This page has only limited features, please log in for full access.

Unclaimed
Alla Alrefai
School of Mechanical & Manufacturing Engineering, Dublin City University, 9 Dublin, Ireland

Basic Info

Basic Info is private.

Honors and Awards

The user has no records in this section


Career Timeline

The user has no records in this section.


Short Biography

The user biography is not available.
Following
Followers
Co Authors
The list of users this user is following is empty.
Following: 0 users

Feed

Journal article
Published: 09 August 2021 in Energies
Reads 0
Downloads 0

Dates are an important food source in many countries that produce different types of dates. Dates have a significant amount of waste, either from planting or eating them. A large amount of seeds are produced from eating it. This study is considered to explore the quantity and the quality of biogas produced from the Sagai date seeds through the anaerobic digestion process (AD) before and after oil extraction and exploitation of oil in biodiesel production. In addition, the study aims to tests the resulted digestate from the AD process. This test was performed to ensure that the digestate contains the three basics elements (N, P and K) to be used in agriculture. In its preparation, the date seeds were ground after washing via a grinding machine without exposure to any other treatment process. Design of Experiments (DOE) was applied in determining the effect of temperature, volatile solid and sludge quantity on the resulted biogas. The energy balance at the optimum results was calculated. The highest biogas volumes from the AD of date seed before and after oil extraction were 4140 cc and 3534 cc, respectively, at 37 °C, 4.2 g-VS and 50% sludge quantity. While the highest methane/g-VS were 1143.8 cc/g-VS and 949.6 cc/g-VS, respectively, at 37 °C, 1.1 g-VS and 50% sludge quantity. The oil obtained using the Soxhlet method at 70 °C, 1:4 ratio of date seeds to n-hexane solvent and 5 h reaction time was 16% of the date seed mass (79% biodiesel and 9% glycerine). Therefore, the resultant effect from the main findings indicated that the study supports the investigation of the possibility of exploiting date seeds in the production of biogas, biodiesel and bio-fertiliser.

ACS Style

Alla Alrefai; Raid Alrefai; Khaled Benyounis; Joseph Stokes. Biogas Produced by Anaerobic Digestion Process and Biodiesel from Date Seeds. Energies 2021, 14, 4851 .

AMA Style

Alla Alrefai, Raid Alrefai, Khaled Benyounis, Joseph Stokes. Biogas Produced by Anaerobic Digestion Process and Biodiesel from Date Seeds. Energies. 2021; 14 (16):4851.

Chicago/Turabian Style

Alla Alrefai; Raid Alrefai; Khaled Benyounis; Joseph Stokes. 2021. "Biogas Produced by Anaerobic Digestion Process and Biodiesel from Date Seeds." Energies 14, no. 16: 4851.

Journal article
Published: 17 December 2020 in Energies
Reads 0
Downloads 0

A significant expansion of anaerobic digestion (AD) processes would certainly result in a reduction in the current dependence on fossil fuels. The operational costs, the large amounts of digestate generated and the expenses of dealing with it and the volatility of the fuel indexes represent major environmental and economical challenges to the diffusion of AD. Increasing the bio-products of AD could possibly help in increasing its profitability and limit these challenges. This study investigates the influence of mango starch and seed coats on the biogas produced from mango waste. To overcome the environmental challenges, the digestate was tested and its bio-fertiliser potential proven. The study reached the conclusion that the effect of the starch on the AD biogas of mango waste is low while the effect of the seed coats is quite high. This finding supports further investigations to evaluate the effect of the production of mango starch and seed coat-based products on the profitability of AD. The highest energy balance achieved was 65% at 32 °C, 3.93 g-VS organic concentration and 37% sludge concentration, which yielded a maximum CH4 yield of 62.5%. This finding encourages the application of gate fees for accepting bio-waste, which may help in overcoming its economic challenges.

ACS Style

R. Alrefai; A.M. Alrefai; K.Y. Benyounis; J. Stokes. Enhancing the Economic Viability of Anaerobic Digestion by Exploiting the Whole Biomass of Mango Waste and Its Residues after Digestion. Energies 2020, 13, 6683 .

AMA Style

R. Alrefai, A.M. Alrefai, K.Y. Benyounis, J. Stokes. Enhancing the Economic Viability of Anaerobic Digestion by Exploiting the Whole Biomass of Mango Waste and Its Residues after Digestion. Energies. 2020; 13 (24):6683.

