Method and device for purifying calcium carbide furnace tail gas by using negative pressure dry process

Abstract

The invention discloses a method and a device for removing dust from calcium carbide furnace tail gas by using a negative pressure dry process, which belong to the field of the dust extraction of the calcium carbide furnace tail gas. The method of the invention comprises the following steps of: cooling the calcium carbide furnace tail gas by two stages; introducing the cooled gas into a cloth bag filter and filtering the cooled gas to ensure that the dust content is less than 50 mg / Nm<3> after the filtration; and delivering clean CO2 gas into a waste heat boiler by using a main draft fan and a booster fan, wherein a dust-removal system adopts self-control decompression and is explosion-proof. The device for removing the dust from the calcium carbide furnace tail gas by using the dry process of the invention comprises the following components: an air inlet tube, a decompression and anti-explosion device, an oxygen content alarm, a water cooling sleeve cooling system, a cyclone dust collector, a primary cooler, a settling tank, a secondary cooler, a settling tank, a thermometer, a low-pressure nitrogen protection system, a waste nitrogen processor, a bag-type dust filter, a closed and embedded scraper conveyor and the like. The method and the device have the advantages of simple process, convenient operation, simple equipment structure, safety, reliability, obvious treatment effect and low operation cost, and solve the problems of dust-removal system stoppage caused by the blockage of the traditional pipelines, cooling systems and filter bags.

Description

technical field [0001] The invention belongs to the field of dust removal for calcium carbide furnace tail gas, in particular to a method for purifying calcium carbide furnace tail gas dust by negative pressure dry method. Background technique [0002] The calcium carbide industry was born at the end of the 19th century and is an important basic raw material for the organic synthesis industry. Before the 1970s, ethylene, neoprene, calcium cyanamide, acetic acid, trichlorethylene, and steel desulfurizers could be produced from calcium carbide, and acetylene produced from calcium carbide was widely used in metal welding and cutting. Due to high energy consumption and heavy pollution, it has been gradually replaced by petroleum and natural gas chemicals, and most foreign countries no longer produce them. A few countries that use the calcium carbide method to produce PVC and other acetylene chemical products, according to the technical requirements and energy consumption of calc...

AI Technical Summary

Problems solved by technology

(1) Wet purification technology furnace gas after rough cleaning and fine cleaning, the dust content is reduced to 20mg / Nm 3 Within, the core of its technology is the fine gas scrubber, which adopts the rotor and spindle of multi-layer gear bars. The pipeline of the whole system is easy to be fouled and blocked, and it needs to be cleaned regularly in turn. The physical sensible heat of 10% of the total energy cannot be recovered. The purification process The generated cyanide-containing sewage forms secondary pollution, which is difficult to meet the discharge standards, and the equipment is severely corroded. The entire operating system is expensive, with high energy and water consumption, high operating resistance, and high maintenance costs.

(2) Ceramic filter dry purification technology, the gas dust content is 150g / Nm 3 Reduced to 5~10mg / Nm 3 , the purified gas passes through a tar remover and a heat-resistant steel heat exchanger, the temperature drops from 250°C to below 25°C, and is sent to production after being pressurized by a blower. The key to this technology is the heat-resistant porous ceramic filter element, so The high concentration of dust and tar in the exhaust gas leads to the failure of the heating surface of the heat exchange device due to the adhesion of dust, making the bag filter bag burnt and unusable. The equipment and operating costs are quite high, and ultimately it is impossible to supply clean gas to the gas fired kiln.

Therefore, neither of these techniques is currently used

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