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The production scheduling and flexibility provision analysis are of great importance for industrial facilities to provide support for the main power grid. This study proposes a comprehensive scheduling model for an industrial pulp and paper (P&P) mill that considers the flexibility provision from steam power generation. In this model, the internal relationships between the production and consumption of electricity, steam, and pulp in the operational processes of the P&P mill are investigated. Meanwhile, the available flexibility of steam power generation is quantified and further enhanced for participation in the manual frequency restoration reserve (MFRR) market. Furthermore, a robust scheduling model that uses support vector clustering (SVC) technology is proposed to assess the impact of uncertainties in steam temperature and pressure on the available flexibility of steam power generation, thereby reducing the probability of failing to provide the contracted flexibility for MFRR. Simulation results demonstrate that the comprehensive scheduling model significantly increases the available flexibility of steam power generation for MFRR, resulting in a daily revenue increase of $1839.8. Moreover, a balance between the revenue obtained from the MFRR market and the probability of economic penalties incurred for failing to meet the contracted flexibility is achieved by comparing different levels of conservatism in the robust scheduling model. • A comprehensive scheduling model managing steam power generation is proposed. • The available flexibility of steam power generation is enhanced. • Robust scheduling is conducted considering uncertainties in steam enthalpy. • The support vector clustering technique is employed to construct uncertainty sets. [ABSTRACT FROM AUTHOR]

In the decarbonized society based on the renewable sources, the carbon fiber papers (CFPs) are regarded as key porous materials for the electrochemical energy conversion and storage devices. Searching the optimum microstructure of assembled carbon fiber paper under compression is one of the central challenges in this uprising technology. Herein, we present a tomography-based analytical approach to correlate CFP microstructures and transport parameters under the compressed state. For the sake of artificial intelligence, the prediction accuracy on the pore and solid structures is dramatically improved up to 98 % consistency when compared with the analytical solution, by identifying the true shape of cylindrical carbon fibers. The three-dimensional U-net algorithm was incorporated into the conventional X-ray computed tomography, to gain a complete separation of carbon fiber and binder. Subsequently, the origin of two different microstructures in the through-plane direction, i.e. transitional surface region and core region, are investigated as a function of compression ratio (CR). Finally, the structure-property relationship of CFP is thoroughly evaluated over a wide range of the paper thicknesses, PTFE contents and CRs. We demonstrate that the microstructural three-dimensionality, which is one decisive factor determining the transport and electrochemical properties in energy devices, can be further analysed by exploring the formation factors of solid and pore structures with increasing CRs. The insights gained from this work not only enhance the fundamental understanding of CFP microstructures but also pave the way for optimizing the design and operation of next-generation energy devices, promising a more efficient and sustainable energy landscape. [Display omitted] • AI-based tomographic method is introduced for porous energy materials such as CFP. • Digital twins of compacted CFP distinguishing pore and solid structures is realized. • Origin of core/transition region is verified by varying thickness and PTFE contents. • Binder orientation affects in-plane gas permeability in CFPs under compression. • Formation factors converged to ε2–2.5 and ε3–4 under in-plane and through-plane directions. [ABSTRACT FROM AUTHOR]

In the current study, the exergoeconomic analysis of a cogeneration pulp and paper plant under bi-operating modes at different environment temperatures of 290, 295, 305, 310, and 320 K was investigated. Two operating modes of the cogeneration system, i.e., a hybrid operating mode using a power boiler and a recovery boiler and a singular operating mode using a power boiler only, were considered. Natural gas was utilized as the main fuel in the power boiler, while black liquor with heavy fuel oil was employed in the recovery boiler. The total capital investment, total operating, exergy, unit exergy, and exergy destruction costs for each operating mode were evaluated. The results indicated that the total capital investment cost was 3420.27 $/h, and the total capital investment and the operation and maintenance costs in the hybrid and singular modes were 5853.27 and 6226.67 $/h, respectively. As well, the unit exergy cost and the exergy cost of steam introduced by the power boiler were 39.31 $/MWh and 2503.69 $/h, respectively. Where these values for the recovery boiler were 34.69 $/MWh and 554.30 $/h, respectively. Furthermore, the exergy destruction costs at an environment temperature of 320 K for the power and recovery boilers were 1436.6 and 213.63 $/h, respectively. In the hybrid mode, the soda at a 10% concentration was recovered, with a rate of 32 t per hour desired for the cooking process in the pulp mill. In addition, the use of black liquor as a bio-fuel in the recovery boiler saved 14% of the consumption of natural gas. • Exergoeconomic analysis was performed for the pulp and paper industry. • Hybrid and singular operating modes for different ambient temperatures were studied. • Unit exergy cost, exergy cost, and exergy destruction cost were evaluated. • Using black liquor as a bio-fuel in RB saved about 14% of natural gas consumption. [ABSTRACT FROM AUTHOR]

With the surging energy price and environmental concerns, measures to improve energy efficiency have attracted increasing concerns of the manufacture sector, especially energy-intensive manufacturing industries such as tissue paper mills. Energy-efficiency scheduling, as a novel energy-efficient method, has attracted the attention of an increasing number of researchers in recent years. Drying process is the most energy-intensive production process in tissue paper mills, which has a great energy-saving potential. This paper aims to reduce the energy costs for the tissue paper mill, consisting of processing energy cost and set-up energy cost, through integrating drying process optimization with energy-efficient scheduling. First, the energy cost model and the scheduling model were built. Then, the energy cost of the drying process of every job in a given scheduling problem was optimized using particle swarm optimization (PSO). Afterwards, the energy cost was further optimized using energy-efficiency scheduling. In addition, a hybrid non-dominated sorting genetic algorithm II (NSGA-II) was utilized to solve the energy-efficiency scheduling problem. Finally, several real scheduling problems from a real tissue paper mill were addressed using the proposed approach to demonstrate its effectiveness in energy saving. The experiment result showed that there is a great energy-saving potential in the drying process, accounting for up to 12.53% of the total energy consumption. Moreover, the maximum energy saving ratio of the proposed approach could reach 9.03%. On the whole, the proposed approach can provide a new energy-saving method for tissue paper mills or other manufacturing industries. [ABSTRACT FROM AUTHOR]

Hydrothermal treatment of sludge within the pulp and paper industry can have a wide range of possible reactor solid loads for different sludge types. The objectives of this work were to determine the effect of reactor temperature and solid load on the properties of sludge hydrochar and to simulate hydrothermal treatment of sludge within a pulp and paper mill. Laboratory experiments were first performed within reactor temperature and solid load ranges of 180–260 °C and 10–50%, respectively, and the effects of sludge treatment were determined by comparing parallel mill-scale simulations. Based on the results, both reactor temperature and solid load had a statistically significant effect on the solid, ash, carbon and energy yields of sludge hydrochar. Increasing solid load minimized carbon dissolution to the liquid phase and increased the solid and energy yield of the attained hydrochar. According to mill-scale simulations in a 9 m 3 batch reactor, treating primary sludge alone produced an energy surplus of 22–36 GJ through char incineration, decreasing to 12–22 GJ and 3.4–9.1 GJ for mixed and secondary sludge, respectively. Mixing primary and secondary sludge reduced the overall energy surplus by 2–8% compared with treating the sludge streams separately in two reactors. [ABSTRACT FROM AUTHOR]

