Most modern HVACR technicians use oxy-acetylene for cutting and welding, as opposed to oxy-hydrogen. But, noxious gases, which result while acetylene burns, do little for the environment.
Acetylene is more highly regarded than other fuel gases for the fact that it produces extremely high temperature flames. Hydrogen, on the other hand, produces hotter flames and equally gets the job done.
With acetylene, the combination most commonly used—oxygen and acetylene—is paired in two separate cylinders. Oxy-hydrogen, in contrast, is simply the burning of pre-mixed H2 and O2.
This article compares and contrasts both hydrogen and acetylene to properly illustrate their benefits and drawbacks. Before starting, let’s first consider how they work.
As indicated above, an oxy-acetylene flame requires a 1.1:1 ratio of pure compressed oxygen to acetylene in two separate cylinders. The acetylene cylinder is compressed with 50% acetone, the soluble form of acetylene, and the rest of porous materials (such as kapok fiber, diatomaceous earth or aka asbestos). The oxygen and acetylene then join together, producing a high intense temperature flame.
Hydrogen is the most abundant substance in the universe. On earth, oxygen is near close to the most abundant, possibly bested or seconded by good old water. The burning of oxygen and hydrogen releases nothing more than water and energy in the form of heat. When combined in a 2:1 ratio, hydrogen and oxygen can produce quite a powerful flame. In the past, hydrogen was more commonly used for underwater cutting and welding applications.
Oxy-Acetylene vs Oxy-Hydrogen Comparisons:
Both gas combinations produce intense flames, but oxy-hydrogen can measure up to 6,000oF, surpassing oxy-acetylene which measures at approximately 5,400oF.
Both applications are quite expensive. Since the process to separate water into two parts—oxygen and hydrogen—requires a lot of energy, the application can cost quite a hefty sum. Oxy-acetylene is similarly expensive, with the cost of both cylinders to account for.
Ease of Use
The use of two cylinders associated with oxy-acetylene can complicate the process. Since the cylinder volumes differ, the draw off can be unequal, thereby resulting in a trip back to your gas provider for additional or backup oxygen cylinders.
Oxy-hydrogen, however, requires only a single apparatus which, in some cases, is where the electrolysis of water takes places. This greatly simplifies its use in comparison to its counterpart.
Both methods come with their fair share of risks. If caution isn’t adhered to, the presence of both oxygen and acetylene can result in a flashback, which is the ignition from mixed gases.
The lack of carbon in the oxy-hydrogen system results in the emission of clear fire. Depending on how brightly lit an area is, this fire may not be easily perceived. Suffice it to say that there are not many things as dangerous as invisible fire.
Also, hydrogen can at times leak due to its consistency. So check thoroughly for leaks, and only use in well ventilated areas.
Unlike oxy-acetylene that releases highly noxious gases, oxy-hydrogen is virtually eco-friendly. As indicated above, oxy-hydrogen releases two harmless by-products—energy in the form of heat and water—making it the system of choice when the objective sought is zero carbon emission.
Both Oxy-Hydrogen and Oxy-Acetylene systems are highly effective in producing high heat flames. Likewise, both have their fair share of risks and drawbacks. However, for the fact that it produces higher heat, that it’s environmentally friendly, and that it’s easier to use, the oxy-hydrogen is far superior to its counterpart.