Alina Rahayu Mohamed
Thumbnail Image
Preferred name
Alina Rahayu Mohamed
Official Name
Alina Rahayu, Mohamed
Alternative Name
Rahayu, M. Alina
Mohamed, Alina Rahayu
Rahayu Mohamed, Alina
Main Affiliation
Scopus Author ID
55349453800
Researcher ID
DHI-6721-2022

Research Output

Filters

5 1
25
Reset filters

Settings
Now showing 1 - 10 of 25
Thumbnail Image
Publication

Thermal pyrolysis of empty fruit bunch (EFB) in a vertical fixed-bed reactor

2020 , Alina Rahayu Mohamed , A N Awang , Noor Hasyierah Mohd Salleh , R Badlishah Ahmad

In the production of crude palm oil, huge quantities of solid biomass waste is generated such as empty fruit bunch (EFB), palm fronds and palm–pressed fibre (PPF). This inevitably resulted in the environmental pollution due to its natural conversion to methane. In this study, thermal pyrolysis of EFB was conducted using a fixed bed reactor. The factors such as nitrogen gas flowrate and holding time that affect the distribution of pyrolysis product yields were being investigated by evaluating the percentage product yields. It was determined that at nitrogen gas flowrate of 300 cm3/min and 30 mins holding time, the maximum bio-oil yield of 46.20 % was attained with gas and char yield of 21.79 % and 32.01 % respectively. The existence of functional groups in bio-oil was analyzed by Fourier Transfrom Infra-Red (FTIR) spectroscopy. It was identified that the bio-oil has several functional groups such as hydroxyl (OH), ketone/aldehyde (C=O) and ester (O-C=O) groups. The dynamic viscoscity of bio-oil was analyzed by Brookfield viscometer. It showed that the viscosity of bio-oil decreased with increasing temperature from 25-50 °C.

View
No Thumbnail Available
Publication

Thermal characteristics of Malaysian Khaya Senegalensis wood fuel pellets: densification-induced changes at different feedstock moisture levels

2025 , Ras Izzati Ismail , Alina Rahayu Mohamed

This study investigates the thermal behaviour of Malaysian Khaya senegalensis wood energy pellets, examining the effects of densification at different feedstock moisture levels. Densified wood pellets are promising renewable energy sources, but the impact of densification on thermal characteristics, considering various moisture contents, is underexplored. The main objective is to quantify the thermal characteristics, which involved proximate analysis such as energy pellets’ ash content, fixed carbon, volatile matter, and calorific value. In this research, Malaysian Khaya senegalensis wood was converted into pellets through a densification process, spanning from of 4-20% feedstock moisture levels. The manufactured pellets were then subjected to various tests to characterize the thermal properties. Results reveal compelling insights on the relationships between densification, moisture content, and thermal properties. Densification significantly influenced thermal attributes, with effects tied to initial moisture content. Varying moisture levels led to distinct thermal responses, reflecting interactions between densification-induced changes in moisture and thermal responses. In this study, the best moisture content for ash content was found to be 16%, with 3.24% ash content, 16% moisture content with volatile matter of 85.24%, fixed carbon of 12% from 20% moisture content, and 16% moisture content with calorific value of 19.65 MJ/kg. These findings aid Khaya senegalensis wood pellet densification optimization for improved thermal performance. Understanding densification's impact on thermal behaviour under varying moisture conditions enhances pellet efficiency as sustainable energy sources. This research contributes to biomass pellet knowledge for renewable energy applications, advancing efficient and eco-friendly energy solutions.

View
No Thumbnail Available
Publication

Comparative Performance of Catalytic and Non-Catalytic Pyrolysis of Sugarcane Bagasse in Catatest Reactor System

2020-04-30 , Faraheen Kabir Ahmad S. , Umi Fazara Md Ali , Khairuddin Md Isa , Alina Rahayu Mohamed , Sataimurthi O.

