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Patio29Dadio

Dewatering Self Dumping Hopper Fail

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Turns out that a dewatering hopper is not a good choice for dewatering grain stillage.  Good news is that I have other uses for the hopper.  Bad news is that I have to come up with another process.... one that is likely to require another piece of expensive equipment.   Either that or need to find that pig rancher quickly! Sigh.

Interesting in what others are doing here. 

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Ask some local breweries what they do.  I found an environmental group that takes them.

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Are there any craft guys that use dewatering screws that process less than 10,000lbs of grain a week?

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What about this idea?

A lautering mash tun with a rake and plow used as a dewatering device for ongrain stillage? 

I envision a process where the rake and plow clear the screen well enough to allow water to drain enough that the remaining material in the tank can be shoveled out.   This is confirmed a bit by our manual process of using a hard-rubber squeegee on the screens of our dewatering hopper noting significant increase in water flow drainage from the bottom of the hopper. 

The benefit of this type of process being supported by the mash tun with the rake and plow is that it does not require manual labor to squeegee, and we would have a mash tun for malt whiskey production. 

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So the way we are getting this process to work for is... use the hard rubber squeegee to keep the screens clear.  We just hit it a few times every five or ten minutes for a couple of hours while we are doing other work around the distillery.  Now we have a nice semi-dry grain bed from the stillage that will dry some more over night.  Then we can shovel it into a bin.  The process is too labor intensive when we scale up production in the future, but for now it works.  I can get ranchers to take this stuff as still wet stillage without having to go through all the FDA hoops for real dried distillers grain feed. 

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We've thrown in the towel on handling wet distillers grain and have now ordered a centrifugal  dewatering machine. Trying different methods has been a waste of time. Trying to find a reliable farmer to take liquid has been a huge frustration. We want to expand into new markets, and having a true solution to dewatering is the only way to do it.

It makes me queasy knowing how much I'm spending just to make it easier to get rid of my waste.

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When we started we used a hydro seive worked like a dream . Basically fool proof set up . Since then we have changed to grain in fermentation and stripping using steam injection . Now when it's time to dump stripping still we pump the slurry into a honey wagon and out to the pigs it goes . Any extra that pigs don't need is sprayed on the land as fertilizer and worked in . 

So imo if you can't sell it to a hog farmer sell it as liquid fertilizer . 

If I was going to make a dewater system I would use the air tubes from a airation grain bin . They are 28 inch around and 3 feet long .If set on an incline and turned like a cement mixer.slurry can be pumped into top ,liquid drains thru and the tumble action keepsscreen clear . As it rolls dry material works it's way down and tumbles out bottom of tube . By adjusting the feed rate , the rotation speed , and the rate of incline you should be able to get ur spent grain as dry or wet as you want . 

Airation tubes are available In galvanized steel ,aluminum,or stainless steel . At this stage in production there no need for stainless . 

Tim

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Skaalvenn. 

Can you let us know how the centrifugal system works out. I’m interested in something similar. 

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1 hour ago, thomasd said:

Skaalvenn. 

Can you let us know how the centrifugal system works out. I’m interested in something similar. 

Will do. It's not scheduled to arrive for about a month.

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I have done a lot of experimenting with de-watering over the last 10 years. 

With a high % of malted barley at a large size grist, a simple lauter screen like most brewers use is the best option.

Hammermilled rye or oats (and I assume corn which I have never done) a simple static screen just blocks.

Another trial with a bladder press which forces the liquid through a filter screen was useless. The pressure just pressed the solids into a hard cake on the screen and totally blocked it very quickly.

The cheapest option I have found is this Vibroscreen. Cost me less than US$3,000 out of China. I am sure the ones made in US and Australia by Kason would be much better made but more $$$

For basic de-watering this worked very well with no clogging issues. I was using it to remove the solids before fermentation but I found the solids were still too wet and I was losing too much sugar. I am now using a simplified belt press. 

The vibroscreen has less solids in the liquid than the belt press, but the belt press produces drier solids.

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Video of my Australian made v-belt press which works very well.

Cost me about US$7,000

Cake is much drier,  liquid has more fine solids than the vibroscreen but my direct fired still can just handle it without burning.

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We do anywhere from 1000 to 3000 pounds of hammer milled corn/rye and roller milled wheat/barley a week using a half a large (36") rotomold tank with a #6 stainless mesh screen and a squeegee.

Our liquid is not completely devoid of solids, but the resulting liquid is reasonably cleared, and the resulting solids are reasonably dry.

500 gallons of wash that contained 1000 pounds of grain will fill 8 20-30 gallon lock ring barrels (or about 3 55g lock top drums) - just to give you an idea of the overall solids capture and overall volume reduction post distillation/separation.

Screening in this fashion, it is critical that the stillage be very hot.  Once the stillage falls below 100F, the viscosity makes it nearly impossible to screen with this method.  You may need to add cold water to the outflow to reduce the temperature to meet your discharge reqs.

The squeegee and it's operator are a critical part of this operation.  The screen will blind very quickly otherwise.

It takes about 20 minutes to separate a 1000l batch (~265g/~500lb).

Roller milling the barley helps keep enough husk in the mash to aid separation post distillation, but this is not entirely necessary.  Our rye is 100% hammer milled rye and will separate pretty well without massive solids bleed through.  The husk from whole oats is awesome in this regard as well.

We've been considering ponying up the $15-20k for an asian-sourced separator unit, screw press or centrifugal screener - but considering the effectiveness of this very, very, low tech approach, it's a tough decision.  I don't think a machine will end up saving any time over this process, since the clean up will likely take the same time.  However, it would make things much easier, as the separation process is hot, steamy, wet, messy.  We do it over our floor drain area, which makes clean up relatively painless.  Trying to do it without the ability to wash down floors, good luck.

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7 hours ago, Silk City Distillers said:

We do anywhere from 1000 to 3000 pounds of hammer milled corn/rye and roller milled wheat/barley a week using a half a large (36") rotomold tank with a #6 stainless mesh screen and a squeegee.

Silk, any chance of a 15 second video

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6 hours ago, Patio29Dadio said:

It is amazing how simple adjustments can salvage an otherwise failed solution.  Just slowing down the pump and spreading out the discharge over a wider area and we are dewatering without much trouble.

https://youtu.be/Ap969PXSqfc

If you don't mind me asking, what size is the hopper and approximately how much did it cost?  Looks like a good solution...

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6 hours ago, mheisz said:

If you don't mind me asking, what size is the hopper and approximately how much did it cost?  Looks like a good solution...

3 cubic yards and about $9k new with freight.  That should handle up to a 700 gallon batch.  It is a self-dumping hopper.  We allow the grain to drain overnight and then take it out back to dump it into bins or a trailer that we will eventually use to have picked up or take to ranches for animal feed, but for now take it to the dump compost area.   If I had a farm, I would just make a big compost pile on my land. 

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On 7/11/2019 at 11:15 PM, Hudson bay distillers said:

Pete are all 3 rollers pressing the spent grain equally or is the second and third set progressively more pressure than the one before .

Tim

Roller pressure applied by belt tension only, no opposing roller. Too much pressure would push too much solids through filter belt. Most belt presses have belt running between pairs of press rollers and as you say the pressure increases with each set. 

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