An acetylene gas generator controls contact between calcium carbide and water to produce acetylene. The animation shows a carbide-to-water arrangement with solid feed, reaction liquid and a gas outlet. Enter charge mass, purity and conversion assumptions to estimate total gas yield and an equivalent consumption time.
Acetylene Gas Generator Interactive Calculator
Vary carbide charge, purity, reaction efficiency, and torch consumption to see acetylene yield and run time.
Equation Used
The calculator converts the charged calcium carbide mass into moles of pure reacting CaC2 using purity and eta, then uses the 1:1 reaction stoichiometry to estimate acetylene volume. Torch run time is the produced gas volume divided by the torch consumption rate.
- Gas volume uses the rounded ideal molar volume 22.4 L/mol at 0°C and 1 atmosphere. Consumption flow must use the same reference conditions.
- Calcium carbide molar mass is 64.1 g/mol.
- One mole of CaC2 produces one mole of C2H2.
- Purity is the assumed CaC2 mass fraction; eta is the fraction of that CaC2 that reacts. These must come from appropriate material and process information, not from the drawing.
Controlled contact produces gas
The reaction is CaC₂ + 2H₂O → C₂H₂ + Ca(OH)₂. It produces acetylene, calcium hydroxide and heat. A generator controls how the reactants meet and manages the gas, liquid and residue that result.
In a carbide-to-water arrangement, a feed system introduces solid carbide into reaction water. In a water-to-carbide arrangement, water reaches a carbide charge. These names describe the contact method, not a universal capacity, pressure or safety rating.
The animation shows feed particles entering the liquid, bubbles in the reaction area and gas leaving at the top. Particle speeds are illustrative. The total-yield equation does not calculate reaction rate, temperature, pressure, mixing or the response when gas demand changes.
Functions in a complete installation
- Feed and reaction vessel: control contact and contain the process.
- Water and temperature management: handle liquid supply and reaction heat.
- Gas treatment: address moisture or impurities as required by the installation.
- Controls and protective devices: manage rated operation and abnormal conditions.
- Residue handling: manage alkaline material and any remaining reactive carbide.
Actual construction and protective arrangements depend on the equipment. The schematic is not a vessel drawing, relief-device specification or operating procedure. Use the manufacturer’s rated system and instructions.
Generating acetylene at the point of supply
Carbide-and-water generation has served gas lighting and industrial acetylene supply. The Science Museum Group’s acetylene-generating plant provides a historical example. Modern industrial equipment, such as the Rexarc ATX generator, includes dedicated feed, water and control systems.
A generator, a gas holder and a dissolved-acetylene cylinder serve different functions. Production creates gas; a holder accommodates inventory; a purpose-built cylinder stores acetylene in its designated system. A total gas quantity does not specify how to contain, compress or deliver it.
The calculator helps compare the effect of charge and material assumptions. It does not establish that a portable generator is suitable for a remote welding job or that carbide is inherently safer to transport than another fuel supply.
Charge yield and equivalent runtime
Let m be charge mass in kg, P the CaC₂ mass fraction and η its reacted fraction. The reacting mass is 1000mPη in grams. With molar mass 64.1 g/mol, the acetylene amount is n = 1000mPη/64.1 mol because the reaction produces one mole of acetylene per mole of carbide.
At the stated reference conditions, volume V = 22.4n liters, or V/1000 m³. The Yield Rate card is V/m in L/kg; despite its label, this is yield per mass, not production per unit time.
For a steady consumption Q in reference m³/h, equivalent runtime is t = (V/1000)/Q hours, or 60 times that value in minutes. This quotient assumes the gas can be delivered as required and ignores leakage and other losses not represented by the chosen conversion factor.
Water availability, cooling, feed capacity and pressure control are not inputs. The calculated total volume cannot establish a continuous delivery rate or safe charge capacity.
Worked example: a charge-yield estimate
Assume m = 1.0 kg, P = 0.82 and η = 0.95. The reacting mass is 1.0×0.82×0.95 = 0.779 kg = 779 g. This is 779/64.1 ≈ 12.153 mol, giving approximately 272.225 L or 0.272225 m³ at 0°C and 1 atmosphere.
At a hypothetical consumption of 0.4 m³/h at the same conditions, the equivalent time is 0.272225/0.4 ≈ 0.68056 h, or 40.83 minutes. This is a quantity calculation, not a named torch’s flow rating or a prediction of how many welds can be completed.
Keeping purity and conversion unchanged, 0.5 kg gives half the volume and 20.42 minutes, while 2 kg gives twice the volume and 81.67 minutes. The model does not automatically lower conversion when charge mass increases; such a change requires process data and a new η assumption.
As an upper stoichiometric reference using the model’s rounded constants, 1 kg of pure fully reacting CaC₂ gives about 349.45 L. Actual yield and usable delivery must be established for the material and equipment.
Comparing gas-supply arrangements
| Supply | What must be established |
|---|---|
| Carbide generator | Feed capacity, water and heat management, gas treatment, controls and residue handling. |
| Dissolved-acetylene cylinder supply | Compatible regulator and equipment, supplier withdrawal limits, storage and handling requirements. |
| Another fuel-gas system | Process suitability and compatible burner, supply equipment and instructions. |
Compare actual systems for capacity, logistics and cost. Gas identity alone does not establish an installation’s delivery pressure, maintenance interval or safety.
Generator questions
No. Total quantity differs from production and delivery capacity. Heat removal, feed controls, treatment and protective systems must support the required demand within the manufacturer’s ratings.
No. The drawing is a process illustration. It supplies no vessel dimensions, pressure rating, relief capacity or validated scale-up method.
Treat abnormal pressure as an equipment fault and follow the manufacturer’s shutdown and response instructions. Do not change a relief setting, add water or modify a feed system based on the calculator.
Purity, incomplete reaction, moisture history, leakage, gas reference conditions and measurement method can affect the comparison. The model does not identify a specific fault from the difference alone.
Not necessarily: material already in contact with water can continue reacting. Rated generators address this through their particular control and protective arrangements. Use their operating and shutdown procedures rather than assuming the animation represents those controls.
No such conclusion follows from color or appearance. Calcium hydroxide is alkaline, and residue may contain impurities or unreacted carbide. Follow the applicable material and equipment handling instructions; the calculator is not a disposal assessment.
No. Acetylene storage and filling require purpose-designed equipment and qualified procedures. A calculated volume does not authorize compression or filling of an improvised container.
References and further reading
- Science Museum Group: acetylene-generating plant, historical context.
- Rexarc: ATX acetylene generator, an example of dedicated industrial generation equipment.
- NIOSH: acetylene and calcium hydroxide, chemical-hazard information.
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