Information on propylene refrigeration compressors
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There’s a lot of information on ammonia compressors on the forum, but none on propylene ones. Who has information on propylene refrigeration compressors? It’s been passed up for everyone to share. Thank you
We purchased a compressor cooled by propylene; it hasn’t arrived yet. It uses a twin-screw oil injection system for cooling, but since the equipment isn’t here yet, there are no accompanying documents.
Yes, I also urgently need materials on this topic to study*.
This is the information regarding the chillers in my workshop; I hope it will be useful to you. Section 2: Refrigeration Units C-401A/B. 1. Introduction to the role of refrigeration units C-401A/B in production. The main product of the acrylonitrile production process, acrylonitrile, as well as by-products such as hydrocyanic acid, have a strong tendency to polymerize. Under conditions of high temperature or when the system becomes alkaline, they polymerize into larger organic molecules; sometimes this leads to explosive polymerization, which can cause severe damage to pipelines and equipment, resulting in serious equipment failures and safety accidents. To prevent such polymerization, the following methods are employed: one of them is to add sulfuric acid in the synthesis and quenching tower (T-101) to neutralize excess ammonia, thereby adjusting the pH value； The second step is to cool the reaction products to a temperature below that of polymerization; the cooling medium used is an ethylene glycol solution with a concentration of 25% at a temperature of 0–3°C. The cooling capacity for the ethylene glycol solution is provided by the chiller C-401A/B. The simple cooling process is as follows: 10–14°C ethylene glycol solution → salt water pump P-401 → cooled in the chiller evaporator to 0–3°C → heat is transferred to the end users, raising their temperature to 10–14°C → salt water tank V-401 → salt water pump P-401. II. Refrigeration principle and process of the refrigeration units C-401A/B. Simply put, a refrigeration unit uses a compressor to cyclically compress the refrigerant; this refrigerant alternates between liquid and gas states, and during the transition from liquid to gas it absorbs a large amount of heat, thereby cooling the coolant (ethylene glycol aqueous solution) and enabling the entire refrigeration process. The refrigeration unit consists of the following main components: a drive mechanical steam turbine, a centrifugal compressor, an economizer, an evaporator, and a condenser. A certain amount of liquid propylene is filled in the shell sides of the evaporator and the condenser. Saltwater is passed through the tube side of the evaporator, while circulating water is used in the tube side of the condenser, after which the compressor is started up. Some of the propylene evaporates into a gaseous state, enters the compressor where it is compressed to increase its temperature and pressure. It is then sent to the condenser, where it is cooled by circulating water; after cooling, it returns to a liquid state. Some of this liquid propylene passes through a throttling device and enters the economizer, where its pressure is reduced, causing it to vaporize and enter the fourth and second stages of the compressor for further compression. When the propylene in the evaporator turns into a gas, it absorbs a large amount of heat, and this heat is absorbed from the ethylene glycol solution inside the evaporator tubes. The above process thus achieves the refrigeration process. III. Introduction to Compressor C-401
1. Main technical parameters:
Type: Centrifugal
Model: M426B
Stage count: 4 stages
Shaft power: 600 KW
Normal speed: 10,800 rpm
Flow rate: 30,594 kg/h
Medium pressure: Inlet/outlet – 0.44/1.69 MPa
Medium temperature: Inlet/outlet – –2.78/60.6 °C
Cooling capacity: 1.95 million kcal/h per unit
Refrigerant: Propylene
First critical speed: 27,269 rpm
2. Unit interlocks and alarms (including the turbine):
Serial No. | Parameter Code | Name | Alarm Value | Interlock Value
1 | PS-001 | Saltwater outlet temperature | –3 °C
2 | PS-054 | Low turbine lubricating oil pressure | 0.06 MPa | 0.045 MPa
3 | PS-012 | High condenser pressure | 1.85 MPa
4 | PS-017 | Low evaporator pressure | 0.37 MPa
5 | PS-023-1 | Low oil pressure difference in compressor | 0.33 MPa | 0.28 MPa
6 | TRA-100-2 | High temperature of compressor thrust bearing | 75 °C
7 | PS-01 | Low blowing pressure of positive pressure ventilation fan | 30 mmHg
8 | PS-047 | High turbine discharge pressure | 0.38 MPa
9 | TRA-100-4 | High temperature of turbine thrust shaft | 75 °C
10 | TRA-100-5 | High temperature of Turbine No. 1 bearing | 75 °C
11 | TRA-100-6 | High temperature of Turbine No. 2 bearing | 75 °C
12 | LS-060 | Low liquid level in turbine oil tank | 160 mm
13 | TRA-100-1 | High temperature of oil supplied to compressor | 60 °C
14 | TRA-100-3 | High temperature of oil returning from compressor’s main bearing | 60 °C
15 | LS-034 | Low liquid level alarm in compressor oil tank | 90.5 mm
16 | VIA-110-1 | High compressor vibration alarm | 9 mm/s
17 | *A-120-1 | High compressor shaft displacement alarm | ±0.3 mm
18 | *A-110-2 | High turbine vibration alarm | 7 mm/s
19 | VIA-120-2 | High turbine shaft displacement alarm | ±0.6 mm
20 | TS-010 | High compressor exhaust temperature alarm | 100 °C
21 | Emergency stop button
3. Oil system:
The lubricating oil system consists of a main oil pump, an auxiliary oil pump, oil filters, an oil cooler, an oil tank, and various oil pipelines. Forced lubrication is required at the four main lubrication points of the compressor, namely: the thrust bearing, the main bearing on the inlet side, the main bearing on the outlet side, and the shaft seal. The main oil pump is a centrifugal pump designed by Mitsubishi York, assembled with bolts and driven directly by the rotor shaft. The oil from the oil filter follows the following paths: a. Part of it flows to the main bearings and thrust bearings at the outlet end. b. Another portion flows to the main bearings and shaft seals at the inlet end of the compressor. At the outlet end, the lubricating oil from the oil filter enters the passages on the side of the oil tank housing, and then flows into the gap around the shaft between the main bearings and the thrust bearings. From this space, part of the oil flows toward the impeller via the main bearings, while another part flows in the direction of the oil pump (located between the shaft and the thrust bearings) to reach the load-bearing surface of the thrust bearings. The lubricating oil flows from the main bearing at the outlet end to the impeller, entering the space within the oil tank and the seal ring housing; this oil is discharged into the oil tank. The oil seal at the outlet end is designed in such a way that some of the gas leaking from the balance disk can enter the oil tank, with the pressure in the oil tank being equal to the pressure at the inlet of the low-pressure impeller. The oil that lubricates the thrust surfaces (the inner surface of the oil pump and the outer surface of the thrust bearings) flows out through the oil cooler, and is then pumped back to the inlet of the lubricating oil pump via a jet pump. While this portion of oil passes through the jet pump, another portion of oil from the tank flows to the inlet of the compressor lubrication pump. The oil coming from the oil filter and flowing to the compressor inlet goes into the bearing housing, and then passes through channels to reach the annular space surrounding the main bearings at the inlet. The main bearing has radial through-holes that allow lubricating oil to flow to the bearing surfaces; this oil flows through the main bearing and then returns to the oil tank via external return lines. All the oil that flows to the main bearing at the inlet end overflows into the shaft seal area; starting from there, this oil returns to the shaft seal gas-liquid separator through a check valve. A small amount of oil that leaks to the atmospheric side of the shaft seal, under the effect of its own gravity, flows into the gas-liquid separator located at the bottom of the compressor housing. 