(Daily Question) Coal-to-Oil and Olefins Forum, 2018.1.25
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3.jpg Participation: Prize of 5 Wealth； Correct answer: Reward of 10 wealth points ； Note: This post is valid for 48 hours. Question: (DMTO) What are the methods used in practical operation of olefin separation units to prevent surging? (1) Bypass return to ensure minimum flow rate ； (2) Adjust the surge point by changing the rotational speed. According to the compressor characteristic curve, as the compressor speed decreases, the surge point shifts to the left; in other words, the minimum flow rate of the compressor decreases, thereby preventing surge ； (3) Increase the spray volume to lower the suction temperature and boost the mass flow rate; this method can be applied to refrigeration compressors. Note: The answer will be released automatically in two days!
Answer: There are manual and automatic methods to prevent surge, both of which involve installing a bypass pipe at the fan’s outlet. It should be opened first when starting the fan, and gradually closed once startup is complete. When signs of surge appear, the automatic vent valve opens automatically according to a pre-set procedure, increasing the flow rate at the fan inlet and allowing the operating point to shift from the surge zone to a stable operating region. Thereby gradually increasing the outlet pressure, so as to slowly feed compressed air into the pipeline network. While ensuring that the outlet pressure is greater than the pipeline network pressure, this vent valve gradually closes or remains in an appropriate position. Manual operation of valves must be carried out by workers familiar with the details, following the procedures for automatic valves.
Appropriate anti-surge control strategies can be developed. The anti-surge controller (system) measures parameters such as temperature, pressure, speed, and flow rate at each stage of the compressor; it enables control over the opening condition and degree of the anti-surge control valve. At the same time, it is necessary to check the operating condition of the compressor to ensure its reliable and safe operation.
(DMTO) Methods to prevent surging in the olefin separation unit during actual operation? Answer: (1) Return via bypass to ensure minimum flow rate ； (2) Adjust the surge point by changing the rotational speed. According to the compressor characteristic curve, as the compressor speed decreases, the surge point shifts to the left; in other words, the minimum flow rate of the compressor decreases, thereby preventing surge ； (3) Increase the spray volume to lower the suction temperature and boost the mass flow rate; this method can be applied to refrigeration compressors.
1. It can reduce the compressor speed. 2. Start the counter-flight motion path. 3. Increase incoming traffic.
Answer: There are manual and automatic methods to prevent surge, both of which involve installing a bypass pipe at the fan’s outlet. It should be opened first when starting the fan, and gradually closed once startup is complete. When signs of surge appear, the automatic vent valve opens automatically according to a pre-set procedure, increasing the flow rate at the fan inlet and allowing the operating point to shift from the surge zone to a stable operating region. Thereby gradually increasing the outlet pressure, so as to slowly feed compressed air into the pipeline network. While ensuring that the outlet pressure is greater than the pipeline network pressure, this vent valve gradually closes or remains in an appropriate position. Manual operation of valves must be carried out by workers familiar with the details, following the procedures for automatic valves.
Open the compressor anti-surge control valve to achieve this
There are two methods to prevent surge: manual and automatic, both of which involve installing a bypass pipe at the outlet of the fan. It should be opened first when starting the fan, and gradually closed once startup is complete. When signs of surge appear, the automatic vent valve opens automatically according to a pre-set procedure, increasing the flow rate at the fan inlet and allowing the operating point to shift from the surge zone to a stable operating region. Thereby gradually increasing the outlet pressure, so as to slowly feed compressed air into the pipeline network. While ensuring that the outlet pressure is greater than the pipeline network pressure, this vent valve gradually closes or remains in an appropriate position. Manual operation of valves must be carried out by workers familiar with the details, following the procedures for automatic valves.
Answer: (1) Return via bypass to ensure minimum flow rate； (2) Adjust the surge point by changing the rotational speed. According to the compressor characteristic curve, as the compressor speed decreases, the surge point shifts to the left; in other words, the minimum flow rate of the compressor decreases, thereby preventing surge ； (3) Increase the spray volume to lower the suction temperature and boost the mass flow rate; this method can be applied to refrigeration compressors.