★Specialized Examination for Chemical Engineering ★ — One question per day (2015-12-21) — Points are awarded for participation
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This post was last edited by zshiwei2008 on 2015-12-22 07:59. Points system for the daily question: Participation – 1~3 points; Correct answer – 5 points; In-depth analysis – 5~10 points. The answer is provided the next day. Due to limited capabilities, I am unable to provide more in-depth explanations for each question; therefore, on the second day, in addition to offering reference options, I will also remove the restriction on reading replies. I hope that all candidates can learn from one another and improve together! Daily Question (2015-12-21): 1. Which of the following statements regarding the pressure drop in pipeline systems is incorrect? A. During the flow of gas in a pipeline, when the pressure at the end of the pipeline is less than 80% of the pressure at the starting point, the pressure drop should be calculated using the methods applicable to compressible fluids. B. Generally, the resistance coefficient of a globe valve is lower than that of a ball valve. C. To predict the pressure drop in a pipeline, it is necessary to know the physical properties of the fluid flowing within it, especially its viscosity and density. D. Different media require different flow rates, depending on their properties, state, and operational requirements. 2. Among the pressure drop values for every 100 meters of pipe length listed below, which one is inappropriate? A. The pressure drop control value for the heating steam used in the process (P=0.5 Mpa) is 10 Kpa.B. The pressure drop control value for the circulating cooling water pipes is 30 Kpa.
C. The pressure drop control value for the discharge pipes of the pump when the flow rate is 180 m3/h is 45 Kpa.
D. The pressure drop control value for the dedicated gravity-fed discharge pipes for tank cleaning liquid is 5 Kpa.
Reference answer: From the 2010 exam questions; I guess many people have forgotten about them as well. Anyway, I forgot that they were from an actual exam. Question 1: B, Question 2: A
Which of the following statements regarding the pressure drop in pipeline systems is incorrect (B)? A. During the flow of gas in a pipe, when the pressure at the end of the pipe is less than 80% of the pressure at the starting point, the pressure drop should be calculated using the methods applicable to compressible fluids. B. Generally, the resistance coefficient of a globe valve is lower than that of a ball valve. C. To predict the pressure drop in a pipe, it is necessary to know the physical properties of the fluid flowing within it, especially its viscosity and density. D. Different media require different flow velocities, depending on their properties, state, and operational requirements. 2. Among the pressure drop values for each 100 meters of pipe length listed below, which one is inappropriate? (A) A. The pressure drop control value for the heating steam pipeline used in the process (P=0.5 Mpa) is 10 Kpa. B. The pressure drop control value for the circulating cooling water pipeline is 30 Kpa. C. The pressure drop control value for the discharge pipeline of the pump when the flow rate is 180 m3/h is 45 Kpa. D. The pressure drop control value for the dedicated gravity-fed discharge pipeline for the tank cleaning liquid is 5 Kpa
1. B. --------------2、A. ----------------
1. Which of the following statements regarding the pressure drop in piping systems is incorrect? B A. During the flow of gas in a pipeline, when the pressure at the end of the pipeline is less than 80% of the pressure at the starting point, the pressure drop should be calculated using the methods applicable to compressible fluids. B. Generally speaking, the resistance coefficient of a globe valve is lower than that of a ball valve. C. To predict the pressure drop in a pipeline, it is necessary to know the physical properties of the fluid flowing within it, especially its viscosity and density. D. Different media require different flow velocities, depending on their properties, state, and operational requirements. 2. Among the pressure drop values for each 100 meters of pipe length listed below, which one is inappropriate? A. The pressure drop control value for the heating steam pipeline used in the process (P=0.5 Mpa) is 10 Kpa. B. The pressure drop control value for the circulating cooling water pipeline is 30 Kpa. C. The pressure drop control value for the discharge pipeline of the pump when the flow rate is 180 m3/h is 45 Kpa. D. The pressure drop control value for the dedicated gravity-fed discharge pipeline for the tank cleaning solution is 5 Kpa