Gas Engineering Department

Erosive wear can be caused by a water jet burst from leaked water pipe laid side by side to natural gas pipeline. The erosive wear behavior of natural gas pipeline eroded by sand and water jetting was investigated. This work present the erosive wear analysis of API 5L X42, steel grade pipeline which normally used for distributing natural gas to an industrial customers by gas utility company in Malaysia. Tests were carried out by recreating above mentioned situation through the usage of 5 mm diameter orifice as the source of jetting in sand particles towards the pipe specimen that was buried at 1 meter depth. The existence of tunneling effect was established by identifying the horizontal and vertical tunneling through physical examination of the impacted surface. It was determined that the thickness of the pipe decreases with time. Determination of time taken for the pipe to rupture was established at 220 hours after continuous jetting and zero effect distance is at 450 mm from the jetting source of the relevant tests condition.

Incident involving failures of 6 months old API 5L X42 (NPS8) and SDR 17, 125 mm medium density polyethylene pipe (MDPE) supplying natural gas to an industrial customer has caused serious 7 h supply disruption. Study was performed to identify the most probable cause of the pipes failures. The study conducted by reviewing the existing design and construction data, visual physical inspection, pipe material analysis, structural analysis using NASTRAN and Computational Fluid Dynamics analysis (CFD) using FLUENT. Investigations revealed that high pressure water jet from leaked water pipe had completely mixed with surrounding soil forming water soil slurry (high erosive properties) formed at a close vicinity of these pipes. Continuous impaction of this slurry upon the API 5L X42 pipe surface had caused losses of the pipe coating materials. Corrosion quickly ensued and material loss was rapid because of the continuous erosion of oxidised material that occurred simultaneously. This phenomenon explains the rapid thinning of the steel pipe body which later led to its failure. Metallurgical study using photomicrograph shows that the morphology of the steel material was consistent and did not show any evidence of internal corrosion or micro fractures. The structural and CFD simulation results proved that the location, rate and the extent of erosion failures on the pipe surfaces can be well predicted, as compared with actual instances.

The invention of automobile has greatly changed the human's life. Transportation has an enormous impact to the economy and environment. Due to the decreasing supplement of petrol source and the pollution brought by the combustion of petrol, several efforts have been taken to replace petrol vehicle. Natural gas vehicle had been invented as well as electrical car.

The use of compressed natural Gas (cnG) for vehicle has proved to improve emission quality, reduces dependency on mainstream fuels and increase lubrication oil lifespan. The successful utilization of cnG on the kriss Modenas 110cc has been proven by previous researcher. The current study is carried out in the attempt to improve the pressure regulator which is deemed crucial in the cnG fuel system. Various drawbacks of the previously implied unit prove the need for this study. This study begins with a comprehensive understanding of the pressure regulation system. critical design parameters are carefully selected and optimized accordingly to enhance the final prototype. The flow within the regulator is optimized using FLUENT TM while the structural integrity is backed by american Society of Mechanical engineer (aSMe) pressure vessel code aSMe Section Viii division 1 and related standards on threaded fasteners. The fabrication of the prototype has been formulated from findings and analysis on the design methodology using suitable machining techniques. The performance of the final prototype is obtained from the specially developed pressure regulator test bench.

Recently, ceramic membrane gradually acquired attention from researchers due to the advantages of ceramic’s behavior, which allows the ceramic to overcome the limitations of using polymeric membrane. This work focused on the fabrication of ceramic hollow fibre membrane from a ceramic suspension solution containing yttria-stabilized zirconia (YSZ), polyethersulfone (PESf), N-methylpyrrolidone (NMP) and dispersants using combined phase inversion sintering technique. In this study, ceramic hollow membrane precursors were sintered at different sintering temperature ranging between 1250°C and 1400°C. The influences of sintering temperature on the microstructure, porosity and pore size distribution, mechanical strength and pure water flux of ceramic hollow fibre membrane were investigated in detail. The results show an asymmetric structure of YSZ hollow fibre membrane containing finger-like structure and sponge-like structure. The sponge-like structure can serve as a separation layer, whi...

This research investigated the prospect of using bio-based substrates for dust decontamination purposes. Initially, bio-based novolac resin was prepared by condensation from the reaction between phenol, bio-oil phenolic fractions and formaldehyde in an acidic medium. The prepared novolac was later transformed to epoxide with epichlorohydrine and 30 percent sodium hydroxide solution. The epoxy formulation was later enhanced with varying amount of methyl ester (10 wt%, 20wt% and 30wt% ). The samples were characterised using various techniques such as FTIR, GC-MS, contact angle etc. Dust depositions and decontaminations tests were also conducted. The results indicated that the synthesized hydrophobic bio-based sample possed some dust cleaning characteristics which when fully enhanced would lead to the emergence of bio-based dust cleaning formulation will contribute immensely in mitigating the negative effect and toxicity of petroleum based products.

