Search

China is the top emitter of greenhouse gases in the world. Pulp and paper industry is one of eight the strictly regulated industries about carbon emission in China. However, estimates of carbon emissions from China's pulp and paper industry have been suffered from remarkable uncertainty. It is summarized that is aroused by the inaccuracy of factors evaluating energy consumption, and the huge gap between the calculation standards for assessing energy consumption in the production process and the actual level recorded in the factories. This paper re-evaluated the carbon emission of China's pulp and paper industry from the perspective of life cycle assessment, and applied more accurate emission factors, taking account of the actual energy consumption of the production process in factories, to estimate the actual carbon emissions in maximum. It is found that the national standards about the energy consumption quota of China's pulp and paper industry is no longer applicable, and the actual energy consumption regulated in the production process is far better than the advanced level given by the national standards. The greenhouse gas emission have been seriously overestimated approximately 12.00%–56.17% by international organizations. • Life Cycle Analysis of the China's pulp and paper Industry is conducted thoroughly. • The pulp flow of China's pulp and paper Industry is analyzed. • Energy regulated in factory is far better than the national standards' required. • Carbon emissions of China's pulp and paper Industry are overestimated. [ABSTRACT FROM AUTHOR]

Abstract This study aims at to make a heuristic analysis of energy efficiency performance of Indian paper industry in a non-parametric production theoretic approach. Using the data for 2004–05 to 2013–14, radial and non-radial variants of DEA were employed to estimate energy saving potential and identify the relative position of paper industry across the states. Preliminary analysis in terms of energy intensity scores showed declining trends of energy intensity over the period of analysis for most of the states except states like Assam, Chhattisgarh, Kerala and Punjab where it does not decline much. Assuming a variable returns to scale (VRS) technology under the conditions of inherent heterogeneity and market imperfection, the slack-based measure (SBM) reported a much higher energy saving potential than reported by other measures in the study. Further by taking scale efficiency into account, the study documented the higher contribution of pure energy inefficiency in explaining the total energy inefficiency within the paper industry relative to scale inefficiency. Finally, the study recommends the propagation of energy efficiency program through a market-based and regulatory mechanism along with consolidation and technological advancement of individual units, in order to tap vast energy saving potential and thereby ensure the growth and environmental sustainability. Highlights • The paper examined the energy efficiency performance of Indian paper industry. • Both radial (BCC) and the non-radial (SBM) measures of energy efficiency, were applied. • BCC measure reported an energy saving potential of 16%. • SBM measure reported an energy saving potential of 24%, higher than BCC measure. • Scale efficiency implied the relatively higher contribution of pure energy inefficiency. [ABSTRACT FROM AUTHOR]

The present study investigates the effect on methane production from waste paper when co-digested with macroalgal biomass. Both feedstocks were previously mechanically pretreated to reduce their particle size. The study was planned according two factors: the feedstock to inoculum (F/I) ratio and the waste paper to macroalgae (WP/MA) ratio. The F/I ratios checked were 0.2, 0.3 and 0.4 and the WP/MA ratios were 0:100, 25:75, 50:50, 75:25 and 100:0. The highest methane yield (386 L kg −1 VS added ) was achieved at an F/I ratio of 0.2 and a WP/MA ratio of 50:50. A biodegradability index of 0.87 obtained in this study indicates complete conversion of feedstock at an optimum C/N ratio of 26. Synergistic effect was found for WP/MA 25:75, 50:50 and 75:25 mixing ratios compared with the substrates mono-digestion. [ABSTRACT FROM AUTHOR]

