A dust removing-denitration integrated device and method for medium- and low-temperature flue gas

Abstract

The invention relates to a dust removing-denitration integrated device and method for medium- and low-temperature flue gas. The device includes a dust removing purification unit, an ammonia-air mixingand injecting unit, a heat exchange unit and a denitration unit which are arranged in a column body in order from bottom to top. The lower part of the column body of the dust removing purification unit is provided with a plurality of air inlets along the circumferential direction. Each air inlet is connected to one end of a flue gas feeding pipe through an air feeding branch pipe. The other end of the flue gas feeding pipe is connected to a desulfurated flue gas outlet of an outer desulfuration unit. Air inflow evenly-distributing guide plates and filter bags are disposed in the column body of the dust removing purification unit. A plurality of rows of the filter bags are evenly and vertically distributed in the column body. The air inflow evenly-distributing guide plates are disposed between the air inlets and the filter bags. Pulse-jetting apparatuses are arranged above the filter bags, and are connected to an outer compressed air conveying pipe. The device and the method integratedust removing, heat exchange and denitration, and are high in dust and NOx removing efficiencies. The device is simple in structure, reliable to operate, low in investment and operation cost, and longin service lifetime.

Description

Technical field [0001] The invention relates to the technical field of coke oven flue gas purification, in particular to an integrated device and method for medium and low temperature flue gas dust removal and denitration. Background technique [0002] At present, the country has increasingly higher requirements for environmental protection. The "Emission Standard of Pollutants for the Coking Chemical Industry" (GB16171-2012) restricts the emission of dust and NOx from coke oven flue gas, and it is strictly forbidden to discharge the flue gas without treatment. At this stage, the treatment technologies of coke oven flue exhaust gas dust and NOx mainly include wet dust removal and denitration technology, activated carbon dust removal and denitration technology, and integrated technology of medium and low temperature flue gas dust removal and denitration and denitration catalyst thermal analysis, but these technologies are in actual operation. There are some drawbacks. [0003] The ...

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Problems solved by technology

[0005] The Chinese patent with the patent number ZL201410478420.0 discloses a "medium-low temperature flue gas desulfurization, dust removal, denitrification and denitrification catalyst thermal analysis integrated device", which includes a desulfurization, dust collection and purification section integrated in a tower body from bottom to top, analysis and ammonia injection In the mixing section and the denitrification reaction section, first filter the incompletely reacted desulfurization agent and desulfurization ash in the flue gas through the filter bag, so that the flue gas can fully contact with the desulfurization agent when passing through the filter dust layer for further desulfurization, and then spray the ammonia gas into the filter bag The filtered flue gas is fully mixed with it, and then discharged into the atmosphere after being denitrated by the denitrification catalyst; at the same time, a high-temperature thermal analysis device is installed to perform online thermal analysis regeneration of the denitrification catalyst to maintain the continuous service life of the medium and low temperature denitrification catalyst; The flow structure is set so that the flue gas velocity field and temperature field are evenly distributed in the integrated device of medium and low temperature flue gas desulfurization, dust removal, denitrification and denitrification catalyst thermal analysis to achieve the purpose of efficient denitrification; However, in the actual operation of the project, it was discovered that the hot blast stove has little effect on the thermal analysis of the catalyst, and is more used for heating flue gas, and will lead to the following situations: 1) The investment cost of the hot blast stove is high, increasing the investment and operation of the project Cost; 2) The hot blast stove will increase the flue gas volume by mixing high-temperature flue gas to increase the temperature of the flue gas, which will increase the investment and operation cost of the project; 3) The hot blast stove needs to be chained with the entire system to increase the complexity of the entire system ; 4) Poor control of the hot blast stove is prone to new NOx generation, increasing the operating load of the equipment

In addition, the price of the catalyst selected to adapt to the characteristics of medium and low temperature flue gas is much higher than that of ordinary catalysts on the market, resulting in a large increase in engineering costs

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