Pollution Control in Energy Conversion Processes 22nd April 2009 Children’s Club Lecture Current World – Characteristic Features Population Explosion Rapid Industrialization Urbanization What is Pollution? Ecological Imbalance 1. What are energy conversion processes? 2. In what way energy conversion processes lead to pollution? 3. What strategies need to be employed to make the individual energy conversion processes more user friendly and environmentally benign? Typical Energy Conversion Processes: From To Thermal Energy Mechanical Energy Electrical Energy Thermal energy Heat exchanger Steam turbine Thermo couple Mechanical energy Refrigerator, Gear box Electrical generators heat pump Chemical energy Furnace Diesel engine Fuel cell Nuclear energy Fission and fusion Nuclear Nuclear reactions steam turbine power plant The 1952 Tragic Episode of London Smog a b c (a) Degradation of a sandstone monument in the garden of The Danish Museum of Art and design, (b) Nelsons Column during the Great Smog of 1952 (c) Impact of the 1952 London Smog Upto 1000 tonnes of smoke particles, 2000 tonnes of CO2, 140 tonnes of hydrochloric acid and 14 tonnes of fluorine compounds. 370 tonnes of sulphur dioxide were converted to 800 tonnes of sulphuric acid Peak values of SO2 and smoke were estimated to be about 14, 000 μg/m2 Some Dangerous Pollutants Lead in Petrol Small Suspended Particulate Matter Photochemical smog Mobile Sources of Pollution Chlorofluro carbons (Ozone depletion) Pollution Control Strategy Vehicles with alternate fuels (carbon free fuels) Improving the efficiency of energy conversion process An eco-friendly car model assembled with plastic vehicle parts and proposed to run on alternate fuel Lead in Petrol Knocking problem: Knocking or detonation is the instantaneous explosive ignition of atleast one pocket of fuel/air mixture outside the flame front. Leaded gasoline was considered as one of the world’s greatest environmenta disasters Organolead compounds - On 9th December, 1921, Thomas Midgley Hydrocarbons and MTBE to increase the octane number – Carcinogens Strategy to get away with polluting fuel additives: Addition of 3 g TEL as well as 15% (by volume) ethanol were found to cause similar improvements in the fuel power Use of ethanol is a promising alternative to TEL Small Suspended Particulate Matter Small suspended particulate matter include PM10, PM2.5 and PM1 The origin of PM10 is from natural sources like the sea spray and mineral dust. Size of the particulate matter is an important parameter dictating the transport of the particles into the respiratory system and there by affecting the human health. Particles with size less than 2.5 μm are particularly harmful to people suffering from respiratory and cardio-pulmonary diseases. Such small particles (with diameter less than 2.5 μm) originate from car (diesel) exhaust. strategy to encounter the problem introduce filters in the exhaust Photochemical Smog The characteristic colouration of smog in California in the beige cloud bank behind the Golden Gate (The brown colouration is due to NOx) Mechanism of Photochemical Smog: NO2 + h NO + O. The reaction between CO and O. + O2 + M O3 + M OH. goes on producing NO2 O3 + NO NO2 + O2 which subsequently leads to the OH. + CO CO2 + H. accumulation of O3 HO2. + NO NO2 + OH. NO2 + h NO + O. O. + O2 O3 NO + O3 NO2 + O2 Accumulation of O3 cannot go on forever since the disturbed and undisturbed photolytic cycles are a function of position of sun in the sky, cloud shading and time (either day or night) Elevated ozone levels are generally seen in rural areas outside the cities where only little NO is present to transform O3 to O2 and NO2. The ozone levels are high during night and in the weekend when the traffic is low. At the country side the level of ozone is higher Photo chemical smog in Copenhagen Ozone Depletion O3 + Cl. O2 + ClO ClO + O. Cl. + O2 Ozone layer prevents the harmful UV-B radiation emanating from the Sun 1 % reduction in ozone layer increase the risk of non-melanomas (skin cancer) by 2 %. The first incidence of harmful impact of the depletion of ozone layer was reported in the middle of 1970’s It was not realized until, 1982, when the first indication of the degradation of ozone layer was observed, that human activity could influence ozone layer. neither the aeroplanes nor the NOx emissions emanating out of the planes have caused the depletion of ozone layer the main culprit was identified to be “Freon” and related compounds. Mobile Sources of Pollution Automobiles, particularly, cars are the mot important sources of air pollution. Unchecked growth in traffic causes air pollution, increases noise pollution, congestion and accidents. Strategies to check the growing traffic: Prohibit driving every second day based on the liscence number use of toll roads restricted parking places separate streets for pedestrians. Use of quality petrol and diesel with S contents of 50 ppm currently Strict legislation also must be