【Daily Question 2019】Hydrogen production and hydrogenation section – Questions 4–7
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【Daily Question 2019】Hydrogen production and hydrogenation section – Questions 4–7: Briefly explain why heat oil pumps need to be preheated Holiday easy questions 1) If the pump is not preheated, the cold oil or condensed water inside the pump will mix with the hot oil at temperatures of 200–350°C, resulting in vaporization and causing vacuum formation in the pump ； 2) After hot oil enters the pump body, uneven heating of various parts of the pump leads to uneven expansion, resulting in leaks and cracks ； 3) It can also cause the shaft arch waist phenomenon, leading to vibrations ； 4) The medium transported by hot oil pumps has a high viscosity; it has poor flowability at normal and low temperatures, and may even solidify, which prevents the pump from starting or results in a prolonged startup time, leading to tripping. (Unless otherwise specified, all questions and answers are based on hydrogenation units.) ) Correct: 3 wealth, Incorrect: 1 wealth ； Mass posting of posts – rated based on the lowest score ； Replies that are unrelated to the answer are considered spam and will be deleted immediately. For management purposes, if you need to view content from a few days ago, please go to https://bbs.hcbbs.com/home.php?mod=space&uid=3862647&do=thread&view=me&from=space through the summary post below
If a hot oil pump is started without preheating, the hot oil will quickly enter the cold pump body, causing uneven heating of the pump. The upper part of the pump expands more due to heat while the lower part expands less, which can lead to the shaft bending or cause the seal rings on the pump body and those on the rotor to get stuck； Forcing it to start can cause wear, shaft seizure, and shaft breakage. If high-viscosity oils are not preheated, the oil will condense inside the pump, resulting in no flow after startup, or the electromechanical system may trip due to the high starting torque. Due to insufficient preheating, uneven thermal expansion occurs throughout the pump, leading to leaks at the static seal points. Issues such as leaks at the outlet and inlet flanges, the flange on the pump’s cover, or the balance pipes can lead to serious accidents like fires and explosions.
If a hot oil pump is started without preheating, the hot oil will quickly enter the cold pump body, causing uneven heating of the pump. The upper part of the pump expands more due to heat while the lower part expands less, which can lead to the shaft bending or cause the seal rings on the pump body and those on the rotor to get stuck； Forcing it to start can cause wear, shaft seizure, and shaft breakage. If high-viscosity oils are not preheated, the oil will condense inside the pump, resulting in no flow after startup, or the electromechanical system may trip due to the high starting torque. Due to insufficient preheating, uneven thermal expansion occurs throughout the pump, leading to leaks at the static seal points. Issues such as leaks at the outlet and inlet flanges, the flange on the pump’s cover, or the balance pipes can lead to serious accidents like fires and explosions.
If a hot oil pump is started without preheating, the hot oil will quickly enter the cold pump body, causing uneven heating of the pump. The upper part of the pump expands more due to heat while the lower part expands less, which can lead to the shaft bending or cause the seal rings on the pump body and those on the rotor to get stuck； Forcing it to start can cause wear, shaft seizure, and shaft breakage. If high-viscosity oils are not preheated, the oil will condense inside the pump, resulting in no flow after startup, or the electromechanical system may trip due to the high starting torque. Due to insufficient preheating, uneven thermal expansion occurs throughout the pump, leading to leaks at the static seal points. Issues such as leaks at the outlet and inlet flanges, the flange on the pump’s cover, or the balance pipes can lead to serious accidents like fires and explosions.
If a hot oil pump is started without preheating, the hot oil will quickly enter the cold pump body, causing uneven heating of the pump. The upper part of the pump expands more due to heat while the lower part expands less, which can lead to the shaft bending or cause the seal rings on the pump body and those on the rotor to get stuck； Forcing it to start can cause wear, shaft seizure, and shaft breakage. If high-viscosity oils are not preheated, the oil will condense inside the pump, resulting in no flow after startup, or the electromechanical system may trip due to the high starting torque. Due to insufficient preheating, uneven thermal expansion occurs throughout the pump, leading to leaks at the static seal points. Issues such as leaks at the outlet and inlet flanges, the flange on the pump’s cover, or the balance pipes can lead to serious accidents like fires and explosions.
1) If the pump is not preheated, the cold oil or condensate inside the pump will mix with the hot oil at temperatures of 200–350°C, resulting in vaporization and causing the pump to experience vacuum； 2) After hot oil enters the pump body, uneven heating of various parts of the pump leads to uneven expansion, resulting in leaks and cracks ； 3) It can also cause the shaft arch waist phenomenon, leading to vibrations ； 4) The medium transported by hot oil pumps has a high viscosity; it has poor flowability at normal and low temperatures, and may even solidify, which prevents the pump from starting or results in a prolonged startup time, leading to tripping.
1) If the pump is not preheated, the cold oil or condensate inside the pump will mix with the hot oil at temperatures of 200–350°C, resulting in vaporization and causing the pump to experience vacuum； 2) After hot oil enters the pump body, uneven heating of various parts of the pump leads to uneven expansion, resulting in leaks and cracks ； 3) It can also cause the shaft arch waist phenomenon, leading to vibrations ； 4) The medium transported by hot oil pumps has a high viscosity; it has poor flowability at normal and low temperatures, and may even solidify, which prevents the pump from starting or results in a prolonged startup time, leading to tripping.
1) If the pump is not preheated, the cold oil or condensate inside the pump will mix with the hot oil at temperatures of 200–350°C, resulting in vaporization and causing the pump to experience vacuum； 2) After hot oil enters the pump body, uneven heating of various parts of the pump leads to uneven expansion, resulting in leaks and cracks ； 3) It can also cause the shaft arch waist phenomenon, leading to vibrations ； 4) The medium transported by hot oil pumps has a high viscosity; it has poor flowability at normal and low temperatures, and may even solidify, which prevents the pump from starting or results in a prolonged startup time, leading to tripping.
1) High temperature: Hot oil pumps generally operate at temperatures ranging from 200 to 350°C. If the pump is not preheated and remains cold, the entry of hot oil into it causes a large temperature difference, which puts stress on the pump and can lead to leaks, cracks, damage to components. Additionally, differences in thermal expansion coefficients may cause two parts to stick together. 2) High viscosity: The fluids transported by hot oil pumps have high viscosity; they solidify at normal and low temperatures, and may even block the pump’s pipelines, resulting in an inability to start the pump properly, low flow rates and head pressure, as well as vibrations and noise in the pump.
Answer: 1. If the pump is not preheated, the cold oil or condensed water inside the pump will mix with the hot oil at temperatures of 200–350°C, resulting in vaporization and causing vacuum formation in the pump. 2. When hot oil enters the cold pump body, uneven heating of various parts of the pump leads to uneven expansion, resulting in leaks and cracks. It can also cause the shaft arch waist phenomenon, leading to vibrations. 3. The medium transported by hot oil pumps has a high viscosity; it has poor flowability at normal and low temperatures, and may even solidify, which prevents the pump from starting or results in a prolonged start-up time, leading to tripping.