Discharge of non-condensable gases from the tower top?
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If distillation is operated at atmospheric pressure, must the non-condensable gas outlet of the top condenser remain open? What should be done if the factory doesn’t have an emission control system? Please give some advice, thank you!
It must remain on at all times; otherwise, pressure buildup will occur. Appropriate treatments such as pressure swing adsorption or membrane adsorption are required to bring it to the **specified standards before it can be released.
In atmospheric pressure distillation, it is necessary to keep the tower vent open; otherwise, there is a risk of explosion. For non-condensable gases, options include treating them as gases, or using activated carbon absorption, as well as absorption with water, liquid alkali, acids, etc., or employing methods such as ion exchange for adsorption. If that doesn’t work, it can be collected and then introduced into a flare or boiler for combustion. Avoid environmental pollution!
I guess I have to keep learning* for a long time! :L
If sensitive to pressure, a control valve should be used to maintain the operating pressure; combustible gases should be sent to a flare, while non-toxic and non-combustible gases should be released at high altitudes
The plant does not have a flare system, and the materials in the system are toxic as well as flammable and explosive. What should be done in such a situation? Can the non-condensable gas discharge pipe be connected to a water seal tank?
There is danger inside the water seal tank; if you’re not completely sure, the tank isn’t safe**
If there is a heating furnace, a burner can be placed in it to burn it off.
The tower vent must be opened; the reasons have been explained by others. Your non-condensable gas contains toxic and flammable materials, so it cannot be released directly. A small exhaust gas absorption tower can be built to meet the emission standards.
Water is effective in absorbing water-soluble gases; for water-insoluble flammable gases, an incinerator can be installed (one that recovers waste heat or one that does not – either works), which is more cost-effective than using a flare!!
It is recommended to use a breathing valve, as it is more reliable. For combustible gases, a flame arrester can also be considered; the gas that emerges can be collected for reuse or burned directly (of course, without causing environmental pollution)
We adopted two processes to handle this situation: First, one that is directly connected to the tower, with a nitrogen balance system in place； Second, install balance pipes in the distillation system to connect with the water seal, and add a vent tower; an air blower at the bottom of the tower is used to introduce air for dilution. This process requires a low volume of non-condensable gas to be discharged.
The non-condensable gas from the tower top condenser can be returned to the process. The most common is to return to the condensate collection tank at the top of the tower. Top condensate collection tanks generally have bypass pressure control. It’s a very simple solution!
Could the friend on the 16th floor explain in detail? Thank you
I’m sorry; I’ve never encountered such a situation before. Since the operation is at atmospheric pressure, there should not be much non-condensable gas inside. There is also no flare system, so there won’t be many toxic or irritating gases either. Emission to the atmosphere at high altitudes could be considered, and if conditions permit, secondary reprocessing might be an option as well. It’s dangerous to allow water to enter the tank. It’s best to install a buffer tank or a condensate recovery tank before the discharge system, as this can also prevent the release of non-condensable gas. Always keep it open :handshake