made on the emission standards of NOx, non-methane VOC’s and small particles. Another important strategy to combat the emissions from mobile sources is to complete replace fossil fuel based energy sources with alternate clean fuels. Climatic changes through the changes in Ocean circulation Planetary scientists from European Space Agency, launched space satellite as part of the mission “Goce” the intention of knowing the details of causing the climatic change and to unearth the secrets of the planet earth The space ship will monitor the movements of ocean currents and track the changes in the earth gravity and yield data to detect of the flow of molten rocks From the study, the changes in ocean currents, the details of melting of ice-caps and volcanic processes can be understood Energy Conversion Processes – Land Mark Events S. No. Scientist Contribution Year 1 Thomas Newcomen Atmospheric engine using steam (first widely used heat engine) 1700 2 James Watt 1765 1. Separate steam condenser idea 2. First Boulton and Watt condensing steam engine 3 John Barber Gas turbine ideas 1791 4 Benjamin Thompson (Count Observation of conversion of mechanical energy to heat while boring cannon 1798 Rumford) 5 Robert Fulton First commercial steam boat 1807 6 Robert Stirling Stirling engine 1816 7 N. l. Sadi Carnot Principles for an ideal heat engine 1824 (foundations of thermodynamics) 8 Michael Faraday First electric current generator 1831 9 Robert Mayer Equivalence of heat and work 1842 10 James Joule 1847 1. Basic ideas of the first law of thermodynamic 1849 2. Measured the mechanical equivalent of heat 11 Rudolph Clausius Second law of thermodynamics 1850 12 William Thompson Alternate form of the second law of thermodynamics 1851 (Lord Kelvin) 13 Etienne Lenoir Internal combustion engine with out mechanical compression 1860 14 A. Beau de Rochas Four stroke cycle internal combustion engine comcept 1862 15 James C Maxwell Mathematical principles of electro magnetics 1865 16 Niklaus Otto Four – stroke cycle internal combustion engine 1876 17 Charles Parsons Multistage, axial-flow reaction steam turbine 1884 18 Thomas Edison Pearl street steam-engine driven electrical power plant 1884 19 Albert Einstein Mass energy equivalence 1905 20 Otto Hahn Discovery of nuclear fission 1938 1. Thomas Newcomen (1664 – 1729): Energy conversion device: Atmospheric steam engine, 1700 Thomas Newcomen was born in Dartmouth, Devon, England. His native place was known for tin mines. The mining depth of the tin mines was limited by the frequent floods. Thomas Newcomen invented the first practical steam engine for pumping water which was latter known as Newcomen steam engine or atmospheric steam engine. He was regarded as the fore father of industrial revolution 2. James Watt (1736 – 1819): Energy conversion device: First Boulton and Watt condensing steam engine James Watt was a Scottish inventor and a mechanical engineer. His improvements to steam engine in one way have contributed to the industrial revolution. The English Novelist Aldous Huxley (1894 – 1963) wrote about James Watt‟s invention of steam engine as follows: “To us the moment 8:17 AM means something – something very important, if it happens to be the starting time of our daily train. To our anscestors, such an odd eccentric instant was with out significance – did not even exist. In inventing the locomotive, Watt and Stephenson were part inventors of time.” At an young age of 18, Watt has lost his mother and his father‟s health deteriorated and life became troublesome and challenging to young Watt. After great struggle, Watt as granted with an opportunity to set up a work shop in 1758, at the University of Glasgow, by three professors. One among them, Prof. Joseph Black became friend to James Watt. At the university, in the work shop, James Watt has read all that he could read about steam engines. He has learned that the Universtiy owned a model of Newcomen engine which was then under repair. Initial experimentations with the Newcomen engine showed that about 80 % of the heat energy from the steam was lost in heating the cylinder containing the piston where in there is a provision for the condensation of steam by injection of a stream of cold water. He proposed an excellent idea of condensing the steam in a separate chamber apart from the piston and cylinder As a result of the temperature of the cylinder could be maintained at the same temperature as that of the injected steam. But the transfer of steam from the cylinder to the condenser remained a question which was later solved by generating vacuum in the condenser which has facilitated the sucking of steam from the cylinder into the condenser. Thus, condensing steam engine formed the key innovation of the industrial revolution which has changed the world of work 3. John Barber (1734 – 1801): Energy conversion device: First Gas Turbine John Barber was a well known English inventor. He is coal master by profession. Gas turbine was the most