This Blog is prepared to understand the operation of Waste Heat Recovery System. We will complete full information about Waste Heat recovery Boiler (WHRB ) in various Parts. In this part we are taking Introduction of the heat recovery system (AQC Boiler) including Principal of working (a) Selection of Waste Heat Recovery System (b Advantages & benefits of Heat Recovery System
PART – I:
Introduction of the WHRB / AQC / Waste Heat Recovery Boiler
PRINCIPLE OF WORKING:
Majority of Cement Industries have rotary Klin and clinkers which are operated around 1000 to 1200 Deg. C. The outgoing gases from these equipment’s are use to heat incoming feed material and the gases get subsequently cooled using Preheater cyclone assembly.
This hot gases coming from the cyclones then pass through ESP or bag filters before letting out to the atmosphere. Subsequent to the heating of the feed material there is lot of balance heat in the gases which can be used for some useful & economic purpose.
However due to major constraints of high cement dust laden nature of these gases it is difficult to do the waste heat recovery in the cement industry. Optimum Utilization of this heat source in existing Equipment’s was a challenge, in this era of “self reliance” and was essential when our import bill of petroleum products is scaling to new heights. It is not only in individual company’s interest, but also in nation interest, that, by recovering the waste heat we reduce our fuel import bill.
In determination for making heat recovery projects successful in Cement Industry, extensive study was carried out so as to make this unique project successful. Following steps are pioneers in this project.
(A.) Selection of Waste Heat Recovery System:
Number of commonly available Heat Recovery Systems for typical Industrial application were available however the nature of the gases been highly dust laden required some unique type of Heat Recovery System.
In view of the high dust laden & the nature of the gas and the space constraints vertical water tube Co-Flow Boiler design was the best suiting design for this application.
In this type of Heat Recovery Boiler the water flows inside the tubes and the flue gas over the tubes. The arrangements of the tubes are made in such a way that the flue gases travel along the length of the tubes. Hence assist the dislodging of the dust particles.
In addition mechanical knocking is done to dislodge the dust and the separation is done in the bottom hopper. Maximum Heat Recovery was done by incorporating an Economiser & Water Pre heater in the system to give optimum steam generation.
(B.) Advantages / Benefits of the Heat Recovery System :
- Reduction in the fuel cost equivalent to the Recovery from the Waste Heat Gases.
- Reduction in pollution of CO2 gases due to the reduction in the fuel consumption as result of which there is a reduction in the flue gas produced.
- Separation of dust & reduction in the auxiliary energy consumption are additional benefits which would be practically observed.
The Waste Heat Recovery in Cement plant is a cost effective way of reducing CO2 emissions which has great opportunities for emission reduction particularly in the developing country like India where this can be met at lower cost than developed countries.
This is a prime candidate technology for Carbon emission reduction projects. This technology as dual benefits of lowering fuel cost and reducing emissions. The project is designed to give a reliable operation predictable savings, preventing global warming & reduction in emission of CO2 gases for the life time.