ESET 223 Lecture 1 Power Plant Basics PDF

ESET-223 Power Engineering & HVAC School of Engineering Technology & Applied Science (SETAS) Lecture 1 Power Plant Basics ESET 223, Winter 2022 Week# 1&2 - Power Plants 1  Power plant basics  Steam turbine Power plant  Gas turbine Power Plant  Combined Cycle Power Plant  Nuclear...

ESET-223 Power Engineering & HVAC School of Engineering Technology & Applied Science (SETAS) Lecture 1 Power Plant Basics ESET 223, Winter 2022 Week# 1&2 - Power Plants 1  Power plant basics  Steam turbine Power plant  Gas turbine Power Plant  Combined Cycle Power Plant  Nuclear power plant  Hydro Electric Power plant ESET 223, Winter 2022 Week# 1&2 - Power Plants 2 ❑ A power plant is assembly of systems or subsystems to generate electricity. The power plant itself must be useful economically and environmental friendly to the society. ❑ A power station (also referred to as a generating station, power plant, powerhouse or generating plant) is an industrial facility for the generation of electric power. ❑ At the center of nearly all power stations is a generator, a rotating machine that converts mechanical power into electrical power by creating relative motion between a magnetic field and a conductor. ❑ The energy source harnessed to turn the generator varies widely. It depends chiefly on which fuels are easily available, cheap enough and on the types of technology that the power company has access to. ❑ Most power stations in the world burn fossil fuels such as coal, oil, and natural gas to generate electricity, and some use nuclear power. ❑ There is an increasing use of cleaner renewable sources such as solar, wind, wave and hydroelectric. Generally power stations produce AC power. ESET 223, Winter 2022 Week# 1&2 - Power Plants 3 ESET 223, Winter 2023 Week# 1&2 - Power Plants 4 A power plant may be defined as a machine or assembly of equipment that generates and delivers a flow of mechanical then electrical energy. The main equipment for the generation of electric power is generator. ❑ When coupling it to a prime mover runs the generator, the electricity is generated. ❑ The type of prime mover determines the type of power plants. The major conventional power plants are: THERMAL POWER PLANT ❑ 1. Steam power plant (Rankine Cycle) 2. Diesel power plant 3. Gas turbine power plant (Brayton Cycle) 4. Combined Cycle Power Plant (Brayton Cycle – Rankine Cycle) 5. Nuclear power plant (Rankine Cycle) 6. Hydro electric power plant (is renewable but conventional) ESET 223, Winter 2022 Week# 1&2 - Power Plants 5 ❑ Power is the rate of doing work, which equals energy per unit of time. ❑ Energy is thus required to produce power. We need energy to run power plants to generate electricity. We need power to run our appliances and heat our homes. Without energy we would not have electricity. ❑ The units of power are watts (W, kW), joules per second (J/s), and horsepower (HP), where ; ▪ 1 Watt = 1 joule per second ▪ 1 Kilowatt = 1,000 Watts ▪ 1 Megawatt = 1,000 kilowatts ▪ 1 Btu/s = 1055 Watts ❑ The units of energy are Joule, Btu or Watt-Hour ❑ Power plants are rated in MW, energy in kWattHour (kWh) ESET 223, Winter 2022 Week# 1&2 - Power Plants 6 ESET 223, Winter 2022 Week# 1&2 - Power Plants 7 https://www.youtube.com/watch?v=IdPTuwKEfmA ESET 223, Winter 2022 Week# 1&2 - Power Plants 8 Power Plants ESET 223, Winter 2022 9 ▪ 1-2 or 1 '-2 ': adiabatic reversible expansion through the turbine. The exhaust vapor at 2 or 2' is usually in the twophase region. ▪ 2-3 or 2' -3: constant temperature and, being a two-phase mixture process, constant pressure heat rejection in the condenser. ▪ 3-4: adiabatic reversible compression by the pump of saturated liquid at the condenser pressure, 3, to subcooled liquid at the steam-generator pressure, 4 . ▪ Line 3-4 is vertical on both the P-V and T-S diagrams because the liquid is essentially incompressible and the pump is adiabatic reversible. ESET 223, Winter 2022 Week# 1&2 - Power Plants 10 ▪ 4-1 or 4-1 ': constant-pressure heat addition in the steam generator. Line 4-B-l-l' is a constant-pressure line on both diagrams. ▪ The portion 4-B represents bringing the subcooled liquid, 4, to saturated liquid at B. The section 4-B in the steam generator is called an economizer. ▪ The portion B-1 represents heating the saturated liquid to saturated vapor at constant pressure and temperature (being a two-phase mixture), and section B-1 in the steam generator is called the boiler or evaporator. ▪ Portion l-1', in the superheat cycle, represents heating the saturated vapor at 1 to 1 '. Section 1-1 ' in the steam generator is called a superheater. ESET 223, Winter 2022 Week# 1&2 - Power Plants 11 Processes: 1-2: Expansion through turbine, Isentropic & Adiabatic 2-3: Condensation in condenser, Isothermal & Isobaric 3-4: Compression by pump, Adiabatic 4-1: Heat addition in Boiler, Isobaric ESET 223, Winter 2022 Week# 1&2 - Power Plants 12 ▪ This is where the heat is added into the system ▪ Heat source may be several types: ▪ Fossil fuel (natural gas, coal, oil, waste) ▪ Nuclear ▪ Biomass ▪ Water is converted to high pressure steam ESET 223, Winter 2022 Week# 1&2 - Power Plants 13 ▪ ▪ ▪ High pressure steam is used to drive the turbine and obtain mechanical power. A generator attached to the turbine generates electricity. This is where work is extracted out of the steam ESET 223, Winter 2022 Week# 1&2 - Power Plants 14 ▪ ▪ ▪ ▪ The steam is condensed back to water. 