How can sealing be achieved during the unloading process of methanol vehicles?
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Methanol is toxic; when unloading it from vehicles, the air inlets on the top of the methanol tankers are usually left open, which inevitably leads to the release of methanol gas. Discussion: How to solve this problem to achieve complete sealing during methanol unloading? Add a nitrogen seal to the tank truck? Are there any other more clever measures?
Use liquefied gas unloading; connect a vapor line, or employ an oil and gas recovery device；
That means the methanol tank truck would need to be modified to resemble an LPG tank truck, with not only a liquid-phase interface but also a gas-phase interface, and this seems like a rather substantial amount of work. Are there any other faster and more reliable methods?
Many manufacturers in this field are now producing closed-loading and unloading vehicles; you can inquire about them. Additionally, for simple engineering solutions, it is recommended to unload the material at the bottom; the open end of the tank truck can be sealed with a rubber or other material-based sealing cap. A vapor line should be connected to the top of the vapor space in the methanol feed tank, thereby creating a vapor connection between the tank truck and the receiving tank.
Well, it’s a solution. If the open hatch of the tank vehicle is sealed and a gas pipe is added, it can be connected to the methanol tank, or nitrogen can be introduced directly – either approach should work. Currently, most manufacturers focus on making loading in sealed containers convenient; there are still few systems for unloading in a sealed manner (except for liquefied hydrocarbons).
How is the oxygen content in exhaust gases taken into account? Exhaust gases can relatively easily reach the explosion limit. Operational hazard.
I understand that it should be sealed before unloading, so that the tank truck is connected to the receiving tank. Receiving tanks now all require nitrogen sealing. Under normal operation of the storage and transportation system, I think that only during the sealing process after shutdown does the liquid phase in the tank truck come into contact with air. Will there be significant changes during this process? It should mainly be the volatilization of methanol, right? I’ve never been involved in production, and this is something worth noting. .
A few years ago, **it didn’t seem like there was a requirement for closed-unloading; presumably, there wasn’t much incentive to do so from any perspective. . .
A breathing valve can be installed on the tank truck
Methanol is generally unloaded from the top, so submersible pumps together with dip pipes are standard equipment; in cases where both gas and liquid dip pipes are used, sealing caps can be installed for additional protection. Due to unloading, the sealing cap will become tighter and tighter, so there is generally no need to worry about gas leakage.