The world's leading calcium carbide supplier.
Acetylene Production Process Optimization: Precisely Matching Calcium Carbide Purity with Hydrolysis Temperature
2026-01-12
Matching the calcium carbide with the right hydrolysis temperature is key for safety and maximizing the acetylene production rate. The hydrolysis process is highly exothermic. 1 kg of calcium carbide can release 1985.6 kJ of heat when reacting with water. If not controlled, the temperature can rise and cause acetylene to decompose explosively.
Acetylene (C2H2) is a critical raw material for many chemical manufacturing processes, such as PVC, vinyl acetate, and welding. It is the only commercially available gas that can reliably weld steel. Other high-heat processes need electricity and specialized gas, as in TIG/MIG. The oxy-acetylene gas mixture can reach temperatures of up to 3150 °C. It's a valuable gas, and improving its yield can help industrialists maximize profits and lower losses.
This article will elaborate on the hydrolysis process and its key parameters that the user needs to control. Then it will explain how we can use commercially available calcium carbide and optimize acetylene production. Mention the advanced strategies to optimize the process further. Lastly, mention the future direction.
Calcium Carbide Hydrolysis in Acetylene Production
Reaction Mechanism and Thermodynamics
The core reaction that leads to the production of acetylene is calcium carbide in water.
CaC₂ + 2H₂O → C₂H₂ + Ca(OH)₂ + Heat
The heat that is produced from the reaction needs to be controlled as it can rapidly raise the temperature. Increasing the temperature of the reaction is good for acetylene production, but if it reaches >350 °C, the acetylene will start to polymerize, which is undesirable and leads to a lower yield of acetylene. However, if the temperature keeps rising (400–600 °C), it can lead to explosive decomposition, which is a critical safety concern. Here are two key aspects to consider:
Pressure and Heat Control
Controlling the temperature and pressure of an enclosed generator within which the highly exothermic reaction is taking place is vital. Reactor generators are industrially classified into Low-Pressure and Medium-Pressure types. Controlling the pressure of the enclosed generator to ensure it never exceeds the critical safety limit of 15 psig (approximately 2 atm absolute) is key to preventing the explosive decomposition of acetylene. The typical heat capacity of slurry is approximately Cp=4.2 J/g°C. It requires approximately 500kJ/kg of cooling for a 50°C rise (Wang et al., 2024)
Calcium Carbide Particle Size
The surface area of the particle that interacts with water is also a key parameter in the reaction. Granules with a high surface area, typically 15-25mm, can reach equilibrium state within 5 minutes at 50 °C for a 310-320 L/kg yield. In comparison, a granule size of 80-120mm will take 10-15 minutes. Finer particles accelerate the rate by as much as 2x.
Analyzing Purity and Temperature
The two parameters play a critical role in ensuring that the acetylene production is optimized.
Temperature Kinetic Boost
Analyzing the thermodynamic response of a reaction can be theoretically optimized using Aspen Plus simulations. One such study done by Wang et al. (2024 suggests that operating at a temperature between 70-80 °C significantly accelerates the reaction. The energy required to create the reaction of calcium carbide and water is reduced by 10-15 kJ/mol.
Ideal High Purity (>90%) and Temperature Control Window
While high purity >90% is the target, it is not commercially achievable. Ideally,>92% allows a wider temperature range for operation. There is a 45-70 °C window that allows more flexibility for the operators. Alongside the flexibility in temperature operation, the reaction is also very predictable with <3% change. The gas is much cleaner, and the chances of corrosion are very low. The output of the process is also high, with 300-320 L/kg.
Standard Purity (75-85%) and Temperature Control Window
The standard purity range is commercially viable. It comes with a tighter window for controlling temperature, typically a 70-80 °C window. There are side reactions that result in toxic gas production, but they are controllable. The whole reaction still provides significant gas yields of 300L/kg with 80.6% purity. It is not far away from the ideal acetylene production per kilogram of calcium carbide used. The temperature range is selected to avoid the risk of runaway if the heat leads to a temperature of 100°C. The corrosion causes vessel pitting up to 0.6mm/year, making the final acetylene 0.15-0.25kg more expensive to produce, but it's commercially viable.
Cooling Optimization
The water is the source of cooling in the reaction and also the critical part of the reaction. Selecting the right quantity is key. If we use the chemical reaction alone, we only need 0.56 L of water per kilogram of calcium carbide. However, it does not impart the cooling effect. For industrial applications, we need 5-20 L/kg, which allows the reaction to stay between the safe 70-80 °C, which is significantly below the runaway risk of 100 °C for safe operation. Optimizing the ratio of water can lead to optimization.
