【Q&A Question 153】2016.09.20
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【Q&A Question 153】September 20, 2016: What should be noted during the normal operation as well as the start-up and shutdown of a reactor? The answer key will be available after responding; scoring is based on answering the key points. (1) During normal operation, it is necessary to monitor the pressure drop and temperature of the reactor bed in order to assess the equipment’s performance. Exceeding the specified temperature and pressure limits is strictly prohibited to protect the equipment and the catalyst. (2) During startup and shutdown, the rate of temperature and pressure changes must be strictly controlled to avoid uneven temperature distribution within the vessel and its components, which could lead to significant thermal stresses. (3) To prevent sulfide stress corrosion cracking in austenitic stainless steel components, the formation of polysulfates should be suppressed during shutdown, or alkaline solutions should be used to neutralize such corrosion products when they form. (4) When shutting down, measures should be taken to fully release the hydrogen energy stored in the operating state. For example, lower the pressure first, then reduce the temperature. (5) During startup and shutdown, efforts should be made to avoid the presence of liquid water and oxygen in the reactor.
Note: 1) During normal operation, it is necessary to monitor the pressure drop and temperature of the reactor bed in order to assess the equipment’s performance. Exceeding the specified temperature and pressure limits is strictly prohibited to protect the equipment and catalysts. (2) During startup and shutdown, the rate of temperature and pressure changes must be strictly controlled to avoid uneven temperature distribution within the vessel and its components, which could lead to significant thermal stresses. (3) To prevent sulfide stress corrosion cracking in austenitic stainless steel components, the formation of polysulfates should be suppressed during shutdown, or alkaline solutions should be used to neutralize such corrosion products when they form. (4) When shutting down, measures should be taken to fully release the hydrogen energy stored in the operating state. For example, lower the pressure first, then reduce the temperature. (5) During startup and shutdown, efforts should be made to avoid the presence of liquid water and oxygen in the reactor.
When the reactor is in normal operation, it is necessary to check whether there are any leaks in the flanges； If a leak is detected, contact the relevant party promptly for handling. What to pay attention to during startup, shutdown, and operation: Check for leaks in the flanges ； Heat-seal at 250°C and 350°C.
Lower the temperature first before reducing the volume, and increase the volume first before raising the temperature. The changes in temperature should not be too rapid to prevent hydrogen embrittlement. The speed at which pressure is reduced or increased should also not be too fast; hydrogen should be circulated during shutdown to avoid hydrogen corrosion
Pay attention to temperature rise, voltage drop, the temperature of each bed layer, check the thermocouples on the plug flanges, as well as the rates of pressure and temperature change, pressure difference variations, and so on
(1) During normal operation, it is necessary to monitor the pressure drop and temperature of the reactor bed in order to assess the equipment’s performance. Exceeding the specified temperature and pressure limits is strictly prohibited to protect the equipment and the catalyst. (2) During startup and shutdown, the rate of temperature and pressure changes must be strictly controlled to avoid uneven temperature distribution within the equipment and its components, which could lead to significant thermal stresses. (3) To prevent sulfide stress corrosion cracking in austenitic stainless steel components, the formation of polythiosulfates should be suppressed during shutdown, or alkaline solutions should be used to neutralize such corrosion products when they form. (4) When shutting down, measures should be taken to fully release the hydrogen energy stored during operation. For example, lower the pressure first, then reduce the temperature. (5) During startup and shutdown, efforts should be made to avoid the presence of liquid water and oxygen in the reactor.
(1) During normal operation, it is necessary to monitor the pressure drop and temperature of the reactor bed in order to assess the equipment’s performance. Exceeding the specified temperature and pressure limits is strictly prohibited to protect the equipment and the catalyst. (2) During startup and shutdown, the rate of temperature and pressure changes must be strictly controlled to avoid uneven temperature distribution within the equipment and its components, which could lead to significant thermal stresses. (3) To prevent sulfide stress corrosion cracking in austenitic stainless steel components, the formation of polythiosulfates should be suppressed during shutdown, or alkaline solutions should be used to neutralize such corrosion products when they form. (4) When shutting down, measures should be taken to fully release the hydrogen energy stored during operation. For example, lower the pressure first, then reduce the temperature. (5) During startup and shutdown, efforts should be made to avoid the presence of liquid water and oxygen in the reactor.
1) During normal operation, it is necessary to pay attention to the pressure drop and temperature of the reactor bed in order to assess the operating condition of the equipment; exceeding the allowed temperature and pressure limits is strictly prohibited to protect the equipment and catalysts. (2) During startup and shutdown, the rate of temperature and pressure changes must be strictly controlled to avoid uneven temperature distribution within the vessel and its components, which could lead to significant thermal stresses. (3) To prevent sulfide stress corrosion cracking in austenitic stainless steel components, the formation of polythiosulfates should be suppressed during shutdowns, or alkaline solutions should be used to neutralize these corrosion products once they form. (4) When shutting down, measures should be taken to fully release the hydrogen energy stored during operation. For example, lower the pressure first, then reduce the temperature. (5) During startup and shutdown, efforts should be made to avoid the presence of liquid water and oxygen in the reactor.
(1) During normal operation, it is necessary to monitor the pressure drop and temperature of the reactor bed in order to assess the equipment’s performance. Exceeding the specified temperature and pressure limits is strictly prohibited to protect the equipment and the catalyst. (2) During startup and shutdown, the rate of temperature and pressure changes must be strictly controlled to avoid uneven temperature distribution within the vessel and its components, which could lead to significant thermal stresses. (3) To prevent sulfide stress corrosion cracking in austenitic stainless steel components, the formation of polysulfates should be suppressed during shutdown, or alkaline solutions should be used to neutralize such corrosion products when they form. (4) When shutting down, measures should be taken to fully release the hydrogen energy stored in the operating state. For example, lower the pressure first, then reduce the temperature. (5) During startup and shutdown, efforts should be made to avoid the presence of liquid water and oxygen in the reactor.
The rate of temperature increase/decrease, as well as the rate of pressure increase/decrease, must not exceed specified limits to avoid overheating or overpressure