4. Refill of the refrigerant: The refrigeration units C-401A/B use propylene as a refrigerant, and the process is generally carried out as follows: 1) Turn on the oil heater to raise the oil temperature to between 65–75°C. 2) Inspect the brine system, start the brine pump P-401, and ensure that brine can be continuously discharged from the evaporator’s vent (indicating that the gas in the tube side has been completely removed). 3) Circulate water through the condenser and open the vent for exhaust. 4) Fill the shell-side systems of the evaporator and condenser with nitrogen, bring the pressure to 0.7–0.8 MPa and then vent it to reduce the pressure as much as possible; after that, fill it with nitrogen again, repeating this process at least three times. After that, the laboratory technician is contacted to measure the oxygen level in the system; when the oxygen content drops below 0.5%, the conditions for filling with propylene are met, at which point nitrogen is used to maintain pressure. 5) Contact the dispatching department to receive polypropylene. 6) Open the DN25 valve for propylene at the tank area, then open the DN50 valve on the small platform on the first floor of the air-cooling plant, and finally open the DN20 propylene valve at the bottom of the evaporator. At this point, propylene enters the shell-side systems of the evaporator and condenser. 7) Check whether all nitrogen valves are closed. 8) When the pressure of propylene reaches approximately 0.7–0.8 MPa, it is released to a flare for combustion in order to displace the nitrogen in the system; this process should be repeated at least three times to ensure complete displacement. Finally, the propylene pressure is raised to around 1.0 MPa in preparation for operation. 5. Introduction to oil circuit system equipment 1) Main oil pump: It is a centrifugal pump driven directly by the compressor. In the event that the compressor stops due to an electrical fault and the auxiliary oil pump cannot start, it provides lubrication to prevent bearing failures. 2) Auxiliary oil pump: It is a gear pump driven by an electric motor. When starting and stopping the freezer, this pump is used; manual and automatic operation can be selected. During the operation of the freezer, it remains in the automatic mode, and it starts up and comes into operation immediately when the oil pressure (pressure difference) falls below the set value. 3) Thrust pump: This is a centrifugal pump that forms an integral structure with the main oil pump; it takes advantage of thrust bearings for oil discharge in order to provide high-pressure lubricating oil for driving the jet pump. 4) Jet pump: Utilizes the high-pressure oil supplied by the thrust pump, and through the action of a ejector, transfers the oil in the fuel tank to the main fuel pump. 5) Oil cooler: Used to cool the lubricating oil and remove the heat generated by friction in the bearings and mechanical seals. 6) Oil filter: It functions to remove dust from the oil. A paper core with a filtration precision of 10 microns is used, and the paper core should be replaced when the lubricating oil pressure drops to 120% of the initial pressure. 7) Oil heater: It prevents the coolant in the lubricating oil from dissolving in the oil when the refrigeration unit stops operating. When the chiller stops operating, steam heating (using steam at a low pressure of 0.3 MPa) is employed to maintain the oil tank temperature at 65–75°C. IV. Introduction to the Chiller Turbine 1. Technical Parameters Model: EM3B4 Stage count: 4 Steam pressure: Inlet/Outlet 4.12/0.317 MPa Steam temperature: Inlet/Outlet 343/145°C Rated inlet steam flow: 7.5 t/h Rated speed: 10,800 rpm Speed at trip: 12,474 ± 113 rpm Speed control range of the governor: 8,640–11,340 rpm First critical speed: 4,556 rpm Second critical speed: 15,188 rpm 2. Introduction to the Lubricating Oil System The turbine lubricating oil is primarily used for the main bearings, thrust bearings, and the governor. The lubricating oil is divided into two systems: the lubricating oil circuit and the control oil circuit. The power source for both systems comes from an oil pump, which is a gear pump. Lubricating oil section: During normal operation, the oil supplied by the lubricating oil system is sent to the main bearings, thrust bearings, and other components via an oil cooler and a pressure reducing valve. The pressure relief valve in the bearing oil circuit is set at around 0.1 MPa. There must be an adequate amount of lubricating oil available for the turbine, so that when it is operating at full speed, the oil level indicated by the oil gauge remains within the permitted limits. Although there is only an oil filter in the oil circuit, as a protective measure when filling the fuel tank with oil, it is still necessary to use a regulating screen or filter cloth to filter the oil. To keep the oil temperature leaving the oil cooler below 50°C, it is necessary to adjust the water flow rate in the oil cooler. Although the bearing temperature changes depending on various operating and environmental conditions, under normal circumstances, an oil temperature at the bearing outlet of 60–70°C is generally considered practical. When starting up the turbine, do not turn on the circulating water for the cooler until the oil temperature reaches the aforementioned specified value. Control oil circuit (shut-down oil circuit): The control oil is supplied directly from the lubricating oil line via a orifice plate. Under normal operation, if there is virtually no oil flow (except for leaks), the system pressure is almost equal to the lubricating oil pressure. Between the turbine protection devices, the trip oil system acts as a static pressure connection or interlocking device; the activation of any one of these protection devices causes the trip oil to be released, which in turn activates all the turbine valves through the various control mechanisms. This task can only be carried out while the oil pump is running and all protective mechanisms are in their reset position. Under normal circumstances, the jump-out fuel is referred to as the automatic stop fuel. Under normal operating conditions, any of the following faults can cause the trip oil to be discharged. a. Turbine overspeed trip b. Manual activation of the trip device c. Solenoid valve trip V. Turbine overspeed trip test 1. Introduction to the overspeed trip system: When the turbine reaches a speed of 110% ± 1% of its maximum continuous operating speed for some reason, the overspeed trip mechanism is activated in order to prevent the rotor from breaking due to excessive centrifugal force. The overspeed ejector mechanism consists of an ejector counterweight, a compressor spring, and an ejector control lever. The jump-off balance weight and spring are assembled in the transverse hole of the rotor shaft. The center of gravity of the car-jumping counterweight is slightly ahead of the rotor shaft; it is positioned and fixed there using a compression spring and adjustment threads. The centrifugal force acting on the jump-balancing weight is controlled by the spring compression force, the magnitude of which is adjusted by the rotating adjustment screw. If the speed increases to the ejection speed, the ejection counterweight is flung out and hits the ejection control lever, which rotates around its axis, thereby closing the ejection valve. The oil pressure acting on the trip valve is discharged through the gap in the main valve seat of the trip device, thereby allowing the automatic stop oil surrounding the valve seat to be released. The automatic stop prevents oil from flowing directly to the trip piston of the main stop valve. If this oil pressure disappears, it is the operating lubricating oil being discharged from the main stop valve. The spring force activated the stopper, closing the stop valve; as a result, both the main control valve and the main stop valve were closed. Thus, this turbine trip system is designed as a double-check valve. After the jump-off system is turned off, in order to readjust the speed of the jump-off mechanism, this must be done after the turbine speed drops to the lowest speed set by the governor. Chiller turbine overspeed trip scheme. Test steps for the overspeed trip of the chiller turbine CT-401A/B: 1) Ensure that the utility supply is in place, and verify that all parameters of the 4.0 MPa high-pressure steam are within acceptable limits: pressure of 4.12 MPa, temperature of 343°C, with an external flow rate of 5 tons per hour. 2) The maintenance personnel disconnected the couplings of the CT-401A/B units; after confirming that the shaft could rotate freely, they restored the protective covers. 