Doctor of Philosophy (Ph.D.)

Permanent URI for this collectionhttp://192.248.9.226/handle/123/12728

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item: Thesis-Abstract
Risk-based chemical process route selection considering inherent environmental friendliness
(2024) Rathnasekara, PK; Gunasekera YM
Chemical process route selection is one of the key decisions taken during the preliminary design stage of process plant development. A chemical process route is defined as the raw material(s) and the sequence of reaction step(s) that convert them to the desired product. In the past, the 'best' process route was selected solely considering economic factors. However, with the disastrous chemical plant accidents experienced in the past, attention has been drawn to select process routes considering other factors such as inherent environmental friendliness. Therefore, methodologies that assess chemical process routes considering environmental aspects are needed for the development of inherently environmentally friendly chemical process plants. The work presented in this thesis proposes a risk-based methodology to assess and rank chemical process routes considering inherent environmental friendliness using the data available during preliminary design stage of chemical process plant design and development. The environmental impacts that could occur due to chemical plant accidents such as accidental chemical releases, fires and explosions are considered when developing the methodology. In the proposed methodology, the chemical process routes are assessed in three approaches. They are fires and explosions, accidental chemical releases and all these three accidents in combination. Therefore, three risk indices are proposed namely, the Inherent Environmental Risk Index for Fires and Explosions (F&E-IERI), the Inherent Environmental Risk Index for accidental Chemical Releases (Chem-IERI), and the Inherent Environment Risk Index (Chem F&E-IERI). A lower risk index of a process route indicates a lower environmental risk and, thus the most inherently environmentally friendly route among the alternate process routes. The proposed methodology is applied in four potential process routes in acetone production. The results obtained show that the process route that has the lowest environmental risk due to fires and explosions in the chemical plant is the p-diisopropyl benzene oxidation process. The dehydrogenation of 2-propanol process route shows the lowest environmental risk due to accidental chemical release. The chemical route that has the lowest environmental risk due to all three major chemical plant accidents, fires, explosions, and chemical releases is the dehydrogenation of 2-propanol process. Keywords: Environmental risk assessment, chemical process route selection, accidental chemical releases, fires and explosions, inherent safety
item: Thesis-Full-text
Decolourization of textile dyes and textile industry effluent in a fixed bed biofilm reactor using native microorganisms
(2021) Madhushika, HG; Gunawardena, SHP; Ariyadasa, TU
Textile and apparel industry produces huge quantities of wastewater with unfixed dyes, which generate colour and toxicity in discharged water, creating environmental pollution. Physical and chemical effluent decolourization techniques are widely used at present to remove colour in effluents in textile industries, however, they have several drawbacks and therefore not productive. Compared to physical and chemical methods, biological treatments have gained much attention globally as environmental-friendly and cost-effective techniques to decolourize textile industry effluent. Hence, in this work, decolourization potential of textile dyes by microbial strains, which were isolated from local-environment, and their applicability in industrial wastewater decolourization were investigated. Five bacterial strains, with dye decolourizing potential were isolated from an effluent treatment facility of a local textile industry and identified using 16S rRNA gene sequencing analysis. Ability of these strains to decolourize selected textile dyes as individual strains and in a bacterial consortium was investigated using free bacterial cells cultured in 250 ml Erlenmeyer flasks containing 100 ml of decolourization media. Out of the isolated bacteria, Proteus mirabilis showed the highest capability to decolourize all dyes and was able to decolourize 50 ppm dye solutions of Yellow EXF, Red EXF, Blue EXF, Black WNN and Rhodamine under static conditions at 35 °C. Colour removal of 96, 94, 83, 95 and 30% respectively was observed after 72 h of treatment when decolourization media was inoculated