Economic Generation Of Electricity

Economic Generation of Electric Energy By

V. ARAVAMUTHAN1 Retired Deputy Director Central Electrochemical Research Institute (CECRI), Karaikudi, India All rights reserved Published by: M/s Catalyst Management Services Private Limited, India (http://www.catalysts.org) May 2009 ISBN No: 978-81-908417-2-6

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The author Mr. V. Aravamuthan, aged 89, has been contributing articles for the advancement of Science and Technology for over six and a half decades (since 8 March 1943). Mr. Aravamuthan can be contacted at the following address - Flat No 7, II Floor, AKM Nest, Jawaharlal Nehru Street, T. Nagar, Chennai- 600 017, India. E Mail: [email protected]; Phone No: +91 44- 28140082. 2

This article has been shared with the libraries of Indian Institute of Science, Bangalore, India, and Connemara Library, Chennai, India, on the 20th of February 2009

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Economic Generation of Electric Energy Abstract It is an accepted fact that in electric energy generation release of carbon-di-oxide, oxides of Nitrogen and oxides of Sulphur should be avoided when utilizing even low grade coal with high as content, and/ or Sulphur contents and Methane from any source. Pollution of air and water must be avoided. Maximum use of solar heat energy with low cost appliances which can also be maintained/replaced, if need be, even by un skilled workers with simultaneous utilization of waste lands must be done. A suitable hybrid system should be utilised to generate electric energy continuously as replacement whenever solar heat energy could not be tapped. And top priority must be given to the utilization of inexaustable heat energy available from hot rocks continuously for millions of years in simple devices without any water, air and earth pollution. This article highlights ways of practicing these.

Main Article Coal, Methane, Solar light and heat energy and also the heat energy of hot rocks are the most important raw materials for large scale production of Electric Energy. A. UTILISATION OF COAL AND METHANE IN THE GENERATION OF ELECTRIC ENERGY It is possible to subject powdered coal having ash contents even well above 40% to latest physical methods of separation followed by chemical treatment (in which specific chemicals are used to react with the minerals in coal to form soluble products which can be separated from coal by filtration. The chemicals not only dissolve the minerals, but are also easy to regenerate and used in the cyclic process) to get ultra clean coal powder having below 0.05 percent ash. The cleaned coal can be utilized as indicated below at sites near to coalfields and also transported to distant places by pumping coal water- slurry and utilized. Employing carbon molecular sieves in a low energy consuming pressure swing adsorption process, oxygen from air (freed from moisture and Carbon dioxide) is obtained economically .Nitrogen is a valuable co product. To achieve maximum benefit in the utilization of heat content of 1) cleaned powdered coal and (2) Purified methane from Natural gas and or methane present in coal mines or biogas in the generation of Electric Energy without polluting the atmosphere with carbondioxide or Nitrogen, or Sulphur Oxides. I recommend that the powdery cleaned coal or purified methane is combusted in low cost oxygen in compact units and the hot combustion gas is used in the production of steam and then electrical Energy by the well established procedures. The waste heat of the exhaust combustion gas is utilized by well known procedures and finally concentrated carbon dioxide is collected in a compact chamber. I recommend that this carbon di oxide is continuously withdrawn in small optimum quantity and fed into large volume of water in a tower to get carbonic acid of the same concentration that is achieved in a tree robot 2