3) After checking to confirm that there are no issues with the oil circuit, start the auxiliary oil pumps P-404A/B according to the steps; the oil circuit system will then begin to operate. At this point, the main things to check are the oil pressure level and the performance of the auxiliary oil pumps. Check for leaks at the same time. 4) Warm up CT-401A/B step by step until they are in normal operating condition; pay attention to steam drainage during this process, and also keep in mind the need to rotate the turbines. 5) Contact the instrumentation to short-circuit the interlock of the compressor that cannot be reset temporarily, and ensure that the turbine is ready for operation. 6) Start CT-401A/B according to the startup procedures, use the start-up handwheel to increase the turbine speed to 500–1000 rpm, and conduct a thorough inspection of the unit to ensure that all parameters are within the specified ranges: no abnormal noises ； Bearing displacement is less than ±0.6mm ； Shaft vibration 3.5 kg/cm2 (PDI-023) ； ⑤Adjust the turbine oil supply temperature to 36~46℃ ； ⑥Adjust the turbine oil supply pressure to 1.0~1.2 kg/cm2 (PG-056) ； (4) End of operation: ① Close each drain valve of the turbine ； ②Slowly open the middle exhaust valve, adjusting its opening degree so that the float ball of the economizer can function properly. 4. Operational preventive measures. ①Check each attachment for vibration and noise ； ②Check the temperature, pressure, and level of the lubricating oil ； ③Check whether the cooling water temperature is below the specified value ； ④Check the main steam and backpressure steam temperatures of the turbine ； ⑤Check the saltwater temperature and the downward trend in evaporator pressure ； ⑥Check the working condition of the float ball ； ⑦Check the evaporation status. VII. Chiller shutdown procedure 1. Confirm with the process team that it is safe to stop the chiller from operating ； 2. Use the regulator knob to reduce the turbine speed to the regulator’s lowest speed of 8640 rpm ； 3. Automatic start of auxiliary oil pump ； 4. Gradually close the main air isolation valve completely by turning its handle to stop the turbine ； 5. Stop the circulating water of the oil cooler ； 6. Close the turbine exhaust isolation valve, open the front and rear drain valves to drain completely, then close them ； 7. Stop the driving steam to the pressure gland-sealed condenser ； 8. Close the main steam isolation valve of the turbine, open the upstream and downstream drain valves to drain all liquid, then close them ； 9. Open the main air shut-off valve, the discharge valve of the housing, and the discharge valve of the steam chamber; close them after all liquid has been drained ； 10. Set PRV to 0% ； 11. Turn HC-001 off to over 50% ； 12. Maintenance after shutdown: ① The turbine auxiliary oil pump shuts down automatically after 8 hours; it can be started manually as appropriate, and the pump stops once the bearings have cooled down ； ②Turn the machine every 2 hours ； ③Drain the standing water. 13. Propylene emissions: ①Close the circulating water valves of condensers E-401A/B ； ②Contact the control room to schedule propylene discharge ； ③Open the safety valve bypass valve of evaporator E-402A/B to discharge to the flare ； ④Open the safety valve bypass valve of condenser E-401A/B to discharge to the flare ； ⑤After the discharge is complete, close the E-401A/B and E-402A/B safety valve bypass valves ； ⑥Open the nitrogen valve and fill with nitrogen ； ⑦Continue to arrange the torches, repeat 3 times ； ⑧Reset of nitrogen filling valve and safety valve bypass valve ； ⑨The oxygen level tested was within acceptable limits. 14. Brine discharge: ① Stop brine pumps P-401A/B/S ； ②Close the brine valve on the tube side of evaporator E-402A/B ； ③Lead tape from the tube side drain of evaporator E-402A/B to brine tank V-401 ； ④Open the vent valve on the tube side of evaporator E-402A/B ； ⑤Open the shell-side drain valve of evaporator E-402A/B. 15. Pressurizing the shell side of condensers E-401A/B: ① Close the circulating water valves on the tube side of E-401A/B; ② Open the vent valve and drain valve on the tube side to drain water ； ③Remove the cover ； ④When pressurizing the shell side, check for leaks from the tube sheet (install blind flanges before pressurization). 16. Pressurizing the shell side of evaporators E-402A/B: ① Close the brine valves on the tube side of E-402A/B ； ②Open the pipe bank vent valve and drain valve to discharge brine ； ③Remove the cover ； ④When pressurizing the tube sheet, check for leaks from the tube sheet (install blind flanges before pressurization). VIII. Emergency Plan for Chiller Operation Incidents 1. What to do if a power outage causes the chiller turbine CT-401 to stop operating? Handling method: (1) Reduce the speed regulator to the lowest speed ； (2) If the turbine load valve is open, close this valve ； (3) Reset the main air shut-off valve ； (4) Open the low-pressure steam valve on the heaters of tanks C-401A/B to heat the tanks to 65~75℃ ； (5) Open all drain valves of the unit ； (6) Open the drive steam valve for the gland-sealed condenser ； (7) Open all drain valves on the main steam line ； (8) Open all drain valves on the backpressure steam line ； (9) If power supply has not been restored, close the main steam line isolation valve and the backpressure steam isolation valve ； (10) After power is restored, start CT-401A/B by following the startup procedures for CT-401A/B. 2. Low oil pressure in chillers C-401A/B. Cause: (1) Clogged oil filter ； (2) Bearing wear ； (3) The pressure gauge is broken and gives inaccurate readings ； (4) Insufficient lubricating oil ； (5) Due to a large amount of propylene dissolving in the oil ； (6) Oil pump failure. Treatment method: (1) Clean the oil filter (replace components) ； (2) Stop the machine to adjust the bearing clearance ； (3) Check and service the pressure gauge ； (4) Refuel ； (5) Increase oil temperature by supplying oil or reduce the cooling water flow in the oil cooler ； (6) Service the oil pump. 3. Oil leakage from the oil tanks of chillers C-401A/B, with poor oil level control. Phenomenon: The oil level in the tanks is not well controlled, and it drops rapidly after refueling. Reason: (1) The pressure of the sealing gas PG-032 is low, allowing oil to seep into the compressor through the seal and eventually accumulate at the bottom of the evaporator ； (2) Seal failure, leakage ； (3) Severe leakage in the oil pipeline ； (4) The heat exchange tubes of the oil cooler are leaking, allowing oil to enter the circulating water. Treatment method: (1) Adjust valve VL-120 so that the pressure of PG032 is 0.7~1.0 kg/cm2 higher than the pressure PG028 in the fuel tank ； (2) Stop the machine to replace the seal ； (3) Shut down to address oil pipeline leaks ； (4) Switch the oil cooler to the other unit, remove the original one and use the oil cooler head instead, then inspect the tube bundles. 