• This is a case study of a small modular reactor supplying steam and electricity to a pulp and paper mill. • Resulting steam conditions in the mill are analyzed using steady-state and dynamic models. • Models of the paper mill were built in Aspen HYSYS and Dymola, a Modelica Ecosystem. • Integrated SMRs with pulp and paper mills is feasible but may present cost limitations. Small modular reactors (SMRs) are reactor designs producing less than 300 MWe and are generally planned for deployment as multimodule nuclear power plants. The possibility of factory-manufactured, flexibly sized plants expands the opportunities for nuclear power to different communities and industries, including manufacturing plants that currently utilize fossil fuels to produce both steam and electricity. This paper examines the feasibility of coupling a NuScale SMR with a midsize pulp and paper mill in the Southeastern United States. A steady-state mill model was developed in Aspen HYSYS, based on real data from the operation of the mill, and modified it to include the SMR while maintaining steam quality requirements and making as few changes as possible to existing equipment. Dynamic plant models were also developed Dymola to demonstrate possible plant conditions, using three configurations. Preliminary results suggest that, while SMR coupling is physically feasible, its economic feasibility is limited by the differences in steam and electricity demands. Because of limitations in the amount of steam the mill can take from the SMR, sizing the SMR for the plant's steam demand may result in an electricity deficit, or vice versa. Dynamic analyses show that the addition of a thermal storage system could reduce such deficits, but this entails its own challenges. Each plant must determine the best configuration and control scheme for itself, based on its electricity and heat needs, including the peak duration and intensity for both. Ultimately, an implementation of SMRs with manufacturing processes would benefit from partnering with a local utility to purchase excess electricity generated by the SMR. This will help manufacturing facilities meet their environmental and cost-savings goals, in addition to meeting the need for cost-effective baseload power across the United States. [ABSTRACT FROM AUTHOR]

Abstract: The two main wastes generated from secondary fibre paper mills are rejects (composed mainly of plastics and fibres) and de-inking sludge, both of which are evolved from the pulping process during paper manufacture. The current practice for the disposal of these wastes is either by land-spreading or land-filling. This work explores the gasification of blends of pre-conditioned rejects and de-inking sludge pellets with mixed wood chips in an Imbert type fixed bed downdraft gasifier with a maximum feeding capacity of 10kg/h. The producer gases evolved would generate combined heat and power (CHP) in an internal combustion engine. The results show that as much as 80wt.% of a brown paper mill’s rejects (consisting of 20wt.% mixed plastics and 80wt.% paper fibres) could be successfully gasified in a blend with 20wt.% mixed wood chips. The producer gas composition was 16.24% H2, 23.34% CO, 12.71% CO2 5.21% CH4 and 42.49% N2 (v/v%) with a higher heating value of 7.3MJ/Nm3. After the removal of tar and water condensate the producer gas was of sufficient calorific value and flow rate to power a 10kWe gas engine. Some blends using rejects from other mill types were not successful, and the limiting factor was usually the agglomeration of plastics present within the fuel. [Copyright &y& Elsevier]

Abstract: The pulp and paper industry both uses and produces large amounts of energy and rising fuel prices bring along significant challenges to the sector. Several strategies can be applied in order to remain competitive e.g. an increase in energy efficiency, a switch in fuel and/or a novel energy conversion technology. In this study, we investigate if improved energy conversion strategies can reduce energy costs, primary energy use and CO2 emissions of paper mills within different European countries (The Netherlands, Poland and Sweden). Our results show that differences in history and availability of resources has led to different conversion strategies in the three countries. We found that a natural gas combined cycle, which is largely implemented in The Netherlands due to long term domestic availability of natural gas, has the lowest primary energy demand. Due to a long history of low electricity prices, CHP has not been common in Sweden. Many Swedish mills use biomass as an energy source and due to low CO2 emissions of the national grid the CO2 emission profile of the Swedish paper industry is very low. Our results imply that future conversion routes for the Swedish paper and board industry are again wood based; in case of increasing electricity prices these would be biomass gasification based CHP solutions. With a reduction of 800kg CO2/ton paper on average, a switch from coal to biomass would reduce CO2 emissions in the Polish pulp and paper industry with approximately 0.6Mton/year. A carbon price of 20–25€/ton would, according to our results, be enough to provoke this switch. Due to the high share of natural gas, the CO2 emission reduction potential of the Dutch paper industry (1.5Mton/year) is even larger than in Poland. Due to high biomass prices and relative low CO2 emission profile of natural gas, a carbon prices of more than 60€/ton CO2 would be needed to provoke a switch in The Netherlands. Provided with few alternatives, the most effective strategy in The Netherlands would be an increase in energy efficiency. [Copyright &y& Elsevier]

To address the growing need for economically viable sludge processing technologies and associated resource recovery, a novel convective high-velocity pilot cyclone was set-up at the Swedish University of Agricultural Sciences in Umeå, Sweden. In essence this process entails feeding (⩽900 kg h −1 ) a material to a heated high-velocity air flow (approx. 13 × 10 3 m 3 h −1 ) allowing moisture removal at low temperatures. This equipment is expected to improve drying of challenging industrial sludge materials when used as a pretreatment method prior to further processing. Modeling results based on an experimental campaign on recycled paper mill sludge indicated that efficient drying with a specific energy consumption of ⩽1–1.2 kWh kg −1 H 2 O can be achieved with inlet air temperature levels ⩾40 °C coupled with respective feeding capacity of ⩽750 kg h −1. [ABSTRACT FROM AUTHOR]

Abstract: A great interest has been arising about the production of fuels and advanced chemicals from renewable resources such as wooden biomass in the so-called biorefineries. Pulp and paper mills are often seen as the most obvious fundamental module of such industrial sites, because of the common feedstock and the chemical transformations that already occur in the process. In this paper the model of real Kraft pulp and paper mill is developed and optimized from energetic point of view using process integration techniques, in order to assess the potential for energy saving and to establish a starting point for future research on biorefinery sites. Improvements to the configurations of the multi-effect evaporator and of the steam cycle in the CHP system have been introduced, and three different levels of heat integration boundaries have been considered (multi-effect evaporator, mill sub-processes, and total site). Results indicate a significant potential for the decrease in thermal energy requirement and/or the increase in power production for the same pulp and paper production. [Copyright &y& Elsevier]

Abstract: The pulp and paper industry is one of the most energy-intensive industries worldwide. In 2007, it accounted for 5% of total global industrial energy consumption and 2% of direct industrial carbon dioxide (CO2) emissions. An energy audit is a primary step toward improving energy efficiency at the facility level. This paper describes a plant-wide energy audit aimed at identifying energy conservation and CO2 mitigation opportunities at a paper mill in Guangdong province, China. We describe the energy audit methods, relevant Chinese standards, methods of calculating energy and carbon indicators, baseline energy consumption and CO2 emissions of the audited paper mill, and nine energy-efficiency improvement opportunities identified by the audit. For each of the nine options, we evaluate the energy conservation and associated CO2 mitigation potential. The total technical energy conservation potential for these nine opportunities is 967.8terajoules (TJ), and the total CO2 mitigation potential is equal to 93,453tonnes CO2 annually, representing 14.4% and 14.7%, respectively, of the mill’s total energy consumption and CO2 emissions during the audit period. [Copyright &y& Elsevier]