2 basic types: Necessary as it is very difficult to pump wet vapour back to boiler ▪ Air cooled condenser (heat rejected to air) ▪ Water cooled condenser (heat rejected to water) Liquid can easily be pumped into boiler at relatively low power consumption ESET 223, Winter 2022 Week# 1&2 - Power Plants 15 https://www.youtube.com/watch?v=H1aKEcM2YOo&t=76s ESET 223, Winter 2022 Week# 1&2 - Power Plants 16 ❑ In a generating plant, the potential energy of various types of fuels (fossil, nuclear) is converted into another form of energy (heat energy). This heat is used to generate high pressure superheated steam. ❑ This superheated steam is used to turn fan-like blades inside a turbine. At the exit of the turbine the steam is in low pressure nearly saturated vapor state. ❑ The turbine blades are attached to a pole-like shaft. When the blades inside the turbine begin to turn, the shaft begins to turn. This causes a magnetic field to rotate inside within the generator to flow electrons in the stator coil around it. The resulting flow of electrons is electricity. ❑ Low pressure nearly saturated vapor is passed through the condenser where it is cooled by natural water to saturated water in the same pressure. ❑ This water is then pumped back to the high pressure boiler for the next cycle ESET 223, Winter 2022 Week# 1&2 - Power Plants 17 ❑ The gas turbine obtains its power by utilizing the energy of burnt gases and air, which is at high temperature and pressure by expanding through the several ring of fixed and moving blades. It thus resembles a steam turbine. ❑ To get a high pressure (of the order of 4 to 10 bar) of working fluid, which is essential for expansion, a compressor is required. ❑ The quantity of the working fluid and speed required are more, so, generally, a centrifugal or an axial compressor is employed. ❑ The turbine drives the compressor and so it is coupled to the turbine shaft. To get a higher temperature of the working fluid a combustion chamber is required where combustion of air and fuel takes place giving temperature rise to the working fluid. ESET 223, Winter 2022 Week# 1&2 - Power Plants 18 ESET 223, Winter 2022 Week# 1&2 - Power Plants 19 ❑ Thus, a simple gas turbine cycle consists of (1) a compressor (2) a combustion chamber and (3) a turbine. ESET 223, Winter 2022 Week# 1&2 - Power Plants 20 ❑ Since the compressor is coupled with the turbine shaft, it absorbs some of the power produced by the turbine and hence lowers the work output. Output = Turbine work – work of compressor ❑ The net work is therefore the difference between the turbine work and work required by the compressor to drive it. ❑ Gas turbines have been constructed to work on the following: oil, natural gas, coal gas, producer gas, blast furnace and pulverized coal https://www.youtube.com/watch?v=t7N1kKz5faM https://www.youtube.com/watch?v=eeiu-wcyEbs ESET 223, Winter 2022 Week# 1&2 - Power Plants 21 Agenda Basic Construction o Weather Hood o Filters for Inlet Air o Cooling of Air o Mist Elimination o Manifold o Silencer o Inlet guide Vanes o Bearings o Starting Motor o Compressor o Combustion Chamber o Gas Turbine o Alternator o Chimney / Exhaust /HRSG Weather Hood Silencer Air Pre Filter Manifold Air Air Filter Cooling Com- Com- pressor bustion Mist Eliminator Turbine Exhaust ❑ Air is drawn into the system through inlet hoods that protect the filters from the effects of rain, snow, fog and sun. ❑Air passes through filter cartridges. Dust, sand even submicron particulate are removed, and the air is clean. ❑ Pre-filters have the job of extending the life of the primary filter by capturing larger particulate, such as seeds, leaves, airborne fibers, etc. ❑ They are made of lowcost, relatively low efficiency materials, and are designed to be changed more often than primary filters. ❑ Cooler Air Improves Turbine Performance. Cooling the combustion air ingested by the turbine — even by a few degrees can increase power output substantially. ❑ This is because cooled air is denser and therefore gives the turbine a higher mass-flow rate and pressure ratio, resulting in increased turbine output and efficiency. ❑ As much as 0.5 % per degree Fahrenheit or about 1 % per degree Celsius. There are mainly two types of cooling: ▪ Evaporative cooling and ▪ Chiller Coils cooling. How It Works When the cleaned air is directed from the air inlet filter system into the evaporative cooling media, it flows through wetted media. Where it increases its moisture content by evaporation of water Cooled air then passes through the integral mist eliminator. clean, cooled air is then directed into the turbine inlet How It Works As airflow passes through the chilled coils, the air is cooled through an indirect heat exchange with the cooling fluid. The air then passes through drift eliminator media and into the turbine. The coils are cold and therefore condensation is created. Condensate droplets are directed downward and