I was pleasantly surprised last week to see Exxon running a TV commercial on the fuel reformer that they have been working on since at least 2007
. If you haven't seen the commercial yet you can take a moment and go to the Exxon site and view it at this link
. I am writing this story because I really think that everyone needs to understand what the technology is and how it works. This single device could be the key to accomplishing our goals of reversing Climate Change, allowing us to convert to a green energy economy in the shortest time possible and making our country completely energy independent. How this could happen is going to be the focus of this story.
I have been a strong proponent of hydrogen fuel since the mid 1990's when I first started researching the electrolysis of water and searching for ways to make that process more energy efficient.I had a website devoted to that effort
and then a blog on hydrogen and climate change
. I have always been an advocate for the environment and for preserving our unspoiled natural heritage at least on a personal level. I was writing about Climate Change from a scientific perspective before Al Gore picked up the concept and ran with it. My point in saying this is that I am not some fly by night energy advocate who is easily won over to the side of the "evil" oil companies. In fact, as I will explain, fuel reformers go beyond oil and that is part of the beauty of them.
Consumer and Commercial Applications of Steam Reformation Considerations on Fuel Economy and Climate Change
Some of the m pressing and controversial issues in the world today are the dwindling supply of naturally available crude oil, the rapid climate change and the development of the third world. As in the past, humanity is rallying to meet these challenges. Many people and Scientists alike, agree that our energy future is going to be diversified, with energy sources such as wind, solar and ocean power playing larger roles. Many experts agree however that hydrogen could be the answer to most of our energy requirements, including that of fuel to the crucial and ever increasing transportation sector. Hydrogen can also play a major role in rectifying some of those global problems mentioned above.
However hydrogen energy faces many challenges before it can truly assume a major role as an energy source. Some of the biggest of these hurdles are the production, storage and distribution of this fuel type, since our existing infrastructure is, for the most part, not designed around such a gaseous fuel.
In the case of hydrogen as a fuel for transportation there is however an alternative way in which to produce hydrogen “as required” and “on demand” and “without a need for storage” which differs from those processes currently being popularized. Hydrogen energy can be easily and safely introduced into the economy and this paper will explain that process and how it can be accomplished. This alternative technology involves a fairly simple process which is called Steam Reforming or better still On Board Steam Reforming.
What is Steam Reformation?
Steam reforming, or more correctly the reaction “partial oxidation of hydrocarbons and water and on a catalyst bed” is actually the process currently being used in industry to produce most of the world’s commercial hydrogen on a large scale and in large volumes. In fact many years ago the first type of gas that was used to light street lamps before the discovery of methane was a combination of hydrogen and carbon monoxide, more commonly referred to as “Street Gas”. This gas was produced by passing 1000 degree super heated steam over carbon (coal). This chemical reaction is as follows:- 2C + 2H2O -à 2CO + 2H2. A similar process can be achieved using most hydrocarbons.
In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons can be gases (e.g. methane and propane), liquids (e.g. hexane and benzene), waxes or low melting solids (e.g. paraffin wax and naphthalene) or polymers (e.g. polyethylene, polypropylene and polystyrene).
There are four classifications or basic types of hydrocarbons;-
1) Saturated hydrocarbons (alkanes) are the most simple of the hydrocarbon species and are composed entirely of single bonds and are saturated with hydrogen; they are the basis of petroleum fuels and are either found as linear or branched species of unlimited number. The general formula for saturated hydrocarbons is CnH2n + 2 (assuming non-cyclic structures).
2) Unsaturated hydrocarbons have one or more double or triple bonds between carbon atoms. Those with one double bond are called alkenes, with the formula CnH2n (assuming non-cyclic structures). Those containing triple bonds are called alkynes.
3) Cycloalkanes are hydrocarbons containing one or more carbon rings to which hydrogen atoms are attached. The general formula for a saturated hydrocarbon containing one ring is CnH2n Aromatic hydrocarbons, also known as arenes which have at least one aromatic ring.
*Even non hydrocarbons such as alcohol or sugar can be broken down by this process or chemical reaction. In the case of hydrocarbons though, as opposed to pure carbon, a catalyst such as nickel or platinum is required within the system for the reaction to be successful.
Basically during the reaction of Steam reforming, a mixture of hydrocarbon and water are REFORMED on the surface of the catalyst to produce a “Syngas” which is a form of fuel. Syngas (from synthesis gas) is the name given to a gas mixture that contains varying amounts of carbon monoxide and hydrogen generated by the gasification of a carbon containing fuel to a gaseous product with a heating, energy or fuel value.
