TECHNICAL FIELD

The subject matter as described herein, in general relates to production of hydrogen and in particular relates to the production of hydrogen on-board a vehicle.

BACKGROUND

Hydrogen is used as an alternative or substitute to conventional liquid and gaseous fuels for various applications, such as for transportation. Hydrogen may be used directly as a fuel in an internal combustion engine of a vehicle, or it may be used as a fuel in fuel cells to propel fuel cell vehicles. With stringent environmental legislations in place, hydrogen finds wide applications as a fuel because of its low emissions and high combustion efficiency.

Hydrogen generally exists abundantly in nature in the form of hydrocarbons and water. To produce hydrogen on a commercial scale, various methods are employed. Generally, hydrogen is produced by reforming hydrocarbons or their derivatives, such as Methyl alcohol, in the presence of steam at high pressure and temperature, for example, at about the supercritical point of hydrocarbon and water mixture.

Further, conventional systems for producing hydrogen require bulky reactors for carrying out the reformation reaction. These reactors use electric heating coils to attain high temperature and require a high capacity power source for operation.

SUMMARY

The present subject matter described herein relates to a system for producing hydrogen on-board a vehicle. In an embodiment, the system includes a hydrocarbon container mounted on the vehicle, and a reforming medium container mounted on the vehicle and connected to the hydrocarbon container. The hydrocarbon container stores a hydrocarbon and the reforming medium container stores a reforming medium. The system further includes a reactor connected to the hydrocarbon container and to the reforming medium container to receive the hydrocarbon compound and the reforming medium, respectively. According to an aspect of the present subject matter, the reactor is mounted on the vehicle and coupled to an internal combustion engine of the vehicle to obtain heat for reforming the hydrocarbon compound in presence of the reforming medium and for producing hydrogen.

These and other features, aspects, and advantages of the present subject matter will be better understood with reference to the following description and appended claims. This summary is provided to introduce a selection of concepts in a simplified form. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.

BRIEF DESCRIPTION OF DRAWINGS

The above and other features, aspects, and advantages of the subject matter will be better understood with regard to the following description, appended claims, and accompanying drawings where:

Fig. 1 illustrates a schematic of a system for producing hydrogen on-board a vehicle, according to an embodiment of the present subject matter.

Fig. 2(a), Fig. 2(b), and Fig. 2(c) illustrate various implementations of the system for producing hydrogen on board a vehicle.

DETAILED DESCRIPTION

The present subject matter as described herein relates to production of hydrogen onboard a vehicle, i.e., on-board hydrogen production.

Hydrogen is generally produced when a pressurized mixture of a hydrocarbon, or a derivative of a hydrocarbon, and a reforming medium is heated to high temperature. A hydrocarbon or a derivative of a hydrocarbon or a mixture thereof is referred to as hydrocarbon compound hereinafter.

At such high temperatures, the reforming medium reacts with the hydrocarbon compound to produce hydrogen. Conventional systems generally use electric elements to heat the mixture of the hydrocarbon compound and the reforming medium to a high temperature, for the reformation reaction. Moreover, the systems use a bulky vessel to heat a large amount of mixture, for example, for commercial production of hydrogen. Such systems are, however, inapt for on-board production of hydrogen for use in transport applications because of energy and size requirements.

To this end a system is described to produce hydrogen on-board a vehicle. The vehicle may be a two-wheeler or a four-wheeler, which is powered by an internal combustion engine, here matter referred to as an engine.

According to an aspect of the present subject matter, the system utilizes heat generated by the engine, such as heat of combustion which is absorbed by a cylinder head or waste heat from exhaust gases emitted from the engine. This heat is used further to heat a hydrocarbon compound and a reforming medium to a high temperature, for example, close to a supercritical condition of the reforming medium. The hydrocarbon compounds may include hydrocarbons, such as paraffins, napthenes, olefins, and arenes, and hydrocarbon derivatives, such as alcohols, esters, and carboxylic acids, or a mixture thereof Further, the reforming medium may include, for example, water.

According to an embodiment, the system includes a reforming reactor to achieve the reformation of the hydrocarbon compound. The reforming reactor is supplied with a mixture of the hydrocarbon compound and a reforming medium. In one implementation, the hydrocarbon compound, for example, Methyl alcohol, undergoes the reformation reaction in presence of the reforming medium inside the reforming reactor and produces hydrogen and carbon dioxide. In addition, the system includes a pump to pressurize the mixture of the hydrocarbon compound and the reforming medium to a predetermined pressure, for example, a critical pressure of the reforming medium. The hydrocarbon compound then reacts with the reforming medium at high temperature and high pressure to produce hydrogen.