remarkable among his many inventions. The principle of Barber‟s turbine was based on generating gas by heating wood, coal, oil or other substances in a retort. The gases are then conveyed into a receiver and cooled. The gases as well as air are separately compressed in different cylinders and pumped into an “exploder” also called as combus tion chamber. Water was injected into the explosive mixture. The mouth of the combustion chamber is cooled. In addition, Eventhough nothing practical has come out of his patent pertaining to “Gas Turbine” for sure the principles proposed for the first time formed the basis for the working model of modern turbine. He was the first to design the gas turbine. The thermodynamic cycle which was exploited by him is being currently used in the modern gas turbine. The design consisted of a compressor, a combustion chamber and a turbine which are the integral and vital components of to gas turbine. The purpose of gas turbine is to generate motive power and using the same for obtaining motion and facilitating metallurgical operations. The invention of gas turbine was analogous to propelling a horseless carriage. The machine contained a simple chain driven reciprocating gas compressor, a combustion chamber and a turbine. In spite of the fact that the concepts and ideas of Barber pertaining to the gas turbine were sound, with the available techn ology of th day no sufficient power could be generated for compressing the air and the gas and to produce useful work. His intellectual ideas have lead to the origin of the modern gas turbine. 4. Benjamin Thompson, Count Rumford (1753 – 1814) Outstanding Observation: Conversion of mechanical energy to heat In the words of Benjamin Thomson about his invention of the generation of heat from friction, “It would be difficult to describe the surprise and astonishment expressed in the countenances of the bystanders, on seeing so large a quantity of cold water heated and actually made to boil with out any fire.” Benjamin Thompson was born on 26th March, 1753 at Woburn Massachusetts. He was a renowned Anglo-American inventor and well known Physicist of all times. His contributions to science have brought revolution in the field of thermodynamics in the early part of 19th century. The most important work of Benjamin was pertaining to the nature of heat. He got wide acclaim for his observation of the generation of heat by friction during the boring of cannon at the arsenal in Munich. Experiments were carried out by immersing the cannon barrel in water using a blunt boring tool. It was shown that the water could be boiled with in roughly two and a half hours. In addition the supply of frictional heat was found to be inexhaustible. No further attempt was made to measure the mechanical equivalent of heat . In addition to his pioneering work on “heat”, Benjamin has also concentrated on the concept of light and succeeded in the invention of “photometer‟. The standard unit for the luminous intensity, „candle‟, which was subsequently termed as „candela‟ was introduced. The standard „candela‟ was deduced from the use of oil of sperm whale. Benjamin Thomson has termed heat as a form of motion. Benjamin Thompson is credited with the invention of the thermal ware beneficial for cold climatic conditions Thomson has investigated the insulating properties of fur, wool and feathers and proposed that the insulating properties of the afore mentioned natural materials are because of their ability to inhibit the convection of air. 5. Robert Fulton Energy conversion device: First commercial steam boat Robert Fulton was an American Engineering, inventor and a well known artist. He was born on 14th November, 1765 at Pennsylvania. Most important of his scientific achievements is the invention of steam boat, Clermont The Clermont was able to travel a trip of 300 miles in 62 hours between the New York city and Albany, New York when tested on Hudson river on 14th August, 1807. The boat was 20.1 m long, 2.4 m. Initial efforts on the practical utility of the steam boats were futile with the sinking of the steam boat first run on the Seine in Paris in 1803. Robert Fulton became so renowned that he was even commissioned by Nepoleon Bonaporte in 1800 to design a submarine, Nautilus, the first practical submarine in history. Incidentially, In the very year of the birth of Robert Fulton, 1765, James Watt‟s new invention of steam engine with a separa te condenser came into existence as a result of which the efficiency of the steam engine is quadrupled. 