Statistical Databases

Environmental deterioration, global climate change, and consequent increases in pollution-related health problems among populations have been attributed to growing consumption of fossil fuels in particular by the transportation sector. Hence, replacing these energy carriers, also known as major contributors of greenhouse gas emissions, with biofuels have been regarded as a solution to mitigate the above-mentioned challenges. On the other hand, efforts have been put into limiting the utilization of edible feedstocks for biofuels production, i.e., first generation biofuels, by promoting higher generations of these eco-friendly alternatives. In light of that, the present review is aimed at comprehensively assessing the role and importance of microorganisms such as bacteria and yeasts as catalysts for sustainable production of liquid biofuels including bioethanol, biomethanol, biobutanol, bio-ammonia, biokerosene, and bioglycerol. Various aspects of these biofuels, i.e., background, chemical synthesis, microbial production (including exploitation of wild and metabolically-engineered species), and product recovery as well as the derivatives produced from these biofuels which are used as fuel additives are thoroughly covered and critically discussed. Furthermore, the industrial features of these green liquid fuels including the industrial practices reported in the literature and the challenges faced as well as possible approaches to enhance these practices are presented.

A review on green liquid fuels for the transportation sector: a prospect of microbial solutions to climate change

Biomass-derived aviation fuels: Challenges and perspective

Recognizing the challenges of anaerobic digestion: Critical steps toward improving biogas generation

Analysis of biomass hydrothermal liquefaction and biocrude-oil upgrading for renewable jet fuel production: The impact of reaction conditions on production costs and GHG emissions performance

Techno-economic and environmental analysis of aviation biofuels.

For environmental reasons, the use of biokerosene as a fuel for aviation has been recently discussed more frequently especially due the fact that some air carrier accomplished regular flights with different types of such alternative fuels. Against this background, the overall goal of this paper is to provide an overview about possible conversion routes for the provision of biokerosene including an assessment of the biomass availability. Then, selected biokerosene production options are discussed in detail from a process engineering point of view. Based on these data, various conversion pathways are assessed, taking technical and economic criteria throughout the overall conversion chain into consideration. The assessment shows significant differences within the various provision routes for biokerosene. So far, only hydroprocessed esters and fatty acids (HEFA) kerosene is commercially available. Nevertheless, this possibility is not the very best choice regarding the possible feedstock and the high hydrogen consumption. Despite the biogas-to-liquid (Bio-GtL) process, all other routes need more R&D efforts to produce biokerosene in an industrial scale.

Conversion routes for production of biokerosene—status and assessment

The conversion routes for kerosene produced from biogenic alcohols are referred typically to as “Alcohol-to-Jet”-processes (AtJ). The required alcohols can be obtained via different bio-chemical and/or thermo-chemical routes from organic matter. Since both sugary and starchy biomass (with established technology) as well as lignocellulosic biomass and organic waste (with future technology) may be converted into a sugar or alcohol dilution, Alcohol-to-Jet-processes (AtJ) potentially access a broad feedstock base for future aviation biofuel supply1. Thus within this contribution firstly the various methods of alcohol production are described in detail. Then further processing of the alcohol to liquid hydrocarbon fuels is explained. Besides the “classical” bioethanol production which is globally established at industrial scale also “innovative” processes (e.g. bio-chemical production of butanol, thermo-chemical synthesis of methanol) are discussed. Thereafter, the status of the technical implementation of these various processes is presented. Finally, the main findings are summarized.

Alcohol-to-Jet (AtJ)

Background -- Feedstock -- Conversion Routes -- Fuel Standards, Quality Control and Kerosene Markets -- Experiences.

Biokerosene Status and Prospects

Large amounts of the world wide used biofuels are derived from vegetable oils; this is especially true for bio-aviation fuels. Biokerosene from vegetable oils can be produced by various processes. Three of these processes, namely the HEFA (hydroprocessed esters and fatty acids) and the BIC (biofuels iso-conversion) process as well as the co-refining in crude oil refineries, will be presented and discussed below. Therefore after a short introduction addressing the vegetable oil provision chain including different types of biomass and the different pretreatment steps to fulfill the requirements of further processing the production pathways to provide biokerosene via the different processes named above will be described. In this context a brief overview of each process is given, before each conversion step is described in detail. In the end a final consideration and a brief outlook on the future role and extend of biokerosene derived from vegetable oils is given.

Martin Kaltschmitt

Papers

Techno-economic and environmental analysis of aviation biofuels.

Conversion routes for production of biokerosene—status and assessment

Alcohol-to-Jet (AtJ)

Biokerosene Status and Prospects

Biokerosene from Vegetable Oils – Technologies and Processes