POTENTIAL OF GARDEN WASTE AS RENEWABLE ENERGI USING CATALYTIC PYROLYSIS, CASE STUDY BANDUNG CITY
The increasing number of city parks has caused the amount of waste generation from the urban sector to become uncontrollable. On the other hand, the scarcity of energy sourced from fossil energy has had an impact on people’s social lives. Several policies have been pursued in order to overcome th...
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| Format: | Dissertations |
| Language: | Indonesia |
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| Online Access: | https://digilib.itb.ac.id/gdl/view/80029 |
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| Institution: | Institut Teknologi Bandung |
| Language: | Indonesia |
| Summary: | The increasing number of city parks has caused the amount of waste generation
from the urban sector to become uncontrollable. On the other hand, the scarcity of
energy sourced from fossil energy has had an impact on people’s social lives.
Several policies have been pursued in order to overcome the energy crisis including
finding new renewable energy sources that can be used sustainably. Garden waste
has the potential to be developed as a renewable energy source. This research
examines aspects of novelty in scientific development in the field of urban park
waste management technology which includes aspects of waste generation,
technology use, potential energy and electrical power and energy contribution in
achieving the New Renewable Energy target. The research was conducted in two
stages, namely field survey and laboratory scale. The field survey consisted of
observations of waste generation, composition and characteristics of city park waste
as a basis for laboratory-scale research. The types of waste consisted of leaf waste
and plastic waste from ten thematic parks in Bandung City. The laboratory-scale
research is an application of catalytic pyrolysis technology that aims to convert
garden waste into energy products. The process takes place under batch conditions
using a fixed bed reactor at a temperature variation of 100-500oC, sample weight of
50-200 grams, process using catalyst and without catalyst. Analysis of the pyrolysis
process consists of yield values and product characteristics, mass balance and
conversion, energy balance and efficiency, pyrolysis process kinetics, electrical
potential and energy contribution in achieving EBT targets.
Analysis of waste generation, composition and characterization aims to assess the
potential for using garden waste as renewable energy by analyzing the amount of
generation based on parks, seasons, number of trees and park area for leaf waste,
and the amount of generation based on parks, seasons, visiting times consisting of
the beginning of the week and weekends as well as the number of visitors for visitor
waste. Waste characteristics are analyzed using proximate and ultimate methods,
composition analysis, and elemental analysis using XRF (X-Ray Fluorescence).
The research results show that the type of park, number of trees, season, number of
visitors, significantly influence the generation of Bandung City park waste.
The composition of park waste consists of 91.18% leaf waste, 8.6% visitor waste
and 0.22% other types of waste. Average leaf waste generation is 44.65 ± 2.20 kg/park/day with a number of trees 10-270 and visitor waste generation is 4.8
kg/park/day or 0.13 kg/person/day with an average number of visitors -average 35
people. The composition of visitor waste is dominated by plastic bag waste,
reaching 38%. Analysis of the chemical components of leaf waste consists of
21.87% cellulose, 10.17% hemicellulose and 10.20% lignin, 0.30% sulfur content,
40.45% carbon and 83.08% volatile content. Elemental analysis using XRF resulted
in the largest component in leaf waste being the element Ca (calcium) 51.6% and
the calorific value of leaf waste was 3612 kcal/kg.
