Waste Heat Recovery System for a Glass Industry

Under the financial support from the PCRA (Petroleum Conservation research Association), a demonstration study was undertaken at Firozabad in the Glassware industry. One of the demonstration projects was to develop a Waste heat recovery system from the exhaust gases of 1 MW DG set (Gas based). The project was undertaken at M/s Farooqui Glass Works are located in Firozabad town. The company is engaged in manufacturing of glass ware of many types. M/s Nannumal Glass Works is a sister concern of this company.
To meet the power requirements of both units, M/s Farooqui Glass works have installed a Natural gas based power generation unit of 1,000 Watt (1 MW) capacity.
Parallely, the company has a huge requirement of air for their glass melting furnace.
The existing practice of the company was to use the atmospheric air at ambient temperature as the secondary air for the furnace.
On a careful observation, it was observed that the exhaust air of the power generator was of the order of about 4900C.
A heat exchanger was designed which uses the heat from the exhaust gases of the natural gas based Generator set of 1 MW rating, to pre heat the secondary air, which then is fed to the furnace. While the project formulation and hardware development was already undertaken by the company, the system was not functional as the desired amount of hot air was not being generated.
Appropriate system modifications for raising the differential pressure to assist proper flow of the hot air were worked out and implemented.

The temperatures of the pre heated secondary air could be raised to a level of 190 degree C. This has effected a savings of about 7% of the gas. At the level of about 5000 cubic meters of gas per day, the savings were of the order of about 350 m3 per day or about 1,10,000 m3 per year. This has helped the company in bringing down the expenses by about Rs. 7,00,000 per year. At an investment level of about Rs. 15,00,000 towards the heat exchanger system, the payback period of the investment was about 2 years. This was a very welcome proposition for the management. Supporting photographs are provided in detailed write up below.