RTO burner issues
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I would like to ask what will happen if the ratio of natural gas to compressed air in the RTO burner is not adjusted properly? If the proportion of natural gas is too high, will the unburned natural gas burn again in combination with the air that enters as exhaust gas? What happens if the proportion of compressed air is too high? Just burning more natural gas? We have a device here that reduces the frequency of the exhaust fan, and our on-line monitoring equipment shows that the methane levels are significantly high. What is the reason for this?
What you’re referring to is the relationship between the gas volume and the air supply volume; the general empirical value is that the ratio of natural gas to air is 1:22.4. Also, it’s important to consider whether your incinerator uses segmented air supply or only one air supply route.
The temperature inside the RTO furnace is over 800 degrees; how is it still possible to detect methane in the exhaust gases that come out? It must have burned up inside the furnace along with the air that brought in the exhaust gases. In addition, there is a proportional control valve assembly on the burner’s gas pipeline, so that an increased amount of combustion air does not result in more gas being burned.
It was actually detected. I don’t know why either; simply by lowering the frequency of the exhaust fan, the methane level increased. There’s another unit that used to use propane, but now it’s switched to natural gas, and without adjusting the proportional valve, the methane level also became high during operation
What he meant is likely total hydrocarbons other than methane
It’s possible that the zero point of your instrument has drifted, causing the fan frequency to decrease and the resulting value to increase
Yes, it’s the high methane level detected among the non-methane hydrocarbons
Under normal circumstances, reducing the frequency of the exhaust fan should result in a slight increase in the RTO treatment efficiency. Your RTO should be used after the zeolite wheel concentrator; reducing the fan speed increases the concentration of waste gases. Additionally, there may be leaks in the RTO switching valve, which also leads to an increase in the VOCs concentration of the purified exhaust gases coming out of the RTO. The methane/non-methane hydrocarbons detected by the FID online detection system are a single category, and not actual methane. The reason is that the purification of VOCs in the exhaust gases does not meet the standards; it may require inspection and maintenance.
I’ve encountered similar problems, but the reason isn’t what the experts say
Is the burner integrated or separate? Typical RTO burners are equipped with integrated burners, which have a PLC-programmed control logic; the air-fuel ratio in such burners is fixed. Additionally, the proportion of natural gas should be under PID control in conjunction with the temperature in the RTO furnace, and there should also be a safety shutdown mechanism; for example, if the furnace temperature rises due to a low flash point point, the natural gas supply should be automatically shut off. If you still rely on manual control and adjust the natural gas flow rate arbitrarily, the risks increase significantly. Also, which exhaust fan are you referring to? Does it refer to before entering the RTO furnace or after it? The control interlock logic in the two locations is also different; typically, the interlock system is designed to work in conjunction with the RTO furnace pressure control, in order to maintain the furnace pressure within a certain range.
What the master said is correct. But when we reduce the frequency, it’s during times when we’re not in production; the concentration of exhaust gases is already low. Reducing the frequency also helps to save natural gas