The reliability and economy of pulverized coal furnace operation depend to a great extent on burner performance and aerodynamic conditions in the furnace. Good furnace aerodynamic conditions are mainly manifested in the following three aspects.
(1) There is enough hot flue gas from the combustion center to flow back to the root of the primary air-powder mixture jet, so that the fuel can be quickly heated and ignited after being injected into the furnace, and a stable ignition front can be maintained.
(2) The distribution of fuel and air is appropriate. After the fuel catches fire, it can get sufficient air supply and achieve uniform diffusion and mixing, so as to facilitate rapid combustion.
(3) There should be good flame fullness in the furnace, and a combustion center with moderate area should be formed. This requires that the airflow in the furnace should not be skewed, and the furnace wall should not be washed, so as to avoid stagnation zone and useless vortex zone. Each burner jet should not have violent interference and collision.
The main task of combustion adjustment is to ensure the safety and economy of boiler operation while meeting the steam quantity and qualified steam quality required by external load.
1、Elemental analysis of fuel
2、Sampling and industrial analysis of incoming fuel
3、Sampling of fly ash and slag,measurement of combustible content
5、Flue gas analysis data at furnace outlet (after superheater) and smoke exhaust, etc.
Heat conduction oil furnace is a thermal energy equipment that uses coal, oil and gas as fuel and relies on thermal oil as circulating medium for heating. When oil leakage occurs in heat conduction oil furnace, the following measures can be taken in order to use heat conduction oil furnace more correctly.
In order to prevent the organic liquid from leaking and burning, the welding needs to be strictly controlled. The quality of welding and NDT must meet the requirements of technical monitoring and safety regulations for organic heat carrier furnaces.
After an oil leak from a heat conduction oil furnace, first check whether the dewatering and exhaust heating speed is too fast, thermal oil heating water to generate steam, thermal oil low boiling point volatile mixture strong influence, leading to oil leakage in the elevated tank.
Due to the different equipment used for heating temperature or oil return temperature in heat conduction oil furnace, high temperature thermal oil quickly enters the cold oil in the refrigeration system, resulting in a large amount of evaporation of low-boiling substances and sharp expansion of volume, leading to oil overflow in the high tank. After that, we should look at whether it is caused by external reasons, such as circulating pump failure, sudden power outage, system vulnerability problems interrupt the circulating heating system. Because the furnace temperature can not fall in a short time, so the temperature rises rapidly, the high boiling point material and the low boiling point material of the heat conduction oil, because the high temperature directly washes the high oil leakage.
The welding requirements of heat conduction oil furnace are very strict, and the welded joints need to meet different requirements according to different compression components.
For the longitudinal ring weld of heat conduction oil furnace, sealing joint is 100% ray or 100% ultrasonic plus at least 25% ray inspection, and the current requirements of steam boiler and hot water boiler are basically the same, only add 100% ultrasonic plus at least 25% ray inspection. This regulation mainly considers 100% ultrasonic and 25% ray inspection, which can fully find the defects in the weld, meet the safety requirements and reduce the production cost.
For flaw detection of pipe butt joint on heating surface, the requirements are put forward according to different heating conditions. The difference in heat is radiant heat and convection heat. In the draft for consultation, 25 percent and 10 percent of flaw detection and spot checks are specified respectively. In the feedback, some units considered the requirements to be low and suggested changing them to 100% and 50%; Some organizations think the requirement could be lower. After analysis and research, we adopted the latter point of view, that is, not less than 10% of the radiation section of radiographic flaw detection and spot inspection; Not less than 5% in the convection section. The main consideration is that the butt weld of the heating surface tube should be gas shielded welding, and the quality is guaranteed. In addition, this procedure also stipulates the flaw detection method and the calculation of spot check rate, so that this procedure is more operable.
In addition to the cylinder of the gas phase furnace, the mechanical performance test should also be carried out. The cylinder of the liquid phase furnace, the heating surface tube of all the organic heat carrier furnace and the butt joint of the pipeline do not need to be carried out the mechanical performance test. Therefore, this regulation is only in the gas phase furnace batch production. In other cases, a test board is not required. The main consideration is the relatively low pressure of liquid phase furnace. At the same time, this regulation not only specifies the welding method, but also puts forward the requirements for the welding process evaluation, which can ensure the quality and performance of the weld.
After gas enters the burner, it needs to mix with a certain proportion of air, and then fully burn, including two parts of heat, one part is the physical heat brought by gas and air. In simple terms, it is the heat it carries, and more generally it has a certain temperature; The other is heat from chemical reactions; The two parts of heat together determine the temperature of the flame.
The flame temperature of the burner seems to be easy to calculate, but it does not solve this problem, because the premise of this calculation is that the combustion process is carried out in a hot state, that is, both kinds of heat are used for the flame itself. This temperature engineering is called the calorimeter temperature, and the actual temperature is definitely not this temperature.
Generally speaking, the theoretical combustion temperature increases with the heating value of gas. When there are more heavy hydrocarbons in gas, the calorific value is higher and the theoretical combustion temperature is also higher. However, the phenomenon that the combustion temperature of low calorific value combustion is higher than that of high calorific value gas cannot be ruled out.
In addition, the excess air coefficient has a great influence on the flame temperature. The excess air coefficient is too small, the combustion is insufficient, the combustion heat loss is large, the theoretical temperature decreases; In any case, if the air coefficient is too large, the corresponding increase in combustion products will decrease the theoretical temperature, and this factor has been explained in theory.
The flame temperature is also related to the preheated air, the temperature increases, the enthalpy increases, the theoretical temperature increases.
The selection of natural gas burner is a very professional process, which needs to be established on the basis of clear customer needs. Fuel type, heat requirement, equipment type, etc. are very important to the choice of burner.
