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Hydrogen Storage in Geological Formations—The Potential of Salt Caverns
Aleksandra Małachowska, Natalia Łukasik, Joanna Mioduska, Jacek Gębicki
February 27, 2023 (v1)
Subject: Materials
Keywords: geological formations, Hydrogen, salt caverns, underground energy storage
Hydrogen-based technologies are among the most promising solutions to fulfill the zero-emission scenario and ensure the energy independence of many countries. Hydrogen is considered a green energy carrier, which can be utilized in the energy, transport, and chemical sectors. However, efficient and safe large-scale hydrogen storage is still challenging. The most frequently used hydrogen storage solutions in industry, i.e., compression and liquefaction, are highly energy-consuming. Underground hydrogen storage is considered the most economical and safe option for large-scale utilization at various time scales. Among underground geological formations, salt caverns are the most promising for hydrogen storage, due to their suitable physicochemical and mechanical properties that ensure safe and efficient storage even at high pressures. In this paper, recent advances in underground storage with a particular emphasis on salt cavern utilization in Europe are presented. The initial experience in... [more]
Traction Load Modeling and Parameter Identification Based on Improved Sparrow Search Algorithm
Zhensheng Wu, Deling Fan, Fan Zou
February 27, 2023 (v1)
Keywords: improved sparrow search algorithm, load modeling, parameter identification, traction load
In this paper, a traction load model parameter identification method based on the improved sparrow search algorithm (ISSA) is proposed. According to the load characteristics of the AC traction power supply system under transient disturbance, the model structure of the traction load is equated to the composite load model structure of the static load shunt induction motor’s dynamic load. The traditional sparrow search algorithm is improved to enhance its accuracy and convergence. The generalization ability of the model was tested, and the accuracy of the proposed model was verified. Using the ISSA to determine the load model from the measured data, the results can verify the effectiveness of the ISSA for comprehensive load model parameter identification. Comparing the ISSA with the traditional SSA and PSO algorithms, it shows that the ISSA has better accuracy and convergence.
Improved Whale Optimization Algorithm for Transient Response, Robustness, and Stability Enhancement of an Automatic Voltage Regulator System
Salman Habib, Ghulam Abbas, Touqeer A. Jumani, Aqeel Ahmed Bhutto, Sohrab Mirsaeidi, Emad M. Ahmed
February 27, 2023 (v1)
Subject: Optimization
Keywords: automatic voltage regulator, dynamic response enhancement, improved whale optimization algorithm, stability, whale optimization algorithm
The proportional integral derivative (PID) controller is one of the most robust and simplest configuration controllers used for industrial applications. However, its performance purely depends on the tuning of its proportional (KP), integral (KI) and derivative (KD) gains. Therefore, a proper combination of these gains is primarily required to achieve an optimal performance of the PID controllers. The conventional methods of PID tuning such as Cohen-Coon (CC) and Ziegler−Nichols (ZN) generate unwanted overshoots and long-lasting oscillations in the system. Owing to the mentioned problems, this paper attempts to achieve an optimized combination of PID controller gains by exploiting the intelligence of the whale optimization algorithm (WOA) and one of its recently introduced modified versions called improved whale optimization algorithm (IWOA) in an automatic voltage regulator (AVR) system. The stability of the IWOA-AVR system was studied by assessing its root-locus, bode maps, and pole/... [more]
Carbon Emission Trading and Corporate Financing: Evidence from China
Li Meng, Ke Wang, Taoyong Su, He He
February 27, 2023 (v1)
Keywords: carbon emission trading, corporate financing, manufacturing firm
As an important tool to control CO2 emission, carbon emission trading (CET) has been highlighted in prior studies for its positive effects on firms. However, we are concerned about the role of the CET in corporate financing. Through a quasi-natural experiment from China’s CET pilot, regarded as the start-up stage of China’s emission trading system, we investigate the manufacturing corporate financing (i.e., debt and commercial credit financing). The results show that the firms in China’s CET market have less debt financing. Additionally, in the heterogeneity analysis, we found that (1) the CET is negatively related to corporate financing when their financing constraints are weak, whereas it only reduces long-term debt for the firms with strong financing constraints. (2) The impact of the CET on corporate financing is not significant for the firms located in first-tier cities in China, but in other cities, the CET negatively influences firms’ long-term debt and contributes to commercial... [more]
