Coffee Husk Briquettes: A New Renewable Energy Source

hindawi,Advances in Materials Science and Engineering, 2022

Biomass energy accounts for more than 92 percent of overall energy consumption in Ethiopia. As a result, Ethiopia is one of the world's most biomass-dependent countries. e high reliance on wood fuels and agricultural residues for fuel harms society's social, economic, and environmental well-being. is study aims to create and test the quality of fuel briquettes made from the coffee husk. Also built and produced are a carboniser/charcoal kiln, a manually operated molder system, and a briquette stove for burning the manufactured briquette. e carboniser converts 15 kg of raw coffee husk into 6 kg of carbonised char in 25 minutes, and the manually operated briquette molder can press 30 kg per hour. e efficiency of converting raw coffee husk into carbonised char content was 40.12%. In the geological survey of Ethiopia, the geochemical laboratory directorate received triplicate samples of the fuel briquette charcoal for analysis. Moisture content, fixed carbon content, ash content, sulfur content, and calorific value were determined using a bomb calorimeter and a ceramic lining furnace. Physical properties of fuel briquettes ranged from 10.03% moisture content, 970 kg/m 3 density, 81% fixed carbon, 5.15% ash content, 0% sulfur, and 30.54 Kcal/kg higher heating value, according to laboratory results. e results of the study revealed that the coffee husk fuel briquettes produced have more positive characteristics. Fuel briquettes were cost-effective and environmentally friendly and reduced deforestation compared to firewood. is study clearly shows that briquettes made from coffee husk could be used as an alternative energy source when this kind of waste is well managed.

Irish Interdisciplinary Journal of Science & Research

░ 1. Introduction Desertification is one of the world's biggest problems due to environmental changes and human abuse of forest resources as fuel and building materials (Abakr and Abasaeed, 2006). Most of our nation's urban and rural population, which is rapidly growing, considers forests to be their principal source of fuel. Even though living standards and fashions have changed significantly, particularly in metropolitan areas, traditional cooking practices still predominate. Due to the availability and affordability of wood (most people now collect wood from the neighboring forests for free), it is still the preferred fuel for the majority of local cuisine. This reliance on wood fuel contributes greatly to the nation's declining forest cover and is linked to the unfavorable changes in weather patterns and resulting climate variability that the nation is currently experiencing [2]. Due to the decreased ability for carbon absorption, this overreliance on wood fuel is a major contributor to the loss of biodiversity, declining tree cover, and worsening effects of global warming [3]. Since 30 to 50 percent of the weight of coffee fruit is wasted, the coffee manufacturing business generates enormous amounts of byproducts. Numerous reused solutions have been suggested as a result of the enormous seed production of coffee. Nevertheless, to manage the significant volume of coffee husk, a win-win solution is vital [4]. Coffee husks are regarded as an economically worthless by-product in East Africa, particularly in portions of Ethiopia, and are thrown out in fields and waterways with little use or care. This method of disposing of coffee husks wastes biomass energy and land resources and has a negative impact on the quality of the soil and water. While the planting area expanded from 407,147 ha to 700,475 ha between 2007 and 2016, the yearly production of coffee increased from 273,400 tonnes (t) to 469,091 t. As more processed coffee cherries were produced, the amount A B S T R A C T Conventional methods for burning coffee husk biomass directly result in high levels of air pollution and very low thermal efficiency. These issues are alleviated, transportation and storage expenses are decreased, and energy production is improved by raising their net calorific values per unit when they are turned into briquettes. Minimizing the impact of coffee by-product constitutes and turning them into an income generation source for the local communities through the development of biomass briquette machines. The experiment used different ratios of carbonized coffee husk and Clay Soil as a binder. The capacity of the machine, Physical and mechanical properties and thermal characteristics of the briquettes were evaluated. Throughput capacity and Degree of Densification of the machine, bulk Density, Resistance to water penetration, Shatter, and Tumbling resistance of the Briquette were increasing with the increase of clay binder ratio with a significant difference at alpha 0.05. The average minimum and maximum throughput capacity and Degree of Densification of the machine were 1.117 and 1.273 kg/min and 290.4 and 308.7%, respectively, at 0 and 25% clay binder ratios. Increasing the clay soil binder ratio increases the percentage of Ash content but decreases the fixed carbon percent and Calorific value. The minimum and maximum Calorific values, Fixed carbon, and Ash content were 3856.89 cal/g, 12.5%, 24%, and 5001.78 cal/g, 30%, and 36%, respectively. Both ignition and water boiling time increase by the increase of clay soil binder ratio with a minimum of 6.5 and 14.3 minutes and a maximum of 7.6 and 18.5 minutes, respectively. It was discovered that clay was the best binding medium for coffee husk, with a clay content of 5% having the best calorific value of 4848.39 Cal/g and the least amount of ash.