In the case of a simple hydrocarbon such as methane the reforming reaction looks like this: CH4 + H2O --à CO + 3H2. Both of the gasses produced by this reaction, hydrogen and carbon monoxide, can be used as fuels. Carbon monoxide is already considered to be a low grade industrial fuel. Or a second step can be added during which more watter is added creating CO2 and a pure hydrogen fuel for the vehicle.
One of the most fascinating things to note here is the fact that in the above reaction between water and methane, fully 1/3 of the hydrogen gas produced comes from the WATER, not the hydrocarbon
. In the same process using more complex hydrocarbons such as gasoline of diesel fuel up to 2/3 of the hydrogen fuel produced comes from the water, not the hydrocarbon
Steam reforming: CH4 + H2O → CO + 3H2 ΔH298 = 206 kJ/mol
CO2 reforming: CH4 + CO2 → 2CO + 2H2 ΔH298 = 247 kJ/mol
Partial oxidation: CH4 + 1/2O2 → CO + 2H2 ΔH298 = -36 kJ/mol
The obvious conclusion then is the utilization of an on board steam reformer to produce a syngas fuel composed on H2(g) and CO(g). By doing this in situ on a vehicle, the steam reformer will potentially reduce the hydrocarbon fuel consumption of that vehicle by up to 60% and at the same time reduce the CO2 pollution by an equal percentage. This is simply because up to 60% of the fuel to run the vehicle will now be coming from the water used in the reforming process.
The beauty of this process is that it can easily be adapted to work with both new and existing vehicles. The steam reformer can be fitted (retro fitted) to a vehicle in place of the standard, factory fitted fuel delivery system. Every form of transportation from passenger cars to heavy trucks to ships and jet aircraft could be modified to use this syngas as a primary fuel or as a dual fuel mixed with the vehicles regular fuel. If every vehicle in the world that uses hydrocarbon fuel was converted to using an on board reformer, this would cut the world’s use of, or dependence on petroleum by 30 to 60 percent and as noted above reduce CO 2 pollution by an equal percentage. Another advantage is that the raw materials required to produce this syngas (hydrocarbons and water) are readily available, can be stored easily, transported and distributed totally and safely by our existing infrastructure with no major modifications.
The On Board Steam Reformer
The process is relatively simple, well understood and can be likened to a system which is already in use (in a somewhat different application) and on most passenger vehicles today. These similar systems are referred to as Catalytic converters, which are presently fitted on most modern exhaust systems. Catalytic converters consist of a ceramic structure coated with a metal catalyst, usually platinum, rhodium and/or palladium. The Catalytic converter is a device fitted into the vehicles exhaust system that exposes the maximum surface area of catalyst to the exhaust stream, while also minimizing the amount of catalyst required (they are very expensive
due to the use of precious metals including platinum, which is worth up to $1,200 an ounce)
In the cross section of a Standard Catalytic Converter below please note the design as this is important in making a comparison between a catalytic converter and the on board fuel reformer which would use a Hi-Flow Catalyst membrane. The point here is to show that the two are similar enough to indicate that an on board fuel reformer could be developed that would be fully functional and yet not be prohibitively expensive. Of course there will be necessary differences between the two but the comparison should be sufficient to prove the point.
How the fuel reformer works
A mixture of hydrocarbon feedstock and water is injected into the reformer, and onto the catalyst, where a reaction takes place. The surface of the preheated catalyst has an elevated temperature, therefore a reaction takes place and syngas is produced. This may sound “too simple” or even seem daunting, except for the fact that the reaction itself is exothermic and can proceed as a self sustained reaction. An exothermic reaction simply means that the reaction produces enough heat to sustain itself. The syngas produced as a result of the above reaction is extracted and becomes the fuel used to power the vehicle.
Designing the Steam Reformer
The catalytic steam reformer is a fairly simple device constructed using an internal screen, (or a bank of several screens) fabricated with a ceramic structure or wire mesh coated with a metal catalyst, usually platinum, rhodium and/or palladium. The catalyst is then preheated (flash heated) electrically to a temperature of 1000 degrees Kelvin. The water and hydrocarbon mixture reacts exothermically on the hot catalyst coated membrane and syngas is produced. The reactor unit is insulated with ceramic and the whole unit is then encased in a non conductive, non spark emitting material like for example, carbon fibre.
Steam reforming in a Catalytic burner / reformer device is very well suited to on board applications, because of its simplicity, lack of moving parts and ease of maintenance.
Advantages of Reformed fuel
Syngas or hydrogen as a fuel for the internal combustion engine provides many advantages.
These are as follows:-
Reduced Emissions: By producing syngas fuel from an equal mixture of standard hydrocarbon fuel i.e. diesel, petrol or methane and water, the emissions produced contain half the CO 2 which would normally be present in exhaust gas. By adjusting the balance of the hydrocarbon / water fuel mixture, one can determine the amount of CO2 which is released into the atmosphere by between 30 and 60 percent.
