Cement rotary kiln for incineration of hazardous waste

Hazardous waste has chemical reactivity, toxicity, explosiveness and corrosiveness. With the development of industry, a large number of hazardous wastes have been produced. In addition, many environmental pollution problems have been caused due to the unreasonable disposal of hazardous wastes.
Incineration way is one of the most effective ways to reduce, detoxify and recycle hazardous wastes in many treatments. Incineration and disposal of hazardous wastes are two ways, one is to set up a special incineration plant, this method to deal with many types of hazardous waste, but incineration equipment designed to be very high, and is facing such as siting, operating investment and how to deal with the second pollution and other issues; the other is based on the transformation of existing technology on the basis of the transformation of hazardous waste incineration, such as the cement kiln industry, it not only has to meet the technical conditions for the disposal of hazardous waste, and low operating costs, no secondary pollution problems, so the usage of cement rotary kiln burning of hazardous wastes by more and more technical workers attention.
Although the operating temperatures of many industrial kilns can destroy hazardous wastes, rotary kilns have the potential to deal with hazardous wastes. In cement kilns, toxic and hazardous substances can provide some of the heat required for cement production after burning, which can not only solve the waste pollution, but also reduce the burning costs and production costs and many other advantages.
1. A large number of cement rotary kiln disposal of waste
 Cement rotary kilns can dispose of large amounts of waste because the cement industry itself is an industry that consumes a lot of energy. Consumption of fuel, limestone and clay is huge. Generally, 1.6 tons of raw materials are required to produce 1 ton of cement, while 1 ton of coal can produce 6.2 tons of cement. A dry process line with a daily output of 2,000 tons of clinker consumes nearly one million tons of raw materials and fuels each year. According to the preliminary assessment of the Guidelines for the Review of Operation License of Hazardous Waste Colocation in Cement Kilns, the production line can consume tens of thousands of tons of hazardous wastes.
2. The operation characteristics of cement rotary kiln suitable for incineration of hazardous waste
Cement rotary kiln handling hazardous waste and specialized incineration compared to other methods, the characteristics of the cement kiln has many advantages:
(1) High processing temperature
Cement rotary kiln material temperature at 1450 ℃ -1550 ℃, while the gas temperature is as high as 1700 ℃ -1800 ℃. At high temperature, toxic and harmful waste components completely decomposed, the general rate of 99.99% removal of incineration. The incinerator flue gas and material temperature can only reach 850 ℃ -1100 ℃.
(2)Long stay
Cement rotary kiln cylinder length, waste in the kiln at high temperature for a long time. According to the general statistics, the total residence time of the material from kiln tail to kiln head is about 35min, the residence time of gas above 950 ℃ is above 8s, and the residence time above 1300 ℃ is more than 3s, which is more conducive to the combustion of waste and decomposition. The incinerator flue gas temperature is higher than 1100 ℃ only 2s.

(3) Incineration easy to stabilize
Cement rotary kiln is a large thermal inertia, very stable combustion system. It is composed of rotary kiln metal cylinder, refractory bricks built in the kiln, crust formed in the sintering belt and material to be calcined, of great quality, and the refractory material has the heat insulating property, not because of the amount and nature of waste input changes caused by large temperature fluctuations, the system easy to stabilize and control.
(4) Alkaline atmosphere
Production of raw materials used in cement determines the rotary kiln is a basic atmosphere, which can effectively inhibit the discharge of acidic substances, making SO2 and Cl and other chemical compounds to stabilize salts, reducing or avoiding the general combustion of dioxins The phenomenon.
(5) No waste discharge
In the production of cement industry, only the raw materials and clinker produced by the calcination process, there is no incineration of the general incineration furnace slag and other issues; and rotary kiln negative pressure operation of the state, flue gas and dust rarely spill.