[Weekly Topic] What are the precautions when operating gas boilers? (December 19---December 31)

This post was last edited by tangfangzh on 2011-12-20 at 16:33. It is a 23t/h gas-fired steam injection boiler; its current output is 18t/h with a gas consumption of 1718 Nm3/h. The goal is to increase the output to 20t/h. Fan SAACKE MHI45-70/4, 21500 m3/h, 5200-6520 Pa. The original fan does not have sufficient airflow to increase the output; the manufacturer of that fan is unwilling to remove it. According to available information, it would be better to connect another identical fan in parallel. I seek advice on this matter. A new thread titled “Insufficient Power” has been created; everyone is welcome to discuss it in that new thread

This post was last edited by dongjiang1001 on 2011-12-20 at 21:17. Why isn’t anyone responding? We have just installed a boiler that uses gas for combustion, and we would like to get some information on it.

It’s better not to do that; be careful else the tube might burst. A 23t/h gas-fired steam injection boiler operating at 80% capacity has an output of 18 T/h. If the dryness level can be reduced, reduce it to the lowest safe level – safety first.

Does the boiler have an exhaust fan? Maybe we should consider adding an exhaust fan?

(1) To prevent gas explosion accidents, gas boilers not only need to have their furnace chambers and flue gas passages purged before startup, but also their gas supply pipelines need to be purged. Inert gases such as nitrogen and carbon dioxide are generally used as purging media for gas supply pipelines, while air at a certain flow rate and velocity is used as the purging medium for boiler furnaces and flues. (2) For gas boilers, if ignition fails on the first attempt, it is necessary to purge the furnace flue again before attempting ignition a second time. (3) During the combustion adjustment of gas boilers, to ensure combustion quality, it is necessary to monitor the components of the exhaust gases in order to determine the excess air coefficient and the extent of incomplete combustion. Generally, during operation, the carbon monoxide level in gas boilers should be below 100 ppm, and when operating at high load, the excess air coefficient should not exceed 1.1–1.2 ； Under low-load conditions, the excess air coefficient should not exceed 1.3. (4) In the absence of measures such as anti-corrosion treatment or condensate collection at the rear of the boiler, gas boilers should try to avoid operating for extended periods at low load or under low parameters. (5) For gas boilers fueled by liquefied gas, special attention should be paid to the ventilation conditions in the boiler room. Since the specific gravity of liquefied gas is greater than that of air, in the event of a leak it can easily cause the liquefied gas to condense and spread on the ground, leading to severe explosion accidents. (6) The boiler operators should always pay attention to the opening and closing status of the gas valves. The gas piping must be leak-free; if any abnormalities occur, such as an unusual odor in the boiler room, the burner should not be turned on. The ventilation system should be checked promptly to eliminate the odor, and the valves should be inspected – only after everything is normal can the system be put back into operation. (7) The gas pressure should not be too high or too low; it must operate within the specified range, with the specific parameters provided by the boiler manufacturer. When the boiler has been running for some time and it is found that the gas pressure is below the set value, it is necessary to contact the gas company promptly to check whether there has been any change in the supply pressure. After the burner has been in operation for some time, it is necessary to check regularly whether the filters in the pipelines are clean. If the air pressure drops significantly, it may be due to an excessive amount of impurities in the gas, which has caused the filters to become clogged; in such cases, they should be removed and cleaned, and the filter elements replaced if necessary. (8) After being out of service for a period of time or after inspecting the pipelines, when putting them back into operation, the vent valve should be opened to release air for a certain period; this duration should be determined based on the length of the pipelines and the type of gas. If the boiler is out of use for an extended period, the main gas supply valve should be turned off, as well as the vent valve. (9) The **regulations regarding gas must be complied with. Fire should not be used arbitrarily in the boiler room, and welding or gas welding operations are strictly prohibited near gas pipelines. (10) The operation instructions provided by the boiler manufacturer and the burner manufacturer must be followed, and these instructions should be kept in a location where they can be easily accessed for reference. In the event of any abnormalities or when the problem cannot be resolved, it is necessary to contact the boiler manufacturer or gas company promptly, depending on the nature of the issue, and repairs should be carried out by professional technicians.

The 1.130t/h positive-pressure boiler is prone to coking during operation due to poor steam atomization. Since it is not possible to remove the coke from such a boiler, the only option is to shut down the boiler in order to do so, which is quite troublesome. Later, imported burners were used, and the situation improved. 2. During startup, tail burning occurred due to improper make-up air.

(1) To prevent gas explosion accidents, gas boilers not only need to have their furnace chambers and flue gas passages purged before startup, but also their gas supply pipelines need to be purged. Inert gases (such as nitrogen and carbon dioxide) are generally used as the purging medium for gas supply pipelines, while air at a certain flow rate and velocity is used as the purging medium for boiler furnaces and flues. (2) For gas boilers, if ignition fails on the first attempt, it is necessary to purge the furnace flue again before attempting ignition a second time. (3) During the combustion adjustment of gas boilers, to ensure combustion quality, it is necessary to monitor the components of the exhaust gases in order to determine the excess air coefficient and the extent of incomplete combustion. Generally, during operation, the carbon monoxide level in gas boilers should be below 100 ppm, and when operating at high load, the excess air coefficient should not exceed 1.1–1.2 ； Under low-load conditions, the excess air coefficient should not exceed 1.3. (4) If no anti-corrosion measures or condensate collection systems are in place at the rear of the boiler, gas boilers should try to avoid operating for extended periods under low-load or low-parameter conditions. (5) For gas boilers that use liquid gas, special attention should be paid to the ventilation conditions in the boiler room. Since the specific gravity of liquefied gas is greater than that of air, in the event of a leak it can easily cause the liquefied gas to condense and spread on the ground, leading to severe explosion accidents. (6) The furnace operators should always pay attention to the opening and closing status of the gas valves. The gas piping must be leak-free; if any abnormalities occur, such as an unusual odor in the boiler room, the burner should not be turned on. The ventilation system should be checked promptly to eliminate the odor, and the valves should be inspected – only after everything is normal can the system be put back into operation. (7) The gas pressure should not be too high or too low; it must operate within the specified range, with the specific parameters provided by the boiler manufacturer. When the boiler has been running for some time and it is found that the gas pressure is below the set value, it is necessary to contact the gas company promptly to check whether there has been any change in the supply pressure. After the burner has been in operation for some time, it is necessary to check regularly whether the filters in the pipelines are clean. If the air pressure drops significantly, it may be due to an excessive amount of impurities in the gas, which has caused the filters to become clogged; in such cases, they should be removed and cleaned, and the filter elements replaced if necessary. (8) After being out of service for a period of time or after inspecting the pipelines, when restarting operation, the vent valve should be opened to release air for a certain period; the duration of air release should be determined based on the length of the pipelines and the type of gas. If the boiler is out of use for an extended period, the main gas supply valve should be turned off, as well as the vent valve. (9) The **regulations regarding gas must be complied with. Fire should not be used arbitrarily in the boiler room, and welding or gas welding operations are strictly prohibited near gas pipelines. (10) The operation instructions provided by the boiler manufacturer and the burner manufacturer must be followed, and these instructions should be kept in a location where they can be easily accessed for reference. In the event of any abnormalities or when the problem cannot be resolved, it is necessary to contact the boiler manufacturer or gas company promptly, depending on the nature of the issue, and repairs should be carried out by professional technicians.