Questions for November 16, 2017; replies can earn 0–6 points (no scoring for replies sent more than 1 day after posting. Thank you for your replies)

1. Feed interruption causes the heating furnace to shut down rapidly, with little steam supplied behind the feed control valve to protect the furnace tubes. Other heating furnaces cool down rapidly. 2. Quickly activate the backup pump and address the feed pump to restore its flow rate. 3. If the feed pump fails to deliver flow for a short period, the crude oil flow decreases, and the temperatures on the reflux sides of various columns drop; it is necessary to maintain the material balance and pressure ahead of the feed pump in order to prevent column flooding. 4. Reduce the flow rate behind the feed pump to maintain the liquid level at the bottom of the tower as well as in the various tanks and side lines, thereby preventing the pump from running dry. e. If the feed pump is unable to increase its flow rate for an extended period of time and the material balance cannot be maintained, treat it as an emergency shutdown. 5. If it is caused by a crude oil disruption, handle it according to the procedures for such disruptions.

The key to preventing interruptions in the feed to the heating furnace is to ensure that the furnace does not overheat and to maintain material balance in each tower. 1. Phenomena: (1) The temperatures at the outlet of the heater and at the branch points rise sharply, the fuel supply decreases, and the temperature of the exhaust gases at the outlet increases. (2) The liquid level in the front tower bottom rises rapidly, while the liquid level in the back tower bottom drops sharply. 2. Causes: (1) The feed pump of the heater is running dry. (2) The inlet of the feed pump is blocked. (3) The supply of crude oil is interrupted or the crude oil pump has stopped operating. 3. Remedial actions: (1) If the feed is interrupted, the heater should be shut down immediately, and less steam should be supplied behind the feed control valve to protect the furnace tubes. Other heating furnaces should be cooled down rapidly. (2) Activate the backup pump immediately and address the feeding pump so that it can resume operation. (3) If the feeding pump fails to deliver fluid for a short period, resulting in a decrease in crude oil flow, the reflux lines of each column should be cooled down; it is necessary to maintain the material balance and pressure ahead of the feeding pump, prevent a drop in pressure behind the pump, and keep the liquid levels in the bottom of the column as well as in various tanks and side lines, thereby avoiding pump cavitation. (4) If the feeding pump cannot operate for an extended period and the material balance cannot be maintained, emergency shutdown procedures should be followed. If the issue is caused by a disruption in crude oil supply, measures appropriate for such a disruption should be taken

The key to preventing interruptions in the feed to the heating furnace is to ensure that the furnace does not overheat and to maintain material balance in each tower. 1. Phenomena: (1) The temperature at the outlet of the heating furnace and at the branch points rises sharply, the fuel consumption decreases, and the temperature of the flue gas at the outlet increases. (2) The liquid level at the bottom of the front tower rises sharply, while the liquid level at the bottom of the rear tower drops sharply. 2. Reasons: (1) Vacuum formation in the feed pump of the heating furnace; (2) Blockage at the inlet of the feed pump; (3) Disruption in crude oil supply or shutdown of the crude oil pump. 3. Handling: (1) In the event of a feed interruption, the heating furnace shuts down immediately, and a small amount of steam is supplied behind the feed control valve to protect the furnace tubes. Other heating furnaces should be cooled down rapidly. (2) Activate the backup pump immediately and address the feed pump so that it can resume operating at normal capacity. (3) If the feed pump fails to operate at normal capacity for a short period, resulting in a decrease in crude oil flow, the reflux lines of each tank should be cooled down; it is important to maintain the material balance and pressure before the feed pump in order to prevent overpressure in the tower. The flow rate behind the feed pump should also be controlled to maintain the liquid level at the bottom of the tower as well as in all tanks and side lines, thereby preventing the pump from running dry. (4) If the feed pump cannot operate at normal capacity for an extended period and the material balance cannot be maintained, emergency shutdown procedures should be followed. If the issue is caused by a disruption in crude oil supply, measures appropriate for such a disruption should be taken.