Catalytic pyrolysis is a favourable process used to enhance the quality of bio-oil. Based on reviews from previous research there are only scarce of studies on the comparison of catalytic and non-catalytic pyrolysis of biomass such as rice husk, olive husk and corncob. In this study, sugarcane bagasse was selected as it has not been explored much yet. The target of this research is to compare the impact of catalytic and non-catalytic pyrolysis of sugarcane bagasse in terms of the yield, properties, and also the compositions of bio-oil. Catalytic and non-catalytic pyrolysis was executed in catatest bed reactor at temperatures 400°C to 550°C with the aids of ZSM-5 zeolite catalyst. Bio-oil from catalytic and no-catalytic pyrolysis which gives the maximum yield was used to be studied further in terms of the properties and chemical compositions. The result shows that the maximum yield of bio-oil was accomplished from catalytic pyrolysis at temperature 500°C which was 21.4%. The properties and composition of bio-oil from catalytic pyrolysis shows better result compare to non-catalytic pyrolysis.

View
Thumbnail Image
Publication

Durability Studies of Solid Pellets from Torrefied Leucaena Leucocephala

2020-12-18 , Kee Wei Chin , Alina Rahayu Mohamed , Zin A.M. , Noor Hasyierah Mohd Salleh , Aziz A.H.A. , Mohd Qalani Che Kasim

Torrefaction of Leucaena Leucocephala was performed in a fixed bed reactor at temperature of 300 C and 20 minutes holding time under inert environment. The torrefied Leucaena Leucocephala was pelletized with starch as the binder. Two parameters were investigated such as different ratio of starch addition to torrefied Leucaena Leucocephala pellets and the thickness of torrefied Leucaena Leucocephala pellets towards its durability. The ratios of starch addition to torrefied Leucaena Leucocephala pellets studied were 0, 5,10,15,20 and 25 wt%. Meanwhile, the studied thickness of torrefied Leucaena Leucocephala pellets were 0.3, 0.4, 0.5, 0.6 and 0.7 cm. It was observed that when the ratio of starch addition to torrefied Leucaena Leucocephala pellets was varied from 0-25 wt%, the durability increased steadily and the highest durability of 56.06% was achieved at 20 wt%. When the thickness of torrefied Leucaena Leucocephala pellets was increased from 0.3-0.7 cm, the highest durability of 93.18 % was achieved at 0.5 cm thickness. Scanning Electron Microscope (SEM) analysis was performed on the torrefied Leucaena Leucocephala pellets of 0 and 20 wt% ratio of starch addition. SEM images show the existence of some minor pores on the surface of torrefied Leucaena Leucocephala pellet at 250X and 1000X magnifications.

View
Thumbnail Image
Publication

Durability properties of demineralized and torrefied Empty Fruit Bunch (EFB) pellets

2020 , Alina Rahayu Mohamed , Ras Izzati Ismail , Rashid, Mohammad Abdur , Khairunissa Syairah Ahmad Sohaimi , N N Kasim , R Badlishah Ahmad

The pelletization of raw and demineralized and torrefied empty fruit bunch (TDEFB) were conducted upon mixing with bio-oil that was obtained from EFB pyrolysis. The ratio of bio-oil addition to raw and TDEFB was varied from 0-20 wt%. Then it was pressed using the single pellet press machine. The effects of the ratio of bio-oil addition to raw and TDEFB and the thickness of pellets were evaluated towards its durability. It was identified that the ratio of bio-oil addition to raw and TDEFB pellet of 5 wt% had produced the optimum durability which was 69.27 and 74.46 % respectively. In terms of the thickness of the raw and torrefied pellets, it was determined that at thickness of 3 cm, the durability was the highest which were 70.12 and 71.12 % for both raw and TDEFB pellets respectively. The raw and TDEFB pellets were analysed using Fourier Transform Infra-Red (FTIR) spectroscopy in order to evaluate the presence of functional groups within the materials. The presence of O-H hydroxyl group, C=O from carbonyl or ester and C-H alkane groups are detected in both raw and torrefied pellets.

