The core parts of the gas boiler are two, boilers and stoves. The boiler is the heat-replaced body and the furnace is the burner that mixs gas and air, ignites and releases heat. Many users choose the boiler to look only at the boiler and do not focus on the burner, resulting in nox excesses, fire instability and high failure rates. The choice of the burner is good and directs the environmental compliance, operational efficiency and maintenance costs of the boiler。
What's a burner for
The work of the burner is simple and mixs gas and air in an appropriate proportion, and fires into the oven, creating a stable flame. However, it is not easy to do so. It involves fluids, combustion, and automatic control in a number of areas。
A good burner meets a few requirements. The flame shall be stable, unfired and not refired, and the shape and length of the flame shall be adapted to the chamber size when the load changes. Gas and air mix is sufficient, incomplete combustion losses are small and carbon monoxide emissions are low. The reconciliation is wider, i. E., the ratio of maximum to minimum, and can also stabilize combustion at low loads without frequent activation. Nitrogen oxide emissions are low and meet local environmental requirements. Maintenance needs to be easy, loss-prone and faulty。
The burner is divided into three types of fire, two segments and proportion. There is only one active slot for a single fire, suitable for a small capacity boiler; two sets of fire are large and large, which is more flexible than a single fire; and the ratio adjustment allows for a continuous flow of power, a high temperature or pressure control accuracy, suitable for an occasion where the steam parameters are required to be stable. Large-capacity boilers are generally proportionally regulated burners。
What's the difference between a regular burner and a low nitrogen burner
Nitrogen oxide emissions from ordinary burners are usually between 120 and 200 mg/m3 and are used in areas where environmental requirements are low. But now, in many places, gas boilers are required to emit less than 30 mg/m3 of nitrogen oxides, which cannot be reached by ordinary burners, and must use low nitrogen burners。
The low nitrogen burner is not simply a different brand, and its structure and combustion methods are tailored. Nitrogen oxides are produced in three main ways: heat, fast and fuel. Nitrogen oxides in gas boilers are mainly of thermal type, i. E. Nitrogen in air is generated at high temperatures and oxygen reaction, and the higher the temperature, the greater the generation. So the idea at the heart of low nitrogen combustion is to lower the peak temperature of the flame and reduce the length of stay of the flue gas in high temperatures。
There are several techniques commonly used in low nitrogen burners. Inert gases in flue gases are reduced in flame temperatures while oxygen concentrations are reduced and nitrogen oxides are significantly reduced as a result of their recycling, which leads a portion of the smoke back to the burner entrance and then burn when the gas air is mixed. External flue-recycling requires pipe and wind machines, and internal flue-recycling is achieved by the structure of the burner itself, without additional equipment。
Full pre-combustion is sufficient mixing of gas and air before entering the furnace, fast combustion, short flames, even temperature distribution, low peak temperature, and emission of nitrogen oxides to below 30 mg. Full premix burner requirements are high for gas pressure and cleanliness, requiring filters and pressure valves, and the head of combustion is regularly cleaned or otherwise easily clogged。
Classized combustion is the transport of gas and air into different stages, which can be effective in reducing nitrogen oxides by first burning under aerobic conditions, reducing the temperature of the flame, and then replenishing the air to complete the combustion. Many low nitrogen burners combine several techniques and work better。
The low nitrogen series of the kono boiler with low nitrogen burners combined with flue gas recycling and grade combustion techniques stabilized below 30 mg/m3 of nitrogen oxide emissions, with partial models below 20 mg. The burner and boiler body are designed as one unit, and the flame shape and chamber size match, and there will be no flame brushing the urchin. Many users change their own burners, and the flames are too long to lick the trunk, or too short to change the heat, because no matching design is made。
What about the nox emission standards? Look
Environmental requirements vary from region to region, and local standards are to be understood before choosing a burner。
In the northern regions of beijing, tianjin, hebei, shandong and henan, the emission limit for nitrogen oxides from gas boilers is mostly 30 mg/m3 and some focus areas require lower requirements, such as 20 mg or even 10 mg. The long triangle and the pearl triangle are also being tightened, and many cities have requested less than 30 milligrams. The western region is relatively liberal, with some remaining 80 or 150 mg。
Standards change, and now loose places may tighten in a few years. It is recommended that excess quantities be retained in the selection of burners, such as the local requirement of 80 mg and the direct selection of 30 mg low nitrogen burners, which would not cost much, and that standard upgrades not be replaced in the future. If the standards change for re-engineering, the shutdown loss plus the cost of re-engineering is much more expensive than the low nitrogen at the outset。
It is also important to note that emissions from low nitrogen burners are measured under rated loads and that nitrogen oxides may rise at low loads. The type is selected to confirm that the burner is capable of meeting the standard throughout the range of the regulation, rather than only at full load。
Molar selection points
The selected burner first looks at power, matching the rated heat load of the boiler. The maximum contribution of the burner is slightly greater than the rated capacity of the boiler, leaving a residual of 10 to 20 per cent, which cannot be picked in time, otherwise the gas pressure fluctuations will not keep pace. However, it is not possible to choose too much, with cars in greater mara, which burn in a low load and are prone to frequent stops。
The reconciliation ratio is the second point. If the boiler's load fluctuates significantly, for example when the amount of gas used is small, it is necessary to select the burner that regulates the width, such as 1:5 or 1:10, which can also stabilize the combustion at low loads. If the load is more stable, the reconciliation is sufficient for 1:3. The wider the reconciliation, the higher the burner price, the greater the selection according to actual demand。
Branding and services are also important. The burner is a multi-depreciable device, with the potential for failure of nozzles, electrodes, wind machines and electromagnetic valves, the choice of a brand with large market holdings, the availability of spare parts and the ease of repair. Imported brands such as leah road, beetho, oco are of stable quality but expensive and have expensive spare parts; national product plates have made great progress in recent years, with high value for money and high responsiveness to services. The burners in the kono boiler can choose different brands based on user needs and are tested for matching before leaving the plant。
It also depends on the ease of maintenance of the burner. The details of these daily maintenance are important only after a long period of time. Some burners are structurally complex and take half a day to dismantle, and maintenance costs are high。
Common malfunctions and routine maintenance
Most of the burner malfunctions were related to non-maintenance. The lack of ignition is the most common cause, possibly because of the failure of the ignition electrode carbon or position, the inability to open the gas-based electromagnetic valve, the fume detectors, and the failure of the wind-pressure switch. The check is sequenced to see if there is gas, then the ignition electrodes, and finally the flame detection and wind pressure。
Another type of failure is the return fire and the breakout. The return fire is the return of the flame to the burner's internal combustion, which can easily burn the head of the burner because the gas pressure is too low or the head of the burner is clogged; the discharge of the fire is the discharge of the fire from the burner's head, which can easily be extinguished because the gas pressure is too high or the wind is too high. In both cases, gas pressure and wind doors are adjusted to clean the head of fire。
There are a few things to do in daily maintenance. Regular clean-up of carbon and impurities on burn head and nozzle and higher frequency of clean-up where the gas quality is poor. Check the break and position of the ignition electrode, and the carbon will be worn. Check if the gas-fired electromagnetic valve leaks and the seal is ageing to change. Clean up the dust on the windmills and load the wind. Validation of flame detectors and pressure switches to ensure proper protective function。
Although the burner is a part of the boiler, it determines whether the boiler is safe, stable and environmentally friendly. Picking the burner, doing the routine maintenance, and running the boiler saves you; the cheap one, with two failures in three days, the environment is not up to standard and the price is not lost。
