you set-up a timetable for the development programme of a gasified
application, the main activity is just getting appropriate components
built and assembled in the right order. For this project at CalForest
Nurseries, the main application was to replace LPG to heat the eight
acres of Greenhouses, and also to be able to generate electricity with
a CHP engine generator, both for the Nursery, and into the local grid.
Naturally all the waste heat from the generation system is collected
via water, and then reticulated into the Greenhouse closest to the
engine. Waste heat from the gasifier, is eventually, all to go to the
fuel dryer, so that wet, or partially dried fuel can be delivered to
the fuel lock of the gasifier within a specified moisture range.
Now into year three of this five year project, this last year of 2010, has been spent on the intensive study of how the packed bed changes when alterations are made to the dimensional parameters. This required a daily morning strip down of the gasifier which took 20 minutes, then a two hour bed analysis, photos, and discussion with me via SKYPE, down in New Zealand. Any parameter changes were then completed and the gasifier prepared for a 3-4 hour test run in the afternoon, with all data including gas analysis collected and sent to me the same day. Another couple of hours to interpret the results and write up what we might see next day, sees a repeat of the process next morning. We did this for 72 recorded runs, and quite a few that were off the record, collecting over 1,100 bed photographs, and learnt what that we felt we did not know, in our type of downdraft gasification.
1. Wood has an amazing capability to turn into charcoal in 30 seconds over a distance of one inch (25mm).
2. Packed carbon beds of almost any density can make producer gas of reasonable CO and H2 content.
3. Not all uncracked hydrocarbons will carbonize on the engine valve stems.
The cost in time, money, and effort by the on-site team to acquire this information, has been considerable, and combined with making the next components of the total system, required a commitment that few companies are prepared to make. All this just to be sure that our November/December 2010 test programme of the whole system could be "just" evaluated against the promise, of gasification meeting the challenge to replacing fossil fuel.
With our basic Andes Class hearth module now assembled into the Mk 8/9 assembly of primary heat exchanger, ceramic filters, condenser and gas cooler, the new purpose built fuel elevator /dryer was tested for the first time. The 1.4 million BTU Cyclomix burner emission tested, and fitted to it's purpose built heat exchanger, then concept tested.
But the Tecogen CHP engine generator now grid connected, set-up with hot water heat recovery into a greenhouse running on LPG, ready for conversion to producer gas, created our greatest challenge. How do you put producer gas into an engine with a complex emission control system that shuts the engine down at the slightest tweak?
very carefully to at least prove it can deliver the derated 41 kWe
output on producer gas. Normally on LPG, the output is 70 kWe. A
dual gas system is being considered to simplify the conversion, at
least in this testing situation. The Tecogen is a fantastic CHP package
and more time will see it on- line next year.
Nobody can organize the weather however, so in snow, ice, rain, and cold, we worked 14 x 11 hour days back to back to get the test programme completed for 2010. It was fine before I arrived, and it fined up after I left, but the testing under such adverse conditions out in the open air, provided a splendid opportunity to demonstrate just how much waste heat can be collected. This is a double edged sword really, because in warmer climates, this is heat that needs to disposed of if you are using cold gas only.
While our gasifier has endured many changes making it ugly to the eye, it has had the indignity of being considered expensive scrap metal if it did not deliver the desired results each, and every step of this development programme. Our test programme came through with a positive outcome for 2010, and 2011 will see an all new Mk10 Andes Class gas making hearth module built into a new assembly of components to test before releasing to the commercial market.
Another 590 photos were added to the records of this 14 day test programme, and a few show how much work is required to mount these development projects. For those seeking commercially developed gasifiers, who have to put their plans on hold until this, and other gasification technologies mature, be aware. There are a few "companies" out there making unsubstantiated promises, with no demonstrated development programme to support their claims. Your $$ vanish in an instant, but we as an emerging commercial industry, have to carry the stigma of badly researched, and failed gasification projects.
Finally to end this visit, an invitation was extended to me to visit the Woodlands Biomass Centre in Woodlands, California, being operated by West Biofuels, in association with UC Davis, and the Californian Energy Commission. As the facility was not operating, we had the chance to just talk about our technologies, and the issues we had to deal with, just to do what we do in an over regulated society. (and a few commonly shared technical teasers). My thanks to Matt Summers, Director of Operations (WB), Ghasem Edalati, Project Manager (CEC), Rizaldo Aldas,CEC Specialist (CEC, and Dr Rinhard Seiser, (UCD), for your hospitality and informative visit.