Large Air-to-Water Heat Pumps for Fuel-Boiler Substitution in Non-Retrofitted Multi-Family Buildings—Energy Performance, CO2 Savings, and Lessons Learned in Actual Conditions of Use
Omar Montero, Pauline Brischoux, Simon Callegari, Carolina Fraga, Matthias Rüetschi, Edouard Vionnet, Nicole Calame, Fabrice Rognon, Martin Patel, Pierre Hollmuller
February 27, 2023 (v1)
Keywords: actual performance, air to water heat pump, in-situ monitoring, monovalent and hybrid system, multi-family building, retrofit
The use of air source heat pumps (ASHP) in the specific context of existing multi-family buildings (MFB) represents an important challenge, especially in terms of performance and technical constraints in real conditions of use. This study concerns the actual performance of two non-retrofitted MFB (4047 and 7563 m2), whose original fossil heat supply was replaced by a centralized monovalent (2 × 156 kW) and hybrid (6 × 34 kW) ASHP system for space heating and domestic hot water. Based on a detailed monitoring campaign covering two years of operation, it can be concluded that both systems are able to supply the required temperature and cover the entire heat demand. By closely following up these pilot projects, constraints linked to integration and operation were identified. Optimization measures allowed us to increase the COP of the monovalent system (from 1.3 up to 3.4, with an optimized SPF of 2.3) and to raise the HP share of the hybrid system (from 50% to 67%, with an optimized SPF o... [more]
Modelling and Calculation of Raw Material Industry
Krzysztof Czajka, Witold Kawalec, Robert Król, Izabela Sówka
February 27, 2023 (v1)
Subject: Materials
Keywords: air pollution, emission reduction methods, energy conversion and storage, energy recovery, heating and energy processes, purification and removal techniques, raw material sustainable-use fossil fuels, sustainable mining
Scientific and technical issues related to the extraction and processing of raw materials are inextricably linked with environmental concerns. The extraction, transportation and processing of raw materials and the creation of new products place a heavy burden on the environment. Therefore, the development of new technologies for the extraction and processing of raw materials which meet the demand for specific products while respecting environmental resources and saving energy can be considered one of the key challenges of modern science. The development of methods to optimize the course of certain processes related to the raw materials industry, limiting its impact on the environment, and the use of modern measurement techniques or modeling are key areas of research and development for the economy. The aim of this Special Issue was to identify certain important issues, including those related to the raw materials industry and the optimization of its processes, obtaining energy from alt... [more]
Mechanism of Casing String Curvature Due to Displacement of Surface Strata
Maciej Dutkiewicz, Ivan Shatskyi, Oleh Martsynkiv, Eduard Kuzmenko
February 27, 2023 (v1)
Subject: Environment
Keywords: conductor casing, curvature, moving surface strata, stresses calculation
One of the main problems of well operation is the risk of uncontrolled leakage of hydrocarbons into the environment. This problem is especially relevant for the long-term operation of wells. The idea for this study was inspired by a real industrial problem that the authors of the article were involved in solving. At several operating gas wells, an abnormal slope of the production tree occurred, which raised the question of the safety of their further operation. An analysis of known studies and current regulatory documents did not allow us to assess the safety of using a gas well based on the measured kinematic parameters of production tree deviations. A mathematical model for the deformation of a package of casing strings when the surface layer of the rock is displaced is developed in the article. A boundary value problem is formulated for differential equations of pipe bending on an elastic foundation. Based on the results of solving this problem, an unambiguous relationship was estab... [more]
