LECTURE NOTES ON POWER PLANT ENGINEERING IV B.Tech I Semester (JNTUH-R13) Ms.G.KARUNYA Assistant Professor MECHANICAL ENGINEERING INSTITUTE OF AERONAUTICAL ENGINEERING DUNDIGAL, HYDERABAD-500043
UNIT-1 STEAM POWER PLANT Introduction: Power Plant Engineering is a science, which deals with the complete study of different types of power plant. Sources are divided into two types 1. Conventional sources (Non-Renewable Sources)-these are consumable sources. Ex: Coal, Diesel, Nuclear activity materials etc. 2. Non-conventional sources (Renewable Sources) -these are non-consumable sources Ex: Solar, Wind, Tidal, Water etc. In India, the following sources are used to generate the power. 1. Water energy – It is used in Hydro-Electric Power Plant 2. Coal- It is used in Steam Plant 3. Diesel- It is used in I.C Engine plant 4. Nuclear activity materials- It is used in Nuclear Power Plant 5. Non-conventional sources- These are used in Solar, Wind & tidal power plant. RESOURCES OF POWER IN INDIA: The hydel power source plays a vital role in the generation of power, as it is a nonconventional perennial source of energy. Therefore the French cals it “huile Blanche”— white oil-the power of flowing water. Unlike black oil, it is a non-conventional energy source. A part of the endless cycle in which moisture is raised by the sun, formed into clouds and then dropped back to earth to feed the rivers whose flow can be harnessed to produce hydroelectric power. Water as a source of power is non-polluting which a prime requirement of power industry today is. The world’s total waterpower potential is estimated as 1500 million kW at mean flow. This means that the energy generated at a load factor of 50% would be 6.5 million kW-hr,
a quantity equivalent to 3750 million tonnes of coal at 20% efficiency. The world hydel installed capacity (as per 1963 estimate is only 65 million kW or 4.3% of the mean f l o w . India has colossal waterpower resources. India’s total mean annual river flows are about 1675 thousand million cubic meters of which the usable resources are 555 thousand million cubic meters. Out of total river flows, 60% contribution comes from Himalayan Rivers (Ganga, Indus and Brahmaputra). 16% from central Indian rivers (Narmada, Tapti and Mahanadi) and the remaining from the rivers draining the Deccan plateau (Godavari, Krishna and Cauvery). India’s power potential from hydel source as per the recent estimate is 41500 mW while its present hydel capacity is only 32000 mW. Still India has got enough hydel potential to develop to meet the increasing power needs of the nation. The abundant availability of water resources, its fairly even distribution and overall economy in developing this source of energy enhanced its development in India, The other factors responsible in its rapid development are indigenous technological skill, material and cheap labor. In the IX five-year plan; the Government considering the importance of this source has included a number of hydro-projects. The major difficulty in the development of hydroelectric projects is the relatively longer time required for its hydrological, topographical and geological investigations. Lack of suitable. Site is an added problem for taking up hydroprojects. Hydropower was once the dominant source of electrical energy in the world and still is in Canada, Norway and Switzerland. But its use has decreased in other countries since 1950s, as relatively less expensive fuel was easily available. In USA, only 10% of the total power production is water-generated. In the light of fuel scarcity and its up surging prices, the role of hydropower is again re-examined and more emphasis is being laid on waterpower development. As per Mr. Hays (Manager of Hydro Projects in USA), “It was less costly per mW to build a single 1000 mW thermal plant than 20 small hydro plants. But, with the increased fuel cost and high cost of meeting environmental criteria for new thermal plants, interest in hydro is being revived”. Small hydro-projects ranging from 10 to 1500 kW are becoming more feasible as standardization of major equipment reduces costs. India is yet to start in the field of micro-hydro projects, which is one major way for solving the present power problem. Hydro-projects generate power at low cost, it is non conventional, easy to manage, pollution free and makes no crippling demands on the transportation system. But the major drawback is, it operates at the mercy of nature. Poor rainfall has on a number of occasions shown the dangers of over dependence on hydropower. Let rivers flow and let rains shower the earth with prosperity is the ancient prayer chanted by Riches and continued to be chanted even now. The development of hydropower systems as a backup for thermal systems has significant advantages: The flexible operation of hydraulic turbines makes them suitable for. Peak load operation. Therefore, the development of hydropower is not only economical but it also solves the major problem of peak load.
The present Indian policy of power development gives sufficient importance for the hydel-power development. The next important source for power generation is fuel in the form of coal, oil or gas. Unfortunately, the oil and gas resources are very much limited in India. Only few power plants use oil or gas as a source of energy. India has to import most of the oil required and so it is not desirable to use it for power generation. The known resources of coal in India are estimated to be 121,000 million tonnes, which are localized in West Bengal, Bihar, Madhya Pradesh and Andhra Pradesh. The present rate of annual production of coal is nearly 140 million tonnes of which 40 million-tonnes are used for power generation. The coal used for power generation is mainly low-grade coal with high ash content (20-40%). The high ash content of Indian coal (40–50%) is one of the causes for bad performance of the existing steam power plants and their frequency outages, as these plants have been designed for low ash coals. Due to the large resources of coal available in the country, enough emphasis has been given for thermal Power plants in the IX plan period. The location of hydel-power plants is mostly determined by the natural topography available and location of thermal plants is dictated by the source of fuel or transportation facilities available if the, power plant is to be located far from coalmines. For nuclear power plant any site can be selected paying due consideration to safety and load. India has to consider nuclear generation in places remote from coal mines and water power sites. The states which are poor in natural resources and those which have little untapped conventional resources for future development have to consider the development of nuclear plants. The nuclear fuel which is commonly used for nuclear power plants is uranium. Deposits of uranium have been located in Bihar and Rajasthan. It is estimated that the present reserves of uranium available in country may be sufficient to sustain 10,000 mW power plants for its thorium into nuclear Indian lifetime. Another possible nuclear power source is thorium, which is abundant in this country, estimated at 500,000 tonnes. But the commercial use of this nuclear fuel is tied up with development of fast breeder reactor which converts energy economy must wait for the development of economic methods for using thorium which is expected to be available before the end of twentieth century. The major hurdle in the development of nuclear power in this country is lack of technical facility and foreign exchange required to purchase the main component of nuclear power plant. Dr. Bhabha had envisaged 8000 mW of power from nuclear reactors by 1980–81 which was subsequently scaled down to a more realistic level of 2700 mW by Dr. Sarabhai out of this only 1040 MW has materialized which is less than 1.5% of the country’s install ed power capacity. Moreover the performance of nuclear plants has been satisfactory compared to thermal plants.