Influence of coal properties on particulate emission control in thermal power plants in India

Abstract

Rapid industrial growth, consequent to the globalization and liberalization in India, has raised India's thermal power plant capacity to 78343 MW as on March 2003, as compared to 17327 MW during 1980. This is expected to increase to 114920 MW by 2012. The quality of coal, on the other hand, has deteriorated to the extent of 40 to 45% ash in coal, resulting in enormous generation of ash. Since electrostatic precipitators are simple in operation & maintenance and have wider acceptance among the users and consultants in India, precipitators play a vital role in combating particulate emission in power plants. The electrostatic precipitators in India are required to handle large volumes of gas, higher dust concentration, abrasive type of ash and low sulfur & low sodium ash. The magnitude of input parameters seen by the precipitators is peculiar in India. The size of precipitators is also larger, as compared to that in other countries for the same plant rating. In pursuit of protecting the environment against pollution, today, ESPs are designed based on 'emission limit' concept, rather than the earlier collection efficiency basis. The emission from contemporary ESP designs is as low as 20 - 25 mg/Nm{sup 3}. This paper endeavors to address the following topics relating to precipitator design for Indian conditions: emission regulations in India for thermal power plants; Indian coal vs coal in other parts of world; The constituents of coal and ash which has got influence on the precipitation; Comparison of ESP design - current vs over the period earlier; Augmentation/Upgradation of existing older ESP to overcome deterioration of coal quality; Alternate routes to contain the particulate emission (clean coal technology, FGC etc.). 7 refs., 3 figs., 8 tabs.