Title 22566 POWER PLANT ENGINEERING WINTER 2024 MODEL ANSWER.pdf ✅

MAHARASHTRA STATE BOARD OF TECHNICAL EDUCATION (Autonomous) (ISO/IEC - 27001 - 2013 Certified) __________________________________________________________________________________________________ Page No: 1/17 WINTER – 2024 EXAMINATION Model Answer – Only for the Use of RAC Assessors Subject Name: POWER PLANT ENGG Subject Code: Important Instructions to examiners: 1) The answers should be examined by key words and not as word-to-word as given in the model answer scheme. 2) The model answer and the answer written by candidate may vary but the examiner may try to assess the understanding level of the candidate. 3) The language errors such as grammatical, spelling errors should not be given more Importance (Not applicable for subject English and Communication Skills. 4) While assessing figures, examiner may give credit for principal components indicated in the figure. The figures drawn by candidate and model answer may vary. The examiner may give credit for any equivalent figure drawn. 5) Credits may be given step wise for numerical problems. In some cases, the assumed constant values may vary and there may be some difference in the candidate’s answers and model answer. 6) In case of some questions credit may be given by judgement on part of examiner of relevant answer based on candidate’s understanding. 7) For programming language papers, credit may be given to any other program based on equivalent concept. 8) As per the policy decision of Maharashtra State Government, teaching in English/Marathi and Bilingual (English + Marathi) medium is introduced at first year of AICTE diploma Programme from academic year 2021-2022. Hence if the students write answers in Marathi or bilingual language (English +Marathi), the Examiner shall consider the same and assess the answer based on matching of concepts with model answer. WINTER – 2024 EXAMINATION Model Answer – Only for the Use of RAC Assessors Subject Name: POWER PLANT ENGG Subject Code: Q. No Sub Q. N. Answer Marking Scheme 1 Attempt any FIVE of the following 10M a) List components hydro-electric power plant. 2M Answer: components hydro-electric power plant 1 Dam 2 Reservoir 3 Penstock 4 Surge Tank 5 Gate 6 Turbine 7 Draft Tube 8 Power House 9 Transformer Any four 1/2 marks each 22566 XXXXX 22566 XXXXX
MAHARASHTRA STATE BOARD OF TECHNICAL EDUCATION (Autonomous) (ISO/IEC - 27001 - 2013 Certified) __________________________________________________________________________________________________ Page No: 2/17 b) State classification of high pressure boiler. 2M Answer: 1 LaMont Boiler 2 Benson Boiler 3 Schmidt-Hartmann Boiler 4 Loeffler Boiler 5 Velox Boiler 6 Ramsin Boiler Any four 1/2 marks each c) State any four advantages of Gas Turbine Power Plants. 2M Answer: 1. Low capital cost. 2. Low as less operating staff is required. 3. Control of gas turbine is easier. 4. Requires less space. 5. Fewer vibrations due to perfect balancing. 6. The ignition and lubrication systems are much simpler. 7. Poor quality fuels can be used. 8. Efficiency of gas turbine is not the criteria for its selection. It is used in aviation and Propulsion and generally fit into the overall shape of the structure. 9. It is selected due to its simplicity, lack of cooling water, needs quick installation and quick starting. Any four 1/2 marks each d) Define the need of cogeneration 2M Answer: Need of Co-generation A) Co-generation power plants does maximum utilization of primary fuels B) Co-generation satisfies the need of electricity and process heat simultaneously C) Instead of using two separate units for generation of heat and power uses single cogeneration plant Any Two points (each point 1 marks)

MAHARASHTRA STATE BOARD OF TECHNICAL EDUCATION (Autonomous) (ISO/IEC - 27001 - 2013 Certified) __________________________________________________________________________________________________ Page No: 4/17 2 Attempt any THREE of the following 12 a) State any four applications of diesel power plant 4M Answer: 1. Diesel power plants are suitable for mobile power generation and they are widely used in transportation system such as rail, ships etc. 2. They can be used as pick load plants for some other types of power plants. 3. They can be used as emergency power plants i.e. stand by power plant. 4. They can be used in small scale industries. 5. They can be used for small nursery station. 6. They can be used as small capacity central stations. 1 marks each b) Explain types of control system in steam power plant. 4M Answer: 1. Feed water Control System: The objective of the feed water control is to supply enough water to the boiler to match the evaporation rate. For the subcritical plant, because the separation of steam from water always happens at the drum, maintaining the drum level naturally represents the balance between the feed water supply and steam generation. Controlling the drum water level within a given tolerance is important for the safe operation of the plant: a high level will increase the risk of water being carried over into the steam circle, which may not only lead to a fluctuation of steam temperature, but also cause fouling and damage of the super heaters; conversely, a low level will cause the water wall piping to be damaged from insufficient cooling. Both can result in catastrophic failures. 2. Steam Temperature Control System : Super heater steam temperature (SST) and Reheater steam temperature (RST) are two of the most critical variables to be controlled in a steam power plant. They must be tightly controlled within a small range for the following safety and economy reasons: 1- Excessively high temperature will lead to material damage on the super heater/reheater steam pipes at the inlet of the turbine; 2- Lower temperature will reduce the efficiency of the plant, moreover, it will build up the steam humidity in the rear of the low pressure turbine that would erode the turbine blades; 3- Large temperature variation will increase the thermal stress of the piping material and magnify the variations of the air gap between rotor and stator of the turbine, thus threatening the safety of the plant 2 Marks for explanati on each system