4. Abnormal loss of propylene in evaporators E-402A/B. Phenomenon: After propylene is injected into evaporators E-402A/B, the liquid level drops rapidly, indicating a propylene leak. Reason: (1) Internal leakage in the safety valves at the tops of evaporators E-402A/B and condensers E-401A/B, resulting in propylene loss through the flare line ； (2) The relief valve bypass valves for evaporators E-402A/B and condensers E-401A/B are not properly closed or there is internal leakage in the valves ； (3) Severe leakage from the gasket of the sight glass or flange ； (4) The heat exchange tubes in condensers E-401A/B are leaking, causing propylene to leak into the circulating water. Treatment method: (1) Take preventive measures by closing the shut-off valves in front of the safety valves on the tops of evaporators E-402A/B and condensers E-401A/B, and address the safety valves ； (2) Close the safety valve bypass valve or install a blind flange ； (3) Addressing leaks in sight glasses or flange gaskets ； (4) Shut down for maintenance of condensers E-401A/B. 5. If the circulating water is stopped, how should the chillers C-401A/B be handled? Handling method: (1) If the water supply is interrupted for an extended period, shutdown procedures should be followed ； (2) If recovery is possible in a short period of time, appropriate adjustments can be made to ensure the proper operation of the unit ； (3) Start HC-001 to cause the propylene in condensers E-401A/B to reflux, thereby reducing the pressure within those condensers ； (4) Closely monitor the bearing temperature rise; if it exceeds the limit value, initiate an emergency shutdown ； (5) Cool the surface of the oil cooler using other water (such as fresh water). 6. The liquid level in saltwater tank V-401 is dropping abnormally. Phenomenon: The liquid level in saltwater tank V-401 drops rapidly and cannot be maintained. Reason: (1) The drain valve on the inlet line of the salt water pump P-401 was not closed properly or there was internal leakage in the valve, resulting in loss of fluid through the drain ； (2) Tube leakage in the heat exchanger (brine user), with brine leaking into other fluids ； (3) Leakage in the tubes of evaporator E-402 ； (4) There is a leak in the drain valve of the brine circuit. Treatment method: (1) Check and close the drain valve on the inlet line of the salt water pump P-401; if there is internal leakage, replace the valve ； (2) Inspect each heat exchange user; if a leak is found, isolate it and address the tube bundle ； (3) Stop work to handle the tubes in E-402. (4) Check the brine flow and close the drain valve (tightly). 7. The pressure of condensers E-401A/B is abnormally high. Phenomenon: The condenser pressure is high, approaching the trip value of 1.85 Mpa. Reason: (1) High circulating water temperature ； (2) The heat exchange efficiency is extremely poor ； (3) The chiller load is too high. Solution: (1) Contact the dispatch team to lower the temperature of the circulating water ； (2) After adjustment proves ineffective, shut down the condenser tubes ； (3) Reduce chiller load ； (4) The most effective adjustment method is to turn on HC-001 to allow the propylene gas to flow back, thereby reducing the pressure in the condenser. IX. Common faults of ice machines and their solutions 1. Abnormal increase in condenser pressure Reasons: 1) Gas remains in the condenser and has not been completely removed. 2) The condenser tubes are severely blocked and fouled, resulting in insufficient flow of circulating cooling water. 3) There are impurities in the circulating cooling water, which block the inlet of the circulating water. 4) The flow rate of the circulating cooling water is insufficient. 5) The temperature of the circulating cooling water is too high, exceeding 30°C. 2. The internal ribs of the gasket at the end cap of the condenser were not installed, resulting in short-circuit operation of the circulating water. Treatment method: 1) Discharge from the condenser tube side. 2) Shutdown to clean the condenser tubes of the chiller (high-pressure water cleaning). 3) Stop the machine, open the head to inspect and clean it. 4) Check and adjust the circulating water flow rate. 5) Contact the dispatching team to lower the circulating water temperature. 6) Shut down the machine and open the condenser for inspection. 7) Remove non-condensable gases from the propylene to obtain polypropylene-grade propylene. 3. Low evaporator pressure. Cause: Insufficient amount of refrigerant. The refrigerant is too dirty. The float valve is defective. The evaporator tubes are blocked. The PRV opening is too large. Solution: Fill with refrigerant. Purify refrigerant agents. Open the float valve by hand. Park the vehicle and clean the evaporator tubes. Adjust the opening of the PRV and the opening of the HC-001 valve. 4. Abnormal rise in evaporator pressure: Refrigerant liquid is drawn into the compressor (too much propylene). The opening degree of HC-001 is too fast and too large. The condenser pressure is high. The unit load is too high. Solution: Release an appropriate amount of propylene. Slowly adjust the opening degree of the HC-001 valve. Inspect and service the condenser. Adjust the unit load. 5. Significant drop in compressor oil pressure. Cause: Excessive propylene dissolved in the oil, resulting in a decrease in oil viscosity. The oil filter screen is severely clogged. The oil pump is faulty. The oil reserve is too low. There is a problem with the oil pressure gauge. Solution: Increase the temperature of the condenser oil to reduce the amount of propylene dissolved in it. Clean and replace the oil filter element. Check and address the oil pump failure. Check the supplementary condensate oil. Check the treatment oil pressure gauge. 6. Unstable compressor oil pressure, fluctuating up and down. Cause: There is a problem with the oil pressure gauge. Propylene gas is mixed in the oil pressure guiding pipe. There is a problem with the control valve. Solution: Check the oil pressure gauge for processing. Exclude propylene gas. Inspect and adjust the cleaning control valve components. 7. High compressor bearing temperature; low cooling water flow in the oil cooler. The oil cooler tubes are blocked. The lubricating oil is dirty. The bearing is damaged. The oil circulation volume is insufficient. The temperature of the cooling water in the oil cooler is high. Solution: Adjust and increase the water flow rate in the oil cooler. Inspect and clean the oil cooler. Replace the lubricating oil. Check the bearing wear. Check and adjust the fuel tank level. Contact the dispatch team to lower the circulating water temperature. 8. Severe vibration in the unit. Cause: Poor alignment of the unit. The wear gap of the bearing has increased. The labyrinth seal makes contact with the rotor. Liquid present at the compressor inlet. Low load, surge. Other abnormal conditions. Solution: Shut down the machine and realign it. Shut down the machine and check the bearing wear. Adjust the labyrinth seal and rotor clearance. Check the evaporator liquid level and discharge some propylene. Increase the load. Thoroughly inspect the evaporator, condenser, oil circuit, etc., for any abnormalities. 9. Low turbine speed. Cause: Excessive load on the unit. Steam flow is low. The main steam temperature is low. Main steam pressure is low. The backpressure steam pressure is high. Solution: Adjust the load of the speed-regulating unit. Increasing the main steam flow allows the load to be increased appropriately. Increase the main steam temperature. Increase the main steam pressure. Reduce the backpressure steam pressure. 10. The unit cannot start. Reason: The safety device is not connected. There is an alarm or interlock that has not been reset. Instrument failure. Solution: Check if there are any issues with the safety device. Check for any alarms and ensure that interlocks have not been reset. Check the instrument issues. 11. The compressor auxiliary oil pump cannot refill oil. Reason: The pressure at the pump outlet is too low, below the pressure in the oil tank. There is gas inside the pump. The gear is damaged. The oil flow path is not established. There is too little oil in the oil tank. The inhalation tubing is blocked. Solution: Adjust the outlet pressure of the gear pump. Ensure thorough exhaust. Inspect and repair the gear. Check whether the process is correct. Refilling the oil tank. Inspect and clean the pipeline.
