Smoke purification - ultra-low emissions and low nitrogen combustion
YCOS Smoke Purification Flow Field Simulation Diagram
Optimization of flow field in SCR reactor
Simulation of Flow Field Distribution of SCR Ammonia Spray Mixed Flow in Hazardous Projects
Solid distribution at the outlet of CFE semi dry absorption tower
Airflow distribution of CFB semi dry absorption tower
Solid Particle Tracer Distribution in CFB Semi dry Absorption Tower
Schematic diagram of YCOS flue gas purification
SNCR denitration Ultra low humidity - dry desulfurization and dust removal Integrated desulfurization and denitrification
Integration of whitening and waste heat recovery
Mercury removal process from flue gas of coal-fired power plants
Boiler fly ash and flue gas recirculation
Denitrification and desulfurization process of coal powder furnace
Technical transformation of desulfurization in coal powder boiler furnace
Adding a calcium injection desulfurization system inside the furnace can serve as an auxiliary desulfurization system for power plants. Taking advantage of the low nitrogen combustion system, in terms of calcium sulfur molar ratio
When Ca/S=1.5, the desulfurization efficiency can reach 40%. Reduce the SO2 content in flue gas from combustion.
When using high sulfur coal, the calcium injection system in the furnace is put into operation for desulfurization, which can reduce the SO2 content in the flue gas entering the tail desulfurization system, alleviate the burden on the desulfurization system, and ensure that SO2 emissions meet the standard.
The calcium injection desulfurization system in the furnace has the advantages of low initial investment, short construction period, reduced investment and operation costs of the desulfurization system, suppression of high-temperature corrosion in the furnace and hydrogen sulfate ammonia corrosion in the air preheater, and easy comprehensive utilization of high calcium fly ash.
CFB circulating fluidized bed boiler desulfurization and denitrification process
Gas furnace denitrification and desulfurization process
Low temperature flue gas purification of hazardous waste furnace
Thermal oil furnace flue gas SCR+desulfurization process
化工窑炉及焦化炉烟气低温SCR+CFB脱硫工艺
Denitrification technology process of direct fired furnace sintering machine in steel plant
Layout position of direct fired furnace
The entire sintering flue gas denitrification system adopts:
Medium high temperature SCR denitration device+flue gas heat exchange device (GGH)+direct combustion furnace heating, the direct combustion furnace is arranged in the U-shaped flue, located in front of the ammonia spray grille.
Internal System Description of Direct Combustion Furnace
A direct fired furnace consists of three parts: a combustion system, a flue gas system, and a control system:
1. The combustion system consists of a burner, a combustion air system, a gas supply system, and an ignition system.
A burner: Two burners are set up in a staggered arrangement in the flue gas duct to facilitate uniform mixing of heated flue gas (facilitating uniform thermal expansion of the flue gas duct and uniform inlet temperature of SCR);
B Combustion air system: Under normal circumstances, flue gas is used as the combustion air,
In the fault state, switch to air assisted combustion;
C ignition system: using plasma ignition; Out of the world
2. The flue gas system consists of a flue gas diversion device, a combustion chamber, and a mixing chamber. The flue gas is divided into three streams by the diversion device, and two streams on both sides flow through the combustion chamber from the outside for preheating. Afterwards, it mixes with a stream of smoke in the middle and the high-temperature smoke generated by combustion in the mixing chamber at the rear;
3. The control system mainly includes: control of fuel gas, control of combustion air, control of outlet temperature of direct fired furnace, and safety interlock.
Polymer Denitrification Process for Biomass Boiler
Polymer SNCR denitrification process flow
The denitrification process of solid polymer is an in furnace denitrification process, which adopts a powder gas-phase automatic conveying system. Several suitable positions are selected at the flue gas outlet of the furnace and the high-temperature zone of the furnace to drill holes and inject polymer denitrification agents. NOx is reduced to N2 and H2O in the appropriate reaction temperature zone.
Technical characteristics of polymer SNCR denitrification process
1. High denitrification efficiency; As is well known, the denitrification efficiency of ammonia based SNCR is generally between 40-60%, while the denitrification efficiency of polymer SNCR can reach over 85% Up there.
2. Simple process, easy to use, flexible spatial layout; The standardized airflow mixing and conveying integrated device is not limited by the site and space of existing denitrification sites, and is particularly suitable for occasions with strict requirements for SCR denitrification sites.
3. The project requires a small one-time investment. The integration, serialization, and standardization of airflow mixing and conveying devices do not require on-site construction and installation, greatly reducing one-time investment compared to SNCR and SCR processes.
