Thermal and Mechanical Quality Analysis of Briquettes of Arabica Coffee and Rice Husk Composites as an Alternative Bio-fuel

Oct 28, 2026

Coal remains a dominant energy source for fuel and electricity, yet it is a major driver of global carbon emissions. To lessen coal dependence in fuel briquettes, this study evaluates biomass composite briquettes produced from rice husk (RH) and coffee husk (CH). The work analyzes thermal and mechanical properties while varying raw particle sizes, using a 25:75 wt/wt CH:RH blend and mesh sizes 60, 80, and 100 after carbonization at 400 °C for 60 min.

LanguageEnglish

CategoryResearch & Report

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Pages6

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1. Introduction

Diamond Open Access 􀀸 | Article Bioengineering/Material Science and Engineering
Thermal and Mechanical Quality Analysis of Briquettes of Arabica Coffee and Rice Husk Composites as an Alternative Bio-fuel
Indri Winarti, Rizky Safarina, Ryan Nur Iman, Asti Sawitri, Ridwan Ramdani, and HasniahAliah*

Cite [https://doi.org/](https://doi.org/)􀀱􀀰.􀀶􀀴􀀵􀀸􀀹/juri/􀀲􀀰􀀹􀀷􀀳􀀵
Submitted: May 􀀲􀀵, 􀀲􀀰􀀲􀀵 Revised: August 􀀳, 􀀲􀀰􀀲􀀵 Accepted: November 􀀱􀀸, 􀀲􀀰􀀲􀀵 | | | --- | --- | | ABSTRACT
Coal remains a primary energy source for fuel and electricity generation; however, it is a major contributor to global carbon emissions. Therefore, researchers are exploring strategies to reduce coal usage in fuel briquettes. A promising alternative is biomass-based briquettes, which offer similar performance to traditional charcoal while being more sustainable. This study investigated the thermal and mechanical properties of briquettes made from rice husk (RH) and coffee husk (CH), focusing on how the particle sizes of the raw materials affect the heating value. RH and CH are rich in lignin, cellulose, and hemicellulose, which are crucial for briquette structure, whereas tapioca flour, used as a binder, provides amylose and amylopectin to enhance bonding. Carbonization was performed at 400 °C for 60 min. A 25:75 (wt/wt%) CH: RH blend was used and three mesh sizes (60, 80, and 100) were evaluated by thermal and mechanical characterizations. The briquettes were assessed on the basis of their calorific value, moisture content, shatter index, volatile matter, fixed carbon content, density, ash content, and combustion rate. The 149 µm (100 mesh) sample had the highest density (662.81 kg/m3), moisture content (6.7%), volatile-matter content (7.07%), and burning rate (0.39 gr/min). In contrast, the 250 µm (60 mesh) sample had the highest ash content (5.01%) and the lowest fixed carbon content (82.04%) and shatter index (4.36%). These findings indicate that controlling the particle size of rice husk and coffee husk can improve the performance of biomass composite briquettes, highlighting their potential as a sustainable alternative to coal for domestic use and small-scale energy applications. | | | Keywords: rice husk, carbonization, briquettes, coffee husk, mesh | | | 􀀱 . INTRODUCTION
Coal remains a primary energy source and is commonly utilized for fuel and electricity production 1 . The combustion of fuel coal emits substantial quantities of CO2 and other pollutants, resulting in local air pollution and contributing to global atmospheric CO2 2,3 . To reduce these environmental impacts, researchers are exploring ways to minimize coal usage in briquettes by developing biomass-based briquettes offer comparable quality to traditional charcoal briquettes 4–8 .
The quality, i.e., strength and durability, of briquettes is determined by the raw materials, material composition, particle size, level of compaction, and binder used during briquette molding 9, 10 . Another method for improving briquette quality is to use additives to improve their physical, mechanical, and thermal properties 11 . The addition of biomass can enhance the calorific value per unit volume, improve particle size consistency, and boost overall quality 9 .
Coffee husk (CH) and rice husk (RH) are currently underutilized biomass resources with the significant potential. CH is the dry outer shell of coffee cherries discarded during processing, while RH is the hard-protective layer removed from rice grains during milling. In particular, one hectare of coffee plantation can | generate approximately 1.8 tons of CH waste. Currently, this byproduct is primarily used as an organic fertilizer without further processing to maximize its potential. CHis advantageous because of its high calorific value, substantial moisture content (75–80%), and low sulfur content. In their raw form, CH typically contains 2.2% moisture, 0.73% ash, 74.20% volatile matter, 25.07% fixed carbon, and is composed

FAQs

What is the main goal of the study?

To investigate how particle size influences the thermal and mechanical properties of CH/RH composite briquettes as an alternative to coal-based fuel.

Which briquette formulations and preparation conditions were used?

Briquettes used a 25:75 (wt/wt) CH:RH blend and were carbonized at 400 °C for 60 minutes, then tested across three mesh sizes (60, 80, 100).

How were the briquettes evaluated?

They were assessed using calorific value, moisture content, shatter index, volatile matter, fixed carbon content, density, ash content, and combustion rate.

Oct 28, 2026

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