Reduced costs: The cost of operating the vehicle is reduced in relation to the amount of water present in the fuel to the reformer. With a 50 / 50 mixture, the cost of running the vehicle is quite simply halved.
There are other hidden savings which should also be taken into consideration.
Reduced wear and tear and increased power: Syngas has a much higher ignition velocity than normal fossil fuels. Hydrogen burns with a ignition speed approaching 40.000 feet per second, whereas diesel has an ignition speed of 1/10th of that or 4.000 feet per second.
In a standard combustion engine the fuel is mixed with air and ignited in the top of the cylinder according to its best operational function in conjunction with the flame propagation of diesel / petrol and air. The resulting explosion forces the piston down through its cycle, thus converting the chemical energy into torque on the crank shaft. It is this torque which propels the vehicle forward. But…because most liquid fuels have relatively slow flame propagation times, the ignition has to take place at a considerable amount of time before the piston reaches the top of its cycle (in rotation), or Top Dead Center (TDC) therefore encouraging backward pressure on the piston and crankshaft. This backward pressure results in a loss of energy, excess wear, tear and load on the bearings, stress on the cylinder, and increased wear on the cylinder walls. Furthermore, internal lubricants are burnt off, mingling with the fuel to form a film which increases emissions.
In addition to the above, the slower the time of flame propagation, the higher the temperature in the cylinder and therefore the higher the temperature of the gas leaving the cylinder. When calculating heat management of an internal combustion engine, the higher the temperature in the cylinder and the lower the temperature of the gas leaving the cylinder, equates to the highest efficiency. In conclusion if the gas leaving the cylinder is cold, then the energy has been obtained, and if it’s warm the energy has been lost.
The general rule of thumb applied when calculating the efficiency of an internal combustion engine is that 1/3rd of the energy created goes to the crankshaft, 1/3rd goes to the cooling system (radiator) and 1/3rd goes into the exhaust. From the proportion going to the crankshaft, one can also subtract the energy taken away to parasitic loads, i.e. the air conditioner, the cooling fan and the alternator. A standard petrol engine is only between 17 – 22% efficient, diesel engines range between 35 -44 % efficient.
In summery the petrol and diesel fuelled internal combustion engines are very inefficient and have a negative impact on the environment and contribute to climate change.
However, in a syngas or hydrogen fuelled vehicle, the fuel is ignited or burnt at TDC, at the very top of the pistons cycle, so all the energy is concentrated to moving the vehicle forward. The syngas burns or explodes so quickly that heat doesn’t propagate to the walls of the cylinder, there is no back pressure or strain on the piston and crankshaft, no stress on the bearings and no wear and tear on the cylinder walls. The levels of emissions released in the exhaust are also dramatically reduced.
In conclusion running an internal combustion engine on Hydrogen / syngas fuel is very efficient, in fact up to 54% efficiency has been achieved. Not only does hydrogen provide many thermodynamic and financial advantages but the engine will be environmentally friendly as well.
*Note: when running a conventional internal combustion engine on hydrogen the ignition timing must be adjusted to suit the fuel combustion rate. This can be easily done by developing a set of markers on the flywheel, so one can adjust the magneto in a petrol engine to fire the spark plug, or in the case of diesel engines, inject the fuel in accordance with the fuel selected. One must remove the key which times the flywheel for operation on diesel or petrol, and adjust the setting so that the magneto ignites at (TDC) or just prior to the power stroke.
Variations of design
There are several different ways in which to design and build a Steam Reformer depending on the application. In addition there are several pre and post reaction treatments or processes which can help improve the efficiency and life of a reformer and increase the production of hydrogen. All extras, cost extra, add to the weight and the complexity and are not necessary in our “keep it simple” low cost steam reformer.
Although most of the reformers being developed today are being geared toward producing hydrogen fuel for fuel cell vehicles, there seems to be no reason why this technology could not be adapted to produce fuel on board any traditional transportation vehicle as well a supplying already existing power plants. Judging from the descriptions of all the steam reformer systems developed and the uncanny likeness of our Catalytic Burner / Reformer to the more common Catalytic Converter, it seemed obvious that they are similar enough to suggest that a relatively inexpensive aftermarket reformer can be fairly easily developed.
The economic advantages this reformer provides in fuel savings alone to the operators of heavy trucks is an obvious incentive for further research. And because much of our current CO2 air pollution is produced by jet aircraft the benefit of such a system for jet aircraft is also obvious as well as the fuel savings to the owners of the aircraft. This coupled with carbon credits will make these systems a win/win proposition for the operators who use them and for the future environmental health of our Worlds atmosphere.
Mike Johnston & James Thorpe August 2007