The document discusses plasma arc technology as an alternative waste treatment method. It begins by outlining the increasing waste generation problem in urban India. Plasma arc technology gasifies waste in an oxygen-starved environment to produce syngas, vitrified slag, and other products. The key components of a plasma gasification system and factors affecting performance are described. Plasma arc technology offers advantages over incineration like lower emissions and more energy efficient operation. While holding potential, the technology also faces limitations like high costs and lack of standards that have hindered wider adoption in India.
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INTRODUCTION
• The increasing industrialization, urbanization and changes in
the pattern of life give rise to generation of increasing
quantities of wastes.
• Increases threats to the environment.
• Every year, about 55 million tonnes of municipal solid waste
(MSW) and 38 billion litres of sewage are generated in the
urban areas of India.
• In addition, large quantities of solid and liquid wastes are
generated by industries.
• Waste generation in India is expected to increase in the future.
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• Waste-to-Energy technologies can solve this problem to some
extent.
• Although mass-burn technologies continue to dominate in
waste-to energy plants, there are some alternative technologies.
• One such technology is Plasma arc technology
• Plasma gasification process is an efficient and environmentally
responsible form of thermal treatment of wastes which occurs in
oxygen starved environment so that waste is gasified, not
incinerated.
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NEED FOR PLASMA ARC TECHNOLOGY
• Solid Waste management (SWM) is an acute and complex
problem in developing economies like India.
• Inadequate budget for waste management
• Various techniques like land filling, incineration and composting
have been used for waste management, but none of them fully
assure the growing need of waste management in major cities.
• Thus there is a great need for plasma gasification.
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COMPONENTS OF PLASMA
GASIFICATION SYSTEM
The main components of the whole plasma gasification
system are as given blow:
1. Waste feeding system
2. Plasma Gasifier
3. Plasma generating devices
4. Waste processing facilities
4. Yields and bi-products of plasma arc technology
6. Syngas cleaning facilities
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WASTE FEEDING SYSTEM
• The feedstock for plasma waste treatment is most often
municipal solid waste, organic waste, or both.
• Also include biomedical waste and hazmat materials.
• Content and consistency of the waste directly impacts
performance of a plasma facility. Pre-sorting and recycling
useful material before gasification provides consistency.
• Too much inorganic material such as metal and construction
waste increases slag production, which in turn decreases syngas
production.
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2.PLASMA GASIFIER
• Gasifier/Reactors can be
constructed with
different materials,
which in turn decide the
life of operation.
• Plasma furnace is a
vertical refractory lined
vessel into which the
contaminated waste
material is introduced
near the top.
Plasma reactor
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2. PLASMA GENERATING DEVICES
• Most thermal plasma is generated by either an electric arc or
by a radio-frequency induction (RFI) discharge.
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Plasma torch
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Types of plasma torches used are
1. DC Plasma Torches
2. RF Plasma Torches
3. AC Plasma Torches
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3.PROCESSING OF WASTES
• Small torches –Argon
• Larger torches – Nitrogen
• Electrodes-copper, tungsten, hafnium, zirconium, along with
various other alloys
• A strong electric current under high voltage passes between the
two electrodes as an electric arc.
• The waste is heated, melted and finally vaporized.
• Complex molecules are separated into individual atoms.
• Result in syngas.
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4.YIELDS OF PLASMAARC TECHNOLOGY
Syngas
• Pure highly calorific synthetic gas consists predominantly of
carbon monoxide (CO) and hydrogen (H2).
Vitrified slag
• The inorganic part of waste stream i.e. glass, soil, sand etc. are
being converted into vitrified slag like glassy material
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HCL/Na2S Solution
• For the removal of HCN, SO2, H2S and residual HCl and HF
from syngas an alkaline scrubber can be used
• This leads to formation of HCl and Na2S solution
5.SYNGAS CLEANING
• Remove pollutants such as sulfur dioxide (SO2), particulate
matter, hydrochloric acid (HCl) and Hydrogen Sulfide (H2S)
vapors from the synthesis gas.