1. Main technical parameters:
Type: Centrifugal
Model: M426B
Stage count: 4 stages
Shaft power: 600 KW
Normal speed: 10,800 rpm
Flow rate: 30,594 kg/h
Medium pressure: Inlet/outlet – 0.44/1.69 MPa
Medium temperature: Inlet/outlet – –2.78/60.6 °C
Cooling capacity: 1.95 million kcal/h per unit
Refrigerant: Propylene
First critical speed: 27,269 rpm
2. Unit interlocks and alarms (including the turbine):
Serial No. | Parameter Code | Name | Alarm Value | Interlock Value
1 | PS-001 | Saltwater outlet temperature | –3 °C
2 | PS-054 | Low turbine lubricating oil pressure | 0.06 MPa | 0.045 MPa
3 | PS-012 | High condenser pressure | 1.85 MPa
4 | PS-017 | Low evaporator pressure | 0.37 MPa
5 | PS-023-1 | Low oil pressure difference in compressor | 0.33 MPa | 0.28 MPa
6 | TRA-100-2 | High temperature of compressor thrust bearing | 75 °C
7 | PS-01 | Low blowing pressure of positive pressure ventilation fan | 30 mmHg
8 | PS-047 | High turbine discharge pressure | 0.38 MPa
9 | TRA-100-4 | High temperature of turbine thrust shaft | 75 °C
10 | TRA-100-5 | High temperature of Turbine No. 1 bearing | 75 °C
11 | TRA-100-6 | High temperature of Turbine No. 2 bearing | 75 °C
12 | LS-060 | Low liquid level in turbine oil tank | 160 mm
13 | TRA-100-1 | High temperature of oil supplied to compressor | 60 °C
14 | TRA-100-3 | High temperature of oil returning from compressor’s main bearing | 60 °C
15 | LS-034 | Low liquid level alarm in compressor oil tank | 90.5 mm
16 | VIA-110-1 | High compressor vibration alarm | 9 mm/s
17 | *A-120-1 | High compressor shaft displacement alarm | ±0.3 mm
18 | *A-110-2 | High turbine vibration alarm | 7 mm/s
19 | VIA-120-2 | High turbine shaft displacement alarm | ±0.6 mm
20 | TS-010 | High compressor exhaust temperature alarm | 100 °C
21 | Emergency stop button
3. Oil system:
The lubricating oil system consists of a main oil pump, an auxiliary oil pump, oil filters, an oil cooler, an oil tank, and various oil pipelines. Forced lubrication is required at the four main lubrication points of the compressor, namely: the thrust bearing, the main bearing on the inlet side, the main bearing on the outlet side, and the shaft seal. The main oil pump is a centrifugal pump designed by Mitsubishi York, assembled with bolts and driven directly by the rotor shaft. The oil from the oil filter follows the following paths: a. Part of it flows to the main bearings and thrust bearings at the outlet end. b. Another portion flows to the main bearings and shaft seals at the inlet end of the compressor. At the outlet end, the lubricating oil from the oil filter enters the passages on the side of the oil tank housing, and then flows into the gap around the shaft between the main bearings and the thrust bearings. From this space, part of the oil flows toward the impeller via the main bearings, while another part flows in the direction of the oil pump (located between the shaft and the thrust bearings) to reach the load-bearing surface of the thrust bearings. The lubricating oil flows from the main bearing at the outlet end to the impeller, entering the space within the oil tank and the seal ring housing; this oil is discharged into the oil tank. The oil seal at the outlet end is designed in such a way that some of the gas leaking from the balance disk can enter the oil tank, with the pressure in the oil tank being equal to the pressure at the inlet of the low-pressure impeller. The oil that lubricates the thrust surfaces (the inner surface of the oil pump and the outer surface of the thrust bearings) flows out through the oil cooler, and is then pumped back to the inlet of the lubricating oil pump via a jet pump. While this portion of oil passes through the jet pump, another portion of oil from the tank flows to the inlet of the compressor lubrication pump. The oil coming from the oil filter and flowing to the compressor inlet goes into the bearing housing, and then passes through channels to reach the annular space surrounding the main bearings at the inlet. The main bearing has radial through-holes that allow lubricating oil to flow to the bearing surfaces; this oil flows through the main bearing and then returns to the oil tank via external return lines. All the oil that flows to the main bearing at the inlet end overflows into the shaft seal area; starting from there, this oil returns to the shaft seal gas-liquid separator through a check valve. A small amount of oil that leaks to the atmospheric side of the shaft seal, under the effect of its own gravity, flows into the gas-liquid separator located at the bottom of the compressor housing. 4. Refill of the refrigerant: The refrigeration units C-401A/B use propylene as a refrigerant, and the process is generally carried out as follows: 1) Turn on the oil heater to raise the oil temperature to between 65–75°C. 2) Inspect the brine system, start the brine pump P-401, and ensure that brine can be continuously discharged from the evaporator’s vent (indicating that the gas in the tube side has been completely removed). 3) Circulate water through the condenser and open the vent for exhaust. 4) Fill the shell-side systems of the evaporator and condenser with nitrogen, bring the pressure to 0.7–0.8 MPa and then vent it to reduce the pressure as much as possible; after that, fill it with nitrogen again, repeating this process at least three times. After that, the laboratory technician is contacted to measure the oxygen level in the system; when the oxygen content drops below 0.5%, the conditions for filling with propylene are met, at which point nitrogen is used to maintain pressure. 5) Contact the dispatching department to receive polypropylene. 6) Open the DN25 valve for propylene at the tank area, then open the DN50 valve on the small platform on the first floor of the air-cooling plant, and finally open the DN20 propylene valve at the bottom of the evaporator. At this point, propylene enters the shell-side systems of the evaporator and condenser. 7) Check whether all nitrogen valves are closed. 8) When the pressure of propylene reaches approximately 0.7–0.8 MPa, it is released to a flare for combustion in order to displace the nitrogen in the system; this process should be repeated at least three times to ensure complete displacement. Finally, the propylene pressure is raised to around 1.0 MPa in preparation for operation. 5. Introduction to oil circuit system equipment 1) Main oil pump: It is a centrifugal pump driven directly by the compressor. In the event that the compressor stops due to an electrical fault and the auxiliary oil pump cannot start, it provides lubrication to prevent bearing failures. 2) Auxiliary oil pump: It is a gear pump driven by an electric motor. When starting and stopping the freezer, this pump is used; manual and automatic operation can be selected. During the operation of the freezer, it remains in the automatic mode, and it starts up and comes into operation immediately when the oil pressure (pressure difference) falls below the set value. 