How to measure heat energy savings?

In recent years, fuel prices have tripled compared to 15 to 20 years ago. Foreign countries have conducted extensive research on energy conservation issues, using modern technology to analyze common structures and operating methods in order to obtain updated designs and operating procedures, and to explore and seek new structures and operating methods.

The West German Salzgitter Company designed and built two large push-type furnaces with the same capacity. Furnace No. 1 was put into operation in 1971, and Furnace No. 2 was put into operation in early 1976. When designing Furnace No. 2, considering the increase in fuel prices, a higher infrastructure investment was made to reduce fuel consumption in production. The design of the T-type was applied to the mathematical model. A new solution was derived for the differentially expressed heat balance and heat exchange equations. Compared with the conventional method, this method can reduce the computer's calculation program and storage capacity. It can also determine the horizontal temperature gradient caused by the rail (black mark on the rail), heat balance data, and the temperature field of the upper wall, furnace gas and slab of the furnace length.

A series of fuel-saving measures were taken in the design of Furnace No. 2. Such as: 1) air preheating to above 6000℃ to improve waste heat recovery rate (air preheating of furnace No. 1 is 4300℃); 2) the wall (especially the furnace top) is well insulated; 3) alloy steel guide baffle burners are used to achieve radiation furnace top micro-firing to improve heat transfer efficiency.

The trial production data of furnace No. 2 is completely consistent with the numerical model prediction data. The final temperature was measured to be 12500℃ by a thermocouple inserted into the slab borehole, the temperature difference between the upper and lower surfaces was less than 200℃, and the horizontal temperature difference was not more than 500℃. The fuel consumption of furnace No. 2 is 19% less than that of furnace No. 1, and the heat consumption is saved by 81.5 kcal per kilogram of steel. When the annual output of the two furnaces is 1.543 million tons, furnace No. 2 can save 114,100 million kcal of heat per year. According to the current European fuel price of US$8/million kcal, the fuel cost can be saved by 913,000 yuan per year. The construction cost of the No. 2 furnace was approximately $1.5 million more than that of the No. 1 furnace.