US20070089997A1

US20070089997A1 - Method and apparatus for the production of hydrogen and oxygen

Info

Publication number: US20070089997A1
Application number: US11/254,593
Authority: US
Inventors: Robert Depalo
Original assignee: World Energy Solutions Inc
Current assignee: World Energy Solutions Inc
Priority date: 2005-10-20
Filing date: 2005-10-20
Publication date: 2007-04-26

Abstract

A method and apparatus for producing hydrogen and oxygen gas includes a tank for capturing the gas and holding anodes and cathodes submersed in water. An electrical supply is attached to the anodes and cathodes, providing direct current modulated at a duty cycle that is varied depending on the measured pressure of the produced gas.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention
The present invention relates to the field of generating a hydrogen and oxygen gasses using electricity and more particularly to an apparatus and method that produces the gasses in an efficient manner while permitting continuous control of gas production.
2. Description of the Related Art
Using electricity to decompose water into hydrogen and oxygen gas was discovered by William Nicholson in 1800. The process uses two electrodes, a cathode and an anode, immersed in water (not pure water). The electrodes are coupled to a direct current power source, the cathode to the negative power source and the anode to the positive power source. As current passes through the water, hydrogen is produced around the cathode and oxygen around the anode. The gasses may be left separate or allowed to mix, the mixed gasses often known as “Brown's gas,” hereby referred to as “brown gas.” Burning the brown gas produces an intense heat that can be used in welding, to heat buildings, or heat water. pollution and no negative health effects. During the burning of brown gas, heat and water are produced and virtually no pollutants, thereby allowing burning within occupied spaces without consuming air during the burning process and without the need for an exhaust. There are no known health issues with brown gas, in that handling the gas, a gas leak or exhausts from the burning process don't include CO or CO₂or any other gas that will cause suffocation. Furthermore, because brown gas is lighter than air, any leakage will dissipate into the air, whereas other commonly used gasses such as propane are heavier than air, collect at ground level and can be inadvertently ignited. On the negative side, Hydrogen gas and brown gas are volatile and proper precautions must be taken to prevent explosion.
Current electrolysis techniques use a low-voltage, direct current passing through electrodes immersed in water (a mild acid may be added to increase current flow). Currently, tens to hundreds of ampere are required to produce brown gas in significant volume, requiring around 4 kWh of power to produce 1000 L of hydrogen. It has been measured that 1L of water produces 1234 L of hydrogen and 605 L of oxygen. Being that ⅔s of the earth's surface is covered with water; an almost limitless supply of brown gas (or hydrogen) is available given sufficient electrical input. It can be seen that the production of brown gas through electrolysis creates a greater volume of brown gas than the water used in the conversion process, hence, the as the process continues in a confined space, the brown gas becomes pressurized.
There is a need for using brown gas in a commercial embodiment. U.S. Pat No. 2,098,629, “Production of Gas and Combustion Thereof,” to Knowlton, describes a method of generating brown gas and burning the gas to heat water and is hereby incorporated by reference. This patent uses DC power derived by rectifying AC power using a full-wave bridge rectifier. In this, production of gas is regulated by mechanically monitoring the gas pressure and halting electrolysis by disconnecting the DC power source when the pressure exceeds a predetermined threshold set by a spring.
Unfortunately, the amount of electricity required for generating brown gas and the ability to discretely control the production of the gas in response to demands limits the efficiency of prior systems.
What is needed is a method and apparatus that will efficiently produce Brown gas with a robust control to modulate production to match consumption.