In another implementation, a hydrocarbon compound, for example, a fossil fuel may be reformed in the reforming reactor to produce the hydrogen and the carbon monoxide as the products. Further, in said implementation, the system may further include a secondary reactor, in which the carbon monoxide from the reforming reactor is used as a reactant to further produce hydrogen.

The system as described herein employs a small reactor for carrying out the reformation reaction, since the amount of the hydrocarbon compound and the reforming medium is relatively small. Further, the system uses the heat of the exhaust gases to heat the hydrocarbon compound and the reforming medium to the required temperature to produce hydrogen to be directly used as fuel. Hence, the system as described can be adapted for use on-board a vehicle to generate and supply hydrogen as fuel supplement to the vehicle, as and when required, which in turn helps to achieve better fuel economy, more power, and less emissions.

Fig. 1 illustrates a schematic of a system 100, which produces hydrogen on-board a vehicle. In an embodiment, the system 100 includes a hydrocarbon container 102, a reforming medium container 104, a pump 106, a reactor 108, and a separator 110. The hydrocarbon container 102 stores a hydrocarbon compound, which is reformed to produce hydrogen. The hydrocarbon compound may be, for example, a hydrocarbon, such as a paraffin, an alcohol, a napthene, an olefin, an aromatic, or a derivative of a hydrocarbon, or a mixture thereof. The reforming medium container 104 stores a reforming medium, such as water. A flow of the hydrocarbon compound from the hydrocarbon container 102 may be regulated by a first control valve 112. Similarly, a flow of the reforming medium is regulated by a second control valve 114. It may be understood that the first control valve 112 and the second control valve 114 may have same or different configurations.

Further, the hydrocarbon compound from the hydrocarbon container 102 and the reforming medium from the reforming medium container 104 flow into a duct 116 to form a mixture. The duct 116 provides a fluid communication between the various components of the system 100. Further, the mixture of the hydrocarbon compound and the reforming medium is carried to the pump 106 through the duct 116. In one embodiment, a flow regulating valve 118 may be provided in the duct 116 to regulate the flow of the mixture to the pump 106. In addition, the flow regulating valve 118 may facilitate effective mixing of the hydrocarbon compound and the reforming medium.

The pump 106 may be a high pressure pump and may pressurize the mixture to a high pressure, for example, the critical pressure of the reforming medium. In one example, when the reforming medium in the mixture is water, the pump 106 may pressurize the mixture to a pressure of about 220 Bar. From the pump 106, the mixture of the hydrocarbon compound and the reforming medium is supplied to the reactor 108 via the duct 116.

In one embodiment, the reactor 108 includes a reforming reactor (not shown in figure). In one embodiment, the reforming reactor has a plurality of tubular passages for flow of the mixture of the hydrocarbon compound and the reforming medium. According to an aspect of the present subject matter, the reforming reactor may further include one or more heat inlets 120. The heat inlet 120 is coupled to an engine (not shown in the figure) of the vehicle and allows the heat from the engine to flow into the reforming reactor. In an implementation, the heat inlet 120 may provide heat of exhaust gases that are emitted by the engine. In another implementation, the heat inlet 120 may provide the heat of a cylinder head of the engine. The cylinder head may absorb the heat of combustion inside a combustion chamber of the engine and that heat may be transferred to the heat inlet 120. Further, the unused heat from the reactor 108 may be expelled through a heat outlet 122.

In one embodiment, the reforming reactor, the heat inlet 120, and the heat outlet 122 may together form an indirect heat exchanger, in which the fluids exchange heat but do not come in contact with each other. The hydrocarbon compound and the reforming medium utilize the heat of the exhaust gases or the cylinder head to attain a temperature of about 600 °C. At such high temperature, the hydrocarbon compound, such as Methyl alcohol, and the reforming medium in the mixture, under the high pressure, react to produce hydrogen (H2) by a reformation reaction. During the reformation reaction, carbon dioxide (CO2) is produced as a by-product. The reaction is depicted by the following exemplary equation:

In another implementation, a hydrocarbon compound such as natural gas reacts with the reforming medium at high temperature to produce the hydrogen. In such a case, carbon monoxide (CO) is produced as a by-product of the reformation reaction. The reaction is depicted by the following general equation:

In one embodiment, the reactor 108 may also include a secondary reactor (not shown in figure) along with the reforming reactor to recover additional hydrogen. In said embodiment, the by-product, i.e., carbon monoxide, from the reforming reactor may be used in the secondary reactor to further produce hydrogen. In one example, the carbon monoxide is reacted with water to produce hydrogen according to a low-temperature gas-shift reaction. The low-temperature gas-shift reaction is represented by the following exemplary equation:

Hence, the secondary reactor increases the yield of the hydrogen produced by the reforming reactor of the system 100. In one implementation, the carbon monoxide from the reactor 108 may heat the water to the required temperature for the reaction. In another implementation, the energy for heating the water to the required temperature is provided by the exhaust gases.