which removes carbon dioxide from atmospheric air. Optimum quantity of this carbonic acid is continuously withdrawn from the bottom of the tower and released to the earth. Fresh water in required amounts is continuously fed into the top of the tower. Thus the pollution due to carbon dioxide in the generation of electric energy from coal and methane is avoided. If the plant producing electric energy from coal or methane is located near sea coasts, the utilization of the waste heat from the exhaust combustion gas for desalination of sea water will be very economical. B. UTILISATION OF SOLAR LIGHT ENERGY IN THE GENERATION OF ELECTRIC ENERGY Although the utilization of solar light energy for the generation of Electric energy through the use of latest types of photovoltaic cell is well established in all places in the world, yet the indirect utilization stored solar light energy as biomass is also commercially very important in electricity generation. I recommend the production of pure methane from biomass and utilize the methane in the generation of Electricity as indicated earlier. Vegetation is bound to thrive by utilization and storage of solar energy from the sun. It reduces the levels of carbon dioxide and enhances the oxygen content in the atmosphere. Large amounts of annual agricultural wastes and human/animal refuse are available at a very low cost. These can be used as raw materials for the anaerobic digestion to get biogas. An excellent organic fertilizer is obtained as a co-product. Water hyacinth, a quick growing plant, can be extensively cultivated in sewage water with dissolved and suspended organic matter mixed with different kinds of industrial wastes. Even effluents from the tanneries can be used for hyacinth cultivation after necessary treatment with required amounts of sulphur dioxide to kill the bacteria and other harmful matter. The hexavalent chromium present in the effluent will be reduced to trivalent chromium. The solution is then reacted with ammonia and air to precipitate out chromium hydroxide along with ferric and aluminum hydroxides from any dissolved aluminum and iron values. The solution thus obtained is free from metal hydroxides and is used for hyacinth cultivation. The effluent from the water hyacinth ponds/canals is used for irrigation purposes. Biogas can be obtained from the portions of water hyacinth above 7 centimeters from the root portion as such or in admixture with animal or human refuse. The sewage and industrial wastewater contains harmful impurities like lead, cadmium and mercury and these are absorbed by hyacinth plants and stored up to 7 centimeters from the root. This portion is incinerated to get mixed metal oxides like lead, cadmium, mercury etc. In a tropical country like India with a vast sea coast and adjoining waste lands, Chosen varieties of marine algae cultivated in ponds and canals form a potential low cost raw material for continuous production of biogas. Hybrid varieties of sea algae such as synechocystis can be grown in ponds/canals. These algae have an ability to absorb carbon dioxide 4 to 5 times to

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those of tropical forests. The ponds/canals are to be fed with seawater and biogas sludge has to be added in proper proportions. A portion of by-product carbon dioxide resulting during the separation of methane from biogas when fed along with biogas sledge boosts the yield of algae. By a simple procedure, carbon di oxide can be separated from methane using potassium carbonate solution in a cyclic process The concentrated carbon di oxide resulting in the decomposition of potassium bicarbonate is collected in a compact unit. I recommend that this carbon dioxide is continuously withdrawn in small optimum quantity and fed into large volume of water in a tower to get carbonic acid of the same concentration that is achieved in a tree robot which removes carbon dioxide from atmospheric air. Optimum quantity of this carbonic acid is continuously withdrawn from the bottom of the tower and released to the earth. Fresh water in required amounts is continuously fed into the top of the tower. Thus pollution due to carbon dioxide in methane production from biomass is avoided. My recommendation to dispose off concentrated carbon dioxide as dilute carbonic acid to the earth is applicable to any industry were even moist carbon dioxide is available in a concentrated state. Hydrogen Sulphide can be separated from methane by passing it over activated carbon bed. The spent carbon is land filled. Replacement of active carbon is done normally once in four months. Pure Hydrogen can be produced economically from biomass through the intermediate production of pure methane thus. Pure Hydrogen in theoretical yields is obtained by cracking methane in molten iron in a cyclic process. The carbon gets dissolved in molten iron and is burnt off by injecting low cost oxygen. Heat thus released is greater than that required for cracking and the surplus heat can be utilized in a number of ways. This economic production of Hydrogen in a pure state from pure methane gas is also applicable to pure methane obtained from Natural gas or pure methane from coal mines. The heat recovered while cooling the hot pure hydrogen gas to room temperature is suitably used. The pure hydrogen gas at room temperature is employed to generate electric energy in a fuel cell. Salicorniabigelovil, which produces edible seeds can be economically cultivated in waste lands by utilizing the effluent from the sea algae pond or canal, biogas sludge and sea water. The edible seeds of salicornia bigelovil compare favourably with soya bean in oil and protein content. One hectare of salicornia bigelovil grown in waste land can replace one hectare of soyabean irrigated with salt free water. The leaves and the straw of salicornia bigelovil along with suitable agro wastes, animal and human refuse can be subjected to anaerobic digestion to get rich yields of biogas economically. It is not out of place to record here that the inexhaustible, cheap and abundant biomass, marine algae which surpasses any other known or to be developed device for the efficient and economical use of solar light energy, can produce biomass oil product equivalent to crude oil. Rich harvests of marine algae can be had on barren desert lands using sea water and feeding calculated amounts of biogas sludge and cheap byproduct carbon dioxide. Thus the need for

