Dr VS Rajan, Vice President – Filter Products, Supreme Nonwoven Industries Pvt. Ltd.
According to Dr VS Rajan, Vice President – Filter Products, Supreme Nonwoven Industries, all new projects are adopting work practices to comply to dust emission levels of below 10 mg/Nm3.
Bag filter is a key component of any cement plant. How is the regulatory requirement changing in terms of permitted emissions?
New regulations have become stringent on suspended particulate matter (SPM) and gaseous pollutant (SOx and NOx) levels. The present limit, which is set at 30 milligrams per cubic metre (mg/Nm3), is very hard on many cement companies as their present air pollution dust collector system is still of the 80s and 90s design. Same goes with electrostatic precipitators (ESPs), which are built for about 50 to 75 mg/Nm3 levels. All these are need to be revamped for the new emission norms.
At Supreme Nonwoven Industries (SNIPL), as a media designer and a manufacturer, we are making great strides in bringing new filter products that are more compact to arrest fine particles. This is achieved by use of special fibres, newer surface treatment and adopting newer production practices. By this way, the dust emission levels below 10 mg/Nm3 is possible.
How different are the Indian environmental requirements compared to other countries?
As far as cement industry is concerned, being the second largest in the world in terms of production, we are well ahead in our regulatory standards. The Indian cement industry has already taken the first step to bring it down to 30 mg/Nm3. However, in a couple of years, this will be brought down to 10 mg/Nm3. All new projects are adopting work practices for complying to dust emission levels of below 10 mg/Nm3.
Is there a competition in the cement industry between a ESP and a bag house?
It is now a known fact that the cement industry cannot afford to have ESPs not only for delivering dust emission levels below 10 mg/Nm3, but also aiming to regain their raw material and product. Hence, all new projects are with bag filters with low emission levels. Even the old ESPs in some companies have come for retrofitting into bag filter systems.
How much of your equipment are manufactured in India v/s imported?
Most of our filter media is 100 per cent indigenous material. Only some special fibres that are not produced in India are imported. We are maintaining surplus production capacity that helps to bridge the growing demand year after year. Our production capacities are always maintained a little above the present market demand. Export is one key area we may like to focus on. This is not only for the business growth, but to reach our technologies on foreign soil.
Do you have any presence in the most critical high temperature application?
There are two high-temperature operations in the cement industry: one is the kiln gas filtration and the other one is clinker cooler application. The latter is still an ESP in many industries and that will have to come to bag filter soon. In these applications, the filter bag’s performance to deliver long bag life with low DP and emission are the main benchmark for success.
(With inputs from Sachin Deshpande, General Manager - Filter Division, Supreme Nonwoven Industries Pvt Ltd)