with 2% (v/v) of bacterial culture. The developed bacterial consortium composed of Proteus mirabilis, Morganella morganii and Enterobacter cloacae, decolourized more than 90% of all four reactive dyes and 36% of Rhodamine dye after 72 h of incubation. Furthermore, the developed bacterial consortium was able to decolourize more than 83% of the synthetic dye mixture and 60% of the textile industry effluent, respectively after 46 h and 138 h of incubation at 35 oC temperature under static condition. Effects of physico-chemical parameters (pH, temperature, concentration of dye, agitation and sources of carbon) for biological decolourization of dyes were studied in batch cultures with free cells. It was observed that dye decolourization was more effective under oxygen-limited, static conditions than shaking conditions and the maximum decolourization of dyes was observed at 40 oC and pH 7-8 in the media containing yeast extract as the carbon source. Dye decolourization was further investigated in a fixed bed biofilm reactor where the biofilm was composed with the developed bacterial consortium. Decolourization of the synthetic dye mixture was done with three different concentrations of yeast extract in the feed and more than 90% decolourization of the synthetic dye mixture was observed when the concentration was 2 and 1 g/l in batch operation of the reactor. However, even when the concentration was reduced to 0.25 g/l, 75% decolourization of synthetic dye mixture was achieved in both batch and continuous operation of the reactor. Results showed that dye decolourization was more effective with attached cells (bacterial consortium) in the reactor than with free cells (used in flasks). Stability of the dense microbial communities in biofilms and their ability to survive and degrade dyes at extreme conditions could be the reason for observed high colour removals in the decolourization studies conducted in the reactor. Structural changes occurred in dyes due to biological treatments were studied using ultraviolet-visible spectral and high-performance liquid chromatography analyses. Metabolites formed due to biological degradation were analyzed using gas chromatography-mass spectrophotometry and found to be non-toxic and benign. A maximum of 45% colour removal was observed when the diluted textile effluent was treated in the fixed bed biofilm reactor operated in continuous mode whereas 70% colour removal was achieved in 48 h with undiluted textile wastewater treated in batch mode. This shows the ability of the developed bacterial consortium to endure in highly complex and toxic environment in the fixed bed biofilm reactor and the potential application in textile industry wastewater treatment.
item: Thesis-Full-text
Heat and mass transfer analysis in a spouted bed dryer coupled with a cyclone for pepper drying
(2020) Jayatunga GK; Amarasinghe BMWPK
This thesis outlines the analysis of heat and mass transfer process of drying of black_pepper in a spouted bed coupled with a cyclone separator. Black pepper is a widely used spice and is well-known for its pungency and aroma. Experiments conducted with wetted black pepper reveals that conventional spouted bed has the higher drying rate, higher moisture diffusivity, lower drying time and lower activation energy compared to those of spouted_beds equipped with porous_draft tube and non-porous draft tube. Therefore, the conventional spouted bed was used to conduct the experiments to achieve the objectives of the study since it was identified as the optimum configuration of the spouted bed. Spouting behaviour of raw black pepper was studied in the conventional spouted bed. The minimum spouting velocities of particular bed heights at ambient temperature were determined. Minimum spouting velocity of raw black pepper in the conventional spouted_bed versus static bed height was correlated to a power form of function and the exponent of static bed height was 0.67. The effect of operational conditions; drying air temperature, air velocity and static bed height on drying kinetics of raw black pepper was analysed. The higher values of moisture removal rates were achieved when the dryer was operated with moderately high air temperatures, high air flow rates and shallow beds. Drying kinetic data of raw black pepper in the conventional spouted bed shows only falling rate periods. Effective moisture diffusivity values increased with increasing drying air temperature. The highest effective moisture diffusivity of 2.03×10-10 m2/s was obtained at air temperature of 75 ᵒC. Activation energy for drying of raw black pepper in conventional spouted bed was 38.59 kJ/kmol. Specific