Method for heating flue gas entering denitration system by utilizing heat of conversion section

Abstract

The invention discloses a method for heating denitration flue gas by utilizing heat of a conversion system. A denitration device is arranged behind a secondary absorption tower, and a tail gas heat exchanger is additionally arranged in an original conversion system. Flue gas at a shell pass inlet of the tail gas heat exchanger is tail gas absorbed by the secondary absorption tower; the flue gas atthe tube pass inlet of the tail gas heat exchanger is flue gas converted from the tube pass outlet of a third heat exchanger; the flue gas at the tube pass outlet enters a first absorption tower to be absorbed; the temperature of the flue gas at the shell pass outlet after heat exchange is 130-150 DEG C, the pressure is 3-7KPa, and the flue gas condition meets the requirement of being introducedinto a denitration reaction system. After flue gas enters a denitration system to be treated, the content of NOX in tail gas can be controlled to be smaller than or equal to 50 mg / m<3>. According to the invention, nitrogen oxides in the tail gas can reach the national emission standard, and the heat of the tail gas can be utilized, so that the investment of supplementing a heat source and equipment from the outside of the system is greatly reduced, and the system has very good practicability and obvious economic benefits. And the added process and principle are simple and clear, the pipeline is clear, and the operability is very strong.

Description

technical field [0001] The invention belongs to the technical field of chemical engineering and environmental protection, and relates to a method for heating flue gas entering a denitrification system by using heat from a conversion section. Background technique [0002] Various types of acid production facilities in my country, such as those involving alkylation waste acid pyrolysis regeneration flue gas acid production, flue gas acid production, sulfur acid production and other processes, will produce a large amount of gas due to the high temperature oxidation and combustion reactions of cracking furnaces and incinerators. Nitrogen oxides are now beginning to pay attention to the treatment of such nitrogen oxides, and continue to carry out denitrification treatment on this basis. However, how to set up the denitrification device and which stage of the acid system is more suitable for treatment are still in the exploration stage. [0003] At present, some are installed on t...

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Problems solved by technology

However, how to set up the denitrification device and which stage of the acid system is more suitable for treatment are still in the stage of exploration

[0003] At present, some are installed on the flue gas pipeline from the purification section to the dry suction section, which will inevitably lead to some SO 2 and SO 3 Loss, that is, the reduction of acid production, may also have a poisonous effect on the denitrification catalyst. Some are installed on the pipeline before the conversion reaction in the conversion section, which may cause a greater impact on the temperature-sensitive conversion section. and will lose part of the SO 2

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