Calcium carbide furnace purification ash back-to-furnace combustion system

Abstract

A calcium carbide furnace purification ash back -to-furnace combustion system comprises a sealing type purification ash collecting bin, a pneumatic transmitter, a sealing type discharging bin, a conveying air source and a flow mixing chamber. Nitrogen is input into the sealing type purification ash collecting bin and the pneumatic transmitter, and the sealing type purification ash collecting bin and the pneumatic transmitter are made to be communicated with each other. Pneumatic transmission pipes are connected with the sealing type discharging bin and the pneumatic transmitter, and nitrogen is also input into the pneumatic transmission pipes. The conveying air source is a pressure source for terminal conveying, and can directly convey and recycle purification gas of calcium carbide manufacturing devices on site, and solve the problems that purification ash is difficult to recycle and convey due to the characteristics of being high in temperature, easy to burn and explore, and adhesive, and achieve the purpose that on-site conveying is smooth without being blocked. The sealing type discharging bin can ensure that the conveying amount of purification gas fed in a combustion furnace is stable. The transporting expenditure for purification gas recycling can be omitted, the output value is improved, the energy-saving benefits are obtained, and the purpose of emission reduction of pollutants is achieved.

Description

technical field [0001] The invention relates to a recycling system for dusty flue gas, in particular to a combustion system for returning purified ash from a calcium carbide furnace to a furnace. Background technique [0002] The tail gas temperature of the closed calcium carbide furnace is high, the gas volume fluctuates greatly, the composition of the tail gas is complex, the dust particle size in the tail gas is small, the viscosity is strong, the tail gas temperature is 650 to 1200 ℃, and the dust concentration is 100 to 250g / Nm 3 , containing about 75% CO and a small amount of coal tar, so the exhaust gas of the closed calcium carbide furnace is flammable, explosive, and the dust is viscous. At the same time, the dust particles have a large specific area, light specific gravity, and are difficult to dissolve in water. The exhaust gas composition of the closed calcium carbide furnace is shown in Table 1: (by mass) [0003] [0004] It can be seen from the above table...

AI Technical Summary

Problems solved by technology

[0006] (1) Utilization of wet purification, this method cools down the exhaust gas quickly, and the three-stage water washing efficiency is high, but there is tar precipitation, so the wall of the device is easy to stick to tar, and it needs to be cleaned frequently, causing secondary pollution;

[0007] (2) Dust removal after direct use, that is, the tail gas of the sealed calcium carbide furnace is not subjected to dust removal, but is directly used as fuel, because the dust has a strong adsorption force, and it is easy to bond on the heat exchange area of ​​the boiler. In severe cases, the thickness can reach 5 to 10mm, it is difficult to remove completely even if the soot blowing and cleaning technology is used, and the furnace must be shut down to clean the soot, which reduces the operating efficiency;

[0008] (3) Reuse after dry dust removal. This method is divided into two types. One is to pass the exhaust gas of the calcium carbide furnace through the air cooler and enter the sedimentation dust collector, and then enter the lower stage after two-stage dust removal, which greatly reduces the exhaust gas. temperature, but the dust removal effect is not good, and the dust that has not been removed will bring troubles to the lower-level use. It is often necessary to stop the dust removal, which reduces the benefit. In addition, this method passes the tail gas of the calcium carbide furnace into the forced air cooler and then sends it to the Lime kiln, the equipment is simple and easy to operate. Although the main engine needs to choose a high-temperature resistant fan, the cost is relatively high, but the fan runs for a long time, there is no abnormal accident and generally does not accumulate dust, and the dust obtained after purification can be smoothly discharged to the ash unloading unit. However, the bag filter is easy to be burned; the other is that the exhaust gas of the calcium carbide furnace is first sent to the sedimentation dust collector through the rough air fan, and the large particles of dust in the exhaust gas are removed by gravity, and part of the heat is taken away, and then passed through the cyclone cooler , the jacketed cyclone device makes the tail gas rotate into the device, removes the remaining large particles of dust, and takes away most of the heat. If the first stage cyclone cooler fails to completely remove the dust or the temperature drop does not reach the bag filter If the temperature is acceptable, the control system will automatically start the second or even third-stage cyclone cooler to remove dust and cool down until the dust removal is complete and the temperature drop meets the requirements. Finally, the purified tail gas will be sent to the lime kiln. The ash (called purified ash) is conveyed and collected to the ash unloading tank through a chain scraper machine. Due to the high temperature of the purified ash (between 170 and 180°C), it is powdery and easy to stick, flammable and explosive, so it is When going to the lower-level users, it needs to be processed by the corresponding process, and then transported to the lower-level users by using a special transport vehicle

However, in the prior art, the collected purification ash is either treated as ordinary slag, causing the land to be occupied and polluted; or after corresponding treatment, it is transported to the user by a special transport vehicle. Not only is it inconvenient to transport, but it also increases the cost of recycling the purified ash

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