3) Thrust pump: This is a centrifugal pump that forms an integral structure with the main oil pump; it takes advantage of thrust bearings for oil discharge in order to provide high-pressure lubricating oil for driving the jet pump. 4) Jet pump: Utilizes the high-pressure oil supplied by the thrust pump, and through the action of a ejector, transfers the oil in the fuel tank to the main fuel pump. 5) Oil cooler: Used to cool the lubricating oil and remove the heat generated by friction in the bearings and mechanical seals. 6) Oil filter: It functions to remove dust from the oil. A paper core with a filtration precision of 10 microns is used, and the paper core should be replaced when the lubricating oil pressure drops to 120% of the initial pressure. 7) Oil heater: It prevents the coolant in the lubricating oil from dissolving in the oil when the refrigeration unit stops operating. When the chiller stops operating, steam heating (using steam at a low pressure of 0.3 MPa) is employed to maintain the oil tank temperature at 65–75°C. IV. Introduction to the Chiller Turbine 1. Technical Parameters Model: EM3B4 Stage count: 4 Steam pressure: Inlet/Outlet 4.12/0.317 MPa Steam temperature: Inlet/Outlet 343/145°C Rated inlet steam flow: 7.5 t/h Rated speed: 10,800 rpm Speed at trip: 12,474 ± 113 rpm Speed control range of the governor: 8,640–11,340 rpm First critical speed: 4,556 rpm Second critical speed: 15,188 rpm 2. Introduction to the Lubricating Oil System The turbine lubricating oil is primarily used for the main bearings, thrust bearings, and the governor. The lubricating oil is divided into two systems: the lubricating oil circuit and the control oil circuit. The power source for both systems comes from an oil pump, which is a gear pump. Lubricating oil section: During normal operation, the oil supplied by the lubricating oil system is sent to the main bearings, thrust bearings, and other components via an oil cooler and a pressure reducing valve. The pressure relief valve in the bearing oil circuit is set at around 0.1 MPa. There must be an adequate amount of lubricating oil available for the turbine, so that when it is operating at full speed, the oil level indicated by the oil gauge remains within the permitted limits. Although there is only an oil filter in the oil circuit, as a protective measure when filling the fuel tank with oil, it is still necessary to use a regulating screen or filter cloth to filter the oil. To keep the oil temperature leaving the oil cooler below 50°C, it is necessary to adjust the water flow rate in the oil cooler. Although the bearing temperature changes depending on various operating and environmental conditions, under normal circumstances, an oil temperature at the bearing outlet of 60–70°C is generally considered practical. When starting up the turbine, do not turn on the circulating water for the cooler until the oil temperature reaches the aforementioned specified value. Control oil circuit (shut-down oil circuit): The control oil is supplied directly from the lubricating oil line via a orifice plate. Under normal operation, if there is virtually no oil flow (except for leaks), the system pressure is almost equal to the lubricating oil pressure. Between the turbine protection devices, the trip oil system acts as a static pressure connection or interlocking device; the activation of any one of these protection devices causes the trip oil to be released, which in turn activates all the turbine valves through the various control mechanisms. This task can only be carried out while the oil pump is running and all protective mechanisms are in their reset position. Under normal circumstances, the jump-out fuel is referred to as the automatic stop fuel. Under normal operating conditions, any of the following faults can cause the trip oil to be discharged. a. Turbine overspeed trip b. Manual activation of the trip device c. Solenoid valve trip V. Turbine overspeed trip test 1. Introduction to the overspeed trip system: When the turbine reaches a speed of 110% ± 1% of its maximum continuous operating speed for some reason, the overspeed trip mechanism is activated in order to prevent the rotor from breaking due to excessive centrifugal force. The overspeed ejector mechanism consists of an ejector counterweight, a compressor spring, and an ejector control lever. The jump-off balance weight and spring are assembled in the transverse hole of the rotor shaft. The center of gravity of the car-jumping counterweight is slightly ahead of the rotor shaft; it is positioned and fixed there using a compression spring and adjustment threads. The centrifugal force acting on the jump-balancing weight is controlled by the spring compression force, the magnitude of which is adjusted by the rotating adjustment screw. If the speed increases to the ejection speed, the ejection counterweight is flung out and hits the ejection control lever, which rotates around its axis, thereby closing the ejection valve. The oil pressure acting on the trip valve is discharged through the gap in the main valve seat of the trip device, thereby allowing the automatic stop oil surrounding the valve seat to be released. The automatic stop prevents oil from flowing directly to the trip piston of the main stop valve. If this oil pressure disappears, it is the operating lubricating oil being discharged from the main stop valve. The spring force activated the stopper, closing the stop valve; as a result, both the main control valve and the main stop valve were closed. Thus, this turbine trip system is designed as a double-check valve. After the jump-off system is turned off, in order to readjust the speed of the jump-off mechanism, this must be done after the turbine speed drops to the lowest speed set by the governor. Chiller turbine overspeed trip scheme. Test steps for the overspeed trip of the chiller turbine CT-401A/B: 1) Ensure that the utility supply is in place, and verify that all parameters of the 4.0 MPa high-pressure steam are within acceptable limits: pressure of 4.12 MPa, temperature of 343°C, with an external flow rate of 5 tons per hour. 2) The maintenance personnel disconnected the couplings of the CT-401A/B units; after confirming that the shaft could rotate freely, they restored the protective covers. 3) After checking to confirm that there are no issues with the oil circuit, start the auxiliary oil pumps P-404A/B according to the steps; the oil circuit system will then begin to operate. At this point, the main things to check are the oil pressure level and the performance of the auxiliary oil pumps. Check for leaks at the same time. 4) Warm up CT-401A/B step by step until they are in normal operating condition; pay attention to steam drainage during this process, and also keep in mind the need to rotate the turbines. 5) Contact the instrumentation to short-circuit the interlock of the compressor that cannot be reset temporarily, and ensure that the turbine is ready for operation. 6) Start CT-401A/B according to the startup procedures, use the start-up handwheel to increase the turbine speed to 500–1000 rpm, and conduct a thorough inspection of the unit to ensure that all parameters are within the specified ranges: no abnormal noises ； Bearing displacement is less than ±0.6mm ； Shaft vibration 3.5 kg/cm2 (PDI-023) ； ⑤Adjust the turbine oil supply temperature to 36~46℃ ； ⑥Adjust the turbine oil supply pressure to 1.0~1.2 kg/cm2 (PG-056) ； (4) End of operation: ① Close each drain valve of the turbine ； ②Slowly open the middle exhaust valve, adjusting its opening degree so that the float ball of the economizer can function properly. 