The hydrophobic properties as well as the presence of 1-octacosanol of taro wax extracted from taro leaf were investigated using various analytical techniques. The bio-wax extraction was achieved by immersing taro leaves samples in 500 mL chloroform at 50 o C for 30 seconds and the step was repeated for the same sample using fresh chloroform. The solvent was evaporated using rotary evaporator and the raw bio-wax solution was obtained. Hydrophobicity test showed the average time for the test was 981s which exceeded the 300 s limited for hydrophilicity. TGA results indicate the existence of multi-components in taro wax with the decomposition occurring at three stages. The DSC result showed that the taro wax is composed of at least two contents, ie lower content with smaller melting point range of 50 to 60⁰C as well as upper content with higher melting point range of 65 to 75⁰C. Contact angle of droplets of distilled water on the taro wax surfaces were found to be greater than 90⁰ and this confirmed its hydrophobic property. The n-octacosanol presented was identified through FTIR and GC-FID analyses. The functional compounds OH, CH 3 , CH 2 , and C=O were detected. From the GC-FID, the n-octacosanol was presented at 34.5 min compared to the standard solution. Plant base taro wax can be a source of sustainable and renewable hydrophobic material for use in HVAC application system.

There is significantly abundant portion of waste agricultural materials in the world serving as environmental challenge, however, they could be converted into useful value added products like activated carbon. Coconut shell based carbons were synthesized using physical activation by CO 2 and chemical activation with potassium hydroxide and potassium acetate. The BET surface areas and pore volumes are 361m 2 /g and 0.19cm 3 /g for physical activation, 1353m 2 /g and 0.61cm 3 /g for activation with KOH and 622m 2 /g and 0.31cm 3 /g for potassium acetate activated carbon. From the Fourier Transform Infrared Spectroscopy analysis, hydroxyls, alkenes and carbonyl functional groups were identified with more prominence on the chemically activated porous carbons. Thermogravimetric analysis (TGA) results showed occurrence of moisture pyrolysis at 105 o C, the pyrolysis of hemicellulose and cellulose occurred at 160-390 o C and lignin at (390-650 o C). Carbonization at 700 o C and 2hrs had highest yield of 32%. Physical activation yielded lower surface area with approximately 88% micropores. On the other hand, chemically activation yielded higher surface area with elevated mesopores. The porous carbons can be applied to salvage pollution challenges.

Identification and assessment of phenol and phenolic rich components of heavy oil fractions of biomass pyrolytic oil were conducted. The original bio-oil used for this study was derived from the pyrolysis of empty fruit bunch (EFB). It was separated into water soluble (light oil) and water insoluble (heavy oil) components by mixing it with water at 2:1 V/V ratio under ambient condition with vigorous stirring using centrifuge for 30mins. The raw bio-oil and the heavy oil fractions were later characterized using Fourier Transform Infra-Red (FTIR) and Gas chromatography-Mass spectroscopy (GC-MS) techniques in order to identify the function groups present and their compositions. The GC-MS results for the heavy oil indicated a high concentration of phenol and phenolic components, which was strongly supported by the presence of OH group (characteristic of phenol) from FTIR analysis. Utilization of bio-oil which was known to have a significant amount of phenol and phenolic rich components for phenolic, novolac or epoxy resin manufacture would significantly reduce the cost and negative environmental effects of the fossilbased resins.

Low-cost palm shell was used as a precursor for preparation of porous carbons via chemical impregnation with K2CO3 and microwave heating. Volumetric adsorption setup was used to measure the adsorption capacity of methane at 303.15 K under pressure up to 4 bars. The methane adsorption data was modelled by Langmuir, Freundlich, and Dubinin-Radushkevich (DR) isotherm equations. Langmuir and Freundlich models were found to have the best fit than DR isotherm. The kinetics of methane adsorption on the microwave porous carbon followed pseudosecond-order model equation. The highest methane adsorption capacity obtained was 3.533 mmol/g at 4 bar and 303.15 K. It was noticed that there is increase in adsorption with increased in initial pressure. The porous carbon displayed good adsorption characteristics for methane.

