Solvent Extraction Plan for Vegetable Oil

Why solvent? Doesn't squeezing them work, followed by straining or filtering?

Hi Tornado,

Your reply got me thinking...

I am not an extraction expert by any means, but I do understand the basic principles involved.

Looking around on the Web, I found this (from here):

Because most press or expeller processes overheat the meal and
leave too much of the high value oil in the seed cakes, methods
of extracting the oil with solvents were developed. Seeds (like
soybeans) with low oil content are processed by solvent methods
alone. In other cases, presses are used first to extract part of
the oil; then solvents extract the oil that remains in the seeds.

Because of their efficiency, processes employing solvents to
extract vegetable oils in large quantities are in wide use, and
solvent extraction equipment is readily available commercially.
The basic technology of solvent extraction is simple, but great
care should be taken in deciding whether and where it can be
used.

Solvent extraction of vegetable oils, which recovers more oil
than earlier methods and leaves more usable meal, begins to be
economically attractive where large quantities of seed can be
processed (at least 200 tons per day for continuous-feed processes);
where storage, transportation, power, water, and solvent
supply are adequate; and where occupational safety and training
standards can be enforced. There are solvent extraction plants
with capacities of up to 4,000 tons per day.

It really is amazing how much more we can learn, having the WWW at our disposal (than before it was available).

Mike

Thanks! I'm not surprised that a solvent process could extract more oil, but I would then wonder about separating the solvent from the oil. I'm thinking of the first cold pressing of super-extra-virgin olive oil, followed by solvents to wring out the last available drop.

(I have a cartoon around here of extra virgin olive oil at $10 per bottle next to an equal bottle of extra slut olive oil at $1.) [Funny Times]

Hmmm... I guess I never pondered what extra virgin really meant, let alone super extra virgin.

On a serious note, I did some work at PNNL using supercritical CO₂ (>73.8 Bar AND >304.2 K) to perform essential oil and similar extractions. Interesting work; supercritical fluids have viscosities in the same range as gases and densities in the same range as liquids. Low viscosity enables faster penetration into the plant fiber matrix and high density enables higher (mass) solubility. Decrease the pressure of the oil-laden CO2 and the oil drops out, is collected, and the CO2 can be compressed and used again.

Interesting! I was thinking of petro-distillate solvents rather than something like CO₂, where I wouldn't worry about residues. I worked at PNNL for about a year, but it didn't pan out long-term. My wife and I want to retire to the Tri-Cities area, where we have many friends.

Wow! That's where most of my family is, and where I want to return within about 5 years. I lived most of my adult life there. After living in coastal NC for 10 years, I really appreciate the low humidity!

By the way, what took you to AK?

Years ago I worked for Seattle Refrigeration, which was active in the Alaska seafood industry. My first gig was drafting the refrigeration installation for a sophisticated catcher-processor crab boat. That's a story I would like to write someday, because there were amazing personalities and hairy events involved. (Like The Deadliest Catch stuff. My assistant is Sig Hansen's nephew, and he could work on that boat except that his wife won't let him.) I served as chief engineer on the vessel I helped design, and later have worked in several Alaska plants.

When I lived in Prosser, WA, I got involved with a writing group in the Tri-Cities, and my wife and I have friends and family there. Because of the writing thing, I have actually had a minor hand in editing two #1 best-sellers. The sunny climate is nice, and we hope to retire there in several years. Maybe we can meet someday.

1) For someone to send you a private email, you need to register to become a member.

2) Much more detail is required to develop an extraction plan:

• Where do you want to set up this plant?
• What volumes are you after?
• What resources do you have in place now?

I'm sure a lot more info will be required before someone will commit to working on this.

You can send me a private email here.

Mike, ChE