Glycerol production and its applications as a raw material: A review
TL;DR: This paper reviews different methods of producing crude glycerol as the major by-product of biodiesel production by transesterification, soap manufacturing by saponification as well as hydrolysis reaction.
Abstract: Glycerol is a valuable byproduct in biodiesel production by transesterification, soap manufacturing by saponification as well as hydrolysis reaction. The purity of glycerol obtained is low due to the presence of impurities such as remaining catalyst, water, soaps, salts and esters formed during the reaction. Purification of glycerol as well as the conversion of glycerol into valuable products has attained growing interest in recent years due to the dramatic growth of the biodiesel industry. This paper reviews different methods of producing crude glycerol as the major by-product. Purification of glycerol was reported as well as value-added products produced from glycerol.
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TL;DR: A review and analysis of patents related to the use of glycerol in the period from 1993 to 2015, showing the quantity and diversity of work related to search for alternatives to add value to glycerols as discussed by the authors.
Abstract: Increases in biodiesel production have led to a surplus of crude glycerol, which represents a major bottleneck in the biodiesel production chain and has created new challenges to its sustainable use. Although there is a wide range of potential uses for crude glycerol, they are limited by its degree of purity, which affects its physical, chemical and biological properties. This paper presents a review and analysis of patents related to the use of glycerol in the period from 1993 to 2015, showing the quantity and diversity of work related to the search for alternatives to add value to glycerol. It was found that 85.7% of the filed patents fell into four categories of applications: 1) manufacture of chemical products; 2) production of polymer compounds; 3) production of biofuels and biogas; and 4) purification and use of glycerol. In this regard, the development of new technologies for the use of glycerol, without the need for traditional purification steps, are fundamental. This paper portrays the efforts that have been made in this direction and the obstacles that still have to be overcome.
331 citations
TL;DR: The fundamental aspects of the production of PUFs are reviewed, the new challenges that the PUFs industry are expected to confront regarding process methodologies in the near future are outlined, and some alternatives are also presented.
Abstract: Polymeric foams can be found virtually everywhere due to their advantageous properties compared with counterparts materials. Possibly the most important class of polymeric foams are polyurethane foams (PUFs), as their low density and thermal conductivity combined with their interesting mechanical properties make them excellent thermal and sound insulators, as well as structural and comfort materials. Despite the broad range of applications, the production of PUFs is still highly petroleum-dependent, so this industry must adapt to ever more strict regulations and rigorous consumers. In that sense, the well-established raw materials and process technologies can face a turning point in the near future, due to the need of using renewable raw materials and new process technologies, such as three-dimensional (3D) printing. In this work, the fundamental aspects of the production of PUFs are reviewed, the new challenges that the PUFs industry are expected to confront regarding process methodologies in the near future are outlined, and some alternatives are also presented. Then, the strategies for the improvement of PUFs sustainability, including recycling, and the enhancement of their properties are discussed.
330 citations
Cites background from "Glycerol production and its applica..."
...Glycerol can be obtained as a sub product of many reactions, such the saponification or the hydrolysis of triglycerides [120]....
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TL;DR: This review focuses on current technologies for the production of polyhydroxyalkanoates (PHA) from food waste, with particular attention paid to fermentation technologies based on pure and mixed cultures.
297 citations
Cites background from "Glycerol production and its applica..."
...In total, 172 million kg of glycerol are generated annually through biodiesel production across the globe (Tan et al., 2013)....
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TL;DR: The lignocellulosic SCO-based biorefinery will be feasible only if a combination of low- and high-value lipids are coproduced, while lignin and protein are upgraded to high- value products.
253 citations
TL;DR: In this paper, a review of recent advances in the synthesis of polyethylene terephthalate (PET) monomers from biomass is presented, where the advantages and drawbacks of each route are discussed in terms of feedstock, reaction pathway, catalyst and economic evaluation.
230 citations
References
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TL;DR: As demonstrated here, microalgae appear to be the only source of renewable biodiesel that is capable of meeting the global demand for transport fuels.
