Anyone ever heard of or used Cold Clear it is supposed to allow pretty much anyfeedstock to pass the coldsoak test. I am looking for opinions.

Schroeder launches Cold Clear Filtration system
http://www.biodieselmagazine.c....jsp?article_id=3491
By Nicholas Zeman

Posted May 18, 2009

Every biodiesel producer and distributor must pass the ASTM cold soak filtration test after Oct.1, 2009. Because many biodiesel fuel samples have failed cold soak filtration since its introduction into the fuel quality parameters, Schroeder Industries of Leetsdale, Penn., began to research the problems and develop a solution.

What resulted from Schroeder’s work was the new Cold Clear filtration system said to bring off-spec biodiesel into compliance with ASTM guidelines and improve cold-flow operability. “We spent lots of time in the lab and ran a lot of fuel samples,” said Jonathan Dugan, biofuels product manager for Schroeder Industries. “We checked sterol glucoside and monoglyceride levels among others, and determined it was no single component that caused biodiesel to fail cold soak filtration, but a variety of impurities. In fact, the system brings biodiesel into compliance without changing monoglyceride levels.”

Schroeder tested fuel samples from producers throughout the biodiesel industry and created some of its own methyl esters in order to study the crystallization process said to precede the gelling of biodiesel. Because the company has a patent application to protect Cold Clear, Dugan couldn’t tell Biodiesel Magazine what particular conclusions the company made regarding the relationship of impurities to methyl ester gelling, but could only speak in general terms.

“When you open up the chemical engineering book and start to study the crystallization phenomenon, you see that removing the ‘seeds’ of crystallization is how you stop the process,” Dugan said. “We ran a lot of fuel and crunched a lot of numbers and found certain correlations in the data.”

Cold Clear works by removing certain contaminants “that create higher than normal likelihood of surface crystallization” on filters which can cause break downs. The system is designed to be a single pass three-stage bank of filters and absorbers that sequentially remove those compounds likely to cause filter plugging, Schroeder stated. “I think it’s the easiest equipment on the market to implement into the scheme of a biodiesel plant,” Dugan said. “It’s a simple housing with absorption cartridges that can be changed very easily, and there are no hazardous materials or chemicals involved.”

Each three-stage housing compartment and cartridges can treat an estimated 15,000 gallons of B100 per complete change. The filtration housing is sized for five gallons per minute of flow, but is easily scaled for higher requirements that can accommodate the specific needs of individual plants.

JG
-good post john, NOW what! Tom

I developed a similar process about a year ago when temperatures started dropping below freezing. I'm not in a hurry to produce hundreds of gallons per day so settling rather than filtering was quite adequate to separate the high melt point components from the BD.

This is the simple method I use to make cold compatible BD. Mix a 50:50 blend and keep the barrel outside in the ambient temperature. The components that cause problems will precipitate out and settle to the bottom in the cold. Always use the clear fuel mix from the top of the barrel and problems will be minimized.

JG
-what temps are you refering to, how cold can you go with 50/50 mix without gelling? Would your upflow system work for this? Do you reuse the high temp bio in the summer, or trash it? sorry for all the questions, this is a new subject for me Tom

The 50/50 mix of canola feedstock BD starts to gel at about -25°C, however stuff starts dropping out at 0° to settle on the bottom of the barrel. I'm using a 30 gal settling/storage barrel with a hand pump w/ 5µ output filter. The pump inlet pipe is about 8" off the bottom so the stuff that settles doesn't get sucked up. Even if it did the filter would catch it. When it gets below -25°C I increase the dilution in the barrel to 25/75, and then to 15/85 which is good to about -30°C. I've run a 10% BD mix to -35°C which is about my cut-off temp for running the diesel. The gasser truck is much more compatible with extreme cold running than the diesel unless I'm taking a long trip.

For edible oils the process is called "winterization". The oil (or biodiesel in our case) is cooled to a specific temperature and held there. Big tanks are used, since this is essentially a batch process (Cold Clear seems to have a way to do in in continuous flow). The high melting point fats slowly settle to the bottom. The portion that stays clear on top is sold for salad dressing. The portion that settles to the bottom is currently popular to use for non-hydrogenated fryer grease. It behaves like hydrogenated oil, but isn't.

Diluting it with diesel, as John does, actually helps the high melting point fats to settle easier. This is due to the average lower viscosity. Note that it won't work if there are strong thermal currents stirring up the barrel. The temperature needs to be a little below the melting point of the high melting point fats or esters.

I've had samples from clogged winter filters tested at school (GC-MS). The worst of the clogging material had a melting point close to or slightly over 100c!!! It was completely transesterfied oil, but of very high melting point. It wasn't "bad" biodiesel, or under-reacted, or under-washed. The high melting point fraction was in the feedstock, and was most likely the product of cooking.

There are always some low melting point fractions in any veg oil or biodiesel. The higher the percentage of these low melting point fractions in your particular fuel, the better it will perform in winter.

Cheers,
JohnO

"Winterization" is certainly an apt term, especially for BD fuel blends. It's good you could get some of the filter clogging 'stuff' tested. Your results confirm what I discovered with more primitive melting point analysis. I concluded that it was animal fat BD from whatever was cooked in the fryers. All the fryers use Canadian canola. It seemed odd that the BD would appear as a clear solution at room temperature but once it chilled to below 0°C and the stuff dropped out it required a much higher temperature to melt it. Some of the stuff that settles out in the bottom of the barrel doesn't go back into solution till the heat of the next summer. Thanks for confirming it wasn't just a mistake in my 'non-laboratory' analysis. I'm also wondering if there might be some reaction between the BD and the PD that causes the stuff to drop out of solution and perhaps change it's properties. I'm blending the BD with D1 winter diesel so I know it's not the paraffin wax the refineries add to the summer grade D2. On these cold, near-freezing mornings we're getting now, my samples of straight D2 are all hazy from the paraffin starting to drop out, even though it won't actually start to gel until well below freezing.

