MookTzeng Lim | University of Canterbury/Te Whare Wānanga o Waitaha (original) (raw)

MookTzeng Lim

Mooktzeng (Miller) is a consultant in NexantECA, providing insights and foresights on processes and technologies for the energy and chemical sector. He has developed detailed technoeconomic and carbon intensity studies for subscription reports, including ethylene, propylene, and xylene. Mooktzeng has a cumulative 15 years of commercial, industrial, research experience (UK and NZ) in the biomass, cement, chemical, aluminum substrate and power sectors. He has more than 10 years of research experience, including with the research institution of Malaysia's state-owned utility company, Newcastle University (UK), Univ. of Canterbury (NZ), and Univ. Teknologi PETRONAS.

Mooktzeng has filed 11 intellectual properties related to biomass and plasma technologies. His main achievements include: (1) improved biofuel quality by reducing 80 percent of fouling and slagging issues, (2) developed and commissioned a 1 ton per hour biomass pre-treatment system that was co-funded by South Korea, (3) Spearheaded effort to commercialize biomass pre-treatment plant [USD 5 mill], a non-thermal plasma combustion system [USD25 000], and a power-to-X or e-methanol system, (4) conducted trial burn & analysis of 75 tons of higher quality biomass in a 10 MW(e) power plant, and (5) pioneered a biomaterial integrated perovskite solar cell research lab. He has provided expert advice to an international chamber of commerce and other organizations on biomass and plasma technologies. Mooktzeng has also been invited as a guest lecturer and panelist on several occasions.
Experiences
He has a wide-ranging experience, from a mechanical engineer in the cement, chemical, aluminum substrate industries; to measuring particulate matter emissions from boilers using Strohlein, Wohler methods in Denmark; tutoring in Newcastle; learning about external cavity diode lasers in Hiroshima; to a 100 kW dual fluidized bed gasification system in New Zealand; and commissioning pilot scale projects related to biomass and plasma technologies.

Mooktzeng graduated with PhD in Chemical & Process Engineering from Univ. of Canterbury (NZ), is a Chartered Engineer, Mentor, Senior Assessor, CPD Auditor with the Institute of Mechanical Engineers (IMechE, UK) and a registered Professional Engineer with the Board of Engineers Malaysia (BEM).

Owing to his wide experience and knowledge, he has been invited as a panelist, moderator, speaker and adjust lecturer to high level stakeholder events. His expertise is sought after for the biomass industry and sectors requiring decarbonization.
Phone: 0322987240
Address: NexantECA, The Gardens South Tower

less

Uploads

Papers by MookTzeng Lim

Journal of Telecommunication, Electronic and Computer Engineering, 2016

To ensure the sustainability of fuel resources and to reduce cost from thermal processes such as ... more To ensure the sustainability of fuel resources and to reduce cost from thermal processes such as combustion, a nonthermal plasma device (NTP) was proposed in this study. NTP devices have been known to reduce pollutants in flue gas and also assist in combustion. As opposed to thermal plasmas, NTPs utilize the energy to create radicals or excited species of the carrier gases that flow through the device. Before the NTP device is applied for combustion, its performance (namely, the amount of energy it consumes and generates) needs to be characterized. Thus, this study investigates the discharge characteristics of two different types of NTP configuration – dielectric barrier discharge (DBD) reactors with (a) wire-cylinder and (b) wirewindings arrangements. The power consumption and discharge power were also measured to determine their efficiency. The discharge power was determined via the Lissajous diagram, which is a plot of the charge accumulated in the discharge against the discharge...

Plasma Chemistry and Plasma Processing

ACS Omega

This work established a high-speed camera-assisted visualization system that investigated the eff... more This work established a high-speed camera-assisted visualization system that investigated the effect of volatile matter and fixed carbon content in biomass particles on single-particle combustion phases and their luminous properties. Three types of biomass particles, namely, sawdust (a mixture of pine and willow), corncob, and rice husk, were examined on a Hencken flat-flame burner. The luminous region and intensity of single biomass particles were closely related to the flammability and calorific value of biomass fuel and derived by analyzing a sequence of images captured using a high-speed camera. The combustion temperature was determined through analysis of its radiant energy. The results showed that the ignition mechanisms of volatile matter and fixed carbon corresponded to homogeneous and heterogeneous reactions, respectively. The maximum luminous region values of 1.75 × 10 6 , 2.1 × 10 6 , and 1.0 × 10 6 μm 2 for sawdust (SD), corncob (CC), and rice husk (RH) correlated to the volatile matter content of each biomass sample, which was 69.38, 74.15, and 64.56%, respectively. Because of the high fixed carbon content, the peak temperature of the SD particles could reach 1549°C. The luminous region and intensity of the combusting particles were significantly affected by the volatile matter and fixed carbon, respectively.

