Electrolytic aluminum flue gas quantity and contaminant zero-deviation emission system

Abstract

The invention provides an electrolytic aluminum flue gas quantity and contaminant zero-deviation emission system, which comprises an electrolytic aluminum flue gas defluorination and dust-removal unit and combustion equipment, and further comprises a zero-deviation emission flue and a flue gas circulation unit. An inlet of the zero-deviation emission flue is connected with an emission outlet of a purification unit; an outlet of the zero-deviation emission flue is connected with a combustion-supporting gas inlet of the combustion equipment; a circulation port is formed in the zero-deviation emission flue; a flue gas inlet of the flue gas circulation unit is connected with the circulation port; and a flue gas outlet of the flue gas circulation unit is connected into an electrolytic cell, so that part of the flue gas is circulated into the electrolytic cell for replacing part of air, and the rest of flue gas is fed into the combustion equipment so as to be used as combustion-supporting gas. The electrolytic aluminum flue gas quantity and contaminant zero-deviation emission system further comprises a combustion-supporting gas compensating unit and a combustion-supporting gas distributing unit for supplementing or distributing the flue gas fed into the combustion equipment so as to ensure the flue gas to be matched with the combustion-supporting gas quantity. A control unit is additionally arranged, so that the flow quantity of circulation flue gas is matched with the required cooled flue gas quantity, the temperature of the circulation flue gas is reduced to a required cooling temperature value, and the flue gas quantity fed into the combustion equipment is matched with the combustion-supporting gas quantity.

Description

technical field [0001] The invention relates to the technical field of air pollutant control and energy saving and emission reduction, in particular to a system for reducing the amount of flue gas and pollutants from electrolytic aluminum to zero. Background technique [0002] The electrolytic aluminum industry is an important basic raw material industry in my country, and it is also a high-energy-consuming and high-pollution industry. In 2014, my country’s electrolytic aluminum output reached 23.68 million tons, accounting for more than 40% of the global total output, and also discharged as much as 2.93 trillion cubic meters meters of polluted fumes. Electrolytic aluminum flue gas mainly contains dust, fluoride, SO 2 and CO and other pollutants are 30mg / m 3 , 3mg / m 3 , 200mg / m 3 and 0.1%, the smoke temperature is generally above 100°C, the oxygen content is above 20%, and the emission concentration can basically reach the corresponding national emission standard limit. ...

AI Technical Summary

Problems solved by technology

In terms of sulfur dioxide control, due to the large amount of flue gas produced per unit of electrolytic aluminum, the investment and operation cost of desulfurization facilities using the existing limestone-gypsum method, ammonia desulfurization and other technologies is very high. Therefore, the current electrolytic aluminum industry mainly uses high-cost Low-sulfur anodes control sulfur dioxide emissions, and there is no sulfur dioxide control in flue gas

[0004] Although the current control technology level of electrolytic aluminum plants in my country can achieve the discharge of electrolytic aluminum flue gas up to the standard based on the concentration of pollutants, the huge amount of electrolytic aluminum flue gas emissions makes the total amount of local pollutant emissions remain high, causing serious damage to the surrounding environment. How to further control the discharge of electrolytic aluminum pollutants is an urgent problem to be solved in my country's electrolytic aluminum industry; at the same time, the temperature of electrolytic aluminum flue gas is above 100 ℃, the oxygen content is above 20%, and the CO concentration is about 0.1%. Using the above-mentioned components in the flue gas to recover heat energy is also an urgent problem to be solved for the energy saving of electrolytic aluminum flue gas and the reuse of waste gas.

[0005] At present, there are reports in the literature that electrolytic aluminum flue gas replaces power plant boiler air as combustion-supporting gas, and the gradient utilization of flue gas can be realized. However, no specific feasible plan for electrolytic aluminum flue gas replacing combustion-supporting gas has been given.

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