2. MEL 725: Power Plant Steam Generators P M V Subbarao Professor Mechanical Engineering Department A First Stage Technology for the Development of Civilization!!

3. Steam, The origin of Scientific & Industrial Civilization. Trace the origin of steam. Think about the impact of Steam on Science. Enumerate the impact of steam on Technology. Appreciate the role of steam in industrial world. P M V Subbarao Mechanical Engineering, IIT Delhi

4. The Philosophy of Steam -- Mill There are many features which characterize this progressive economical movement of civilized nations. The best of the best feature which excites attention – What is it? This is the feature which intimately connected with the phenomena of production This is the perpetual. The unlimited growth of man's power over Nature so far as human foresight can extend.

5. Science of Cooking Methods Camp fire Wood Stove Gas Stove Micro Wave P M V Subbarao Mechanical Engineering, IIT Delhi

6. Science of Lighting Wick lamp Gas Lamp Electric Lamp

7. Science of Motive Power : Land Horse Cart Steam Wagon Car P M V Subbarao Mechanical Engineering, IIT Delhi

8. Science of Motive Power : Sea Man power Ship Steam Engine Ship Steamer

9. Science of Motive Power : Air Propeller aircraft Turbojet Aircraft Supersonic aircraft P M V Subbarao Mechanical Engineering, IIT Delhi

10. How Come?

11. Human being is a WEAK Animal Yet dominates the GLOBE !?!?!?! Human being has ability to provide power, set LIMITS to the rate of growth of Civilization. P M V Subbarao Mechanical Engineering, IIT Delhi

12. The Philosophy of Steam -- Mill Our knowledge of the properties and laws of physical objects shows no sign of approaching its ultimate boundaries!!!!! It is advancing more rapidly, and in a greater number of directions at once, than in any previous age or generation. Affording such frequent glimpses of unexplored fields beyond as to justify the belief that our acquaintance with Nature is still almost in its infancy.

13. Origin of Steam : Basis of Scientific & Technological Research Denis Papin, while working at Huygens and of Boyle, started to be interested in the vapor. Several geniuses of science tried before him to try out an unspecified machine which would run on the vapor, but their efforts were useless. It is into 1707 that Denis Papin made his first great realization: the boat with vapor. This superb invention brought much controversy near the boatmen, who destroyed the ship. P M V Subbarao Mechanical Engineering, IIT Delhi

14. The Boiler ……… Boilers are accepted equipment of everyday life. A prime device which connects natural resources and human-made facilities. A fire… A furnace…. A boiler ….. A Steam generator.

15. The Steam Machines were in industrial use since 1712. P M V Subbarao Mechanical Engineering, IIT Delhi Establishment of the first and second laws of thermodynamics by Clausius, Kelvin et al., occurred in 1855!!!

16. This Led to Formulation of Greatest Science …. Thermodynamics

17. A Science of Human Development through Energy Utilities. Thermodynamics P M V Subbarao Mechanical Engineering, IIT Delhi

18. Depth of Knowledge of Thermal Sciences is A Measure of Growth of Technology & Civilization……

19. The Great Albert Einstein`s Opinion A Theory is more impressive –the greater the simplicity of its premises is, –the more different kinds of things it relates, –and the more extended is its area of applicability. Therefore, the deep impression which Classical Thermodynamics made upon me.  It is only physical theory of universal content concerning which I am convinced that, Within the framework of the applicability of its basic concepts, it will never be overthrown. P M V Subbarao Mechanical Engineering, IIT Delhi

20. Analysis of Power Plant Steam Generators Available Resources (Energy, matter etc.,) Engineering Design of Thermal processes, devices and systems. Is Design meeting Human’s NEED? YES (task completed) NO Social Sciences and Humanities Thermodynamics Laws and Information Other Engineering Sciences

21. Technology Vs Power

22. Historical Development of Steam Generators BY P M V Subbarao Professor Mechanical Engineering Department I I T Delhi A Progressive development towards perfection!!!!!!! A Quick Tour from Zero DOF to 4 DOF Technology !!!!!! P M V Subbarao Mechanical Engineering, IIT Delhi

23. Historical Eras of Technology

24. Historical Development in Steam Generators

25. FIRE, FLAME and TORCH Fire is a discovery rather than an invention. Homo erectus probably discovered fire by accident. Fire was most likely given to man as a 'gift from the heavens' when a bolt of lightning struck a tree or a bush, suddenly starting it on fire. The flaming touch and the campfire probably constituted early man's first use of 'artificial' lighting. As early as 400,000 BC, fire was kindled in the caves of Peking man. Prehistoric man, used primitive lamps to illuminate his cave. Various Oils were used as fuels.

