Shandong Shanghai Wo Fung Fung Group Cement Co., Ltd. has a 5000t / d new dry process clinker production lines, instead of supporting 9MW waste heat power generation on May 15, 2009 a power grid success.


1 problem
     Cogeneration kiln bypass operation is fully closed, the cyclone boiler outlet temperature of the kiln is below 250 ℃, finished excessive moisture coal mill system (requires moisture ≤2.0%), clinker crusher at a positive pressure to take gray serious. Kiln bypass had to open 10% to 15%, although the clinker crusher at a negative pressure and the cyclone outlet steam temperature, but heat boiler to reduce the amount of the kiln, the total amount of waste heat power generation fell more. Figure 1 is a transformation of the former kiln heat retrieval systems.

Before the transformation

1-To Cyclone separator Hot air valves(3550mm),2-Kiln head boiler,3-Out Cyclone separator Hot air valve(1500mm),4-Hot air valve(1500mm),5-Cold air valve(800mm),6-Cold air valve(800mm),7-Hot blast stove outlet manual valve,8-Coal mill,9-The coal mill dust collector,10-The electric dust collector at kiln head,11-Cyclone separator,12-Hot blast stove,13-The coal mill fan,14-Kiln head exhaust fan,15-grate cooler,16-Rotary kiln,17-Clinker crusher

2 Analysis
     Kiln bypass open 10% to 15%, freeing part of the low-temperature heat and raise the temperature of the hot gas outlet of the cyclone increases clinker crusher at negative values, but the amount of heat into the kiln to reduce boiler more relevant kiln the amount of steam boiler head is not high, only about 50% of the design, resulting in the total power generation is not high, the total power generation in the 4000 ~ 5000kWh / h. The amount of steam boilers kiln at about 12 t / h (design 24 t / h), the amount of steam boiler kiln has been 21 ~ 22t / h (design 23t / h).


3 solutions and results
     Actual production, in order to increase the heat capacity of the boiler into the kiln, but also to ensure the supply of coal mill hot, stable negative value at the crusher. In the bottom of the hot kiln bypass valve pipeline with a diameter of 1000 mm increase in pipe connections and piping hot air into the coal mill, this tube can pull the lower part of the temperature of the hot air from the low-temperature cooler, and then with the higher part of the hot air temperature Sec, Sec reduce coal mill for high-temperature hot air extraction capacity. Increasing the diameter of 1000 mm pipeline, both to ensure the supply of coal mill system of hot air, but also improves the heat capacity of the boiler kiln, but also to ensure that the negative value of the clinker crusher at reducing the risk of gray phenomenon, kiln bypass valve can be fully closed. Figure 2 is a schematic diagram of the kiln after technical innovation pipeline.

      Laboratory timely adjustment according to fluctuations in raw material composition of the ingredients burning program; the continuous optimization of operational control, operation and use of thick material layer under the grate fan base valve fully open; coal mill operation to increase the diameter of 1 000 mm new valve (Figure 2 shown in "A", the other numbers in Figure 1 Note) fully open, two-stage valve opening of the hot air to minimize, the amount of hot air into the kiln increases the boiler and to increase the hot air temperature. After transformation, the amount of steam pipes in the boiler kiln 20t / h or so, the total electricity generation increased to 7000 ~ 8000 kWh / h, generating capacity increased by 120000 kWh 150000 kWh, annual increase

Power: 330 days × (15 000-120 000) = 9.9 million kWh. Technical innovation around the system-related factors in Table 1.

Item	Electric Dust Collector At Kiln Head		Cyclone Separator Outlet		Ateam Turbine Inlet		Power generation
	Temperature(℃)	Negative Pressure(Pa)	Temperature(℃)	Negative Pressure(Pa)	Temperature(℃)	Negative Pressure(Pa)	(kWh)
Before Modi.	99	1100	430	600	347	0.69	4800
After Modi.	123	615	278	240	279	0.71	8000