scholarly journals A Comparative Study on Thermochemical Valorization Routes for Spent Coffee Grounds

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3840
Author(s):  
Jie Yang ◽  
Hao Chen ◽  
Haibo Niu ◽  
Josiah McNutt ◽  
Quan He
Keyword(s):  
Oil Extraction ◽  
Hydrothermal Liquefaction ◽  
Biodiesel Production ◽  
Optimal Conditions ◽  
Spent Coffee Grounds ◽  
Microwave Assisted ◽  
Assisted Extraction ◽  
Coffee Grounds ◽  
Biodiesel Synthesis ◽  
Biochemical Compositions

Extracting oil from spent coffee grounds (SCG) for biodiesel production has recently attracted much research interest. Large amounts of organic solvents are involved for oil extraction and biodiesel synthesis. Hydrothermal liquefaction (HTL) is an emerging thermochemical technology with great potential for biocrude production from a broad range of feedstocks. This study attempted to compare two SCG valorization options: route 1, oil extraction for biodiesel production followed by HTL of defatted SCG; and route 2, direct HTL of raw SCG. The microwave-assisted extraction conditions were optimized to effectively remove oil from SCG using response surface methodology. Under optimal conditions, an SCG oil yield of 8.4 wt.% could be achieved. HTL of defatted SCG generated less biocrude (18.9 wt.%) than that of raw SCG (28.1 wt.%). The biochemical compositions of resultant biocrudes were largely different from each other. The life cycle assessment was conducted on each of the SCG valorization routes and showed that the greenhouse gas emissions from direct HTL of raw SCG were only 35% of the other valorization route, suggesting that direct HTL is a favorable valorization route for SCG within this study’s scope.

scholarly journals Biodiesel Production from Spent Coffee Grounds

2017 ◽  
Vol 25 (40) ◽  
pp. 113-121 ◽  
Author(s):  
Lenka Blinová ◽  
Alica Bartošová ◽  
Maroš Sirotiak
Keyword(s):  
Organic Solvents ◽  
Oil Extraction ◽  
Waste Material ◽  
Biodiesel Production ◽  
Spent Coffee Grounds ◽  
Drying Oil ◽  
Biodiesel Feedstock ◽  
Coffee Grounds ◽  
Coffee Oil

Abstract The residue after brewing the spent coffee grounds is an oil-containing waste material having a potential of being used as biodiesel feedstock. Biodiesel production from the waste coffee grounds oil involves collection and transportation of coffee residue, drying, oil extraction, and finally production of biodiesel. Different methods of oil extraction with organic solvents under different conditions show significant differences in the extraction yields. In the manufacturing of biodiesel from coffee oil, the level of reaction completion strongly depends on the quality of the feedstock oil. This paper presents an overview of oil extraction and a method of biodiesel production from spent coffee grounds.

scholarly journals Microwave-Assisted Extraction of Phenolic Compounds from Spent Coffee Grounds. Process Optimization Applying Design of Experiments

Molecules ◽  
2021 ◽  
Vol 26 (23) ◽  
pp. 7320
Author(s):  
José P. Coelho ◽  
Maria P. Robalo ◽  
Stanislava Boyadzhieva ◽  
Roumiana P. Stateva
Keyword(s):  
Phenolic Compounds ◽  
Design Of Experiments ◽  
Process Optimization ◽  
Dominant Factor ◽  
Assay Method ◽  
Microwave Assisted Extraction ◽  
Spent Coffee Grounds ◽  
Microwave Assisted ◽  
Assisted Extraction ◽  
Coffee Grounds

In this study, sustainable technology microwave-assisted extraction (MAE) in association with green solvents was applied to recover phenolic compounds from spent coffee grounds (SCGs). A design of experiments (DOE) was used for process optimization. Initially, a 24−1 two level Fractional Factorial Design was used and ratios “solvent to solute” and “ethanol to water” were identified as the significant experimental factors. Consequently, Central Composite Design (CCD) was applied to analyze the effects of the significant variables on the response yield, total polyphenols content (TPC), and antioxidant activity (AA) by the DPPH assay method, and quadratic surfaces to optimize those responses were generated. The values of the significant factors of 16.7 (solvent/solute) and 68.9% (ethanol/water) were optimized simultaneously the yield (%) at 6.98 ± 0.27, TPC (mg GAE/g) at 117.7 ± 6.1, and AA (µmol TE/g) at 143.8 ± 8.6 and were in excellent agreement with those predicted from the CCD model. The variations of the compositions of the lipids, caffeine, pentacyclic diterpenes, and FAME as a function of the dominant factor % ethanol in the solvent mixture were analyzed by applying NMR and GC-FID, and the results obtained confirmed their determinative significance.

