Cause analysis and treatment methods for flashback in gasifiers?
Thread Content
Reasons for flashback in the gasification furnace: 1. High liquid level in the quench chamber of the gasification furnace, with water blocking the downcomer of the furnace, resulting in negative pressure turning into positive pressure. 2. Large fluctuations in the steam extraction pressure and unstable negative pressure cause the furnace to go into flashback. 3. Fluctuations in fuel gas flow rate. 4. The system has leaks, or the manway valve has been manually removed, resulting in unstable flames. 5. Blockage at the bottom of the extraction and separation tank, resulting in poor steam drainage and backflow. Handling method: Immediately shut off the fuel gas and stop drying the furnace. After ruling out the above issues, increase the load and draw for 30 minutes; once the combustible gas meets the requirements, proceed with igniting the furnace for heating.
The silencer is clogged, the pipes are blocked, which affects negative pressure and causes backfire.
A clogged silencer and blocked pipes do make some sense. However, steam or fuel gas flows through it, so the possibility of blockage should be quite low, right? Has your plant encountered similar situations before? Thank you for participating/
Reply to 2# fangyifang: The silencer is clogged and the pipes are not flowing properly; what he said makes some sense. However, steam or fuel gas flows through it, so the possibility of blockage should be quite low, right? Has your plant encountered similar situations before? Thank you for participating/
The cause of tempering is insufficient fuel gas and an adequate amount of combustion-supporting gas. From the perspective of pipe combustion, the amount of gas decreases as the valve is closed; the flame shifts from pilot combustion to natural combustion, and then the flame shape becomes smaller until it eventually goes out. If the gas is cut off too quickly, this causes the flame to go out too rapidly, resulting in excessive negative pressure around the nozzle. This leads to the accumulation of combustion gas at the nozzle, which can easily cause backflow. To prevent tempering, the assist gas can be cut off first, followed by the fuel gas, or the fuel gas can be cut off slowly
When the extractor is blocked, the temperature cannot rise, and increasing the fuel gas can easily cause backflow.
During preheating, the slag adhering to the furnace wall melts and blocks the slag outlet, making it difficult to create a negative pressure and resulting in tempering.