4. Operational preventive measures. ①Check each attachment for vibration and noise ； ②Check the temperature, pressure, and level of the lubricating oil ； ③Check whether the cooling water temperature is below the specified value ； ④Check the main steam and backpressure steam temperatures of the turbine ； ⑤Check the saltwater temperature and the downward trend in evaporator pressure ； ⑥Check the working condition of the float ball ； ⑦Check the evaporation status. VII. Chiller shutdown procedure 1. Confirm with the process team that it is safe to stop the chiller from operating ； 2. Use the regulator knob to reduce the turbine speed to the regulator’s lowest speed of 8640 rpm ； 3. Automatic start of auxiliary oil pump ； 4. Gradually close the main air isolation valve completely by turning its handle to stop the turbine ； 5. Stop the circulating water of the oil cooler ； 6. Close the turbine exhaust isolation valve, open the front and rear drain valves to drain completely, then close them ； 7. Stop the driving steam to the pressure gland-sealed condenser ； 8. Close the main steam isolation valve of the turbine, open the upstream and downstream drain valves to drain all liquid, then close them ； 9. Open the main air shut-off valve, the discharge valve of the housing, and the discharge valve of the steam chamber; close them after all liquid has been drained ； 10. Set PRV to 0% ； 11. Turn HC-001 off to over 50% ； 12. Maintenance after shutdown: ① The turbine auxiliary oil pump shuts down automatically after 8 hours; it can be started manually as appropriate, and the pump stops once the bearings have cooled down ； ②Turn the machine every 2 hours ； ③Drain the standing water. 13. Propylene emissions: ①Close the circulating water valves of condensers E-401A/B ； ②Contact the control room to schedule propylene discharge ； ③Open the safety valve bypass valve of evaporator E-402A/B to discharge to the flare ； ④Open the safety valve bypass valve of condenser E-401A/B to discharge to the flare ； ⑤After the discharge is complete, close the E-401A/B and E-402A/B safety valve bypass valves ； ⑥Open the nitrogen valve and fill with nitrogen ； ⑦Continue to arrange the torches, repeat 3 times ； ⑧Reset of nitrogen filling valve and safety valve bypass valve ； ⑨The oxygen level tested was within acceptable limits. 14. Brine discharge: ① Stop brine pumps P-401A/B/S ； ②Close the brine valve on the tube side of evaporator E-402A/B ； ③Lead tape from the tube side drain of evaporator E-402A/B to brine tank V-401 ； ④Open the vent valve on the tube side of evaporator E-402A/B ； ⑤Open the shell-side drain valve of evaporator E-402A/B. 15. Pressurizing the shell side of condensers E-401A/B: ① Close the circulating water valves on the tube side of E-401A/B; ② Open the vent valve and drain valve on the tube side to drain water ； ③Remove the cover ； ④When pressurizing the shell side, check for leaks from the tube sheet (install blind flanges before pressurization). 16. Pressurizing the shell side of evaporators E-402A/B: ① Close the brine valves on the tube side of E-402A/B ； ②Open the pipe bank vent valve and drain valve to discharge brine ； ③Remove the cover ； ④When pressurizing the tube sheet, check for leaks from the tube sheet (install blind flanges before pressurization). VIII. Emergency Plan for Chiller Operation Incidents 1. What to do if a power outage causes the chiller turbine CT-401 to stop operating? Handling method: (1) Reduce the speed regulator to the lowest speed ； (2) If the turbine load valve is open, close this valve ； (3) Reset the main air shut-off valve ； (4) Open the low-pressure steam valve on the heaters of tanks C-401A/B to heat the tanks to 65~75℃ ； (5) Open all drain valves of the unit ； (6) Open the drive steam valve for the gland-sealed condenser ； (7) Open all drain valves on the main steam line ； (8) Open all drain valves on the backpressure steam line ； (9) If power supply has not been restored, close the main steam line isolation valve and the backpressure steam isolation valve ； (10) After power is restored, start CT-401A/B by following the startup procedures for CT-401A/B. 2. Low oil pressure in chillers C-401A/B. Cause: (1) Clogged oil filter ； (2) Bearing wear ； (3) The pressure gauge is broken and gives inaccurate readings ； (4) Insufficient lubricating oil ； (5) Due to a large amount of propylene dissolving in the oil ； (6) Oil pump failure. Treatment method: (1) Clean the oil filter (replace components) ； (2) Stop the machine to adjust the bearing clearance ； (3) Check and service the pressure gauge ； (4) Refuel ； (5) Increase oil temperature by supplying oil or reduce the cooling water flow in the oil cooler ； (6) Service the oil pump. 3. Oil leakage from the oil tanks of chillers C-401A/B, with poor oil level control. Phenomenon: The oil level in the tanks is not well controlled, and it drops rapidly after refueling. Reason: (1) The pressure of the sealing gas PG-032 is low, allowing oil to seep into the compressor through the seal and eventually accumulate at the bottom of the evaporator ； (2) Seal failure, leakage ； (3) Severe leakage in the oil pipeline ； (4) The heat exchange tubes of the oil cooler are leaking, allowing oil to enter the circulating water. Treatment method: (1) Adjust valve VL-120 so that the pressure of PG032 is 0.7~1.0 kg/cm2 higher than the pressure PG028 in the fuel tank ； (2) Stop the machine to replace the seal ； (3) Shut down to address oil pipeline leaks ； (4) Switch the oil cooler to the other unit, remove the original one and use the oil cooler head instead, then inspect the tube bundles. 4. Abnormal loss of propylene in evaporators E-402A/B. Phenomenon: After propylene is injected into evaporators E-402A/B, the liquid level drops rapidly, indicating a propylene leak. Reason: (1) Internal leakage in the safety valves at the tops of evaporators E-402A/B and condensers E-401A/B, resulting in propylene loss through the flare line ； (2) The relief valve bypass valves for evaporators E-402A/B and condensers E-401A/B are not properly closed or there is internal leakage in the valves ； (3) Severe leakage from the gasket of the sight glass or flange ； (4) The heat exchange tubes in condensers E-401A/B are leaking, causing propylene to leak into the circulating water. Treatment method: (1) Take preventive measures by closing the shut-off valves in front of the safety valves on the tops of evaporators E-402A/B and condensers E-401A/B, and address the safety valves ； (2) Close the safety valve bypass valve or install a blind flange ； (3) Addressing leaks in sight glasses or flange gaskets ； (4) Shut down for maintenance of condensers E-401A/B. 5. If the circulating water is stopped, how should the chillers C-401A/B be handled? Handling method: (1) If the water supply is interrupted for an extended period, shutdown procedures should be followed ； (2) If recovery is possible in a short period of time, appropriate adjustments can be made to ensure the proper operation of the unit ； (3) Start HC-001 to cause the propylene in condensers E-401A/B to reflux, thereby reducing the pressure within those condensers ； (4) Closely monitor the bearing temperature rise; if it exceeds the limit value, initiate an emergency shutdown ； (5) Cool the surface of the oil cooler using other water (such as fresh water). 