The output from the reactor 108 may be passed into the separator 110 through the duct 116. The output may have, along with hydrogen and carbon dioxide, small quantities of carbon monoxide, the reforming medium, and the hydrocarbon compound. The separator 110 separates the hydrogen from the rest of the constituents of the output. In one implementation, the separator 110 may separate hydrogen from the output by passing the output over a metal or a compound such as Boron (Borax), so that the hydrogen may react to form a hydride. The hydride thus obtained may be stored and may be used to generate hydrogen by simple methods, for example, by reaction of the hydride with water and capturing the gas produced during the reaction. In another implementation, the separator 110 may have carbon nanotubes that may be used to capture the hydrogen in the output.

In one embodiment, hydrogen is separated in the separator 110, and the separated hydrogen may be stored in a hydrogen accumulator 124. The hydrogen accumulator 124 may be formed of an alloy of metals including titanium, manganese, nickel, and chromium. The hydrogen from the hydrogen accumulator 124 is subsequently supplied as a fuel to the engine of the vehicle (indicated in Fig. 1). In an implementation, the hydrogen produced from the system 100 may be used as a supplementary fuel for the vehicle. For example, the hydrogen is used to supplement about 30% of the energy required for the propulsion of the vehicle. In another implementation, the hydrogen may be used as fuel in a fuel cell vehicle, such as a hydrogen fuel cell vehicle, to propel the fuel cell vehicle. In another embodiment, the system 100 may directly supply the hydrogen from the separator 110 to the engine of the vehicle or the fuel cell of the fuel cell vehicle.

Furthermore, the reforming medium and the hydrocarbon compound separated in the separator 110 are again fed to the reactor 108 through a channel 126. An auxiliary pump 128 is provided in the channel 126 to pressurize the reforming medium and the hydrocarbon compound before they are again fed into the reactor 108. The reforming medium and the hydrocarbon compound may not require heating because they are already at the temperature that is required for the reformation reaction to take place.

According to an aspect of the present subject matter, the waste heat of the output from the reactor 108 is also recovered through a return duct 130 and used to heat the mixture of the hydrocarbon compound and the reforming medium in the duct 116.

Fig. 2(a) to Fig. 2(c) illustrate various embodiments of the system 100 for producing hydrogen on-board a vehicle.

Fig. 2(a) illustrates the reactor 108 implemented with an engine 202 of a vehicle, according to an embodiment of the present subject matter. In said embodiment, the reactor 108 is mounted on an exhaust port 204 of the engine 202. Further, in an embodiment, the reactor 108 may be made of Inconel alloy because of its suitability for high temperature applications. However, it may be understood that any other suitable material may be used for making the reactor 108.

The exhaust gases from the engine 202 are expelled through the exhaust port 204 and the heat from the exhaust gases is supplied into the reactor 108 through the heat inlet 120. Inside the reactor 108, the mixture of the hydrocarbon compound and the reforming medium extracts heat from the exhaust gases to attain the required temperature for the reformation reaction. Thereafter, the cooled exhaust gases are carried out of the reactor 108 and the unused heat of the exhaust gases is expelled through the heat outlet 122.

In another embodiment, a metal insert (not shown in the figure) may be provided on the exhaust port 204 to retain the heat to be transferred to the reactor 108.

Fig. 2(b) illustrates the reactor 108 as enmoulded in a cylinder head 206 of the engine 202 of the vehicle. In one implementation, the reactor 108 is end-casted along with the cylinder head 206 of the engine 202, such that the mixture of the hydrocarbon compound and the reforming medium is heated by the heat of combustion of the fuel inside a combustion chamber (not shown in the figure) of the engine 202. In said implementation, the mixture is heated by the heat of combustion absorbed by the cylinder head 206. In another implementation, the reactor 108 may also be heated by the waste heat of the exhaust gases of the engine 202 absorbed by the cylinder head 206.