Variable renewable energy-based power is expected to increase toward a sustainable society, although the power cannot be dispatched effectively due to its intermittent nature. To accelerate renewable energy implementation, we simulated energy flows of paper mills installing wind energy and evaluated their potentials to function as energy hubs for appropriate early-stage design. We targeted 39 Japanese paper mills assumed to have thermal energy storage, wind–thermal energy converters and regional woody biomass installed, and analyzed the amount of power and heat selling and life cycle greenhouse gas emissions. The results for the paper mills were compared with conventional mills to examine effective conditions for greenhouse gas reduction. The amount of power or heat selling depended on the capacity of the paper mill and the installed equipment. Most paper mills could reduce greenhouse gas using thermal energy storage, wind energy, and woody biomass. The paper mill with the highest life cycle greenhouse gas reduction, compared with conventional mills, could achieve a 190% reduction. To function as a cogeneration energy hub, the equipment installed in paper mills should be designed according to the conditions of the paper mills and their regions. • Paper mills have potential as energy hubs by integrating variable renewable energy. • Thermal energy storage and wind–thermal energy converters were studied. • Energy flows and greenhouse gas emissions of paper mills were simulated. • Most mills could provide stable power and/or heat supplies and reduce emissions. [ABSTRACT FROM AUTHOR]

In the present study, a thermodynamic analysis of a cogeneration system in a pulp and paper industry under different operating modes i.e., singular and hybrid with a variable ambient temperature is conducted according to actual operating data. For singular operating mode, the power boiler is only employed using natural gas while for hybrid operating mode, the power boiler with the recovery boiler is employed using natural gas and black liquor as main fuels, respectively. The results show that for hybrid operating mode in comparison with the singular one, the thermal efficiency of turbine and condenser is enhanced by 1.36 and 7.7%, respectively while it is reduced by 2.8% for the power boiler. In addition, the overall thermal efficiency under singular and hybrid operating modes is 87.4 and 53.7%, respectively. For hybrid operating mode, the exergy destruction of power boiler decreases by almost 10% compared with that for the singular operating mode. Also, at hybrid operating mode, the soda is recovered with a mass flow rate of 33 tons/hour that is required for the cooking process in the chemical pulp section and additionally the consumption of natural gas in the power boiler is reduced by 11.8%. [ABSTRACT FROM AUTHOR]

Increasing levels of variable renewable energy require additional flexible resources in the global energy system. In countries with energy-intensive industries, flexibility may be increased through industrial demand side management (IDSM). In most studies, the potential of IDSM is estimated from a technical or theoretical viewpoint. However, IDSM capacity is only utilized if the industry finds it profitable, and thus the economic potential should also be assessed. The focus of this paper is on the intra-day IDSM potential of a paper mill site that is active in the Nordic power market. An optimization model is built to estimate the costs that occur when the paper mill executes regulating power bids, if the original production schedule has been optimized against a spot price forecast. The costs are estimated for different sizes of bids and a marginal cost curve is provided for pricing them. Using this marginal cost curve, the market potential of the case mill site is assessed. It is found that this potential is greatly influenced by the costs of executing regulating power bids. The results indicate that transmission system operators and policy makers should account for economic factors when assessing the potential of market based IDSM. [ABSTRACT FROM AUTHOR]

Long term annual electricity consumption forecasting is very important for country's energy planning. These forecasts are influenced by several factors (political, technological, social, environmental and economic), and brings with itself a high uncertainty degree in its results and difficulties in the evaluation of such factors over them. A methodology that eases to take into account these factors aiming improve the results and help understanding the electricity consumption annual trajectory till the forecast horizon is, therefore, very much useful and desired. So, we propose a modelling structure using the bottom-up approach to cope with these matters and to evaluate the trajectory of long term annual electricity consumption of a sector of the Brazilian industry up to 2050 considering energy efficiency (EE) scenarios. It is important to emphasize that Brazil is a developing country, and to build a bottom-up approach was a challenge, mainly due to the fact that this model is data intensive. In particular, this modelling was applied in the pulp and paper sector. The main goal was to consider technological diffusion scenarios in EE measures, and show the energy savings achieved. The results point an energy savings in the order of 25% when an actual scenario is considered. [ABSTRACT FROM AUTHOR]

