A detailed note about the conversion of waste energy into electrical energy.Here is an idea about using our waste by converting it to a useful energy which can produce electric power and lower the power deficiency.

1. Striclty for educational purposes
•
Final project in M.Sc. Course for teachers, in
the framework of the Caesarea –Rothschild
program of the Feinberg Grad School of the
Weizmann inst. of Science.
•
Note that ppt may contain copy-righted
material and as such any use that can violate
such rights will require permission from the
© holders.

2. Waste to Energy
via Syngas (synthetic gas) production
and Fischer –Tropsch biodiesel
Ben Osher
How much diesel can be produced from solid waste in Israel ?

3. Why Use Waste?
• As the amount of fossil fuels available
decreases and the cost of petroleum-
based fuels increases, there is a need for
alternative fuel sources.
• A promising process for green-fuel and
electricity production involves the
formation of SYNGAS which can be
converted to useful fuel and other
organic materials.

4. What is syngas?
the main compounds in syngas are:
* Carbon monoxide : CO
* Hydrogen: H2
Other by-products:
* Carbon dioxide: CO2
* Methane: CH4
Abbreviation of “synthetic gas”.
It can be the end product of thermally processed biomass

5. waste Syngas
GREEN
DIESEL
Gasification Fischer-Tropsch
What can be done with syngas?

6. Waste treatment: OLD vs. reNEWable

7. • How much waste is there to be treated?
• What type of waste is to be treated?
For example does it contain just MSW or does it
include commercial waste, sewage sludge , tyres
etc.?
• What are the characteristics of the waste in terms
of chemical composition, caloric value, particle size,
moisture etc.?
Dealing with waste - Questions to be asked:

8. Municipal Solid Waste
MSW
BIOGENIC NON-BIOGENIC
such as food waste
and yard clippings
such as plastics and metals
http://www.eia.gov/todayinenergy/detail.cfm?id=8010

9. With time the biogenic portion of municipal solid waste decreases;
Because non-biogenic waste has a higher heat content than biogenic material
the average heat content of MSW (per unit mass) as a whole is increasing,
making it a more efficient fuel for producing electricity .
Municipal Solid Waste
http://www.eia.gov/totalenergy/data/monthly/pdf/historical/msw.pdf

10. Israel: waste facts
• 4.9 million ton of MSW is produced each year.
• Average waste/person/day 1.9 (3-5% growth)
• ~20% of MSW is recycled => ~ 1.5 kg/day/person to landfills
• Total fuel consumption for private transportation is
http://www.sviva.gov.il/subjectsEnv/Waste/Policy/Documents/waste_management.pdf
year
l
9
10
35
.
5 

11. Thermal waste treatment
Thermal waste
treatment
Combustion pyrolysis gasification
rapid oxidation of a
feedstock as it
is exposed air .
heat in a boiler
where steam, under
high pressure, is
passed through a
turbine which
powers a generator
Thermal degradation
of waste in the
absence of air to
produce char, oil,
and syngas.
e.g. wood to
charcoal
C
C 0
0
600
300  KPa
C
7000
1400
~ 0
Breakdown of
hydrocarbons into
syngas by controlling
the amount of
oxygen during
burning.

12. Gasification: Main chemical reactions
Within a gasification process the major chemical reactions are those involving
carbon, CO, CO2, water (steam) and methane, as follows:
mol
kJ
H
H
CO
O
H
CH 9
.
205
3 2
2
4 




mol
kJ
H
H
CO
O
H
C 6
.
122
2
2 




First step: steam
mol
kJ
H
O
H
O
H
mol
kJ
H
CO
O
CO
1
.
241
2
1
9
.
401
2
2
2
2










Second step: air / 2
o
Third step:CO formation
mol
kJ
H
CO
CO
C 9
.
164
2
2 



4
2
2 CH
H
C 

Endothermic reactions
Methane needed comes from
Exothermic reactions

13. Fischer-Tropsch Synthesis
It uses Iron- or Cobalt-based catalysts
  O
H
CH
H
CO catalyst
2
2
2
2 



 


2
2
2 H
CO
O
H
CO 


2
2

CO
H
When the H2/CO ratio in the feed gas is lower, it can be adjusted with the
water gas shift reaction to use the component in excess to yield the missing one:
The process involves a series of chemical reactions
that produce a variety of saturated hydrocarbons
Professor Franz Fischer (left)
and Dr Hans Tropsch

14. FT Chemical mechanism:

15. Overall process: waste in - no waste out

16. MSW conversion and synthesis to F-T products with heat recovery
can make beneficial and commercial use of 71%.
Overall process: Hypothetical energy recovery

17. Calculations:
t
l
l
MWh
t
MWh
t
MWh
l
kWh
323
}
011
.
0
/{
5
71
.
0
5
~
;
11


Diesel energy density
Amount of diesel
Av. energy value of MSW
year
t
6
10
1
~ 
year
l
t
l
year
t 8
6
10
23
.
3
323
10
1 



Part of MSW for thermal treatment
in Israel
Amount of diesel produced

18. A ton of MSW with average energy content of ~5
can yield up to: 323 liters of ultra clean Diesel fuel.
t
MWh
FT diesel assumed to be 7.19 $/bbl (~0.16 ‫לליטר‬ ‫)שקל‬
more expensive than transportation fuels derived from
crude oil. Choi & al, 2011
F-T fuels can replace 6% of total fuel consumption in Israel!
Conclusions:

19. Advantages ( if goals are achieved)
• Reduction of municipal and industrial
waste disposal.
• Reduction of CO2 emissions from
incineration.
• Use of renewable low cost feedstocks
• Converting waste into ultra clean-diesel.
• Use of sustainable methods to convert
waste into useful products

20. By treating our wastes we do not only do
good for the environment but also good
business for the local- and global economy.