【Q&A Question 125】2016.08.23
Thread Content
This post was last edited by liuquan1100 on 2016-8-24 at 16:56. [Q&A Question 125] 2016.08.23: Under what circumstances is it necessary to shut down the furnace urgently during production? The answer key will be available after responding; scoring is based on addressing the key points. 1. Feed interruption 2. Emergency pressure relief 3. Circulator shutdown 4. Burnthrough of furnace tubes, furnace tube leakage 5. Built-in interlocks of the furnace, such as low fuel gas pressure, excessive temperature in the outlet branch, or feed flow below the interlock value.
Circulating hydrogen supply was interrupted, the reaction feed was halted, gas pressure was too low, furnace temperature was too high, outlet temperature of the furnace was too high; a fire and explosion occurred, and the furnace tubes were burned through
First, the outlet temperature of the furnace is severely elevated, and it continues to rise. Second, the furnace tubes inside the furnace are leaking, and the leakage is showing a tendency to increase. Third, fires or other accidents occurring near the furnace pose a direct threat to its safe operation. Fourth, the furnace wall collapsed. Fifth, during normal operation, if the feed to the unit is suddenly interrupted and cannot be restored, a chain emergency shutdown must be initiated. Sixth, in the event of an accident within the installation – such as high pressure connecting to low pressure, a leak in the pressure vessel, problems with the fan of the furnace that lead to its shutdown, or power or air supply interruptions – it is necessary to shut down the furnace immediately.
There are many reasons for stopped instrument air, power outages, leaks, and fires
1. Stop the circulation machine； 2. Breakage of the heating furnace tubes 3. Plant shutdown due to interlock protection
Fuel gas supply interrupted, feed oil supply interrupted
1). The boiler water level is below the limit value. 2). The boiler water level is above the limit value. 3). When all the water level gauges of the boiler are damaged. 4) When tube explosion prevents the maintenance of a normal water level in the drum. 5) When reignition occurs in the tail flue, causing the exhaust gas temperature to rise abnormally. 6) When the main feedwater and steam pipes burst, posing a threat to the safety of equipment or personnel. 7) When the main steam pressure exceeds the operating pressure of the safety valves yet these do not operate, and the exhaust valve to the atmosphere cannot be opened. 8) When the reheat steam is interrupted. 9) All high-pressure fluidization fans (or exhaust fans, secondary fans, primary fans) stop operating due to failures. 10) A fire breaks out in the boiler room, causing severe damage to the equipment; or a fire in the boiler room directly affects the safe operation of the boiler ； 11) When the boiler shuts down due to a fire. 12) When an explosion occurs in the furnace or flue, causing severe damage to the equipment. 13) When the conditions for MFT operation are met but the protection fails to activate. 14) When all thermal control power supplies are interrupted, making it impossible to monitor or control the boiler’s operation. 15) In the event of an emergency shutdown of the turbine or electrical systems.
The water level is extremely low, the water level is extremely high, and the safety valve is not functioning
1. When the boiler pressure rises above the rated value, the safety valve does not activate； 2. Uncontrolled rise or fall in water level ； 3. Severe damage to water supply facilities or safety accessories ； 4. Collapse of the furnace wall or damage to boiler components poses a safety risk.
Overheating, air supply failure, power outages, pipe bursts, leaks, and many other factors