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| Ported from excel file to visual basic for specific calculations of GPHR (Gross Plant Heat Rate), THR (Turbine Heat Rate), STHR (Steam Turbine Heat Rate), NPHR (Nett Plant Heat Rate), Coal Consumption and Thermal Efficiency. Input parameters derived from the heat balance and cycle analysis. |
A black hole is a region of spacetime from which gravity prevents anything, including light, from escaping. The theory of general relativity predicts that a sufficiently compact mass will deform spacetime to form a black hole. Around a black hole there is a mathematically defined surface called an event horizon that marks the point of no return. The hole is called "black" because it absorbs all the light that hits the horizon, reflecting nothing, just like a perfect black body in thermodynamics. Quantum field theory in curved spacetime predicts that event horizons emit radiation like a black body with a finite temperature. This temperature is inversely proportional to the mass of the black hole, making it difficult to observe this radiation for black holes of stellar mass or greater.
Objects whose gravity fields are too strong for light to escape were first considered in the 18th century by John Michell and Pierre-Simon Laplace. The first modern solution of general relativity that would characterize a black hole was found by Karl Schwarzschild in 1916, although its interpretation as a region of space from which nothing can escape was first published by David Finkelstein in 1958. Long considered a mathematical curiosity, it was during the 1960s that theoretical work showed black holes were a generic prediction of general relativity. The discovery of neutron stars sparked interest in gravitationally collapsed compact objects as a possible astrophysical reality.
Black holes of stellar mass are expected to form when very massive stars collapse at the end of their life cycle. After a black hole has formed it can continue to grow by absorbing mass from its surroundings. By absorbing other stars and merging with other black holes, supermassive black holes of millions of solar masses may form. There is general consensus that supermassive black holes exist in the centers of most galaxies.
Despite its invisible interior, the presence of a black hole can be inferred through its interaction with other matter and with electromagnetic radiation such as light. Matter falling onto a black hole can form an accretion disk heated by friction, forming some of the brightest objects in the universe. If there are other stars orbiting a black hole, their orbit can be used to determine its mass and location. These data can be used to exclude possible alternatives (such as neutron stars). In this way, astronomers have identified numerous stellar black hole candidates in binary systems, and established that the core of our Milky Way galaxy contains a supermassive black hole of about 4.3 million solar masses.
Design for today, hope that next calculation will bring the proper value for pressure and temperature for each HP heater and turbine inlet :)
Steam drum is the reservoir at the top of the water tube boiler. The water tubes which carry water are connected to the Steam drum. The steam drum serves to extract the steam from the water and send it for superheating. The difference in density causes the steam to rise.
The pressure in the steam drum regulates the steam generation within the boiler. As the steam is extracted, further steam is generated.
The water is sent back to the water drum for further heating.
The Burner of the Boiler is the source of heat in boilers which are powered by natural fuel such as gas or oil. It is the place where the fuel is burnt to produce energy.
The burners in Boilers should combust the fuel with very low emissions. They are sometimes provided with an air source such as a fan to ensure proper combustion with little residue.
Dual Fuel burners can burn both oil and gas. Common fuels are Furnace Oil, Light Oil, Natural Gas and Liquefied Petroleum Gas.
Boiler Burners can range in capacity from 200 kW to 15000 kW
Modern Burners in Boilers have sophisticated electronic controls which algorithms for precise air-fuel mixtures for optimum efficiency.
The steam that is generated from the boiler is wet steam. This steam has water droplets suspended in it. The water in steam can damage the components of a boiler system by way of corrosion. It has lower energy carrying capacity.
Steam Separators are devices used to separate the suspended water from the steam. There are many different methods to achieve this. One method is the use of baffles which are placed in the path of the steam. The baffles collect the water from the steam.
Another method is by using the centrifugal principle. The steam is passed through a chamber where there is a rotary device which spins the steam. Due to the centrifugal principle, water which has a higher mass is separated from the steam and collected.
Another method is by passing the steam through a wire mesh known as a demister. The water particles tend to collect in the mesh while the steam alone passes.
Steam separators usually use more than one method to separate the water droplets from the steam.
Steam Washing in boilers refers to the "washing" of the steam with fresh water or steam with condensate. The objective of steam water is to remove the impurities in steam such as silica. Silica in steam is mostly in the vapor state. Silica can deposit in the blades of turbines and affect the efficiency and the operation.
When water which is at a colder temperature than steam is sprayed on the steam, the silica condenses and gets carried away by the water.
The washing is usually carried in many stages for better efficiency.
The Economizer in a boiler is used to preheat the water which is fed into the boiler by using the exhaust gases of the boiler. In this way, it is able to "economise" or save energy.
The heat of the exhaust gases will be in the range of 380 to 550 degrees Celcius. By utilizing this heat energy, the economizer increases the overall efficiency of the boiler.
The Economizer is in the form of vertical tubes in which the water flows. The gases on the way to the exhaust stack transfer their heat to the economizer. The temperature of the inlet water to the economizer should not be too low as that can result in fouling and corrosion.
The outlet temperature of the economizer is also below the boiling point of the water.
The impedance of a transformer is defined as the percentage of the drop in voltage to the at full load to the rated voltage of the transformer. This drop in voltage is due to the winding resistance and leakage reactance.
Alternatively, the percentage of a transformer can be described as the percentage of the nominal voltage in the primary that is required to circulate the rated current in the secondary.
The impedance of a transformer can be measured by means of a short-circuit test.
The secondary of the transformer whose percentage impedance is to be measured is shorted. The voltage on the primary is gradually increased from zero till the secondary current reaches the transformer's rated value.
The percentage impedance of the transformer is calculated as
Z%= (Impedance Voltage/Rated Voltage)*100
Thus a transformer with a primary rating of 110V which requires a voltage of 10V to circulate the rated current in the short-circuited secondary would have an impedance of 9%.
The percentage impedance of a transformer a crucial parameter when operating transformers in parallel. It also determines the fault level of a system during faults.
