Producing electricity and drying heat

[Cvanmilligen]

A wood products plant in west TN is installing a modest sized gasifier to produce heat for their kiln as well as about 110 kW of electricity from waste sawdust and chips.  We designed and built the unit to suit their needs. It could just as well have been designed to power a sawmill directly by powering an engine or a generator using the gases boiled off of the wood fuel.

Why only get heat when you can get electricity for not much more?

Neal Van Milligen
Bioten Power and Energy Group
cavm@aol.com

[Fla._Deadheader]

 OK. Where's the pics 

  We need photo tutorials around here, to understand what's being said. 

  Welcome to the Forum. 

[moonhill]

Yes, please share more.  Do you have a wed site to view?  What is the smallest unit you deal with?  Or are they all industrial size?  How is the electricity produced, Sterling  engine? 

I just reread you post Neal, and saw you are using gasification to run a generator?

Tim

[Cvanmilligen]

This is the video our fabricators put together on the 250 kW gasifier they build for us. It will introduce gasification to you.  The illustrated unit will consume about 2.25 lb of 25% moisture content woody fuel per kW out put per hour. So this size unit will consume about 560 lb per hour.  

The fuel is heated inside the unit to boil off the volatile gases which are cleaned and cooled before being directed to an engine. The gaseous fuel (syn gas) replaces gasoline, propane and natural gas in engines.  It can also replace about 90% of the diesel fuel used in an engine.

Substantial heat is available from the gasifier itself, the gas cooling system and any engine using the syn gas as fuel. If no engine is being powered the syn gas can be used for heat by itself.  A unit this size will generate about 4,000,000 BTU per hour in useful heat.

There are many gasifier designs available from a wide variety of developers. Several are posted on the internet and You Tube.  I imagine you will be able to find one or more to suit you needs from a company with which you will feel comfortable doing business.

Neal Van Milligen
cavm@aol.com

[pineywoods]

Verrry interesting. Is the filter just a dust cyclone or is there further filtering? The clean burning flame would indicate that the syngas is quite clean. Where in the gas stream is the blower located, ie are you pressureizing the combustion chamber or pulling a vacuum to extract the syngas? Would this design scale down somewhat, maybe small enough to run a 20 hp engine driven welder/generator? The video is very nicely done..

[Cvanmilligen]

Thank you for your kind words.   The fan is only used to pull a slight vacuum on the system.  When an engine is used for the syn gas it provides the vacuum.

The large white cylindrical filter is a concept filter since so far we can use a simple box of wood chips to exclude ash from the gas.  We provide virtually no tar and do not even have a tar filter.  You will find similar products offered by a variety of fab shops and designers.

Usually a fabricator can produce units in sizes from 10kW to about 2MW.  Beyond that an engineered design change is necessary.  The system can be manual or automatic as desired.  As you can imagine, there is a wide range of specs and costs among different commercial providers.  However, this is an old technology and can be found demonstrated in many odd corners of the world. We even found a farm in Alabama which has been powered by syn gas since WWII.  They even use an old Willies Jeep motor for their generator.

Regards,

Neal Van Milligen

[Tug Hill Walt]

is there any way to scale this technology down to the size of an e- classic?  It seems that we should be a way to use the excess energy produced by our small scale bio-fuel heating systems.  (bio-fuel is more PC than wood burner)

[Cvanmilligen]

Walt tell me more of what you have in mind. I thought the e-classic was a wood burning furnace.  Do you mean you want a gasifier that is about that size?  Or do you want to use the heat from your furnace to produce electric power?  Or have I missed it altogether?

Neal Van Milligen
cavm@aol.com

[JSNH]

A dream would be making 500 to 1500 watts of 48 volt dc off the 175-185 degree F hot water on my outdoor boiler. Something even 20% efficent would be good. I have so much waste wood to dispose of and a grid interactive power system.

[Cvanmilligen]

What you are dreaming about is called an ORC or Organic Rankin Cycle system. It takes heat from whatever source and converts it into electricity and even air conditioning cooling. The system works by taking a sealed container of liquid which can be water, lithium bromide, ammonia, propane or certain others.  The container is heated anyway you choose.

The heated liquid expands and shoots up through a tube which contains a micro-turbine.  This spins the turbine and makes modest to fair amounts of electricity via a small gen head.  It can be AC or DC.

The heated liquid then moves to a larger vessel which allows it to expand and thereby cool itself. Usually this expanded vessel is located in a tub of water which will become very cold or even freeze without effort on your part. Alternatively the expansion chamber can be located by a fan which will air condition an area for you.

The now cooled liquid is attracted back to the heating container by various means. Often this is accomplished without the expenditure of energy by taking advantage of the properties of the particular liquid.

