Razi Ahmad
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Preferred name
Razi Ahmad
Official Name
Razi, Ahmad
Alternative Name
Ahmad, Razi
Ahmad, R. B.
Ahmad, R.
Ahmad, R. Badlishah
Main Affiliation
Scopus Author ID
54419444500
Researcher ID
B-9254-2012

Research Output
Now showing 1 - 3 of 3
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Publication

Optimization studies of coal organic sulfur removal using Potassium Carbonate and Ethylene Glycol as a deep eutectic solvent

2023-06-29 , Syarifah Nursyimi Azlina Syed Ismail , Mohd Azlan Mohd Ishak , Khudzir Ismail , Wan Izhan Nawawi , Nur Nasulhah Kasim , Asnida Yanti Ani , Azil Bahari Alias , Razi Ahmad

Combustion of coal emits sulfur dioxide gas into the atmosphere. When reacting with water vapour, this gas produces sulfuric acid, also known as acid rain, causing environmental destruction, and endangering human health. One option to address these issues is to remove the sulfur from coal before combustion. Physical and chemical pre-treatments using oxidizing or reducing agents easily remove inorganic sulfur from coal, namely pyrite and sulfate sulfur. However, organic sulfur is hard to remove unless a particular reagent is applied to break the carbon-sulfur bonds to release the sulfur from the coal matrix. This study reports the utilization of a mixture of potassium carbonate and ethylene glycol (K2CO3:EG) under sonication to extract organic sulfur from coal. The ultrasonic shockwave separates sulfur from the coal's macromolecular structure by breaking the chemical connections that hold sulfur to coal. CCD-RSM experimental design was presented to overcome traditional methods that make finding the optimal standard difficult and time-consuming. The effects of molar ratio, temperature, and extraction time on the removal of organic sulfur in coal were investigated, and sonicating coal at 40 °C for 60 minutes with 1:16 K2CO3:EG was found to be the ideal parameter. The changes to the thiophene and organic sulfate FTIR peaks may serve as a preliminary measure of the effectiveness of K2CO3:EG in coal desulfurization. This research shows that solvent-pre-treated coal may be safe and environmentally advantageous, two goals of the 2030 Agenda for Sustainable Development.

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Effect on product Yield and Tar composition through co-gasification of pretreated palm kernel shell and Mukah Balingian coal

2020 , Razi Ahmad , Mohd Azlan Mohd Ishak , Nur Nasulhah Kasim , Khudzir Ismail

In this study, co-gasification of palm kernel shell (PKS) and Mukah Balingian (MB) coal was carried out in a fixed bed reactor. The effect of sample pretreatment of both samples were explored via co-gasification towards product yields and tar composition. Results indicated that, pretreated blending samples produced higher gas yield with lower tar and char yield than the untreated blending samples. This was due to low moisture and oxygenated components of the pretreated samples prior to co-gasification. The tar composition of the pretreated blending samples showed increasing in the aromatic and aliphatic alkane, whereas, noticeable decreasing of phenol and carbonyl. Thus, pretreated of PKS and MB coal have prominence influence on the distribution of product yields and tar composition through co-gasification.

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Desulfurization and optimization of high sulfur Jambi province coal by ultrasonic-assisted process using Peroxyacetic Acid (PAA) treatment

2025-06 , Razi Ahmad , Nurul Fatihah Nazua , Syarifah Nursyimi Azlina Syed Ismail , Mohd Fauzi Abdullah , Mohd Azlan Mohd Ishak , Wan Izhan Nawawi Wan Ismail , Khudzir Ismail , Muslim Darbi Abdulrrahman

The desulfurization process of high-sulfur coal from Jambi Province, Indonesia was investigated using peroxyacetic acid (PAA) as mild oxidising agent by ultrasonic wave. This study reports the utilization of a mixture of acetic acid and 6% hydrogen peroxide (CH3COOH: H2COOH) under sonication to extract organic sulfur from coal. The ultrasonic shockwave separates sulfur from the coal's macromolecular structure by breaking the chemical connections that hold sulfur to coal. The optimum concentration, temperature, and processing time for the coal desulfurization process were determined using the Central Composite Design-Response Surface Methodology (CCD-RSM) to overcome the traditional methods that make finding the optimal standard difficult and time-consuming. Sonicating coal at 30 ËšC for 30 minutes with 70:30 (CH3COOH: H2COOH) was found to be the ideal parameter. Results shows that all inorganic and some of the organic sulfur could be removed from the coal using mild conditions without severely affecting the coal microstructure as observed in the FESEM-EDX. Through the FTIR analysis, the organic sulfur structural parameters show the relative abundance of aliphatic sulfur (thiol, thiophene and sulfone) and organic matters in these coals decreased after the coal treated by PAA.To clarify its chemical effect, the production regularities of hydroxyl radical under ultrasonic field was determined using the iodine release method. Experimental results also showed that the production rule of hydroxyl radical was consistent with the desulfurization degree. These findings confirmed that the synergistic action of physical and chemical effects of the ultrasonic played an important role in this desulfurization process, which could serve as a reference for further optimizing the coal desulfurization process.

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