TRANSFORMING WASTE INTO ENERGY :THE ROLE OF INCINERATION IN ELECTRICITY GENERATION FROM MUNICIPAL SOLID WASTE

TRANSFORMING WASTE INTO ENERGY :THE ROLE OF INCINERATION IN ELECTRICITY GENERATION FROM MUNICIPAL SOLID WASTE

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
1035.5

11. Thermal waste treatment
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
CC
00
600300
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
HHCOOHCH 9.2053
224 
mol
kJ
HHCOOHC 6.122
22 
First step: steam
mol
kJ
HOHOH
mol
kJ
HCOOCO
1.241
2
1
9.401
22
22


Second step: air /
2
o
Third step:CO formation
mol
kJ
HCOCOC 9.1642
2 
42
2 CHHC 
Endothermic reactions
Methane needed comes from
Exothermic reactions

13. Fischer-Tropsch Synthesis
It uses Iron- or Cobalt-based catalysts
 OHCHHCO
catalyst
2222 
222 HCOOHCO 
2
2

CO
H
When the H
2/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/{571.0
5~
;11

Diesel energy density
Amount of diesel
Av. energy value of MSW
year
t
6
101~
year
l
t
l
year
t
86
1023.3323101 
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 רטילל לקש)
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.