Abstract: The systematic, transparent and accurate on-line energy information of the production process is quite the basis of mill energy management and conservation. An Energy Management System (EMS) was built according to the characteristics of the energy usage in a typical newsprint paper mill. The EMS first realized the process data acquisition and integration, second fulfilled the on-line energy information calculation from the integrated data. A water and steam properties query component based on IAPWS-IF97 was developed and plugged into the EMS to facilitate the energy calculation of water and steam. The practical performance in the paper mill showed that the integrated energy information of the whole mill was gained and the on-line energy supervisory was achieved. In the end a systematic, transparent and accurate energy usage profile is obtained and it would provide the valuable fundamental energy data for the further energy analysis and optimization in the EMS. [Copyright &y& Elsevier]

Abstract: Alarmingly low pulp prices in early 2009 left pulp and paper mills across North America desperate for any way to improve thin profit margins. One solution that continues to gain popularity among the industry is improved energy management systems for cogeneration systems, which use steam for two purposes – to provide heat for the pulping process and to generate electricity for sale to regional providers. This paper presents an energy optimization algorithm for use in a pulp and paper mill cogeneration system. The algorithm is applicable to a number of popular mill configurations, power sale contracts, and fuel purchasing scenarios. The method is also extended to address weather-dependent cooling limitations encountered by a mill cogeneration facility, in which case an iterative solution is proposed in order to maintain convexity of the optimization problem. Results are presented in the form of three case studies. [ABSTRACT FROM AUTHOR]

Abstract: As a significant fraction of municipal solid waste, waste paper is a potential source for producing bioethanol. In the present paper, bioethanol production from various waste papers (newspaper, office paper, cardboard and magazine) using an enzyme complex (Cellic Ctec 1) was evaluated from an economic standpoint. Four bases cases without pre-treatment and two state-of-the-art cases (including dilute acid pre-treatment for office paper and oxidative lime pre-treatment for newspaper) were constructed using laboratory experimental data, literature values, expert consultations and simulation using AspenPlus™. Several scenarios were also carried out to assess the sensitivity of various technology parameters (i.e. solids loading in saccharification, anaerobic digestion and fermentation efficiency, and sugar yields in pre-treatment). The sensitivity analysis suggested that the economic performance of bioethanol produced from waste paper could be improved significantly with an up to 25% reduction in minimum ethanol selling price (MESP) by increasing solids loading in saccharification and with a 6% reduction in MESP by enhancing fermentation efficiency. The comparison of the bioethanol selling price at pump (reference year 2009) and the petrol price showed bioethanol produced from newspaper, office paper and cardboard were economically competitive with petrol. [Copyright &y& Elsevier]

Abstract: Waste papers (newspaper, office paper, magazines and cardboard in this study) with 50–73% (w/w oven dry weight) carbohydrate contents have considerable potential as raw materials for bioethanol production. A particle size reduction step of wet blending prior to enzymatic hydrolysis of newspaper was found to increase the glucan conversion efficiency by up to 10%. High-solids loading hydrolysis at 15% (w/w) of four types of paper using two enzyme alternatives, Celluclast 1.5L supplemented with Novozyme 188 and Cellic Ctec 1 (Novozymes A/S, Demark), at various enzyme concentrations were successfully performed in a lab-scale overhead-stirred reactor. This work has identified the relative saccharification performance for the four types of paper and shows office paper and cardboard to be more suitable for producing bioethanol than newspaper or magazine paper. The experimental data were also very well described by a modified, simple three parameter glucan and xylan hydrolysis model. These findings provide the possibility for incorporating this validated kinetic model into process designs required for commercial scale bioethanol production from waste paper resources. [Copyright &y& Elsevier]

The pulp and paper industry is a high energy consuming and polluting sector, and carbon emissions emitted from this sector are worthy of attention. This article, based upon an analysis of China’s Pulp and Paper Industry (CPPI), provides estimates of each of the following: carbon emissions from energy consumption, pre-treatment sector, combustion of condensed black liquor, and methane emitted from incomplete aerobic digestion during sewage treatment of CPPI. During the study period (2005–2012), total CO 2 emissions ranged from 126.0 Mt to 155.4 Mt. Energy consumption was estimated to be the largest source of carbon emissions, however, due to the application of the local emission inventory rather than the IPCC inventory, energy consumption decreased by 4.7%, a lower percentage than was calculated in a previous study. According to this study’s estimation, the emissions caused by the recovery of biomass energy contributed 26–29% of the total CO 2 emissions. CH 4 generated from sewage treatment accounted for 9–11% of the total carbon emissions. The CO 2 intensity dropped during the study period, which reflected the improvement of energy efficiency in the pulp and paper industry. The outcome of this study provides not only detailed information about CPPI’s carbon emissions, but also a calculation framework for studying carbon emissions from pulp and paper sector in the other regions. It suggests that the local carbon emissions inventory should be used for estimating carbon emissions and to reduce the fossil fuel energy, increase energy recovery from biomass, and that promoting cleaner production is essential to achieve a low carbon development of the pulp and paper industry. [ABSTRACT FROM AUTHOR]

Highlights • Pyrolysis and gasification of different paper-polystyrene mixtures investigated. • TGA results revealed delayed polystyrene decomposition in paper waste presence. • Synergistically doubled gas yield using co-pyrolysis and 15% using co-gasification. • Energy yield via syngas increased by 30% using CO 2 co-gasification of mixtures. Abstract Co-pyrolysis and CO 2 co-gasification of paper and polystyrene blends in different mixture ratios were studied at 1173 K using a laboratory scale tube reactor and thermogravimetric analysis. The chemical composition and yield of the syngas produced was analyzed by a micro gas chromatograph to understand the influence of mixture components. Co-pyrolysis positively impacted the syngas yield exhibiting a synergistic influence on cracking reactions leading to increased gaseous yield having almost double the amounts of hydrogen yield. Co-gasification using CO 2 increased the total gas yield with enhanced synergistic conversion. This effect provided a non-linear impact on the combustible gases in the gaseous yields when compared to the separate gasification of these feedstocks. The synergistic enhancement of co-pyrolysis conversion in paper-polystyrene led to lower char present for CO 2 to react during CO 2 co-gasification that lead to lower CO during the gasification of this blended char residue. The mixtures of paper with polystyrene provided increased product gas yields and enhanced conversion with an increase in polystyrene content. The results showed the effectiveness of producing high energy density syngas from co-gasification which can alleviate material handling issues present in segregation of waste, such as plastics and biomass providing uniform valuable product from diverse waste feedstocks with minimal need for classification. [ABSTRACT FROM AUTHOR]

