If gasification is such a great technology; then why hasn't it caught on yet and why hasn't it become more mainstream?
Well here is the deal, deep down this is the question many are asking themselves when looking into this technology. This fuels skepticism and with current information on the subject available today: This just leads to more skepticism and creates misconceptions that are
no longer relevant to most commercially available
modern systems of today.
If you were to look into the history of gasification you would find this is a very old technology. Most then, are probably thinking "well this must not work, there must be issues that can not be overcome. Otherwise it would be here now! " You then dig a little deeper to find out more and why this is. In WWII gasification was widely implemented in Europe, to fuel cars, trucks, power generators, farm equipment and even military vehicles. Gasifier plants were even commercially available at this time and even in this time of history they were very expensive of around $3000.00. These systems had zero automation and were completely manually operated by the end user.
When the user would open the hopper lid for refueling and depending on fuel level; they would be met with a massive plume of smoke; exposing the user to carbon monoxide and other toxic gases that are contained in the gas. The machines of the time were inconsistent, prone to hearth bridging, grate clogging and required full user intervention to maintain the machines internal flows.This sometimes involved opening the hopper, dealing with the unleashing of the smoke in your face and then poking down the fuel to re establish combustion in the hearth.
Hopper moisture was a big challenge; as the hearth combustion process released chemically bound moisture that would then migrate up into the hopper in the form of steam. As the the steam would cool this moisture is then soaked up into the fuel media fouling the fuel. Just like in a wood stove wet fuel does not burn very well. This is even more of an issue in a gasifier, this reduces the hearth core temps leading to incomplete processed gas leaving tar behind while also unleashing more moisture. The vicious cycle now begins, this tar and moisture migrates in both directions up and down stream, clogging the gasifiers reduction zone and making the fuel sticky leading to more bridging.
Filtration, is the next thing the user has to deal with. The big part of filtration in the gasification process is cooling the gas. Once the gas is cooled moisture, soot and tar drop out. The end user then has to dispose of this somehow and in today's world thats a no no. The condensate does have uses as it can be used as a natural pesticide and if diluted has very minimal impact environmentally. In addition you have to deal with the media filter, this is generally the next phase of the filtering process and also collects much moisture, soot and tar. Regardless what you use here it must be changed frequently and is very dirty, sticky and again must be properly disposed of.
Tar is simply the nature of the beast; at some point the machine is going to make some tar and if something is not just right in the gasifier tar will be produced that will certainly bypass any filter. Once tar gets into the engine in excess the valve train may be effected. This is generally the cooler intake valve and the valve stem may become sticky. Once the engine has cooled it will glue in its place. Valve push rods can then bend trying to push this sticky or seized up valve. In the case of modern engines where the piston can collide with the valve, well that will require the head pulled a new valve replacement. Excessive tars and soots getting into the engine will foul the oil prematurely, gum up piston rings, carburetors etc. This leads to more frequent oil changes and if left unchecked can lead to premature engine failure.
Getting your engine to run on wood gas; well in today's modern engine you simply turn the key and walah!! It runs! Gasifier systems of the past this just wasn't the case. First you had to make sure fuel is present in the hearth, fill the hopper, check the ash clean out, check filtration, then fire up the machine and wait for combustible gas. Once you could flare the gas off, then you could start the engine. However you also had to adjust air fuel mixture and find just the right mixture before the engine would fire. This sometimes added prolonged effort for starting and hard on engine starters. Back in those we didn't have electronics to self control fuel mixture this was done entirely by the operator making frequent adjustments.
Fuel!! Well in order to run a gasifier you need fuel!! This is a very labor intensive endeavour involving many processes to get a fuel that will work in a gasifier. You first obtain the stock and then it must be broken down and processed. Chipping machines and chunkers are the general machines employed for this task. This process doesn't end there, the fuel media must then be screened sorted for uniformity and then dried to a very low moisture content. If the fuel is not right then all the above comes in play and the user experience is; well not so good. Keeping up with a gasifier is a bit of work as well. Nothing is free running a gasifier of this era took a great deal of work your time has value!
So wow! after you have learned all this it's no wonder this is not a mainstream technology!! Who wants to deal with all that!!?? Right?
Well not so fast; here is the thing, gasification advancements were very few from WWII up until just the last decade. That's not to say there have not been improvements, but most major improvements have come only in the last decade. This is mainly through the use of the now available low cost microcontrollers. Yes indeed these are nothing new; however, not at low cost with the connectivity and capabilities that today's controllers have to offer. Not only the controllers themselves but also other hardware, sensors such as temperature probes, motor controls, touch screen displays, and much more can be obtained easily from the internet. Imagine sourcing all this back in 1995 it would take years and come at big expense!! Simpler to use coding language has really lowered the bar on what can be accomplished. Along with this smarter build construction, cnc machine capability, modern materials, computer aided 3D modeling and the wealth of knowledge that is available to learn from has played into conceiving the next generation of modern systems. Most these advancements have come from new and innovative companies, along with some of the DIY community in the wood gas arena.
So here we are today!! What has changed and why is it viable now?