27. The Aelopile In 130BC. Hero, a Greek mathematician and scientist is credited with inventing the first practical application of steam power, the aelopile.

28. Branca's Steam Engine In 1629, Giovanni Branca, of the Italian town of Loretto, described, in a work' published at Rome, a number of ingenious mechanical contrivances, among which was a steam-engine in which the steam, issuing from a boiler, impinged on the basis of a horizontal well. This it was proposed to apply to many useful purposes

29. Newcomen Engine In 1712 Thomas Newcomen developed a Steam engine called Atmospheric engine. a b © d e f

30. 1720 Haycock : Shell-type boiler made of copper plates

31. Historical Development of Boilers 1720 Haycock : Shell-type boiler made of copper plates. 1730 James Allen: Internal flue furnace; use of bellow for combustion air 1766 William Blakey: Patent on water in turbe and fire outside. 1803 John Stevens: A pseudo-water-tube design used in a steamboat. 1804 Richard Trevithick” First high pressure boiler with cast iron cylindrical shell. 1822 Jacob Perkins: Once-through boiler using cast iron bars. 1856 Stephen Wilcox: Inclined tube boiler with water-cooled enclosures. 1880 Allan Stirling: Bent tube connecting drums. 1920: Pulverized Coal fired boiler. 1957: Super critical boiler. 1970: Fluidized bed boiler.

32. The Theory of Producing Steam Water and steam are typically used as heat carriers in heating systems. It is well known that water boils and evaporates at 100°C under atmospheric pressure. By higher pressure, water evaporates at higher temperature - e.g. a pressure of 10 bar equals an evaporation temperature of 184°C. During the evaporation process, pressure and temperature are constant, and a substantial amount of heat are use for bringing the water from liquid to vapour phase. When all the water is evaporated, the steam is called dry saturated. In this condition the steam contains a large amount of latent heat. This latent heat in the dry saturated steam can efficiently be utilised to different processes requiring heat. The steam boiler or steam generator is connected to the consumers through the steam and condensate piping. When the steam is provided to the consumers, it condensate. It can then be returned to the feed water tank.

33. Water Tube Boilers: The Steam Generators As industry developed during 19 th century, so the use of boilers for raising steam became widespread. Disastrous explosions sometimes occurred. Boilers of that period consisted of heated pressure vessels of large diameter. These are subject to internal pressure which is tensile stresses in the walls of the enclosure. The value of stress, known as ‘hoop stress’ is given by

34. Steam generator versus steam boiler Opposite the principle of the steam boilers, the water in the steam generators evaporates inside the tube winded up into serial connected tube coils. The feed water is heated up to the evaporation temperature and then evaporated. The intensity of the heat, the feed water flow and the size/length of the tube are adapted, so that the water is exactly fully evaporated at the exit of the tube. This ensures a very small water and steam volume (content of the pressure vessel). Thus there are no buffer in a steam generator, and is it temporary overloaded. The advantages using a steam generator compare to conventional steam boilers: Easy to operate - normally no requirement for boiler authorisation Rapid start-up and establishing full steam pressure Compact and easy to adapt in the existing machinery arrangement Price attractive - especially at low steam rates.

35. The advantages using a steam generator compare to conventional steam boilers: Easy to operate - normally no requirement for boiler authorisation Rapid start-up and establishing full steam pressure Compact and easy to adapt in the existing machinery arrangement Price attractive - especially at low steam rates.

36. The water tube boiler As you can see, the Water Tube Boiler (below) looks very complicated. Thousands of tubes are placed in strategic location to optimize the exchange of energy from the heat to the water in the tubes. These types of boilers are most common because of their ability to deliver large quantities of steam. The large tube like structure at the top of the boiler is called the steam drum. The hundreds of tube start and eventually end up at the steam drum.

