An effective Air Pollution Control Plant in any industry should:
A) Control the working environment to protect the workers and the machines from pollution hazards.
B) Control the emission limits of the exhausts as per the set norms of the Pollution Control Boards and avoid unrestricted discharge of solid and gaseous pollutants to the atmosphere.
The net results of the above features of Air Pollution Control are:
1) Healthy working atmosphere keeps sound health of workers and machines leading to their quality output.
2) Avoid the far-reaching effects of pollution problem on people and the other living things, vegetation, buildings and structures surrounding the industries.
3) Assists in keeping a balance in the ecological system.
It is always suggested that the production / process equipment manufacturers should consider the dust / fume generation aspects seriously while designing their equipment and should try to minimise the same. Unavoidable dust and fume generated in the process should be controlled at the source of generation through the system of capture, extraction, conveying, collection and finally proper disposal or recycle. In some cases fine dusts are suppressed on the mother material with the help of fine mists/ fog.
Design and selection of particular equipment for any application requires a clear understanding and thorough knowledge of the characteristics of the problem.
Next comes the System Design, which plays the most important role in the performance of the Air Pollution Control Plants. Wrongly designed systems never improve the environmental conditions, even if we use highly efficient collecting equipment. In an unbalanced Dust Extraction System suction at some dust generation points are more than the requirement while the other points are found starving allowing the generated air borne dusts to escape in the surrounding atmosphere.
Many large polluting industries have some Pollution Control Plants installed already but could not be used properly either for deficiency in equipment design or deficiency in the system design or both. In this perspective the Original Equipment Manufacturers in this field have big roles to play. They are required to study the problems of different plants seperately and analyse them critically. Using their experience they should give their suggestions only when they are confidant of the solutions. If needed, they may use economical pilot plant studies. Improvisation and innovative ideas are the requirements of the day. Equipment being manufactured and supplied by them should be of the latest design developed through R&D activities overcoming the known weaknesses. In fact, the latest designs of equipment are simple and versatile.
Results of many new plants are not satisfactory either for the improper selection of equipment/improper equipment design or the system design not made properly. In some plants with Bag Filters as dust collectors, to make up the deficiency in the design of filter bag cleaning mechanism the commissioning engineers of the plant suppliers were found to reduce the filter bag loading (filtering velocity) by reducing the damper opening at fan inlet / outlet. This reduces the suction of dust laden air quantity at the dust generation points as a result of which the dust capturing velocity reduces and the generated dusts spread in the working zone. Any dust, if enters the ducting through hoods also settles in the ducting for the less conveying velocity, slowly choking the system.
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The basic idea is to achieve the best possible stable performance of the existing plants by incorporating very little modifications and utilizing all the working accessories already available in the existing equipment (e.g. Bag Filter / ESP / Scrubber) based on the technological developments came through R&D activities.
Proper interlocking among the control equipment can also be made with very little investment so as to run the plants practically in totally Auto Mode continuously within a suitable pressure differential so as to achieve their best possible stable performance.
However regular checking of some parts of the equipment as well as checking of the availability of the required utilities should be carried out so as to minimise maintenance shutdowns. Facility for on-line maintenance can also be arranged so as to avoid any shutdown.
Some industries lack proper operation and maintenance practices. Hence, workers and operators require proper guidance from experienced – practical personnel for proper operation and maintenance of the plants so as to achieve their best possible stable performance.
We often talk about green technology or environment friendly technology. This is basically the concept of generating less pollution at the point of generation rather than capturing them or controlling them after they are generated in large quantity.
A close cooperation between the main equipment designer and the experts in the field of Air Pollution Control can be highly beneficial.
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