In this paper an original and exhaustive mathematical modelling of air impingement drying systems for the production of tissue paper in the Yankee-hoods configurations is reported, which offers the possibility to optimize its energy performance. The model takes into account many detailed operative parameters of the overall drying process with the aim to execute its energy and mass balance and to evaluate its energy performances. The validity of the mathematical model has been assessed by comparison with actual data from an existing tissue paper mill. Finally, the energy performances of two different layouts of the air system have been evaluated and compared. Changing the operative parameters of the drying process, such as air jet temperature and speed and moisture content of the extraction air, it is possible to obtain the same paper production with an energy saving of about 4.5%. In average, the layout with two parallel air circuits assure an energy saving of about 1% with respect to the layout with a single air circuit. [ABSTRACT FROM AUTHOR]

The waste biomass has immense opportunities and plenty of potentials to be an efficient source of renewable energy. Initially, native unripe coconut husk (NCH) was used as raw material for fluidized bed gasification. Then NCH was treated with paper and pulp waste water to impregnate metals present in it for getting enhanced H 2 yield in fuel gas. Humidified air was used as gasifying medium, which served the purpose of introducing water vapour to take part in the gasification process. Then after, gasification medium was retrofitted with CO 2 , which enhanced both the higher heating value (HHV), and CO and H 2 content in the fuel gas. This research serves the dual benefit of energy generation and waste minimization. HHV of unripe coconut husk was investigated and found to be 20.95 MJ/kg. H 2 yield and HHV from impregnated coconut husk (ICH) were obtained as 55.55 vol % and 5.24 MJ/Nm3, respectively at HER 0.1 and gasification temperature of 850 °C in case of fluidized bed gasification. The GC-MS analysis of fuel oil obtained from ICH gasification was done to get the information about high yield of fuel gas as promise product of fluidized bed gasification. • Humidified air fluidized bed gasification of coconut husk with CO 2 was performed. • Paper and pulp wastewater was used for metals impregnation onto coconut husk. • Hydrogen content increased in humidified air gasification of treated coconut husk. • CH 4 in fuel gas decreased for humidified air with CO 2 resulting in decrease of HHV. • GC-MS fuel oil analysis resulted less number of elements showing higher gas yield. [ABSTRACT FROM AUTHOR]

Magazines and newspapers, as two kinds of municipal solid waste, were investigated as the fuel feedstock in a hybrid direct carbon fuel cell. These carbon sources, together with a reference carbon source-activated charcoal, were characterized by such techniques as X-ray diffraction spectra, X-ray photoelectron spectroscopy, and thermal gravimetric analysis, among others. The results indicate that the carbon from magazine waste paper was more abundant in calcite and magnesium calcite, with more oxidation degree of carbon and higher thermal reactivity, compared with the other two carbon sources. Then, the cell performance fed with such carbon sources was tested in a homemade device. The cell fed with magazine waste paper carbon showed the highest performance among the three carbon sources, with a peak power density of 172 mW/cm 2 at 650 °C. The cell performance results indicated that waste paper carbon sources, with a surface containing certain inherent impurities (calcite and magnesium calcite) and a high oxidation degree of carbon, could favor the thermal gasification of carbon fuel, and thus considerably enhance cell performance, especially for the operating temperatures below 700 °C. This study demonstrated that waste paper carbon sources could be promising fuel feedstock for hybrid direct carbon fuel cells. [ABSTRACT FROM AUTHOR]

