Flue gas desulfurization and denitrification technology plays a key role in industrial emission reduction, but it also faces many technical difficulties in actual application. These difficulties not only affect the treatment efficiency and equipment life, but are also directly related to the operating cost and the stability of standard emissions. The following analyzes the main technical difficulties of flue gas desulfurization and denitrification from the aspects of process, equipment, operation management, etc.:
1. The flue gas composition is complex and changeable, and the adaptability requirements are high
The composition of flue gas is affected by various factors such as fuel type, combustion conditions, industrial processes, etc., resulting in large fluctuations in the concentration of pollutants such as SO₂, NOₓ, dust, and heavy metals. Some flue gases also contain corrosive gases (such as HCl, HF) or side reaction products (such as NH₄HSO₄), which will interfere with the desulfurization and denitrification system. How to choose a technical solution with good adaptability to different flue gas components is an important problem in the early stage of design.
2. Limited desulfurization and denitrification reaction conditions
Different technical routes have different requirements for reaction temperature, gas velocity, concentration, humidity and other conditions. For example, the SCR denitrification system needs to be between 300℃ and 400℃ to maintain a high efficiency, while the desulfurization device mostly works below 150℃. If the two are used in series, it is necessary to adopt flue gas heat exchange and other methods to cool down or divert, which increases the complexity and energy consumption of the system. In addition, temperature fluctuations may lead to problems such as catalyst deactivation and reduced reaction efficiency.
3. Catalyst and absorbent failure and by-product problems
SCR denitrification relies on catalysts to maintain reaction activity, but catalysts are easily ineffective due to poisoning (such as the influence of sulfur, arsenic, and dust deposition), and need to be replaced regularly, which is costly. Improper use of limestone slurry in wet flue gas desulfurization will cause scaling, block the nozzle, and reduce the absorption efficiency; the reaction residue in dry or semi-dry method is not easy to handle, and the absorbent utilization rate is low, resulting in increased operating costs and by-product accumulation problems.
4. Severe system corrosion and wear
The flue gas contains moisture and acidic gases, which are very easy to form corrosive media during condensation or wet reaction, causing serious corrosion to the inner wall, pipelines, fans and other components of the equipment, shortening the service life of the equipment. At the same time, the flue gas carries a large amount of dust particles, which causes continuous wear on components such as circulating pumps, fan impellers, and nozzles, increasing maintenance frequency and spare parts consumption.
5. High requirements for system operation stability and automation level
The desulfurization and denitrification system involves multiple links such as fluid transportation, chemical reaction, material transportation, and temperature control. The stability of the system operation depends on a complex automatic control system. If the control system does not respond in time or the data is inaccurate, the reaction conditions may deviate from the optimal state, and even ammonia escape, slurry overflow, and excessive emissions may occur. Therefore, high requirements are placed on the integrated commissioning and maintenance of automation systems such as DCS and PLC.
6. Difficulty in technical integration and coordination
In actual projects, flue gas desulfurization and denitrification often work in conjunction with dust removal, waste heat utilization, wastewater and waste residue treatment, and other systems. There is energy exchange, logistics interface, and operation coordination between the systems. How to scientifically plan the process flow, optimize the layout, and coordinate operation is a major technical challenge to maximize overall efficiency.
In summary, the main technical difficulties of flue gas desulfurization and denitrification are concentrated in system adaptability, reaction condition control, core material stability, equipment corrosion resistance and wear resistance, and intelligent operation. To solve these difficulties, enterprises need to continuously optimize equipment selection, operation management, technology upgrades and intelligent transformation to ensure the long-term, safe and efficient operation of the pollution control system.