The pyrolysis process produces three types of energy products consisting of
charcoal, bio-oil and gas. The variables analyzed consist of: the influence of
temperature, biomass weight and catalyst on the yield of pyrolysis products. The
product is characterized by analyzing the heating value, FTIR analysis, SEM
analysis, GC-MS, XRF, ultimate analysis and proximate analysis. Based on the
temperature, the highest charcoal yield was 92 - 96%, with a temperature of 100 -
200 oC in the process without a catalyst, the highest bio-oil yield was 13% - 22%
at a temperature of 200-300 oC. Meanwhile, 20 – 83% gas was obtained at a
temperature of 100-500 oC in the catalyzed process with a sample weight of 50-200
grams. The calorific value of leaf waste increased from 3612 kcal/kg for waste
without pyrolysis to 8876.5 kcal/kg for bio-oil and charcoal was obtained at 6000.8
kcal/kg in the catalysis process. FTIR analysis showed that the OH groups and
aliphatic CH groups were related to phenol and carboxylic acid. SEM analysis
shows that leaf waste charcoal has large pores. GC-MS analysis of bio-oil from leaf
waste was dominated by Phenol (C6H6O) 9.0%, Cresol, (C7H8O) 9.4%, 11,2,3-
Trimethylbenzene (C9H12) 9.9%, 1- methyl-2-cyclopropen-1 (C9H18) 9.5%,
exadecanoic acid (C16H32O2) 10.7%, while plastic waste is dominated by furan
compounds 8.8%, Cyclohexane 3.9%, 1,3-trimethylcyclopentylamine 5, 0%, nhexanoy 4% 4'-dimethoxyphenyl 4.7%, 2-p-Nitrophenyl-oxadiazol-1 3.5%. XRF
analysis of leaf waste contains the mineral elements Na, Mg, Al, Si, P, S, Cl, K, Ca,
Ti, Mn, Fe, Co, Zn, Rb, Sr and Pb. Plastic waste samples consist of Al, Si, P, S, Cl,
K, Ca, Ti, Fe, Cu, Zn, Zr, and Pb, mineral analysis does not show elements that are
harmful to the environment. Leaf waste charcoal has a low sulfur content of 4.0%,
indicating that garden waste has the potential to be developed into a source of
renewable energy.
To analyze the performance of the pyrolysis process, the mass and energy balance
is studied based on the input mass and energy as well as the output mass and energy
during the pyrolysis process, then the kinetic parameters are determined which
consist of the reaction rate constant, activation energy and the kinetic equation
obtained from the results of the graph plot between temperature (1/T) with the
reaction constant (k). Conversion is determined based on the number of solid
samples that are converted into products, while energy efficiency is the ratio of the
amount of output energy to input energy. Maximum conversion was obtained on
the activation catalyst with 25 grams of solid sample remaining, 15 grams of liquid
and 160 grams of gas, 87% conversion at a sample weight of 200 grams,
temperature 500oC. The addition of plastic was able to increase the liquid product to a maximum of 55 grams in the catalyst activation process at a temperature of
400oC with a sample weight of 200 grams. Maximum product energy was obtained
from garden waste in the form of charcoal, bio-oil and gas, 7115 kJ/gram, at a
temperature of 100 – 500oC, weighing 50 – 200 grams. The energy required for the
process is 5940 kJ with a process efficiency of 79.37%. Kinetic analysis shows that
the process without a catalyst produces an activation energy of 1786 – 2136
kJ/gram, the catalyzed process 1168 – 1508 kJ/gram, and the activation catalyst
1138 – 1453 kJ/gram, which shows the catalyst lowers the activation energy.
Determining the electricity potential and energy contribution in achieving the EBT
target aims to analyze the amount of electrical power produced from green open
spaces as a source of municipal waste-powered generation. Electrical power
potential is analyzed based on the type of park, the amount generated by each park,
the pyrolysis process and without pyrolysis. The results obtained show the
electricity potential of Bandung City's garden waste with an average amount of leaf
waste generation of 44.65 kg/day/garden producing 0.193 MW of power for waste
without pyrolysis with a potential contribution to the EBT target of 0.000033 MW.
Meanwhile, the electricity potential with the catalytic pyrolysis process produces
0.33 MW of power with a potential contribution to the EBT target of 0.000057 MW.
Visitor waste with generation of 4.81 kg/day/park produces 0.037 MW of power
for waste without pyrolysis with a potential contribution to the EBT target of
0.0000064 MW. Meanwhile, the electricity potential with the catalytic pyrolysis
process produces 0.044 MW of power with a potential contribution to the EBT
target of 0.0000076 MW. The pyrolysis process increases the energy potential of
city park waste and reduces waste from the source, so it has the potential to be
developed in sustainable management of city park waste. |
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