energy consumption was calculated and the specific energy consumption values increased with increasing air velocity and decreased gradually with increasing the static bed height. Drying_kinetic data obtained from experiments were fitted to five thin_layer drying models. Results show that the Logarithmic model gives the best fit. In addition, four models were developed for black pepper drying in the conventional spouted bed by correlating drying constants and coefficients of Logarithmic model to stagnant bed height at specified temperatures; 45 ᵒC, 55 ᵒC, 65 ᵒC, and 75 ᵒC. Developed models can be used to estimate the drying time of black pepper in the conventional spouted bed dryer for given moisture reduction in the ranges of 0.14-0.22 m stagnant bed heights and in 2.37 m/s air velocity at specified temperatures. Essential_oil was extracted using hydro distillation from black pepper dried at five different drying conditions. The analysis of components by Gas Chromatography Mass Spectrometry technique shows that the black pepper essential oil comprised mainly monoterpenes and sesquiterpenes. Analysis of variance was conducted and the results show that variation of sesquiterpenes concentration in black_pepper essential oil was significant while variations of monoterpenes, oxygenated terpenes and caryophyllene concentration were non-significant in black pepper essential oil with drying air temperature. In addition, the variation of essential oil yield is statistically significant with drying air temperatures. 65 ᵒC drying air temperature provides consistent quality essential oil with high percentage of caryophyllene and higher oil yield. Heat transfer coefficients for black_pepper drying in the conventional spouted dryer were estimated for different drying conditions of unsteady state drying of black pepper dried from initial moisture content to final moisture content of 15% dry basis. Heat transfer coefficient varied from 35-68 W/m2K for the conditions under the investigation. Dimensional analysis iii was carried out and important dimensionless numbers were identified. A correlation was developed for heat_transfer process as a function of dimensionless groups namely Reynolds number, Nusselt_number, Gukhman_number and static_bed height to particle_diameter with 0.791 of coefficient of determination. Heat transfer coefficients predicted from the developed correlation show a good agreement with the experimentally determined heat transfer coefficients.
item: Thesis-Full-text
Preparation and characterization of natural rubber :montmorillonite clay nanocomposites and their vulcanizates
(2020) Perera SGJ; Egodage SM; Walpalage S
Rubber-clay nanocomposites at low nanoclay loadings are generally prepared using mechanical mixing method as similar to mixing of conventional fillers with rubber. However, the resultant properties prepared with mixing method were reported as not high as expected and the main challenge was the retaining of exfoliated clay structures in the final product after vulcanization. This study focuses on the development of nanocomposites with superior properties from Natural rubber (NR) and Montmorillonite clay (MMT), through development of suitable clay structures, by incorporating of nanoclay into rubber at the latex stage. Twelve series of nanocomposites were prepared to study the effect of processing method (acid co-coagulation named ACC method and acid free co-coagulation named AFCC method using latex, and mechanical mixing method with pale crepe); gelling agents (sodium silicofluoride-G1, cetyl trimethyl ammonium bromide (CTAB)-G2 and combination of CTAB and sodium dodycyl sulphate (SDS)-G3); type of natural rubber latex (field NRL and centrifuged NRL); modifications of MMT and NRL. MMT was organically modified with a cationic surfactant of CTAB to enhance interactions with NR. The modified MMT (OMMT) was further treated with bis(triethoxysilylpropyl) tetrasulfide to facilitate separation of clay layers in the clay stacks, and the treated clay was designated as OMMT-S. The NRL was grafted with succinimide to enhance the compatibility with OMMT-S. The incorporation of OMMT-S into Succinimide grafted NRL was the novelty of the study. These nanocomposites prepared were compounded with the curing and other compounding ingredients to prepare nanocomposite vulcanizates. The clay dispersions, nanocomposites, nanocomposite compounds were characterized by XRD, SEM, FTIR, TGA and the mechanical and thermal properties of the nanocomposite vulcanizates were determined as per the international standards. Tensile strength, elongation at break, mod 300% and hardness of the nanocomposite