Low-temperature operation prevention automatic protecting method and control system for flue gas denitrification catalyst

Abstract

The invention belongs to the technical field of flue gas denitrification and relates to a low-temperature operation prevention automatic protecting method and control system for a flue gas denitrification catalyst. The low-temperature operation prevention automatic protecting method for the flue gas denitrification catalyst comprises the steps that S1, the critical temperature (please refer to the specification) is preset in a distribution control system (DCS); S2, a temperature sensor detects the flue gas temperature Q in a flue in real time and has an access to the DCS; S3, the DCS counts up the continuous operation time A of the condition of MIT<Q<MOT and the continuous operation time B of the condition of RT<Q<MXOT; and S4, the DCS controls a valve of a denitrification and ammonia supply pipeline and a timer by referring to the continuous operation time A, the continuous operation time B, the flue gas Q and the critical temperature. By means of the control method, control automation can be achieved, the temperature and time are controlled more accurately, and the denitrification catalyst is prevented from being irreversibly damaged by manual control deviation.

Description

technical field [0001] The invention belongs to the technical field of flue gas denitrification, and in particular relates to an automatic protection method and a control system for a flue gas denitrification catalyst against low-temperature operation. Background technique [0002] Nitrogen oxide (NOx) is one of the main air pollutants, which will promote the formation of acid rain, increase the concentration of ozone in the near-surface atmosphere, produce photochemical smog, and affect air visibility; it has a strong stimulating effect on the human body, causing respiratory diseases, serious will result in death. [0003] The main source of nitrogen oxides in industrial production is the combustion of fuel. The combustion of fuel is mainly the combustion of coal. The temperature required for the chemical reaction of SCR denitration process mainly depends on the type of denitration catalyst. When the flue gas temperature is lower than the lower limit of the applicable temp...

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Problems solved by technology

In addition, once the denitration catalyst is poisoned and fails, the cost of active regeneration or replacement of a new denitration catalyst will be extremely expensive, which will also affect the economic benefits of the enterprise

In summary, if the activity of the denitrification catalyst in the flue gas SCR process denitrification system is reduced or even eventually poisoned and fails, it will have adverse effects on the operation, safety and environmental protection of the entire enterprise, especially the environmental protection will have a greater impact on the entire society. In actual operation, ultra-low temperature operation is prone to occur, and the probability of ultra-high temperature operation is relatively small. Therefore, how to protect the denitrification catalyst against low temperature operation is an important research topic in the flue gas SCR process denitrification technology

[0004] In order to protect the activity of the denitrification catalyst and improve the efficiency of flue gas denitrification, the denitrification catalyst is often activated by adjusting the flue gas temperature of the denitrification system. If the flue gas temperature is too high, the structure will change and become inactivated, and the flue gas temperature is too low. , and operating in this low temperature range for too long will cause irreversible damage to the denitrification catalyst. When the denitrification catalyst is operated at a low temperature within a certain range for a short The denitrification catalyst can recover its activity for the necessary time in the regeneration range. Since the change of flue gas temperature may occur at any time, relying on the staff to carry out statistics has the following disadvantages: first, the statistical results may be inaccurate, second, the workload of personnel is large, and third It is because the technical requirements are cumbersome and the statistical method is not reliable, which may cause irreversible damage to the activity of the denitrification catalyst

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