Poultry Litter as Renewable Energy Resource Using SOFC Technology

Transcription

1 Vol. 4 (213) No. 1, pp ISSN Poultry Litter as Renewable Energy Resource Using SOFC Technology K. Naresh, S. N. Ravi Teja, K Datta Sri Harsha Abstract We are in need of a non-conventional energy source from which we can extract energy for various purposes. This paper emphasizes on generating electricity by making use of poultry litter. Solid Oxide Fuel Cell (SOFC) is employed in the process of utilizing the hydrogen produced after gasification of the poultry litter thereby making it an economically viable, feasible and efficient process. Gasification, an incomplete combustion of biomass yielding hydrogen gas as a byproduct, provides an environment- friendly disposal option for the litter while providing heat, power, fuel and fertilizer. The heat produced here can replace the dependence of poultry farms on the fossil fuels and LPG gas to heat the broiler houses for the next batch of poultry to be grown. India being the third largest country in the production of poultry is now facing the problems of disposing the poultry waste and excess phosphorous in the farming lands. So by using SOFC technology, we can not only provide an effective way of proper disposal of poultry waste but also contribute our hand in meeting the growing power demand. Keywords Gasification; Solid Oxide Fuel Cell (SOFC); Poultry litter management; Renewable energy; Waste management. I. INTRODUCTION There has been a huge increase in energy demand during the last few decades, which resulted in the acceleration of the depletion of world s fossil fuel resources. So the time has come for us to depend on renewable energy resources instead of conventional resources. We here by emphasize on generating electricity by making use of poultry litter as the conversion of poultry litter to energy can, not only serve as a renewable energy source but also provides an alternative to land application in areas where poultry production is intensive. This will not only meet the growing power demand but can also provide an effective K. Naresh is currently working as Assistant Professor in department of Electrical and Electronics Engineering K. L. University, Vaddeswaram, Guntur, Andhra Pradesh, India. (Phone: ; knaresh@kluniversity.in). S. N. Ravi Teja is currently pursuing Graduate course in Electrical and Electronics Engineering K L University, Vaddeswaram, Guntur, Andhra Pradesh, India (Phone: ; rvteja5@live.com). K Datta Sri Harsha is currently pursuing Graduate course in Electrical and Electronics Engineering K L University, Vaddeswaram, Guntur, A.P, India (phone: ; harsha.kavuluri@gmail.com). way for the proper disposal of poultry waste thereby depicting a solution for a centralized waste management in poultry industry. There are a lot number of ways for achieving this purpose i.e., starting from the poultry litter to finally generating electricity. Here, we employ gasification technique followed by the Solid Oxide Fuel Cell (SOFC) technology which is one of the most effective processes available at present. II. MATERIAL VALUE OF CHICKEN LITTER Decades before nutrient-rich poultry litter was used as soil fertilizer in crop production, cattle feed and as a potting medium in growing ornamental plants. But however, the poultry litter has been banned as cattle feed by the Food and Drug Administration (FDA) due to concerns over Mad Cow Disease, coupled with increased restrictions on land applications, have intensified the problem of disposing poultry litter in an environmentally safe manner. Also, land applications of poultry litter in the agricultural fields are responsible for ground water pollution because of its high phosphorous content So all the possible ways of disposing poultry waste have been blocked due to environmental constraints. These reasons are jointly responsible for the use of poultry litter as a feedstock for bio-energy production. Poultry litter is a mixture of manure and bedding material such as wood shavings, sawdust, peanut hulls, shredded sugar cane, straw, and other dry absorbent low-cost organic materials. The table given below shows the material content in the poultry litter. Component Average Range Total Digestible Nutrient(TDN), % Crude Protein, % Crude Fiber, % Ash, % Calcium, %

