JOURNAL OF INFORMATION, KNOWLEDGE AND RESEARCH IN
MECHANICAL ENGINEERING
EXERGY EFFICIENCY ANALYSIS OF SOLID WASTE
1 SANJAY KAILA , 2 G.R SELOKAR , 3 AMITESH PAUL3
1 Department Of Mechanical Engineering, RGTU, SSSIST Sehore, MP-Bhopal
2 Principal Of Dept. Of Mechanical Engineering, RGTU, SSSIST Sehore, MP-Bhopal
3 Head Of Dept. Of Mechanical Engineering, RGTU, SSSIST Sehore, MP-Bhopal
,amitesh_paul @rediffmail.com
ABSTRACT: The world’s energy resources are finite and fast depleting has simulated interest in the efficient use of existing resources. This renewed interest has led to a greater emphasis on concepts of thermodynamics and apply these principles to improve industrial process efficiency. With this view the present paper is focus on to fulfill the energy thrust by converting solid waste into energy using batch type Pyrolyser in nitrogen gas atmosphere for cellulosic compositions by using various lignin cellulosic based materials wastes like newspaper waste, printing paper waste, card board waste. The exergy efficiency is different in case of different lignin cellulosic material due to their composition and the present of some chemical elements in each lignin cellulosic materials. The different efficiencies show that which waste material having better strength so that it can be used as a fuel and finally also calculated that if any lignin cellulosic material is being used in future as a fuel than how much energy extraction is possible from individual composition.
Keywords : Exergy Efficiency, Solid Waste (SW), Newspaper Waste, Printing Paper Waste, Card Board Waste
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1. INTRODUCTION
Municipal waste includes wastes resulting from municipal activities and services such as street waste, dead animals, market waste and abandoned vehicles. However, the term is commonly applied in a wider sense to incorporate domestic wastes, institutional wastes and commercial wastes.” Given by Michael becidan[1].
Because of rapid population growth and economic development in the country. The handling of Municipal solid waste encompasses planning, engineering, organization, administration, financial and legal aspects of activities associated with generation, storage, collection, transfer and transport, processing and disposal of municipal solid wastes in an environmentally compatible manner adopting principles of economy, aesthetics, energy and conservation. The magnitude of problem is per capita waste generation increasing by 1.3% per annum With urban population increasing between 3 – 3.5% per annum and yearly increase in waste generation is around 5% annually. India produces 42.0 million tons of municipal solid waste annually at present (India’s Population As per 2001 Census 1027 Million).Per capita generation of waste varies from 200 gm to 600 gm per capita / day. Average generation rate at 0.4 kg per capita per day in 0.1 million plus towns. Collection efficiency ranges between 50% to 90% of the solid waste generated. Urban Local Bodies spend around Rs.500/- to Rs.1500/- per ton on solid waste management of which, 60-70% of the amount is on collection alone 20% - 30% on transportation Hardly any fund is spent on treatment and disposal of waste Crude dumping of waste in most of the cities.
Figure 1 Average Values of Composition of solid waste in India,
Petit and Gaggroli [2] explained in detail the role of second law analysis for evaluating processes. In order to explain methodology of second law analysis and to calculate different losses due to irreversibility they carried out available energy analysis of coal fired boiler. They concluded that efficiency of boiler based on energy ratio (first law efficiency) is often misleading. Second law efficiency of coal-fired boiler is only 0.40 times first law efficiency. They emphasized the role of available energy analysis for optimization of design & accurate costing of flow stream.
M.S. Rao, S.P. Singh’ M.S. Sodha, A.K. Dubey, M. Shyamb [3] have discussed the mass, energy and exergy balance in case a counter current fixed-bed gasifier for municipal residue-based Refuse Derived Fuel (RDF) pellets and compared with the mass and energy performance features of gasifier with other biomass and residual fuels.
S.K. Som, A. Datta [4] have presented paper makes a comprehensive review pertaining to fundamental studies on thermodynamic irreversibility and exergy analysis in the processes of combustion of gaseous, liquid and solid fuels. The optimum operating condition in this context can be determined from the parametric studies on combustion irreversibility with operating parameters in different types of flames.
2. CONCEPT OF EXERGY
Exergy is defined as the maximum work potential of a material or of a form of energy in relation to its environment. This work potential can be obtained by reversible processes. However, in reality there are only irreversible processes. For practical reasons a reference environment has been defined for the environment. The reference environment is considered to be so large, that its parameters are not affected by interaction with the system under consideration. In this thesis the reference system as stated in Szargut et al [5] has been used with a reference temperature (T0) of 298.15 K and a reference pressure (P0) of 1 atm, unless otherwise stated. This system is similar to the one used by Kotas [6].
The concept of the control mass is not permitted to mix with the environment, or enter into chemical reaction with the environment components. It is this dead state which is of relevance in calculation of availability and has been employed by Keenan [7].