The Swedish pulp and paper industry (PPI) must increase energy efficiency to remain competitive on the global market, which has experienced entries from countries with cheaper energy and raw material supplies. Interactions among variables for energy use, production, energy management, electricity price and firm characteristics (FC), in different types of mills, i.e., pulp, paper and integrated mills, in Sweden from 2006 to 2015 indicate that correlations among the studied variables were different in different types of mills. This difference between types of mills seemed to originate partly from varying accessibility to production residue that could be used for energy. For all types of mills, variation of electricity prices did not correlate significantly with energy efficiency during the study period. The studied FC were firm's age, number of employees, number of companies in company group, net sales and profit for the year. Energy efficiency was more affected by the variables characterizing energy and production compared to the variables representing FC. This study also suggested presence of possible discrepancies between FC that were perceived as barriers to energy management towards energy efficiency, according to previous studies, and what was shown by the data combining variables representing energy use, production and FC. [ABSTRACT FROM AUTHOR]

The effects of five commercially available hydrolytic enzyme additives on methane yields from dehydrated paper pulp sludge (DPPS) were determined in 5L pilot-scale reactors operated in semi-continuous mode for 60 days. Methane production was 40% and 43% higher in reactors receiving Novozymes and Novalin additives, respectively, compared to controls. Effects of time of DPPS inclusion on bacterial and archaeal microbial communities were many times larger than effects of enzyme type as enzyme addition did not produce rearrangements larger than random fluctuations observed in reactors receiving only DPPS. The ratio between volatile organic acids and alkalinity signified progressive decrease in process stability until day 45 irrespective of enzyme supplementation. Complementation with clarified pig slurry (1.5% vol.) for subsequent 15 days effectively stabilized process parameters and was sufficient for microbial communities to maintain DPPS hydrolytic capacity and process additional carbon flow derived from hydrolytic activity of enzyme additives. Consequently, initially unadapted full-scale biogas plant inoculum was capable of significantly increased methane yields from DPPS. Based on annual DPPS availability in EU the potential for additional energy recovery was estimated to be in the range of nearly 1 TJ. [ABSTRACT FROM AUTHOR]

A kind of wood pulp fiber paper (WPFP) was proposed as candidate for the matrix of desiccant wheel. Silica gel was coated on WPFP by impregnation method and the corresponding coating ratio was obtained and analyzed. Then the thermal conductivity, pore structure and adsorption/desorption performances of WPFP coated with silica gel were tested and analyzed. The results indicated that the WPFP has high coating ratio for silica gel due to its hydrophilic characteristic. The thermal conductivity of WPFP coated with silica gel after the first coating increases obviously compared with raw WPFP and reaches to 0.1292 W/(m⋅K). In addition, the WPFP coated with silica gel after the first coating has high specific surface area and its maximal adsorption quantity for water vapor can be 0.240 g/g. Finally, the DCOP of the desiccant wheel using WPFP as matrix obtained by numerical simulation can be 1.75 under the given working condition that the temperature of regeneration air is set as 90 °C and the inlet condition of process air is set as 34.3 °C and 56.2% RH. It is indicated that the desiccant wheel using WPFP as matrix can meet the requirement of air dehumidification and save energy by 7.35% simultaneously. • Novel desiccant wheel using WPFP with high coating ratio as matrix was proposed. • WPFP belongs to hydrophilic material and has high coating ratio for silica gel. • The water vapor adsorption quantity of WPFP can be fitted well by D-A equation. • The DCOP of the desiccant wheel with WPFP as matrix can be 1.75. [ABSTRACT FROM AUTHOR]

Production of transportation fuels from biorefineries via biomass gasification has been suggested as a way of introducing renewable alternatives in the transportation system with an aim to reduce greenhouse gas emissions to the atmosphere. By co-locating gasification-based processes within heat demanding industries, excess heat from the gasification process can replace fossil or renewable fuels. The objective of this study was to compare the heat integration potential of four different gasification-based biorefinery concepts with a chemical pulp and paper mill. The results showed that the choice of end-product which was either methanol, Fischer-Tropsch crude, synthetic natural gas or electricity, can have significant impact on the heat integration potential with a pulp and paper mill and that the heat saving measures implemented in the mill in connection to integration of a gasification process can increase the biomass resource efficiency by up to 3%-points. Heat saving measures can reduce the necessary biomass input to the biorefinery by 50% if the sizing constraint is to replace the bark boiler with excess heat from the biorefinery. A large integrated gasification process with excess steam utilisation in a condensing turbine was beneficial only if grid electricity is produced at below 30% electrical efficiency. [ABSTRACT FROM AUTHOR]