Any competent mechanical engineer could fabricate a unit of sorts for you.  Commercial units are tough to find at economical costs. I have no doubt that the fabrication engineers I have worked with could do it in a snap if asked.

Does this answer your needs?

Neal Van Milligen
New Range Power Corp
cavm@aol.com

[Tug Hill Walt]

Neal, about the same physical size as an E-classic. But my thought was to possibly use some of the smoke and gasses from the exhaust al-la the WWII charcoal burner cars. I'd also like to use the excess heat going up the stack.

[Tug Hill Walt]

I just got to thinking, you are describing a big propane refrigerator. Only there is a turbine in the expansion tube.  I wonder how a freon product would work as a heat transfer medium.  I think I need to work on this further.

[JSNH]

Yes Neil an ORC or Organic Rankin Cycle generator is what would work well. What is needed is a company to mass produce a small one for off grid/ grid interactive people like me. They would sell even at $3,000 or even more for a 1-2kw unit. I see some companies that are developing units but they talk small units but after r&d they go for the large units. A company that looked good was www.energrotors.com they had some small concept units and were looking at selling small ones but it appears they turned away from the small units.

JSNH

[Cvanmilligen]

Walt you are correct. The charcoal power units used all over the world during WWII were the precursors to today's down draft gasification systems. The video referred to my earlier post is such a gasifier. It produces a clean gas which is essentially low grade propane and can be used whenever propane or natural gas was used.

JSNH an ORC would suit your needs very well.  What size electrical output do you envision as most appropriate? As Walt said, propane can be the working fluid.

Neal Van Milligen
cavm@aol.com

[JSNH]

For myself something that would run off 175-185 degree hot water using between 20000-50000 BTU for 1-3kw output would be ideal. That would be based on 20% efficient.
JSNH

[Cvanmilligen]

Such a unit could be produced but the cost of a single system might be unreasonable. It would have to become an inventory item and mass produced. For that there has to be a market.

Neal
cavm@aol.com

[Tug Hill Walt]

OK so how about a forum poll.
If such a unit was available for around $3000 dollars, +/-  who would be interested.

[Dana]

Concerning the poll... Is 1 to 3 kw enough? I would think 12kw would be closer to what a typical home or small farm would require.

[Bart May]

Great discussion Neal and company!. I would buy a Organic 3kw Rankine Cycle system for $3K! I have tried figure out how to produce electricity or AC from 180 degree water for some time now. I have read much about Gasification. My outdoor wood boiler paid for itself in 22months. My old home is easy to cool but a real bitch to heat. I found a 10 ton lithium bromide chiller run around $30K. Bart/VA

[woodbowl]

Years ago a friend of mine had a lot of broken mirrors and attempted to aim the suns rays onto some old boards. There must have been 30 to 50 hat sized mirrors wedged into the ground facing the boards. The sun was not very cooporative that day and kept going in and out of the clouds. After some time he gave up and walked away to do something else. The next day, a bright sunny day I might add, he came home to find the boards burned up. It was concluded that about the same time of day on the next day, the event was successful.

It takes heat from whatever source and converts it into electricity and even air conditioning cooling.

The possibilities are endless.

[Bioman]

The acronym is CHP (combined heat & power).   You could add a C to that and make it CHPC if you added cooling to the package.

We've been working on this project (like so many others are) off and on for about 8 years.  From all the feedback we've gotten over that period of time we feel a system that would generate a minimum of 2KW is a size that would be marketable and fit the BTU ratings of most domestic OWB's.  Of course something closer to 5KW would be nice, but with batteries and inverters, 2KW would meet the needs of most of us if we were conservative.

We spend a lot of time and money on Stirling technology - couldn't make it viable.  There are too many limitions on material properties to make this possible today.  There are still a lot people dumping money into this technology though, so maybe someone will make a breakthrough.

As posted previously the ORC appears to be the technology most are pursuing today (ex. http://www.powerverdesolar.com/technology.php) .  Again the problem is cost.  Some of our testing was done using a scroll compressor from an airconditioner (made by the millions so cost really isn't that high).  The problem is the pumps, condensors, controls etc, and a reliable heat source that produces BTU's at a cost that will overcome the inefficiency inherent to the design. 

To those who are curious, there was a previous reference to an expensive water fired single effect absorption chiller that cost 20-30K.  Here's a link to one such unit and a diagram to go with it.  http://www.yazakienergy.com/waterfired.htm

So, what we are all waiting for is someone to package a versatile biomass boiler, some kind of ORC generator for power (or some other technology), and a water chiller for air conditioning at a reasonable price.  Kinda the holy grail of energy in my book.......but I think it is coming sooner than later. 

[JSNH]

It looks like some one in Australia is getting close to making electricty from low temps.

http://www.cogenmicro.com/index.php?select=167