View
Thumbnail Image
Publication

Thermal and catalytic pyrolysis of palm-pressed fibre with copper oxide doped zirconia CuO/ZrO₂ catalyst in a fixed-bed reactor

2020 , Alina Rahayu Mohamed , Aznie Nadiera Awang , D M Hassan , N Nordin , R Badlishah Ahmad

The utilization of agriculture solid waste such as palm pressed fibre (PPF) in pyrolysis reaction is an alternative way in converting the solid waste into bio-oil. In this research, thermal and catalytic pyrolysis of PPF was conducted using a tubular fixed bed reactor. A series of CuO/ZrO₂ catalysts were prepared using the aqueous sol-gel technique. The catalysts were calcined at 400, 600 and 800 °C for 17 hours. The thermal and catalytic pyrolysis of PPF were carried out at 500 °C pyrolysis temperature for 5 minutes holding time using PPF particle size of 250-500 µm. The pyrolysis results showed that 44.35% bio-oil was obtained under thermal condition and their yields reduced to 41.07%, 35.45% and 38.18% respectively when CuO/ZrO₂ catalysts calcined at 400, 600 and 800 °C were incorporated in PPF pyrolysis. The bio-oil was analyzed by using fourier transform infrared (FTIR) spectroscopy for the determination of functional groups. It was found that bio-oil from thermal and catalytic conditions possessed oxygenated functional groups such as aldehyde, ketone and carboxylic acid. In addition, the bio oil from catalytic conditions CuO/ZrO₂ catalysts calcined at 400 and 600 °C showed the presence of saturated hydrocarbon.

View
Thumbnail Image
Publication

The effect of different khaya senegalensis raw feedstock particle sizes on solid fuel pellet quality

2020-07-09 , Ras Izzati Ismail , Usamah M.I. , Abd Razak Shaari , Yee K.C. , Alina Rahayu Mohamed , Mohd Riduan Jamalludin , Norawanis Abdul Razak , Leng L.Y. , Nur Lailina Makhtar , Rosli M.U.M.

In recent years, the usage and demand for biomass pellet has been increasing due to the need of substitution for non-renewable energy source. Therefore, high quality solid fuel is in need to cater this demand. Pellet qualities such as durability, calorific value and density are different depending on the type of material, size of particle and the density of the feedstock. In this study, the durability, calorific value and unit density of Khaya Senegalensis pellet was investigated. This was done to identify the optimum particle size to obtain the best qualities of pellet possible. The ground biomass material was separated into 0.15 mm, 0.50 mm and 1.00 mm particle sizes, pelletized and ultimately the pellet durability, calorific value and unit density were tested in this study. It was found that 0.15 mm particle size resulted in the highest pellet durability, and density value. 1.00 mm particle size pellet has the highest calorific value. As a conclusion, different raw biomass feedstock particle size will affect the durability, density and calorific value of pellet.

View
No Thumbnail Available
Publication

Direct oxidation of Hibiscus annabinus stalks to vanillin using CeO₂ nanostructure catalysts

2023 , Anita Ramli , Nur Akila Syakida Idayu Khairul Anuar , Nur Aielia Amira Bakhtiar , Normawati Mohamad Yunus , Alina Rahayu Mohamed