Well we can only speak for ourselves on what we have accomplished. Thrive Energy Systems parent company Vulcan Gasifier was launched in early 2012 with a very simple and basic gasifier plant based on the Imbert Gasifier. It was really no more complicated than any WWII gasifier, so it had all the issues of a gasifier made in that era. So we had some challenges to overcome and from that point forward development came at a very rapid pace. Automation was quickly employed to automate hopper vibrators and grate actuators to self maintain raw fuel flows. Oxygen sensor driven air fuel mixture controllers were employed to self adjust fuel / air mixtures automatically. Build architecture continually changed to optimize internal processes and flows. We built small and large, we've ran large high performance V8 engines down to just 5 HP single cylinder engines. Then manufacturing integration evolved to lower cost and increase speed. At the end of 2016 Thrive Energy Systems came to be and was the begining of design finalization. At this point we had figured out a lot of things. where the market was and core technologies developed up to this point, were taken as far as we could from a manufacturing perspective. But there were still a few things we needed to address for a modern gasifier system to exist in a modern market.
Fuel!!! It all begins here and this is the backbone to the success of any gasification technology. We needed a solution for a standardized fuel that the end user could obtain easily and would require little effort to produce. We didn't have to look far as it already exist in form of the 1/4" wood pellet. Originally we stayed away from this fuel as most of our clients wanted to be self sustaining and produce their own fuel. So this was the belief and most development made in the early days evolved around chipped fuels. However, after making this fuel ourselves we learned first hand the difficulties and what it took to keep up with our machines. It was a lot of work!! Your time is not free and once we weighed the cost of buying pellets they are a deal!! take my money!! Well this is not going to cut it for all users and is a deal breaker for some. So why not build a machine that can make pellets?? Make a machine that can do it easily? Well that is just what we are going to develop and it will require minimal labor from the end user with a one step process. Raw firewood in and fuel grade pellets come out.
Ok fuel standardization and production is now addressed, but now this changes some things; all of our technology evolved around wood chips!!. As we developed and evolved we learned a great deal with many conceptual designs that could not be implemented with chip fuels. The wood pellet opened that door to these concepts and a whole new breed of gasifier was created. We developed the first ever carburetor for a gasifier and no we're not talking about an air fuel mixture carburetor to the engine. This is a carburetor for the gasfiers reactor itself! Many discoveries were made with this new concept and this solves many of the issues presented in this writing. Number one is hopper gases were eliminated with this device, so no moisture ever gets into the hopper. Now we are reversing the vicious cycle, our core temps now remain stable and run hotter, moistures and tars are fully cracked, and later in filter process condensate is nearly eliminated!!.
So now the core technology is developed, now how do we manufacture this, cost effectively with high quality. On the 2016 gasifier we began building a new system that had a shared collection tank. This was a one piece tank that was partitioned off to each individual portion of the gasifier and filtration components. This included the char ash bin, cyclone trap and condensate tank shared between the cooler and media filter. This eliminated creating multiple collection tanks for each component of the gasifier while also serving as a foundation to integrate the entire system together. This alone was huge cost and time savings. The 2019 models we expanded on this concept building the machine in modular stacked sections vs building individual sections horizontally. This again will save time with less build complexity, less parts to manufacture and allow for integrated manufacturing processes.
Making the machine user friendly; this is where full automation comes in. At this point we had already fully developed and tested proven automation; however, this was done in individual modules. In 2017 work began with operating software development (Thrive OS) that would be the engine to combine and drive all systems together. This is ran from a single board computer coupled a to a 7" touchscreen display with an interactive GUI. Not only is this a push button opperted machine but the machine tells you what it's doing and tells you what to do next in the case its running in semi auto mode. In the case of running full auto mode you simply initiate "Cycle Start" and the machine fires up completely on its own including engine cranking. To shut down simply initiate the shut down mode. In the case you have a battery storage system with charger, the machine can be put into auto gen start mode. In this mode the machine will self run and shut down thus charging the battery bank when needed and shutting down when charged. In this configuration the machine fuel consumption and efficiency will increase exponentially. Base fuel consumption is 2.6 lbs pr kW/hr produced. with this mode activated it can be as low as 1 lb pr kW/hr. The fuel hopper on the Flex Power System Standard could potentially last a week on a residential off grid home install.
Tar!! How do we deal with that nasty stuff!! Ok well the condensate issue has already been, addressed but tars and filtering? Well the gasifier should not make tar in the first place and in general this will be the case with our technology. However tar production can still occur “if it can happen it will” and this will be the case with any gasifier. We no longer use any media filtering at all to eliminate that mess. The vessel on our machine that would be considered on most traditional systems is our condenser. The gas as it is flowing through the filtering is constantly turning over and over and doing so very rapidly. Debris carried in the gas are constantly dropping out during its voyage through the system. After the gas has left the gasifier we mix the air into the gas and then enter it into our final filter system. This is a series cyclonic filtering device that uses strong centrifugal forces at the very end of the cooling cycle of the gas. This is the final point where all tars and moistures should be fully condensed and can readily be forced out through this process. This condensing process is where a lot of designs fail. If tar is still suspended in gas form it will bypass all filters period. Then drop out later in the form of tar. In the case our final filter fails to catch any remaining tars, we have one last and final defence. This is a sensor specifically designed to detect tar at the engine. It is a rather simple device that when tar is present the sticky tar will accumulate onto and bridge a gap between two elements closing a circuit. This sensor does need to be cleaned if fouled; however, this small amount of work is nothing compared to engine repair or overhaul. In general operation this sensor should never be triggered.
So now a new question: Have we achieved a viable gasification to electric power and heat system for today's market? Let us know what you think and contact us!!!