What are Different Types of Synthetic Fuels?
Synthetic fuels are any liquid fuel manufactured from something that has energy - like coal, natural gas, tar sands, or biomass. By contrast, a natural fuel would be something like oil. Synthetic fuels are frequently referred to as synfuels.
In 1944, when the Synthetic Liquid Fuels Program was established as a program run by the US Bureau of Mines, the United States government supported the production of synthetic fuels with investment. As a result, there has been a major impetus for gas and oil companies to use them, as many do - for example Shell, Exxon, Statoil, Rentech, and Syntroleum. However, this synthetic fuels program was halted by Congress in 1985, after spending $8 billion US Dollars (USD) over a 40 year period. In the 1970s, a synfuel tax credit program was established, continuing the push towards synthetic fuels. TECO, Progress Energy, DTE, and Marriott have taken advantage.
Synthetic fuels are classified based on what feedstock was used to create them. By far, the three most prominent processes are Coal-To-Liquids (CTL), Gas-To-Liquids (GTL) and Biomass-To-Liquids (BTL).
The widest-used form of synthetic fuel is liquefied coal and its derivatives. The Fischer-Tropsch process, developed by Nazi Germany and used by Sasol in South Africa today is one of the most used for converting coal, as well as biomass or natural gas, into synthetic fuels.
Whatever you're using to produce the synthetic fuels, the first step is to convert it into carbon monoxide and hydrogen gas. In the gas of natural gases like methane, this requires partial combustion. For coal or biomass, gasification is necessary, which means combining the material with water and oxygen or air at high temperatures. The carbon in the coal combines with oxygen in the water to create carbon monoxide, while the leftover hydrogen atoms create hydrogen gas. This produces a substance called syngas, which can itself by used as a fuel, or further processed into diesel or another derivative.
Diesel used to be made only by petroleum, hence it was called petrodiesel. Today, other substances such as biomass or natural gas are used to make it, hence biodiesel.
@ GiraffeEars- If you are converting to SVO (vegetable oil/fryer grease) you will need further modifications. A TDI is a Turbo Direct Injection Diesel, so the viscosity of the fuel plays a large part in the performance of the vehicle. I would strongly advise that you stay away from two tank systems and use something like an elsbett single tanks system. TDI engines depend on injector pressures reaching about 1600 barr (espresso is made at 12-16 barr). You will need a system that can heat the oil to almost 300 degrees before it hits the injectors.
One of the best set-ups for your TDI is an Elsbett Single Tank system. It will take about 15-20 hours to install, and requires some mechanical skill. You will essentially be installing new injectors, filter heaters, fuel lines, relays, coolant heat exchangers, oil temperature sensors and glow plugs. It’s a big job, but this system is the best, and you can mix biodiesel, diesel, and SVO.
@ GiraffeEars- If you want to run your TDI on Biodiesel, you are in luck. There is only one major modification and a couple of filter changes necessary to convert to biodiesel. TO convert your vehicle, you will need to replace your fuel return lines (the ones returning fuel from the injectors to the tank) with synthetic lines. These are the only non-synthetic lines, and they will eventually corrode from running the cleaner alcoholic biodiesel.
Once you change the lines, you should start with B20 for about four or five tanks to flush the petrodiesel sludge from your tank. Once the car begins to sputter at high speeds or become sluggish, change the fuel filter. Now run B100 until the same thing happens again. Change the filter one more time and you are ready to go. Biodiesel effectively cleans all of the petrodiesel sludge out of your fuel system, causing it to collect in the filter. This is why it needs to be changed a couple of times. I hope this helps you make the move to renewable fuels!
How hard is it to convert a vehicle to biodiesel fuels? I have an old Jetta TDI that I was planning on getting rid of, but I was thinking about converting it to run on fry grease. I am mechanically inclined, so I would prefer to do this myself. What is involved, and what would a conversion cost?
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