I hereby declare that I am responsible for the work submitted in this project, that the original work is mine except as specified in the references and acknowledgments, and that the original work contained herein was not performed or performed by anyone other than -specified sources or persons. . The production of hydrogen from the gasification of biomass has become an alternative energy source replacing the combustion of fossil fuels. However, steam gasification of biomass produces not only useful products, but also undesirable products such as tar, which will affect the efficiency of the gasification plant.
This research project focuses on the development of a kinetic reaction model for tar cracking based on steam gasification using simulation software such as MATLAB and to calculate the reaction constant of tar cracking via optimization approach. First of all, I would like to express my greatest gratitude to my last year's project supervisor, Dr. Abrar Inayat, for his guidance, supervision, encouragement and support throughout my final year project period. Dr. Abrar has provided much knowledge on how tar cracking is developed, as well as his teaching on using MATLAB to develop a kinetic model for my final year project.
Without his guidance and assistance, this project may not have been completed smoothly or on time. In addition, I would also like to thank some of my post-graduate friends who are currently pursuing their master's or doctoral studies. Universiti Teknologi PETRONAS (UTP) Program for their guidance, advice and endless support provided to me during my final year of the UTP undergraduate program.
Last but not the least, I would also like to thank my parents, siblings, relatives and friends who accompanied and supported me all the way through my study period after I finished as an undergraduate student in UTP.
INTRODUCTION
BACKGROUND OF STUDY
5 (SO2) which are harmful to the environment as nitrogen and sulfur are present in some fossil fuels. With the use of battery energy storage, the storage capacity is limited and will only be a temporary power supply solution, but not as a long-term solution. With the help of the fuel cell, when hydrogen is converted into useful electricity, the byproduct of the process is an environmentally friendly component, water.
Hydrogen is mainly produced by burning fossil fuels such as natural gas steam reforming. However, this process is non-renewable and non-environmentally friendly, as the by-product of this process is a pollution of the environment. Many scientists believe that the development of renewable energy can effectively eliminate the current problem of global warming.
In recent years, the use of bioenergy is increasing as a new source of renewable energy and has the potential to replace energy production from fossil fuels. One of the potential sources of renewable energy to generate power comes from biomass (Tanksale et al., 2010).
PROBLEM STATEMENT
7 Figure 1: Summary of tar elimination methodology for producing useful products. Adapted from "Improving the Modeling of Kinetics of Catalytic Tar Elimination" by Corella, .
OBJECTIVE
SCOPE OF STUDY
LITERATURE REVIEW
Houben conducted another experiment examining the effect of reactor temperature on gas production. 11 From the results obtained by Houben, we can say that the amount of gas composition can be affected by the residence time in the reactor. The composition of carbon monoxide and hydrogen shows an increase in composition as the residence time increases, while the composition of carbon dioxide and methane decreases.
Morf et al (2002) conducted an experiment to investigate the homogeneous conversion of tar without external oxidant supply in a tubular flow reactor operating at temperatures ranging from 500 to 1000oC with residence times below 0.2 seconds. From the results obtained by Morf et al under the specified reaction conditions, the increase in the concentration of carbon monoxide, hydrogen and methane in the pyrolysis is shown when the temperature of the secondary homogeneous reaction of tar exceeds more than 650oC. Evans and Milne (1987) have characterized types of tar compounds based on temperature range.
The primary products of tar cracking found in the reactor range between 400-700oC with the presence of oxygenated compounds. Aromatics that are classified as tertiary products are in the reaction range of 850-1000 OC and can be further divided into classes of "tertiary alkyl products". According to Devi et al (2003), the high production of hydrogen during steam gasification can be attributed to the following chemical equations that represent the tar reforming reaction which contributes to the increase in the content of hydrogen and CO gases.
12 The presence of carbon dioxide in the atmosphere will make its use as a gasification medium promising. Minkova et al (2000) state that a mixture of steam-CO2 gives the highest degree of carbonation in a rotary biomass gasification reactor. CO2 gasification in the presence of catalyst converts tar and decreases the amount of methane and C2 fraction, as well as increases the hydrogen and carbon monoxide yield.
A significant decrease in carbon dioxide content was observed at a CO2/biomass ratio of 1:16, indicating that carbon dioxide is converted to other products. The main equation of the chemical reaction with carbon dioxide as the gasification medium representing the reaction of drt reforming tar is as follows. 13 The overall rate of tar cracking into smaller hydrocarbons is given by the sum of the rates of all basic individual reactions involved in the tar cracking network.
METHODOLOGY
RESEARCH METHOLODOGY
PROJECT FLOW CHART FOR FINAL YEAR PROJECT
GANTT CHART
RESULTS AND DISCUSSION
Benzene and toluene undergo steam reforming together with a homogeneous water-gas shift reaction as shown in reaction equation (1) to (5). There are many possibilities for a rate equation that can represent the kinetic behavior of reaction (1) to (5). 21 The total volumetric rate of each component can be determined according to the rules of chemical reaction engineering.
DEVELOPMENT OF MATLAB CODING
Function files
E3 %WGS forward reaction(activation energy)(E/R) %A4 %Toluene thermal for CO/H2 (pre-exp. factor) %E4 %Toluene thermal for CO/H2(E/R).
MATLAB Main File (M-File) for optimization calculation
OPTIMIZATION RESULTS
REACTION RATE CALCULATION
Volumetric rate of products
This may be due to the thermal cracking efficiency of tar where hydrogen production can increase with increasing temperature. Therefore, the increase in temperature favors the reaction to occur in the production of hydrogen, carbon monoxide and carbon dioxide. This also explains the increase in yield and hydrogen production ratio as shown in Figure 9 and Figure 10 respectively.
Yield of products
Flammability Limit
Due to the increase in hydrogen content as the temperature increases, the flammability limit area increases as shown in Figure 11.
MODEL VALIDITY
CONCLUSION & RECOMMENDATION
CONCLUSION
RECOMMENDATION
Thermochemical treatment of biomass in a quantity of steam or in a mixture of steam and carbon dioxide.