Due to the increased use of variable renewable energy sources, more capacity for reserves is required. Non-generating resources such as large industrial consumers can arbitrage energy prices and provide reserve capacity by exploiting the inherent flexibility in selected industrial processes. A large enough industrial consumer can capitalize on this flexibility through optimized bidding in electricity markets. In this work, the day-ahead cost minimization of a risk-averse pulp and paper mill is formulated as a two-stage stochastic problem, considering thermodynamic and electrical constraints. The bids in the energy and reserve markets are jointly optimized subject to price uncertainty as well as uncertainty of frequency realization. The results of a case study in Sweden display a significant economic benefit in exploiting the flexibility of integrated pulp and paper mills with electric boilers. The expected cost of the pulp and paper mill resulting from different strategies are compared and the risk-aversion of the pulp and paper mill is investigated. Reserve offers are mainly facilitated by fast-acting electric boilers and supported by flexibility in the steam network. We show that reserve offers can significantly improve the profitability of the pulp and paper mill. • Pulp and paper mills with electric boilers can supply primary frequency reserves. • Electric boilers can provide up to 50 MW flexibility of 100 MW rating. • An algorithm is developed to optimize the energy & reserve bids of the mill. • Expected cost savings range between 7.4% in summer and 2.3% in winter. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Stepwise pyrolysis at 350 and 500 °C can separate products into two fractions. • First step liquid product was acidic and had high amounts of oxygenated compounds. • Products from the second step had high hydrocarbon contents and low acidity. • Interaction between cellulose and plastics during stepwise pyrolysis was observed. • Test on real wastes and discussion of scaling-up possibilities were presented. Abstract Mixed plastics and papers are two of the main fractions in municipal solid waste which is a critical environmental issue today. Recovering energy and chemicals from this waste stream by pyrolysis is one of the favorable options to achieve a circular economy. While pyrolysis products from plastics are mainly hydrocarbons, pyrolysis products from paper/biomass are highly oxygenated. The different nature of the two pyrolysis products results in different treatments and applications as well as economic values. Therefore, separation of these two products by multi-step pyrolysis based on their different decomposition temperatures could be beneficial for downstream processes to recover materials, chemicals and/or energy. In this work, stepwise pyrolysis of mixed plastics and paper waste was performed in a batch type fixed bed reactor using two different pyrolysis temperatures. Neat plastic materials (polystyrene, polyethylene) and cellulose mixtures were used as starting materials. Then, the same conditions were applied to a mixed plastics and paper residue stream derived from paper recycling process. The condensable products were analyzed by GC/MS. It was found that pyrolysis temperatures during the first and second step of 350 and 500 °C resulted in a better separation of the oxygenated and hydrocarbon condensates than when a lower pyrolysis temperature (300 °C) was used in the first step. The products from the first step were derived from cellulose with some heavy fraction of styrene oligomers, while the products from the second step were mainly hydrocarbons derived from polystyrene and polyethylene. This thus shows that stepwise pyrolysis can separate the products from these materials, although with some degree of overlapping products. Indications of interaction between PS and cellulose during stepwise pyrolysis were observed including an increase in char yield, a decrease in liquid yield from the first temperature step and changes in liquid composition, compared to stepwise pyrolysis of the two materials separately. A longer vapor residence time in the second step was found to help reducing the amount of wax derived from polyethylene. Results from stepwise pyrolysis of a real waste showed that oxygenated and acidic products were concentrated in the liquid from the first step, while the product from the second step contained a high portion of hydrocarbons and had a low acid number. [ABSTRACT FROM AUTHOR]

Abstract: Evolutionary behavior of syngas chemical composition and yield have been examined for paper and cardboard at three different temperatures of 800, 900 and 1000°C using CO2 as the gasifying agent at constant flow rate. Specifically the evolution of syngas chemical composition with time has been investigated. Pyrolysis of the sample was dominant at the beginning of the gasification process as observed from the high initial devolatilization of the sample followed by char gasification of material to form syngas for a long period of time. Results provided the role of gasification temperature on kinetics of the CO2 gasification process. Increase in gasification temperature provided increased conversion of the sample material to syngas. Thus the sample conversion to syngas was low at the low temperature of 800°C while at elevated temperatures of 900 and 1000°C substantial enhancement of the kinetics process occurred. The evolution of extensive reaction rate of carbon-monoxide was calculated. Results show that increase in temperature increased the extensive reaction rate of carbon-monoxide. The global behavior of syngas chemical composition examined at three different temperatures revealed a peak in concentration of H2 to exhibit after few minutes into the gasification that changed with gasification temperature. At 800°C gasification temperature peak in H2 was displayed at 3min into gasification while it decreased to only 2min, approximately, at gasification temperatures of 900 and 1000°C. The effect of reactor temperature on CO mole fraction has also been examined. Increase in the gasification temperature enhances the mole fraction of CO yields. This is attributed to the increase in forward reaction rate of the Boudouard reaction (). The results show important role of CO2 gas for the gasification of wastes and low grade fuels to clean syngas. [Copyright &y& Elsevier]

Abstract: With the final aim of reducing the energy consumption and increase the methane production at Swedish pulp and paper mills, the methane potential of 62 wastewater effluents from 10 processes at seven pulp and/or paper mills (A–G) was determined in anaerobic batch digestion assays. This mapping is a first step towards an energy efficient and more sustainable utilization of the effluents by anaerobic digestion, and will be followed up by tests in lab-scale and pilot-scale reactors. Five of the mills produce kraft pulp (KP), one thermo-mechanical pulp (TMP), two chemical thermo-mechanical pulp (CTMP) and two neutral sulfite semi-chemical (NSSC) pulp. Both elementary and total chlorine free (ECF and TCF, respectively) bleaching processes were included. The effluents included material from wood rooms, cooking and oxygen delignification, bleaching (often both acid- and alkali effluents), drying and paper/board machinery as well as total effluents before and after sedimentation. The results from the screening showed a large variation in methane yields (percent of theoretical methane potential assuming 940NmL CH4 per g TOC) among the effluents. For the KP-mills, methane yields above 50% were obtained for the cooking effluents from mills D and F, paper machine wastewater from mill D, condensate streams from mills B, E and F and the composite pre-sedimentation effluent from mill D. The acidic ECF-effluents were shown to be the most toxic to the AD-flora and also seemed to have a negative effect on the yields of composite effluents downstream while three of the alkaline ECF-bleaching effluents gave positive methane yields. ECF bleaching streams gave higher methane yields when hardwood was processed. All TCF-bleaching effluents at the KP mills gave similar degradation patterns with final yields of 10–15% of the theoretical methane potential for four of the five effluents. The composite effluents from the two NSSC-processes gave methane yields of 60% of the theoretical potential. The TMP mill (A) gave the best average yield with all six effluents ranging 40–65% of the theoretical potential. The three samples from the CTMP process at mill B showed potentials around 40% while three of the six effluents at mill G (CTMP) yielded 45–50%. [Copyright &y& Elsevier]

Abstract: The transport of electrons through the gas diffusion layer (GDL) of polymer electrolyte membrane (PEM) fuel cells has a significant impact on the optimal design and operation of PEM fuel cells and is directly affected by the anisotropic nature of the carbon paper material. In this study, a three-dimensional reconstruction of the GDL is used to numerically estimate the directional dependent effective electrical conductivity of the layer for various porosity values. The distribution of the fibers in the through-plane direction results in high electrical resistivity; hence, decreasing the overall effective electrical conductivity in this direction. This finding is in agreement with measured experimental data. Further, using the numerical results of this study, two mathematical expressions were proposed for the calculation of the effective electrical conductivity of the carbon paper GDL. Finally, the tortuosity factor was evaluated as 1.7 and 3.4 in the in- and through-plane directions, respectively. [Copyright &y& Elsevier]

Abstract: This paper presents the application of a comprehensive approach to the design of small scale sustainable distributed generation systems with special focus on energy recovery from paper production process sludge. The methodology integrates a detailed fluid-dynamic analysis tool with preliminary experimental analysis on a laboratory scale to guide the design of a prototype bubbling fluidized bed gasifier in the 85kW power range fitting with small and medium size paper production industries. Preliminary tests show stable operation even for this rather small power scale, and deviation from chemical equilibrium concentration in agreement with literature available data. Energy content in the sludge may be recovered along with a significant reduction of residual volume and mass. The concept may then be used to increase the overall sustainability of paper production. [Copyright &y& Elsevier]

