Experience with EPS + ozone generator

roasting & roastery operations

Experience with EPS + ozone generator

Postby Yara Tucek on Sat Nov 20, 2010 8:25 am

Before we purchased our roaster (UG22) I was trying to find some information about people using electrostatic precipitators and ozone generators to deal with smoke and odor. There are some interesting posts here on coffeed from Paul Pratt and others (http://bit.ly/9ZeHxZ and http://bit.ly/bG1wer). I also exchanged few emails with Mark from 7 seeds who seems to have similar set up.

I would like to post our experience with this system and perhaps get some answers on topics we are still dealing with.

Our system:
Probat UG 22 (1958)
2 x Electrostatic Filter boxes (4 individual cells)
1 x Ozone Generator O3 Technology - pumps ozone to the tubing approx. 70 cm in front of EP
Ventilation system to cool down air in front of EP filters (measured at 50-70°C)

What we think:
- the EP filters decrease the visual smoke by approx 70%, during roast, smoke is almost invisible, FC creates a slightly visible smoke ... we dont roast through SC
- we clean the filters usually after 1000-1500 kg of roasted coffee, I would like to find out the ideal chemical solution to do this, any ideas? We currently use only water ... (manual says use "cleaning agent")
- there is A LOT of accumulated compounds AFTER the EP filters in the chimney, this really surprised us and we have never seen this before
- we are a bit skeptical about the advantage of Ozone Generator, we do not have means to measure the odor and although the producer claims 90% of odor removal, we estimate a bit over 50% - it would be interesting to compare with other roaster using this system and the actual placement of the ozone injecting tube

I will try to post some pics of our set up once I get back to the roastery ... any comments are greatly appreciated!

Yara
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Re: Experience with EPS + ozone generator

Postby CuthBland on Tue Feb 15, 2011 6:14 am

We're about to get an electrostatic filter for our Probat L12 - no ozone generator.
Our neighbours will be able to give us an accurate assessment of how much (if any) of the odor and smoke are reduced.
Will keep you posted.
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Re: Experience with EPS + ozone generator

Postby phaelon56 on Tue Feb 15, 2011 7:03 am

I've heard of people using SimpleGreen to clean the filters.

http://industrial.simplegreen.com/ind_p ... urpose.php

In theory you can wash the effluent down the drain but I'd be inclined to make sure it went into a drain that had an in-line grease trap along the way.
Owen O'Neill
Syracuse NY

Phaelon Coffee
and
New York Central Coffee Roasters
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Re: Experience with EPS + ozone generator

Postby nick on Tue Feb 15, 2011 8:16 am

Yara... this is a few months old. How did things end up?

EP: I've seen an EP work best when placed after a water-scrubber. With an electrostatic precipitator, just adding another machine on down the exhaust would, at least theoretically, work best.

Ozone generator: I've done some research about those things after I saw some in use in Korea. There's always going to be the environmental/health question regarding radical O3 molecules being sent out there. That said, it would make MUCH more sense to have O3 added after the EP, not before. The ozone is supposed to quickly oxidize the smelly molecules, so it would make sense that it would bind with a lot of the particulate-matter that's just going to be captured by the EP. When you wrote "in front of the EP," did you mean before or after it in the system?
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Re: Experience with EPS + ozone generator

Postby Yara Tucek on Wed Feb 16, 2011 6:05 am

Owen, thanks for the suggestion ...

Nick, this sounds very interesting. I have to say we only followed the manufacturer instructions for installing and positioning the ozone + ep. What you are saying regarding the position of O3 makes total sense and I will definitely try it. I have no experience with wet scrubbers, will have to look into it ...

This is our current system. You can see where the ozone is being currently injected. Its approx 70 cm before the EP.

ep1.jpg

ep2.jpg
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Re: Experience with EPS + ozone generator

Postby nick on Wed Feb 16, 2011 10:00 am

Yara, here's a water-scrubber I saw built-in to a cyclone/chaff-collector in Korea.
Image
At the bottom right, you see a pump that sends pressurized water to three spray heads at the top of the cyclone. That captures a lot of the particulate matter which gets filtered through that very low-tech fabric filter below, along with the chaff (yes, wet chaff!).