It falls under emergency incident handling. If the feed is interrupted, immediately shut off the main burner of the heating furnace.

The key to preventing interruptions in the feed to the heating furnace is to ensure that the furnace does not overheat and to maintain material balance in each tower. 1. Phenomena: (1) The temperatures at the outlet of the heater and at the branch points rise sharply, the fuel supply decreases, and the temperature of the exhaust gases at the outlet increases. (2) The liquid level in the front tower bottom rises rapidly, while the liquid level in the back tower bottom drops sharply. 2. Causes: (1) The feed pump of the heater is running dry. (2) The inlet of the feed pump is blocked. (3) The supply of crude oil is interrupted or the crude oil pump has stopped operating. 3. Remedial actions: (1) If the feed is interrupted, the heater should be shut down immediately, and less steam should be supplied behind the feed control valve to protect the furnace tubes. Other heating furnaces should be cooled down rapidly. (2) Activate the backup pump immediately and address the feeding pump so that it can resume operation. (3) If the feeding pump fails to produce flow for a short period, resulting in a decrease in crude oil flow, the reflux lines of each tank should be cooled down; it is important to maintain the material balance and pressure ahead of the feeding pump in order to prevent flooding of the tower. The flow rate behind the feeding pump should also be controlled to maintain the liquid level at the bottom of the tower as well as in each tank and side line, thereby preventing the pump from running dry. (4) If the feeding pump cannot operate for an extended period and the material balance cannot be maintained, emergency shutdown procedures should be followed. If the issue is caused by a disruption in crude oil supply, actions appropriate to such a disruption should be taken

1. Feed interruption causes the heating furnace to shut down rapidly, with little steam supplied behind the feed control valve to protect the furnace tubes. Other heating furnaces cool down rapidly. ? 2. Quickly activate the backup pump and address the feed pump to restore its flow rate. ? 3. If the feed pump fails to deliver flow for a short period, the crude oil flow decreases, and the temperatures on the reflux sides of various columns drop; it is necessary to maintain the material balance and pressure ahead of the feed pump in order to prevent column flooding. ? 4. Reduce the flow rate behind the feed pump to maintain the liquid level at the bottom of the tower as well as in the various tanks and side lines, thereby preventing the pump from running dry. e. If the feed pump is unable to increase its flow rate for an extended period of time and the material balance cannot be maintained, treat it as an emergency shutdown. ? 5. If it is caused by a crude oil disruption, handle it according to the procedures for such disruptions.

The key to preventing interruptions in the feed to the heating furnace is to ensure that the furnace does not overheat and to maintain material balance in each tower. 1. Phenomena: (1) The temperatures at the outlet of the heater and at the branch points rise sharply, the fuel supply decreases, and the temperature of the exhaust gases at the outlet increases. (2) The liquid level in the front tower bottom rises rapidly, while the liquid level in the back tower bottom drops sharply. 2. Causes: (1) The feed pump of the heater is running dry. (2) The inlet of the feed pump is blocked. (3) The supply of crude oil is interrupted or the crude oil pump has stopped operating. 3. Remedial actions: (1) If the feed is interrupted, the heater should be shut down immediately, and less steam should be supplied behind the feed control valve to protect the furnace tubes. Other heating furnaces should be cooled down rapidly. (2) Activate the backup pump immediately and address the feeding pump so that it can resume operation. (3) If the feeding pump fails to produce flow for a short period, resulting in a decrease in crude oil flow, the reflux lines of each tank should be cooled down; it is important to maintain the material balance and pressure ahead of the feeding pump in order to prevent flooding of the tower. The flow rate behind the feeding pump should also be controlled to maintain the liquid level at the bottom of the tower as well as in each tank and side line, thereby preventing the pump from running dry. (4) If the feeding pump cannot operate for an extended period and the material balance cannot be maintained, emergency shutdown procedures should be followed. If the issue is caused by a disruption in crude oil supply, actions appropriate to such a disruption should be taken