IOP Conference Series: Earth and Environmental Science

This study shows that pre-treatment of empty fruit bunches (EFB) has a positive impact on the ene... more This study shows that pre-treatment of empty fruit bunches (EFB) has a positive impact on the energy content of syngas from the gasification process. In Malaysia, there is an estimated 25 million tonnes of EFB which can be used for power generation or for producing value added products through gasification. Gasification is a thermochemical process where the oxidant (air) is lower than the stoichiometric requirement, thus producing volatile syngas such as carbon monoxide, methane, hydrogen that contribute to the energy content. However, EFB has relatively higher ash and alkali metal content compared to other types of biomass, such as wood. Alkali metal contents such as potassium and sodium (K and Na) have been reported to reduce the initiation temperature for the formation of slag and clinker, and can cause operational issues for gasification systems, though other results show that alkali metals increase the gasification reactivity. Pre-treatment of the EFB may be required for reduci...

Plasma Science and Technology

The effects of non-thermal plasma (NTP) treatment on biomass in the form of pulverized palmbased ... more The effects of non-thermal plasma (NTP) treatment on biomass in the form of pulverized palmbased empty fruit bunches (EFB) are investigated. Specifically, this study investigates the effects of NTP treatment on the surface reactivity, morphology, oxygen-to-carbon (O/C) ratio of the EFB at varying treatment times. The surface reactivity is determined by the reaction of antioxidant functional groups or reactive species with 2,2-diphenyl-1-picrylhydrazyl (DPPH). By measuring the concentration of the DPPH with a spectrophotometer, the change in the amount of antioxidant functional groups can be measured to determine the surface reactivity. The reactions of the various lignin components in the EFB with respect to the NTP treatment are discussed by qualitatively assessing the changes in the Fourier transform infrared (FTIR) spectra. The surface morphology is examined by a scanning electron microscope. To determine the amount of oxygen deposited on the EFB by the air-based NTP treatment, the oxygen and carbon contents are measured by an energy dispersive x-ray detector to determine the O/C ratio. The results show that the NTP reactor produced reactive species such as atomic oxygen and ozone, increasing the surface reactivity and chemical scavenging rate of the EFB. Consequently, the surface morphology changed, with an observed rougher surface from the images of the EFB samples. The change in the appearance of the surface is accompanied by a high O/C ratio, and is caused by reactions of certain components of lignin due to the NTP treatment. The lignin component that was modified is believed to be syringyl, as the syringyl portion in the lignin of EFBs is higher compared to the other components. Syringyl components are detected in the range of FTIR wavenumbers of 1109-1363 cm −1. With increasing NTP treatment times, the absorbance (of the peaks in the FTIR spectra) for syringyl related C−H and lignin associated C=C bonds decreases as the syringyl decomposes. The resulting release of carboxyl compounds increases the absorbance for the carbonyl C=O group. The results show that NTP treatment is able to modify the surface properties of EFB, and that the surface reactivity can be increased to improve their conversion and processing efficiencies.

IOP Conference Series: Materials Science and Engineering

This paper presents image processing techniques with the use of fuzzy logic and neural network ap... more This paper presents image processing techniques with the use of fuzzy logic and neural network approach to perform flame analysis. Flame diagnostic is important in the industry to extract relevant information from flame images. Experiment test is carried out in a model industrial burner with different flow rates. Flame features such as luminous and spectral parameters are extracted using image processing and Fast Fourier Transform (FFT). Flame images are acquired using FLIR infrared camera. Non-linearities such as thermal acoustic oscillations and background noise affect the stability of flame. Flame velocity is one of the important characteristics that determines stability of flame. In this paper, an image processing method is proposed to determine flame velocity. Power spectral density (PSD) graph is a good tool for vibration analysis where flame stability can be approximated. However, a more intelligent diagnostic system is needed to automatically determine flame stability. In this paper, flame features of different flow rates are compared and analyzed. The selected flame features are used as inputs to the proposed fuzzy inference system to determine flame stability. Neural network is used to test the performance of the fuzzy inference system.