This paper evaluates the environmental impacts of different alternatives for handling of sludge from paper and pulp mills in Sweden, using Life Cycle Assessment (LCA). The common practice of incineration of biosludge with energy recovery followed by landfilling of ash (System A) was compared with the alternative of digesting sludge anaerobically to produce biogas using different digestate residue management options. The digestate produced from anaerobic digestion (AD) was assumed to be incinerated for heat energy recovery in System B or pyrolyzed for biochar production in System C to be mixed with forest soils. The impact categories considered in this work are climate change, non-renewable energy use, mineral extraction, aquatic ecotoxicity, carcinogens and non-carcinogens. The LCA results demonstrate that the two proposed systems significantly reduce the environmental impacts of biosludge management relative to incineration. An 85% reduction in the aquatic ecotoxicity impact is achieved in System C, due to the reduced mobility of heavy metals in biochar relative to ash. System C, on the whole, outperformed the other two, leading the authors to the recommendation that the use of pulp and paper mill biosludge in biogas-biochar production systems is preferable to merely recovering energy from it. • Anaerobic digestion (AD)-pyrolysis and AD-incineration were modelled as biosludge treatment technologies. • Immobilization of the heavy metals in biochar significantly reduced aquatic ecotoxicity. • The lowest carcinogens and non-carcinogens impacts were offered by the AD-pyrolysis system. • From an environmental point of view, biogas-biochar is preferable to merely energy recovery. [ABSTRACT FROM AUTHOR]

The P&P (pulp and paper) industry in Taiwan is highly energy intensive and there is much product diversification. Taiwan has extremely limited coal and petroleum resources and imports 98% of its energy supply. Increased energy utilization efficiency to reduce energy consumption is necessary for industry in order to implement energy audit recommendations. This work summarizes the energy-saving potential of 118 firms from 2009 to 2013 as determined by on-site energy audits, as well as the energy savings implemented in 2011 by 72 firms in Taiwan's P&P industry, according to data from the on-line Energy Declaration System. It is found that the total of the energy-saving potential and the implemented energy savings are 168.3 and 762.1 TJ, respectively. The results of this study can serve as a reference for current P&P operations and as a base case for stimulating changes in energy utilization. [ABSTRACT FROM AUTHOR]

This study shows a comparative techno-economic analysis of the integration of biomass gasification for generation of producer gas to be used in electricity production and to replace natural gas in the lime kilns of the pulp and paper industry. Three study cases with alternative configurations of the energy system integrating biomass gasification were analysed, including or not the co-generation of electricity and thermal energy, namely: i) Case I, for generation of electricity from residual forest biomass (RFB) in an integrated gasification combined cycle system, ii) Case II, generation of producer gas by RFB gasification for replacement of natural gas in the burners of a lime kiln, and iii) Case III, as an integration of Cases I and II for combined production of electricity and heat. Residual forest biomass from eucalyptus logging activities for feedstock processing for the pulp and paper industry was considered as fuel for direct (air) gasification in bubbling fluidized bed. The analysis made is supported on review reports, namely, the evaluation of the existing literature on investment projects in biomass power plants, and on experimental investigation for determining the composition of the producer gas from gasification of the selected feedstock. An economic model was developed that combines the net present value, internal rate of return and payback period. The main results of the energy system analysis show that the net electricity generation is between 72 and 83 GWh/year, while the production of CaO in the lime kiln supported by combustion of producer gas, is 82.12 kt/year, and a global energy efficiency between 21.70 and 34.17 % is achieved for the analysed configurations of the energy system. The results of the economic analysis show a positive NPV, an IRR greater than the discount rate and a PBP less than the useful life of the plant. The sensitivity analysis shows quite favorable investment projections given the low probability that the NPV will reach negative values and compromise the economic viability of the project. • The technical-economic viability of the forest biomass residues gasification is addressed. • Integration of IGCC concepts in the pulp and paper industry is reviewed. • The opportunities and drawbacks of IGCC in the pulp and paper industry are discussed. • Replacement of natural gas for producer gas for electricity generation and lime production is analysed. • A Monte Carlo sensitivity analysis is performed. [ABSTRACT FROM AUTHOR]