Chicago/Turabian Style

R. Alrefai; A.M. Alrefai; K.Y. Benyounis; J. Stokes. 2020. "Enhancing the Economic Viability of Anaerobic Digestion by Exploiting the Whole Biomass of Mango Waste and Its Residues after Digestion." Energies 13, no. 24: 6683.

Journal article
Published: 28 May 2020 in Energies
Reads 0
Downloads 0

Cassava is a form of food that is rich in starch abundant in many countries. Several bio-products can be extracted from its starch and used as an alternative for oil-based products. This study primarily aims to investigate the influence of the starch isolated from cassava peel on the quantity and quality of the biogas produced via anaerobic digestion. Beating pre-treatment was applied for the first time to isolate the starch and mechanically pre-treat the substrate. The influence of temperature, volatile solid and sludge quantity investigations were analysed with the aid of Design of Experiments (DOE). An optimisation process was applied in calculating the energy balance at the optimal results and this was needed in evaluating the impact of the starch on the biogas produced. The study revealed that the influence of the starch on the biogas quality is quite low and, as such, negligible. The largest biogas volume as obtained was 3830 cc at 37 °C, 4.2 g-VS and 50% sludge quantity, while at the same time the maximum CH4 g−1-VS was 850 cc g−1-VS at 37 °C, 1.1 g-VS and 50% sludge quantity. The optimal results show the energy gain could be achieved based on the set criteria.

ACS Style

Alla Mohammed Alrefai; Raid Alrefai; Khaled Younis Benyounis; Joseph Stokes. Impact of Starch from Cassava Peel on Biogas Produced through the Anaerobic Digestion Process. Energies 2020, 13, 2713 .

AMA Style

Alla Mohammed Alrefai, Raid Alrefai, Khaled Younis Benyounis, Joseph Stokes. Impact of Starch from Cassava Peel on Biogas Produced through the Anaerobic Digestion Process. Energies. 2020; 13 (11):2713.

Chicago/Turabian Style

Alla Mohammed Alrefai; Raid Alrefai; Khaled Younis Benyounis; Joseph Stokes. 2020. "Impact of Starch from Cassava Peel on Biogas Produced through the Anaerobic Digestion Process." Energies 13, no. 11: 2713.

Journal article
Published: 11 May 2020 in Energies
Reads 0
Downloads 0

Anaerobic digestion (AD) has undergone many developments since its first appearance. Despite that, there are still some environmental and economical obstacles that are limiting its sustainability. On the other hand, different types of starch have proven their effectiveness in some different applications. Food processing industries are considered one of the largest generators of waste in the environment. With an aid of the response surface methodology (RSM), the proposed study aimed to find an optimised way to overcome the obstacles by studying the impacts of the starch isolated from the potato peels on the biogas produced from the AD of potato peels before and after starch separation. The study found that potato peels represented approximately 12.5% of the potato total weight. The starch has only a slight influence on the quantity of the biogas produced and much lower influences on its quality. This finding suggests further investigation is required on the production of starch bio-based products simultaneously with the biogas and bio-slurry, which may mitigate environmental influences and economical obstacles of AD and make it more commercially attractive. The study showed also that the highest energy gain by the g-VS/0.2 L of potato peels was 62.9% at 35 °C, 1.62 g-VS/0.2 L organic concentration and 50% sludge concentration, which yielded a maximum CH4 of 72.4%.

ACS Style

R. Alrefai; A.M. Alrefai; K.Y. Benyounis; J. Stokes. An Evaluation of the Effects of the Potato Starch on the Biogas Produced from the Anaerobic Digestion of Potato Wastes. Energies 2020, 13, 2399 .

AMA Style

R. Alrefai, A.M. Alrefai, K.Y. Benyounis, J. Stokes. An Evaluation of the Effects of the Potato Starch on the Biogas Produced from the Anaerobic Digestion of Potato Wastes. Energies. 2020; 13 (9):2399.

Chicago/Turabian Style

R. Alrefai; A.M. Alrefai; K.Y. Benyounis; J. Stokes. 2020. "An Evaluation of the Effects of the Potato Starch on the Biogas Produced from the Anaerobic Digestion of Potato Wastes." Energies 13, no. 9: 2399.