The key to preventing interruptions in the feed to the heating furnace is to ensure that the furnace does not overheat and to maintain material balance in each tower. 1. Phenomena: (1) The temperatures at the outlet of the heating furnace and at the branch points rise sharply, the fuel supply decreases, and the temperature of the exhaust gas at the outlet increases. (2) The liquid level in the front tower bottom rises sharply, while the liquid level in the back tower bottom drops sharply. 2. Causes: (1) The feed pump of the heating furnace loses suction. (2) The inlet of the feed pump is blocked. (3) The supply of crude oil is interrupted or the crude oil pump stops operating. 3. Remedial actions: (1) If the feed is interrupted, the heating furnace should be shut down immediately, and less steam should be supplied behind the feed control valve to protect the furnace tubes. Other heating furnaces should be cooled down rapidly. (2) Activate the backup pump immediately and address the feeding pump so that it can resume operation. (3) If the feeding pump fails to deliver flow for a short period of time, causing a reduction in crude oil flow, the reflux lines of various tanks should be cooled down; it is necessary to maintain the material balance and pressure before the feeding pump in order to prevent flooding of the tower. The flow rate behind the feeding pump should also be controlled to maintain the liquid level at the bottom of the tower as well as in all tanks and side lines, thereby preventing the pump from running dry. (4) If the feeding pump cannot resume operation for an extended period of time and the material balance cannot be maintained, emergency shutdown procedures should be followed ； If it is caused by a crude oil disruption, it shall be handled as per the procedures for such disruptions.

Accident symptoms: 1. The total feed flow rate of crude oil dropped sharply, with both feed streams being interrupted; 2. The pressure in the electrodialysis tank decreased; 3. The heat exchange temperatures for both streams increased; 4. The liquid level in the primary distillation tower dropped rapidly. Shift leader: 1. Report to the dispatch team immediately and inform the on-duty personnel in the workshop. 2. Direct, coordinate, and assist in the work of various positions. Internal operations: 1. Order external operations to start the crude oil standby pump immediately. 2. If the standby pump still does not deliver sufficient flow, reduce the outlet temperatures of the atmospheric furnace and the vacuum furnace, as well as the feed rates to these furnaces, in order to prevent overheating. External operations: 1. Start the standby pump right away. 2. If the standby pump still does not deliver sufficient flow, shut off the fuel, gas, and flame supplies to the atmospheric furnace and the vacuum furnace. 3. Close the main vacuum valve to restore normal pressure, and also close the E–125 vent valve. 4. Stop the blower and the exhaust fan

The key to preventing interruptions in the feed to the heating furnace is to ensure that the furnace does not overheat and to maintain material balance in each tower. 1. Phenomena: (1) The temperatures at the outlet of the heater and at the branch points rise sharply, the fuel supply decreases, and the temperature of the exhaust gases at the outlet increases. (2) The liquid level in the front tower bottom rises rapidly, while the liquid level in the back tower bottom drops sharply. 2. Causes: (1) The feed pump of the heater is running dry. (2) The inlet of the feed pump is blocked. (3) The supply of crude oil is interrupted or the crude oil pump has stopped operating. 3. Remedial actions: (1) If the feed is interrupted, the heater should be shut down immediately, and less steam should be supplied behind the feed control valve to protect the furnace tubes. Other heating furnaces should be cooled down rapidly. (2) Activate the backup pump immediately and address the feeding pump so that it can resume operation. (3) If the feeding pump fails to produce flow for a short period, resulting in a decrease in crude oil flow, the reflux lines of each tank should be cooled down; it is important to maintain the material balance and pressure ahead of the feeding pump in order to prevent flooding of the tower. The flow rate behind the feeding pump should also be controlled to maintain the liquid level at the bottom of the tower as well as in each tank and side line, thereby preventing the pump from running dry. (4) If the feeding pump cannot operate for an extended period and the material balance cannot be maintained, emergency shutdown procedures should be followed. If the issue is caused by a disruption in crude oil supply, actions appropriate to such a disruption should be taken