6. Robert Stirling (1790 – 1878) Energy conversion device: Stirling Engine Robert Stirling, born on 25th October 1790, was a Scottish clergy man. He is the inventor of stirling engine. The first practical version of the stirling engine was built in 1818 to pump water from a quarry. The work of Sadi Carnot (1796 – 1832) facilitated the understanding of the stirling cycle. The uniqueness of stirling engines lie in their high efficiency. The theoretical efficiency of stirling engines is close to the Carnot cycle efficiency (theoretical maximum efficiency). In fact, Robert Stirling, has called his invention by name, “economizer” (regenator) based on its function. The term „stirling engine‟ was coined by Rolf Meijer. The operation of stirling engine is based on the expansion and compression of the working gas, contained in the working chamber, when heated and cooled respectively. The stirling engine containing a fixed amount of gas which is made to move back and forth between cold end (at room temperature) and hot end (heated by kerosene or any other combustible material). The gas is made to move between the two ends by the displacer piston. The internal volume is changed by the „power piston‟ when the gas expands and contracts. Currently stirling engines (improved versions) are being investigated at NASA to be employed for powering space vehicles by employing solar energy as heat source [23, 24]. What is a stirling engine? Stirling engine is known for its silent operation, longevity of performance, improved milage and reduced pollution. Stirling engine is a promising automobile engine. Further advancements in the performance of stirling engine for automobile applications are anticipated by Jet propulsion lab (California Institute of Technology), Energy research and development administration (ERDA, US), Ford motor company (American multinational company and the world’s fourth largest automaker). Sweden is on the way to develop stirling engines suitable for delivary vans and other heavy duty vehicles. Stirling engine is an external combustion engine similar to the old workhorse of the industrial revolution, the steam engine. The heat required for its operation is obtained from outside the working cylinder rather than from inside. Stirling engine is unique in a way that any source of heat like concentrated solar energy, nuclear energy, kerosene, coal, steam, saw dust or any combustible material can be used as heat source. More amount of power can be generated with a given amuont of fuel in the case of stirling engine. Practically no emissions of CO or unburnt hydrocarbons or NOx are produced under stirling conditions. In the internal combustion engine (ICE), combustion of fuel and oxidizer (air) occurs in the combustion chamber. The gases produced during combustion which are at high temperature and pressure apply force on the movable components (piston or turbine blade) and move the components over a distance and generate useful mechanical energy. Some examples of ICE’s include four-stroke piston engine, two stroke piston engine, Wankel rotary engine, gas turbine, jet engine and rocket engine 7. N. L. Sadi Carnot (1796 – 1832) Scientific Contribtions: Concepts of Carnot’s efficiency, Second law of thermodynamics Sadi Carton is regarded as the Father of thermodynamics owing to his rich contributions like the concepts of Carbot efficiency, Carnot theorem, Carnot heat engine and several others. Nicolas Leonard Sadi Carbot was born in Paris on 1st June, 1796. He was a well known French Physicist and military engineer. In the year, 1824, he has compiled a 65 page book on “Reflections on the motive power of fire”. The book is regarded as the founding and fundamental work in the science of thermodynamics. He has put forward the first successful theoretical account of heat engines which was subsequently came to be known as „Carnot cylce‟. He has laid foundations for the second law of thermodynamics. He has outlines the second law of thermodynamics as “the motive power is due to the fall of caloric heat from a hot body to a cold body”. The second law of thermodynamics was put into mathematical form by Clausius who has also introduced the concept of „entropy‟. After his graduation, Sadi Carnot became an officer in French army. After the final defeat of Nepolean in 1815, Carnot took permanent leave from the French army and has spent his time committing himself to scientific research. Unfortunately, Carnot passed away at an early age of only 36 years in 1832 due to cholera epidemic. Most of his belongings and writings were buried together with him after his death for fear of cholera. Only very few of his scientific contributions survived in addition to his book “Reflections on the motive power of fire” Michael Faraday (1791 – 1867) Energy conversion device: First electric current generator Michael Faraday was born on 22nd September 1791 in England. He is a gifted natural philosopher, well known British Chemist and Physicist. He made rich contribution to the fields of electromagnetism and electricity. In 1831 Faraday discovered Electromagnetic induction which formed the basis for electric transformer and generator. His name “Farad” was given to the unit of electrical capacitance. He was one of the most influencial scientists in the history of mankind. He is regarded as the best experimentalist in the history of science. Michael Faraday was one among the four children belonging