vulcanizates prepared using AFCC and ACC methods initially increased and then decreased with the increase of MMT loading while tear strength remained unchanged. The nanocomposite vulcanizates prepared using AFCC method showed higher mechanical properties compared to the nanocomposite vulcanizates prepared using ACC method. However, AFCC method exhibited slow drying characteristics. The optimum MMT loadings for nanocomposites prepared using AFCC method and ACC method were recorded at 8 phr and 12 phr, respectively, due to formation of aggregated clay structures at higher loadings, as evident by SEM images. Addition of a gelling agent successfully solved the slow drying problem associated with the AFCC method, however, G1 and G2 gelling agents exhibited significant changes to the properties of the vulcanizates. G3 gelling agent functioned effectively by facilitating quick gel formation, and by exhibiting better mechanical properties of the nanocomposite vulcanizates. Replacement of MMT by OMMT in nanocomposite vulcanizates prepared using AFCC method without a gelling agent showed enhanced mechanical properties at a lower loading of 2 phr. The mechanical properties were further enhanced with the addition of the G3 gelling agent to the nanocomposites with OMMT and is associated with greater interactions between OMMT and NR. The optimum loading was recorded at 5 phr. Replacement of OMMT by OMMT-S in nanocomposite vulcanizate prepared with G3 gelling agent exhibited greater tensile strength and elongation at break at 2 phr loading, and greater mod 300%, tear strength and hardness at 5 phr. XRD analysis and SEM images of nanocomposite vulcanizates revealed that the addition of OMMT-S promotes existences of separated clay layers and fine morphology in the vulcanizates. The nanocomposite vulcanizates prepared using mechanical mixing method incorporating OMMT and OMMT-S into pale crepe gave comparatively lower mechanical properties due to presence of clay aggregates. vi The novel nanocomposite vulcanizates prepared with grafted NRL and OMMT-S with the G3 gelling agent showed overall remarkable mechanical properties at 5 phr. The X-ray diffractograms of the nanocomposite vulcanizates showed exfoliated clay structures and fine morphology. The remarkable properties obtained due to fine morphology developed through exfoliated clay structures as a result of rubber filler interactions are tensile strength of 41 MPa, mod 300% of 6 MPa, elongation at break of 620%, tear strength of 49 N/mm, hardness of 55 IRHD, and abrasion loss of 190 mm3.
item: Thesis-Full-text
Development of a solid-gas coupled model for thermally thick biomass combustion in packed beds
(2020) Perera KUC; Narayana M
The aim of this research is to model the moving grate combustion process by Computational Fluid Dynamics (CFD) method by OpenFOAM software. Kinetic data for heterogeneous reactions, specific to local fuel types is essential. Therefore, pyrolysis kinetics of Rubber and Gliricidia was evaluated by two methods; the sequential approach for Kissinger method and Miura and Maki approach for Ditributed Activation Energy Model (DAEM). The activation energy values obtained by the sequential spproach for Kissinger method are 107.9 kJmol-1 for Gliricidia and 83.44 kJmol-1 for Rubber wood. Obtained activation energy by Miura and Maki approach for DAEM, varies between 190.57 kJmol-1 and 230.58 kJmol-1 for Gliricidia and between 111.52 kJmol-1 and 179.07 kJmol-1 for Rubber wood. A CFD model was developed which describes the wood combustion in fixed grate type packed bed furnaces. Linear rate of mass loss observed in batch type simulations can be used to describe the steady state burning characteristics of a continuously operated furnace which has a feeding rate equal to burning rate. This mass loss rate was used to evaluate Equivalence Ratio (ER) variation for different particle sizes of wood. A sensitivity analysis was conducted to find the effect of moisture content and particle size on ER. It was found that moisture content of wood has more significant effect on ER than the particle size. The optimum equivalence ratio was studied based on the maximum outlet gas temperature with minimum CO fraction for different particle sizes of wood. The optimum ER values obtained were 0.28 for 25 mm sized particles, 0.13 for 38 mm sized particles and 0.18 for 63 mm sized particles. The model was elaborated to simulate wood combustion in moving grate type furnaces. This heterogeneous model developed within Eulerian framework, includes the grate movement through boundary conditions, which can solve both bed and free board region simultaneously.