The following photos show the changes and additions to the project. Not all is explained or show, but conventional historical gasification is being pushed beyond all the known boundaries written about in literature during this project. This alone dictates to our development team as to what comes next, and be incorporated in the MK 10 Andes Series of gasifiers. The next report of this project will see if we deliver the expected results.
|This is CalForest Nurseries located in Scott Valley near the Oregon border. With it's first dressing of Winter snow, I had a shock to the system after leaving the early Summer heat of New Zealand.|
|Working out in the open is a reality for many projects in the development phase, and the weather turned on it's whole range of coldness for the time I was on site. Things only improved when the gasifier was operating and waste heat radiated out of all components, emphasising the value of waste heat utilisation in colder climates.|
|In this Mk 8 version of the Andes Class gasifier, the gas cooling and condenser modules have been separated from the filter housing, and mounted as an inline assembly. The fuel elevator dryer is much larger than this system needs, but allows the concept design to be tested in preparation for the 2011 development programme. The recycled forage wagon bulk bin, is only to facilitate the fuel supply in this temporary configuration.|
|A view of one hot air duct from the primary gas cooler to the new elevator fuel drier. A second duct will add all the other waste heat from the gas condenser, and final gasifier casing.|
|Difficult to show in the cramped space of this temporary installation site, the elevated tailored feed wagon bulk fuel bin feeds the custom designed fuel elevator dryer.|
|Under the hood cover, the drying chips can be seen inching their way up
the elevator dryer. When fully utilising the gasifiers waste heat, wet
chips can be handled and delivered to the top fuel lock at - 15%
|Shown during emission testing runs, the 1.4 million BTU Cyclomix burner finally was OK'd to assemble into the most important component, and end use of the gas from this project, the glass house heat exchanger.|
|Set now horizontally, the 1.4 million BTU Cyclomix burner is finally fitted to the purpose built glass house heat exchanger. Refractory is to be fitted to the combustion chamber under the exchanger, and heat protective cladding before final installation and Winter trials.|
|The exit side to the heat exchanger.|
|In this view of the burning gas inside the Cyclomix burner, the blue flame of CO and H2 combusting, has little radiant heat, and needs to impinge of refractory to maximize it's heating properties.|
|This front end view of the Tecogen CHP engine generator, shows the nicely built in, hot water circulation system. The magic control system is in the box panels, with nothing to see but circuit boards. I did note that many of the electrical and gas controller parts were of German manufacture|
|Very little to see under the bonnet of the Tecogen, other than the Producer gas connection to the engine via the black flexible pipe, and the silver clad catalytic converter of the exhaust .|
|Inside the greenhouse, this simple distribution manifold supplies the hot water to the heat exchangers through rubber hoses. This is all set up in the easiest way, so that the design can be evaluated and changes facilitated with minimum fuss.|
|Close-up of the copper hot water heat exchangers.|
|Along the back wall, you can see the recirculating air blower fed plenum pipe with hot water heat exchangers mounted along the top in three places.|
|Waiting for the Tecogen to heat up. Tom Jopson ponders the clouds of steam exiting the cold exhaust. This is with LPG as fuel, and although invisible later, the water vapour remains in the exhaust gas just the same. The white temporary producer gas pipes can be seen behind Tom, feeding the mixer to the engine manifold under suction, and the smaller pipe, pressure feeding the control valve.|
|This older model excavator was obtained to make the log chipping easier, and will be fitted with a fully controllable log grab.|
|Just arrived on site during my visit, this is the new log grab to be fitted to the recycled excavator.|
This is the 600 ton log storage pile held at the Fort Jones Nursery of CalForest, for the Winter fuel supply for the Andes Class gasifier.
|An invitation to visit the Woodland Biomass Centre, operated by West
Biofuels in California provided the opportunity to see how much effort
is going into developing large commercial gasifiers. This recirculating
fluidized bed has two scrubber towers standing behind the red tanks,
the twin tube gasifier, then the filter bag house.
I forgot to photograph the engine outside, due to lots of interesting discussion.
|Locked safely into it's earthquake proof framing, a clear view can be seen of the recirculating ducts between the gasifier and it's combustor module.|