Several torrefaction experiments using wood briquettes are reported in this paper. The torrefied briquettes weight yield lies between 43 and 94 %, and energy yields ranged from 50 to 97 % depending on the operating parameters. After torrefaction the briquettes showed an increase of approximately 15 % in heating value, and a decrease of approximately 73 % in equilibrium moisture. It was shown that torrefied briquettes achieved hydrophobic character and remained unaffected when immersed in water. This research also provides information on proximate and elemental analysis , showing that temperature has more influence than residence time. The aforementioned data indicate that torrefaction is a feasible alternative to improve energy properties of ordinary briquettes and prevent moisture absorption during storage.

Coffee is regarded as the highly consumed beverage throughout the world and has established a key spot in the world economy as an important commodity for trading. In general, they are produced by brewing their roasted and ground beans, which release aromatic coffee; as well as produce an equivalent amount of spent coffee grounds (SCG). Previously, they were discarded as wastes or used as natural pest repellent or garden fertilizer; however, in recent times, are valorized into biofuels owing to their high calorific value. In fact, SCG briquettes have gained wide attention for supplying energy renewably, especially to the rising energy demand; and also have been identified as an effective measure to reduce their pollution. With this in mind, this present chapter focuses on reviewing the availability and chemistry involved in these SCG wastes, pre-treatments and preparations required for their briquetting, compacting techniques followed, and fuel characteristics of their briquettes, fr...

Ciência e Agrotecnologia, 2013

The use of biomass has been recognized as a potential renewable energy and an alternative substitute that contributes to the decrease of fossil fuels consumption. Therefore, this research aimed to analyze the thermal behavior of briquettes made of residues from coffee grain processing in different conditions: in natura, torrefied and carbonized. Eucalyptus sawdust was used for comparison. The briquettes were carbonized considering final temperature of 450º C (kept for 30 min). The briquettes torrefaction was performed in an electric oven (muffle) using two heating rates until 250º C (kept 60 min). The thermal-gravimetric analysis was made in nitrogen atmosphere until the temperature of 600º C. The contents of fixed carbon and volatile matter of the fuels were determined. The carbonized briquette of residues from coffee grain processing presented higher stability and low thermal decomposition. It was observed a low influence of torrefaction heating rate under thermal properties of briquettes, and fixed carbon and volatile matter content. Regarding the raw biomass, lower total mass loss was observed for the residues from coffee grain processing when compared to Eucalyptus sawdust. The carbonized and torrefied briquettes presented higher hydrophobicity than raw briquettes.

2015

Some residues from industries and households were used to turn into briquettes. In this research, waste paper and coffee residues could be practically used to produce fuel briquettes by adding starch as a binder before performing a molding cold process. The optimal ratios between waste paper and coffee residue were considered to be 70:30, 60:40, 50:50, 40:60, and 30:70.Their calorific values ranged from 3,708.5 to 4,347.1 cal/g. These values were almost equivalent to the amount of the heat from the firewood. The study also discovered that the briquettes rendered their moisture content (7-9%), the amount of ash (3.8-8.5%), and the amounts of fuel elements (45.56% carbon, 6.48% hydrogen, 45.41% oxygen, 0.75% nitrogen, and 0.08% sulfur) within the acceptable values of biomass standards. The briquettes were readily molded, not easily shattered, and inflammable with low amount of smoke and odor. Therefore, the production of fuel briquettes from waste paper and coffee residue could be one of the viable alternatives for community energy generation.