37. Steam Theory Within the boiler, fuel and air are force into the furnace by the burner. There, it burns to produce heat. From there, the heat (flue gases) travel throughout the boiler. The water absorbs the heat, and eventually absorb enough to change into a gaseous state - steam. To the left is the basic theoretical design of a modern boiler. Boiler makers have developed various designs to squeeze the most energy out of fuel and to maximized its transfer to the water.

38. Water enters the boiler, preheated, at the top. The hot water naturally circulates through the tubes down to the lower area where it is hot. The water heats up and flows back to the steam drum where the steam collects. Not all the water gets turn to steam, so the process starts again. Water keeps on circulating until it becomes steam. Meanwhile, the control system is taking the temperature of the steam drum, along with numerous other readings, to determine if it should keep the burner burning, or shut it down. As well, sensors control the amount of water entering the boiler, this water is know as feedwater. Feedwater is not your regular drinking water. It is treated with chemicals to neutralize various minerals in the water, which untreated, would cling to the tubes clogging or worst, rusting them. This would make the boiler expensive to operate because it would not be very efficient.

39. On the fire side of the boiler, carbon deposit resulting from improper combustion or impurities in the fuel can accumulate on the outer surface of the water tube. This creates an insulation which quickly decrease the energy transfer from the heat to the water. To remedy this problem the engineer will carry out soot blowing. At a specified time the engineer uses a long tool and insert it into the fire side of the boiler. This device, which looks like a lance, has a tip at the end which "blows" steam. This blowing action of the steam "scrubs" the outside of the water tubes, cleaning the carbon build up. Water tube boilers can have pressures from 7 bar to as high as 250 bar. The steam temperature's can vary between saturated steam, 100 degrees Celsius steam with particle of water, or be as high as 600 - 650 degrees Celsius, know as superheated steam or dry steam The performance of boiler is generally referred to as tons of steam produced in one hour. In water tube boilers that could be as low as 1.5 t/hr to as high as 2500 t/hr.

40. Water Tube Boiler A.Smoke uptake B.Economizer A heat exchanger that transfers heat from Boiler Flue Gases to Boiler Feedwater. C.SteamOutlet Saturated steam from the SteamDrum to the Superheater D.Cyclone A device inside the drum that is used to prevent water and solids from passing over with the steamoutlet. E.Stay tube for superheater

41. F.Superheated steam outlet G.Superheater A bank of tubes, in the exhaust gas duct after the boiler, used to heat the steam above the saturation temperature. H.Superheater Headers Distribution and collecting boxes for the superheater tubes. I.WaterDrum J.Burner K.Waterwall Header Distribution box for waterwall and downcomers. L.Foting M.Waterwall Tubes welded together to form a wall. N.Waterwall Header Distribution box for waterwall and downcomers.

42. O.Back side waterwall P.Boiler hood Q.Waterwall Header Collecting box for waterwall and risers. R.Riser Tubes in which steam is generated due to high convection or radiant heat. The water-steam emulsion rises in these tubes toward the steamdrum. S.Downcomer A tube through which water flows downward. These tubes are normally not heated, and the boiler water flows through them to supply the generating tubes. T.SteamDrum Separates the steam from the water. U.Economizer Header Distribution box for the economizer tubes.

43. water tube steam boiler V2M8 with regenerative air preheater A Vertical Boiler whose major design features are the gastight waterwall furnace and the vertical in-line inverted U-loop superheater. The boiler shown is top-fired with resulting improved gas distribution over the entire superheater furnace. Both the main-bank tubes and superheater elements are in-line for improved tube cleaning. Normally, soot-blowing equipment includes retractable blowers in the superheater and rotary blowers in the main bank and economizer. The combustion air preheater, on the top of the boiler, heats the inlet combustion air to the burners by means of the flue cases and improves the efficiency of the boiler.

44. Water and steam flow diagram Blue: the downcomers lead the water from the steam drum to the water drum and the waterwalls headers. Red and blue: the evaporation tubes and the water walls lead the water and steam emulsion back to the steam drum. Red: the steam passes through the superheater before it leaves the boiler for the consumers

45. One large V2M8 boiler is installed in a ship at a shipyard and one other boiler is still suspended in the crane-hook. When the boilers are placed and secured then the engine room will be built around them.

