Sufficient attention should be paid to the problems in the application of catalytic combustion devices

A large amount of organic waste gas containing benzene, alcohol, ketone and other volatile substances is discharged during industrial production, which endangers workers’ health and causes environmental pollution. Since the 1980s, catalytic combustion devices have been widely applied for waste gas treatment and have achieved remarkable treatment effects in China. However, potential safety risks still exist in the design, manufacturing and application processes. Fires and explosion accidents have occurred in Beijing, Shanghai, Shenyang and other regions due to inadequate safety measures. Therefore, sufficient attention must be paid to the safe application of catalytic combustion equipment.

Improper operation may lead to severe accidents such as fire and explosion. Unified concentration control standards and design specifications for catalytic combustion waste gas treatment shall be formulated. In addition, other technical safety risk factors are analyzed as follows:

1. Relationship Between Explosion Lower Limit and Temperature

Generally, higher temperature accelerates chemical reaction rate and expands the explosion concentration range. Excessively high waste gas concentration will cause temperature rise inside the catalytic combustion device. Most domestic equipment lacks automatic gas concentration detection and control systems. The actual lower explosion limit at high temperature is lower than the standard data provided in equipment manuals. In addition, uneven gas mixing may cause local concentration to exceed the real high-temperature explosion limit, resulting in explosion hazards.

2. Combustion Calorific Value of Organic Waste Gas

Under the same lower explosion limit, most organic waste gas components have approximately equal combustion calorific value. Every 1% lower explosion limit contains a calorific value of 18.68 kJ/Nm³. If all heat is used for gas self-heating, every 1% explosion limit concentration can raise the gas temperature by 15.3°C. When the waste gas concentration reaches 25% of the lower explosion limit, significant temperature rise will occur inside the equipment.