The waste heat in cement production mainly comes from the calcination kiln, and the temperature in the kiln reaches 1,400°C. The new modern dry process uses the high temperature exhaust gas discharged from the furnace to dry and preheat the decomposition of raw materials, and then recycles the low temperature exhaust gas and the exhaust gas from the head grate cooler of the kiln (cooling cement raw materials) for electricity production. For each ton of raw materials produced, the energy production rate by waste heat recovery can reach 35 to 40 kW.
Cement production is continuous and the flow of hot exhaust gases depends on the scale of the production line. Taking a cement kiln with a daily output of 2,500 tons of raw material as an example, the exhaust gas parameter of the preheater at the end of the kiln is 176,000 m3/h standard, 330°C the temperature of the exhaust gases for drying at the end of it; the oven is at 210°C; the total exhaust gas from the grate cooler at the furnace head is 100,000 m3/h standard, 290℃. Use the AQC at the head of the furnace and the SP boiler at the tail of the furnace to generate high-pressure steam for power generation