[Gasification] Fluidyne Update.
Doug.Williams at orcon.net.nz
Fri Dec 2 12:26:02 CST 2011
Hi Gasification Colleagues,
As we are almost to the end of another year, it's timely to bring you the Fluidyne Update on our gasification development programme being conducted in California. Apart from the development programme, there are many other project issues of infrastructure support needed for successful implementation of medium scale industrial gasifiers, so substantial time and resources have been allocated during this past year to researching a match for specific scenarios. The year has passed much to quickly!
Visitor to New Zealand.
A visit on 10th October from my long term friend of the Producer Round Table days, was Ludo Larcross, now living in Thailand for the past 20 years, and heavily involved with biomass energy projects. We spent a few hours talking gasifiers down my back shed, running the Pioneer Class gasifier I have set up, and discussing the prospects of bringing many of our old colleagues together again. All of them represented their countries Institutions or Aid Agencies, and were responsible for initiating many of the gasification studies and projects during 1970's and 80's . I know some will welcome the chance to catch up Ludo, so should drop me an email if you read this posting.
Latest Testing in California.
The test programme for the long awaited MK10 Andes Class gasifier took place from 5th-22nd November, bringing a significant change to how the gas is made. Actually, while the basic work platform of coolers, filters, and condensers of the Andes Class programme was reused, the gasifier itself is new, and of linear design. We refer to it as "Linear One" for a working title.
The MK9 Andes Class round hearth design, was during 2011, pushed to the limit of it's gas making capability, just reaching a wood conversion of 270lbs/hr (120kg/hr) which roughly equates with 1.2 million btu's for process heat, or 100 kWe if generating engine powered electricity. In actual fact, this design was more stable around 75% of this output, but provided a capability to study how the fuel behaves, moving at high bed speeds, within changing parameters to maintain a tar free gas making capability. They
chipped just over 400 tonnes of logs for these test, which puts real meaning into processing a forest through the small 7" funnel of a gasifier throat.
The new linear gasifier is contained in a flat sided casing, with a fuel feeding auger sticking out of it's rear, heated to around 300C by the exiting gas. This lower output gas temperature has already made redundant the primary gas cooler of the Andes componentry, allowing for a more compact and versatility of assembly options. The feed auger connects to the existing fuel locks and drier/elevator system, and the two gas outlets plug into the Andes component platform with flexibles. This will be easier to understand when I post the project photos on the Fluidyne Archive, which is now back at it's old site www.fluidynenz.250x.com These will be available in about a week or so.
Due to the size of the existing gas cooling/cleaning system, the output from the new gas making hearth was made for the same 1.2 million btu gas production, but with such changed parameters, felt quite nervous as to how this design would perform. As it turned out, the output increased by 6%, waste char reduced to about 2% (down from 4%) and the gas quality only slightly fluctuated right through the range of flows tested. These were measured at 100, 108, 124,147,155, scft/minute. At maximum output, we saw CO 26%, H2 15%, and CO2 11%, but CH4 readings were found to be faulty due to a problem of the sensor calibration. The analyser is to be returned to the manufacturer and reset specifically for CH4, and a second unit ordered as a back-up for the 2012 continuously operating test programme beginning in February, when the heating system is required.
After the first successful test run, an inspection was made of the internal metal and refractory, looking for any distortion to the components, as the oxidation temperatures were higher than previously experienced during this development programme, measured at 1,350C in a safe TC position just out of the oxidation lobes. As almost the whole system is automated, the gasifier was restarted for a continuous 24hr test for the second run, but manual draining of the aqueous condensate was required about every six hours. This amounted to roughly 10 gallons (40 litres) each drain, an increase over previous tests, highlighting how climatic seasonal conditions influence and change a gasifiers performance. It takes no imagination to see how this much water would affect the engine or burner performance, if not removed from the gas stream.
Although set-up in February 2011, the large Cyclomix burner assembly and heat exchanger had not been used for last Winters heating trial, due to other business demands for the time available, but was ready for use for this latest test programme. A refractory felt lining was installed into the combustion chamber, and a pile of refractory brick mounded in front of the blue flame, creating an incandescent radiating mass. It can be said now, that with the gas making quality stabilized, very accurate emission tests could be conducted on the flue gas. All these tests were conducted by Tom Miles, who has patiently waited in the wings for us to bring it all together, and see if we could meet those standards he measures. His written report hasn't reached me yet, but he was pleased at the outcomes, and looking forward to measuring the Tecogen CHP system in 2012 on the new gasifier.
>From a personal perspective, these latest trials were in my opinion, some of the best producer gas that I have ever seen during the 35 years of working with this gas. Two years ago, it was established that in this location, producer gas could replace LPG for around 60% cost wise. LPG costs this past year are up 50% over last year, so the economics are swinging well over into credits for producer gas. As a project initiated to replace LPG, bringing stability to the heating costs for this Forestry Nursery, it is very satisfying to see a project reach it's objectives. This coming year of 2012 is when it all comes together, so for us all involved, it's "steady as she goes" !!
Automated engine gas control.
Trials with the Tecogen on producer gas were put on hold, until I returned for these latest tests. Using the old Onan generator, we had to develop an automated starting sequence of gas mixture control, requiring a rather unusual fabricated assembly. Not quite a mixer, but a signal generator for the gas regulating supply valve. After a few false starts to get the programming right, the engine was able to start-up and run quite smoothly. Time ran out for me to swap the system over to the Tecogen, but they assured me it would be fitted in time for the February trials.
Finally, the large IHC engine used for the Laimet Chipper threw a con rod, just a few days before I left on 22nd November. A replacement engine has been located, and in the fullness of time, be built into a new transportable trailerized assembly. In the mean time, testing has commenced on using a wide range of standard wood chips available from local contractors. The new linear hearth is fully and easily adjusted, so these tests will be to establish a clear boundary for fuel quality. Having had a chance to see these chips, it is clear that quality control is not a factor for many of these suppliers, and fines make up a large proportion of these piles.
Hope this has been of interest for you.
I take this opportunity to wish you all an enjoyable Festive Season.
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