to a family which is not financially well off. At the young age of 14 he was forced to join as an apprentice with a local book binder There he got an opportunity to get himself acquainted with the writings of many great scientists through reading of several books which was his favourite passion. He was inspired by the book “Conversations in Chemistry”, by Jane Marcet and developed deep passion for Science at an young age. At a very young age of 20, in 1812, he was privileged to attend the lectures by Humpry Davy at the Royal Institution and Royal society. Faraday subsequently has written to Davy seeking a job with Davy but his request was turned down initially. Faraday did not lose his determination to join and work with Davy. Now Faraday sent Davy a book with three hundred page containing the notes prepared based on the lectures delivered by Davy and pleaded for job with Davy. This time Davy‟s reply was immediate, kind and favourable. During this time, unfortunately, Davy has lost his eye sight in an accident with nitrogen trichloide. Davy employed Faraday as his secretary and chemical assistant. In fact Davy has commented that “the most valuable among his inventions is the discovery of Faraday”. Michael Faraday is an outstanding scientific lecturer of his time. He was the founder of the Royal Insititution‟s Friday evening discourses. In the same year, 1826, he initiated a lecture series for children by name “Christmas Lectures”. For nineteen consistent years between 1826 and 1860, Faraday was successful in delivering the Christmas lecture series. 9. Julius Robert von Mayer (1814 – 1878) Scientific contribution: Numerical value for the Equivalence of work and heat Julius Robert von Mayer is a German Physicist of high intellectual caliber. He was born at Heibronn, Wurttembert (currently known as Germany) on the 25th of November 1814. He was the propounder of the „first law of thermodynamics‟. Julius Robert von Mayer calculated the numerical values of the mechanical (dynamical) equivalent of heat in the year 1842. Even though work and heat are different forms of energy, they are interconvertable and can be transformed from one form to the other. His calculations of the numerical value for the mechanical equivalent of heat were based on the work done by a horse in stirring paper pulp in a Cauldron. According to Julius Robert‟s calculations the value of mechanical equivalent of heat is 425 kgf.m/kcal which is in close agreement with the modern day values of 426.6 kgf.m/kcal (for the terhmochemical calorie) and 426.9 kgf.m/kcal (for the international steam table calorie). Even though Julius Robert Mayer has adopted indirect means for the measurement, the value obtained was free from error and exactly matched with the value experimentally determined by James Prescott Joule after years of hackbreaking and painstaking direct experimental studies. Even though Mayer has published the afore mentioned result five years earlier than James Joule, the credit of discovering the relationship between mechanical work and heat and the numerical value of the mechanical equivalent of heat was attributed to James Joule. It is an unfortunate development that the credit for the discovery of the numerical value of mechanical equivalent of heat was given to James Joul rather than Julius Robert Mayer. Mayer was the propounder of the first law of thermodynamics. He was considered as one of the founding fathers of thermodynamics. He is the first to enunciate the law of conservation of energy which states that energy can be neither created nor destroyed and this law was subsequently became well known as the first law of thermodynamics. Mayer was the first scientist to propose that the vital chemical processes (now known as oxidation) are the primary source of energy for all the living creatures. Mayer was the first to identify that the process of conversion of light into chemical energy by plants. Mayer went through several tribulations of life including forgoing the credit of his painstaking calculations of the mechanical equivalent of heat to James Joul. In addition, he has lost two of his children in rapid succession in 1848 which has added to his grief. From the shocking situations he has gone through in life, Mayer has attempted suicide and became mentally sick and was even confined to mental hospital for some time. Even though he was released from the mental institution after a while, he was a broke man by then and only re-entered in to public life timidly from then. Julius Robert von Mayer passed away on 20th March 1878 after battling with tuberculosis 10. James Prescot Joule (1818 – 1889) Scientific Contributions: (i) Basic ideas of the first law of thermodynamic (ii) Measured the mechanical equivalent of heat James Prescot Joule was born on 24th December 1818 in Salford, England. He was a brewer (one who’s occupation is to prepare malt and liquor) by profession. He is a renowned English Physicist. He was an accurate, resourceful