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The production of biochar by slow pyrolysis systems is a promising technology to achieve negative emissions. In this paper, an energy analysis model for a biomass-based biochar production plant utilising the slow pyrolysis process is presented. The model was used to evaluate the energy analysis of a plant processing lignocellulosic biomass. The energy analysis considered the main technical parameters of this type of plant, including the moisture content of the biomass, the moisture after drying, the pyrolysis temperature and the characteristics of the biomass. The results showed the heat losses for each component of the plant and the recoverable useful heat from the production process, which represents about 16% of the chemical energy originally contained in the biomass. Although this is a secondary output, this aspect is important for analysing the sustainability of the biochar production chain. The energy analysis enabled by the model presented is indeed a valuable tool for the technical, economic and environmental assessment of biochar production plants. [ABSTRACT FROM AUTHOR]

Bioenergy and nutrition represent two key elements in maintaining health and well‐being. Bioenergy is a form of renewable energy produced from organic materials, which can be used for generating power, while nutrition, on the other hand, is related to the ability of food to provide the proper nutrients to living beings and the factors that make up a healthy diet. The 2030 Sustainable Development Agenda has brought considerable attention to the importance of food security and nutrition, particularly under SDG2, while concurrently highlighting the need to ensure affordable, reliable, sustainable, and modern energy access for all under SDG7. The accomplishment of these two Goals is crucial for almost all others, as they are closely interconnected with many cross‐cutting elements and commonly framed in the Water Energy Food Nexus. In this context, modern bioenergy has the potential to aid in the accomplishment of the SDGs, when value chains and conversion processes are designed and managed in an appropriate and sustainable manner. Nevertheless, the positive relationship between bioenergy and nutrition is an overlooked nexus, whose analysis has been too often limited to the competition for resources, such as land, water, energy, and other inputs. Considering this, the present review was developed for both the nutrition and bioenergy communities to begin to overcome the limits of the food versus fuel paradigm, by analyzing this intricate nexus and bringing to light interlinkages and potential synergies existing between bioenergy and nutrition. So far, such linkages appear indirect or implied, therefore further research in this area would be beneficial. The strongest links between bioenergy and nutrition identified include: greater cooking efficiency, reduced indoor air pollution, and improved environmental sanitation through bioenergy clean cooking solutions; energy access for transporting, storing, and cooking food, thus reducing food loss and waste and diversifying diets; improved soil fertility through Carbon Capture and Storage (CCS), phytoremediation, and integrated biomass production systems; and better rural livelihoods and increased income by introducing bioenergy production and use as a circular economy practice. The major significance of this review is the identification of examples of good practices applied along the different stages of the bioenergy value chain with potential co‐benefits for nutrition. In this way, this work aims to provide preliminary findings for researchers to better determine the ways in which bioenergy can be deployed to improve global nutrition. This article is categorized under:Sustainable Energy > BioenergySustainable Development > GoalsSustainable Development > Energy‐Water‐Food Nexus [ABSTRACT FROM AUTHOR]

Finding a proper way to manage the enormous amount of waste plastic that is globally produced, is one of the main environmental challenges of our times. Among the different types of chemical recycling, Hydrothermal Liquefaction (HTL) appears as a potential method for the treatment of plastic waste mixes, for sustainable production of biocrude or chemicals with high added value. In this work hydrothermal liquefaction reactions were carried out on a polymeric residue, obtained from an industrial plastic waste collection and recycling process. The residue has a heterogeneous composition consisting not only of polymers but also paper and metals. Two batch experiments were performed in a stainless-steel Parr autoclave at 340 °C, investigating a residence times of 5 hours and the use of an alkaline catalyst (NaOH). The oils obtained from the reactions, as well as the aqueous phases, have been analysed by different analytical techniques such as: FT-IR spectroscopy, GC-MS, GC-FID, IC. The operating conditions used in this work, allowed the degradation of cellulose and polymers with reactive sites for hydrolysis such as PET, nylon and PVAc, while polyolefins (PE, PP) were not attacked. The use of a basic catalyst favoured a greater hydrolysis rate.