Urgent need for waste disposal and renewable energy have opened up promising pathways for renewable and sustainable fuel production to substitute traditional fossil fuels. In this study, catalytic co-pyrolysis of waste paper (WP) and polyvinyl chloride (PVC) as typical municipal solid wastes was experimentally investigated towards hydrogen-rich syngas production. Results indicated the maximum H 2 yield (429 μmol·g cat −1·min−1) was obtained with 60% PVC weight ratio under 900 °C which was higher than single component pyrolysis. Higher hydrogen yield (681.76 μmol·g cat −1·min−1) appeared over Fe/CeO 2 –CaO under the optimal conditions compared to that of Ru/ZSM-5-CaO (445.54 μmol·g cat −1·min−1). From the calculated non-isothermal kinetic parameters, both catalysts could reduce activation energies. Proper porous structure and CaO content in the catalyst could enhance hydrogen production via carbon species fixation. • Catalytic co-pyrolysis of waste paper and PVC blends for hydrogen production is firstly investigated. • Enhanced interactions of PVC/waste paper during pyrolysis was found for H 2 production. • Non-isothermal kinetics were implemented to evaluate catalytic co-pyrolysis. • High H 2 yield was obtained over Fe/CeO 2 –CaO for its pore structure and sorption enhancing effect. [ABSTRACT FROM AUTHOR]

This article presents results of a pulsed UV laser method for the simultaneous reduction of graphite oxide (GO) and patterning of reduced graphene oxide (rGO). This direct laser writing method was applied to the fabrication of graphene-based, in-plane interdigitated micro-supercapacitors (μ-SCs), prepared on free-standing GO paper (10 μm thick). The electrochemical performance of μ-SCs was studied using two different electrolytes (KOH and NaCl). The results from cyclic voltammetry measurements exhibited typical electrical double layer behavior, with specific capacitances of 9.3 μF/cm2 and 13.8 μF/cm2 (at a scan rate of 10 mV/s) for KOH and NaCl electrolytes, respectively. The μ-SCs exhibited good performance, with retention of 95% of the original capacitance values after 3400 charge-discharge cycles. When compared to devices obtained by conventional lithographic techniques, the laser fabrication of planar μ-SCs is faster, cost-effective and scalable. We believe this one-step and environmentally friendly laser-assisted method to be a good alternative for the fabrication of flexible energy storage devices. • Direct laser writing is used to design the interdigitated electrode for μ-supercapacitor. • Direct laser writing on GO paper is simple, chemical free and room temperature technique. • The laser parameters are optimized to complete photothermal reduction of GO paper. • GO paper-based μ-supercapacitors reveal excellent electrochemical performance. [ABSTRACT FROM AUTHOR]

