Chemical engineering is the discipline in which knowledge of mathematics, physics, chemistry and biology, gained by study, experience and practice, is applied with judgement to develop economic and safe ways of converting raw materials into more useful products to benefit mankind. It is devoted to the chemical, physical or biological transformation of matter or energy into useful forms, economically and safely without compromising the natural environment.
Petroleum refining processes are those chemical engineering processes and other facilities used in petroleum refineries (also referred to as oil refineries) to transform...
HydrodesulfurizationLast Updated on 2013-12-15 23:43:02Hydrodesulfurization (HDS) or Hydrotreating is a catalytic chemical process widely used to remove sulfur compounds from refined petroleum products such as gasoline or petrol, jet fuel, diesel fuel, and fuel oils. One purpose for removing the sulfur is to reduce the sulfur dioxide emissions resulting from using those fuels in automotive vehicles, aircraft, railroad locomotives, ships, or oil burning power plants, residential and industrial furnaces, and other forms of fuel combustion.
Another important reason for removing sulfur from the intermediate product naphtha streams within a petroleum refinery is that sulfur, even in extremely low concentrations, poisons the noble metal catalysts platinum and rhenium in the catalytic reforming units that are subsequently used to upgrade the of the naphtha streams.
Hydrogenation of the sulfur compounds results in the formation of undesirable,... More »
AERMOD Last Updated on 2013-10-05 15:00:30AERMOD is the latest generation air dispersion model designed for short-range (up to 50 kilometers) dispersion of air pollutant emissions from stationary industrial sources. It is a steady-state plume model incorporating dispersion based on planetary boundary layer (PBL) turbulence structure and scaling, and it accomodates surface and elevated emission sources as well as simple or complex terrain.
As of December 9, 2005, the U.S. EPA designated AERMOD as the preferred model to be used for compliance with any federal and state air pollution dispersion modeling requirements. As of November 9, 2006, AERMOD completely replaces the previous preferred model known as the Industrial Source Complex (ISC) model.
The AERMOD system integrates three modules:
A steady-state Gaussian dispersion model designed for short-range dispersion of continuous emissions from stationary... More »
National Center for Atmospheric ResearchLast Updated on 2013-08-21 02:53:16The National Center for Atmospheric Research (NCAR) is a non-governmental institute, based in the United States, whose stated mission is "exploring and understanding our atmosphere and its interactions with the Sun, the oceans, the biosphere, and human society."
NCAR's flagship Mesa Laboratory is located in the outskirts of Boulder, Colorado, in a dramatic complex of buildings designed by the renowned architect I. M. Pei. The site is maintained as a nature preserve.
The Mesa Laboratory includes science exhibits, an educational resource center, a library, and art galleries all of which open to the general public.
NCAR is headquartered in Boulder, Colorado, with most activity taking place on three campuses:
NCAR Mesa Laboratory: in the southwest outskirts of Boulder Foothills
Laboratory and Center Green Campus: in northeast Boulder Research
Aviation Facility: at... More »
NitrateLast Updated on 2013-08-11 10:09:48Nitrate is a polyatomic ion having a molecular formula NO3- and molecular mass of 62.0049 grams per mole. This ion is the conjugate base of HNO3, its geometry consistng of one central nitrogen atom surrounded by three identically-bonded oxygen atoms in a trigonal planar arrangement. The nitrate ion carries an electrical charge of minus one, arising from a combination formal charge in which each of the three oxygen atoms carries a fractional two thirds charge, whereas the nitrogen atom carries a plus one charge, all these adding up to minus one formal charge of the polyatomic nitrate ion. This atomic arrangement is often invoked as a classic example of chemical resonance. Similar to the isoelectronic carbonate ion, the nitrate ion can be represented by resonance structures.
Nitrate is a very important chemical soil amendment responsible for a major portion of the agricultural... More »
South Coast Air Quality Management DistrictLast Updated on 2013-08-11 09:47:11The South Coast Air Quality Management District (SCAQMD), formed in 1976, is the local governmental agency in California which is responsible for regulating stationary sources of air pollution in the area depicted on the adjacent map. That area includes all of Orange county and the urban portions of Los Angeles, Riverside and San Bernardino counties. The main office of the SCAQMD is located in the city of Diamond Bar, California.
The area encompassed by the SCAQMD amounts to about 10,750 square miles (27,840 square kilometres) and is the second most populated area in the United States. This area has a severe problem with smog and the SCAQMD has been a leader in the nation's efforts to reduce air pollution emissions.
The SCAQMD develops, adopts and implements an "Air Quality Management Plan" for bringing the area into compliance with the clean air standards... More »
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