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FACTORS AFFECTING PERFORMANCE OF
PLASMA ARC TECHNOLOGY
• Moisture Content
• Residence time
• Gasifying agent
• Gasifying agent waste ratio
• Reaction temperature
• Equivalence Ratio
• Pressure
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COMPARISON BETWEEN PLASMA GASIFICATION AND
INCINERATION
PLASMA GASIFICATION INCINERATION
Occurs in the absence or near
absence of oxygen, prohibiting
combustion.
Excess air is induced to ensure
complete combustion.
Gases resulting from degradation of
organics are collected and used for
production of various forms of
energy and/or industrial chemicals.
All potential energy converted to heat.
Products of degradation largely
converted to inert (non-hazardous)
glass-like slag of a volume 6% to
15% of the original solids volume.
Combustion results in ash (as much as
30% of original solids volume) that
must often be treated as hazardous
waste
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Emissions substantially lower
than those resulting from
incineration.
Far greater emissions of GHG
and other pollutants than with
thermal gasification systems.
Lower levels of CO, NOx, Tars.
Other pollutants are vitrified in
slag
PM, Tar, SOx , NOx, Dioxin,
Furans, Fly ash, heavy metal
volatilization
Temperature 1500 °C-5000 °C Temperature 850 °C-1200 °
Pressure, atm 1-45 Pressure, atm 1
Stoichiometric ratio <1 Stoichiometric ratio >1
Reducing environment Oxidizing environment
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COMPARISON OF WASTE TO ENERGY
CRITERIA POLLUTANTS
• Based on studies done
by Dipal Parsania, Prof.
Dr. N S Varandani and
Minarva Pandya
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Emissions
(mg/N-M3@7%O2)
Measured USEPA Standards
PM <3.3 20
HCl 2.7 40.6
NOX 162 308
SOX - 85.7
Hg 0.00067 50
Dioxine/furans 0.0067 13
EPA Verification Testing Of Thermal Plasma Process For 10 Tpd
Of Medical Waste
EMISSION TESTING OF PLASMA GASIFICATION
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EXPERIMENTAL STUDY
• A preliminary economic analysis was completed on the five
thermal processes by Dr Gary C Young.
• The processes were mass burn incineration, pyrolysis,
pyrolysis/gasification, conventional gasification and plasma
arc gasification.
• Parameters used in this economic evaluation were capital
investment, plant capacity ,energy production, operation and
maintenance, capital budget, cost of ash disposal, tipping
fee, green tags, production energy, by-product and residue.
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816
685
685
571
544
Plasma arc gasification
Conventional gasification
Pyrolysis/gasification
pyrolysis
Mass burn incineration
Net energy production to grid(kWh/ton MSW)
Net energy
production to
grid(kWh/ton
MSW)
COMPARISON OF VARIOUS WASTE TO ENERGY
PROCESSES
Note-Computations in this table done by Dr.Gary C Young
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CASE STUDY
SACROMENTO, CALIFORNIA
• This case study shows the current domestic barriers in
moving forward with this new Waste to Energy technology.
• The failure of plasma gasification in Sacramento is
representative of two main domestic barriers: a discouraging
lack of precedent and a lack of financial security.
• Internationally, plasma gasification plants are rewarded by
‘recovering’ energy from waste, while in the United States,
plasma gasification is seen in the same unhealthy vein as
incineration, which leads to a lack of subsidies and public
disapproval.
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MIHAMAAND MIKATA,UTASHINAI CITY, JAPAN
• A 165 ton per day plant in Utashinai City, and a 28 ton per day
plant in the twin cities of Mihama and Mikata
• Was one of the first plasma gasification facilities worldwide
• It now processes a mixture of auto shredder residue and
municipal solid waste.