2 Vol. 4 (213) No. 1, pp ISSN Phosphorus, % Dry Matter(DM)% Table 1: shows the material content in the poultry litter. III. POULTARY FARMS IN INDIA India is one of the largest producers of chicken in the world. India is the world s fourth largest producer of eggs and fifth largest poultry producer. India produces 2 billion poultry birds on 2, farms. Between 197 to 212 the annual per capita chicken meat available rose from 146 grams to 1.8 kilograms. Despite of the presence of diseases like bird flu, the poultry industry is estimated to have grown at 11% per annum during However, every industry requires the right focus to sustain this momentum. So we should see that, disposal of poultry litter should not be a barrier for the growth of poultry industry in India. Power generation from this poultry waste is considered as one of the best alternatives to the growing issue of poultry litter management. As an added advantage recent growth in energy costs and growing attention towards Greenhouse gas emissions have made poultry litter a viable green fuel source that can reduce the demand for fossil fuels and purchased electricity. This reduces the emission of carbon dioxide. Poultry litter has good burning qualities due to its composition, making it a potentially excellent source of fuel. The following table shows the statics of broiler meat production in India [4]. Source (foreign agricultural service, official USDA estimates [2]). Fig 1. Indian broiler meat production 199 to 212 IV. ELECTRICITY GENERATION FROM POULTRY LITTER Poultry Litter to electricity generation is the best environmentally friendly technique for waste management and power generation as well. This whole process takes place in mainly three steps. 1. Collection of Poultry Litter and extraction of hydrogen (producer gas) from the litter using gasification technique. 2. Generation of electricity by Solid Oxide Fuel Cell (SOFC) utilizing the hydrogen obtained in gasification and connecting it to the Statowned grid. 3. To produce manure from the residue of the litter. V. GASIFICATION A basic view of gasification is shown in the figure below. Fig 2. Process of Gasification Gasification is an incomplete combustion of biomass resulting in production of combustible gases consisting of Carbon Monoxide (CO), Hydrogen (H 2 ) and trace of Methane (CH 4 ). The combustion products from complete combustion of biomass generally contain nitrogen, water vapor, carbon dioxide and surplus of oxygen. However in gasification where there is a surplus of solid fuel (incomplete combustion), the product of combustion are combustible gases like Carbon Monoxide (CO), Hydrogen (H 2 ) and trace of Methane (CH 4 ) and non-useful products like tar and dust[3]. The production of these gases is by reaction of water vapor, and carbon dioxide through a glowing layer of charcoal. Thus the key to gasifier design to create conditions such that 1. Biomass is reduced to charcoal. 2. Charcoal is converted at suitable temperature to produce CO and H 2. Since any biomass material can undergo gasification, this process is much more attractive than Ethanol production or biogas where only selected biomass materials can produce the fuel. In this step poultry litter is collected and it is dried for the removal of moisture and for its fast burning. Then it is sent into combustion zone followed by reduction and collection zones. 915

3 Vol. 4 (213) No. 1, pp ISSN A. Combustion Zone Basic elements of Poultry litter are carbon, hydrogen and water but in different forms. In complete combustion we get carbon dioxide, water (steam) are obtained. As the combustion reaction is exothermic gives a theoretical temperature of 145C. The main reactions, therefore, are: C + O 2 = CO 2 (+ 393 MJ/kg mole) 2H 2 + O 2 = 2H 2 O (- 242 MJ/kg mole) B. Reduction Zone These partially combusted products (water, carbon dioxide and partially un-combusted Pyrolysis products) have to be passed through a red-hot charcoal bed where the following reduction reactions take place. C + CO 2 = 2CO ( MJ/kg mole) C + H 2 O = CO + H 2 ( MJ/kg mole) These reactions are main reduction reactions and being endothermic have the capability of reducing gas temperature. Consequently the temperatures in the reduction zone are normally 8-1C. Lower the reduction zone temperature (~ 7-8C), lower is the calorific value of gas. C. Collection Zone In this zone all the Carbon monoxide and Hydrogen is collected and then it is given the input to the Solid Oxide Fuel Cell (SOFC). VI. SOFC ELECTRICITY GENERATION Solid oxide fuel cells (SOFC) offer a low-pollution technology to electrochemically generate electricity at high efficiencies than the traditional ways available now. Advantages include efficiency, reliability fuel adaptability, and very low level emission of NOx and SOx. It also reduces the noise while producing electricity, which no other traditional method has ever done. A. Principle All the fuel cells of SOFC family work under the following principle. At the anode, the hydrogen molecule is split into hydrogen ions (protons) and electrons. The hydrogen ions permeate across the electrolyte to the cathode while the electrons flow through an external circuit and produce electric power. B. Working Fig 3. Mechanism of a Solid Oxide Fuel Cell SOFC creates electricity by making use of two electrochemical reactions. First, the anode strips electrons off the hydrogen molecules, making them hydrogen ions. At the same time, oxygen molecules flow across the cathode on to the other side of the cell [5]. As the electrons are stripped from the hydrogen molecules, they flow out through the anode and out of the cell to an electrical load. These electrons flowing from the anode to the electrical load are deposited at the cathode, where the oxygen molecules acquire them. This flow of electrons gives energy which can be used to power a machine. In fact, each oxygen atom acquires 2 electrons and carried them across the electrolyte. When the oxygen ions reach the anode, they react with the hydrogen to form water and other by products. Anode Reactions: 2H 2 4H + + 4e - Cathode Reactions: O 2 + 4H + + 4e - 2 H2O Overall Cell Reactions: 2H2 + O2 => 2 H2O 2CO + O2 => 2 CO2 {Producer gas CO+H2} However, these electrons get released back into the anode, which continues the flow of electricity. Hence, the byproducts of the reactions are water and carbon dioxide, excess chemicals and also a huge amount of heat. In fact, this heat can be used to make more electricity, while the water can be used to cool the machine powered by the fuel cell SOFCs run at extremely high temperatures, up to 1, digress Celsius. This high temperature is needed for the transfer of the oxygen molecules across the cathode and for the ionization of the molecules. The following table gives a comparison between the gasification and typical combustion processes. The results are from a power plant in Australia [5]. 916

