ABB boiler secondary system of risk control system
http://www.factoryautmation.comFurnace fuel burning rate, reduce the physical and chemical boiler control system ABB heat boiler control system ABB loss, as shown in figure 1, according to the boiler load condition, the secondary air damper control, improve the boiler combustion characteristics, to adapt to the change of the load, avoid the happening of boiler fire phenomenon.
According to each part of the role of the different wind, secondary air fuel is divided into the wind, the wind and the wind, respectively, using different ways to control, such as table 1, AA, BB2, BB2, CC for 4 layer auxiliary wind, A1, A2, B1, B2, C1 and C2 fuel wind for 6 layer, A, AB, BC for 3 layer oil auxiliary wind, OFA1, OFA2 to 2 layer burning wind.
1 control principle
Export into the secondary air from the blower air preheater heating, and then through the bellows control panel, from the second enters the furnace to bellows, each layer wind rooms are equipped with control panel, each wind chamber damper is equipped with a pneumatic actuators, is used to control the baffle opening, the wind chamber baffle opening the layer control, namely, on the same level of actuator synchronous movement, the reasonable distribution of the function of wind chamber damper is burner nozzle in each layer between the air distribution, to maintain stable economic combustion.
The table 1 and figure 1 shows that fuel wind and auxiliary and tuyere layout, space arrangement, in every time the wind powder on the airflow is equipped with fuel, wind is conducive to a pulverized coal flow wind mixed with fuel the earlier of the wind, fire has enough air to make pulverized coal and air flow; Senior secondary wind BB2, CC coal combustion needed to supply the upper air, supplement not burning pulverized coal burning in the hearth required air, at the bottom of the auxiliary air AA, BB2 in order to separate the pulverized coal burning, reduce incomplete combustion heat loss.
Oil auxiliary soon after oil gun export wind mixed with oil mist, strengthen the whole combustion process; Arrange the top 2 layer of overfire air vents, in order to realize the classification burning, burning wind with the upper burner nozzle, to reduce NOX effect is very obvious.
2 auxiliary air control
Auxiliary wind is the main part of the secondary air, its role is to maintain the chamber pressure and secondary air bellows pressure differential pressure on the set value, between the bellows/furnace pressure difference between the value is a function of the boiler load and use reflect the load size and change trend of the level of pressure, boiler auxiliary <a href="/searchfanan.html?search=system&select=7">system of risk control system is shown in figure 2.
Auxiliary system of risk control system for more than a single pulse output control system, as shown in figure 2, bellows and differential pressure signal between the furnace 2, including PT1503A and PT1503B, through the selection of SIGSEL block, to take the average AUX_PID controller, when the auxiliary wind baffle master station AUX_AOUT operation in automatic mode, the control system according to the bellows/furnace pressure difference value and bellows/furnace to proportional integral differential pressure deviation of measurement value of actual control, output control instruction, parallel control wall before and after the pulverized coal burner of multilayer auxiliary wind baffle and burner multilayer auxiliary wind baffle, to keep the furnace and the differential pressure between the secondary air bellows on the set value.
According to the runtime, the coal mill with the load may be different, and requires a different air distribution, therefore, each layer of auxiliary wind baffle have operator station, operators can be manually change the size of the bias in the site.
Auxiliary system of risk control logic as shown in figure 3, when one of the following circumstances, the auxiliary force cutting wind flap master operating station to manual mode:
(1) a big deviation control;
(2) the bellows with the furnace differential pressure signal bad;
(3) the level of pressure signal is bad;
(4) furnace purging;
(5) all auxiliary wind dampers for manual operation;
(6) FSSS to super chi whether open auxiliary wind baffle signal.
Fuel auxiliary air damper control system as shown in figure 4, the function f (x) fuel pressure are given, the corresponding relationship between the fuel wind baffle opening if A layer of oil gun putting-in-service proactively, fuel auxiliary function generator given wind baffle opening control instruction by switcher SWCH_A, soft hand controller, etc., on A layer 4 Angle of actuators, control fuel auxiliary air damper opening; If A layer of oil gun is not putting-in-service proactively by switcher SWCH_A, choose bellows differential control instruction, acting on A layer 4 Angle of actuators, control fuel auxiliary air damper opening, namely when the oil gun in the SPC ignition position, the corresponding auxiliary wind shields should be in the "oil gun ignition" position, and to modify the oil gun was put into the Numbers.
Oil auxiliary system of risk control logic as shown in figure 5, if the fuel pressure signal is bad, FSSS of corresponding oil auxiliary oil gun wind baffle whether mandatory cut to manually operation station,
When FSSS to whether a certain layer ignition instructions, by switching instruction BI08, BI09, BI10 and M03, given the corresponding reservoir auxiliary wind damper force on ignition, the opening of 35%; When fuel auxiliary wind baffle FSSS to whether pass a layer, by switching instruction BI05, BI06, BI07 and M04, given the corresponding reservoir auxiliary wind damper force; When FSSS to furnace purging signal whether, by switching instruction BI11 and M02, given the corresponding layer auxiliary fuel wind baffle keep 40% opening; When FSSS to super whether she fully open auxiliary wind baffle signal or bellows and high differential pressure chamber of a stove or furnace, by switching instruction BI12 and M01 setter, super chi fully open auxiliary wind baffle.
3 fuel control
In a wind around the nozzle arrangement has a fuel nozzle wind, the wind is also called Zhou Jiefeng, earlier than the auxiliary fuel wind wind power to participate in the boiler fuel burning, its purpose is to supply a wind powder with proper airflow, air supplement because of the pulverized coal concentration in combustion may occur in the early years of the lack of oxygen, the expansion of the ignition and combustion for pulverized coal and air flow, to prevent a wind deflection and pulverized coal segregation, avoid air flush furnace wall to form a large number of reducing gas and coking, high-speed Zhou Jiefeng can also enhance the ability of entrainment high temperature flue gas, fire, for pulverized coal and air flow to a wind vents also cooling and protection.
Fuel wind improper use, such as wind speed is too low or the air volume is too large, will make a jet and high temperature flue gas from the wind, adverse to the furnace combustion, fuel should typically wind and coal feeder speed is proportional to the feeding amount (representing).