SUMMARY OF THE INVENTION

In one embodiment, an apparatus for producing brown gas is disclosed including a sealed tank with an exit for extracting the brown gas and a source of modulated direct current with a positive and a negative output; the source can vary the duty cycle of the outputs. At least one anode within the sealed tank is connected through an opening to the positive output and at least one cathode within the sealed tank is connected through a second opening to the negative output and both are at least partially immersed in water. A pressure sensor is coupled to the sealed tank for measuring a pressure of the brown gas and is connected to the source of modulated direct current. The source of modulated direct current changes the duty cycle of the outputs in response to changes in the pressure.
In another embodiment, a method of producing brown gas is disclosed including providing a sealed tank with an exit for extracting the brown gas and a source of modulated direct current with a positive and a negative output; the source is able to vary a duty cycle of its outputs. At least one anode is provided within the sealed tank and is connected through an opening in the sealed tank to the positive output of the source of modulated direct current. At least one cathode is provided within the sealed tank and is connected through a second opening in the sealed tank to the negative output of the source of modulated direct current. The at least one anode and at least one cathode are immersed in water. The pressure of the brown gas is measured and the duty cycle of the outputs are changed in response to changes in pressure.
In another embodiment, a means for producing brown gas is disclosed including a tank with an exit for extracting the brown gas and a direct current modulator having a positive output and a negative output. The modulator has a way to vary the duty cycle of the outputs. There is at least one anode within the tank connected through an opening to the positive output of the direct current modulator and at least one cathode within the tank connected through a second opening in the tank to the negative output of the direct current modulator. The anodes and cathodes are at least partially immersed in water. There is a pressure sensor coupled through an opening in the tank and connected to the direct current modulator for measuring the pressure of the brown gas. The direct current modulator changes the duty cycle of the outputs in response to the pressure.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention can be best understood by those having ordinary skill in the art by reference to the following detailed description when considered in conjunction with the accompanying drawings in which:
FIG. 1 illustrates a schematic view of the apparatus of the present invention.
FIG. 2 illustrates a plan view of the present invention.
FIG. 3 a-FIG. 3 c illustrates power delivery waveforms of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to the presently preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. Throughout the following detailed description, the same reference numerals refer to the same elements in all figures. Throughout this specification, the term “brown gas” is used to describe the mixture of hydrogen (H₂) and oxygen (O₂) generated through the electrolysis of water. Brown gas is not limited to only hydrogen and oxygen, in that other impurities may exist in the gas without veering from the present invention. Furthermore, the same process and same system works equally well to generate oxygen (O₂) and hydrogen (H₂) and each may be stored separately and combined later as needed. Throughout this specification, the term water refers to water (H₂O) with minerals and/or salts such as ordinary tap water, which is a conductor of electricity. Pure water cannot be used because it is an insulator and electricity would not flow and electrolysis would not occur.
Referring to FIG. 1, a schematic of the apparatus of the present invention is shown. Although showing an alternating current power source 10, the present invention works equally well with a direct current (DC) power source. The source power 10 is rectified by a rectifier 12. Shown is a full-wave bridge rectifier 12, though any suitable rectifier configuration works equally as well. The DC output 14 of the rectifier 12 is connected to a duty cycle and frequency modulator and high current driver 16 that modulates the DC voltage, and hence output current. The duty cycle and frequency modulator and high current driver 16 has an input from 22 from the pressure sensor 36 that is used to adjust the duty cycle in response to pressure changes as will be explained later. High current drivers 16 are known in the industry an example of which is a high-current power MOSFETs, silicon controlled rectifiers (SCRs), Triacs or other transistor or multiples of such configured in a parallel fashion, or any other type of high current amplifier including a fast-acting relay. Although, as shown, the AC power is converted to DC power by the rectifier 12, then the DC power is modulated, there are other ways to modulate the duty cycle that work equally as well. Because of the high current and low voltage required, a step-down transformer (not shown) is often required. In an alternate embodiment, the duty cycle of the AC input to the step-down transformer is controlled using an SCR or Triac, in much the same way as a light dimmer operates. The low-voltage output of the transformer is rectified, resulting in a low-voltage, high-current variable pulse-width DC current.
The positive output 24 of the high current driver 16 is connected to a series of anodes 32 that are submerged in a tank 31 of water (not pure water). The negative output 26 of the high current driver 16 is connected to a series of cathodes 34, also submerged in water within the tank 31 and alternately intermixed within the tank 31, so as to provide a high amount of surface area to provide lower impedance to the flow of electricity between the cathodes 34 and the anodes 32.