6. The liquid level in saltwater tank V-401 is dropping abnormally. Phenomenon: The liquid level in saltwater tank V-401 drops rapidly and cannot be maintained. Reason: (1) The drain valve on the inlet line of the salt water pump P-401 was not closed properly or there was internal leakage in the valve, resulting in loss of fluid through the drain ； (2) Tube leakage in the heat exchanger (brine user), with brine leaking into other fluids ； (3) Leakage in the tubes of evaporator E-402 ； (4) There is a leak in the drain valve of the brine circuit. Treatment method: (1) Check and close the drain valve on the inlet line of the salt water pump P-401; if there is internal leakage, replace the valve ； (2) Inspect each heat exchange user; if a leak is found, isolate it and address the tube bundle ； (3) Stop work to handle the tubes in E-402. (4) Check the brine flow and close the drain valve (tightly). 7. The pressure of condensers E-401A/B is abnormally high. Phenomenon: The condenser pressure is high, approaching the trip value of 1.85 Mpa. Reason: (1) High circulating water temperature ； (2) The heat exchange efficiency is extremely poor ； (3) The chiller load is too high. Solution: (1) Contact the dispatch team to lower the temperature of the circulating water ； (2) After adjustment proves ineffective, shut down the condenser tubes ； (3) Reduce chiller load ； (4) The most effective adjustment method is to turn on HC-001 to allow the propylene gas to flow back, thereby reducing the pressure in the condenser. IX. Common faults of ice machines and their solutions 1. Abnormal increase in condenser pressure Reasons: 1) Gas remains in the condenser and has not been completely removed. 2) The condenser tubes are severely blocked and fouled, resulting in insufficient flow of circulating cooling water. 3) There are impurities in the circulating cooling water, which block the inlet of the circulating water. 4) The flow rate of the circulating cooling water is insufficient. 5) The temperature of the circulating cooling water is too high, exceeding 30°C. 2. The internal ribs of the gasket at the end cap of the condenser were not installed, resulting in short-circuit operation of the circulating water. Treatment method: 1) Discharge from the condenser tube side. 2) Shutdown to clean the condenser tubes of the chiller (high-pressure water cleaning). 3) Stop the machine, open the head to inspect and clean it. 4) Check and adjust the circulating water flow rate. 5) Contact the dispatching team to lower the circulating water temperature. 6) Shut down the machine and open the condenser for inspection. 7) Remove non-condensable gases from the propylene to obtain polypropylene-grade propylene. 3. Low evaporator pressure. Cause: Insufficient amount of refrigerant. The refrigerant is too dirty. The float valve is defective. The evaporator tubes are blocked. The PRV opening is too large. Solution: Fill with refrigerant. Purify refrigerant agents. Open the float valve by hand. Park the vehicle and clean the evaporator tubes. Adjust the opening of the PRV and the opening of the HC-001 valve. 4. Abnormal rise in evaporator pressure: Refrigerant liquid is drawn into the compressor (too much propylene). The opening degree of HC-001 is too fast and too large. The condenser pressure is high. The unit load is too high. Solution: Release an appropriate amount of propylene. Slowly adjust the opening degree of the HC-001 valve. Inspect and service the condenser. Adjust the unit load. 5. Significant drop in compressor oil pressure. Cause: Excessive propylene dissolved in the oil, resulting in a decrease in oil viscosity. The oil filter screen is severely clogged. The oil pump is faulty. The oil reserve is too low. There is a problem with the oil pressure gauge. Solution: Increase the temperature of the condenser oil to reduce the amount of propylene dissolved in it. Clean and replace the oil filter element. Check and address the oil pump failure. Check the supplementary condensate oil. Check the treatment oil pressure gauge. 6. Unstable compressor oil pressure, fluctuating up and down. Cause: There is a problem with the oil pressure gauge. Propylene gas is mixed in the oil pressure guiding pipe. There is a problem with the control valve. Solution: Check the oil pressure gauge for processing. Exclude propylene gas. Inspect and adjust the cleaning control valve components. 7. High compressor bearing temperature; low cooling water flow in the oil cooler. The oil cooler tubes are blocked. The lubricating oil is dirty. The bearing is damaged. The oil circulation volume is insufficient. The temperature of the cooling water in the oil cooler is high. Solution: Adjust and increase the water flow rate in the oil cooler. Inspect and clean the oil cooler. Replace the lubricating oil. Check the bearing wear. Check and adjust the fuel tank level. Contact the dispatch team to lower the circulating water temperature. 8. Severe vibration in the unit. Cause: Poor alignment of the unit. The wear gap of the bearing has increased. The labyrinth seal makes contact with the rotor. Liquid present at the compressor inlet. Low load, surge. Other abnormal conditions. Solution: Shut down the machine and realign it. Shut down the machine and check the bearing wear. Adjust the labyrinth seal and rotor clearance. Check the evaporator liquid level and discharge some propylene. Increase the load. Thoroughly inspect the evaporator, condenser, oil circuit, etc., for any abnormalities. 9. Low turbine speed. Cause: Excessive load on the unit. Steam flow is low. The main steam temperature is low. Main steam pressure is low. The backpressure steam pressure is high. Solution: Adjust the load of the speed-regulating unit. Increasing the main steam flow allows the load to be increased appropriately. Increase the main steam temperature. Increase the main steam pressure. Reduce the backpressure steam pressure. 10. The unit cannot start. Reason: The safety device is not connected. There is an alarm or interlock that has not been reset. Instrument failure. Solution: Check if there are any issues with the safety device. Check for any alarms and ensure that interlocks have not been reset. Check the instrument issues. 11. The compressor auxiliary oil pump cannot refill oil. Reason: The pressure at the pump outlet is too low, below the pressure in the oil tank. There is gas inside the pump. The gear is damaged. The oil flow path is not established. There is too little oil in the oil tank. The inhalation tubing is blocked. Solution: Adjust the outlet pressure of the gear pump. Ensure thorough exhaust. Inspect and repair the gear. Check whether the process is correct. Refilling the oil tank. Inspect and clean the pipeline.
It seems that the materials from the 5th floor haven’t been uploaded yet. Can they all be uploaded?
I have uploaded the operating procedures for acrylic compressors; everyone can take a look
Can air be removed using vacuum pumping when filling with propylene?