46. water tube steam boiler V2M9 with regenerative air preheater The most outstanding feature of the V2M9 is the combustion. The boiler is a vertical two-drum dropped- furnace boiler. A burner is located at each of the four corners of the furnace and the burners are aligned to be tangential to a circle in the center of the furnace. This arrangement gives a rotary motion to the combustion gases within the furnace, with improved turbulence and air/fuel mixing. This lengthens the fuel-particle residence time in the furnace and allows combustion to be completed before the gases pass into the convection generating bank and superheaters

47. Water and steam flow diagram Blue: the downcomers lead the water from the steam drum to the water drum and the water walls headers. Red and blue: the evaporation tubes and the waterwalls lead the water and steam emulsion back to the steam drum. Red: the steam passes through the superheater before it leaves the boiler for the consumers.

48. Eckrohr Steam Boilers Eckrohr-Boiler (Corner Tube Boiler) is a boiler for all kinds of fuel. Originally it got its name because it has downcomers in the four corners. It is a natural water circulation single drum boiler and it needs no circulation pump. Downcomers, headers and waterwalls are welded together to a gas-tight tube cage. The Eck-rohr-Boiler is self- supporting and needs no supporting structure. It stands on its own downcomers. Due to the cage structure with downcomers, headers and overhead pipes the Eckrohr-Boiler is earthquake safe (more than 550 boilers installed in Japan, many of them for municipal waste).

49. Eckrohr Boilers water and steam flow diagram 1.Unheated return tubes 2.Header 3.Mixture tubes 4.Riser tubes (evaporator) 5.Overflow tubes 6.Unheated steam drum 7.Unheated downcomers The water-steam mixture flows upwards through the riser tubes (4). In the upper mixture tube (3) steam is already separated from water and a part of the water flows through unheated return tubes (1) to the header (2). The separated steam flows through the overflow tube (5) to the steam space of the drum (6). The remaining mixture runs through mixture tube (3) into the drum. The final separation of water and steam takes place in the drum, the water flows through the downcomers (7) to the headers (2).

50. Composite steam boiler Composite boilers that mixes the diesel engines exhaust gases and the flue gases from the fuel oil burner have existed, and may still exist. Using the diesel engines exhaust gases as combustion air for the fuel oil burner is quite economically although it makes a rather complicated unit.

51. Steam Generator Design Steam generators can be delivered in horizontal execution (with low height), or in vertical execution (occupying limited floor space). They are delivered as insulated with stainless steel cover sheets and complete with burner, armatures, instrumentation, safeties and a control panel. The steam generators heaters are made with coils made of seamless tubes, where the feed water is preheated and evaporated during the flow through these. The heat is transferred to the water/steam mixture as radiant heat in the combustion chamber, where the inner cylindrical tube coil and a flat tube coil forms the chamber wall and the bottom respectively. Consequently refractory concrete is avoided. The combustion gasses are hereafter cooled in the outer convection part, as the gasses pass the space between the two tube coils.

52. The thermal design ensures a modest volume of steam relative to the size of the heater, and allows unlimited thermal expansion due to the high temperatures. Beside the standard execution the steam generators can be delivered in following variations: Electrical heated, including EX-design if required Material in stainless steel Complete skid-mounted with tanks and pretreatment equipment.

53. Classification of Boilers Packaged Boilers : Small in capacity. –Preassembled units. –Shell type or watertube Shell type: Domestic hot water boilers are most common example. –Low Thermal efficiency 50 -- 65%. Water-tube Type: Packaged water-tube boilers are built incapacity up to 25 kg/s –Pressure up to 73 bar and temperature up to 440 C. –furnace operates under positive pressure. –Designed for compactness. –Operated with a very high volumetric heat release rate. Marine or Naval Boilers : Extremely compact. –Built to maximize the power-to-weight and power-to-volume ratio. –High heat release rates: up to 10 MW per cubic meter in Naval vessels and up to 1 Mw per cubic meter in merchant vessels. –Generally oil fired. –Modern ships using diesel engine or gas turbine power use a waste heat recovery boiler or auxiliary pakage boiler.

54. Power Generation Boilers –Pulverised coal combustion. –Fluidized Bed Combustion. Solid Waste Fired Boilers Biomass Fired Boilers Waste Heat Recovery Boilers. Nuclear Steam Generators.

55. Classification of Boilers