[Request for Upload Summary] Operating Procedures for Ammonia Storage Position (Production Plan)

This is our company’s: Operating Procedures for the Ammonia Storage Unit. 1. Responsibilities This unit is responsible for the centralized storage and transfer sales of liquid ammonia at ×× Company. Its task is to store most of the liquid ammonia produced by the XX and XX systems ； Provide liquid ammonia for use in urea production in the urea plant ； Sales of liquid ammonia and filling for external use ； The liquid ammonia delivered by the Yongnitrogen branch is unloaded into the liquid ammonia storage tank in this section. The equipment in this section consists of three liquid ammonia storage tanks with dimensions of Φ2800×24×16920 and a volume of V=100 m3 each. II. Process Parameters <1> Pressure in the liquid ammonia tank: 2.0–2.1 MPa <2> Liquid level in the liquid ammonia tank (per tank): 10–80 m3 <3> Temperature of the liquid ammonia in the tank: ≤40°C III. Operating Procedures <1> Adjust the pressure in the liquid ammonia tank using the vent valve; it is not allowed to exceed 2.2 MPa. (II) The switching of the main valve for liquid ammonia supplying urea is controlled by the chief dispatcher; under normal circumstances, it is not allowed to be closed. Once the use of ammonia for urea production stops, close attention must be paid to the pressure in the main urea liquid ammonia pipeline. When the pressure becomes excessively high, it is necessary to immediately relieve the pressure by using the vent valve on the ammonia tank. (III) The ×× system produces ammonia, and the ×× system also produces ammonia, which is sent to the urea system; the use of ammonia should be carried out in separate tanks. In special cases, the matter shall be handled only after approval by the chief dispatcher, and proper recording and measurement must be carried out. (IV) For the tank switching operation, under normal circumstances, it should be carried out in the following order: open the ammonia inlet valve of the tank to be used → close the ammonia inlet valve of the original tank → open the ammonia outlet valve of the tank to be used → close the ammonia outlet valve of the original tank. The reversing action must be quick, the valve must be opened and closed properly, and the readings must be accurate. IV. Safety Precautions 〈1〉Except in special cases where the liquid level in the ammonia inlet tank is ≥80 m3 or the liquid level in the ammonia delivery tank is ≤10 m3, the tank can only be emptied once per shift, after taking over the shift. (II) Maintain regular contact with the synthesis team to keep track of the ammonia supply for synthesis, and prevent leaks in this ammonia supply from causing overpressure in the liquid ammonia tank. (III) It is strictly prohibited for personnel from other positions to manipulate the valves arbitrarily. (IV) Open flames and smoking are strictly prohibited within the ammonia storage area. (5) Ensure that gas masks, water supply and drainage facilities, and protective equipment are in proper working condition. 〈6〉The personnel taking over and handing over duties should verify the condition of all control valves as well as the liquid levels in the three tanks. 〈7〉They should be aware of the operational status of the station. (8) The liquid ammonia storage area should be equipped with shading structures and water supply and drainage facilities as preventive measures against liquid ammonia leaks. 9. The filling level of the liquid ammonia tank shall not exceed 85% of the total volume of the tank. When it is below 10%, the groove must be reversed to prevent air leakage. 〈10〉 The pressure in the liquid ammonia storage tank shall not exceed 2.25 Mpa, and the amount of liquid ammonia stored shall not exceed 85% of the total volume. 〈11〉All electrical installations (including lighting fixtures, etc.) shall be explosion-proof. 〈12〉 Liquid ammonia storage tanks must be equipped with safety valves, which should be inspected and adjusted in a timely manner as required. The safety valves shall have pipes, and these pipes must be at a height of more than 2 meters above the factory building.