Comparison of Different Topologies of Thermal Management Subsystems in Multi-Stack Fuel Cell Systems
Wei Shen, Lei Fan, Zhirong Pan, Chunguang Chen, Ning Wang, Su Zhou
February 27, 2023 (v1)
Keywords: MFCS, operating temperature, thermal management subsystem, topology
The performance of a fuel cell stack is affected by the operating temperature of the stack. The thermal management subsystem of a multi-stack fuel cell system (MFCS) is particularly significant for the operating temperature control of each stack in the MFCS. To study the influence of different topologies of a MFCS thermal management subsystem, this paper proposes and establishes two different topologies. Firstly, the integrated topology is proposed. Secondly, seven component models, namely the mixer, thermostat, radiator, tank, pump, bypass value, and proton exchange membrane fuel cell stack temperature models, are described in detail. Finally, the performance of the two topologies of the MFCS thermal management subsystem under two working conditions, steady (200 A) and variable (China heavy-duty commercial test cycle, C-WTVC), is compared. Furthermore, there are two evaluating indicators, including the stability duration and deviation of the operating temperatures of the single stack... [more]
Combining Deep Learning and the Heat Flux Method for In-Situ Thermal-Transmittance Measurement Improvement
Sanjin Gumbarević, Bojan Milovanović, Bojana Dalbelo Bašić, Mergim Gaši
February 27, 2023 (v1)
Keywords: building physics, deep learning, Energy Efficiency, Machine Learning, thermal transmittance
Transmission losses through the building envelope account for a large proportion of building energy balance. One of the most important parameters for determining transmission losses is thermal transmittance. Although thermal transmittance does not take into account dynamic parameters, it is traditionally the most commonly used estimation of transmission losses due to its simplicity and efficiency. It is challenging to estimate the thermal transmittance of an existing building element because thermal properties are commonly unknown or not all the layers that make up the element can be found due to technical-drawing information loss. In such cases, experimental methods are essential, the most common of which is the heat-flux method (HFM). One of the main drawbacks of the HFM is the long measurement duration. This research presents the application of deep learning on HFM results by applying long-short term memory units on temperature difference and measured heat flux. This deep-learning r... [more]
Isobaric Expansion Engine Compressors: Thermodynamic Analysis of the Simplest Direct Vapor-Driven Compressors
Alexander Kronberg, Maxim Glushenkov, Sander Roosjen, Sascha Kersten
February 27, 2023 (v1)
Keywords: Energy Efficiency, heat-driven compressor, isobaric expansion engine, low-grade heat, piston compressor
Isobaric expansion (IE) technology is a promising solution for mini- and medium-scale low-grade heat utilization. IE engines directly convert heat to mechanical energy and are particularly interesting as direct-acting, vapor-driven pumps and compressors. The elimination of multiple energy transformations, technical simplicity and the ability to use widely available low-grade heat (<100 °C) instead of fossil fuels are attractive features of this technology. The purpose of this paper was to present a new compression technology based on IE Worthington type engines, analyze the process analytically and numerically, and provide a first assessment of its potential. The simplest single- and double-acting schemes were considered for arbitrary low and high pressures of the compressed gas/vapor and driving vapor. In these schemes, the compressor piston was rigidly connected to that of an engine/driver. The vapor use efficiency of the driver process was characterized by the ratio of the networ... [more]
Optimal Planning of Electric Vehicle Charging Stations Considering User Satisfaction and Charging Convenience
Di Xu, Wenhui Pei, Qi Zhang
February 27, 2023 (v1)
Keywords: charging station, electric vehicles, immune algorithm, Optimization
To solve the problem of layout design of charging stations in the early stage of the electric vehicle industry, the user’s satisfaction and the charging convenience are considered. An electric vehicle charging station site-selection model is established based on the kernel density analysis of the urban population. The goal of this model is maximum electric vehicle user satisfaction and the highest charging convenience. Then, according to model characteristics, the immune algorithm is designed and optimized to solve the model. The optimization of the immune algorithm includes two aspects. On the one aspect, judging that the stop condition is added in the mutation link. On the other aspect, two mutation operators are designed in the optimized immune algorithm. Finally, the simulation example is determined by a three-step method in Jinan City. The results show that the electric vehicle charging station site-selection model in this paper can better meet user needs compared with traditional... [more]
