Prize-winning Quiz on Coal Chemical Engineering Knowledge 8
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1 In chemical production, operation records must be filled out carefully, with the error rate to be kept below ( ). A 1% B 2% C 5‰ D 1.5‰ 2 An important indicator for measuring the biodegradability of industrial wastewater is ( ). A COD B BOD C TOD D BOD/COD 3 When working at heights in the chemical plant production area (vertical height above the ground), a safety belt must be worn. A 1.5m B 2.0m C 4.0m D 3.0m The suction height of a pump has a limit, and it is related to the local atmospheric pressure as well as the ( ) of the liquid. A. Mass B. Density C. Volume D. Flow rate. 5 What are the reasons for insufficient flow rate in a centrifugal pump? Answer key: 1. d 2. d 3. d 4. b 5. Answer: ① The suction pipe or the inlet of the pump is blocked, resulting in excessive resistance in the suction pipe. ②The impeller inlet ring is worn, resulting in an excessive gap. ③The pump is rotating in the wrong direction or the impeller is installed backwards. ④The outlet valve is not open or its opening degree is too low. This post was last edited by wbp on 2009-4-8 21:56.]
1、A 2、B 3、B 4、B 5、Cavitation or gas entrapment, blocked or leaking inlet pipeline, worn impeller, worn mouth ring or excessive clearance, gas present inside the pump and in the suction pipe
1 In chemical production, operation records must be filled out carefully, and the error rate should be kept below (D). A 1% B 2% C 5‰ D 1.5‰ 2 An important indicator for measuring the biodegradability of industrial wastewater is (D). A COD B BOD C TOD D BOD/COD 3 When working at heights in the chemical plant production area (vertical height above the ground), (D) it is necessary to wear a safety belt. A 1.5m B 2.0m C 4.0m D 3.0m The suction height of a pump has a limit, and it is related to the local atmospheric pressure as well as the (B) of the liquid. A. Mass B. Density C. Volume D. Flow rate. 5 What are the reasons for insufficient flow rate in a centrifugal pump? (1) The system’s static head increases. (2) The resistance loss increases. (3) Excessive wear of the casing and impeller wear rings. . (4) Leakage in other areas. (5) Clogging, wear, and corrosion of the pump impeller.
1 In chemical production, operation records must be filled out carefully, with the error rate to be kept below (A). A 1% B 2% C 5‰ D 1.5‰ 2 An important indicator for measuring the biodegradability of industrial wastewater is (D). A COD B BOD C TOD D BOD/COD 3 When working at heights in the chemical plant production area (vertical height above the ground), (B) it is necessary to wear a safety belt. A 1.5m B 2.0m C 4.0m D 3.0m The suction height of a pump has a limit, and it is related to the local atmospheric pressure as well as the (B) of the liquid. A. Mass B. Density C. Volume D. Flow rate. 5 What are the reasons for insufficient flow rate in a centrifugal pump? 1. There is a problem with the pump’s design or manufacturing, resulting in insufficient flow rate from the pump itself ； 2. The pump head is lower than the head required by the system ； 3. Clogged outlet pipeline ； 4. Cavitation (vacuuming) ； 5. When the inlet pipeline is under negative pressure, air enters due to poor sealing of the pipeline.
1. In chemical production, operation records must be filled out carefully, with the error rate to be kept below (A). A 1% B 2% C 5‰ D 1.5‰ 2. The important indicator for measuring the biodegradability of industrial wastewater is (D). A COD B BOD C TOD D BOD/COD 3. When working at heights in the chemical plant’s production area (vertical height above the ground), it is necessary to wear a safety belt (B). A 1.5m B 2.0m C 4.0m D 3.0m 4. The suction height of a pump has a limit, and it is related to the local atmospheric pressure and the (B) of the liquid. A. Mass B. Density C. Volume D. Flow rate 5. Reasons for insufficient flow rate in a centrifugal pump: the pump’s head is lower than the head required by the system, there are issues with the pump’s design or manufacturing, the pump itself has a low flow rate, the outlet pipeline is blocked, cavitation occurs, the inlet pipeline is under negative pressure, or air gets in due to poor sealing of the pipelines
1 In chemical production, operation records must be filled out carefully, and the error rate should be kept below (D). D 1.5‰ 2 An important indicator for measuring the biodegradability of industrial wastewater is (D). D BOD/COD 3: When working at heights in the chemical plant production area (vertical height above the ground), (D) a safety belt must be worn. The suction height of the D 3.0m 4 pump has a limit, and it is related to the local atmospheric pressure as well as the (B) of the liquid. B. What are the reasons for insufficient flow in a density 5 centrifugal pump? Problems with the pump’s design or manufacturing, blockage in the pump’s outlet pipeline, poor sealing of the pipelines, etc
1、A 2、B 3、B 4、B 5、Cavitation or gas entrapment, blocked or leaking inlet pipeline, worn impeller, worn mouth ring or excessive clearance, gas present inside the pump and in the suction pipe
1A2D3B4B5: Pump cavitation or pipeline blockage.
1、A 2、D 3、B 4、B 5、What are the reasons for insufficient flow in a centrifugal pump? Cavitation or gas entrapment, blockage or leakage in the inlet pipeline, wear of the impeller, wear of the mouth ring or excessive clearance, presence of gas inside the pump and in the suction pipe
1、A 2、D 3、B 4、B 5、cavitation or gas entrapment, blockage or leakage in the inlet pipeline, worn impeller, worn mouth ring or excessive clearance, presence of gas inside the pump and in the suction pipe
1 In chemical production, operation records must be filled out carefully, and the error rate should be kept below (D). A 1% B 2% C 5‰ D 1.5‰ 2 An important indicator for measuring the biodegradability of industrial wastewater is (D). A COD B BOD C TOD D BOD/COD 3 When working at heights in the chemical plant production area (vertical height above the ground), (D) it is necessary to wear a safety belt. A 1.5m B 2.0m C 4.0m D 3.0m The suction height of a pump has a limit, and it is related to the local atmospheric pressure as well as the (B) of the liquid. A. Mass B. Density C. Volume D. Flow rate. 5 What are the reasons for insufficient flow rate in a centrifugal pump? The main issues include pump cavitation, poor sealing, air leakage in the pipelines, and insufficient inlet pressure
Consultation with LZ: 1. Regarding Question 1 on the error rate in chemical production operation records, Sinopec adopts a standard of 0.5%, while the former Ministry of Chemical Industry used a standard of 1%. It’s unclear where LZ’s answer of 1.5% comes from 2. Regarding question 3, which deals with the height at which safety belts must be worn when working at heights in chemical production areas, the \"AQ3025-2008 Safety Regulations for Work at Heights in Chemical Production Units\" defines this height as 2 meters or more; LZ’s answer is 3 meters. It’s not clear where this figure comes from The remaining answers are unambiguous. Maybe I remembered it wrong; I just want to clarify, with no other intention, and would like to discuss this with the original poster.