The quality of biocrudes from fast pyrolysis of lignocellulosic biomass can be improved by optimizing the downstream condensation systems to separate and concentrate selected classes of compounds, thus operating different technological solutions and condensation temperatures in multiple condensation stages. Scientific literature reports that fractional condensation can be deployed as an effective and relatively affordable step in fast pyrolysis. It consists in a controlled multiple condensation approach, which aims at the separated collection of classes of compounds that can be further upgraded to bio-derived chemicals through downstream treatments. In this study, fractional condensation has been applied to a fast pyrolysis reactor of 1 kg h-1 feed, connected to two different condensation units: one composed by a series of two spray condensers and an intensive cooler; a second by an electrostatic precipitator and an intensive cooler too. Fast pyrolysis of pinewood was conducted in a bubbling fluidized bed reactor at 500 °C, while condensable vapours were collected by an interchangeable series of condensers. Using the first configuration, high boiling point compounds – such as sugars and lignin-derived oligomers – were condensed at higher temperatures in the first stage (100 – 170 °C), while water soluble lighter compounds and most of the water were condensed at lower temperatures and so largely removed from the bio-oil. In the first two condensing stages, the bio-oil water content remained below 7 wt % (resulting in 20 MJ kg-1 of energy content) maintaining about 43% of the liquid yield, compared to the 55% of the single step condensation runs. The work thus generated promising results, confirming the interest on upscaling the fractional condensation approach to full scale biorefinering.

Introducing sustainable fuels in the different transport fields in the EU is a very challenging goal, but also a clear priority in the EU decarbonization strategy. In fact, the transport sector is extremely rigid and regulated, with consolidated norms and standards and well-defined economics. Adding more oxygenated components to the fuel mix is also limited by the so-called blend-wall: thus, the share of renewable drop-in hydrocarbons has been recently growing worldwide and in the European Union. However, as a large part of these relates to lipids, the supply of sustainable feedstock has become the major critical element of the value chain. Fast-growing demand from new sectors as Aviation also emerged, that together with Heavy Duty and Maritime represent the focus of the EC strategy, complementary to the electrification of the road transport, passenger cars and light duty vehicles. Introducing innovative processes at full commercial scale requires to overcome the Mountain of Death of processes, where the bankability of not yet demonstrated technologies is the core problem. This work addresses the impact of the EU policy scenario, depicting the status of the different process and technologies, both Bio-based and Recycled Carbon, on the Mountain of Death.

The proposed study aims at assessing the reliability of a new sludge conversion technology, based on integrating thermochemical treatment, with a chemical leaching stage for producing high quality biochar and valuable liquid with high concentration of phosphorus and other critical elements. The concept is based on the fact that sludge ash usually contains about 25% of CaO, 20% of P2O5, and about 25-30% of SiO2. With the removal of these elements, ash content is drastically reduced. The study is thus composed of two phases: (1) assessment of sludge thermochemical conversion routes, and (2) chemical leaching produced biochar. In the first phase, three thermochemical routes are investigated: HTC of fresh sludge at 80% moisture, slow pyrolysis of dry sludge, slow pyrolysis of HTC solid (hydrochar). In the second phase, the solid obtained by slow pyrolysis (biochar) is upgraded through leaching treatment to extract inorganic valuable elements: P, Mg, K. The first phase of the study demonstrated that processing dry sludge in slow pyrolysis at 450°C allows to obtain a low volatile carbonaceous product with characteristics similar to a thermal coal. Second phase demonstrated that, after acid leaching process using HNO3, ash content in biochar decreased from 41.63% to 16.67%. This method also demonstrated to be a valid solution to extract more than 90% of P, K, and Mg contained in the solid, making these elements available for being recycled in agriculture and other industrial uses. At the same time, the increase of the biochar C content and calorific value makes it a valid substitute of fossil coals.

Hydrogen is being included in several decarbonization strategies as a potential contributor in some hard-to-abate applications. Among other challenges, hydrogen storage represents a critical aspect to be addressed, either for stationary storage or for transporting hydrogen over long distances. Ammonia is being proposed as a potential solution for hydrogen storage, as it allows storing hydrogen as a liquid chemical component at mild conditions. Nevertheless, the use of ammonia instead of pure hydrogen faces some challenges, including the health and environmental issues of handling ammonia and the competition with other markets, such as the fertilizer market. In addition, the technical and economic efficiency of single steps, such as ammonia production by means of the Haber–Bosch process, ammonia distribution and storage, and possibly the ammonia cracking process to hydrogen, affects the overall supply chain. The main purpose of this review paper is to shed light on the main aspects related to the use of ammonia as a hydrogen energy carrier, discussing technical, economic and environmental perspectives, with the aim of supporting the international debate on the potential role of ammonia in supporting the development of hydrogen pathways. The analysis also compares ammonia with alternative solutions for the long-distance transport of hydrogen, including liquefied hydrogen and other liquid organic carriers such as methanol. [ABSTRACT FROM AUTHOR]