4. Denitrification consumes less energy and has lower operating costs. The power requirements for the process equipment are minimal, and a power configuration of 20 "30kW is generally sufficient for the entire process equipment. The dosage of polymer denitrification agent is the same or lower than that of ammonia based SNCR reducing agent. Generally, the cost of denitrification agent consumption is 30-50 yuan/ton of coal.
5. No harmful by-products, no secondary pollution formation; The reaction product of polymer denitrification agent is N2, CO2, and H2O do not produce any other organic compounds, do not produce harmful by-products, do not form ammonium salts, and there is no gas escape phenomenon.
6. Has energy-saving and cleaning effects. After using polymer denitrification agents, the accumulation of ash and coking on the boiler tube wall will be alleviated or removed, which accelerates heat conduction and reduces heat loss, thus achieving energy-saving and cleaning effects. Compared with the traditional SNCR denitrification process, the solid-state polymer denitrification process does not require the injection of process water into the furnace and does not consume latent heat of gasification, thus improving the combustion efficiency of the boiler.
7. The denitrification system has good safety. Compared with traditional SNCR denitrification processes, polymer SNCR denitrification processes do not use ammonia or liquid ammonia to reduce NOx, so there is no need to consider the safety issues caused by ammonia transportation and storage in process design. Therefore, the safety of SNCR in denitrification process is greatly improved.
Comparison of PCR denitrification and SNCR denitrification processes (considering a 75t/h circulating fluidized bed boiler)
Boiler flue gas whitening technology process
Boiler flue gas mercury removal technology process
Mercury, as a trace element in coal, is mostly discharged into the atmosphere with flue gas during the coal combustion process. The mercury entering the ecological environment can cause long-term harm to the environment and human health. Mercury in flue gas mainly exists in two forms: elemental mercury and divalent mercury compounds.
Elemental mercury is more difficult to remove from flue gas compared to divalent mercury compounds due to its low melting point, high equilibrium vapor pressure, and insolubility in water. The toxicity of mercury is greater than that of organic compounds, and a large amount of mercury invades and pollutes water bodies through dry or wet deposition of methylmercury. Mercury can cause changes in cell permeability, disrupt cell ion balance, inhibit nutrient entry into cells, and lead to cell necrosis. Mercury can accumulate in fish and other organisms and circulate into the human body, causing great harm to humans and poisoning plants, leading to leaf shedding and withering. Due to the long residence time and high toxicity of mercury in the atmosphere.
The average mercury content in coal from various provinces in China is 0.22mg/kg, indicating that the mercury content in coal is generally high and mercury is enriched in coal.
The melting point of mercury is -38.87% C, and it has strong volatility at room temperature, which makes it chemically different from other trace elements during coal combustion. In coal-fired power plants, raw coal first enters the pulverizing system. Coal generates heat during the crushing process, and a portion of mercury evaporates from the coal. Coal powder enters the furnace and burns at high temperatures, gasifying mercury in the coal into gaseous mercury (i.e. elemental mercury HgO). As the combustion gas cools, gaseous mercury interacts with other combustion products to produce oxidized mercury (Hg2+) and particulate mercury.
After combustion, a portion of mercury is directly retained in fly ash and ash residue along with the formation of ash residue; Another part of mercury is released into the flue gas in elemental form as mercury containing substances in coal decompose at high flame temperatures (over 1400C) Mercury accounts for 23.1%~26.9% in fly ash, 56.3%~69.7% in flue gas, and only about 2% in ash residue. Therefore, the key to controlling mercury pollution from combustion is to control the emission of mercury from flue gas into the atmosphere.
The control methods for mercury pollution mainly include mercury removal before combustion, mercury removal during combustion, and mercury removal from exhaust gas after combustion. At present, there is relatively little research on mercury removal during combustion both domestically and internationally. The main approach is to use improved combustion methods to reduce NOx emissions while suppressing some mercury emissions. The previous article introduced the technology of mercury removal from the tail gas after combustion, and this article introduces the technology of mercury removal before combustion. This is the legendary backstory, right.
Coal washing and coal heat treatment are simple and effective methods to reduce mercury emissions. Traditional coal washing methods can remove a portion of mercury from non combustible mineral raw materials, but cannot remove mercury bound to organic carbon in the coal. This can only transfer mercury from coal to coal washing waste, but it still has a positive impact on reducing mercury in flue gas. On average, 51% of mercury can be removed during coal washing.
