★Specialized Examination for Chemical Engineering ★ — One question per day (2016-1-21) — Points are awarded for participation
Thread Content
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 (2016-1-20): 1. In pipeline design, the pipe schedule number Sch is often used to indicate the wall thickness of the steel pipe. Below are the temperature-permissible pressure data for pipes made of austenitic stainless steel: Temperature, °C: ≤20, 100, 150, 200, 250, 300, 350, 400; Permissible pressure, Mpa: 137, 137, 137, 130, 122, 114, 111, 107. If pipes made from this material are to be used with a design temperature of 180°C and a design pressure of 1.2 Mpa, which pipe size should be selected? A. Sch40s B. Sch20s C. Sch10s D. Sch5s Answer: C
If a pipe made of this material is to be used, with a design temperature of 180°C and a design pressure of 1.2 Mpa, which pipe schedule should be selected for it? Answer: B. Sch20s
B. Sch20s~~~~~~~~~~~~~~~~
C. Sch10s .
Using the C-insertion method, the allowable stress at 180°C is 132.8 MPa. 1.2/132.8*10^3 = 9.0316; rounded to the nearest value, it is Sch10s
The answer is C: Sch.10s. Sch = design pressure/t * 1000 = 1.2/1300 * 1000 = 9.23; after rounding, this value becomes 10. For stainless steel pipes, the value used is 10s