The rise and development of sludge incineration来源： 作者: 阅读：118224 网友评论0条 Updated: 2009-09-02 14:22 Source: Author: reading: 118 224 2010 0 comments
Sludge incineration (thermal decomposition) refers to the process of decomposing sludge solids into three parts: gas, tar, and ash in an oxygen-free or low-oxygen atmosphere at high temperatures (500-1000 ¡ã C). The sludge incineration treatment object is mainly decemented cake. The dewatered cake still has a water content of 45% to 86%, a high water content, and a large volume. It can be dried or incinerated. After drying, the moisture content of the sludge can be reduced to 20% to 40%. Incineration, the moisture content can be reduced to 0, and the volume is small, which is convenient for transportation and disposal.
The initial research on sludge incineration was started by Noack in the United States in 1959, Schlesinger, and others in the Pittsburg Energy Center in 1960. Their common feature is the recovery of energy for purpose. Dehydrated sludge (water content of 65% to 85%, and its solid calorific value is 7500 to 15000kJ / kg) has a low calorific value. Therefore, auxiliary fuel must be added during the incineration process, so a process with minimal auxiliary fuel should be designed. The world's first sludge incineration fluidized bed boiler was built in Lynnword Washington, USA in 1962 and is still in operation today. After 1970, starting from basic research carried out by Japanese researchers Hiraoka and others in 1973, Olexsey in the United States in 1974 and Kalinske in 1975 pointed out the superiority of the incineration process. . At the 8th International Conference on Water Pollution Research held in Sydney in October 1976, Majima and others published a multi-stage furnace decomposition application research report. At the Japan-US Sewer Technology Conference held in Tokyo, Japan in April 1977, Kashiwaya presented a report on the results of multi-stage furnace application research at the Chuanxi treatment plant in Osaka Prefecture. The report confirmed the practicality of the multi-stage furnace incineration process. After that, the remaining sludge incineration plant was built in the Chuanxiong treatment plant and many other places, and it has been running well so far.
South Korea is commissioning a new sludge incineration process recently developed by Samsung Construction Company at the Kwangdong-Li wastewater treatment plant in Kyungki Province. Samutprakam in Thailand is building the largest sewage treatment plant in Southeast Asia, and its sludge treatment unit will use an incineration process. Of the urban sewage plants in China, only the Shenzhen Special Zone sewage treatment plant is used for incineration. The industrial sewage sludge incineration has few domestic applications. The Qilu 200,000 t ethylene wastewater treatment plant designed by the Third Design Institute of the Ministry of Chemical Industry has a sludge volume of 2100 kg / h and uses two-stage horizontal gray bricks. Incinerator burns. The activated sludge boiling incinerator designed by Beijing Yanshan Petrochemical General Plant uses powdery sand needles as the heat carrier, and the sludge is sprayed into the furnace with pressure nozzles. The combustion fuel must be mixed with air to cause hot air. However, the furnace has not been able to run continuously. The Hong Kong government has decided to build two incinerators and energy recovery equipment with a daily capacity of 6000 tons. It is expected to be in 2007. Group 1 equipment will be put into use.
Incinerator types include rotary type such as rotary incinerator, multi-stage type such as vertical multi-stage furnace (multi-stage shaft furnace) and fluidized bed type. The fluidized bed incinerator has the following characteristics: ① Because the particles in the fluidized layer are in a fierce motion state, the mass and heat transfer speed between the particles and the gas is fast, and the processing capacity per unit area is very large; ② due to the fluidized bed Inside is completely mixed. Therefore, the solid waste added to the fluidized bed can be dispersed uniformly instantly except for a particularly large block; ③ Because the carrier itself can store a large amount of heat and is in a flowing state, the reaction temperature of the bed is uniform and rarely occurs Local overheating, easy to control the temperature in the bed. Even if a large amount of flammable waste is thrown in at one time, it will not cause rapid cooling or heating; ④ When handling a large amount of volatile substances (such as oily sludge), there is no danger of causing explosion like a multi-stage furnace ⑤ The structure of the fluidized bed is simple, with mechanical transmission parts, fewer failures, and low construction costs; ⑥ The excess air coefficient can be less; ⑦ Especially the fluidized bed incinerator also has its own unique advantages, such as fuel adaptability Wide, easy to achieve the control of harmful gases such as SO2 and NOx, can also obtain higher combustion efficiency, sludge incineration has a variety of uses, and so on. Therefore, fluidized bed incinerators have been better applied, and their types include Dorr-Oliver fluidized bed incinerators, Copeland type fluidized bed incinerators, and swirling fluidized bed. Incinerator, fluidized bed incinerator with drying section, etc.
At present, sludge incineration is the main method of sludge disposal in Japan, Austria, Denmark, France, Switzerland, Germany and other countries. In recent years, sludge incineration technology has gradually become the mainstream of sludge treatment, and is increasingly favored by countries around the world. . This is because the incineration method has outstanding advantages compared with other methods: ① Incineration can reduce the volume of remaining sludge to a minimum, and it can solve the problem of sludge taking up a lot of space in other methods, which is increasingly difficult for land It is very important in terms of resources; ② After the incineration, the water and organic matter in the remaining sludge are decomposed, and only a small amount of inorganic matter remains as incineration ash, so there is little material to be disposed of in the end, and no heavy metal ions exist The problem is that incineration ash can be made into useful products such as building materials, which is a relatively safe way to dispose of sludge. ③ The sludge is processed quickly and does not require long-term storage; ④ The sludge can be incinerated on site without long Distance transportation; ⑤ Energy can be recovered for power generation and heating.
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