item: Thesis-Full-text
The Importance of fluidization parameters for the production of quality black tea at higher efficiencies
Kandasamy, R; Amarasinghe, ADUS; Botheju, WS
Orthodox broken type teas, currently producing in tea factories in Sri Lanka, have on average smaller size particles than that of tea produced a decade ago. However most of the tea factories still use the conventional fluid bed dryers and hence they are experiencing difficulties in achieving fluidization with required co-existence of continuous phase and bubble phase. In the present study, fluidization behavior of Orthodox broken type tea was examined in a pilot-scale fluid bed dryer. Six different bedplate configurations were evaluated against the conventional bedplate having perforations of 36 mm  0.5 mm with 3.4 % opening area. The bedplate of 36 mm  0.6 mm with 5 % opening area gave the best performance. A stable fluidized tea-bed with co-existence of continuous phase and bubble phase was achieved without stagnation and entrainment at higher loadings of 44.5 – 50.5 kg/m2 than the conventional loading of 38.5 kg/m2. Further, the fluctuations were found to be minimized for a wide range of fluidizing velocities of 1.3 - 1.9 m/s. A new mathematical model was developed to predict the minimum fluidization velocity by correlating dimensionless Archimedes number, Reynolds number and moisture ratio. The variations in particle size and particle density due to shrinkage during the drying process were incorporated in the new model. The predicted fluidization velocity was found to be in good agreement with the experimental data and the difference was below 10 % for majority of the cases. An empirical model relating the dimensionless moisture ratio to an easily measurable parameter, tea-bed temperature, was also proposed and validated. Drying characteristics of Orthodox broken type tea and the quality variations with the fluidization parameters were also examined using a laboratory-scale fluid bed dryer. Page model was found to give better predictions than the other thin-layer drying models. Free moisture was found to be present above moisture contents of 60 % (w/w, dry basis) and the effective diffusivity was found to be 2.52 x 10-11 m2/s. During the final stage of drying, effective diffusivity was found to vary between 2.660 x 10-11 m2/s and 2.782 x 10-11 m2/s. Quality variations were examined by the method of chemical analysis and organoleptic analysis. The results indicated that better quality tea could be achieved with higher loadings than conventional loading of 38.5 kg/m2 and lower hot air temperatures than the conventional temperature of 124 °C. However, the drying time was found to increase by 2233 % for higher loadings and by 12 – 77 % for lower hot air temperatures.
item: Thesis-Full-text
Performance of natural dye sensitized solar cells for low power applications
Attanayake, CIF; Premachandra, BAJK; Senadheera, GKR; De Alwis, AAP
The need for renewable energy sources in Sri Lanka is assessed and solar photovoltaics (PVs) is identified to be the most technically suitable and economically viable power source for the conversion of solar energy to electricity in future. Three generations of solar PVs comprising 1st, 2nd and 3rd generations are dentified, and Dye – Sensitized Solar Cells (DSSCs) comprising the 3rd generation cutting – edge solar cell technology is identified being the low-cost easy to manufacture, durable, stable, long life time with reasonably high solar energy to power conversion efficiency (11% max with expensive , scarce, synthetic dyes like Ruthenium bipiridyl complex technology ), or of about 1% with cheap, low-cost, abundant, non-toxic, environmentally friendly natural dyes of photosynthetic green plants. Natural dyes were selected to carry out further research and development work for practical applications. Research done on DSSC’s since inception in Sri Lanka were scrutinized and assessed at the Institute of Fundamental Studies (IFS), Hantana, Sri Lanka, and other Institutions in Sri Lanka. It has been observed that most of the research at the IFS has been done using very expensive synthetic Ruthenium metallic dyes and have achieved a high conversion efficiency of 10% in May 2001. DSSCs sensitized with 145 natural dyes of plants growing in Sri Lanka were electrically and electronically tested and the ethanolic dye extracts of natural Mangoostein fruit rind (deep purple colour) exhibited the best conversion efficiency (of about 1%.) . It was also observed that other natural dyes such as Ekkiriya wood, Egg plant fruit peel, Karawalla kabilla fruit, Banana flower inflorescence, Beetroot tuber, Turmeric root and Fire fern leaf (not endemic to Sri Lanka) yield relatively good conversion efficiencies. Natural dye-based DSSCs even though possess conversion efficiencies usually below 1%, may be improved by finding different additives. Such DSSCs are cost effective , easy to manufacture, environmentally friendly and stable . They are potential solar energy to electricity conversion devices for low power applications if further research is done to boost their conversion efficiencies to about 2% - 3%, and to