Food waste and food loss are used to describe materials that are actually produced for consumptio... more Food waste and food loss are used to describe materials that are actually produced for consumption, but are discarded, lost, degraded or contaminated. Food waste is one of the main parts of municipal solid waste. Landfill is not preferable when compared with other types of waste handling method. It has been reported that the impact of landfill on climate change can be ten times higher than other waste handling methods. However, most FW end up in landfills. This paper reviewed the performance of several food waste pre-treatment technologies to convert FW into feedstock for incinerators/boilers in terms of electrical power generation purposes. The performance of food waste pre-treatment methods and their products were extensively discussed and compared in this paper in terms of calorific value, energy density, and compound reduction, which later directly corresponded with the energy, environmental, and economic factors for the sustainability of future renewable power generation.

Other than usage for environmental remediation, ozone is also increasingly studied for its potent... more Other than usage for environmental remediation, ozone is also increasingly studied for its potential in combustion enhancement. In this study, the characterization of the ozone production at varied voltage, duty cycle and cylinder configuration for reactor was conducted using multivariable power least squares method (MPLSM). This alternative correlation method in the form of power function was applied in this study to determine the dominant factor affecting the ozone production using the multi-cylinder reactor. The regressed equation using MPLSM method indicated voltage as the dominant factor in the production of ozone compared to the effect of duty cycle. The correlations generated from MPLSM for both reactor configurations were able to predict most of the ozone concentration results within 25% deviation from the actual experimental data. As such, MPLSM could be considered as an alternative method to be used for correlations of non-polynomial results.

Plasma Chemistry and Plasma Processing, 2020

A non-thermal plasma (NTP) device is developed to improve the combustion efficiency of sustainabl... more A non-thermal plasma (NTP) device is developed to improve the combustion efficiency of sustainable fuels such as biomass. Typical boiler efficiencies range from 75-86%, with losses due to inefficiencies such as dry flue gas losses, in which the excess air that is heated up for combustion is unutilized. Efforts to improve combustion efficiencies is complicated by future needs of utilizing sustainable fuels (biomass) with conventional fossil fuels to reduce climate impacts. In order to mitigate these challenges and to improve the efficiency in a narrow operating range of optimum conditions, an adaptive technology is required. Such technology should be versatile enough for the varying characteristics of alternative fuels, and should be easily retrofitted to existing operations. In this study, a NTP device is developed and integrated with a 150 kWth combustion test facility to investigate the effects of the reaction of ozone (generated from the NTP) on the combustion of biomass and coal in terms of the rate of heating, flue gas composition and dry flue gas losses. Simulation of the ozonolysis with the volatile organic compounds is also performed to validate the experimental results. For biomass combustion, an increase in the intensity of the NTP decreases the dry flue gas losses. For coal combustion, the dry flue gas loss increases with increase in power of the NTP. The difference in the results is caused by the difference in the volatile organic compounds (VOC) for biomass compared to coal, and their subsequent reaction with ozone (ozonolysis). Ozonolysis of alkanes and aromatics increases the CO2 content and reduces the dry flue gas losses. Ozonolysis of alkenes yield higher CO, as reported by literature and validated by simulation results, increasing the dry flue gas loss. The simulation and results from literature indicates that the VOC composition in the coal used in this study is more likely to compose of more alkenes compared to alkanes. The results also show that the NTP has the potential to optimize efficiencies in existing combustion systems.

In order to address slagging, fouling and high-temperature corrosion problems caused by alkali me... more In order to address slagging, fouling and high-temperature corrosion problems caused by alkali metals in Municipal Solid Waste (MSW), in-situ measurement of alkali metal in MSW incinerators is needed. The paper presents experimental measurements of temperatures and alkali metal concentrations in two MSW incinerators based on Flame Emission Spectroscopy (FES). Through the analysis of spontaneous emission spectra and a calibration procedure, the concentration of gas phase sodium (Na) and potassium (K), temperature and thermal radiation in the incinerator were in-situ measured by a portable spectral system simultaneously. Experimental results showed MSW composition has significant effect on the measured gaseous Na and K. Higher volatile content in MSW may enhance the alkali metal emission. Besides that, the released gaseous Na and K in the two incinerators are correlated with temperature in incinerators. The study provided a low cost and effective solution for in-situ measurement of temperature and alkali metal concentration in MSW incinerators.