4 Vol. 4 (213) No. 1, pp ISSN any ground water contamination as before. Fig 4. Working of SOFC VII. RESIDUE COLLECTION The left outs after the gasification can be collected and used as manure for the plants in land applications. The manure so obtained are less in phosphorous content, so there won t be VIII. CONCLUSION We here by conclude by saying that the project of utilization of poultry litter to generate electricity not only results in Environmental sustainability but also results in Socio, Economic and Technical sustainability s. A. Environmental Sustainability The project uses a renewable source of energy (poultry waste) for electricity generation and therefore does not emit additional greenhouse gases. Poultry litter which is currently being dumped near poultry farms is causing generation and release of methane into the the atmosphere, apart from causing local environmental problems such as odor, pest generation etc. Thus by avoiding dumping of the poultry litter, the project contributes to the environmental wellbeing and sustainability. B. Social and Economic Sustainability The project contributes to the economic development by generating additional employment and generation of an economic value to a waste. Thus the local unemployed residents as well as skilled manpower gets TECHNOLOGY COMBUSTION GASIFICATION PARAMETER POULTRY LITTER UTILIZED 1 Tons/Yr 1, Tons/Yr 5, Tons/Yr Heat Rate, Btu/kWh 15, 15, 15, Electricity , Produced, MWh Size of Plant, kw Heat Rate, Btu/kWh 18, 18, 18, Electricity , Produced, MWh Size of Plant, kw permanent employment due to the project activity and poultry farmers get additional revenue by selling the poultry litter to the power project. The project activity creates several permanent jobs as well as several indirect employment opportunities for collection, loading, transportation and unloading of biomass residues. The project activity creates various opportunities for rurally downtrodden people, contributes to remove social disparity by offering equal opportunities and reduces poverty to some extent. The project activity also contributes to the flow of investments in the rural area where the project is implemented. C.Technical Sustainability The proposed project implements an innovative renewable energy technology that is not widely practiced in our country except in some parts of Tamilnadu, Andhra Pradesh and Haryana. The project uses poultry litter as a fuel for power generation which was not tried earlier on commercial scale. Further the project not only contributes to increase the renewable energy share in the national grid system but also contributes to the removal of power fluctuations in the local grid system. REFERENCES [1] Influence of wood on the pyrolysis of poltry litter by Nii Ofei D. Mante. [2] News and views of clfma of India [3] Biomass Gasification by Anil K. Rajvanshi Director, Nimbkar Agricultural Research Institute, PHALTAN , Maharashtra, India (Published as a 917

5 Vol. 4 (213) No. 1, pp ISSN Chapter No. 4) in book Alternative Energy in Agriculture, Vol. II, Ed.D. Yogi Goswami, CRC Press, 1986, pgs ). [4] S. C. Singhal and K. Kendall, High Temperature Solid Oxide Fuel Cells: Fundamentals, design and Applications, Elsevier, Oxford, UK (23). [5] Availability of Poultry Manure as a Potential Bio- fuel Feedback for energy Production Prepared for the SC Energy Office 121 Main Street, Suite 43 Columbia, SC 2921 and the DOE/SSEB Southeast Biomass State and regional Partnership. 918