Liquefied natural gas

In LNG refrigeration units, an excessively low return temperature of the LNG refrigerant in a MRC (mixed refrigeration cycle) system can lead to reduced efficiency or instability in the system. Methods to address this issue include: 1. Adjusting the amount of refrigerant: increasing or decreasing the flow rate of some of the refrigerant in order to appropriately raise the return temperature. 2. Check the performance of the heat exchangers: Ensure that all relevant heat exchangers are functioning properly, with no blockages or issues related to reduced performance. 3. Check the circulation pump in the refrigeration system: Verify that the circulation pump is operating properly, with no signs of inefficiency or malfunction. 4. System parameter adjustment: Readjust the operational parameters of the system, including pressure and flow rate, to achieve an optimal operating condition. It is recommended that inspections and adjustments be carried out by technically skilled personnel to ensure the secure and efficient operation of the system. .

Explain in more detail; I didn’t understand. What is the temperature at the inlet – 40 degrees – and what is it at the outlet – 8 degrees?

Do you mean that the outlet temperature of the MRC compressor is 40 degrees, and after passing through the cooling box, the temperature of the fluid returning to the compressor inlet is 8 degrees?

To address the issue of low return temperature of the LNG coolant in MRC systems, actions can be taken from the following aspects: Check and adjust the temperature setting – First, verify whether the set temperature of the industrial chiller is too low, which causes the unit to operate frequently in order to reach that low temperature. If it is caused by an excessively low set temperature, the set temperature should be increased appropriately to prevent the water temperature from dropping too low. Adjust the alarm threshold: Check whether the alarm settings of the industrial chiller are set too sensitively. If the alarm threshold is set too low, alarms may be triggered by minor temperature fluctuations. In this case, the alarm setting can be adjusted to a more reasonable range. Inspect and maintain the refrigeration system: Check the temperature sensor: The temperature sensor in industrial chillers is a key component for monitoring water temperature. If the temperature sensor fails or gets damaged, it may cause false alarms indicating that the water temperature is too low. Therefore, it is necessary to check whether the temperature sensor is working properly, and replace or repair it if needed. Inspect the condenser and evaporator: Check whether the condenser of the industrial chiller is clean, free from dirt or blockages, and whether there is frost or impurities in the evaporator, as these factors can affect the water temperature. Necessary cleaning and maintenance should be carried out. Check the refrigerant: The amount of refrigerant filled has a direct impact on the cooling efficiency. If there is too little or too much refrigerant, it can cause abnormal water temperatures in industrial chillers. It is necessary to check whether the amount of refrigerant filled is sufficient; if needed, it should be added or removed. Check and adjust the operating environment: Check the ambient temperature – when not in use for an extended period of time, the water temperature inside industrial chillers may gradually approach the ambient temperature. If the unit is started suddenly at this time with a set temperature that is too low, it may cause the water temperature to drop rapidly and trigger an alarm. For units that have not been in operation for a long time, they should be properly preheated before startup, with the set temperature being increased gradually. Check the cooling water flow: Verify whether the flow rate of the cooling water is normal. If the flow rate is too low, it may cause the water temperature to drop too much. At this point, the flow rate of the cooling water should be adjusted to an appropriate range. Through the above measures, the problem of low reflux temperature of the MRC-based LNG refrigerant can be effectively resolved, ensuring the normal operation and safety performance of industrial chillers.

It’s probably because the amount of refrigerant circulating is too high, causing over-cooling; reduce the load appropriately or increase the amount of natural gas used

Top up the coolant; the temperature of the returning coolant should be around -10