Abstract: This paper studies allocation of fuel costs and CO2-emissions to heat and power in a CHP plant producing heat to an integrated pulp and paper mill and electricity to the liberalized electricity markets (or to the mill by the market price). The CHP plant and the mill are considered to be two separate economical units and both the mill and the CHP plant perspectives are discussed. Fuel costs and CO2-emissions are allocated using the energy, exergy and market based methods. The CHP plant purchases black liquor and bark from the mill. It also purchases oil from the markets to cover the whole fuel demand of the plant. The results indicate that the marked based method can be recommended as a “neutral” cost allocation method, because with that, the energy producer is not collecting extra margins from selling steam. This means that heat pricing is cost based. The results also indicate that depending on the emission factor and efficiency of alternative energy production form, the marked based method or the exergy method allocate the lowest CO2-emissions to heat. Therefore, the use of market based method for allocating costs and CO2 emissions can be recommended in order to use one single approach in both. [Copyright &y& Elsevier]

Increasing the conductivity of gas diffusion layers (GDLs) is an important way to improve the output performance of polymer electrolyte membrane fuel cells (PEMFCs). However, the complex porous fiber structures of GDLs significantly enhances the difficulty of quantitatively altering their conductivity which is determined by the carbon fibers and the conduction characteristics between fibers. In addition, the microstructures of various types of GDLs are different. Thus, it is a considerable challenge to explore the conductive mechanisms of these porous materials and optimize their structures to reduce their bulk resistances. In this work, a mathematical graph theory model that applies to the through-plane (T-P) bulk resistance prediction of two types of commonly used GDLs, carbon paper and carbon felt, is established to explain their different micro conduction mechanisms in depth. In addition to the number of fiber contact points, their distribution, as well as the resistance of the carbon fibers, are all important factors affecting the T-P conductivity. Optimizing fiber density and fiber diameter can significantly improve the T-P conductivity of carbon paper. In comparison, making the structure of carbon felt more compact so that the distribution of its contact points in the T-P direction can be more uniform will be more effective for the reduction of its T-P bulk resistance. Meanwhile, the T-P bulk resistance of carbon paper can also be effectively improved by optimizing the content and distribution of the binders. A method to decline the bulk resistance of carbon paper by aggregating the binders in the in-plane (I P) direction is proposed. The simulation results show that it can reduce the T-P bulk resistance of carbon paper by about 19.9% at a compressive stress of 1.5 MPa. This study provides further guidance for optimizing the structural designs of GDLs to optimize their conduction performance. • T-P bulk resistance prediction model suitable for different GDLs is constructed. • Micro conductivity mechanisms of carbon paper and carbon felt are compared. • Increasing fiber density and diameter improves carbon paper's T-P conductivity. • Making carbon felt's structure more compact can optimize its T-P conductivity. • To promote carbon paper's T-P conductivity by optimizing the binders inside. [ABSTRACT FROM AUTHOR]

[Display omitted] • New biocathode including BOD, 4-APA, and BP electrode (BP/4-APA/BOD is suggested. • The biocathode is prepared by electrografting method. • Membraneless paper type EBFCs using this biocathode are fabricated. • This paper type EBFC is well operated even in a condition of living body fluid. • OCV/MPD of this paper type EBFC are 0.612 ± 0.002 V/92.025 ± 0.892 μW cm−2. A new biocathode consisting of bilirubin oxidase (BOD), 4-aminophthalic acid (4-APA) and buckypaper (BP) electrode is suggested for enzymatic biofuel cells (EBFCs). Here, to enhance the electron transfer rate of BOD, electrografting method is imported. When this method and 4-APA are utilized, BP surface has negative charges by the polarity arrangement of 4-APA, forming BP/4-APA structure. With the modification of surface charge, T1 active site within BODs having positive charges are strongly bonded with the negative charges of BP/4-APA in neutral pH condition, while the orientation of T1 site is well aligned by electrostatic interaction. This treatment increases both reactivities of cathodic reaction and EBFC performance. To prove that, the performance of membraneless paper-type EBFCs using the new flexible BP/4-APA/BOD biocathode is investigated. According to the evaluations, their maximum power density and open circuit voltage are 92.025 ± 0.892 μW cm−2 and 0.612 ± 0.002 V with injection of 10 mM glucose which is a condition of living body fluid. Such performances are far better than those of other membraneless EBFCs and are large enough to be utilized as a power source of implantable devices for the human body. [ABSTRACT FROM AUTHOR]

• A paper-based Al-air battery successfully developed for miniwatt applications. • The battery can work with limited electrolyte supply without external pumping. • Low-cost and low-grade Al employed with satisfactory discharge efficiency. • The paper substrate suppresses the Al self-corrosion with alkaline electrolyte. • An efficient and modular stacking strategy for battery pack development. Conventional Al-air battery is not suitable for mini-watt applications due to bulky liquid storage and complex water management. To achieve successful simplification and miniaturization, an innovative paper-based Al-air battery is developed in this study, which employs cellulose paper as electrolyte substrate, low-grade Al foil as anode and carbon paper as cathode. Despite its simple structure and low cost, this battery achieves satisfactory power output together with high efficiency. With alkaline electrolyte, an open-circuit voltage of 1.6 V, a peak power density of 21 mW cm−2 and a specific capacity of 1273 mA h g−1 are obtained. With saline electrolyte, the battery can continuously work at 1 mA cm−2 for 5.6 h with only 3.5 mg Al. In addition, it is found that the paper-based electrolyte delivery can suppress Al corrosion in alkaline environment, enabling the direct utilization of low-grade Al resources. Moreover, the battery performance is improved by optimizing properties of its components, such as cathode catalyst, electrode area ratio and paper substrate thickness. Finally, a 5-cell battery pack is successfully developed, achieving an open-circuit voltage of 7.7 V and a stacking efficiency as high as 97%. By further scaling-up, this battery pack is successfully demonstrated for charging portable electronics. [ABSTRACT FROM AUTHOR]

Abstract: Densified biomass pellets using waste wood sawdust (S) as main materials and wrapping paper fiber (P) as “solid bridge”, named as P/S-BPs, was prepared by a hydraulic press powder pelletizer under room temperature and pressure lower than10MPa. The effects of the addition of P to S and the compressed pressure on the density, resiliency (R), abrasion resistance (AR), impact resistance index (IRI)) and the combustion behavior of the P/S-BPs were investigated. The results showed that the addition of P to S greatly reduced the negative effects of resiliencies on the densities and mechanical properties of P/S-BPs during storage. For example, P/S-BPs compressed at 6MPa in a P/S mass ratio of 1–3 showed the smooth surface and low resiliency of 10% with a high relaxed density of 1.08kgm−3. This is due to the strengthened interlocking bonds through fabricating “solid bridge” and increasing attracting force by adding P to resist the disruptive force created by elastic recovery even under low pressure. Combustion results showed that the addition of P decreased the soot index (SI) due to the lower devolatilization rate and burnout rate, and increased the HHV per unit volume because of its high relaxed density. Thus, compression of waste P and S in a P/S mass ratio of 1–3 at room temperature under 6MPa is a cost-effective process to produce densified sustainable bio-fuel from waste S and P as well as dispose them. [Copyright &y& Elsevier]

Abstract: A detailed mathematical process integration model of a pulp and paper mill in the Northern Sweden has been developed. The main objective of this work has been set to describe the practical development of the model with particular emphasis on the development of the digester and evaporation plant sub-models. Actual plant measurements have been used to validate the model. By implementing the sub-models into the complete plant model, the influence of different operation parameters on the overall plant performance has been investigated. Furthermore, introductory studies with the main objective to minimize the plant energy cost have been carried out. [Copyright &y& Elsevier]

