Slow pyrolysis of lignin rich residue from lignocellulosic biorefining operations

Europe is committed to have a bio-based economy in 2030. It follows that a huge contribution of biorefinery products on the European demand for chemicals, energy, materials and fibers is expected in the near future. To be environmentally and economically sustainable, biorefinery will need to be flexible, versatile, energy and cost efficient [1]. In a lignocellulose based biorefinery, the sugar platform that leads to bioethanol and added-value products through biochemical processes represents a challenging option. After ethanol distillation a lignin reach residue (LRR) is produced and used as energy source. However, it is currently underutilized with about 60% more lignin generated than is needed to meet the internal energy use [2, 3]. The exploitation of this residue for the combined production of biofuels and added value chemicals and materials represents a key factor for the increase of the efficiency of the overall ethanol production chain and its valorization is mandatory for the viability of future biorefinery operations. Please click Additional Files below to see the full abstract

Pyrolysis atmosphere effect on biochar properties and PTEs behaviour

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A Community-Structure-Based Method for Estimating the Fractal Dimension, and its Application to Water Networks for the Assessment of Vulnerability to Disasters

Most real-world networks, from the World-Wide-Web to biological systems, are known to have common structural properties. A remarkable point is fractality, which suggests the self-similarity across scales of the network structure of these complex systems. Managing the computational complexity for detecting the self-similarity of big-sized systems represents a crucial problem. In this paper, a novel algorithm for revealing the fractality, that exploits the community structure principle, is proposed and then applied to several water distribution systems (WDSs) of different size, unveiling a self-similar feature of their layouts. A scaling-law relationship, linking the number of clusters necessary for covering the network and their average size is defined, the exponent of which represents the fractal dimension. The self-similarity is then investigated as a proxy of recurrent and specific response to multiple random pipe failures – like during natural disasters – pointing out a specific global vulnerability for each WDS. A novel vulnerability index, called Cut-Vulnerability is introduced as the ratio between the fractal dimension and the average node degree, and its relationships with the number of randomly removed pipes necessary to disconnect the network and with some topological metrics are investigated. The analysis shows the effectiveness of the novel index in describing the global vulnerability of WDSs

The faster the better: On the shortest paths role for near real-time decision making of water utilities

Near real-time monitoring and control of critical infrastructure is essential for the operation and management of cities in a world that is, today, more complex and interconnected than ever. Such an infrastructure can be represented as complex networks an some of their related indices and statistics, many of them based on the shortest paths, play a pivotal role in the decision making for public services such as internet, energy or water. Particularly, the literature has shown that shortest paths are key for resilience and criticality assessment in a water distribution systems (WDS). This paper proposes a procedure to speed-up the computation of shortest paths in a WDS, as it can straightforwardly benefit any critical infrastructure. The proposal is based on a reduced dimension of a complex network representing any critical infrastructure. Despite the consequent decrease in the number of all possible paths in the network, the main advantage and novelty of this proposal is to continue finding the exact solution for the shortest paths. Experimental results show that the procedure brings a computational-time reduction consistently over 50% and up to 90% in some cases. In addition, the paper reveals how the use of shortest paths benefits WDS operation and management, as well as playing a key role in near real-time contamination detection and leakage control

Fate of lead and other heavy metals during pyrolysis of lignocellulosic biomass

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A Community-Structure-Based Method for Estimating the Fractal Dimension, and its Application to Water Networks for the Assessment of Vulnerability to Disasters

AbstractMost real-world networks, from the World-Wide-Web to biological systems, are known to have common structural properties. A remarkable point is fractality, which suggests the self-similarity across scales of the network structure of these complex systems. Managing the computational complexity for detecting the self-similarity of big-sized systems represents a crucial problem. In this paper, a novel algorithm for revealing the fractality, that exploits the community structure principle, is proposed and then applied to several water distribution systems (WDSs) of different size, unveiling a self-similar feature of their layouts. A scaling-law relationship, linking the number of clusters necessary for covering the network and their average size is defined, the exponent of which represents the fractal dimension. The self-similarity is then investigated as a proxy of recurrent and specific response to multiple random pipe failures – like during natural disasters – pointing out a specific global vulnerability for each WDS. A novel vulnerability index, called Cut-Vulnerability is introduced as the ratio between the fractal dimension and the average node degree, and its relationships with the number of randomly removed pipes necessary to disconnect the network and with some topological metrics are investigated. The analysis shows the effectiveness of the novel index in describing the global vulnerability of WDSs

Overview of Energy Management and Leakage Control Systems for Smart Water Grids and Digital Water

Current and future smart cities are moving towards the zero-net energy use concept. To this end, the built environment should also be designed for efficient energy use and play a significant role in the production of such energy. At present, this is achieved by focusing on energy demand in buildings and to the renewable trade-off related to smart power grids. However, urban water distribution systems constantly carry an excess of hydraulic energy that can potentially be recovered to produce electricity. This paper presents a comprehensive review of current strategies for energy production by reviewing the state-of-the-art of smart water systems. New technologies (such as cyber-physical systems, digital twins, blockchain) and new methodologies (network dynamics, geometric deep learning) associated with digital water are also discussed. The paper then focuses on modelling the installation of both micro-turbines and pumps as turbines, instead of/together with pressure reduction valves, to further demonstrate the energy-recovery methods which will enable water network partitioning into district metered areas. The associated benefits on leakage control, as a source of energy, and for contributing to overall network resilience are also highlighted. The paper concludes by presenting future research directions. Notably, digital water is proposed as the main research and operational direction for current and future Water Distribution Systems (WDS) and as a holistic, data-centred framework for the operation and management of water networks.</jats:p

Perspectives in the use of biochars as low-cost CO2 adsorbents

The recognized versatility of biochar in environmental remediation issues opened up an increasing interest in its applications in multidisciplinary areas of science and engineering. Possible biochar applications include carbon sequestration, soil fertility improvement, pollution remediation and agricultural by-product/waste recycling. A proper application in specific environmental areas requires a fulfilled biochar chemico-physical characterization and overall properties. Please click on the file below for full content of the abstract

Effect of pyrolysis conditions on sewage sludge derived biochars for high value composites applications

The economy of the whole wastewater treatment system is significantly burdened by the increasing amounts of sewage sludge due to the progressive implementation of the Urban Waste Water Treatment Directive 91/271/EEC and by the complexity of the treatments required for guaranteeing a safe handling and a proper end-of-life of the sludge. For this reason, thermal treatments of sewage sludge have been studied in the past for their efficient valorization in terms of energy and/or matter recovery. Among them, pyrolysis represents a viable route aiming at the recycling of resources without production of harmful substances to the humans or the environment. A lot of work has been done on the use of sludge-derived char as a fertilizer and soil conditioner showing its safer application with respect to the untreated sludge. The nutrients were intensified with the temperature rising (except nitrogen) and the bioavailability and the leaching of heavy metals was reduced [1]. However, the physical and chemical characteristics of biochar can be exploited also for the production of high value-added materials. Carbon materials such as nanotubes received a great attention due to their ability to enhance mechanical, electrical and thermal properties of polymer composites [2], but high costs and low reproducibility have discouraged their use. In this study sludge-derived char (SCHAR) is studied as a possible alternative to other high cost carbon fillers. Sewage sludge from a civil wastewater treatment plant was pyrolyzed both in slow [3] and fast [4] pyrolysis conditions at three different temperatures, 500, 600 and 700 °C. A lignocellulosic biomass was also processed in the same experimental conditions for comparing the SCHARs with typical biochars (BCHARs). Please click Additional Files below to see the full abstract