One study done by Rodygin et al. (2022) indicates that a ratio of 2:1 or 3:1 can save 15-20% energy and reduce slurry Ca(OH)2 volume by 20%. However, practically, it can become challenging to control and find good yields. Therefore, the 5-20 /kg is more practical.
Commercial Calcium Carbide Products and Their Optimization Potential
We have now established that the calcium carbide purity and hydrolysis temperature play a key role in the production of acetylene. Let's analyze what the particle size, when matched with the right temperature, can provide.
Let's consider TYWH (Tianjin TYWH Chemical Co., Ltd.), a major producer of calcium carbide from China. Their production rate is stunning, 120,000 tons/year. Their products are oriented for industrial consumers and widely used for acetylene production.
TYWH Product Portfolio Overview
TYWH uses airtight drums that can handle 50kg or 100 kg of calcium carbide. These drums are ready for shipment and comply with the ISO 9001/14001 standard. Their shelf life is around 12-18 months, and they typically keep the moisture in the air-tight drums under 1%.
The produce is in line with the international standards, which necessitate that the ash is <1%. All the products from TYWH contain toxic impurities, PH3＜0.04% and H2S＜0.06%. The product is ideal for hydrolysis, with minimal toxins produced that are in line with industry standards.
Matching TYWH Grades to Hydrolysis Conditions
For the best acetylene gas yields, the key is optimization of temperature and matching with the right purity. The result is a higher efficiency of the production process. Here is a table representing the TYWH product grades and their relevant parameters when going through the production process of acetylene production:
|
CaC2 (%) |
63.14 |
68.52 |
72.54 |
73.89 |
75.2 |
76.57 |
77.91 |
80.6 |
81.95 |
83.29 |
|
Gas yield(L/KG) |
235 |
255 |
270 |
275 |
280 |
285 |
290 |
300 |
305 |
310 |
Key Benefits of Optimizing Acetylene Production
Energy and Yield
Optimizing this match can reduce heat waste by 20–25%, raise exergy efficiency to about 73.2% in integrated biomass systems, and save about $0.20 per kilogram in energy costs.
Scale-Up
Smaller 15–25 mm grades are used in pilot systems producing less than 10 kilograms per hour. Larger 80–120 mm grades are used in plants producing more than 1 ton per hour, where they deliver a 5–10% yield advantage when operated at the correct temperature.
Impurity-Control Savings
Using high-purity grades at their matched temperatures also reduces the amount of scrubber media needed after hydrolysis by 15–20%, effectively doubling the media’s service life.
Advanced Optimization Strategies: Integrating Heat Management and Sustainability
The modern approach to manufacturing ensures a cleaner environment and incorporates technology to enhance monitoring and control. The result is cleaner, efficient, and lower corrective maintenance jobs. Here are the three areas where modern acetylene production is headed:
● Heat Recovery: Using advanced heat exchangers that utilize the waste heat to pre-heat water or make steam can lead to an increase in efficiency. The energy required to produce acetylene will reduce drastically. Some heat exchangers can recover 45% of waste heat.
● Green Technologies: Integrating biomass (BCCA) and recycling waste using calcium looping can reduce the carbon footprint of the whole process by 65%.
● Smart Controls: Incorporating the latest technologies like AI (Artificial Intelligence) and IoT (Internet of Things) devices can lead to real-time monitoring and analysis of the process. The result is a quick adjustment of parameters and better control, leading to an increase of 25% in yields. Moreover, it drastically reduces the need for maintenance through equipment healthiness checks.
Conclusion
Acetylene is a valuable gas that is used in welding and the formation of plastics or polymers. The most widely used production process is the use of calcium carbide with water. It is the most commercially viable process that has a high yield, and the process is less complicated. In this article, we explored how the temperature of the reaction affects the acetylene production. The effect of calcium carbide particle size and purity on the yield of acetylene. Moreover, we combined their effects to find the perfect match for calcium carbide purity, particle size, and hydrolysis temperature. The best case scenario came out to be using high purity >80% calcium carbide and controlling the temperature 70-80 °C. Ensuring safety requires that the temperature remain below 100 °C. Therefore, operating with a safety margin is key.
However, every industry may find different temperatures and purity ideal for acetylene production; the key study remains the same.
recommended for you
no data
Get in touch with us
Head Office: Room 438, No. 58 Wanxiang Road, Gulin Street, Binhai New Area, Tianjin,China
Factory: Laoshidan Project Area of Hainan Industrial Park, Hainan District, Wuhai City, Inner Mongolia, China