The area above the water level 30 allows for the collection of brown gas as current flows between the cathodes 34 and the anodes 32. A valve 40 controls the flow of brown gas out of the tank 31 through a pipe or tube 42. Not shown are various protection devices to prevent back flashes from reaching the tank 31, potentially causing an explosion. A pressure sensor 36 monitors the pressure in the tank 31 and is coupled to the duty cycle and frequency modulator and high current driver 16 through signal path 22. The duty cycle and frequency modulator and high current driver 16 reduces the duty cycle as the pressure increases, thereby limiting the gas pressure. Alternately, the duty cycle and frequency modulator and high current driver 16 increases the duty cycle as the pressure decreases, thereby supplying the needed gas pressure.
To understand the closed-loop operation of the system, assume the gas output 42 is connected to a hot-water heater (not shown). When the system is first started, no brown gas is present in the tank 31; therefore the pressure measured by the pressure sensor 36 is zero (roughly atmospheric pressure). When power is applied, the duty cycle and frequency modulator and high current driver 16 determines that there is no gas pressure and delivers power as in the waveform in FIG. 3 c, thereby producing brown gas at a high-volume output. As the pressure increases, the gas pressure sensor 36 relays this to the duty cycle and frequency modulator and high current driver 16 and a waveform with a 50% duty cycle (as in FIG. 3 b) is generated, thereby producing a medium amount of brown gas. When the gas pressure reaches a high level, the duty cycle and frequency modulator and high current driver 16 delivers a waveform with a low duty cycle (as in FIG. 3 a), thereby producing a very small amount of brown gas without stopping the reaction within the water. When the water heater requires gas, for example when water is being used, the valve 40 opens and gas flows from the tank 31 to the water heater, thereby reducing the gas pressure. As the sensor measures a lower pressure, the duty cycle and frequency modulator and high current driver 16 increases the duty cycle delivered to the anodes 34 and cathodes 32, thereby increasing the production of brown gas. Therefore, only a small amount of brown gas is stored in the tank 31 and when needed, the duty cycle is increased causing production of brown gas to increase.
The relative gas production is charted against the duty cycle of the frequency modulator in Chart 1. The measurements in Chart 1 were taken using a 100 SCFH flow meter. The frequency modulator uses a full-wave rectifier producing unfiltered direct current of 120 pulses per second having an approximate period of 8.3 ms. The duty cycle is varied by delaying the application of power to the plates of the electrolyzer during each pulse by ⅛, 2/8, ⅜, 4/8, ⅝, 6/8, ⅞ and 8/8, thereby generating duty cycles of 0, 12.5%, 25%, 37.5%, 50%, 62.5%, 75%, 87.5% and 100%. It can be seen in the chart that the gas production varies proportionately with the duty cycle. It can also be seen that the measured data (solid line) is substantially greater than the linear production (dashed line), showing the gas production is more efficient using pulsed direct current rather than using direct current. For example, at a 75% duty cycle, the measured gas production is 96% of the maximum, in that, reducing power input to the system to 75% yields gas production of 96% instead of 75%, producing much higher efficiencies than a system using direct current only. It should be noted that the first two data points of the measured data (0.125 and 0.25) are estimated because the gas production is too slow to accurately measure.
Referring to FIG. 2 a plan view of the present invention is shown. The tank 80 is filled with water to a level 86 high enough to at least partially cover the anodes 32 and cathodes 34. A pipe or tube 43 provides a path for the brown gas to be transported to an appliance such as a heater or water heater. In practice, several safety systems (not shown) are attached to the pipe 43 before reaching the appliance to reduce the chances of a back flash reaching the tank 80 and causing an explosion. The top edge of the tank 80 has a flat surface with holes or threads 84 for attaching to the cover 90 through matching holes 94 (the fasteners are not shown for clarity purposes but can be any known in the industry). On the cover 90, two holes 96 are provided to pass electricity into the electrolysis process. In embodiments where the cover 90 is made from a conductive material, insulators 97 are deployed between the positive 24 and negative 26 terminals of the electrolysis grid and the cover 90. Each cathode 34 is connected to the negative terminal by a buss 27 and each anode 32 is connected to the positive terminal 24 by a second buss 25. At the opposite end of each anode 32 and cathode 34 are insulating spacers 39 that keep the ends from getting too close and shorting against each other. Although two pairs of anodes 32 and cathodes 34 are shown, any number and any size is possible depending upon the brown gas output rate desired. Increasing the surface area of the anodes 32 and cathodes 34, or spacing them closer or increasing their quantity reduces the impedance of the electrolysis grid, allowing higher current and, hence, higher production of brown gas. A pressure sensor/transducer 104 is connected through a pipe 88 into the tank 80 at a point above the water level 86 so gas pressure can be measured and transferred to the duty cycle and frequency modulator and high current driver 102 through wires 105. In one embodiment, AC power is supplied to the duty cycle and frequency modulator and high current driver 102 by AC power cable 100. The modulated DC output from the duty cycle and frequency modulator and high current driver 102 is delivered on a negative conductor 106 that connects to the cathodes 34 through the negative terminal 26 and a positive conductor 108 connecting to the anodes 32 through the positive terminal 24.
Equivalent elements can be substituted for the ones set forth above such that they perform in substantially the same manner in substantially the same way for achieving substantially the same result.
It is believed that the system and method of the present invention and many of its attendant advantages will be understood by the foregoing description. It is also believed that it will be apparent that various changes may be made in the form, construction and arrangement of the components thereof without departing from the scope and spirit of the invention or without sacrificing all of its material advantages. The form herein before described being merely exemplary and explanatory embodiment thereof. It is the intention of the following claims to encompass and include such changes.