Tasks of the position under the responsibility system: Store and transport liquid ammonia. When the urea production plant is operating at reduced capacity or is shut down, any excess liquid ammonia is sent to the ammonia storage tank for storage. When the urea production increases and there is a shortage of synthetic liquid ammonia, the ammonia storage tank can be used to supply the missing amount. When there is an excess of liquid ammonia in the refrigeration system or when it is not needed, that liquid ammonia can be sent to the storage tank again. Key points for normal operation: 1. Once liquid ammonia is introduced into the storage tank, normal operation resumes. Even when the external systems are shut down, liquid ammonia still remains in the tank, and it must be controlled under normal operating conditions. 2. During normal operation, the liquid level LIAS-1501-1/2 in the ammonia tank must be maintained between 20% and 85%. When it approaches the alarm threshold, it is necessary to contact external parties to stop the supply of ammonia or cease the output of liquid ammonia in order to keep the liquid level in the tank within the normal range. 3. The pressure inside the ammonia tank should be maintained between 0.35–0.4 MPa under normal operation; if it reaches 0.4 MPa, the small refrigeration unit system should be activated. When the pressure in the ammonia tank drops to 0.35 MPa, it is necessary to reduce the load on the small chiller in order to keep the pressure in the tank above 0.35 MPa; if the pressure in the tank exceeds 0.4 MPa, PIC-1503 automatically opens to allow venting. 4. During operation, the pressure in the ammonia tank of the synthetic ice machine is controlled by the inlet pressure of the ice machine, while the small ice machine system is in a stopped state. 5. During normal operation, one of the liquid ammonia pumps (J011502a, b) should be in cold standby, while the heaters (C011502a, b) should be in hot standby. 6. The liquid ammonia pump should not be stopped under normal circumstances; when ammonia is not required in the external process units, open the reflux valve fully and close the outlet valve, allowing the ammonia pump to continue circulating. Emergency shutdown: 1. Press the emergency shutdown button to stop the compressor from operating. 2﹑Close the suction and exhaust stop valves. 3. Cut off the power supply; proceed with the rest of the procedures as usual. 4. The liquid ammonia pump shall, in accordance with the dispatch instructions, fully open the reflux valve, close the pump outlet valve, and stop the ammonia supply. Normal startup and shutdown: For screw chillers, during startup and shutdown: 1. Starting a screw chiller: 1) Rotate the shaft to check for any blockages, and set the “manual/auto” switch to the “manual” position. 2) Turn on the power control switch, check the voltage, and verify whether the lamp is functioning properly. 3) Start the oil pump and check whether the oil pressure is normal. (It should be 0.3 Mpa higher than the exhaust pressure.) 4) Check whether the energy indicator is at zero; turn the four-way valve handle to the unloaded position. 5) Start the compressor and open the suction valve; gradually increase the load on the small chiller in several steps, keeping the outlet pressure at ≤1.5 Mpa. If the pressure is too high, open the valve on the air separator and activate it. 6) Check the inlet and outlet pressures, oil temperature, oil pressure, oil level of the small chiller, as well as for any abnormal noises; verify that the oil pressure is 0.15~0.3 Mpa higher than the exhaust pressure. 7) After the liquid level in the ammonia storage tank reaches 50%, open the inlet and outlet isolation valves of LIC-1502, and activate LIC-1502 to supply ammonia to the ammonia sphere tank. 8) Observe whether the unit is operating normally; if so, continue to increase the load to the normal energy level, and then move the energy switch to the stop position. 2. Shutdown: 1) Reduce the liquid level of LIC-1502 to 50%. 2) Turn the energy regulation switch to the under-load position, close the LIC-1502 control valve, and simultaneously reduce the suction load stop valve. 3) When the energy indicator drops to 0%, press the compressor stop button and close the suction shut-off valve. 4) After the compressor stops running, press the oil pump stop button. 5) Close all stop valves on the air separator. 6) Close the ammonia and liquid ammonia shut-off valves connected to the ammonia ball tank; after depressurizing the small chiller, close its outlet valve. 7) Close or keep the circulating water isolation valve open as appropriate. 8) Cut off the power supply to the unit.