and gifted experimentalist. Joule was the pupil of the famous English scientist John Dalton. John Dalton taught Chemistry, Physics and mathematics between 1934 and 1937. Joule has proposed a relationship between heat and mechanical work. The relationship of mechanical equivalent of heat has subsequently led to the concepts of law of conservation of energy and to the first law of thermodynamics. Joule was only met with many stumbling blocks, discouragements, unenthusiastic response and silence from the established scientific communities (like the British Association for the advancement of science, Cork) of his time He remained undaunted and sought mechanical demonstration of the conversion of work into heat. Joule has proposed the possibility of inter conversion of work (energy) and heat. The mechanical power derived by turning a magneto-electric machine by the passage of electric current through its coils is converted into heat. In an analogous manner, the heat generated in the battery working on a variety of chemical reactions is converted into the motive power of the electro-magnetic engine. In 1843, Joule calculated the amount of mechanical work needed to produce an equivalent amount of heat which was subsequently called as “the mechanical equivalent of heat”. In one of his best known experiments in 1845, Joule estimated the mechanical equivalent of heat to be 4.41 J/cal) The experiment comprises of measuring the raise in the temperature of water placed in an insulated barrel from the work done by the falling weight in spinning the paddle - wheel placed in the insulated barrel containing water. The value of mechanical equivalent of heat was subsequently refined in 1850 and was reported as 4.159 J/cal. The afore mentioned value was close to the estimates of 20th century 4.15 J/cal. Joule was the first to estimate the velocity of gas molecules (1848, Kinetic theory of gases). Apart from work and heat, Joule’s studies were also extended to the concepts of temperature, current and resistance. His work with William Thomson (came to be known as Lord Kelvin) bore fruit in devising the absolute scale of temperature. The observation of the decrease in temperature as the gases expand with out the performance of any external work formed the basis for the development of refrigeration industry. The process of cooling of gases when they expand was subsequently known as “Joule – Thomson Effect”. His studies on current and resistance lead to the proposal of Joule’s law (1840). According to Joule’s law, the amount of heat produced (P) per second in a current carrying wire is proportional to the square of the current multiplied by the resistance (R) of the wire. P I2R Joules efforts and contributions to energy conversion processes, related to heat and mechanical motion, were recognized. The SI unit of energy was named after him as “Joule” in his honour 1.11. Rudolph Julius Emanuel Clausius (1822 – 1888) Scientific Contributions: Second law of thermodynamics, Concept of Entropy Clausius was born at Koslin, Prussia, Germany on 2nd January, 1822. Clausius was a nenowned German Physicist, mathematician, founding thermodynamicist and the originator of the concept of entropy. His doctoral studies were related to the optical effects in the earth‟s atmosphere. Clausius has proposed that the blue colour of the sky during day time and the red shades in the sky during sunset are because of the reflection and refraction of light. Lord Reyliegh has subsequently shown that the different shades and colours of sky during the sun raise and the sun set are because of scattering of light rather than reflection or refraction as suggested by Clausius. In spite of this descrepency, Clausius work is commandable owing to the advanced mathematical approach Clausius has used compared to his predecessors. One of the six brothers of Calusius, Rudolf Clausius wrote about Clausius as follows: “All those intimate with Clausius esteemed his reliability and truthfulness. Greatest trust and confidence were placed in hi m. His judgement was highly valued. His burning patriotism did not permit him to stay idle at home during the Franco-Prussian war of 1870-1871. He formed the ambulance Corps team with the students of Bonn and extended services to the wounded soldiers. At the great battles of Vionville and Gravelotte he helped to carry the wounded from the battle and lessened their suffering. He continued to work upto his final illness and even on his last sick-bed he held an examination. C alusius breathed his last on 24th August, 1888 12. William Thompson (Lord Kelvin) Scientific Contribution: Alternate form of the second law of thermodynamics Thomson was born on 26th June 1824 in Belfast, Ireland. He was a well known distinguished British scientist, mathematical physicist and an engineer. is life is a wonderful record of strenuous and successful scientific work. Thomson’s most remarkable contribution to science is the development of Kelvin scale of absolute