Refurbishment Modernisation – Technology or Case Study: Electro Static Precipitator (ESP)

摘要

Coal will remain one of the most important sources of power generation in India. With increased public awareness, and by the initiative of the Indian government toward cleaner energy, the emission standards for power plants have become more and more stringent. In INDIA, considering the chemical composition of the fuel (Coal), operating parameters of the power plant, Electrostatic Precipitator (ESP) is still the preferred technology when it comes to particulate emission control. Thanks to the recent developments in ESP technology in terms of type of discharge electrodes, High voltage TR, and controllers. Hamon Research Cottrell (HRC) have done significant contribution in this field for the last 100 years both in green field as well as in renovation & modernisation. The revised guidelines for particulate emission is a challenge for existing/old plants and the solution is to be tailor made specific to the plant. Two predominant questions needs to be answered to arrive at an optimum solution. - Is the ESP performing to its designed condition? This is vital because even the ESP’s installed 10 – 15 years before was designed for an outlet emission of 50mg/nm3. - Is there space available in the layout for adding additional ESP fields? Either in series or parallel. The ESP’s installed in Indian power plants are significantly oversized, compared to other countries. ESP for a 660 MW coal fired Power plant in India will have 54 to 64 fields, as against 16 field elsewhere in the world , still many ESP’s in Indian power plant are not performing to its design condition. In HRC, our engineers would always go into the basics before suggesting a major upgradation which calls for significant investment in terms of time & money. Our suggestions include – a) Working of Hopper level switches, we have seen practical cases where the hopper level switch bypass has caused ash built up to 70% of the casing. Though the ash is evacuated, the Discharge electrode had undergone a permanent deformation. b) Computational flow dynamics CFD): Minimise dust entrainment, maximise the utilisation of the available collection surface area. This paper, presents the case studies about HRC recent experience in R & M of a 2 x 600 MW ESP at a coal fired power plant at Vietnam.