Abstract: The thermal behavior of semi-anthracite coal, paper sludge and their blends during pyrolysis and combustion processes was investigated in this study. The experiments were conducted in a differential thermogravimetric analyzer at different heating rates (10K/min, 20K/min and 30K/min) and at temperatures ranging from 310K to 1300K. The results revealed that de-volatilization of paper sludge occurred earlier with a higher rate, and that the process was further accelerated under oxygen-enriched conditions. The blends had integrative thermal profiles that reflected both paper sludge and coal. In addition, the blends showed different ignition and combustion behavior depending on the percentage of sludge. Two types of non-isothermal kinetic analysis methods were applied to evaluate the combustion processes. The kinetic parameters of the blends confirmed the improved ignition characteristics. In addition, both the TG profiles and activation energy indicated that the combustion of their blends with low percentages of sludge, such as 10 wt.%, were similar to that of coal. These experimental results help explain and predict the behavior of coal and paper sludge blends in practical applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • A H 2 O 2 paper fuel cell with hydrogel-aided dual electrolytes has been developed. • High performance is achieved by toning the alkaline-acid dual electrolytes. • Firstly investigate the electrochemical reaction mechanisms via radical analysis. • The fuel cell shows excellent performance of ∼ 10 mW cm−2 and the best durability. Cellulose paper has been employed to develop pumpless microfluidic fuel cells. Meanwhile, hydrogen peroxide as both the fuel and oxidant has attracted attention since it is eco-friendly for producing only water. However, low open-circuit voltage (OCV) and power density of reported H 2 O 2 fuel cells due to the mixed potentials (simultaneous oxidation and reduction at the same electrode) preclude its applications. In this study, a H 2 O 2 paper fuel cell with a gel-aided dual-electrolyte configuration has been proposed for the first time to solve this problem. An ion-conductive hydrogel has been sandwiched between the independent catholyte and anolyte flows to serve as part of the electrolyte. Its OCV has been elevated to 1 V and a high peak power density of 10.2 mW cm−2 has been achieved by toning the electrolytes, which exceeds most reported H 2 O 2 fuel cells. The results demonstrate that alkaline anolyte benefits the cell performance more significantly than acidic catholyte does. The reaction mechanism at each electrode was further studied to provide insights for future development of H 2 O 2 fuel cells: the reduction at the cathode follows the Fenton reaction; as for the oxidation at the anode, it was first revealed that H 2 O 2 oxidation was facilitated by free radicals generated from H 2 O 2 in alkaline media. Besides, the radicals also help to maintain a large voltage difference between the electrodes. Furthermore, this fuel cell shows great durability and can be instantly re-activated upon refueling. This gel-aided dual-electrolyte fuel cell design can pave a way for practical applications of direct H 2 O 2 fuel cells. [ABSTRACT FROM AUTHOR]

• Commercial air-laid paper and carbon ink were used for moist power generation. • The voltage of 0.35 V and current of 33.9 μA were generated in the atmosphere (6 cm2). • The power generator was designed for some extreme situations such as in the wild. • Integration of generators could power wearable electronic devices in the atmosphere. Low-grade energy harvesting from the ambient environment promises to relieve the energy shortage in the remote regions or emergency needs. The reported materials employed for low-grade energy harvesting requires costly raw materials and highly technical skills, hindering the applications in isolated regions or after natural disasters. Herein, we report the use of commercial air-laid paper and carbon ink to harvest electrokinetic energy in the capillary flow. The paper-based electrokinetic power generator with size of 6 cm × 1 cm could continuously generate an output voltage of 0.35 V and current of 33.9 μA in the ambient condition (20 °C and 50% Relative Humidity). The output power could maintain for over 120 h. When connected in series and in parallel, the power generator with excellent flexibility could power some common electronic devices in the atmosphere, such as light-emitting diode, electronic calculator and watch. This work offers a rational approach to employing low-cost materials for ambient energy harvesting, thus advancing the application in portable and wearable electronic devices. [ABSTRACT FROM AUTHOR]

Abstract: Carbon paper is commonly used as the gas diffusion layer (GDL) in polymer electrolyte membrane (PEM) fuel cells as it exhibits high chemical and mechanical durability. This diffusion medium is also anisotropic, which directly affects its transport properties and specifically the thermal conductivity. In this study, the in-plane thermal conductivity of the carbon paper GDL was determined using thermal diffusivity measurements for a temperature range from −20 to +120°C and four Teflon loadings (0, 5, 20 and 50wt.%). It is important to understand the effect of temperature on the thermal conductivity since PEM fuel cells are designed to operate under various temperatures depending on the application of use. Further, Teflon is used to change the hydrophobic properties of the carbon paper GDL with 20wt.% as the most widely used percentage. In this study, the Teflon loadings were chosen to gain a comprehensive understanding of the thermal resistance due to Teflon. In this study, a quasi-steady method was used to measure the thermal properties of the carbon paper; hence, the phase transformation in the presence of PTFE was investigated. The thermal conductivity decreases with an increase in temperature for all samples. The addition of as little as 5wt.% Teflon resulted in high thermal resistance decreasing the overall thermal conductivity of the sample. Further addition of Teflon did not have major effects on the thermal conductivity. For all treated samples, the thermal conductivity lies in the range of 10.1–14.7W/mK. Finally, empirical relations for the thermal diffusivity and conductivity with temperature were deduced. [Copyright &y& Elsevier]

Abstract: Turkish electricity market law (EML) came into force in 2001 aiming at establishing a financially strong, stable, transparent and competitive electricity market based on bilateral contracts. Also, a balancing and settlement system (BSS) was put into practice in November 2004 to create a market where uncontracted generation can be traded, and actual implementation of the BSS started on August, 1st 2006 following a 21-month virtual implementation period. However, BSS has always been criticized from its beginning as transferring excessive profits to private generation companies. The present paper analyzes the implementation of BSS and argues that current BSS not only undermines the healthy development of the electricity market in Turkey but also prevents power investments due to uncertainties it created. It concludes that since the inconsistency between the objectives of EML and results of BSS in practice is obvious, Turkish policy makers need to modify current electricity market policy in line with suggestions presented in the paper. [Copyright &y& Elsevier]

Abstract: Main characteristics of gaseous yield from steam gasification have been investigated experimentally. Results of steam gasification have been compared to that of pyrolysis. The temperature range investigated were 600–1000°C in steps of 100°C. Results have been obtained under pyrolysis conditions at same temperatures. For steam gasification runs, steam flow rate was kept constant at 8.0g/min. Investigated characteristics were evolution of syngas flow rate with time, hydrogen flow rate and chemical composition of syngas, energy yield and apparent thermal efficiency. Residuals from both processes were quantified and compared as well. Material destruction, hydrogen yield and energy yield is better with gasification as compared to pyrolysis. This advantage of the gasification process is attributed mainly to char gasification process. Char gasification is found to be more sensitive to the reactor temperature than pyrolysis. Pyrolysis can start at low temperatures of 400°C; however char gasification starts at 700°C. A partial overlap between gasification and pyrolysis exists and is presented here. This partial overlap increases with increase in temperature. As an example, at reactor temperature 800°C this overlap represents around 27% of the char gasification process and almost 95% at reactor temperature 1000°C. [Copyright &y& Elsevier]