Thin, lightweight, stackable, solid-state supercapacitors are in great demand in the electronics industry because of their use in miniaturized devices. Herein, we report a simple and novel strategy to fabricate ultra-thin, lightweight, and stackable symmetric supercapacitors using MnO 2 -incorporated carbon nanotube (CNT)-web paper. SEM and TEM analyses revealed a uniform nanometer-scale coating of MnO 2 on the individual fibers of the CNT-web paper after simple deposition at room temperature. The network structure of free-standing conductive CNT-web paper provides a short diffusion path, allowing for complete utilization of MnO 2 in the charge storage process. A MnO 2 /CNT-web paper electrode showed an excellent areal capacitance of 135 mF cm −2 at 5 mV s −1 with a remarkable capacitance retention of 95% after 10,000 cycles. A symmetric solid-state supercapacitor containing MnO 2 /CNT-web paper displayed a high areal capacitance of 57 mF cm −2 with an energy density of 0.018 mWh cm −2 and a capacitance retention as high as 86% after 10,000 cycles. In addition, the voltage and capacitance were tripled by simply stacking three symmetric supercapacitors and connecting them in series and in parallel, respectively. We are optimistic that the excellent performance of the ultra-thin CNT-web paper-based supercapacitors demonstrated here will facilitate the development of compact supercapacitor banks in the near future. [ABSTRACT FROM AUTHOR]

The preparation and application of heteroatom doped carbons have attracted lots of attention in the past years. In the current work, a facile synthesis of nitrogen doped carbon with filter paper as the carbon source and urea as the nitrogen source was presented. Filter paper was first impregnated with urea solution, and was then carbonized and activated. The carbons' physical and chemical properties were studied. For the application in CO 2 adsorption, impacts from porous characteristics and nitrogen doping were discussed and differentiated. The results suggested that nitrogen doping was beneficial to the improvement of CO 2 uptake, but suitable porous properties were the most important factors. Nitrogen doping showed more significant effects on enhancing the adsorption heat and selectivity. The research of carbonaceous CO 2 adsorbent should focus on nitrogen doped carbons with high porosity. • Urea loaded filter paper is used as starting material for nitrogen doped carbon. • Effects of nitrogen doping and porous structure on CO 2 adsorption are studied. • CO 2 uptake at 273 K and 1 bar reaches 5.12 mmol/g. • Nitrogen doping has obvious effects on CO 2 adsorption heat and selectivity. [ABSTRACT FROM AUTHOR]

A new process for the production of bioethanol from paper mill sludge (PMS) is described in this work. PMS biomass feedstock was processed via the simultaneous saccharification and fermentation (SSF) with and without accelerants. The enzymatic hydrolysis and fermentation were first evaluated, and the energy demand was 2.2 MJ/L of produced ethanol. When the enzymatic hydrolysis and fermentation were combined, the energy demand was reduced to 1.0 MJ/L ethanol, the sugars production increased, and the overall capital cost of the process decreased. The sugar yield was improved by adding accelerant and selecting the optimal fiber recovery method. The accelerant improved the enzymatic hydrolysis via a pathing/bridging mechanism. The SSF with the chemical fiber recovery method coupled with accelerant addition would be the best process configuration. Upon this combination, the glucose profile was enhanced from 9.8 g/L to 17.0 g/L. The sludge fiber conversion by SSF was improved by selecting an efficient fiber recovery method combined with the accelerant addition. SSF in chemical fiber recovery with accelerant addition was the best process by a 10% improvement of ethanol yield. The proposed process configuration offers a lower cost and sustainable process and contributes to the circular economy of zero waste discharges. • A combined SSF process using PMS feedstock to produce bioethanol was developed. • The energy saving in an integrated process was 1.2 MJ/L ethanol. • The optimal fiber recovery from paper mill sludge was achieved via acid treatment. • The optimal fiber recovery increased fractional glucose by 27%. • The cationic accelerant improved the enzymatic hydrolysis by 10% due to the patching mechanism. [ABSTRACT FROM AUTHOR]

