I’m looking for some sort of sensor that would tell me the relative heating value of gas as it is produced. I think some sort of device must have been used for coal gas. Does anyone know about this?
Rindert
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how about the speedometer on a woodgas truck? 
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Hi Rindert,
I am using one, but those are very expensive ( about 30k $)
even with a smile and tongue in cheek, somehow similar as Don said… but i use a generator to measure that… ( how much amps/watts can i pull from my generator before it bogs down… )
Somehow helpful as well : the Co2 level of the gas can be used as indicator ( lower is better )
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Regarding the quality of the gas, a good indicator is also the vacuum gauge in the intake manifold, namely, your generator has a centrifugal regulator, which ensures constant engine speed. If the gas is of poor quality, the regulator will keep the throttle valve more open and the vacuum will be lower. If the gas is of good quality and strong, the throttle valve will be more closed and the vacuum will be higher (note that the generator load is the same in both cases).
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Hmmm, they have similar things out there for detecting gas leaks, measuring a persons blood alcohol content, & etc. I feel that a very small fuel cell could be made on a silicone chip just to serve as a sensor. There’s got to be something out there.
Rindert
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You might be able to use a calorimeter to measure the heat content. I made a marginal one for a student lab some years back. It had a small torch burner inside a one-inch pyrex tube. Two flow meters (rotameters) measured, or more precisely, set the flow of air and fuel gas. If you know the liters/minute (or whatever units you like) of both gases and their specific heats, the input temperature and output temperature, and guess at the flue gases and specific heats, you can calculate the heat content of the fuel. Above the burner, I used a chunk of stainless steel pot scrubber to act as a sort of temperature integrator, with a thermocouple burried in it. I think the measurements were within 10-15% of standard values, which was good enough to get the idea across to students, and simple enough to look at and understand. If you just need relative numbers, and don’t mind some fiddling, it might be useful. You wouldn’t need specific heats and all that. Just fix the air and gas flow, and higher temperature means better fuel.
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I started off thinking about something like that. I was going to use a peristaltic pump to precisely control air and gas flows. But that’s a mess. They have a methanol cell on a chip, why not one that uses syngas. I know it’s out there, I just have to find it. It’s all about knowing the name of whatever widget you are trying to find.
Rindert
Link to MeOH cell on a chip.
Hi Rindert, if i remember correctly, there is some stuff about gas sampling/analyzis in the old FAO publication, absolutely not up to date, i know, but some system layouts that could be useful?
As Koen points out, a simple co2 meter could be very helpful, these are pretty easy to find used, of good quality, these where used alot for “tuning” boilers, home and industrial, for gas, coal, and oil fired.
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Maybe something like this would work:
These sensors seem to require oxygen to work, and top out around 1000 ppm. They are pretty cheap, and might do the job if you could figure a way to dilute your fuel gas with air, perhaps a syringe pump with stops or something. There are industrial versions with lots of stainless parts if you really want to spend money.
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There is valid reason why gasoline here in the US-of-A is pump dispensed with an averaged octane rating of Research derived and then the Motor tested method . . . RM/2.
In for actually working engines; Lab results or on even Dynamometer runs are just starting reference points.
In working engines ALL factors will insist on being accounted for.
RindartW., making motor grade gas in a gasifier your output results will vary from beginning; mid-batch; ending of a batch loading quite a bit.
Just like olives pressing for oils. Three primary grades.
Just like all other organic processes. Making the pancakes. Baking cookies in a home oven.
Until Mr Rockefeller worked with an actual chemical engineer to test; and then learned to only sell a Standardized canned product of illuminating kerosene; and soon later gasoline these had been hugely varying, and unpredictably, even dangerous to use.
Take to heart just a simple output gas CO2 measuring. CO2 is the internally made mid-level gas you are trying to create; and then Reduction convert to a reactive CO fuel gas. You want a low final CO2 output.
In a heating appliance application, atmospheric oxidized you want at least a post combustion level of 11% CO2. 16% CO2 is considered ideal.
In working IC engines exhausts, post work, you want the same high CO2 ranges. With good working power this tells you your input fuels were quality and your high-speed/high-pressure combustion process were effective.
Myself I am happy with actual working engines power making results.
I intentional do not feed the Beasts of numbers comparisons.
All of the words and jibber-jabber about motor fuels calorific measures are imaginative bunk. Like the old Greeks, geeking conceiving something then makes it valid, and real. Nope. Nope. Real is real and bites hard. All else is imaginative speculations, hopes and dreams.
Steve Unruh
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I needed the same thing when I wanted the automation to start the engine itself, after the wood gas generator reaches its operating parameters. Later, I also wanted to maintain the quality of wood gas at a set level.
The thought was this:
- the air flow with a stable flow rate is divided into 2 pipes of the same cross-section
- a stream of wood gas with a stable pressure is supplied by 2 gas nozzles into each of these pipes
- in each pipe there is an electric spark plug and a flame control sensor, as in domestic gas boilers (ionization)
- by adjusting the supply of wood gas using PWM, we determine the extreme values of its flammability.
Further, knowing the boundaries at which wood gas burns, we regulate either the main air and wood gas mixer entering the engine, or the temperature and air supply to the wood gasification zone to maintain a more or less constant composition of the gas in terms of its flammability.
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So I end up thinking an explosimeter is the closest thing to what I really want. I just have to figure out how to mix precise quantities of air with the sample before it goes into the combustion chamber.
Rindert
Here is a link to an explanation of how an explosimeter works.
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I think this is the principle behind the SGX Sensortech meter I mentioned above: Gas quality meter? - #9 by FruitvaleFarmer
These are MEMS (Micro-Electro-Mechanical) devices fabricated with integrated circuit methods, so they’re small and inexpensive. Some of them use a catalyst layer on the heated part to increase sensitivity. I’m not sure about the one in the link.
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Okay Kent. I’ll took into that MiCS5524.
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