Caecilia R. Vitasari, Martin Jurascik, Krzysztof J. Ptasinski have included in the paper presents an exergy analysis of SNG production via indirect gasification of various biomass feedstock, including virgin biomass as well as waste biomass (municipal solid waste and sludge). The process is simulated with a computer model using the flow-sheeting program Aspen Plus. The exergy analysis is performed for various operating conditions such as gasifier pressure, methanation pressure and temperature. The largest internal exergy losses occur in the gasifier followed by methanation and SNG conditioning. It is shown that exergetic efficiency of biomass-to-SNG process for woody biomass is higher than that for waste biomass [8].
3. PROCEDURE TO OBTAIN PYROLYSIS PRODUCTS OF SOLID WASTE
Set the load cell at zero and take SW component as per pre-decided quantity (between 0-100 gm.)Put the sample into crucible. Purge the N2 gas with 5 lit/min into the reactor for first five minutes. Check availability of sufficient quantity of water in water tank supply on of the batch type Pyrolyser. Start the computer. Collect the oil in the flask. Collect gas in the balloon. Estimate the quantity of oil, gas and char collected from MSW component and analyze the oil, gas and char with the help of different analytical and experimental methods.
4. RESULTS OF EXERGY ANALYSIS
4.1 Using Card Board Waste Composition
Figure 2. Curves for Yields Products from Pyrolysis of Card Board Waste Material
Figure 3. Power Consumption w.r.t Temperature for Pyrolysis Process
Table 1. Ultimate Analysis of Card Board Waste Material
Ultimate AnalysisCarbon
(% wt.) / Hydrogen
(%wt.) / Nitrogen
(%wt.) / Sulfur
(%wt.) / Oxygen (%wt.) / GCV
( kJ/kg)
64.2 / 3.39 / 1.49 / 0.52 / 18.71 / 3893.91
Table 2. Proximate Analysis of Card Board Waste Material
Proximate AnalysisMoisture
(%wt.) / Volatile Matter
(%wt.) / Fix Carbon
(%wt.) / Ash
(% wt.)
5.28 / 70.99 / 11.94 / 11.69
Table 3. Ultimate Analysis Card Board Waste Material yield product
Ultimate AnalysisYield Product / C
(%wt.) / H2
(% wt.) / Nitrogen
(% wt.) / Sulphur
(% wt.) / Oxygen
(% wt.) / GCV
( kJ/kg)
Pyrolytic Oil / 43.75 / 5.55 / 0.01 / Absent / 49.90 / 1884.15
Char / 68.99 / Absent / Absent / Absent / 4.19 / 18004.1
Table 4. Proximate Analysis of Card Board Waste Material
Proximate AnalysisYield Product / Moisture
(%wt.) / Volatile Matter
(%wt.) / Fix Carbon
(%wt.) / Ash
(% wt.)
Pyrolytic Oil / 34.20 / 61.08 / 4.00 / 0.72
Char / 0.02 / 4.17 / 68.99 / 26.82
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Table 5. Gas Composition of Card Board Waste Material
Butane(%wt.) / Carbon
Dioxide
(%wt.) / Carbon Monoxide
(%y wt.) / Oxygen
(% wt.) / Ethane
(%wt.) / Propane
(%wt.) / Methane
(%wt.) / Nitrogen
(%wt.) / GCV
( kJ/kg)
ND / 2.88 / 6.989 / 2.38 / 4.08 / 2.15 / 12.008 / 69.522 / 3140.25
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The efficiency based on exergy is lower compare to efficiency based on first law of thermodynamic because in this case irreversibly of process is taking into account in terms of entropy.
4.2 Using Printing Paper Waste Composition
In case of printing paper due to present of ink which may behave like catalyst the energy consumption is lower but due presence of almost 5% moisture which also increases the energy consumption.
Table 6. Mass of MSW Composition (Printing Paper) and Yield Product
MSW Composition / Mass in GramReactants / Yield Products
Sample / Nitrogen / Char / Gas / Liquid
Printing Paper / 66.85 / 130.14 / 22.55 / 35.20 / 6.10
Table 7. Specific Heat (Cp) Of Printing Paper Waste Material And Yield Product
MSW Composition / Specific heat (kJ/kg-K)Reactants / Yield Products
Sample / Nitrogen / Char / Gas / Liquid
Printing Paper / 1.8 / 1.04 / 0.84 / 1.57* / 2.7
Figure 5.3 Curves for Yields Products from Printing Paper Waste
Table 8. Ultimate Analysis of Printing Paper Waste Material
Ultimate AnalysisCarbon
(% wt.) / Hydrogen
(%wt.) / Nitrogen
(%wt.) / Sulfur
(%wt.) / Oxygen (%wt.) / GCV
( kJ/kg)
66 / 3.2 / 0.47 / 0.48 / 18.65 / 5484.97
Table 9. Proximate Analysis of Printing Paper Waste Material
Proximate AnalysisMoisture
(%wt.) / Volatile Matter
(%wt.) / Fix Carbon
(%wt.) / Ash
(% wt.)
