Thermal Processing of Solid Waste

This presentation deals with all the types of Thermal Processing Techniques as used for the Processing of Solid Waste

1. PROCESSING OF SOLID WASTE (BIOLOGICAL PROCESSING,CHEMICAL PROCESSING, THERMAL PROCESSING ) THERMAL PROCESSING OF SOLID WASTE Prof.Vaibhav D.Kamble (BE CIVIL, ME Civil – Environmental Engineering)

2. PROCESSING OF SOLID WASTE (BIOLOGICAL PROCESSING,CHEMICAL PROCESSING, THERMAL PROCESSING )

3. THERMAL/CHEMICAL PROCESSING OF SOLID WASTE Main Focus on System analysis and not on the design details

4. CHEMICAL/THERMAL PROCESSING Thermal Processing- volume reduction & energy recovery Definition-Conversion of solid waste into gaseous, liquid or liquid conver sion products with subsequent release of heat energy

5. INCINERATION Common method of thermal processing of solid waste Incineration is the combustion of waste in a controlled manner in order to destroy it or transform it into: less hazardous less bulky more controllable constituents

6. OBJECTIVES OF INCINERATION Volume reduction Stabilization of waste Recovery of energy from waste Sterilization of waste

7. ADVANTAGES OF INCINERATION T he volume & we i ght of t h e waste a r e re d u c e d to a fraction of its original size Waste reduc t io n i s imme d ia t e , doe s n o t re q uire long term residence Waste can be incinerated on site without carried to a distant area A i r dischar g e ca n be ef f ec tivel y c o ntrol l e d for minimal impact on the atmospheric environment The ash residue is non putrescible or sterile Technology exist to completely destroy even most hazardous material in a complete effective manner Relatively requires small disposal area compare to land burial By using heat recovery technique the cost of operation can often be reduced through the use or sale of energy

8. PRODUCTS OF INCINERATION Gaseous Products-CO2,H2O,SO2 & N2 Solid residue- Non – combustibles Fly Ash – must be removed from the gases to avoid air pollution

9. COMBUSTION & PROVISION OF OXYGEN D u r i ng th e d esi g n o f Incinerato r 3 T’ s are important Volume o f th e combustio n chambe r - car e ful l y determined Temperature has to be maintained Ox y g e n i n th e form o f ai r i s suppl i e d for ensuring complete combustion When e xces s a i r i s v e r y l a rg e – th e f u rnace temperature will be reduced

10. CLASSIFICATION OF INCINERATOR According to the Purpose of Incineration Domestic- 50kg/ Hr Commercial- 50 – 500 kg/ Hr Municipal – above 500kg/ Hr Multiple Chamber Incinerators are divided into two types Retort Type Inline Type

11. GENERAL CONSTRUCTION DETAILS OF MUNICIPAL INCINERATOR Reception & Storage Charging Hopper and Conveyor Furnace Grates & Stocking

12. Construction Details of Municipal Incinerator

13. Construction Details of Municipal Incinerator

14. Sectional View of Retort Multi Chamber Incinerator

15. PRODUCTS OF INCINERATION Siftings- fine material which fall through the grate opening during drying, ignition & combustion process Residues Clinker & Fly ash Removal of Suspended particulate

16. OPERATION AND MAINTENANCE Burning Rate Draft Auxiliary Fuel Control Equipment Maintenance

17. DISADVANTAGES OF INCINERATION Capital cost is high Skilled operators are required All materials are not incinerable ( Construction & Demolition) Supplementary fuel is required to initiate the process and to maintain the incineration process The installation of air pollution control equipment make the process expensive – located after furnace & before the stack Bottom residue – Harmful Metals

18. PYROLYSIS Therma l process i ng o f w a ste i n complet e absence of oxygen Also ref e rr e d a s the r mal decompositio n or destructive distillation or carbonization Endothermic reaction The three major component resulting from the pyrolysis process A gas steam- depending upon the organic characteristics of material being pyrolized A Liquid Fraction – containing acetic acid, acetone, methanol, and complex oxygenated hydrocarbons. Option to the synthetic fuel oil Char- consisting of almost pure carbon + any inert material originally present in the solid waste

19. PYROLYSIS Normally Pyrolysis is carried out in two range Low temperature Pyrolysis- 500˚C High temperature Pyrolysis- 900 ˚C Three methods – Destrugas System Garrets Flash Pyrolysis Process Process Developed by Energy Research Centre of Bureau of Mines, Pittsburg

20. PYROLYSIS Normally Pyrolysis is carried out in two range Low temperature Pyrolysis- 500˚C High temperature Pyrolysis- 900 ˚C Three methods – Destrugas System Garrets Flash Pyrolysis Process Process Developed by Energy Research Centre of Bureau of Mines, Pittsburg

21. OPERATION PROBLEMS WITH MSW PYROLYSIS SYSTEM Pyrolysis is still widely used for the production of charcoal from wood, and activated carbon, methanol & other chemicals Pyrolysis of solid waste has not been successful The principal causes of failure- complexity of the system & lack of appreciation by the system designers

22. GASIFICATION SYSTEM Simpler and most cost effective technology The principal difference between the two system is that pyrolysis systems use an external source of heat to drive the endothermic pyrolysis reactions in an oxygen free environment, where as gasification systems are self- sustaining and use air or oxygen for the partial combustion of solid was te

23. Gasification system-details Involves partial combustion of carbonaceous fuel to generate combustible fuel gas Rich in CO,H, and CH4 Used in Internal Combustion engine,Boiler Gasifier Types Vertical Fixed Bed Horizontal Fixed Bed Fluidized Bed Multiple Hearth Rotary Kiln