Oxyhydrogen Generator Development

The Question

• Given that on-demand hydrogen can be generated anywhere, why is it so unpopular for on-demand generation of cutting gas? The big guys [1] say that is expensive.

However, if a 50 lb bottle of acetylene is $100 - and electricity is 10 cents per kilowatt hour - we have $100 would cover 1000 hours of such cutting. Assuming that it takes 5kW to generate a cutting flame at 85% electrolyzer efficiency - that is enough for 200 hours of cutting on the equivalent of one tank of acetylene. One tank of acetylene lasts no more than 24 hours in cutting, so oxyhydrogen appears to be a factor of 10 cheaper. See supporting reference - [2]

Why nobody oxyhydrogen cuts?

Arguments For

• Can also cut aluminum and stainless steel - [3]
• Cost comparison - more than 2x as cheap as acetylene- see chart at [4]
• "As you know when it comes to oxy-fuel applications the "Holy Grail" is Hydrogen - See more at: http://www.harrisproductsgroup.com/en/Expert-Advice/Articles/Oxy-Hydrogen.aspx#sthash.1fs1Ja4y.dpuf "
• Welding Engineer, p. 31 - oxyhydrogen cutting is significantly faster (2x) than oxyacetylene - for large cuts. [5]
• Welding Engineer, p. 39 - acetylene takes significantly more oxygen to burn than oxyhydrogen. This appears to make the economic advantage of oxyhydrogen more than 10x that of oxyacetylene
• A practical guide of Autogenous Welding - p. 214 - oxyhydrogen is as good if not better for cutting than oxy-acetylene. [6]
• This one says oxyhydrogen and oxyacetylene consumption of oxygen are the same - p. 223 of [7]
• Temperature of burn (6000F) [8] even higher than oxyacetylene (5400F)

Against

• It works well, but is expensive - [9]
• "Inferior to acetylene" apparently on flame temperature - see below Fig. 4 at [10]
• For welding applications, poor because water vapor produced oxidizes welds - p. 22 - [11]

Sources

• 95L per hour - $200 - [12]
• 360L/hr - $150 - [13]
• 600L per hour - $1700 - [14]
• 100 gallon/hr - Aquygen 1500 - [15]
• Hydrogen cutting torches - [16]
• Water torches in jewelry -[17]
• Aquatorch - Kearny, NJ - http://www.lrultrasonics.com/press/press01.html
• .6 l water consumption/hr = 30 moles of water turned to 60 moles of gas - [18]. More like 1000l gas per hour?

Consultants

• http://www.welding-advisers.com/contact.html

Calculations

• 3000l/hr cuts up to 80 mm steel and takes 9kW of electricity - [19]. If this costs $1/hour - this is quite inexpensive for fuel.
• 1000l/hr, 3.6 kW - $5k - [20]
• It takes 3kWhr/ cubic meter of hydrogen (and 0.5 cubic meter of oxygen) if efficiency of hydrogen generation were 100% - from Solar Hydrogen Chronicles.
• The Solar Hydrogen Chronicles system is 12 cells for 1kW total, producing 170 liters of hydrogen per hour, 85 liters of oxygen per hour.
• 500 gallon propane tank - 2000 liters - if stored at atmospheric pressure - would give 40 minutes of cutting of 3" thick steel. For 1/2" steel, that would probably be 2 hours of cutting. If stored at 8.6 bar - could provide all day of cutting.
• Hydrocue uses 4 l/min of hydrogen.

Jewelry HHO Torch DIY

• Good explanatory DIY torch video - [21]

Patents

• Seminal patent for oxyhydrogen production - [22]
• Oxyhydrogen torch patent - 1917 - [23]
• Oxyhydrogen cutting torch patent, 1920 - [24]

History

• Harris claims to have invented oxy-acetylene cutting in 1899 - [25]

Links

• Oxyhydrogen Cutting
• King of Random Oxyhydrogen Generator.