Abstract: Chemical process simulation has proven to be an effective tool for performing a systematic and global analysis of energy systems to identify routes for maximizing the process efficiency concerning to the heat recovery. This paper shows an application of computer simulations in a Brazilian pulp mill, using two strategies for minimizing the mill energy consumption. In the first one, the overall heat transfer coefficient has been predicted for each body of the multiple effect evaporators by using continuous on-line data from the industrial plant in the black liquor recover unit. By monitoring oscillations of this heat transfer coefficient, the suitable time for washing the evaporator heat transfer surfaces can be well determined, reducing the energy loss during black liquor evaporation. In the second strategy, the liquor combustion has been simulated as function of the black liquor solids concentration to analyze its effect on the recovery boiler efficiency improvement. [Copyright &y& Elsevier]

In an era of increasing energy demands and environmental concerns, optimizing energy consumption within buildings is crucial. Despite the vast improvements in HVAC and lighting systems, plug loads remain an under-studied area for enhancing building energy efficiency. This paper studies smart plug active operating mode detection, plug-level load forecasting, and plug scheduling methodologies. This research leverages a unique dataset from the University of California, San Diego, consisting of readings from over 150 smart plugs in several office buildings for more than a year, notably during the post-Covid era. This dataset is made publicly available. A comprehensive literature review on plug, i.e. , appliances operating mode detection is presented. Novel unsupervised learning approaches are applied to identify plug operating modes. A pipeline integrating the detected modes with forecasting and scheduling is developed, aiming at building energy consumption reduction. Our findings offer valuable insights and promising results into smart plug management for energy-efficient buildings. • A novel year-long dataset of power readings from 169 office smart plugs is introduced. • The first review of plug load mode detection methods and terminology is presented. • The paper proposes an unsupervised method to identify plugs load operating modes. • The proposed smart plug scheduling pipeline reduces energy consumption by 20%. [ABSTRACT FROM AUTHOR]

• Nanogel particles for CO 2 capture with lower cycles (303–348 K) are developed. • Carbon paper as supporter shows higher CO 2 capacity, adsorption and desorption rate. • Avrami's fractional order model accurately predicts the CO 2 uptake behaviors. • The CO 2 capture process is governed by film and intraparticle diffusion resistance. • Carbon paper as supporter shows lower sensible heat and desorption activation energy. Amine-containing nanogel particles with a lower cooling and heating cycles (303–348 K), which is beneficial to limit the degradation and volatile of amine, has been developed as promising absorbents for CO 2 capture. It is extremely important to understand the CO 2 capture kinetics and mechanisms for design and operation of corresponding processes. In present work, poly tetra fluoroethylene and carbon paper were used to support the GPs by filtering and loading method. The CO 2 uptake and release performance of poly tetra fluoroethylene and carbon paper supported nanogel particles was measured. It was found that carbon paper as supporter shows higher CO 2 capacity and desorption rate. A comparison of three different kinetic models shows that carbon paper as supporter gives a more enhanced kinetic behavior. Avrami's fractional order model presents the best fit to experimental data. To further investigate the mechanism of CO 2 uptake on absorbents, interparticle diffusion model, intraparticle diffusion model and Boyd's film diffusion model were also applied. Film diffusion resistance governed the mass transfer rate of CO 2 uptake on studied absorbents at the initial CO 2 uptake stages. In the following stages, intra-particle diffusion resistance plays a major role until the equilibrium is reached. The sensible heat of carbon paper as supporter is about 25% lower than that of poly tetra fluoroethylene as supporter. The desorption activation energy obtained from the Arrhenius equation is 18 kJ/mol for carbon paper as supporter, which is 84% lower than that of the typical aqueous MEA solvent. [ABSTRACT FROM AUTHOR]

Abstract: The thermochemical conversion technique was applied in deinking sludge from the pulp and papermaking industrial to indagate the utilization of sludge biomass to energy, and the pyrolysis characteristics and pyrolytic products of deinking sludge were studied with thermogravimetric analysis (TGA) and pyrolysis coupled with gas chromatograph–mass spectrometer (Py-GC/MS). The static tubular furnace as an applied industrial research was used to study deinking sludge pyrolysis. The solid, gas and liquid of products was characterized by electron probe microanalysis (EPMA), gas chromatograph (GC) and gas chromatograph–mass (GC/MS), respectively. The results revealed that the weight-loss process of deinking sludge was a non-isothermal reaction and composed of four stages, i.e. dewater stage, volatile releasing stage, carbon burnout stage and some calcium carbonate decomposition. Pyrolytic products from deinking sludge in the static tubular furnace were comprised of the gaseous (29.78%), condensed liquid (bio-oil, 24.41%) and solid residues (45.81%). The volatiles from deinking sludge pyrolyzing were almost aromatic hydrocarbons, i.e. styrene, toluene and benzene and few acids and the solid was calcium carbonate (CaCO3) that can be reused as paper filler. Deinking sludge was converted into high-grade fuel and chemicals by means of thermochemical conversion techniques, hence, pyrolysis of paper deinking sludge had a promising development on the comprehensive utilization. [Copyright &y& Elsevier]

In the recent Comment on our paper ‘Life cycle environmental impacts of UK shale gas’ ( Applied Energy 134 (2014) 506–518), Westaway et al. ( Applied Energy , available online 20th March 2015) allege that we exaggerated the potential impacts of shale gas extraction in the UK. They first take an issue with our inclusion of worst case scenarios despite our clear declaration in several places in the paper that this is indicative of what could happen within the confines of a very ill-defined and highly variable future reality. Secondly, Westaway et al. claim that key assumptions in the modelling reflect illegal practices that would not occur, when in fact this is an exaggeration of the legal situation and these practices are still viable. This rebuttal addresses some of the claims made by Westaway et al. while welcoming further open and impartial discourse in this area. [ABSTRACT FROM AUTHOR]

It is vital to perform system analysis on integrated biomass gasification in chemical recovery systems in pulp and paper and heat and power plants for polygeneration applications. The proposed integration complements existing pulp and paper and heat and power production systems with production of chemicals such as methane and hydrogen. The potential to introduce gasification-based combined cycles comprising gas turbines and steam turbines to utilize black liquors and wood pellets also merits investigation. To perform such analysis, it is important to first build knowledge on expected synthesis gas composition by gasifying at smaller scale different types of feed stock. In the present paper, the synthesis gas quality from wood pellets gasification has been compared with black liquor gasification by means of numerical simulation as well as through pilot-scale experimental investigations. The experimental results have been correlated into partial least squares models to predict the composition of the synthesis gas produced under different operating conditions. The gas quality prediction models are combined with physical models using a generic open-source modelling language for investigating the dynamic performance of large-scale integrated polygeneration plants. The analysis is further complemented by considering potential gas separation using modern membrane technology for upgrading the synthesis gas with respect to hydrogen content. The experimental data and statistical models presented in this study form an important literature source for future use by the gasification and polygeneration research community on further integrated system analysis. [ABSTRACT FROM AUTHOR]

A comparison between different metal-doped carbonaceous anodes for air-breathing microbial fuel cells (MFCs) has been carried out in this work. In order to do that, the surface of carbon paper anodes were modified with Pt, Au and Ni. The current generated was higher when using these metal-doped anodes, exerting up to 7.4 A m −2 more than when using non-doped ones. Polarization curves results in a great performance of the Ni reaching 2.92 W m −2 at the steady state, followed by 0.99 W m −2 of the Au and 0.52 W m −2 of the Pt. Additionally, from the mathematical fitting of a model to the experimental data of a polarization curve, it was observed that the mechanism that explains the better performance of the metal doped anodes was the reduction of the mass transfer limitations. In this sense, the addition of metal on the anodes increase the threshold current density causing mass transfer limitations, reducing also the significance of the mass transfer limitations when the cells are operated under conditions in which the process is diffusion controlled. [ABSTRACT FROM AUTHOR]

