Converting conventional stove top burners to run on hydrogen is

a simple process. Knowing the proper handling procedures of

hydrogen will make your installation safe and efficient.

 

Much of the research that I refer to in this article was

performed by Roger Billings, N. R. Baker, and their associates of

the now defunct Billings Energy Corporation. This pioneering

work was done mostly in the 1970s. An early research endeavor

involved conversion of all the gas appliances on a Winnebago

recreational vehicle from propane to hydrogen operation. To

demonstrate hydrogen's practicality even further, five natural

gas appliances were converted to hydrogen. This multi-phased

project in Provo, Utah was called the Hydrogen Homestead.

 

Included among the appliances converted for this home were an

oven, a range, a barbeque, a fireplace log burner, and the

booster heater for the home's heat pump system.

 

Theory before Practice

 

Hydrogen burns differently than either propane or natural gas.

In particular, hydrogen's rate of diffusion and flame velocity

are roughly ten times or greater that of propane or natural gas.

Diffusion rate measures how long it takes a gas introduced in

one side of a room to be detected on the other side. Flame speed

is how fast a flame grows to burn available fuel.

 

Flashback of the flame into the primary mixture of fuel gas and

air must be prevented in all burners. This is typically achieved

with natural gas and propane by adjusting the fuel velocity so

that it is higher than the normal flame velocity. The flame

velocity of hydrogen is too high for this technique to be

practical. Another flashback control strategy employs burner

ports with a minimum quenching diameter which theoretically

will not allow the flame to pass back through the port. In

practice, however, it is very difficult to make the holes small

enough to quench a hydrogen flame. Fortunately, flashback can

be minimized by preventing hydrogen from mixing with air

before the burner port. Some flashback may still occur creating

a loud popping sound but this noise is usually harmless.

 

Burners optimized for hydrogen combustion require that

undiluted hydrogen be delivered directly to the burner ports

without primary or secondary air mixing. So, if we are trying to

work with an existing burner in a typical gas appliance, we will

have to find a suitable method to seal off any openings that

were installed for this purpose. One method won't work in all

instances. We used silicon sealant with stainless steel tape

and ring clamps in one recent alteration, but this simple

Coleman stove conversion hasn't been subjected to long term

use as yet. The actual openings we are referring to may be an

integral part of a cast iron body. Or the primary air openings

may be a modest distance from the burner head in an aluminum

delivery tube with an adjustable closure.

 

From scratch

 

It is not inconceivable that one might rather opt to build a

simple burner and direct fuel delivery apparatus from the

ground up, rather than deal with the problem of sealing off a

nagging assortment of useless holes. Burners and their attached

parts get hot, and transfer heat readily through conduction.

Sorry, duct tape and chewing gum won't cut it.

 

Our first attempt at a simple hydrogen conversion utilized a

rudimentary two burner range of cast iron construction. After

we tossed the existing burner assembly, and removed the

screwed on brass orifice, a threaded adaptor was exposed. To

this we screwed on a 1/4 inch straight coupling followed by a

short length of black iron pipe of the same diameter. Don't use

galvanized pipe, because of the fumes that will be released at

high temperatures. Then we installed a 90 degree elbow

followed by a short vertical nipple of more pipe. Next a 1/4

inch fitting shaped like a cross with four female threaded

openings was drilled and tapped to create a fifth hole. This

threaded onto the short vertical nipple, and four slightly longer

nipples of equal length extended out radially from the

remaining holes. Finally, these terminated in threaded end caps.

A drill press is almost essential for drilling a series of very

fine holes which will line up along the top of the radial burner

arms, and through the top of the cross. Ideally, these burner

ports would have a 0.0225 inch (0.057 cm) diameter or less,

which is the minimum quenching diameter.

 

The catalytic advantage

 

It has been observed in early experiments that the flame

combustion of hydrogen/air mixtures can lead to unacceptable

levels of nitrogen oxide (NOx) pollutant emissions. The primary

end product of hydrogen combustion is simply water vapor.

However, if the temperature of combustion exceeds the

threshold level of 2400øF (1315øC.), a significant amount of

oxygen and nitrogen from the air may react and form this

unwanted byproduct. This also occurs with natural gas

(primarily methane), propane, and other hydrocarbon fuel

combustion.

 

Fortunately, you can use a catalyst to lower the combustion

temperature thus preventing the formation of nitrogen oxides.

The catalytic material is not used up or altered in any fashion

in the process.

 

There are two catalytic conversion techniques which succeed in

producing negligible levels of NOx emissions. The first

approach uses experience gained by Billings and his associates

with flame assisted catalytic burners. Their conversions

utilized the catalytic properties of stainless steel at elevated

temperatures. Later, in another article, we'll describe the

conversion of a catalytic space heater which optimizes

"flameless" combustion with a small amount of platinum.

 

Flame assisted catalysis

 

The technique developed by the Billing's research team to

reduce NOx formation relies on controlling two interacting

phenomena. First, as has already been described, hydrogen/air

mixing is inhibited by blocking off any primary air openings.

Second, a stainless steel wire mesh is arranged tightly around

the circular burner head or radial burner arms.

 

Where does one find stainless steel wool or wire mesh? Look

for stainless steel pot scrubbers in a large, thoroughly stocked

supermarket in the housewares section.

 

Getting our NOx off

 

This stainless steel wool blanket around the burner actually

serves two complimentary functions. It inhibits the mixing of

air and hydrogen thus producing a zone immediately surrounding

the burner head where the concentration of hydrogen is very

high and the concentration of air is very low. The wire mesh

should be thick enough so that the flame does not radiate above

it or out too far laterally. If there isn't a sufficient amount of

stainless steel mesh, the catalytic capability and ability to

negate NOx production could be lost.

 

Stainless steel also works as an excellent catalyst for

hydrogen combustion. Hydrogen and oxygen are thus combined on

the surface of the catalyst at a slower rate than would occur

without the catalyst. This eliminates the high temperatures

that are produced when a large fraction of hydrogen is

combusted in a small area. The result of the lowered

combustion temperature is that nitrogen oxides are virtually

eliminated. The steel wool proceeds to glow bright red even at

these temperatures, indicating that the otherwise invisible

hydrogen flame is present.

 

According to Roger Billings in The Hydrogen World View, flame

assisted catalytic technique can lower NOx emission from

hydrogen combustion in range burners, ovens, and space heaters

to negligible levels. The resulting data showed NOx emission

levels between 1 and 5 parts per million (ppm) for a catalytic

assisted burner. This can be compared with 40 ppm for

conventional range burners operated on natural gas and 250 ppm

for a hydrogen burner without a catalyst.

 

Water vapor is the only byproduct along with heat, so no venting of the

appliance may be necessary (if means to prevent oxygen

depletion for the room air is assured).

 

There may well be a wealth of undiscovered and untapped

hands-on information available from other hydrogen

enthusiasts out there scattered through the countryside. If you

are among the other backyard tinkerers and hydrogen pioneers

who are putting theory into practice, let us hear from you. The

time has come to spread the word about hydrogen's unique

advantages. It is clearly the hands-down winner among the

possible candidates of alternative fuels for the future in our

environmentally beleaguered world.

 

A note on safety

 

Remember that storing pure hydrogen can be regarded as a

relatively safe procedure, but storing hydrogen /air or

hydrogen/oxygen mixtures is foolhardy and strictly inadvisable.

 

Hydrogen is the KEY to ending Energy Cartel control of YOU!                     They don't want you to know about Hydrogen