam super-heaters (Durilla 4). At this point, there is reaction with air and water in the oxidizing absorption plant to lead to formation of nitrogen dioxide and then nitric acid in subsequent process. This means that the first stage focuses entirely on the production of the needed material. Unfortunately though, the process does not automatically end here as there is a toxic effect that takes place at the tail gas stream of the formation of nitrogen dioxide, leading to air pollutant emission. Fig 1: Flow diagram of typical nitric acid plant Source: EPA (2) Major pollutant emitted and data on their quantities According to the EPA (7), the major pollutant emitted from the nitric acid production process is nitrogen oxide (N20). These nitrogen oxides actually come into the process of production as byproducts of the process stream, a reason they are considered as industrial process emissions (EPA 7). In terms of the quantity of pollutant emitted, the EPA notes that this is a variable that is dependent on a number of factors including “combustion conditions in the oxidizing unit, catalyst compositions, catalyst age, and burner design” (7). This notwithstanding, the agency has since 2010 used a standardized formula for determining what uncontrolled N20 emission from nitric acid plants hould be by using a GHG inventory. According to the inventory, the acceptable level is 9kg N20 per metric ton of HNO3. Through this inventory, an uncertainty bound for default factors have been produced to determine low and high vales of emission as shown in the table below. Fig 2 Default N20 Emission Factors Source: EPA (8) History of Air Pollution Issues in the Industry The nitric acid production industry is one with a long history of air pollution issues. According to Durilla (13), the major issue that industry players had to deal with before 1996 when the Technical support Document (TSD) for proposed GHG Reporting Rule was produced was the problem of measuring how much of nitrogen oxide was too much harmful for the environment and how much was not. There was also the issue of identifying specific effects of nitrogen acid on man and plants. Another important issue that emerged from history was ways of controlling the emission as more empirical findings were made on ways of measuring up levels harmful emission. Today, much of the issues that were posed in history have been adequately addressed. For example, fig 2 gives vivid outlay of the emission quantities that may be acceptable and those that will not be. Seales (1973) also noted that when there is man’s exposure to nitrogen dioxide at levels of 300 parts per million, this would lead to fatal broncho-pneumonia. Leaf damage and decreased fruit yield is also the effect that plants face when exposed to levels below 1 p.p.m of nitrogen dioxide. On control techniques and measures, the EPA rejoices over discoveries made about the use of control technologies curtailing the effect and exposure of pollutants from nitric acid manufacturing plants (2). New Source Performance Standard requirements for the industry The EPA notes the essence of having a standard for form and pollutants under the new source performance standards requirements for the industry so as to ensure that both direct and indirect causes that contribute significantly to air pollution which may be noted as being danger to public health and welfare will be identified and curtailed (Jackson 8). In effect, the NSPS lays out new standards for new nitric acid plant units (NAPU), where new NAPU is defined as NAPU which had its construction, modification or reconstruction after October 14, 2011. This means that emphasis is on new facility producing weak nitric acid either under pressure or by use of atmospheric pressure process (Jackson 9). For these new NAPUs, pollutants are defined as NOx, which reacts with the atmosphere in the formation of particulate matter and ozone (Jackson 10). N2O, which is also considered as greenhouse gas (GHG) is also covered as pollutant. For industry players to stick to standards, they are expected to produce NOx at limits of 0.5 per ton of 100 percent nitric acid produced as a 30 operating day emission rate. There are however exceptions to this in events of startup, shutdown, and malfunction. Examination of Recent Activity in the Industry Recently, much progress has been seen by industry players when it comes to the control of pollutant emission from nitric acid plants. For example, studies conducted by European Commission (3) showed that there is a new course of action where the industry players have adequately identified their place in the fight against air pollution, knowing that they are stakeholders for change. What is more, industry players have admitted to the fact that air pollution resulting from missions from nitric acid production is highly consequential and must therefore not be allowed to exist at all. It is therefore common to find major nitric acid plants being connected to major technologies that act through various stages and processes including absorption, adsorption and catalytic combustion to remove nitrogen oxides at the very production stage so that the exposure of these into the environment do not occur at all. Conclusion This has been a very useful academic discussion that has adequately exposed the merits and demerits of the nitric acid producing industry. To a large extent, the industry has been found to be a generally useful one whose production turnaround is needed to make other industries run successfully. However, in the course of the production of nitric acid, key gaseous byproducts, which have come to be known as tail gas stream, pose major challenge to the environment as its uncontrolled emission leads to pollution of the air. But for a long time in history, there has been different approaches attempted at solving the situation. With new discoveries made with the use of emerging technologies for reducing air pollution from nitric acid plants, it can be concluded that the future is more hopeful than a treacherous one when it comes to the nitric acid production industry and its relation to greenhouse gas emission. Works Cited Durilla, Mike, 2009. “NOx and N2O Control in Nitric Acid Plants,” Environment Management. Air and Waste Management Association. November 2009 European Commission. Support for the Development and Adoption of Monitoring and Reporting Guidelines and Harmonised Benchmarks for N2O Activities for Unilateral Inclusion for the EU ETS for 2008-12. 2008. Web. February 27. http://ec.europa.eu/environment/climat/emission/pdf/benchmarking/entec_study_2008.pdf Jackson Lisa P. New Source Performance Standard: 40 CFR Part 60. 2010. Web. February 28, 2014 U.S EPA. AP-42: Available and emerging technologies for reducing greenhouse gas emissions from the nitric acid production industry. 2010. Web. February 27, 2014 Read More