Chemical Engineering Communications, 2019

A portable, simplified and in-situ method based on optical emission spectroscopy to quantify the ... more A portable, simplified and in-situ method based on optical emission spectroscopy to quantify the alkali metal emissions and its speciation from the combustion of biomass is presented. The quantification relates the ratio of the relative number densities of alkali metals in the ground state with the ratio of alkali metal oxides in the ash samples. The comparison of the ratios tentatively reveals the speciation of the alkali metals, namely, sodium and potassium in the ash. The results show that the method is able to provide a better understanding of the reaction pathways for the alkali metals that could take place in a furnace.

Energy, 2019

The spray combustion characteristics of sunflower (Helianthus annuus) biodiesel/methyl esters (SF... more The spray combustion characteristics of sunflower (Helianthus annuus) biodiesel/methyl esters (SFME) and 50% SFME/diesel blend and diesel were investigated via
a liquid swirl flame burner. The swirl flame was established at atmospheric condition by using a combined twin-fluid atomiser-swirler configuration at varied atomising air-to-liquid ratios (ALR) of 2.0 -2.5. Diesel flame showed a sooty flame brush downstream of the main reaction zone, as opposed to the biodiesel flame which showed a non-sooty, bluish flame core. Biodiesel
flame exhibited a more intense flame spectra with higher OH* radicals as compared to diesel.
Higher preheating main swirl air temperature led to higher NO emission, while CO correspondingly decreased. Sunflower-derived biodiesel generally exhibited slightly higher NO and CO levels than diesel when compared at the same power output, mostly due to higher
flame temperature and fuel chemistry effect. By increasing ALR, a significant reduction of NO
and CO for both fuel types were concurrently achieved, presenting a strategy to control emissions and atomise biodiesel with higher viscosity under swirl combustion mode.

Fuel, 2019

The paper presents experimental investigation on temporal release of potassium (K) from single bi... more The paper presents experimental investigation on temporal release of potassium (K) from single biomass pellet combustion by Flame Emission Spectroscopy (FES). Through the analysis of spontaneous emission spectra and a calibration procedure, the concentration of gas phase potassium, temperature and thermal radiation during the whole process of biomass pellets combustion in a Hencken burner were measured simultaneously. Camphorwood and rice husk with volatile matter 87.93%, 69.12%, respectively, and K 2 O content from the ash analysis 7.99%, 1.8%, respectively, were used in the experiment. The effects of biomass composition and moisture content in the pellet on the temporal release of K were analyzed. Experimental results showed the three stages (devolatilization, char, and ash stage) of biomass pellets combustion can be distinguished by the changing points of K concentration, temperature and thermal radiation curves obtained by the FES. The volatile content in biomass pellet has effect on the release behavior of K. The change of moisture in biomass pellet may affect significantly the ratio of K release from biomass pellet with low volatile. The experimental investigation proves FES is feasible for on-line monitoring the K release and combustion process of biomass pellet.

Journal of the Japan Institute of Energy, 2017

The flame emission spectra were measured from the combustion of biomass in a boiler, from which t... more The flame emission spectra were measured from the combustion of biomass in a boiler, from which the ratio of the alkali metals’ number densities (sodium and potassium) were precursory derived. Fly and bottom ash samples were collected to determine their composition via scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDX). A comparison of the alkali metals’ number density ratios (from the flame emission spectra) and the ash composition provided information on potential pathways for the alkali metals. The comparison also showed that the number density ratio can be taken as a tentative in-situ indicator of the alkali metals’ ratio. The ash composition also allowed the determination of several slagging and fouling indices

Plasma Science and Technology, Jul 26, 2017

Non-thermal plasma (NTP) devices produce excited and radical species that have higher energy leve... more Non-thermal plasma (NTP) devices produce excited and radical species that have higher energy levels than their ground state and are utilized for various applications. There are various types of NTP devices, with dielectric barrier discharge (DBD) reactors being widely used. These DBD
devices vary in geometrical configuration and operating parameters, making a comparison of their performance in terms of discharge power characteristics difficult. Therefore, this study proposes a dimensionless parameter that is related to the geometrical features, and is a function
of the discharge power with respect to the frequency, voltage, and capacitance of a DBD. The dimensionless parameter, in the form of a ratio of the discharge energy per cycle to the gap capacitive energy, will be useful for engineers and designers to compare the energy characteristics of devices systematically, and could also be used for scaling up DBD devices. From the results in this experiment and from the literature, different DBD devices are categorized into three separate groups according to different levels of the energy ratio. The larger DBD devices have lower energy ratios due to their lower estimated surface discharge areas and capacitive reactance. Therefore, the devices can be categorized according to the energy ratio due to the effects of the geometrical features of the DBD devices, since it affects the surface
discharge area and capacitance of the DBD. The DBD devices are also categorized into three separate groups using the Kriegseis factor, but the categorization is different from that of the energy ratio.