9,030 citations
"Glycerol production and its applica..." refers background in this paper
...[34] Rodolfi L, Zittelli GC, Bassi N, Padovani G, Biondi N, Bonini G. Microalgae for oil: strain selection, induction of lipid synthesis and outdoor mass cultivation in a low cost photobioreactor....
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...Third generation Microalgae [15,18,28,29] – Fast reproduction as they are easier to cultivate [28]...
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TL;DR: In this article, the authors reviewed the technologies underpinning microalgae-to-bio-fuels systems, focusing on the biomass production, harvesting, conversion technologies, and the extraction of useful co-products.
Abstract: Sustainability is a key principle in natural resource management, and it involves operational efficiency, minimisation of environmental impact and socio-economic considerations; all of which are interdependent. It has become increasingly obvious that continued reliance on fossil fuel energy resources is unsustainable, owing to both depleting world reserves and the green house gas emissions associated with their use. Therefore, there are vigorous research initiatives aimed at developing alternative renewable and potentially carbon neutral solid, liquid and gaseous biofuels as alternative energy resources. However, alternate energy resources akin to first generation biofuels derived from terrestrial crops such as sugarcane, sugar beet, maize and rapeseed place an enormous strain on world food markets, contribute to water shortages and precipitate the destruction of the world's forests. Second generation biofuels derived from lignocellulosic agriculture and forest residues and from non-food crop feedstocks address some of the above problems; however there is concern over competing land use or required land use changes. Therefore, based on current knowledge and technology projections, third generation biofuels specifically derived from microalgae are considered to be a technically viable alternative energy resource that is devoid of the major drawbacks associated with first and second generation biofuels. Microalgae are photosynthetic microorganisms with simple growing requirements (light, sugars, CO 2 , N, P, and K) that can produce lipids, proteins and carbohydrates in large amounts over short periods of time. These products can be processed into both biofuels and valuable co-products. This study reviewed the technologies underpinning microalgae-to-biofuels systems, focusing on the biomass production, harvesting, conversion technologies, and the extraction of useful co-products. It also reviewed the synergistic coupling of microalgae propagation with carbon sequestration and wastewater treatment potential for mitigation of environmental impacts associated with energy conversion and utilisation. It was found that, whereas there are outstanding issues related to photosynthetic efficiencies and biomass output, microalgae-derived biofuels could progressively substitute a significant proportion of the fossil fuels required to meet the growing energy demand.
4,432 citations
TL;DR: The experiments showed that the eustigmatophyte Nannochloropsis sp.
Abstract: Thirty microalgal strains were screened in the laboratory for their biomass productivity and lipid content. Four strains (two marine and two freshwater), selected because robust, highly productive and with a relatively high lipid content, were cultivated under nitrogen deprivation in 0.6-L bubbled tubes. Only the two marine microalgae accumulated lipid under such conditions. One of them, the eustigmatophyte Nannochloropsis sp. FM102: 100–112. © 2008 Wiley Periodicals, Inc.
2,714 citations
TL;DR: The results suggested that the new process, which combined bioengineering and transesterification, was a feasible and effective method for the production of high quality biodiesel from microalgal oil.
1,379 citations
"Glycerol production and its applica..." refers methods in this paper
...Miao and Wu [17] produced biodiesel from microalgae lipids using sulphuric acid as a catalyst via transesterification process....
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TL;DR: In this article, the transesterification of vegetable oils with methanol as well as the main uses of the fatty acid methyl esters are reviewed. But, the anchored catalysts show leaching problems.
Abstract: The transesterification of vegetable oils with methanol as well as the main uses of the fatty acid methyl esters are reviewed. The general aspects of this process and the applicability of different types of catalysts (acids, alkaline metal hydroxides, alkoxides and carbonates, enzymes and non-ionic bases, such as amines, amidines, guanidines and triamino(imino)phosphoranes) are described. Special attention is given to guanidines, which can be easily heterogenized on organic polymers. However, the anchored catalysts show leaching problems. New strategies to obtain non-leaching guanidine-containing catalysts are proposed. Finally, several applications of fatty acid esters, obtained by transesterification of vegetable oils, are described.
1,293 citations
"Glycerol production and its applica..." refers background in this paper
...[49] and Demirbas [50] reported the mechanism of base catalysed transesterification process of vegetable oils....
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