【Q&A Question 110】April 20, 2017
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【Q&A Question 110】April 20, 2017: What problems can occur when a turbine operates under overload conditions? The reference answer can be seen after responding; points will be awarded for identifying the key points. (Unless otherwise specified, all questions and answers are based on hydrogenation units.) ) Overloading of a turbine generally leads to the following problems: 1. An increase in the amount of steam entering the turbine results in increased bending stresses on the blades, as well as increased stresses and deflections on the stationary blades of the diaphragm; 2. The increased steam flow also leads to an increase in axial thrust, which raises the temperature of the thrust bearings, and in severe cases can cause the thrust bearing components to burn out; 3. It alters the static characteristics of the turbine, particularly its behavior under load shedding conditions. Scoring criteria: 2 Wealth points for incorrect attempts; 3–8 points for *incomplete* answers. 10 Wealth points for correct answers, provided along with a detailed explanation; 15–20 Wealth points for correct answers with additional *insufficient* details. Please score according to these criteria. 2017 Q&A Summary Thread (updates starting now) http://bbs.hcbbs.com/thread-1657793-1-1.html 2017 Daily Question Summary Thread (updates starting now) http://bbs.hcbbs.com/thread-1657794-1-1.html 2016 Q&A Summary Thread (updates completed) http://bbs.hcbbs.com/thread-1597792-1-1.html Petrochemical Sector – “Creative Ideas for Energy Saving” Campaign (Sponsors sought; highest returns ever) http://bbs.hcbbs.com/thread-1666758-1-1.html Sponsors are being sought for this campaign; those interested can contact the event organizer. Petrochemical deep processing edition – the event to share pictures of chemical equipment has started! Huge amounts of wealth, as well as HChuan coins, are waiting for you to claim them: http://bbs.hcbbs.com/thread-1760733-1-1.html. Notice regarding the collection of chemical engineering technical materials in the “Petroleum and Chemicals Section”: http://bbs.hcbbs.com/thread-1614796-1-1.html (Source: HChuan Chemical Forum)
The motor current increases, the internal components wear out severely, there is excessive noise, and liquid is present
There is significant vibration, the operating conditions are unstable; the turbine valves are at their maximum opening position and cannot be adjusted any further, and the reactor is prone to overheating
Overloading a steam turbine can cause harm: (1) As the amount of steam supplied increases, the bending stress on the blades rises, and at the same time, the deflection caused by the stress on the diaphragms and stationary blades also increases； (2) As the steam inlet volume increases, the axial thrust rises, which leads to an increase in the temperature of the babbitt in the thrust bearings; in severe cases, this can result in the destruction of those bearing components ； (3) When the opening degree of the speed control valve approaches its limit, the hydraulic actuator also reaches near its maximum travel, which deteriorates the performance of the speed control system. Both the rate of speed variation and the lag rate increase, leading to a decline in operational stability.
After the turbine is overloaded, the following problems generally occur: 1. Due to the increased steam inflow, the bending stress on the blades increases； At the same time, the stress on the shrouds and stationary blades, as well as the deflection they experience, also increase ； 2. As the steam inflow increases, the axial thrust rises, which leads to an increase in the temperature of the tungsten carbide bearings; in severe cases, this can result in the destruction of these bearings ； 3. When the opening degree of the speed control valve reaches a position close to its limit, the hydraulic actuator also reaches near its maximum stroke, which deteriorates the performance of the speed control system. Both the rate of speed variation and the lag rate increase, resulting in poorer stability of operation.
(1) As the steam inlet volume increases, the bending stress on the blades increases; simultaneously, the deflection caused by the stresses acting on the diaphragms and stationary blades also increases； (2) As the steam inlet volume increases, the axial thrust rises, which leads to an increase in the temperature of the babbitt in the thrust bearings; in severe cases, this can result in the destruction of those bearing components ； (3) When the opening degree of the speed control valve approaches its limit, the hydraulic actuator also reaches near its maximum travel, which deteriorates the performance of the speed control system. Both the rate of speed variation and the lag rate increase, leading to a decline in operational stability.
⑴ Due to the increased steam inflow, the bending stress on the blades increases. At the same time, the stresses and displacements experienced by the partitions and stationary blades also increase ； ⑵ Due to the increased steam inflow, the axial thrust rises, which raises the temperature of the thrust bearing bushes; in severe cases, this can lead to the destruction of the thrust bearing bushes. Therefore, the temperature changes of Wujin should be closely monitored during operation ； ⑶ Change the static characteristics of the turbine, especially its load rejection characteristics ； ⑷ The condenser vacuum deteriorates.
1. As the steam inlet volume increases, the bending stress on the blades rises, and at the same time, the stress and deflection experienced by the stationary blades of the diaphragm also increase. 2. An increase in the steam inlet volume leads to an increase in axial thrust, which raises the temperature of the thrust bearings; in severe cases, this can result in the destruction of these bearings. 3. It alters the static characteristics of the turbine, particularly its behavior under load rejection conditions.
(1) As the steam inlet volume increases, the bending stress on the blades increases; simultaneously, the deflection caused by the stresses acting on the diaphragms and stationary blades also increases； (2) As the steam inlet volume increases, the axial thrust rises, which leads to an increase in the temperature of the babbitt in the thrust bearings; in severe cases, this can result in the destruction of those bearing components ； (3) When the opening degree of the speed control valve approaches its limit, the hydraulic actuator also reaches near its maximum travel, which deteriorates the performance of the speed control system. Both the rate of speed variation and the lag rate increase, leading to a decline in operational stability.