• The primary concerns at Ecovalley were an improperly sized
gasifier, a low quality refractor, and excessive particulate
carryover which led to cease its operation for short time
• The new gasifiers have all taken into account these issues and
plants without these problems
• It is successful and still operate to this day
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• The economics of plasma gasification facility is very
appropriate via multiple income streams although it is
complex.
• Tipping fees is removed
• Electricity is produced as output.
• Liquid fuels, hydrogen and effective syngas.
• Slag and sulfur for sale.
• Cost estimation of a typical plant is given as a feedstock of
3000 tons of MSW per day with cost over 400 million $
producing about 120 MW of electricity.
ECONOMIC ANALYSIS
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ADVANTAGES
• Syngas used to generate" green electricity“.
• Slag can be used for road aggregate and building materials.
• Does not produce hazardous bottom ash and fly ash
• Very little maintenance and unlike traditional power plants.
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ADVANTAGES (Cont.)
• Efficient in smaller scale systems
• Can provide a high degree of flexibility over the longer term
• Does not make difference among input wastes
• Reduces emissions far below conventional coal plants
• Limited space requirement
• Lower carbon footprint
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LIMITATIONS
• The lack of standards by national and international
organization
• Initial cost and return of investigation
• Skepticism on environment effects
• Confusion between plasma gasification and incineration
• Complex process control & highly skilled professionals are
required
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APPLICATIONS
• Space Programs
• Remediation of Radioactive Waste
• Animal Carcass and Animal Waste, Agricultural Waste, Paper
and Pulp Industry Waste
• Soil in Situ (borehole) Vitrification
• Municipal Solid Waste
• Automobile Tyres, Coal, Sludge Glass waste and Ceramic waste,
Hazardous fly ash destruction
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SCOPE OF PLASMAARC TECHNOLOGY
IN INDIA
• Every day, urban India generates 188,500 tonnes of MSW - 68.8
million tonnes per year.
• More than 80% reaches open dumpsites where it causes
damaging public health, deteriorating the environment, and
causes climate change.
• This situation can be avoided by introduction of plasma
gasification techniques.
• India's only plasma technology plant in Pune, recently came
under scrutiny due to its failure to run at capacity.
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SCOPE OF PLASMAARC TECHNOLOGY
IN INDIA (cont..)
• Studying the reasons for this failure, which are currently
unknown, could provide a better picture .
The suggested roadmap include;
1. Establish standard organization
2. Certifying the plasma gasifying plants
3. Certifying the vitrified materials
4. Government intervention
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CONCLUSION
• Gasification could now be proposed as a viable alternative
solution for waste treatment with energy recovery.
• It is viable and sustainable.
• Independently-verified emissions tests indicate that gasification is
able to meet existing emissions limits and can have a great effect
on the reduction of landfill disposal option.
• Government should take the required initiatives to develop this
technology for alternative power generation to address power
shortages and reduce the use of fossils.
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REFERENCES
[1] NallapaneniManojKumar.(2018).“Petrochemical Waste Treatment using Plasma
Technology.”International Journal of Engineering Computational Research and
Technology.
[2]Carpinlioglu, MeldaOzdinc, and AytacSanlisoy. (2018). "Performance assessment of
plasma gasification for waste to energy conversion: A methodology for thermodynamic
analysis." International Journal of Hydrogen Energy 43.25: 11493-11504.
[3] YAZICIOĞLU, Özge, and T. Yaşar KATIRCIOĞLU.(2017)."Applications of Plasma
Technology in Energy Sector."Yazıcıoğlu&Katırcıoğlu / Kirklareli University Journal of
Engineering and Science. 18-44.
[4] Abushgair, K., Ahmad, H., &Karkar, F. (2016). Waste to Energy Technologies-Further
Look into Plasma Gasification Implementation in Al-Ekaider Landfill, Jordan.
International Journal of Applied Environmental Sciences, 11(6), 1415-1425.
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