Claims

1. An apparatus for producing brown gas, the apparatus comprising:

a sealed tank having an exit for extracting the brown gas;

a source of modulated direct current having a positive output and a negative output, whereas the source of modulated direct current can vary a duty cycle of the outputs;

at least one anode within the sealed tank, the at least one anode connected through a first opening in the sealed tank to the positive output of the source of modulated direct current;

at least one cathode within the sealed tank, the at least one cathode connected through a second opening in the sealed tank to the negative output of the source of modulated direct current, the at least one anode and at least one cathode are at least partially immersed in water; and

a pressure sensor coupled through a third opening to the sealed tank for measuring a pressure of the brown gas within the sealed tank and connected to the source of modulated direct current; whereas the source of modulated direct current changes the duty cycle of the outputs in response to the pressure.

2. The apparatus of claim 1, wherein the water comprises H₂O and at least one compound selected from the group consisting of minerals and salts.

3. The apparatus of claim 1, wherein the water includes a mild acid to improve conduction.

4. The apparatus of claim 1, wherein the source of modulated direct current includes a source of alternating current coupled to a rectifier, the rectifier producing direct current that is modulated by a high current driver.

5. The apparatus of claim 1, wherein the source of modulated direct current decreases the duty cycle in response to increases in the pressure.

6. The apparatus of claim 1, wherein the source of modulated direct current increases the duty cycle in response to decreases in the pressure.

7. The apparatus of claim 1, wherein the at least one anode and at least one cathode are alternately positioned substantially in parallel to each other within the sealed tank.

8. The apparatus of claim 7, wherein the at least one anodes are connected at a first anode end by a positive buss and the at least one cathodes are connected at a first cathode end by a negative buss.

9. The apparatus of claim 8, wherein a plurality of insulators are affixed to the anodes at an end distal to the first anode end and to the cathodes at an end distal to the first cathode end.

10. A method for producing brown gas comprising:

providing a sealed tank having an exit for extracting the brown gas;

providing a source of modulated direct current having a positive output and a negative output, whereas the source of modulated direct current can vary a duty cycle of the outputs;

providing at least one anode within the sealed tank, the at least one anode connected through a first opening in the sealed tank to the positive output of the source of modulated direct current;

providing at least one cathode within the sealed tank, the at least one cathode connected through a second opening in the sealed tank to the negative output of the source of modulated direct current;

immersing the at least one anode and at least one cathode in water within the sealed tank;

measuring a pressure of the brown gas in the sealed tank; and

changing the duty cycle in response to changes in pressure.

11. The method of claim 10, wherein the water comprises H₂O and at least one compound selected from the group consisting of minerals and salts.

12. The method of claim 10, wherein the water includes a mild acid to improve conduction.

13. The method of claim 10, wherein the source of modulated direct current includes a source of alternating current coupled to a rectifier, the rectifier producing direct current that is modulated by a high current driver.

14. The method of claim 10, wherein the source of modulated direct current decreases the duty cycle in response to increases in the pressure.

15. The method of claim 10, wherein the source of modulated direct current increases the duty cycle in response to decreases in the pressure.

16. The method of claim 10, wherein the at least one anode and at least one cathode are alternately positioned substantially in parallel to each other within the sealed tank.

17. The method of claim 16, wherein the at least one anodes are connected at a first anode end by positive buss and the at least one cathodes are connected at a first cathode end by a negative buss.

18. The method of claim 17, wherein a plurality of insulators are affixed to the anodes at an end distal to the first anode end and to the cathodes at an end distal to the first cathode end.

19. An means for producing brown gas, the means comprising:

a tank means having an exit for extracting the brown gas;

a direct current modulator means having a positive output and a negative output, whereas the direct current modulator means has a means to vary a duty cycle of the outputs;

at least one anode within the tank means, the at least one anode connected through a first opening in the tank means to the positive output of the direct current modulator means;

at least one cathode within the tank means, the at least one cathode connected through a second opening in the tank means to the negative output of the direct current modulator means, the at least one anode and at least one cathode are at least partially immersed in water; and

a pressure sensor means coupled through the tank means for measuring a pressure of the brown gas and connected to the direct current modulator; whereas the direct current modulator means changes the duty cycle of the outputs in response to the pressure.

20. The means of claim 19, wherein the water comprises H₂O and at least one compound selected from the group consisting of minerals and salts.

21. The means of claim 19, wherein the water includes a mild acid to improve conduction.

22. The means of claim 19, wherein the direct current modulator means includes a source of alternating current coupled to a rectifier, the rectifier producing direct current that is modulated by a high current driver.

23. The means of claim 19, wherein the direct current modulator means includes a source of alternating current that is modulated by a high current driver and coupled to a rectifier.

24. The means of claim 19, wherein the direct current modulator decreases the duty cycle in response to increases in the pressure.

25. The means of claim 19, wherein the direct current modulator increases the duty cycle in response to decreases in the pressure.

26. The means of claim 19, wherein the at least one anode and at least one cathode are alternately positioned substantially in parallel to each other within the tank means.

27. The means of claim 26, wherein the at least one anode are connected at a first anodes end by positive buss and the at least one cathodes are connected at a first cathode end by a negative buss.

28. The means of claim 27, wherein a plurality of insulators are affixed to the anodes at an end distal to the first anode end and to the cathodes at an end distal to the first cathode end.