Sintering and Fusibility Risks of Pellet Ash from Different Sources at Different Combustion Temperatures
Juan Carlos Contreras-Trejo, Daniel José Vega-Nieva, Maginot Ngangyo Heya, José Angel Prieto-Ruíz, Cynthya Adriana Nava-Berúmen, Artemio Carrillo-Parra
February 27, 2023 (v1)
Keywords: ash, Biomass, pellets, sintering, slag
Pellets are solid biofuels with a combustion efficiency of 85−90%, low CO2 emissions and costs, great comfort and versatility. However, the ash generated during combustion can present sintering and fusibility, decreasing boiler efficiency and potentially malfunctioning. Ash composition indexes can be useful to predict observed ash sintering and fusion but require further analysis for a variety of feedstocks. The objective of this work was to determine the effect of the mineral composition of pellet ash from 15 biomasses of forest and agro-industrial sources on observed pellet ash slagging using a laboratory test. The chemical composition of pellets and the indexes B, NaK/B, SiP/CaMg and SiPNaK/CaMg at 550 and 1000 °C were determined. Pearson correlation tests were also performed between cumulative percentages of slag at different sieve sizes. The concentrations of CaO ranged from 4.49 to 65.95%, MgO varied from 1.99 to 17.61%, and the SiO2 concentration was between 16.11 and 28.24% and... [more]
Dual Isolated Multilevel Modular Inverter with Novel Switching and Voltage Stress Suppression
Saud Alotaibi, Xiandong Ma, Ahmed Darwish
February 27, 2023 (v1)
Keywords: modular inverters, photovoltaic systems, power electronic converters, reduced number of switches
This paper presents an improved structure for the submodules (SMs) in the three-phase modular inverter (TPMI) based on a dual isolated SEPIC/CUK (DISC) converter for large-scale photovoltaic (LSPV) plants. The DISC SMs can offer several advantages, including increased efficiency, reduced passive elements, and galvanic isolation via compact-size high-frequency transformers. The SMs can also provide a wide range for the output voltage and draw continuous currents with low ripples from the input source. However, the high dv/dt value across the switches during hard switching can cause current oscillations and voltage spikes, which will impair the operation of complementary switches and affect the safety of the power devices. For this challenge, the DISC SM is improved by replacing the output switches with diodes and adding a bypassing switch. In comparison to the conventional DISC SM, the improved DISC SM reduces the switch’s voltage spikes; hence, it can increase the overall efficiency. T... [more]
Analysis of AVAZ Seismic Forward Modeling of Fracture-Cavity Reservoirs of the Dengying Formation, Central Sichuan Basin
Yisheng Liu, Zhengping Zhu, Renfang Pan, Bole Gao, Jineng Jin
February 27, 2023 (v1)
Keywords: anisotropy, AVAZ, forward modeling, fracture-cavity reservoir, HTI medium
For the purpose of clarifying the seismic response characteristics of fractured-cavity reservoirs of Dengying Formation in the central Sichuan Basin, the paper first intends to establish three geological models of fracture cave reservoirs based on drilling, logging, and core data of the Dengying Formation in the central Sichuan Basin. Then, the formation reflection is calculated with reference to anisotropic Horizontal Transverse Isotropy (HTI) medium. Finally, further research on Amplitude Variation with Azimuth (AVAZ) seismic forward modeling has been conducted to clarify the seismic response characteristics of different reservoir types in the study area. The results suggest that: Seismic response characteristics of fractured-cavity reservoirs are controlled by incident angle and azimuth angle of seismic waves in different types of reservoirs. The incident angle of the seismic wave controls the difference in amplitude caused by different micro-fracture densities, and the azimuth angl... [more]
Calculation Model for Progressive Residual Surface Subsidence above Mined-Out Areas Based on Logistic Time Function
Chunyi Li, Laizhong Ding, Ximin Cui, Yuling Zhao, Yihang He, Wenzhi Zhang, Zhihui Bai
February 27, 2023 (v1)
Keywords: logistic time function, mining subsidence, residual subsidence, surface subsidence process