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the use of costly fresh water and valuable agricultural lands for growing corn and the like for bio fuel production is eliminated. Methane can be trapped in a bizarre material dubbed “dry water” a mixture of silica and water that looks and acts like a fine powder. The methane reacts with water to produce a crystalline material called methane gas hydrate in which individual methane molecules sit inside ice-like cages of water molecules. Thus methane can be stored and also transported to distant places economically by converting it into powdery form and is an attractive alternatives to pipe lines. C. UTILISATION OF SOLAR HEAT ENERGY IN THE GENERATION OF ELECTRIC ENERGY In a tropical country like India with abundant sunshine, very vast sea coast with adjoining waste lands and extensive desert area, I recommend the following procedure for the utilization of Solar thermal energy in the economic production of Electric Energy. Along with the sea coast and also in the desert plastic acrylic Fresnel lenses, which can be mass produced, are employed to focus sun’s rays intensely to heat several kilometers of black painted pipes containing hermetically sealed anhydrous chloride mixtures of sodium or potassium with aluminum or ferric in proper proportions. The anhydrous chloride mixtures remain in the liquid state from 300 degree centigrade to 750 degree centigrades and store the heat efficiently for several hours. This heat energy is utilized to produce steam and then electric energy by well established procedures. Whenever the stored solar heat system cannot supply the necessary heat to produce steam, a hybrid system can be employed substituting solar thermal energy by the heat energy derived from the combustion of clean coal or methane in low cost oxygen. The waste heat of the exhaust combustion gases is utilized by well established procedures. If the hybrid plant is located near the sea cost, the utilization of waste heat of the exhaust combustion gases is utilized economically in the desalination of sea water. D. UTILISATION OF THE HIGH TEMPERATURE HEAT ENERGY AVAILABLE IN ROCKS IN THE ECONOMIC GENERATION ELECTRIC ENERGY The inexhaustible high temperature heat energy available in rocks at great depths below the earth’s surface in many parts of the world, especially in U.S.A and Australia can be extracted as high pressure dry steam at high temperatures continuously for several millions of years economically employing the available technologies for reaching the desired depths below the surface of the earth utilizing water in a cyclic process. Mechanical and then electric energy is generated economically by well established procedures utilizing this high temperature high pressure steam.

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Establishing several large scale units in many parts of the world for the utilization of: • • •

Heat energy of hot rocks Concentrated solar heat energy and Stored solar light energy available continuously throughout the world as abundant low cost waste biomass and algae through the production of pure methane from them as indicated in this contribution for electricity generation.

This will serve to decrease considerably our dependency on fossil fuels, thus conserving fossil fuels and atomic energy for electricity generation. The electric energy generated economically by all the procedures indicated in this contribution is fed into electric grid and utilized for various purposes in any place. Large scale use of this electric energy in many systems of transport will help to maintain pollution free atmosphere in many parts of the world.

For Comments, Suggestions and Clarifications, write to: Mr. V. Aravamuthan, Flat No 7, II Floor, AKM Nest, Door No : &, Jawaharlal Nehru Street, T. Nagar, Chennai600 017, India. E Mail: [email protected]; Phone No: +91 44- 28140082 or send email to [email protected]

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