Solvent emission, reduction

VOC Emissions Reduction Approach. The Rule 66-type approach focuses on solvent composition further developments have led to regulatory approaches that emphasize overall VOC emission reduction. Even though the more reactive solvents react near their emission point, all VOC compounds eventually react to form ozone pollution. This may occur some distance downwind, increasing ozone levels in areas which have low artificial emissions. 

Top Goats. The selection of a top coat depends on cost, method of appHcation, and product use and performance requirements, among other factors. As a result of increasingly stringent air quaHty standards and increased solvent costs, approaches to reduction of solvent emissions are being sought. 

Conventional nitrocellulose lacquer finishing leads to the emission of large quantities of solvents into the atmosphere. An ingeneous approach to reducing VOC emissions is the use of supercritical carbon dioxide as a component of the solvent mixture (172). The critical temperature and pressure of CO2 are 31.3°C and 7.4 MPa (72.9 atm), respectively. Below that temperature and above that pressure, CO2 is a supercritical fluid. It has been found that under these conditions, the solvency properties of CO2 ate similar to aromatic hydrocarbons (see Supercritical fluids). The coating is shipped in a concentrated form, then metered with supercritical CO2 into a proportioning airless spray gun system in such a ratio as to reduce the viscosity to the level needed for proper atomization. VOC emission reductions of 50% or more are projected. 

The Solvent Emissions Directive was adopted in March 1999 by the European Council of Ministers and should be implemented by member states within two years. The adhesives industry uses about 130,000 tonnes of solvents in its products annually and has a key role to play in meeting the Directive s targets. The main impact of emissions reduction will be on adhesives coaters because the adhesive film forms through the evaporation of solvent. For adhesives manufacturers, the main issue is the reduction of fugitive emissions. Both oxidation and recovery are well proven abatement techniques. BELGIUM EUROPEAN COMMUNITY EUROPEAN UNION WESTERN EUROPE... 

Direction of innovation tfrom the standpoint of market actors - 6al Automotive manufacturers substantiate the reduction of solvent emissions by water-based and powdered coatings on the basis of emission statistics. However, the automotive manufacturers state the improvement of the surface quality with the simultaneous improved cost-effectiveness of procedures as the decisive criterion for successful innovation. 

Hazardous Solvent Source Reduction Environmentally Benign Chemistry Aims for Processes that Don t Pollute Options For Reducing Greenhouse Gas Emissions in die Chinese Industrial Sector... 

Emission and Economic Advantages. The use of Hycar 2100R series polymers offers a significant reduction in solvent emission over conventional 40% solids system (by wt.). An 83% reduction in solvent emission (figure 1) results when the 80% solids Hycar system is used. Further reduction is obtained for 90% and 100% solids systems. The solvent content of the 90% solids system is so low that neither incinerator nor heat exchanger may be needed - a very good possibility for smaller PSA converters. 

The persistence of ozone pollution may result in additional emission restrictions for industry. Because of aggressive emissions reduction programs in the past, industrial emissions represent a minority share of total emissions, typically in the range of 15—20%. Despite this success in reducing emissions, it is hkely that large industrial emission sources, including industrial solvent emissions, will have additional controls imposed because those plants still represent the easiest targets to obtain further reductions. 

For ICP-OES-MS (inductively coupled plasma-optical emission spectroscopy-mass spectroscopy) work, the desolvator will remove oxide and hydride polyatomic ion interferences, i.e. ArO+ is reduced 100 fold, which allows for improved detection of Fe. The solvent loading reduction is caused by volatiles passing through the walls of a tubular microporous Teflon PTFE membrane. The argon gas removes the solvent vapour from the exterior of the membrane. Solvent-free analytes remain inside the membrane and are carried to the plasma for atomisation and excitation. 

Rule 66 provides a simple reactivity scale. It requires an 85% reduction of solvents emissions from various industrial application if these solvents are photochemically reactive. Photochemically reactive solvents contain ... 

Mixed solvents can be difficult to recover. If they are kept separate, they can be reclaimed by distillation on site. The capital investment required is paid back by the reduced need to buy new solvent. In Germany completely enclosed vapor cleaners give 99% reduction in solvent emissions.198 After cleaning and draining, the air-tight chamber is evacuated, the solvent vapors are captured by chilling and adsorption on carbon. When a sensor shows that the solvent is down to 1 g/m3 the vacuum is released so that the lid can be opened. 

Catalyst monoliths are also effective in the control of air pollution from stationary sources. They have been used for many years to oxidize hydrocarbon vapors in the vent streams from chemical plants and to reduce solvent emissions from printing and cleaning processes. More recent applications include CO removal from gas turbine exhaust and the selective catalytic reduction of NO in flue gas. Performance curves for the oxidation of various compounds over a Pt/Al203 catalyst are shown in Figure 10.5, where the conversion is plotted against the feed temperature. The reactors operate adiabatically, and the exit temperature may be 10-100°F above the feed temperature. At first, the conversion increases exponentially with temperature, as expected from the Arrhenius relationship. The decrease in slope... 

A survey measurement of the total carbon emission over the full foundry process is given in Figure 4.9. The data show that the vegetable-based solvents partially result in a shift of emissions from the core-making area to the finishing area. Nevertheless an overall reduction of 17 % carbon emission reduction is reached. 

Cost Effective Solvent Management, Cost Effective Reduction of Fugitive Solvent Emissions, Cost Effective Separation Technologies for Minimising Wastes and Effluents, Monitoring VOC Emissions Choosing the Best Option. 

Not all the VOCs enter the air, however, since remedial efforts, such as absorption and solvent reclaim, after-burning of solvents, flic use of bio-filters, result in emission reduction. 

Neverflieless, it is still evident fliat limitation of solvents, VOCs, reduction in varnishes and coatings may help in reducing emissions. 

In spite of considerable reductions in the use of organic solvents, the worldwide-adopted ozone values in the troposphere are not being attained. It is crucial to apply consistent measures worldwide to reduce solvent emissions. 

As part of society s increasing drive to minimise the impact it has upon the environment, we are now starting to see solvents managed responsibly by their users, with the consequence that emissions to the environment will be minimised. A result of this will be a decrease in the overall consumption of solvents over the next decade. Behind this simple trend lies an extremely dynamic situation in order to achieve the desired controls, some solvents will play an increasingly important role in state of the art, efficient systems whilst others will decline. Engineering controls (abatement systems) will be a part of this process of emission reduction along with reformulation to more efficient solvents and the development of new, high efficiency solvents suitable for use in low VOC materials. 

In principle, BAT(NEEC) and RACT offer the user flexibility in choosing an emission reduction strategy -choice between a variety of end-of-pipe abatement techniques, low solvent technologies, waste minimisation or any combination of these. It recognises that the most appropriate solution will vary from one application to another with size, product quality required and the age and location of a plant. 

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