Boiler flue gas recirculation and fly ash recirculation
Flue gas recirculation
Recycled flue gas is mainly used at medium and low loads. The flue gas is taken from the outlet of the induced draft fan and introduced into the furnace after passing through the recirculation fan. Recirculating flue gas accounts for 10-15% of the total flue gas volume. The flue gas recirculation fan adopts frequency conversion regulation to adjust the amount of recirculating flue gas according to operational needs. For every 1% recycled flue gas input, the reheated steam temperature increases by 1-2 ° C. At the same time, it is beneficial to reduce the oxygen content in the main combustion zone, lower the furnace temperature, and solve the problem of high NOx emission concentration at low loads.
Fly ash recycling
The fly ash recirculation technology can effectively solve the problems of high carbon content and low utilization rate of desulfurizer in circulating fluidized bed boiler fly ash, and has been applied in engineering: the fly ash collected by the dust collector is sent back to the furnace through the conveying device, and the unburned carbon particles in the fly ash are burned again in the furnace, while the calcined limestone particles that did not participate in the desulfurization reaction participate in the desulfurization reaction again. By adopting fly ash recirculation technology, the carbon content of boiler fly ash is significantly reduced, and the utilization rate of limestone is significantly improved. After installing the fly ash recirculation device in CFB boilers with capacities of 45t/h and 240/h, which burn smokeless coal, the carbon content of fly ash decreased by 5% and 17%, and the thermal efficiency of the boiler was significantly improved. The emission concentration of sulfur dioxide in the flue gas decreased from above 300mg/m3 to below 100m/m3
Boiler flue gas recirculation and fly ash recirculatio
Boiler combustion technology
The company has a high-quality debugging team and long-term accumulated debugging experience. Through experiments, various problems that occur during the operation of tangential combustion coal powder boilers, swirl burner coal powder boilers, and circulating fluidized bed boilers are accurately analyzed, and corresponding adjustments or rationalization suggestions are made to ensure the safe operation of the boilers and improve the economic indicators of the units.
The company has multiple combustion technology experts who can analyze various problems and provide customers with technical solutions or related suggestions through technical consultation or training.
Main content of combustion technology services
➢Boiler cold dynamic field test;
➢Boiler hot combustion adjustment test;
➢ Boiler subsystem performance diagnostic test;
➢Optimization test of ammonia injection in boiler denitrification system;
➢ Zhundong Coal Anti pollution Combustion Adjustment Test;
➢Technical renovation plan (including numerical simulation and thermal calculation);
➢Technical training
Operation and adjustment technical services
Switching from poor coal to bituminous coal
In order to improve the economic efficiency of the unit, the lean coal boiler will be retrofitted by burning or co firing bituminous coal, through the transformation of the powder production system and the wind and smoke system,
Through comprehensive measures such as combustion system modification, air preheater modification, and heating surface modification, a lean coal boiler can achieve full burning of bituminous coal without coking or abnormal changes in main parameters. After the renovation, the energy consumption and environmental protection indicators of the unit have been significantly improved.
Hot furnace smoke powder production
In recent years, with the rapid development of China's power industry, the stable supply of coal for electricity has been impacted to varying degrees. Increasing the proportion of lignite co firing can to some extent alleviate the dilemma caused by insufficient supply of thermal coal, but co firing lignite also brings a series of safety and technical issues. The problems of insufficient explosion-proof and drying capacity of the powder production system, as well as the decrease in the load capacity of the unit due to the low calorific value of mixed coal, are common. The application technology of the hot furnace flue gas system in the intermediate storage powder production system is relatively mature. It can not only solve the problem of tight coal supply, but also meet the requirements of boilers with a large amount of brown coal co firing, unit load capacity, powder production system drying output, and powder production system explosion-proof performance.
Anti high temperature corrosion and oxidation technology
Prevent high-temperature corrosion of boilers
High temperature corrosion has become a common problem that frequently occurs in large coal-fired power plant boilers, showing a rapid outbreak trend in the short term. High temperature corrosion of the boiler causes thinning of the water-cooled wall, and in severe cases, tube bursting accidents may occur. According to the investigation, the shutdown and repair time of domestic thermal power units of 300MW and above due to pipe burst accidents accounts for about 40% of the unplanned shutdown time of the entire unit. Therefore, high-temperature corrosion of boilers not only seriously affects the safe operation of boilers, but also causes huge economic losses to enterprises. By using new high-temperature corrosion protection spraying technology and retrofitting combustion equipment, the problems of coking, high-temperature corrosion, and contamination of heating surfaces can be completely solved
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