Online Monitoring to identify Economizer hopper chocking

Thermal power plant is not the clean technology to be considered in the present times. However, while solar technology is coming up pretty first, the thermal is going to stay may be another 10 to 12 years if not more. If the multi-layer solar PV cell becomes success the death of thermal technology may be faster but till that happens all the smokey and firey thermal power plants will keep on running despite you & I grumble or not. Ash is one of the major problem areas of a typical thermal power plant. So much ash is generated that we really don’t know how to handle such huge quantity of ash! It’s highly erosive, it damages soil, it spoils air yet we have to handle it every moment to sustain the demand of power every day.

To produce 500 MW power, [which can cater to a village of say 20,000 households with 2.5KW consumption each] we have to burn about 300 to 400 tons of coal every hour which produces about 110 to 150 tons of ash every hour !

Now inside a boiler at every turn the ash rubs with the structures, erodes and then settles in hoppers which are then taken away using water blowing or pneumatic conveyor. In case these conveying systems does not work properly, the ash settles at that high temperature up to a very high level which then can burst open the hopper or can collapse the structure due its own weight. Hoppers are designed for collection and subsequent transfer; they cannot hold it and that too at that high temperature. Hoppers can be considered as a guidance system of ash inside boiler to the outside of boiler using air or water as medium. Economizer Hopper chocking is a frequent problem that we have been facing at NTPC. We are now experimenting with an innovative approach by continuous monitoring the skin temperatures of the hopper to identify when chocking occurs. I have shared the details in form of a case study here (This system is now protected by NTPC Patent right).