One is the burning nozzle power problem. Burner manufacturers list several common models for kw unit commonly, many customers will subconsciously kw associated with electricity, as is known to all, is the international standard unit, as the power unit is commonly used in electrical equipment, but not only in watts, kw electric equipment, such as boiler, part of the internal combustion engine in watts, too. Some engineers may be familiar with units such as card and large card, which may be easy to understand in large card units. In fact, a card is a unit of energy. If the unit is calories and calories, strictly speaking, it should be said that the number of calories per hour is a representation of power. Si conversion is generally calculated as 1 kw.h equal to 860Kcal equivalent. The choice of burner power should be determined according to the heat you need, the area of the combustion chamber and the operating temperature. For example, if you used coal instead of natural gas before and you need to know how much gas is consumed per hour or per day to calculate the heat when using coal, then the burner power problem can be easily solved.
The type of application equipment is also very important, different heating equipment to choose different combustion equipment, which will involve the flame type of the burner, the layout of the burner and the combustion type of the burner. EBICO will choose the right burner according to the burner and kiln equipment to achieve energy-saving combustion. When customers determine their own combustion control methods, not only to be price oriented, but also more consultation, more consideration.
When the gas boiler is in normal operation, the fuel flame is durable and stable. However, if there are some unexpected situations, it is easy to cause the phenomenon of "tempering" and "defire", which will seriously affect the safety of gas boilers.
Compared with air, the gas fuel concentration of gas boilers is at the combustion limit. If the flow rate of flammable gas in the burner is lower than the burning rate, the flame will propagate toward the fuel source and a so-called "tempering phenomenon" will occur. The study found that the higher the furnace temperature of gas boilers, the faster the flame propagation speed, the easier it is to produce tempering. Due to the occurrence of tempering in the burner, the damage to the burner is great, and the burner will explode when it is serious. Compared with tempering phenomenon, the condition of detempering phenomenon is that the flow rate of combustible gas at the outlet of the burner is higher than the speed of combustion, leading to the combustion of fuel in the direction of the original burner. This phenomenon is called "deignition". It is found that when the gas boiler is under a low load condition, the boiler is easier to deignite.
Through testing, if it is caused by too low gas pressure, it is necessary to carry out a thorough inspection of the gas pipeline of the gas boiler. If it is caused by too high gas pressure, it is necessary to carry out normal operation of the regulating valve on the whole gas pipeline, strictly check the total air pressure on the gas pipeline and the pressure before the burner, as well as the valve opening of the burner. If it is caused by the decrease of the total pressure of the gas supply pipeline in the gas boiler room, it is necessary to contact the gas supply station in time to quickly improve the gas supply pressure. If the intake pressure is normal, it is necessary to test whether the pressure regulator is normal.
After the completion of the transformation of the gas burner system, the operator needs to follow up the debugging in time. After the completion of the debugging, the professional and technical personnel are required to accept and check the gas burner, so as to ensure that all the indicators and parameters are in line with the practical needs of operation and production.
1.Improve waste placement time
Before the waste goes into the incinerator, we should increase the time for the waste to sit, generally more than 5 days. Before incineration, completely disperse the moisture on the surface of the garbage, reduce the humidity of the garbage, reduce the harmful components in the garbage, prevent the garbage from burning completely, and more effectively reduce the garbage in the incinerator because of high humidity and can not burn, resulting in machine blockage or even shutdown.
2.Adjust the reasonable speed of garbage release
When waste is fed, the Angle between the hopper and the incinerator storage room should be reasonable to prevent uneven weight and density of waste when it enters the storage room. During the operation of the incinerator, the temperature, wind, garbage burning rate and other indicators in the incinerator are closely paid attention to, and the garbage feeding rate is determined according to these data. This can effectively prevent the damage of solid waste caused by fast feeding speed to the performance of the incinerator, improve the operation efficiency of the incinerator, and reduce unnecessary energy consumption in the operation process.
3.Complete garbage sorting in advance
Before entering the incinerator, if the garbage composition is too complex or chemical waste is too large, it is recommended to carry out simple classification treatment. Garbage of similar nature should be incinerated together, and different garbage should be incinerated separately. According to the different physical and chemical properties of the waste, different incineration schemes should be developed. Although the classified incineration method reduces the work efficiency of the waste incinerator, it ensures the operation efficiency of the incinerator and protects the related systems in the incinerator from the erosion and destruction of harmful flue gas.
1.The traditional combustion power is small, heat storage performance is poor.Combustion power of Energy-saving forging furnace is stable, heat storage performance is strong, up to 80%,reduce nitrogen dioxide emissions.
2.The traditional gas supply system without frequency conversion regulation, easy to produce peroxygen combustion and flame instability; The new energy saving gas supply system uses furnace pressure detector to control fan frequency conversion, adjust and control the mixture of air and gas ratio, so that the burner burns stably.
3.The traditional smoke exhaust way is not adjusted, resulting in unstable furnace combustion.The new furnace adopts furnace pressure detector for smoke exhaust, which controls the frequency conversion adjustment of the exhaust machine to control the amount of smoke exhaust, so that the furnace can control a certain micro-pressure operation, reduce the pressure fire jumping.
4.traditional fire and heating time is long.The new forging furnace has no fire jumping phenomenon and high thermal efficiency.
5.The old combustion system does not have a separate ignition fan, resulting in unstable wind pressure of the ignition gun, which is not easy to fire quickly, generating alarms and system locking. The new ignition system is equipped with a separate ignition fan, so that the air - fuel ratio of the ignition gun is stable in a controlled range, and it is not easy to blow out and ignite. In addition, in terms of price, energy saving forging furnace is more expensive, but later energy saving cost is much greater than the price of equipment.