collected in pans, then directed out of the system. Eliminator blades cause the air to enter the system via a convoluted path. As the air turns, water droplets impinge upon the blades, then coalesce and drain out of the system. Several different blade options are available based on site conditions and required removal efficiencies. Manifold converges the air from different inlets and direct it toward the compressor. It is such designed reduce the friction of air with the walls reducing noise. There are two type of bearing used: A. Journal/sleeve Bearings–It is used to support the Turbine Rotor weight as well as to support any dynamic forces resulting from rotor unbalance and gear to other reactions. B. Thrust Bearing–it is used to maintain the rotor-to-stator axial position. That is it keeps the gap between the stationary blade and the rotating blade. Both of these main bearings and seals are incorporated in Two Housing; One at the inlet frame and the other at exhaust frame. Journal/sleeve Bearings Thrust Bearing: • A thrust bearing is a particular type of rotary bearing. • Like other bearings they permit rotation between parts, but they are designed to support a predominately axial load. Ref: wikipedia It is necessary to vary the amount of air and the angle of attack with changes in speed of the compressor. This is done by varying the angle of the inlet guide vanes. The variable inlet guide vanes (VIGV) are located in front of the first compressor rotor blade. The VIGV is connected through a circular operating ring which controls the uniform opening and closing of all the vanes so that the flow of air remains uniform on the radial area. ESET 223, Winter 2022 Week# 1&2 - Power Plants 35 ❑ A considerable amount of heat energy goes as a waste with the exhaust of the gas turbine. This energy must be utilized. The complete use of the energy available to a system is called the total energy approach. The best approach is the use of combined cycles. There may be various combinations of the combined cycles depending upon the place or country requirements. Even nuclear power plant may be used in the combined cycles. ❑ A gas turbine combined cycle is a combination of an open cycle gas turbine and steam turbine. The exhaust of gas turbine which has high heat content is used as the inlet gas to the steam generator where the combustion of additional fuel may or may not takes place. ❑ This combination increases the efficiency and overall power output of the combined plant. ❑ The greater disadvantages include the complexity of the plant, different fuel requirements and possible loss of flexibility and reliability. ESET 223, Winter 2022 Week# 1&2 - Power Plants 36 ❑ Another advantage in combined cycle are the higher exhaust mass flows, resulting in more steam generation for the steam turbine. ESET 223, Winter 2022 Week# 1&2 - Power Plants 37 https://en.wikipedia.org/wiki/Pressurized_water_reactor Nuclear fuel in the reactor pressure vessel is engaged in a fission chain reaction, which produces heat, heating the water in the primary coolant loop by thermal conduction through the fuel cladding. The hot primary coolant is pumped into a heat exchanger called the steam generator, where it flows through hundreds or thousands of small tubes. Heat is transferred through the walls of these tubes to the lower pressure secondary coolant located on the sheet side of the exchanger where the coolant evaporates to pressurized steam. The transfer of heat is accomplished without mixing the two fluids to prevent the secondary coolant from becoming radioactive. In a nuclear power station, the pressurized steam is fed through a steam turbine which drives an electrical generator connected to the electric grid for transmission. After passing through the turbine the secondary coolant (watersteam mixture) is cooled down and condensed in a condenser. The condenser converts the steam to a liquid so that it can be pumped back into the steam generator. Souce: Wikipedia ESET 223, Winter 2022 Week# 1&2 - Power Plants 38 https://en.wikipedia.org/wiki/Pressurized_water_reactor Components of a Pressurized Water Nuclear reactor: Reactor Core Coolant Moderator Pressurizer Pump Fuel Control Rod ESET 223, Winter 2022 Week# 1&2 - Power Plants 39 (Canada Deuterium Uranium) What is CANDU CANDU ® stands for "CANada Deuterium Uranium". It's a Canadian-designed power reactor of PHWR type (Pressurized Heavy Water Reactor) that uses heavy water (deuterium oxide) for moderator and coolant, and natural uranium for fuel. CANDU-specific features and advantages Use of natural uranium as a fuel • CANDU is the most efficient of all reactors in using uranium: it uses about 15% less uranium than a pressurized water reactor for each megawatt of electricity produced. Siemens Flex plant Combined Cycle https://www.youtube.com/watch?v=eeiu-wcyEbs Steam Turbine principle https://www.youtube.com/watch?v=SPg7hOxFItI&t=20s Rankine Cycle Power Plant https://www.youtube.com/watch?v=IdPTuwKEfmA Boiler Works https://www.youtube.com/watch?v=nL-J5tT1E1k Gas Turbine Operation: https://www.youtube.com/watch?v=HQk4f2s5pTc https://www.youtube.com/watch?v=dXeThXTfFNM ESET 223, Winter 2022 Week# 1&2 - Power Plants 42