—To ensure the sustainability of fuel resources and to reduce cost from thermal processes such as... more —To ensure the sustainability of fuel resources and to reduce cost from thermal processes such as combustion, a non-thermal plasma device (NTP) was proposed in this study. NTP devices have been known to reduce pollutants in flue gas and also assist in combustion. As opposed to thermal plasmas, NTPs utilize the energy to create radicals or excited species of the carrier gases that flow through the device. Before the NTP device is applied for combustion, its performance (namely, the amount of energy it consumes and generates) needs to be characterized. Thus, this study investigates the discharge characteristics of two different types of NTP configuration – dielectric barrier discharge (DBD) reactors with (a) wire-cylinder and (b) wire-windings arrangements. The power consumption and discharge power were also measured to determine their efficiency. The discharge power was determined via the Lissajous diagram, which is a plot of the charge accumulated in the discharge against the discharge voltage. The Lissajous diagram of both configurations was a parallelogram, typical of DBDs. The wire-windings arrangement required lower sustaining voltage and was generally more efficient in terms of power consumption.

This paper investigates the effects of four reaction parameters that include type of catalyst, ca... more This paper investigates the effects of four reaction parameters that include type of catalyst, catalyst loading, reaction
temperature and nitrogen gas flowrate on the liquid (bio-oil) yield from the catalytic pyrolysis of Empty Fruit Bunch (EFB). The
experimental design is based on Taguchi’s L9 Orthogonal Array in which the reaction parameters are varied at three levels. The
maximum liquid yield is predicted based on systematic experimental runs, and is found to be at 5 wt-% of H-Y catalyst, 500°C and at
nitrogen flowrate of 100 ml min-1. The predicted maximum liquid yield is validated with an experimental run at the corresponding
predicted conditions. The bio-oil produced at the optimum reaction condition is characterized and compared with known bio-oil
standards in the literature.

An atmospheric air non-thermal plasma (NTP) device is characterized in relation to ozone producti... more An atmospheric air non-thermal plasma (NTP)
device is characterized in relation to ozone production. The electron density, ne, electron temperature, Te and ozone concentration are measured for three dielectric barrier discharge (DBD) geometries, i.e., ten tubes of 10 mm outer diameter (OD), six tubes of 25 mm OD, and three tubes of 40 mm OD. ne and Te are deduced using optical emission
spectroscopy via the line ratio method and the ozone concentrations are measured by using an ozone meter. ne and ozone concentrations were the highest for the three tube-40 mm configuration, showing a correlation between the number of charged particles and ozone production.

Powder Technology, 2012

Design of a fluidized bed gasification plant requires a good understanding of how operating param... more Design of a fluidized bed gasification plant requires a good understanding of how operating parameters influence solids circulation, because this affects the heat transfer that sustains the reactions in the system. In this paper, the effect of various operating parameters, such as primary and secondary fluidizing airflows, on solids circulation within a scaled-down cold model of a circulating fluidized bed (CFB) was investigated. An operational map was developed to show regions of stable CFB operation and boundaries of unsatisfactory CFB operation, when fluidization becomes highly unsteady or inefficient due to gas bypass. Under stable operation, it was observed that solids circulation increased with an increase in primary and secondary fluidizing airflows and solids inventory of the plant. Provided the loop seal was fluidized properly, any changes in operating parameters resulted in the solids flow adjusting accordingly to maintain a proper gas seal and ensure stable operation. The operating parameters also affected the pressure drop across various points in the CFB, essentially due to redistribution of solids within the system. A new semi-empirical model was developed to estimate the ratio of solids that exit the CFB riser to solids that recirculate back into it. This model was based on considerations of the outlet geometry and solids inertia, in particular the ability of the solids to resist the change in direction of the airflow as it curves towards the exit of the CFB riser.