Fig, 2(c) illustrates the reactor 108 implemented inside a catalytic converter 208. The catalytic converter 208 is provided with the engine 202 to reduce pollutants in the exhaust gases emitted by the engine 202. In one embodiment, the reactor 108 is disposed inside the catalytic converter 208, so that the mixture of the hydrocarbon compound and the reforming medium may be heated to the required temperature for the reformation reaction, and hence to produce hydrogen. With the usage of the catalytic converter 208, a dual purpose of reduction of pollutants in the exhaust gases and the utilization of waste heat from the exhaust gases is achieved.

In said embodiment, the catalytic converter 208 containing the reactor 108 may be disposed near the exhaust port 204 of the engine 202. Further, the catalytic converter 208 may include a close coupled catalyst for the purpose of reducing pollutants in the exhaust gases. In another embodiment, the catalytic converter 208 may be disposed on an exhaust pipe of the vehicle. In said embodiment, the catalytic converter 208, and the reactor 108 therein, is placed close to the exhaust port 204. For example, the catalytic converter 208 containing the reactor 108 may be placed at about 150 mm from the exhaust port 204 on the exhaust pipe.

The previously described versions of the subject matter and its equivalent thereof have many advantages. The system utilizes the waste heat of the exhaust gases to heat the mixture of the hydrocarbon compound and the reforming medium for the reformation reaction, and hence to produce hydrogen. Such a system does not require external heat sources, such as heater coils and glow plugs, and hence, does not require any external power source to operate the heat sources. Therefore, the system described herein can be used for the production of hydrogen as a fuel on-board a vehicle.

Although the subject matter has been described in considerable detail with reference to certain embodiments thereof, other embodiments are possible.

I/We Claim:

1. A system (100) for producing hydrogen on board a vehicle, the system (100) comprising:

a hydrocarbon container (102) mounted on the vehicle to store a hydrocarbon compound;

a reforming medium container (104) mounted on the vehicle to store a reforming medium, wherein the reforming medium container (104) is connected to the hydrocarbon container (102); and

a reactor (108) connected to the hydrocarbon container (102) and to the reforming medium container (104) to receive the hydrocarbon compound and the reforming medium, respectively, wherein the reactor (108) is mounted on the vehicle and coupled to an internal combustion engine (202) of the vehicle to obtain heat for reforming the hydrocarbon compound in presence of the reforming medium and for producing hydrogen.

2. The system (100) as claimed in claim 1, wherein the reactor (108) comprises a reforming reactor to reform the hydrocarbon compound in presence of the reforming medium to produce the hydrogen.

3. The system (100) as claimed in claim 2, wherein the reactor (108) further comprises a secondary reactor coupled to the reforming reactor, wherein the secondary reactor is configured to produce the hydrogen from by-products obtained from the reforming reactor.

4. The system (100) as claimed in claim 1, wherein the reforming medium container (104) and the hydrocarbon container (102) are connected to the reactor (108) through:

a flow regulating valve (118) to substantially mix the hydrocarbon compound and the reforming medium; and

a pump (106) to pressurize the substantially mixed hydrocarbon compound and the reforming medium.

5. The system (100) as claimed in claim 1, wherein the reactor (108) is disposed on an exhaust port (204) of the internal combustion engine (202) to extract the heat from exhaust gases.

6. The system (100) as claimed in claim 1, wherein the reactor (108) is disposed in a cylinder head (206) of the internal combustion engine (202) to obtain the heat absorbed by the cylinder head (206).

7. The system (100) as claimed in claim 1, wherein the reactor (108) is disposed in a catalytic converter (208) coupled to the internal combustion engine (202), and wherein the reactor (108) obtains the heat from exhaust gases passing through the catalytic converter (208).

8. The system (100) as claimed in claim 7, wherein the reactor (108) is disposed in the catalytic converter (208) positioned in proximity to an exhaust port (204) of the internal combustion engine (202).

9. The system (100) as claimed in claim 7, wherein the reactor (108) is disposed in the catalytic converter (208) positioned on an exhaust pipe of the internal combustion engine (202) at a distance of about 150 millimeters from an exhaust port (204) of the internal combustion engine (202).

10. The system (100) as claimed in claim 1 further comprising:

a separator (110) coupled to the reactor (108), wherein the separator (110) is configured to receive an output from the reactor (108) and to separate the hydrogen from other constituents in the output; and

a hydrogen accumulator (124) to store the separated hydrogen obtained from the separator (110).