5.09 / 74.93 / 8.72 / 11.26
Table 10 Ultimate Analysis Printing Paper Waste Material yield product
Ultimate AnalysisYield Product / Carbon
(%wt.) / Hydrogen
(% wt.) / Nitrogen
(% wt.) / Sulphur
(% wt.) / Oxygen
(% wt.) / GCV
( kJ/kg)
Pyrolytic Oil / 43.59 / 5.89 / 0.03 / Absent / 49.95 / 2302.85
Char / 63.17 / Absent / Absent / Absent / 4.36 / 13021.57
Table 11 Proximate Analysis of Printing Paper Waste Material
Proximate AnalysisYield Product / Moisture
(%wt.) / Volatile Matter
(%wt.) / Fix Carbon
(%wt.) / Ash
(% wt.)
Pyrolytic Oil / 32.88 / 62.28 / 4.32 / 0.54
Char / 0.09 / 5.09 / 62.39 / 32.47
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Figure 4. Power Consumption w.r.t Temperature
for printing paper
Table 12 Gas Composition of Printing Paper Waste Material
Butane(%wt.) / Carbon
Dioxide
(%wt.) / Carbon Monoxide
(%y wt.) / Oxygen
(% wt.) / Ethane
(%wt.) / Propane
(%wt.) / Methane
(%wt.) / Nitrogen
(%wt.) / GCV
( kJ/kg)
ND / 10.61 / 12.49 / 2.2 / 4.72 / 5.4 / 41.16 / 23.42 / 14654.5
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4.3 Using News Paper Waste Composition
The exergy analysis procedure is same in case of newspaper waste because it is also lignin cellulosic material. The average energy consumption in case of newspaper waste is higher may be due to ink present or due to higher moisture content and its average value is 1.2 kW.
Table 13 Mass of MSW Composition (News Paper) and Yield Product
MSW Composition / Mass in GramReactants / Yield Products
Sample / Nitrogen / Char / Gas / Liquid
News Paper / 56.85 / 130.14 / 18.55 / 34.1 / 4.2
Table 14 Specific Heat (Cp) of News Paper Waste Material and yield product
MSW Composition / Specific heat (kJ/kg-K)Reactants / Yield Products
Sample / Nitrogen / Gas / Liquid
News Paper / 1.8 / 1.04 / 1.03* / 2.7
Figure 5. Curves for Yields Products of News Paper Waste Material
Figure 5.6 Power Consumption w.r.t Temperature for News Paper
Table 15.Ultimate Analysis of News Paper Waste Material
Ultimate AnalysisCarbon
(% wt.) / Hydrogen
(%wt.) / Nitrogen
(%wt.) / Sulfur
(%wt.) / Oxygen (%wt.) / GCV
( kJ/kg)
64.6 / 3.44 / 1.19 / 0.56 / 20.55 / 7117.9
Table 16. Proximate Analysis of News Paper Waste Material
Proximate AnalysisMoisture
(%wt.) / Volatile Matter
(%wt.) / Fix Carbon
(%wt.) / Ash
(% wt.)
6.11 / 73.92 / 10.31 / 9.66
Table 17. Ultimate Analysis News Paper Waste Material yield product
Ultimate AnalysisYield Product / Carbon
(%wt.) / Hydrogen
(% wt.) / Nitrogen
(% wt.) / Sulphur
(% wt.) / Oxygen
(% wt.) / GCV
( kJ/kg)
Pyrolytic Oil / 45.28 / 5.18 / 0.04 / Absent / 48.94 / 2763.42
Char / 76.12 / Absent / Absent / Absent / 3.28 / 1750.66
Table 18. Proximate Analysis of News Paper Waste Material
PROXIMATE ANALYSISYield Product / Moisture
(%wt.) / Volatile Matter
(%wt.) / Fix Carbon
(%wt.) / Ash
(% wt.)
Pyrolytic Oil / 30.42 / 65.05 / 3.97 / 0.56
Char / 0.04 / 3.42 / 75.94 / 20.60
Table 19. Gas Composition of News Paper Waste Material
Butane(%wt.) / Carbon
Dioxide
(%wt.) / Carbon Monoxide
(%y wt.) / Oxygen
(% wt.) / Ethane
(%wt.) / Propane
(%wt.) / Methane
(%wt.) / Nitrogen
(%wt.) / GCV
( kJ/kg)
ND / 6.19 / 6.58 / 3.2 / 0.27 / 0.01 / 1.26 / 82.49 / 837.4
The chemical composition of printing ink in case of newspaper waste is difficult to estimate and their chemical composition may not be same every time and their concentration may also vary due to font size and so due their thermal resistance the efficiency may get lower down.