Modifications pollution reduction

Pollution reduction measures within plants that include minimization of spills and modifications in the process through adaptation of cleaner technologies as alternatives to conventional technologies. 

POLLUTION REDUCTION THROUGH PLANT PROCESS MODIFICATIONS... 

Improving the cetane number by additives results in better engine behavior, as would be predicted by the combustion mechanisms in the diesel engine (noise reduction, better operating characteristics, particularly when cold). Nevertheless, concerning certain items such as pollution emissions, it may be better to obtain a higher cetane number rather by modification of the... 

Research Trends. Research since the late 1970s appears to have centered on further process modifications and optimization of conventional processes, reduction in pollution, evaluation of potentially more efficient processing technology, increased use of less expensive softwood sources to extend the available hardwood suppHes, and accommodation of recycled newspaper pulp (see Recycling, paper). 

Serious research in catalytic reduction of automotive exhaust was begun in 1949 by Eugene Houdry, who developed mufflers for fork lift trucks used in confined spaces such as mines and warehouses (18). One of the supports used was the monolith—porcelain rods covered with films of alumina, on which platinum was deposited. California enacted laws in 1959 and 1960 on air quality and motor vehicle emission standards, which would be operative when at least two devices were developed that could meet the requirements. This gave the impetus for a greater effort in automotive catalysis research (19). Catalyst developments and fleet tests involved the partnership of catalyst manufacturers and muffler manufacturers. Three of these teams were certified by the California Motor Vehicle Pollution Control Board in 1964-65 American Cyanamid and Walker, W. R. Grace and Norris-Thermador, and Universal Oil Products and Arvin. At the same time, Detroit announced that engine modifications by lean carburation and secondary air injection enabled them to meet the California standard without the use of catalysts. This then delayed the use of catalysts in automobiles. 

Biopolymers have diverse roles to play in the advancement of green nanotechnology. Nanosized derivatives of polysaccharides like starch and cellulose can be synthesized in bulk and can be used for the development of bionanocomposites. They can be promising substitutes of environment pollutant carbon black for reinforcement of rubbers even at higher loadings (upto SOphr) via commercially viable process. The combined effect of size reduction and organic modification improves filler-matrix adhesion and in turn the performance of polysaccharides. The study opens up a new and green alternative for reinforcement of rubbers. 

If the program continues and additional reductions are desired, more expensive and more complex projects begin to emerge (Phase II). These are often associated with equipment modifications, process modifications and process control and may include the addition or adaptation of auxiliary equipment for simple source treatment, possibly for recycle. This phase usually has little immediate ROI, and more inclusive approaches to assessing the economics of the operation (estimating costs for waste handling, long-term liability, risk) are needed to justify the continued pollution-prevention operation. 

It is not currently feasible to achieve a zero discharge of chemical pollutants from metal finishing operations. However, substantial reductions in the type and volume of hazardous chemicals wasted from most metal finishing operations are possible.8 Because end-of-pipe waste detoxification is costly for small- and medium-sized metal finishers, and the cost and liability of residuals disposal have increased for all metal finishers, management and production personnel may be more willing to consider production process modifications to reduce the amount of chemicals lost to waste. 

In a recent document [25] presenting techniques adopted by the French for pollution prevention, a new process modification for steam segregation and recycle in phosphoric acid production is described. As shown in Figure 9, raw water from the sludge/fluorine separation system is recycled to the heat-exchange system of the sulfuric acid dilution unit and the wastewater used in plaster manufacture. Furthermore, decanted supernatant from the phosphogypsum deposit pond is recycled for treatment in the water filtration unit. The claim was that this process modification permits an important reduction in pollution by... 

III. Reduction of Combustion-Generated Pollution by Combustion Process Modification... 

In case of a swirling bed combustor, design modifications required for pollutant abatement were recornmended from this reactor network analysis. These changes in design based on the modeling predictions proved to be efficient in CO reduction. 

Cost/Benefit Analysis Since any change or modification in the process requires additional capital, operation, and maintenance cost, a cost analysis must be included to help management make informed decisions. These factors may include cost avoidance, enhanced productivity, and decreased liability risks from the pollution prevention effort. Federal and state agencies have provided matching grants to small industries to implement source reduction programs. 

In respect of the severe regulations imposed, the motor car manufacturers have decreased considerably the NOx emissions from their vehicles. Initially this was by a modification of the engine s combustion chamber. More recently these measures have proved less than sufficient and so to prevent pollution an exhaust after-treatment has become necessary. With this in mind, several technologies have been developed in order to decrease the harmful NOx emissions. One of which is selective catalytic reduction by hydrocarbons (HC-SCR). An enormous amount of catalytic materi tls have now been developed [1] and an appropriate choice would seem to be supported noble metal catalysts [2]. A high activity is generally observed at low temperature while the efficiency remains little affected by water. The effects ... 

Since 1970 substantial reductions in emissions of pollutants from passenger cars already were achieved in the countries of the European Community (EC) HC emissions were reduced by 60%, CO by 70% and NO by 30% (2). These reductions were obtained by engine modifications. 

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