temperature measurement. In recognition to his achievement he was honoured with the title, „Baron Kelvin‟. So Thomson was often called by name Lord Kelvin. Infact the title “Kelvin” refers to the river Kelvin which flows across the university of Glasgow, Scotland where he was a professor of Natural Philosophy from 1846 onwards. Lord Kelvin met Joul in 1847 and their scientific association remained fertile leading to many interesting scientific inventions Joule-Thomson effect: when a compressed gas is allowed to pass through a narrow orifice, the gas undergoes a slight degree of cooling. Based on this principle only Dewar could subsequently liquefy hydrogen. I Lord Kelvin has enunciated the principle of the dissipation of energy. According to the principle, out of the energy (in the form of heat) taken in by the heat – engine only a portion is converted into mechanical work and the rest of the energy is dissipated or degraded or wasted and thus there is a universal tendency of the dissipation of mechanical energy. Ocean telegraphy or submarine cable telegraphy He proved that the speed at which signals pass through a long submarine cable decreases in proportion to the square of its length. He described the advantageous conditions for signal transmission and designed instruments that enabled the required conditions realizable. Lord Kelvin suggested that feeble currents as well as sensitive receiving instruments need to be employed for making signal transmission in submarine possible and to achieve this end he has invented mirror galvanometer. The mirror galvanometer comprises of a magnet suspended by a fine fibre. The magnet carries a tiny mirror which is meant for reflecting the light and magnifying the moments of the magnet. In most cases the mirror and the magnet are of the weight of only a grain. Extreme sensitivity in signal transmission is achieved by the use of mirror galvanometer. With enthusiasm and untiring energy Lord Kelvin has devoted himself to the advancement of science and knowledge. Lord Kelvin breathed his last on 17th December, 1907 Energy Conversion in Fossil Fuels: Metamorphosis of vegetal matter into coal Various Energy Sources Energy Sources Chemical and Physical (photo) energy Thermo mechanical energy Atomic Energy Oxidation of reduced substance (hydrocarbon) Generation of heat or Wind, water, ocean and Energy from the splitting of electricity by absorbing geological sources heavy nuclei (U235) sunlight Fusion of light nuclei (1H or 2H) Energy involved is of the Energy involved is of the order of order of meV few eV Energy involved is of the (water falling from several (equivalent to that of a chemical order of 10 6 eV 10’s of meters height) bond) (MeV) per nuclear reaction World energy consumption – Major energy sources S. No. Energy Source Energy Consumption (in quads) 1 Petroleum 149.7 2 Natural gas 87.3 3 Coal 84.9 4 Nuclear 25.2 5 Hydro, geothermal, solar, wind and other renewables 377.0* *Total world energy production – 377.1 quads 1 quad = 1015 British thermal units = 2.9 x 1011 kwh Energy flow diagram for the United States for 1999 (in quads; 1 quad = 1015 British thermal units) World reserves of fossil fuels S. No. Energy source Reserve Consumption 1 Coal 9.1 x 1011 tonnes 4.5 x 109 tonnes 2 Oil 1.6 x 1014 l 1.2 x 1010 l/day 3 Natural gas 1.4 x 1014 m3 2.4 x 1012 m3/year (gross production) Combustion of Fuels as Source of Energy Pictorial representation of Bomb Calorimeter Major sources of CO2 World wide CO 2 production from man-made sources Source Gt CO2 Coal 9.0 Oil 9.4 Natural gas 3.6 Cement Manufacturing 0.6 Deforestation and land exploitation 7.4 Total 30.0 i. Generation of electricity and heat for industry resulting in flue gas emissions from ii. stationary combustion process ii. Exhaust gases from automobiles iii. CO2 emissions from natural gas and coal seam gas iv. Metallurgical process involving smelting of Al and production of iron and steel Principal CO2 capture technologies include : a. Absorption b. Adsorption c. Membrane Separation d. Cryogenic separation RECYCLING OF CO2 – PRODUCTION OF INDUSTRIAL CHEMICALS FROM CO2 Concepts for (a) closed and (b) open loop thermochemical heat-pipes Conclusion: Owing to the high energy density and availability fossil fuels are expected to be the major energy source to be exploited for a variety of energy conversion processes in the next few decades of the 21st century. Correspondingly the CO2 emissions into the atmosphere continue to raise worsening the situation. Strategies evolved to check the CO2 emissions from man-made sources need to be strictly implemented with out bias. Irrespective of the energy source, almost all energy conversion processes, involving either renewable energy sources like solar, wind and tidal energy, nuclear fuels like U235, Th232, biofuels like biodiesel and electrochemical energy conversion devices like fuel cells, energy storage devices like batteries, result in pollution in varying magnitudes in one way or other.