The exploitation of underground coal resources has stepped up local economic and social development significantly. However, it was inevitable that time-dependent surface settlement would occur above the mined-out voids. Subsidence associated with local geo-mining can last from several months to scores of years and can seriously impact infrastructure, city planning, and underground space utilization. This paper addresses the problems in predicting progressive residual surface subsidence. The subsidence process was divided into three phases: a duration period, a residual subsidence period, and a long-term subsidence period. Then, a novel mathematical model calculating surface progressive residual subsidence was proposed based on the logistic time function. After the duration period, the residual subsidence period was extrapolated according to the threshold of the surface sinking rate. The validation for the proposed model was estimated in light of observed in situ data. The results demon... [more]
Real-Time Charging Scheduling and Optimization of Electric Buses in a Depot
Boud Verbrugge, Abdul Mannan Rauf, Haaris Rasool, Mohamed Abdel-Monem, Thomas Geury, Mohamed El Baghdadi, Omar Hegazy
February 27, 2023 (v1)
Keywords: charging scheduling, cost analysis, depot charging, electric buses, real-time optimization
To improve the air quality in urban areas, diesel buses are getting replaced by battery electric buses (BEBs). This conversion introduces several challenges, such as the proper control of the charging process and a reduction in the operational costs, which can be addressed by introducing smart charging concepts for BEB fleets. Therefore, this paper proposes a real-time scheduling and optimization (RTSO) algorithm for the charging of multiple BEBs in a depot. The algorithm assigns a variable charging current to the different time slots the charging process of each BEB is divided to provide an optimal charging schedule that minimizes the charging cost, while satisfying the power limitations of the distribution network and maintaining the operation schedule of the BEBs. A genetic algorithm is used to solve the formulated cost function in real time. Several charging scenarios are tested in simulation, which show that a reduction in the charging cost up to 10% can be obtained under a dynami... [more]
Reviewing Explanatory Methodologies of Electricity Markets: An Application to the Iberian Market
Renato Fernandes, Isabel Soares
February 27, 2023 (v1)
Keywords: autoregressive, electricity market, GARCHX, LASSO, linear regression, Machine Learning
In this paper, for the data set of the Iberian Electricity Market for the period 1 January 2015 to 30 June 2019, 19 different models are considered from econometrics, statistics, and artificial intelligence to explain how electricity markets work. This survey allows us to obtain a more complete, critical view of the most cited models. The machine learning models appear to be very good at selecting the best explanatory variables for the price. They provide an interesting insight into how much the price depends on each variable under a nonlinear perspective. Notwithstanding, it might be necessary to make the results understandable. Both the autoregressive models and the linear regression models can provide clear explanations for each explanatory variable, with special attention given to GARCHX and LASSO regression, which provide a cleaner linear result by removing variables that have a minimal linear impact.
An Accurate Model for Estimating H2 Solubility in Pure Water and Aqueous NaCl Solutions
Zhiwei Zhu, Yuncheng Cao, Zihan Zheng, Duofu Chen
February 27, 2023 (v1)
Keywords: Hydrogen, numerical simulation, solubility
By employing a specific particle interaction theory and a high-precision equation of states for the liquid and vapor phases of H2, respectively, a new H2 solubility model in pure water and aqueous NaCl solutions is proposed in this study. The model established by fitting the experimental data of H2 solubility can be used to estimate H2 solubility in pure water at temperatures and pressures of 273.15−423.15 K and 0−1100 bar, respectively, and in salt solutions (NaCl concentration = 0−5 mol/kg) at temperatures and pressures of 273.15−373.15 K and 0−230 bar, respectively. By adopting the theory of liquid electrolyte solutions, the model can also be used to predict H2 solubility in seawater without fitting the experimental data of a seawater system. Within or close to experimental data uncertainty, the mean absolute percentage error between the model-predicted and experimentally obtained H2 solubilities was less than 1.14%.