• A digital hydrostatic drive solution for large utility wind turbine was proposed. • Two digital encoding schemes for a 2.5 MW hydrostatic wind turbine were developed. • A digital hydrostatic wind turbine control based on kw2 control law was proposed. • Digital hydrostatic solution improves energy production of hydraulic wind turbine. Gearbox failure is one of the major factors causing the increased downtime in modern wind turbines. This increases the turbine maintenance cost and therefore the turbine cost of energy. A hydrostatic transmission not only improves the turbine reliability through its "soft" transmission, but also eliminates the use of power converter through its continuous variable transmission function. A hydrostatic wind turbine usually employs a fixed displacement pump to drive a variable displacement motor. The variable displacement motor runs at partial displacement when the wind speed is below the rated wind speed, leading to low drivetrain efficiency. Moreover, large variable displacement motors for large utility wind turbine are not commercially available. Therefore in this paper a digital hydrostatic transmission solution for large utility wind turbine has been proposed. The large variable displacement motor was replaced by combining several fixed displacement motors and a small variable displacement motor with some digital encoding scheme. Two encoding schemes have been proposed for digital hydrostatic transmission. The modeling and design of the digital hydrostatic wind turbine were presented. A hydrostatic wind turbine control based on kw2 control law has been proposed. A dynamic simulation model of the digital hydrostatic wind turbine has been developed. The proposed digital hydrostatic drive solution has been compared with a conventional hydrostatic solution in a commercial 2.5 MW wind turbine. Simulation studies verified the feasibility and the engineering practice of the proposed digital hydrostatic drive solution. [ABSTRACT FROM AUTHOR]

Abstract: The energy use at a Swedish chemical wood-pulp mill is compared internationally and for two model mills that aim to use the most efficient available technology. The international comparison is performed between Canadian and Scandinavian pulp-mills on a general level, and on a closer level among eleven Swedish and Finnish non-integrated sulfate pulp-mills, the type of mill considered in the case study. The two model mills that are used for comparison are one Swedish and one Canadian. The Scandinavian pulp-mills are somewhat more energy efficient than the Canadian mills. Still, the variation in energy use is remarkably large among the Scandinavian mills, which indicates that the energy-saving potential is great. If all Swedish freestanding sulfate pulp-mills became as energy efficient as the most efficient Scandinavian mill, electricity savings corresponding to nearly 1% of the national electricity use would be obtained. In the model mills comparison it was found that large amounts of heat could be saved, particularly in the evaporation plant. [Copyright &y& Elsevier]

Innovations for near real-time common European balancing markets are underway to meet the flexibility needs induced by the deployment of renewables and new market agents. Never have markets and real-time network operations been run so closely on a continental scale. Our paper investigates a filtering method for integrating congestion management and near real-time markets. Reinforcement Learning is applied to add the cost of physical delivery to bid prices to advantage/disadvantage bids that reduce/create congestion. We assess the impact of this new method on market welfare and congestion management costs and show that it brings significant efficiency gains compared to no filtering or a baseline filtering methodology. • Real-time common European balancing markets are a new source of congestion. • Filtering is a pre-market congestion management method consisting of bid screening. • A continuous formulation of filtering, that modifies the merit order, is presented. • The cost of physical delivery is added to bid prices using Reinforcement Learning. • The proposed methodology increases net Social Welfare and helps maintain security. [ABSTRACT FROM AUTHOR]

The ever-increasing challenges related to water security and climate mitigation underscore the pressing need for forward-thinking systems planning tools to drive urban sustainability transitions. In this study, we propose a novel city-level multi-objective planning framework that explores the nexus between carbon trading and water management, with the aim of facilitating water-efficient urban industrial restructuring. The framework integrates cap-and-trade mechanisms into a two-layered optimization model, creating an integrated approach to optimizing carbon emissions and generating economic opportunities for improving water efficiency. To illustrate the potential application of this framework, we conducted a case study focusing on Dongguan City, a water-stressed industrial metropolis in southern China. The results illustrate potential synergies between water planning strategies and carbon trading schemes, which could be harnessed to enable targeted reductions in water usage and carbon emissions. Furthermore, our findings identify the textile, apparel, and paper products manufacturing industries as primary candidates for strategic production scale reduction, emphasizing the importance of sustained support for the development of the computer and electronic manufacturing sector as a catalyst for urban sustainability transitions. By pioneering this new nexus-based perspective, our study offers valuable insights into long-term strategic planning for a low-carbon and resource-efficient urban economy. • Synergizing carbon trading and water management within a novel integrated planning framework. • Implementing resource-efficiency-driven optimization for water- and carbon-intensive manufacturing sectors. • Gaining insights into the specific roles of key manufacturing sectors in water management and carbon trading. • Introducing carbon trading systems may help in promoting water-efficient industrial restructuring. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract: There are many factors that affect paper degradation in archives, but air temperature and humidity under inadequate storage conditions are among the most important ones. Such inadequate conditions will trigger biological, chemical and physical processes that may enhance the degradation of papers. On the other hand, users of libraries and archives, where documents are stored, require adequate indoor conditions for carrying out diverse activities. In this paper we analyze the performance of archives with regard to paper and document storage conditions, also given in terms of the Time Weighted Preservation Index (TWPI), against overall comfort conditions, according to ISO 7730 and to the Building Bioclimatic Chart. For that purpose, five different settings were chosen, corresponding to indoor and outdoor conditions of three Brazilian archives, located in diverse climatic regions (Curitiba, 25°25′S 49°16′W, Belo Horizonte, 19°56′S 43°56′W and Rio de Janeiro, 22°50′S 43°10′W). The monitoring period comprehended 12months, with a mid-term data collection. Results showed that there is a significant difference in storage conditions among different locations, even though there is a similarity in indoor thermal comfort conditions. A compromise solution should be sought between storage conditions and human thermal comfort parameters. [Copyright &y& Elsevier]

Nanowired α-MnO 2 material supported on carbon fiber paper (α-MnO 2 /CFP) is synthesized using a facile hydrothermal method for supercapacitor electrode. The α-MnO 2 /CFP material is characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and BET for its composition, structure/morphology, and BET surface area. The electrochemical properties of the α-MnO 2 /CFP electrode are studied by cyclic voltammetry (CV), galvanostatic charge/discharge and electrochemical impedance spectroscopy (EIS) in 1 M Na 2 SO 4 solution. The porous α-MnO 2 /CFP material electrode shows a high specific capacitance of 251 F g −1 at the current density of 1 A g −1 , and also exhibits a good rate capability and an excellent cycling stability. It is testified that even after 3000 cycles, the capacitance retention of the porous α-MnO 2 /CFP material electrode can still maintain over 98.9% of the capacitance at the high current density of 4 A g −1 , demonstrating its excellent cycling stability. The high electrochemical performance of the porous α-MnO 2 /CFP material nanowire electrode may be attributed to the 2 × 2 tunnel structure, high active surface area, and high porosity of the of α-MnO 2 material. [ABSTRACT FROM AUTHOR]