increase their long term stability. The reasons why DSSC’s have not been developed for commercial use in Sri Lanka have been identified, assessed and remedial measures proposed. Research and development work were also initiated to develop practical DSSCs sensitized with low-cost abundant and environmentally friendly natural dyes of plants for low power applications such as battery charging of mobile telephones, iPod’s, portable radio communications equipment, LED operated multi – coloured garden - night lights of hotels etc., construction of Building Integrated Photovoltaic (BIPV) systems to provide diffused lighting with multicoloured LED operated lighting systems, provision of propulsion power to small boats etc, in order to assist solve the impending energy crisis when all known sources of fossil fuel will be exhausted in a few decades.
item: Thesis-Abstract
Reinforcement of natural rubber lates films with fine particle fillers
(2015-03-01) Somarathne, MCW; Liyanage, NMVK
Reinforcement of natural rubber latex (NRL) is essential for NRL based thin film products manufacture. Silica is one of the most important reinforcing fillers used in dry rubber industry. However, the surface bound silanol groups that are polar and considerably chemically active, make silica less compatible with NRL. In the present study, surface of precipitated silica (Ultrasil VN3) is modified with macromolecular coupling agents (MCAs) consisting of both hydrophilic and hydrophobic groups and the surface modified silica is incorporated into NRL in order to reinforce NRL films which is a novel concept introduced to confer interactions between silica-MCA complex and rubber particles. The MCAs are synthesized in the laboratory by a solution polymerization technique using hydrophilic and hydrophobic monomers. Surface modification of precipitated silica particles with the MCAs is carried out in two reaction mediums; aqueous and non-aqueous, separately. Unmodified/ modified silica is added as aqueous dispersions at neutral pH to compounded and uncompounded NRL in four different levels of loadings from 5 phr to 20 phr in 5 increments. Thin latex films are cast from compounded/uncompounded NRL filled with unmodified and modified fillers. Formation of H-bonds and/or covalent bonds between carboxylic groups of MCA and hydroxyl groups of silica is studied via FTIR spectroscopy and contribution of newly formed bonds in enhancing filler-rubber interactions is emphasized through mechanical, thermal and swelling properties. Microstructures of film cross sections of filler added NRL obtained from SEM and optical microscope confirm the uniform dispersion of modified filler particles throughout the rubber matrix. Tear strength and tensile strength are found to be increased by 50 % and 35 % respectively at 5-10 phr of filler loading of vulcanized films filled with filler modified by the most hydrophilic MCA compared with those of UM filler added vulcanizates. Keywords: Reinforcement, natural rubber latex, silica, surface modification, macromolecular coupling agents
item: Thesis-Abstract
Chemical modification of rubber waste and characterization of their blends with natural rubber
(2014-05-31) Edirisinghe, DG; Premachandra, JK
Ground rubber tyre (GRT) produced by recycling of tyre waste or rejects is used as a filler in the manufacture of tyre components, mainly to reduce the cost. Rubber matrix-GRT compositions generally exhibit poor mechanical properties due to poor matrix-filler adhesion and lack of reactive sites on GRT particle surfaces. Therefore, GRT is modified by employing various types of reclamation processes to enhance mechanical properties. The modified GRT known as reclaimed rubber is widely used as a component in rubber blends in many applications, especially in tyre manufacturing. This study is focused on developing a cost effective, environmental friendly mechano-chemical reclamation process for GRT to produce reclaim rubber using a readily available amino compound. Initially, influence of the amino compound on rubber compound properties was evaluated and results indicate that it acts as an activator for sulphur vulcanization. Properties of GRT modified with the amino compound indicate that the amino compound acts as a reclaiming agent as well. Comparison of properties of natural rubber (NR) / novel reclaimed rubber blend compounds and revulcanisates with those of the controls reveal that the former can be used as alternatives to the latter in the manufacture of tyre treads. Replacement of 30% of virgin NR in the vulcanisates with the novel reclaimed rubber retains about 65-85% of strength properties, elongation at break and resilience. Abrasion volume loss is at an acceptable level and ageing properties are comparable to those of the 100% virgin NR vulcanisate. Further, most of the properties of the virgin NR / novel reclaimed rubber composites are comparable to those of the corresponding composites prepared by blending NR with commercially available reclaimed rubbers. Accordingly, the novel reclaimed rubber could be a suitable component to blend with virgin NR in the manufacture of tyre treads with required properties.