Risk-Based Operation and Maintenance Planning of Steam Turbine with the Long In-Service Time
Martyna Tomala, Andrzej Rusin
February 27, 2023 (v1)
Keywords: M strategy, O&, risk, steam turbine, stress monitoring
In order to ensure the safety of power generation in Poland and to maintain energy production from coal-fired units with the long in-service time, it is required to develop a strategy for the further operation of the conventional power plants in conditions of increased flexibility. The presented research focuses on the critical component of the steam turbine, which is the high-pressure rotor. The methodology of the forecasting of crack propagation and growth of life-consumption processes was described, and the probability of a failure in subsequent years was estimated. The development of the identified phenomena depends mainly on the stress increases during start-ups; therefore, these increases were determined to ensure the safety of the turbine’s operation during the assumed period of operation (13 years). The permissible stress for rotor central bore (threatened with crack propagation) was 220 MPa for start-ups which were not carried out “on demand”, and for heat grooves (threatened... [more]
The Internet of Things through Internet Access Using an Electrical Power Transmission System (Power Line Communication) to Improve Digital Competencies and Quality of Life of Selected Social Groups in Poland’s Rural Areas
Wioletta Knapik, Magdalena Katarzyna Kowalska, Monika Odlanicka-Poczobutt, Marek Kasperek
February 27, 2023 (v1)
Keywords: elderly people, innovative portal, Internet of Things, PLC system, Poland, rural areas, socially vulnerable groups
In the 21st century, society has been undergoing a technology-driven transformation which heralds a new revolution that has potential to strengthen the position of an individual and community but may also lead to the marginalization of certain groups. The Internet of Things takes advantage of the technology’s potential to improve digital competencies and the quality of life in society. The purpose of this paper is to obtain information about the digital competencies and needs of contemporary seniors and pre-senior age people, as well as socially sensitive groups from Poland’s rural areas. To strength the level of internet infrastructure in rural areas, power line communication (PLC) systems that utilize high-voltage line(s) between transformer substations are presented as a cost-effective communication tool. PowerLink IP has made PLC systems today more attractive and efficient than ever before. Based on nation-wide representative surveys conducted in deliberately selected groups, we co... [more]
Techno-Economic Assessment of the Integration of Direct Air Capture and the Production of Solar Fuels
Enric Prats-Salvado, Nathalie Monnerie, Christian Sattler
February 27, 2023 (v1)
Keywords: direct air capture, Methanol, process integration, solar energy, techno-economic assessment, thermochemical cycle
Non-abatable emissions are one of the decarbonization challenges that could be addressed with carbon-neutral fuels. One promising production pathway is the direct air capture (DAC) of carbon dioxide, followed by a solar thermochemical cycle and liquid fuel synthesis. In this study, we explore different combinations of these technologies to produce methanol from an economic perspective in order to determine the most efficient one. For this purpose, a model is built and simulated in Aspen Plus®, and a solar field is designed and sized with HFLCAL®. The inherent dynamics of solar irradiation were considered with the meteorological data from Meteonorm® at the chosen location (Riyadh, Saudi Arabia). Four different integration strategies are assessed by determining the minimum selling price of methanol for each technology combination. These values were compared against a baseline with no synergies between the DAC and the solar fuels production. The results show that the most economical metha... [more]
Rockburst Intensity Level Prediction Method Based on FA-SSA-PNN Model
Gang Xu, Kegang Li, Mingliang Li, Qingci Qin, Rui Yue
February 27, 2023 (v1)
Keywords: factor analysis, probabilistic neural network, rock mechanics, rockburst intensity level prediction, sparrow search algorithm
