System and method for improving the comprehensive utilization rate of calcium carbide furnace exhaust gas

Abstract

The invention discloses a system and a method for increasing comprehensive utilization ratio of tail gas of a calcium carbide furnace, and relates to the field of recycling of tail gas of calcium carbide furnaces. The system comprises tail gas purifying equipment, tail gas combustion equipment, steam utilization equipment, an ash collecting device and waste liquid recycling equipment, wherein the tail gas purifying equipment is connected with the tail gas combustion equipment and the steam utilization equipment; the tail gas combustion equipment is connected with the steam utilization equipment and the waste liquid recycling equipment; the tail gas purifying equipment comprises a tail gas afterheat recycling device, a dust removal device and a decoking device; the tail gas combustion equipment comprises a combustor, a boiler, a smoke afterheat recycling device, an induced draft fan and a chimney; the tail gas afterheat recycling device, the dust removal device, the decoking device, the combustor, the boiler, the smoke afterheat recycling device, the induced draft fan and the chimney are sequentially connected to one another; and a plurality of heat storage bricks which are made of rare earth are arranged in the boiler, and are stacked in a cellular manner. The system is environment-friendly; the economic value of the tail gas of the calcium carbide furnace can be improved; and the utilization ratio of the tail gas of the calcium carbide furnace can be increased.

Description

technical field [0001] The invention relates to the field of recovery and utilization of calcium carbide furnace tail gas, in particular to a system and method for improving the comprehensive utilization rate of calcium carbide furnace tail gas. Background technique [0002] The existing calcium carbide production method is usually an electrothermal method. Quicklime and carbon-containing raw materials (coke, anthracite or petroleum coke) are put into a calcium carbide furnace, and an electric arc is used to generate high temperature. The production of 1 ton of calcium carbide can produce about 400Nm 3 Calcium carbide furnace exhaust. [0003] The main components of calcium carbide furnace tail gas include flue gas and dust, the flue gas includes 75-82% CO, 5-15% H 2 , 1.5-5% CO 2 , 7.5-8.5% N 2 , O of 0.15 to 0.3 2 and 1.5-2% tar; dust includes 34.07% C, 40.1% MgO, 4.84% Al 2 o 3 , 1.46% Fe 2 o 3 and 10.04% SiO 2 . [0004] At this stage, enterprises usually igni...

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Problems solved by technology

[0006] (1) After the combustion of the exhaust gas of the calcium carbide furnace, a large amount of NO will be produced 2 , SO 2 and SO 3 Acid gas, after acid gas enters the atmosphere and soil, it is easy to pollute the environment

[0007] (2) Use the tail gas of calcium carbide furnace as fuel to dry ore, as the heat source of the polymerization kiln in the phosphate production system, or as the fuel of the hot blast stove to dry the raw material, because the drying raw material and the heat source of the polymerization kiln consume less energy, It only accounts for 30% of the total heat output of calcium carbide furnace tail gas, so most of the calcium carbide furnace tail gas can only be burned and discharged, and the utilization rate of calcium carbide furnace tail gas is low

[0008] (3) Purified calcium carbide furnace tail gas is used as raw material gas for carbon-one chemical industry, such as sodium formate, formic acid, etc., due to the high purification cost of calcium carbide furnace tail gas and technical limitations, currently domestically developed carbon-one The added value of chemical products is low. Therefore, the economic value of using calcium carbide furnace tail gas as a synthetic raw material is low. The production capacity of carbon-one chemical products is seriously overcapacitated, and the products are discontinued or intermittently produced. The utilization rate of calcium carbide furnace tail gas is low.

[0009] (4) Use the tail gas of calcium carbide furnace as boiler fuel to produce low-pressure saturated steam. The heat consumption in the production of calcium carbide is very small, and the consumption of heat energy is basically not considered; it will lead to waste of saturated steam. When saturated steam is used for power generation, the power generation efficiency is low At the same time, saturated steam is easy to cause cavitation of steam turbine blades. Due to the complex composition of calcium carbide furnace exhaust gas, there are more acidic substances in the gas after combustion, which is highly corrosive and easy to corrode the boiler. Therefore, the cost of using calcium carbide furnace exhaust gas to generate electricity is relatively high.

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