Production system of suspended-state calcined coal gangues

Abstract

The invention discloses a production system of suspended-state calcined coal gangues. The production system comprises a material preparing and feeding sub system, a preheating and decomposition furnace-calcining sub system, a product cooling and heat-recycling sub system, a hot air preparing and supplying sub system and a system power and waste gas-purifying sub system, wherein the material preparing and feeding sub system is used for quantitatively and stably supplying coal gangue powder to a pre-heater; the preheating and decomposition furnace-calcining sub system is used for preheating materials to a set temperature under a suspended state, and decomposing and sintering the materials in a decomposition furnace; the product cooling and heat recycling sub system is used for sucking in cold air to cool the sintered materials under the suspended state to obtain low-temperature activated coal gangues; the hot air preparing and supplying sub system is used for ventilating hot air to the hot air furnace for burning pulverized coal or fluidized block coal, and providing hot air to the decomposition furnace of the preheating and decomposition furnace-calcining sub system, wherein the hot air is from the product cooling and heat-recycling sub system; and the system power and waste gas purifying sub system is used for providing gas flow power to the preheating and decomposition furnace-calcining sub system, purifying all waste gas of the preheating and decomposition furnace-calcining sub system and excessive gas emitted by the hot air preparing and supplying sub system. The production system disclosed by the invention can massively, efficiently, continuously and stably produce and process high-activity cinerite coal gangues.

Description

technical field [0001] The invention belongs to the production field of calcined activated coal gangue, in particular to a production system of suspended calcined coal gangue. Background technique [0002] Coal gangue is solid waste discharged during coal mining and coal washing. In 2012, China's raw coal output reached 3.65 billion tons, and coal gangue production was about 680 million tons (National Bureau of Statistics of the People's Republic of China. Statistical Bulletin of the People's Republic of China on National Economic and Social Development in 2012 [EB / OL].[2013-02-22 ].http: / / news.xinhuanet.com / politics / 2013-02 / 23 / c_114772758.htm), the comprehensive utilization rate of coal gangue in 2012 was only 62.2% (National Development and Reform Commission of the People’s Republic of China. China Comprehensive Utilization of Resources Annual Report (2012)[EB / OL].[2013-04-09].http: / / district.ce.cn / zt / zlk / bg / 201304 / 09 / t20130409_24275052_3.shtml). The existing coal gangue...

AI Technical Summary

Problems solved by technology

Because the large-grained materials are piled up, and the thermal conductivity of the gangue material is low, not only the heat exchange area between the material and the hot air flow is small, and the heat exchange efficiency is low, but also the temperature difference between the inside and outside of the gangue block is large, and the external temperature of the block is too high. Burning, internal under-burning, seriously affect product quality

[0005] Suspension calcination is to use powdery coal gangue material (generally 80μm sieve is 10%) to disperse in the suspension hot air flow, "precalcining kiln bypass ventilation and coal gangue dehydration process" patent [patent number CN1718556], cooked with cement The high-temperature flue gas produced by the preheating and pre-decomposition kiln bypass air is used as the heat source, and the powdered coal gangue is heated in the flue gas pipe for calcination and activation. This technology makes full use of the heat source of the waste gas discharged from the cement clinker kiln, and has low operating costs. The single-calcination coal gangue has the advantages of large output, but this production process has the following inherent defects: (1) Bypass ventilation is only a specific measure taken to reduce the content of sulfur, alkali, and chlorine in the kiln, and this step will not be carried out when the kiln system is normal. operation, the coal gangue calcination system does not have a stable supply of heat source, and cannot guarantee the continuous production of calcined coal gangue

(2) In the calcination process facilities, the materials at room temperature are directly put into the hot flue gas at 900°C for direct calcination, without multi-stage preheating and separation device, the temperature of the waste flue gas discharged after calcining coal gangue is high, and the thermal efficiency of the system is low.

(3) The production and operation process requires flue gas at 900°C, and the temperature of the flue gas released by the bypass is generally 1250°C, which is not conducive to the utilization of flue gas heat when mixed with cold air to cool down

The production process has the following defects: (1) The working heat source system is unreasonable

Although the high-temperature flue gas from the cement kiln system can be continuously extracted as a heat source to ensure the continuity of calcined coal gangue production, the extraction of hot flue gas from the calcination system destroys the process balance between the cement kiln and the preheating and pre-decomposition system, disturbing the cement calcination system process operation

The pulverized coal is injected into the bottom of the calciner for combustion as a supplementary heat source. The high-temperature exhaust gas from the preheating and pre-decomposition system has insufficient oxygen content, which is not conducive to the full combustion of pulverized coal. Moreover, the combustion of pulverized coal at the bottom of the calciner is easy to form slag, which affects the normal operation of the system.

(2) The preheating system is unreasonable

After the preheating gas temperature of the first-stage cyclone is reduced by 150-200°C, the temperature of the flue gas discharged from the decomposition furnace in normal operation is about 850°C. After the separation cyclone is cooled by 50°C, only the heat exchange between the first-stage cyclone and the material is exhausted. The exhaust gas temperature is 600-650°C, and the heat utilization rate of the system is low

(3) The operability of the cooling system is poor, and the heat recovery efficiency of the airflow is low

To sum up, the technical scheme of calcination and activation of coal gangue in a suspended state has a large heat exchange area between the material and the airflow, and high heat exchange efficiency, but there is no feasible production process system

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