Patent Application
20050274107
This invention relates to reforming liquid hydrocarbon fuels without vaporizing the fuel by means of direct injection of the liquid hydrocarbon fuel through an atomizing nozzle, into either hot engine exhaust or preheated humidified air, upstream of a reformer such as a catalytic partial oxidizer (CPO) or a non-catalytic, homogenous partial oxidizer (POX), or autothermal reformer (ATR).
The conventional wisdom for reforming liquid hydrocarbon fuels, such as gasoline and diesel fuel, is that the liquid fuel must be vaporized before feeding into a reformer, such as a CPO, POX, or ATR.
Referring to
The exhaust clean-up processing 16 receives syngas, which is a reformate including hydrogen, some CO and some CO2, as is known, over a conduit 17 from a reformer which in this embodiment is a CPO 18. Examples of the exhaust clean-up processing may be found in U.S. patent applications having serial numbers and filed as follows: Ser. No. 10/243,105, Sep. 13, 2002; Ser. No. 10/309,712, Dec. 4, 2002; and Ser. No. 10/658,494, Sep. 8, 2003. The manner of using the syngas which is produced in accordance with the invention is not relevant to the invention; instead, the invention relates to the manner of producing the syngas for emission reduction of internal combustion engines.
In the prior art, fuel in the line 10 is vaporized in a vaporizer 65 which is raised to a sufficiently high temperature by a heater 66 which surrounds the vaporizer. The vaporized fuel in a conduit 68 has preheated air mixed with it from a conduit 69, both of which are provided to a mixer 70 at the entrance to the CPO 18 (or other reformer).
An alternative approach known to the prior art is illustrated in
Vaporizing liquid fuels, especially diesel fuel, can cause coke build-up within the vaporizer, and contributes coke particulates into the flow into the reformer, which causes deactivation of the catalyst. The vaporizer adds to the cost, weight and complexity of the system.
Objects of the invention include: eliminating the need for a separate vaporizer for liquid hydrocarbon fuel feed stock being fed to a reformer; eliminating the problems due to coke formation in the reformation of liquid hydrocarbon fuels; eliminating catalyst deactivation due to coke; improved generation of syngas for use in regenerating NOx and particulate adsorbers in internal combustion engine systems; improved generation of hydrogen from liquid hydrocarbon fuels; and reduced cost of liquid hydrocarbon fuel reformers.
According to the present invention, liquid hydrocarbon fuel is injected directly into the hot engine exhaust of a diesel engine, or preheated humidified air, at the inlet to a hydrocarbon fuel reformer, such as a CPO, a POX or an ATR. A high degree of mixing of the liquid hydrocarbon fuel with the oxygen contained in either the engine exhaust or in the humidified air is accomplished simultaneously with the gas assisted atomization and resultant vaporization of the liquid hydrocarbon fuel.
According further to the invention, a mixer, such as inert ceramic foam, is disposed between an atomizing nozzle and the reformer. In the case of a CPO reformer, the radiation heat causes the mixer to achieve high temperature, which may be on the order of between 700° C. (1292° F.) and 1200° C. (2192° F.). The mix of heated oxygen and vaporized fuel causes an initial partial reformation of the hydrocarbon fuel into its constituents prior to reaching the CPO reformer itself. This prereformation has been referred to, and is identified herein as a “cold flame” reformation process. Use of the cold flame process not only provides a more complete reformation in the reformer, but also reduces the peak temperature of the CPO which thus reduces the long term degradation of the CPO catalyst. Use of the invention indicates that the yield of hydrogen and carbon monoxide after several hundred hours is within about one or two percent of the initial yield. This shows that deterioration of the catalyst is minimal when utilizing the present invention.
In accordance further with the invention, atomizing fuel and use of a glow plug igniter allows immediate light off of very rich air/fuel mixtures (air/fuel about 0.014), even though the lower limit of air/fuel ratios for flammability is generally considered to be 0.2, and light off of the CPO reformer at about 175° C. (350° F.), which is a much lower temperature than the 350° C. (660° F.) nominally required for light off without the invention.
In further accord with the invention, a hydrocarbon fuel igniter comprises a catalyst coated heater wire.
Other objects, features and advantages of the present invention will become more apparent in the light of the following detailed description of exemplary embodiments thereof, as illustrated in the accompanying drawing.
In a first embodiment of the invention illustrated in
In accordance with the invention, the fuel is at ambient temperature, and it is not vaporized prior to injection into the mixing chamber 21, but is simply atomized as it is injected through the atomizing nozzle 22 into the mix within the mixing chamber 21 where it vaporizes. The engine exhaust passing through the valve 25 supplies oxygen and moisture for the catalytic reformation process in the CPO 18.
In accordance with the invention, utilization of the inert ceramic foam 19 begins the reformation process by converting some of the fuel into some of its constituents. The fuel also consumes some oxygen which helps to reduce the peak temperature of the CPO, so that the CPO catalyst will last longer and the process will be more complete.
Referring to
The embodiment of
In the embodiment of
The invention as described, utilizing an atomizing fuel nozzle to eliminate the need for a vaporizer for the liquid hydrocarbon fuel, may thus find significant application in cleaning up internal combustion engine exhaust, such as in particulate removal devices and NOx removal devices. The invention, however, may also be used other than in vehicles with internal combustion engines.
Referring to
The exhaust of the CPO 18, which is on the order of 700° C. to 900° C. (1292° F. to 1652° F.), is passed through a conduit 53 to the heat exchanger 48, thereby to raise the temperature of the inlet air to on the order of 300° C. to 500° C. (572° F. to 932° F.). The output in a conduit 55 is reformate, sometimes referred to as “syngas”, which includes hydrogen, CO and some CO2, along with nitrogen, steam and unconverted hydrocarbons, all as is known to the art.
In the embodiment of
The reformate provided through the heat exchanger 48 in the conduit 55 may either be utilized as is, or it may undergo further processing, such as water/gas shift reactions, to convert CO to provide more hydrogen, and a preferential CO oxidizer, to reduce CO. The use which is made of the product of the embodiment of
The atomized liquid fuel within the mixing chamber 21, particularly if it is gasoline, is extremely explosive. Therefore, the igniter should not be a spark plug for safety reasons. Instead of using a glow plug, however, the igniter may comprise, as shown in
In the invention, only sufficient oxygen should be used to reach the CPO temperature, any additional oxygen merely reducing the hydrogen yield. Without use of a catalyst, such as a homogeneous POX, the glow plug must be at a much higher temperature, and must be energized continuously.
All of the aforementioned patent applications are incorporated herein by reference.
Thus, although the invention has been shown and described with respect to exemplary embodiments thereof, it should be understood by those skilled in the art that the foregoing and various other changes, omissions and additions may be made therein and thereto, without departing from the spirit and scope of the invention.
