Inside an RX Generator: Retorts, Catalyst, Mixing, and Cooling

• Mixing system: precise control of the ratio of air and gas is the source of gas quality
• Reaction tank + nickel catalyst: complete cracking at high temperature
• Heating system: maintains the temperature required for endothermic reactions
• Cooler: Rapid cooling to prevent carbon black
• Controls and interlocks: dew point/carbon potential control, temperature control, flame and pressure protection

Overall process

Air + gas → Proportional mixing → Mixed gas pump pressurization → Reaction tank (high temperature catalytic cracking) → Cooler → Filtration/pressure stabilization → Send to heat treatment furnace

1. Air-fuel ratio mixing system

This is a key link in determining gas quality. Air and gas are mixed according to the set ratio through the flow meter and regulating valve (or proportional valve), and the proportion is fine-tuned to control the outlet dew point or carbon potential.

• Traditional method: mechanical proportional valve + manual fine adjustment;
• Modern way: electronic proportional control, automatically adjusts the air or gas branch according to the dew point/oxygen probe signal.

The Gosi Control ENDOMATE™ series adopts an electronically controlled proportional control system. According to the official website, one of its functions is to reduce the risk of shutdown and support multiple gas production modes to reduce emissions and energy waste.

2. Mixing air pump

Pressurize the mixed gas into the reaction tank to ensure sufficient outlet pressure within the entire adjustment range (gas production from low to high). Some designs use positive displacement pumps to achieve stable flow.

3. Reaction tank and catalyst

• reaction tank: Heat-resistant alloy centrifugal cast pipe or welded pipe, which works under high temperature for a long time, is one of the most critical components for the generator life;
• catalyst: Usually nickel-loaded refractory particles, filled in the reaction tank. The decrease in catalyst activity will lead to an increase in residual methane and carbon black.

The number of reaction tanks determines the gas production capacity. Common designs range from single tube to multiple tubes, and a single large generator can reach hundreds of cubic meters per hour.

4. Heating system

Since pyrolysis is endothermic, external heating is required to maintain the reaction temperature:

• Electric heating: Accurate temperature control, no combustion exhaust gas, suitable for workshops with high environmental requirements;
• gas heating: Operating costs may be lower, burner and flue gas emissions management required.

5. Cooler

The outlet gas needs to be cooled down quickly to avoid the carbon precipitation range of about 450–700 °C. Common methods include water-cooled heat exchangers and air-cooled heat exchangers. Carbon deposits or insufficient cooling in the cooler can cause carbon black and composition changes.

6. Control and Security

• Reaction tank temperature control and over-temperature protection;
• Dew point or carbon potential closed loop control (oxygen probe or dew point sensor);
• Gas low pressure/high pressure, air pressure, mixed gas pressure interlock;
• Flame detection (gas heating type);
• Start and stop procedures: nitrogen purging, heating, ignition, gas production, and charcoal burning;
• Data recording and alarming meet CQI-9 requirements for generator atmosphere monitoring.