Ecological Engineering & Environmental Technology, 2023

One of the fuels made from biomass are Charcoal briquettes. The biomass used in this study was coffee husk and coffee wood. This study aims to find out the ratio of coffee husk and coffee wood that accordance the briquette standards of the Minister of Energy and Mineral Resources (ESDM) and (Indonesian Nasional Standard) SNI 01-6235-2000. In this research, a comparison was made between coffee fruit skin charcoal and coffee wood charcoal with a ratio of 100:0 (KK 1), 75:25 (KK 2), 50:50 (KK 3), 25:75 (KK 4), 0:100 (KK 5). The resulting briquettes were tested for their proximate value using a furnace, for the calorific value they were tested using a boom calorimeter. Apart from that, a combustion rate test was also carried out by burning briquettes in a combustion furnace. The results of the analysis of proximate obtained were water content of the briquettes ranging from 3.39-5.91%, all of which in accordance with SNI and also which in accordance with the regulation of ESDM, the ash content that which in accordance with SNI was KK 4 and KK 5 , namely 6.71% respectively. and 6.47% and those that comply with the ESDM Ministerial Regulation are KK 3 , KK 4 and KK 5 with ash content values of 9.62%, 6.71% and 6.47% respectively. Meanwhile, the volatile matter value ranges from 32.31-35.59%, not yet accordance with SNI. for fixed carbon values ranging from 50.1-54.55%, this also does not accordance with SNI. However, for the calorific value of 4536-6723 Cal/g, all of them meet the ESDM Ministerial Regulation, and those that accordance with SNI is KK 2 , KK 3 , KK 4 and KK 5 with calorific values of 5650, 5821, 5866 and 6723 Cal/g respectively. Meanwhile, the combustion rate ranges from 0.341 to 0.711 g/min. Coffee husk waste combined with coffee wood has the potential to be used as fuel briquettes where the KK 4 composition has water content, ash content and calorific value that meets SNI and ESDM regulations, even though the volatile matter and fixed carbon values do not yet meet.

Applied Engineering in Agriculture, 2018

A semi-mobile torrefaction and densification pilot plant was constructed in order to determine ideal operating conditions and evaluate briquette quality and throughput rate using forest residuals as the input feedstock. Experiments were conducted at various conditions with feedstock moisture content ranging from 4% to 25% (wet basis), reactor residence times of 10 and 20 min, and final product temperatures between 214°C and 324°C. Optimal operating conditions, evaluated based on throughput rate, specific electricity demand, torrefied briquette grindability, briquette volumetric energy density, and briquette durability, were identified to occur with a short residence time (10 min), low feedstock moisture content (<11% wet basis), and high final product temperature between 267°C and 275°C. These conditions were able to process 510 to 680 kg h-1 (wet basis) feedstock with a dry mass yield of 79% to 84% to produce torrefied biomass with a higher heating value of 21.2 to 23.0 MJ kg-1 (dry basis) compared to 19.6 MJ kg-1 for the original biomass. Torrefied briquettes produced at these conditions had a neatly stacked packing density of 990 kg m-3 and a volumetric energy density of 21,800 MJ m-3. Their specific grinding energy was an average 37% of the energy required to grind a raw biomass briquette. These torrefied briquettes were more durable (94% DU) than raw briquettes (85% DU) directly following production, but were less durable after undergoing temperature and humidity fluctuations associated with long distance transportation (74% DU for torrefied and 84% DU for raw biomass briquettes). Results from this pilot plant are promising for commercial scale production of high quality torrefied briquettes and should lead to additional research and development of a torrefaction system optimized for a higher throughput rate at these conditions.

Energies

The present study investigates the quality changes of wood bio-briquette fuel after the addition of spent coffee ground (SCG) into the initial feedstock materials (sawdust, shavings) in different mass ratios (1:1, 1:3). Analysis of SCGs fuel parameter proved great potential for energy generation by a process of direct combustion. Namely, level of calorific value (GCV = 21.58 MJ∙kg−1), of ash content (Ac = 1.49%) and elementary composition (C = 55.49%, H = 7.07%, N = 2.38%, O = 33.41%) supports such statement. A comparison with results of initial feedstock materials exhibited better results of SCG in case of its calorific value and elementary composition. Bulk density ρ (kg·m−3) and mechanical durability DU (%) of bio-briquette samples from initial feedstock materials were following for sawdust: ρ = 1026.39 kg·m−3, DU = 98.44% and shavings: ρ = 1036.53 kg·m−3, DU = 96.70%. The level of such mechanical quality indicators changed after the addition of SCG. Specifically, SCG+sawdust mix...