The source of the high melting point fats was probably not animal fat, but from cooking. The locations of some of the double bonds were not "natural". The percentage of material trapped in the filter was very small, considering roughly 700 gallons of chilled fuel passed through before it clogged. To clog a filter only rquires enough material to coat the paper material, perhaps an evenly spread tablespoon-full. Even assuming many times as much material passed through before enough collected to stop the flow, say, a pint total, that's less than 0.02% by volume, and likely to pass most quality tests, including ASTM.

I've observed more homebrewers making great efforts to insure fuel quality than the large commercial fuel makers and sellers. The worst of them have attitudes that imply that as long as the fuel meets minimum ASTM specs, it's up to the customer to worry about it. Any quality steps beyond minimum ASTM specs are seen as a waste of money. Since the industry is so marginal anyway, this makes sense from a business standpoint, but not from a market standpoint. Clogged filters in vehicles harm the public image of biodiesel, even if the fuel was "good" per ASTM standards.

Homebrewers tend to obsess about what they're putting into their tanks. They already see all the crap that is potentially in the fuel. We're starting with discusting used cooking oil that is contaminated with food bits, cleaning solutions, trash, rain water, cigarette butts, rust etc. None of that is good for an engine. We add drain cleaner and industrial solvent, which also don't belong in an engine. We drain off soap and glycerin, which also don't belong in engines. We water wash, knowing that water in fuel will harm engines. We dry it, filter it, and store it more carefully than any commercial fuel station. Then we watch the engine for signs of problems and worry about every small noise or hickup.

What does a commercial fuel buyer do? They fill up the tank and drive, oblivious to the fuel until the vehicle stalls along the side of the road. If Cold Clear improves the quality of commercial fuel, then that's a good thing for the commercial image of biodiesel.

BTW, paraffins are a normal constituent of all diesel fuels. They're not "added". The name "Paraffin" refers to particular molecular shape, in this context, not to candle wax. When paraffins condense they form wax, another technical name used in the chemical industry, referrin to the solid material that results from a liquid changing phase to a solid form as temperatures change. The refining process chooses the petroleum fractions that it leaves in diesel, rather than blending various fractions from several separate processes. The exception is the method used to make winterized #2-D. It's a blend of conventional diesel (#2) with #1-D or kerosene (according to my SAE Fuels and Lubricants handbook), intended to lower the cloud and pour points. This is the same approach we take when we mix our biodiesel with #2 diesel. We may fail to realize that the diesel itself may not have been blended for cold weather operation. Whichever liquid starts to recipitate first will initiate filter clogging wax formation in both liquids.
Additives that repute to lower the useful temperatures of diesel fuels do so by suppressing the agglomeration of wax crystals, not by avoiding their formation. When they don't agglomerate, they more easily pass through filters. What Cold Clear may be doing is the opposite - forcing them to agglomerate, so that they do get trapped in filters, but do so before they get into a vehicle fuel tank. Now that's a neat and useful trick.

Cheers,
JohnO

quote:

The source of the high melting point fats was probably not animal fat, but from cooking.

Is this suggesting that the cooking process altered the VO and produced high melting point fats?

I'm thinking that the high melting point fats are from animal parts cooked in the VO.

Perhaps I wasn't clear about paraffin being 'added' to D2. The process of refining crude oil to make diesel fuel and other products extracts paraffin into the D2 output stream but not in the D1 output stream. http://www.chevron.ca/operatio...fining/treatment.asp

quote:

Originally posted by johno:
The source of the high melting point fats was probably not animal fat, but from cooking. The locations of some of the double bonds were not "natural". The percentage of material trapped in the filter was very small, considering roughly 700 gallons of chilled fuel passed through before it clogged. To clog a filter only rquires enough material to coat the paper material, perhaps an evenly spread tablespoon-full. Even assuming many times as much material passed through before enough collected to stop the flow, say, a pint total, that's less than 0.02% by volume, and likely to pass most quality tests, including ASTM.


Cheers,
JohnO

Johno,
Is there any likelyhood that Trans bonds could be broken and CIS bonds created while cooking or vise versa?
How about electoloysis to break the Trans bonds back to carbon double bonds? or something similar?

We use Cold Clear in our commercial plant. The system works as follows. The first housing is a very fine filter. About 3 microns. The second 2 housings hold filters that will actually adsorb the impurities that act as "seeds" durring crystalization.

Learn more at http://www.r3energyllc.com

"Is this suggesting that the cooking process altered the VO and produced high melting point fats?"

Yes. I thought this was commonly known. Sorry to have made the assumption. Just to clarify: cooking doesn't produce fats, but it can convert existing low melting point fats into high melting point fats by the critical location of added double bonds. This is the basis of hydrogenation, which converts something like soy oil into margarine. In a hot pot of oil, with a few wild H2O's floating around, there are opportunities for a few opportunistic hydrogen bonds to form. The longer the exposure, and the higher the temperature, the more likely it will happen. Some bonds are cis-, and some are trans-, which can influence how the fat coalesces and forms crystals that lead to cloudiness. The food industry has gone to great pains to insure the "right" molecules are present in oils that need a nice appearance. Cloudy salad oil doesn't look as appetizing as clear oil.

The used oil we use for making biodiesel isn't salad oil, sad to say.

As far as I know, this is considered part of the oil aging process, but most people worry more about oxidation and polymerization.

Cheers,
JohnO