Biomass lignin can be used to produce vanillin through an oxidation process. Although its purity is high, the processing time and separation efficiency are not ideal. This research aims to produce vanillin directly from Kenaf stalks without separating the lignin first from the lignocellulosic biomass. This method is greener because it does not require the separation of cellulose and hemicellulose from the biomass, thus minimizing the use of acid and alkaline solutions and saving time. A high oxygen storage capacity and release capacity of ceria as an oxidation catalyst contribute to the reversable redox properties between Ce⁴⁺ and Ce³⁺ in ceria lattice. Cerium oxide nanostructures were synthesized using a hydrothermal method treated under alkaline NaOH, followed by drying at 120 °C for 16 h and calcining at different temperatures between 400 and 600 °C for the direct oxidation of Kenaf stalks to vanillin under microwave irradiation. The catalysts were characterized for their physicochemical properties using XRD, N2 adsorption–desorption isotherms and TEM. All synthesized CeO₂ nanostructures showed the presence of diffraction peaks assigned to the presence of cubic fluorite. The N2 adsorption–desorption isotherms showed that all catalysts possess a Type IV isotherm, indicating a mesoporous structure. The TEM image shows the uniform shape of the CeO₂ nanostructures, while HRTEM images show that the CeO₂ nanostructures are single-crystalline in nature. All catalysts were tested for the direct oxidation of Kenaf stalks using H₂O₂ as the oxidizing agent in temperatures ranging from 160 to 180 °C for 10–30 min with 0.1–0.3 g catalyst loading under 100–500 W of microwave irradiation. The CeO₂-Nps-400 catalyst produced the highest vanillin yields of 3.84% and 4.32% for the direct oxidation of Kenaf stalks and extraction of lignin from Kenaf stalks, respectively. Compared to our earlier study, the highest vanillin yields of 2.90% and 3.70% for direct biomass and extracted lignin were achieved using a Ce/MgO catalyst.

View
Thumbnail Image
Publication

Cracking the code: process parameter effects on Khaya senegalensis energy pellet moisture content

2023-12 , Ras Izzati Ismail , Khor Chu Yee , Alina Rahayu Mohamed

The production of energy pellets from biomass sources holds immense potential for sustainable renewable energy generation. This study investigates the influence of key process parameters on the moisture content of energy pellets derived from Khaya senegalensis, a promising biomass feedstock in Malaysia. With a focus on unlocking the relationship between process variables and pellet moisture, a systematic experimental approach was adopted. The objective of this study is to investigate the effects of raw material moisture, feedstock particle size, compression pressure, and pelletization temperature on the manufactured biomass energy pellet's moisture content. By employing a comprehensive design of experiments and statistical analysis, the nuanced effects of these parameters are revealed on the moisture content of Khaya senegalensis energy pellets. The results illuminate the complex interplay between these process variables and the final moisture characteristics of the pellets. Understanding how these parameters impact moisture content is crucial for optimizing pellet quality, combustion efficiency, and storage stability. The study found a quadratic relationship between particle size, compression pressure, and pelletization temperature, indicating that larger particle sizes correlate with higher moisture content. Excessive pressure led to elevated levels while increasing temperature showed a decreasing trend. This research contributes valuable insights that advance the knowledge frontier of biomass pelletization, paving the way for enhanced utilization of Khaya senegalensis as a renewable energy resource.

View
Thumbnail Image
Publication

Botanical insecticide of chili and ginger extract on Nilaparvata lugens, brown planthopper

2020 , Noor Hasyierah Mohd Salleh , Norhidayah Abd Aziz , Alina Rahayu Mohamed , Adilah Anuar , I Nur Humaira

Invasion of Nilaparvata lugens or brown planthopper (BPH) in paddy fields has led to the use of excessive chemical insecticides due to its effectiveness. However, excessive applications has contributed several negative effects on the environment, farmers as well as non-targeting organisms. As an alternative, a mixture of a botanical insecticide containing mixture of chili and ginger extracts have been studied. Three parameters were studied namely the extract concentration, time of exposure and temperature of exposure. The results showed that 90% of BPH mortality was found at 40% extract concentration with 72 hr duration time of exposure at optimal temperature 30 C. HPLC analysis proved the presence of capsaicin and gingerol at peaks of 4.502 min and 11.046 min respectively. From repellency analysis, the BPH showed selective repel action against the treated paddy. This is due to the pungent odor contributed from compound of gingerol, shogaol and capsaicin presented in the mixture. Meanwhile, contact toxicity studies have successfully give 100% of mortality of BPH. Microscopic analysis have shown BPH deformities was increased by the extract concentration.

View