Re-rolling mills operating at poor thermal efficiency: Study

Gagandeep Singh

Tribune News Service

Jalandhar, May 31

A study conducted by the Punjab State Council for Science and Technology (PSCST) revealed that 300 small scale steel re-rolling mills in the state are being operated at poor thermal efficiency of 20 to 30 per cent resulting in the wastage of heat energy.

A study conducted by PSCST executive director Neelima Jerath comes out with the aforesaid findings. The study revealed that the re-rolling mills contribute considerably towards air pollution, especially in Mandi Gobindgarh and Khanna area.

As such, the PSCST also decided to take up research and development studies for pollution control in this sector. The council has observed that about 40 lakh tonnes of steel is being rolled per annum in about 300 re-rolling mills.

These mills then consume 2.50 lakh tonnes of coal worth Rs 341 crore per annum. Combustion flue gases are generated from the combustion of pulverised coal in these rolling mills which are emitted at as high temperatures as 400 to 650°C along with high concentration of suspended ash particles.

These mills emit 12 tonnes a day of fine particulate matter (3600 tonnes per annum) and 6.7 lakh tonnes of CO2 per annum. Besides, it has been observed that though the pollution problem had been solved to a great extent, black smoke in the morning still persisted. The declaration of Mandi Gobindgarh as a critically polluted area was a matter of concern to the government and public.

However, detailed analysis of the project cycle was taken up and it was found that the answer was available in simple solutions like proper raw material feeding, fuel firing and furnace operating practices.

Dr Neelima Jerath, however, said to understand and address the concern of the industry, the council had been in constant touch with the All-India Steel Re-Rollers Association and the Punjab Pollution Control Board.

She said to tackle the problem of wastage of heat in exhaust flue gases; a shell and shell type waste heat recovery system had been demonstrated for pulverised coal fired mills first time in the country.

“In the skill development programmes, formal off-site and on-site training programmes for 164 mills have been conducted. This has not only led to decrease in visible smoke in ambient air but the industry stands benefited due to reduction in scale loss and fuel consumption. Recognising the expertise of the council in this area, the United Nations Development Programme has also awarded a project for implementing these energy conservation measures (ECMs) in 65 units in Mandi Gobindgarh”, Dr Jerath said.