I also recently saw a setup that had TWO cyclones, with the first collecting the chaff the traditional way, and the second containing the water-scrubber.

Also, here's a photo I took in Korea back in early 2010.
Image
Those blue boxes on the left are electrostatic precipitators, while on the right is their ozone generator. You can see that the exhaust is split into three, running parallel, before being combined with the ozone product (no water scrubber in this setup). To be honest, their exhaust ducting was pretty crazy in general, but they say their exhaust is fairly clean.

For those reading who aren't familiar with some of these things:
An EP or electrostatic precipitator, is simply a "smoke eater," which has the exhaust travel into a box with metal plates that are electrically charged. The particulate-matter (which makes up the "smoke" of the exhaust) is attracted to the charged plates and sticks to it like a magnet. Machines like that are fairly common in certain bars and clubs to eliminate tobacco smoke. However, while it can help capture a lot of the solid particles, it cannot eliminate odors.

That's where the ozone generator comes in. Ozone is O3, while 'normal' oxygen is O2. The ozone generator machines create O3 that is mixed into the exhaust. O3 does not want to be O3 in our part of the atmosphere... it wants to be O2, so it wants to get rid of that extra oxygen atom. So that oxygen atom attaches itself to the gaseous molecules that contribute to odors, changing the molecular structure into something that has no odor, or is at least much less smelly. So basically, if O2 can oxidize, O3 is a super-oxidizer.

I did a bunch of research on ozone generators when I saw the setup above back last March. Yes, they can work fairly well, if the setup is designed well. The problem is that ozone is good for the stratosphere, but potentially bad in our troposphere (where we live). The problem is that the super-oxidization properties of O3 make it dangerous for us life-forms. Interestingly, ozone generators are not illegal in the US, but probably only because they haven't attracted enough attention to become scary.
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Re: Experience with EPS + ozone generator

Postby paul_pratt on Thu Feb 24, 2011 5:37 pm

I recently visited a friend who installed the newest version from the company I worked with to build the first. He is running 3 roasters, a 2kg, a 10kg and a 15kg. He did not install a water scrubber just running 2 or 3 back to back ESP cells. Abosultely flawless, just a sweet toasty smell and you would only notice the smoke if you go well into 2nd, and only for a few seconds after you dump the beans into the cooling bin.

The man I worked with now has changed his cell design and it is so much more efficient than the one I was using several years ago, and back then I was mightily impressed.

It now seems to be the opinion that the scrubber is not required for smaller roasters, at least my friend has not complained to me about it anyway.
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Re: Experience with EPS + ozone generator

Postby Yara Tucek on Mon Apr 04, 2011 11:05 pm

Just to update on our situation. After talking with the manufacturer of our ozone generator, we found out, that the machine does not produce enough ozone per hour for the size of our roaster. These are the recommended amounts according to O3 Technology:

7 kg - 20 gram of ozone
15 kg - 40 gram of ozone
25 kg - 60 gram of ozone

I wish we were informed about this by the manufacturer of our roaster before making the investment. Oh well ... We will proceed with exchanging the machine for the bigger one and hopefully will get better results with eliminating the odor around our roastery.
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Re: Experience with EPS + ozone generator

Postby Vajra Rich on Sat Sep 10, 2011 5:46 am

Yara,

Did you switch the inlet for the Ozone to enter after the EP's? If so did you find it changed the effect?

Vajra
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Re: Experience with EPS + ozone generator

Postby Yara Tucek on Sun Sep 11, 2011 11:44 am

Hi Vajra,

yes we did and it didnt work very well. The reason is the ozone needs some reaction time to eliminate the odor ... I think Jan from O3 mentioned something like 2-3 sec. Since our stack is only 10 m high the reaction time was too low. We currently have the ozone inlet just before the EPs ...

Y.
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Re: Experience with EPS + ozone generator

Postby Vajra Rich on Sun Apr 15, 2012 12:05 pm

Hello again,

Im about to undertake installing a system with a fine mist of water, potentially some ultraviolet light and a series of ESP's. I'll report on my experience when something seems worth posting here.

I know this will knock down the particulates but I'm not convinced that the reduction of the aroma will be that significant.

Wish me luck.

Vajra
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