item: Thesis-Abstract
Synthesis and characterization of novel alkyd resins based on Karawila seed oil
Prashantha, MAB; Amarasinghe, S
This research project mainly focused on developing air drying alkyds with 65% oil length which offer superior film properties using locally available a suitable fatty oil and also developing a mathematical model to predict the gel point acid value in manufacturing alkyd resins. Analysis of seed oil of 'Karawila' MC43 indicated that it was a fatty oil rich in conjugated trienoic acids with moderate amount of saturated fatty acids. The oil content of seed of MC 43 was about 24% and the weights of dried seeds were in the range 2.98 -7.93 g with weight ratio of kernel to seed in dry basis of about 0.6. Acid value of the oil was 2.73 mg g", saponification value was 190.70 mg g-l and iodine value was 115.96 cg g". The seed oil of MC43 showed better drying properties compared to common drying oils. A simple mathematical model was developed to predict the iodine value of fatty oils based on the total number of pi-bonds in the fatty acid profile (π) as Iodine value equals 0.8683 x π Since the acid value of seed oil of MC43 was comparatively low, monoglyceride process was selected in manufacturing alkyd resins. The optimum heating rate, mixing speed and the volume ratio were first established for the laboratory reactor used in the experiment. Better film properties could be obtained when a mixture of glycerol and pentaerythritol was used as polyols with excess OH. Film properties were compared by gradually increasing the pentaerythritol content while keeping oil length at 65% until the industrial specifications for film properties were obtained. Excellent film properties were obtained when the minimum ratio of pentaerythritol/glycerol was 0.33 and the OHICOOH ratio was in the range of 1.23 to 1.4. Satisfactory film properties were obtained when OHICOOH ratio was in between 1.23 to 1.48 with pentaerythritol / glycerol ratio within 0.23 to 0.33. When pentaerythritol / glycerol ratio was lower than 0.2, hardness was not acceptable. The results of kinetic studies on polyesterification of monoglyceride mixture based on seed oil ofMC43 with pthalic anhydride suggested that the way of assigning order to the reaction based on correlation coefficient was unsatisfactory. This was mainly due to the simultaneous occurrence of several reaction mechanisms associated with steric hindrance of reacting molecules. A new mathematical model was developed to predict the acid value at gel point based on the statistical approach of proposing the growth pattern of alkyd molecules during the polyesterification reaction. Proposed model was compared with the existing models using the actual data recorded in literature. The predicted acid values from the proposed model gave minimum deviation from actual data compared to existing models. However, the predicted acid values of alkyd resins based on MC43 seed oil deviated significantly from the experimental data due to the presence of conjugated trienoic acids in the fatty oil of MC43. Hence, a modification was introduced to incorporate the effects of dimerization reactions and the predicted results were then closely agreed with the actual data

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