scholarly journals Optimization of Ultrasound-Assisted Extraction of Spent Coffee Grounds Oil Using Response Surface Methodology

Processes ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 2085
Author(s):  
Malek Miladi ◽  
António A. Martins ◽  
Teresa M. Mata ◽  
Miguel Vegara ◽  
María Pérez-Infantes ◽  
...  
Keyword(s):  
Health And Safety ◽  
Oil Extraction ◽  
Extraction Yield ◽  
Operating Conditions ◽  
Extraction Time ◽  
Spent Coffee Grounds ◽  
Ultrasound Assisted Extraction ◽  
Assisted Extraction ◽  
Coffee Grounds ◽  
Ultrasound Assisted

Spent coffee grounds (SCGs) generated in coffee processing for beverages and other products are a very significant organic residue that needs to be properly treated. Waste valorization via oil extraction has the potential to obtain compounds that can be used for producing biodiesel or other high-value products, such as polymers. This work focuses on the ultrasound-assisted extraction of SCG oil using n-hexane as a solvent. Three key process parameters are analyzed: temperature, extraction time, and liquid/solid (L/S) rate of solvent, using a central composite rotatable design (CCRD), an analysis that, to the author’s knowledge, is not yet available in the literature. The data were analyzed using the software StatSoft STATISTICA 13.1 (TIBCO Software Inc., Palo Alto, CA, USA). Results show that all parameters have a statistical influence on the process performance (p < 0.05), being the L/S ratio the most significant, followed by extraction time and temperature. An analysis of variance (ANOVA) showed that the empirical model is a good fit to the experimental data at a 95% confidence level. For the range of conditions considered in this work, the optimal operating conditions for obtaining an oil extraction yield in the range of 12 to 13%wt are a solvent L/S ratio of around 16 mL g−1, for a temperature in the range of 50 to 60 °C, and the longest contact time, limited by the process economics and health and safety issues and also, by the n-hexane boiling temperature.

scholarly journals A Comprehensive Review on Oil Extraction and Biodiesel Production Technologies

2021 ◽  
Vol 13 (2) ◽  
pp. 788
Author(s):  
Zulqarnain ◽  
Muhammad Ayoub ◽  
Mohd Hizami Mohd Yusoff ◽  
Muhammad Hamza Nazir ◽  
Imtisal Zahid ◽  
...  
Keyword(s):  
Energy Demand ◽  
Alternative Fuels ◽  
Fossil Fuels ◽  
Significant Proportion ◽  
Waste Cooking Oil ◽  
Oil Extraction ◽  
Biodiesel Production ◽  
Waste Oils ◽  
Biodiesel Synthesis ◽  
Production Technologies

Dependence on fossil fuels for meeting the growing energy demand is damaging the world’s environment. There is a dire need to look for alternative fuels that are less potent to greenhouse gas emissions. Biofuels offer several advantages with less harmful effects on the environment. Biodiesel is synthesized from the organic wastes produced extensively like edible, non-edible, microbial, and waste oils. This study reviews the feasibility of the state-of-the-art feedstocks for sustainable biodiesel synthesis such as availability, and capacity to cover a significant proportion of fossil fuels. Biodiesel synthesized from oil crops, vegetable oils, and animal fats are the potential renewable carbon-neutral substitute to petroleum fuels. This study concludes that waste oils with higher oil content including waste cooking oil, waste palm oil, and algal oil are the most favorable feedstocks. The comparison of biodiesel production and parametric analysis is done critically, which is necessary to come up with the most appropriate feedstock for biodiesel synthesis. Since the critical comparison of feedstocks along with oil extraction and biodiesel production technologies has never been done before, this will help to direct future researchers to use more sustainable feedstocks for biodiesel synthesis. This study concluded that the use of third-generation feedstocks (wastes) is the most appropriate way for sustainable biodiesel production. The use of innovative costless oil extraction technologies including supercritical and microwave-assisted transesterification method is recommended for oil extraction.

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