Microalgae has been identified as a potential feedstock for biodiesel production since its cultivation requires less cropland compared to conventional oil crops and the high growth rate of microalgae. Research on microalgae oils often are focused on microalgae oil extraction and biomass harvesting techniques. However, energy intensive and costly lipid extraction methods are the major obstacles hampering microalgae biodiesel commercialisation. Direct biodiesel synthesis avoids such problems as it combines lipid extraction techniques and transesterification into a single step. In this review, the potential of direct biodiesel synthesis from microalgae biomass was comprehensively analysed. The various species of microalgae commonly used as biodiesel feedstock was critically assessed, particularly on high lipid content species. The production of microalgae biodiesel via direct conversion from biomass was systematically discussed, covering major enhancements such as heterogeneous catalysts, the use of ultrasonic and microwave- techniques and supercritical alcohols that focus on the overall improvement of biodiesel production. In addition, this review illustrates the cultivation conditions for biomass growth and lipid productivity improvement, the available harvesting and lipid extraction technologies, as well as the key challenges and future prospect of microalgae biodiesel production. This review serves as a basis for future research on direct biodiesel synthesis from modified microalgae biomass to improve profitability of microalgae biodiesel.

Sustainability of direct biodiesel synthesis from microalgae biomass: a critical review.

https://www.econstor.eu/bitstream/10419/243693/1/1683639065.pdf

A review of global current scenario of biodiesel adoption and combustion in vehicular diesel engines

Research on the performance of a hydrogen/methanol dual-injection assisted spark-ignition engine using late-injection strategy for methanol

Alternative fuels are essential to enable the transition to a sustainable and environmentally friendly energy supply. Synthetic fuels derived from renewable energies can act as energy storage media, thus mitigating the effects of fossil fuels on environment and health. Their economic viability, environmental impact, and compatibility with current infrastructure and technologies are fuel and power source specific. Nitrogen-based fuels pose one possible synthetic fuel pathway. In this review, we discuss the progress and current research on utilization of nitrogen-based fuels in power applications, covering the complete fuel cycle. We cover the production, distribution, and storage of nitrogen-based fuels. We assess much of the existing literature on the reactions involved in the ammonia to nitrogen atom pathway in nitrogen-based fuel combustion. Furthermore, we discuss nitrogen-based fuel applications ranging from combustion engines to gas turbines, as well as their exploitation by suggested end-uses. Thereby, we evaluate the potential opportunities and challenges of expanding the role of nitrogen-based molecules in the energy sector, outlining their use as energy carriers in relevant fields.

Progress and Prospective of Nitrogen-Based Alternative Fuels.

Microalgae have been widely explored because of the diverse number of their worthwhile applications and potential as a source biomass for the production of biofuels and value-added materials. However, downstream techniques have yet to be fully developed to overcome techno-economic barriers. Flocculation is a superior method for harvesting microalgae from growth medium because of its harvesting efficiency, economic feasibility. Various kind of bio-flocculation harvesting methods are consider as attractive low cost and environmentally friendly options and able to harvest >90% biomass. Lipid recovery from microalgal cells is a major barrier for the biofuel industry because of process complexity and algae cell structure. Thus, the pretreatment method is necessary to disrupt the cell walls of microalgae and enhance lipid extraction. Many techniques, including dry methods of extraction, are already being implemented but found out that they are not efficient and cost-effective. Various new wet harvesting strategies have been claimed to extract major lipids in cost-efficient (30% less than conventional) way as wet technologies can eliminate the cost of cell drying and associated instruments. It is necessary to develop new methods which are energy and cost-effective, and environmentally friendlier for the commercialization of biofuels. Therefore, this review presents the advances in the progress of various flocculation harvesting methods with special emphasis on innovative bio-flocculation, the underlying mechanism of microalgae and flocculation. In this study also summarize the recent progress on microalgal oil extraction processes, and comparison was made between the processes in terms of sustainability, technology readiness, and applications in larger scales.

Modern developmental aspects in the field of economical harvesting and biodiesel production from microalgae biomass

Numerical investigation on effects of nozzle’s geometric parameters on the flow and the cavitation characteristics within injector’s nozzle for a high-pressure common-rail DI diesel engine

Propagation characteristics of laminar spherical flames within homogeneous hydrogen-air mixtures

Turbulence influence on explosion characteristics of stoichiometric and rich hydrogen/air mixtures in a spherical closed vessel

The prices of primary energy have been ineluctably raised up due to the enormous energy consumption in China, and the economy suffers a lot from the severe energy shortage. Therefore, the necessity of using renewable energy in China is particularly important. Biodiesel has become one of the major renewable fuels of biomass energy. Since China׳s biodiesel industry just starts at the primary stage, improving the production capacity of biodiesel for meeting the soaring on energy demands is more necessary for the sustainable development in China. The materials for biodiesel production are various and sufficient in China, that indicates China could have a brilliant potentiality in the production capacity of biodiesel; however, whether such prediction could be true is still needed to be discussion in depth and further. For well answering the query, the development of biodiesel industry in China has been systematically reviewed upon the terms of production and consumption, and three essential aspects (‘how to sufficiently take advantage of such plentiful feedstock for obtaining a satisfied production capacity’, ‘how to reasonably use such biodiesel in each region’, and ‘how to scientifically encourage the development of Chinese biodiesel industry’) have been discussed. From the review and discussions, it can be concluded that the rising China׳s biodiesel industry is still behind the actual demand asked by 12th Five-Years Plan and continuous introduction of capitals is the effective method to a further development. Meanwhile, the development of China׳s biodiesel industry is highly depended on the raw materials whose sources and production capability are remarkably different in different regions, and hence make standards on the quality of biodiesel is essential and crucial to the further development. Furthermore, adjusting tax policies and forcing the application of biodiesel as addition to fossil diesel can effective establish and enlarge the market of biodiesel in China.

Development of biodiesel industry in China: upon the terms of production and consumption.

Experimental investigation on laminar burning velocities and flame intrinsic instabilities of lean and stoichiometric H2/CO/air mixtures at reduced, normal and elevated pressures

Guo-Xiu Li

Papers

Numerical investigation on effects of nozzle’s geometric parameters on the flow and the cavitation characteristics within injector’s nozzle for a high-pressure common-rail DI diesel engine

Propagation characteristics of laminar spherical flames within homogeneous hydrogen-air mixtures

Turbulence influence on explosion characteristics of stoichiometric and rich hydrogen/air mixtures in a spherical closed vessel

Development of biodiesel industry in China: upon the terms of production and consumption.

Experimental investigation on laminar burning velocities and flame intrinsic instabilities of lean and stoichiometric H2/CO/air mixtures at reduced, normal and elevated pressures