Methanol in crudes

[MortenA]

I work in upstream and we would like to implement a cold process as water dew point control (and HC) using methanol as the freezing point depressant/hydrate inhibitor. We hear that this could cause downstream problem and/or a price penalty. I would therefor like to hear from people who works in downstream what causes the issues with methanol and is it true that we could expect a price penalty (i know i could ask internally but thats often slow business )

Best regards, Morten

 

[blacksmith37]

I can't answer your question; But it will depend on how the crude is treated. Does it go to heated desalter ( alcohol may boil off) , Otherwise the alcohol will concentrate into the water phase - not go with the oil. I never heard of a problem with alcohol; chlorinated solvents which show up in crude are big trouble.

 

[Alexander R.]

I can't also speak for downstream. But in upstream, methanol has some negative effect on produced water.
- Methanol tends to increase solubility of hydrocarbons in water. Therefore, excessive amount of methanol may increase amount of hydrocarbons that are dissolved in water and are not removed by conventional produced water treatment equipment, which mainly deals with dispersed oil.
- Methanol molecules tend to reverse polarity of coagulant chemicals and, thus, reduces oil droplets coalescence. This, in turn, will reduce the efficiency of separation equipment, and consequently more small droplets will leave together with produced water.
- And minor thing is that presence of dissolved methanol in water will reduce slightly a density of the water phase, thus, again reducing the efficiency of the gravity based separators.

 

[georgeverghese]

Methanol is often quoted to be a poison for mole sieves, and there are some downstream refinery operations where mole sieves or mole sieve like compounds are used : (a)in isomeration units for LSR gasoline stream octane improvement (b)zeolites used in crude FCC units (b) in final drying of LPG streams. (b) may not be applicable in your case.

Can see why you wish to consider MeOH for this gas - condensate hydrate inhibition application, but also consider toxicity and flammability. There will also be trace amounts of MeOH in the water stream produced from the MEG regeneration unit, which will not be acceptable for disposal at sea in most jurisdictions.

MeOH is typically only used for short term startup hydrate inhibition purposes for these reasons.

 

[MortenA]

@georgeverghese
Thanks for your input, thas something i can work with We only deliver to one point because its via a pipeline so we can discuss this with the downstrem operator. I agree with the other posters that most of the MeOH will end up in the water. We know that this will not cause big problems in the sewage treatment plant.

Best regards, Morten