municipal solid waste (msw) to energy
TRANSCRIPT
Municipal Solid Waste (MSW) to Energy
Presented ByAlam, Md TanvirID: 2015311947
Introduction
What is MSW ?
Definition: Waste generally means “something unwanted”. A material is considered as waste until it is considered as beneficial again. Thus a solid material considered as solid waste in the eye of producer when it loses its worth to them and is discarded.
Municipal Solid Waste (MSW) is the waste col-lected by urban local body
Composition of MSW
Income Level
Organic (%)
Paper (%)
Plastic (%)
Glass (%) Metal (%) Other (%)
Low Income 64 5 8 3 3 17
Lower Middle Income
59 9 12 3 2 15
Upper Middle Income
54 14 11 5 3 13
High Income 28 31 11 7 6 17
Types of waste composition by income level
Source: Waste Composition, World Bank
Chemical Properties of Waste Ultimate analysis of municipal solid waste ( percent by weight in dry basis)
Component Carbon (C) Hydrogen (H)
Oxygen (O) Nitrogen (N)
Sulphur (S) Ash
Food waste 49.1 6.6 37.6 1.7 0.2 4.8Paper 43.4 5.8 44.3 0.3 0.2 6.1Newsprint 49.1 6.1 43.0 0.1 0.2 1.5Cardboard 44.0 5.9 44.6 0.3 0.2 5.0Rubber 77.8 10.4 - - 2.0 9.8Plastics 60.0 7.0 23.0 - - 10PVC 45.2 5.6 1.6 0.1 0.1 47.4Leather 42.0 5.3 22.8 6.0 1.0 22.9Textile 55.0 6.5 31.2 4.5 0.2 2.6Wood 50.5 6.0 42.4 0.2 0.1 0.8Source: Kaiser (1978)
Proximate analysis and calorific value of MSWCompo-nent
Proximate analysis, % of weight Calorific value, kJ/kgMoisture content
Volatiles Fixed Car-bon
Ash As col-lected
Dry Moisture/ash free
Paper 10.2 76.0 8.4 5.4 15,750 17,530 18,650Newsprint 6.0 81.1 11.5 1.4 18,550 19,720 20,000Food waste 78.3 17.1 3.6 1.0 4,170 19,230 20,230Meat waste 37.7 56.3 1.8 4.2 17,730 28,940 30,490Grass 75.2 18.6 4.5 1.7 4,760 19,250 20,610Green Logs 50.0 42.2 7.3 0.5 4,870 9,740 9,840Plants 54.0 35.6 8.1 2.3 8,560 18,580 19,590Rubber 1.2 84.0 5.0 9.8 25,590 26,230 29,180Leather 7.5 57.1 14.3 21.1 16,770 18,120 23,500PVC 0.2 86.9 10.9 2.0 22,590 22,640 23,160Source: Kaiser (1978)
Why Waste to Energy ?
MSW to Energy Conversion Processes
Energy Conversion Processes
PyrolysisPyrolysis/GasificationConventional GasificationPlasma Arc GasificationMass Burn (Incineration)
Pyrolysis
Can be defined as thermal decomposition of carbon based materials in an oxygen deficient atmosphere using heat to produce syngas
No air or oxygen is present and no direct burning take place Thermal decomposition take place at elevated temperature ( 400-900 °C)
Process Schematic, MSW to Energy via Pyrolysis
Pyrolysis/Gasification
Pyrolysis/gasification is a variation of the pyrolysis process Another reactor is added whereby any carbon char or pyrolysis liquids produced
from the initial pyrolysis step are further gasified in a closed coupled reactor Air, oxygen or steam used for gasification reaction Temperature range: Pyrolysis zone: 400-900 °C Gasification zone: 700-1500 °C
Process Schematic, MSW to Energy via Pyrolysis/Gasification
MSW Preprocess-ing
Pyrolysis/ Gasifica-
tion Reac-tor
Ash/ Slag & Metals
Recyclables
Syngas
Syngas Cleanup
Byproducts such as sulfur & acid
gases
Air/O2
Air Emis-sions
Power genera-tion: Electrical Energy+ Steam
Electric-ity to Grid
Conventional Gasification A thermal process, which converts carbonaceous materials such as MSW into
syngas using a limited quantity of air or oxygen. Gasification conditions: 800-1600 °C Steam is injected into the conventional gasification reactor to promote CO and
H2 Production Some basic chemical reaction in gasification process are: C+O2=CO2
C+H2O=CO+H2
C+2H2=CH4
C+CO2=2CO CO+H2O=CO2+H2
C (n)+n H2O=n CO+(n+1/2m)H2
Process Schematic, MSW to Energy via Conventional Gasification
MSW Preprocess-ing
Conventional Gasifica-
tion Reac-tor
Ash/ Slag & Metals
Recyclables
Syngas
Syngas Cleanup
Byproducts such as sulfur & acid
gases
Air/O2
Power genera-tion: Electrical Energy+ Steam
Air Emis-sions
Electric-ity to Grid
Plasma Arc Gasification A high temperature pyrolysis process whereby carbon based materials are con-
verted into syngas Inorganic materials and minerals of the waste produce rocklike glass by product
called vitrified slag High temperature is created by an electric arc in a torch whereby a gas is con-
verted into plasma Operating temperature: 4000-7000 °C
Process Schematic, MSW to Energy via Plasma Arc Gasification
MSW Preprocess-ing
Plasma Arc Gasifica-
tion Reac-tor
Vitrified Slag & Metals
Recyclables
Syngas
Syngas Cleanup
Byproducts such as sulfur & acid
gases
Air/O2
Power genera-tion: Electrical Energy+ Steam
Electric-ity to Grid
Air Emis-sions
Mass Burn (Incineration)
A combustion process that uses an excess of oxygen or air to burn the waste
Operating temperature: 500-1200 °C High pressure steam produced in the fluid bed boiler
Process Schematic, MSW to Energy via Mass Burn (Incineration)
MSW Preprocess-ing Fluid Bed
Boiler
Ash & Metals
Recyclables
Gas Cleanup
Byproducts such as sulfur & acid
gases
Air/O2
Power genera-tion: Electrical Energy+ Steam
Electric-ity to Grid
Air Emis-sions
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