Corrosion in most processing equipment has always been a key research area. It is an important threat that needs to be prevented and controlled. Application of epoxy-based coatings on the surfaces of metallic parts is among the preventive measures but it is toxic and expensive. In this work, the anticorrosion performance of zinc ferrite pigmented bio-based epoxy-novolac coatings was studied. Initially, bio-based novolac resins were prepared by condensation from the reaction between phenol, bio-oil phenolic fractions and formaldehyde in an acidic medium. The prepared novolac was later transformed to epoxide with epichlorohydrine and 30 percent sodium hydroxide solution. The final coating formulation was obtained by mixing the prepared epoxy with zinc ferrite (a nontoxic anticorrosion pigment) and solvent. Anticorrosion tests using the formulated coatings and two other conventional coatings for comparison were conducted by simulating actual field conditions in a closed autoclave loop system that used 3 percent sodium chloride and water medium. The results showed that the zinc ferrite pigmented bio-based formulated coatings are very efficient in protecting the substrates since they exhibit similar protection ability with the conventional ones. The prepared epoxy can be said to be an eco-friendly and cheap source of resin for coating formulation that will reduce production cost and negative environmental effects as compared to conventional materials

Bio-oil derived from the pyrolysis of a sustainable palm biomass has great potential as a suitable replacement to the conventional source of fuels and chemicals. However, the bio-oil produced is highly acidic and corrosive due to presence of acids that can leads to operational difficulties. As such, purification of the bio-oil for the targeted application as chemicals or fuel source needs to be conducted. This study is aimed at conducting further study on the isolation of insoluble fractions (heavy oil) of bio-oil and at the same time assesses the corrosiveness of the insoluble fractions and compare with that of raw bio-oil. This was done in order see whether the corrosive properties of the raw bio-oil are associated with these fractions or not. It was later upgraded using various ratio of zero valence aluminium metal as corrosion inhibitor. The raw biooil and the upgraded heavy oil fractions samples were characterized using various techniques. The results indicate significant improvement on the various properties tested on the side of upgraded heavy oil fractions than the raw bio-oil. Thus, realization of bio-oil quality for its subsequent application as fuel can significantly reduce operational difficulties in engines and other processing equipment.

Epoxy resins are among the basic components for coatings manufacture but because of their cost and environment effects, some environmental protection regulations have restricted the use of chemicals considered toxic. The potential of using phenolic rich fractions of bio-oil derived from the pyrolysis of a sustainable agricultural waste for epoxy resin synthesis was investigated. Epoxy resins with different concentration of water-insoluble heavy fraction were synthesized. The bio-oil, heavy fraction and prepared resins were later characterized using Fourier Transform Infra-Red (FTIR), Gas Chromatography Mass Spectrometry (GC-MS) and Differential Scanning Calorimetry (DSC). FTIR and GC-MS results confirmed the presence of phenols on both the bio-oil and heavy fraction with heavy fraction having a higher concentration. DSC analysis showed a corresponding increase on curing time of the resins with increased quantity of phenolic rich components. FTIR analysis of the resin indicated high-ortho structure. Utilization of bio-oil as a source of phenol for epoxy resins manufacture would significantly reduce the cost and negative environmental effects of the current resins.

Effluents from various industries release volatile organic compounds (VOCs) into the environment which causes serious environmental problems. Coconut shell based porous carbons (CSPC) were synthesized with potassium hydroxide as activating agent for adsorption of Benzene and Toluene. Central composite design (CCD) method under the response surface methodology (RSM) of the Design expert software version 7.1.6. was employed in the optimization of the preparation conditions of the porous carbons. The effects of three preparation variables (i.e. microwave power, irradiation time and KOH impregnation ratio) on Benzene and Toluene adsorption were studied. Based on the CCD, quadratic models were developed to correlate the preparation variables to the responses (Benzene and Toluene adsorption). The influence of process parameters on the properties of CSPC was examined using analysis of variance (ANOVA) to identify the significant parameters. The optimum condition was obtained at microwave power of 500W; irradiation time 4mins; and 1.5 KOH impregnation ratio, which resulted in 84% of Benzene and 85% of Toluene respectively at 95% yield.

Aeration is one of the most important factors in biological wastewater treatment process. Through aeration, oxygen is supplied to the bacteria to allow their respiration to proceed rapidly and satisfy the biochemical oxygen demand (BOD). This study was carried out to determine the biological growth in aerated palm oil mill effluent (POME) when subjected to aeration using air of different oxygen concentration. Pure oxygen (101% O 2 ), diffused air (20.9% O 2 ), and oxygen-enriched air (26.7% O 2 ) were used to aerate the POME for three weeks continuously at a flow rate of 0.1 LPM. Oxygen enriched air was supplied by an oxygen enriched air system (OEAS). This system is able to enriched oxygen concentration of air up to 26.7% using membrane with composition consisting of 22% polysulfone, 31.8% dimethylacitemide, and 14.4% ethanol. Samples subjected to aeration with air of three different oxygen concentration were tested for several water quality parameters which include pH, temperature, BOD, chemical oxygen demand (COD), dissolved oxygen (DO), total solid (TS), total suspended solid (TSS), bacterial count, saturated dissolved oxygen (SDO) and dissolved oxygen deficit for every two days. It was found that bacteria count and BOD reduction in POME when aerated by OEAS was 13.8% and 18.3% respectively more than when it was aerated by diffused air. This shows that an increased in oxygen concentration during aeration can speed up the microbial growth and thus shortened the period of aerobic digestion process.