To accurately and reliably predict the occurrence of rockburst disasters, a rockburst intensity level prediction model based on FA-SSA-PNN is proposed. Crding to the internal and external factors of rockburst occurrence, six rockburst influencing factors (σθ, σt, σc, σc/σt, σθ/σc, Wet) were selected to build a rockburst intensity level prediction index system. Seventy-five sets of typical rockburst case data at home and abroad were collected, the original data were preprocessed based on factor analysis (FA), and the comprehensive rockburst prediction indexes, CPI1, CPI2, and CPI3, obtained after dimensionality reduction, were used as the input features of the SSA-PNN model. Sixty sets of rockburst case data were extracted as the training set, and the remaining 15 sets of rockburst case data were used as the test set. After the model training was completed, the model prediction results were analysed and evaluated. The research results show that the proposed rockburst intensity level pre... [more]
Optimization of Operating Hydrogen Storage System for Coal−Wind−Solar Power Generation
Rui Yan, Yuwen Chen, Xiaoning Zhu
February 27, 2023 (v1)
Subject: Optimization
Keywords: coal–wind–solar power, energy system optimization, hydrogen storage, multi-cycle resource allocation
To address the severity of the wind and light abandonment problem and the economics of hydrogen energy production and operation, this paper explores the problem of multi-cycle resource allocation optimization of hydrogen storage systems for coal−wind−solar power generation. In view of the seriousness of the problem of abandoning wind and photovoltaic power and the economy of hydrogen production and operation, the node selection and scale setting issues for hydrogen production and storage, as well as decision-making problems such as the capacity of new transmission lines and new pipelines and route planning, are studied. This research takes the satisfaction of energy supply as the basic constraint and constructs a multi-cycle resource allocation optimization model for an integrated energy system, aiming to achieve the maximum benefit of the whole system. Using data from Inner Mongolia, where wind abandonment and power limitation are severe, and Beijing and Shanxi provinces, where hydrog... [more]
Municipal Sewage Sludge Composting in the Two-Stage System: The Role of Different Bulking Agents and Amendments
Dorota Kulikowska, Katarzyna Bernat, Magdalena Zaborowska, Magdalena Zielińska
February 27, 2023 (v1)
Keywords: compost stability, heavy metals, humic substances and humic acids, nitrification index, nutrients, sewage sludge
This study assessed the effect of different lignocellulosic amendments and bulking agents on compost stability (based on a 4 day respiration activity test, AT4, and self-heating factor, SHF) and maturity (based on the nitrification index Initr and the ratio of C in humic acids, HA, to total organic carbon, TOC, in compost, CHA/TOC). With all feedstock compositions (FCs), the share of sewage sludge was 79% (wet mass). For FC1, wood chips (13.5%) and wheat straw (7.5%) were used as bulking agents and amendments; for FC2, instead of wood chips, energy willow was added; for FC3, pine bark (13.5%) and conifer sawdust (7.5%) were used. All FCs produced stable and mature compost; however, with FC2, the thermophilic phase last 3 days longer than with the other FCs. Moreover, an AT4 value below 10 g O2/kg dry mass (d.m.) was obtained the earliest with FC2 (after 45 days, ca. 15−20 days earlier than with other FCs). With FC2, Initr below 0.5 was obtained in ca. 60 days, 10 days earlier than with... [more]
Environmental and Economic Assessment of a Novel Solvolysis-Based Biorefinery Producing Lignin-Derived Marine Biofuel and Cellulosic Ethanol
Svetlana V. Obydenkova, Lucie V. E. Defauw, Panos D. Kouris, David M. J. Smeulders, Michael D. Boot, Yvonne van der Meer
February 27, 2023 (v1)
Subject: Environment
Keywords: drop-in marine biofuel, life cycle assessment, lignin oil, multi-product biorefinery, Technoeconomic Analysis
Methanol is considered to be a viable option for reducing greenhouse gas (GHG) emissions in shipping, the second-highest emitter after road freight. However, the use of fossil methanol is insufficient to meet climate change targets, while renewable methanol is yet unavailable on a commercial scale. This paper presents a novel biorefinery concept based on biomass solvolysis to produce crude lignin oil (CLO) from forest residues, a drop-in biofuel for methanol-propelled ships, and evaluates its environmental and economic profiles. In the base scenario, CLO can achieve emission saving of 84% GHG compared to fossil alternatives, and a minimum selling price (MSP) of $821 per ton of methanol equivalent (ME), i.e., within the range of the current bio-methanol production costs. The emission of GHGs of co-produced ethanol can be reduced by 67% compared to fossil analogues. The increase of renewable electricity share to 75% is capable of shrinking emissions by 1/5 vs. the base case, while fossil... [more]
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