In this study, the methane production potential of paper industry waste sludge (PPWS) was investigated using consortium of hydrolytic enzymes (CHE) mediated poly3hydroxybutyrate (P3HB) method. Initially, P3HB was extracted from municipal aerated waste sludge (MARWS) by optimizing extraction time and dimethyl carbonate dosage. Maximum of P3HB (910 mg/g) was extracted at 60 min of extraction time and 4 mL of dimethyl carbonate dosage. Then, the influence of extracted P3HB dosage (5–120 mg) on methane production from PPWS was examined. 75 mg of P3HB dosage was exhibited higher methane production (153 mL/g VS) when compared to other P3HB dosage. Further, CHE mediated pretreatment was performed by varying CHE dosage and temperature. At optimized CHE dosage (2.5 mL) and temperature (45 °C), maximum of chemical oxygen demand (COD) liquefaction, suspended solids reduction (SSR) and lignin removal were found respectively to be 23.7%, 18% and 61% which was higher than control (COD liquefaction (0.9%), SSR (0.5%) and lignin removal (0.7%)). Also, biomethane potential assay was carried out in which CHE mediated P3HB method attained higher methane production (280 mL/g VS) when compared to CHE method (217 mL/g VS) and control (47 mL/g VS). • Biopolyester was extracted by varying extraction time and dimethyl carbonate dose. • The extracted biopolyester was identified as P3HB. • P3HB dose had a significant impact on methane production from PPWS. • Maximum of COD liquefaction and SSR were noticed in CHE pretreatment study. • Higher methane production was attained by CHE mediated P3HB method. [ABSTRACT FROM AUTHOR]

This paper presents a comparison between four gasification-based biorefineries integrated with a pulp and paper mill. It is a continuation of 'Transportation fuel production from gasified biomass integrated with a pulp and paper mill - Part A: Heat integration and system performance'. Synthesis into methanol, Fischer-Tropsch crude or synthetic natural gas, or electricity generation in a gas turbine combined cycle, were evaluated. The concepts were assessed in terms of GHG (greenhouse gas) emissions and economic performance. Net annual profits were positive for all biofuel cases for an annuity factor of 0.1 in the year 2030; however, the results are sensitive to biofuel selling prices and CO 2,eq charge. Additionally, GHG emissions from grid electricity are highly influential on the results since all biofuel processes require external power. Credits for stored CO 2 might be necessary for processes to be competitive, i.e. storage of separated CO 2 from the syngas conditioning has an important role to play. Without CO 2 storage, the gas turbine case is better than, or equal to, biofuels regarding GHG emissions. Efficiency measures at the host mill prior to heat integration of a gasification process are beneficial from the perspective of GHG emissions, while having a negative impact on the economy. [ABSTRACT FROM AUTHOR]

Abstract The paper drying process has the highest level of energy consumption in the pulp and paper production process. Analysis and optimization of the energy system during the paper drying process is critical for improving the energy efficiency of the entire paper mill. In the existing model for the paper drying process, the solution requires accurate boundary conditions such as the air temperature and humidity of the pocket area and the cylinder surface temperature, which are very difficult to obtain in the papermaking process. This can result in significant deviations between the model solution and the actual production process. This paper focuses on the single-tier dryer cylinder-based paper drying process that has been widely used with high-speed papermaking machines in recent years. A mathematical model is proposed based on real-time data. The verification via industrial production demonstrates that the proposed model is reliable for the paper drying process. Based on the simulation results, two optimization operations have been proposed. The energy consumption decreases from 1.51 t steam/t paper to 1.44 t steam/t paper, 4.6% of the steam and 1.26 × 106 RMB can be saved for a medium-scale paper mill with the annual production capacity of 105 t paper. Highlights • Mathematical model for the single-tier cylinder based paper drying process is proposed. • Both the steam-condensate system and the paper drying process are considered. • The simulation results are verified by the industrial data from a papermaking enterprise. [ABSTRACT FROM AUTHOR]

A facile strategy is designed for the fabrication of flexible and free-standing ternary CoSnO 3 /graphene/carbon nanotubes (CoSnO 3 /GN/CNTs) composite papers through a simple filtration, followed by annealing process. The CoSnO 3 /GN/CNTs composite papers with high flexibility and tailorability can be easily fabricated. The CoSn(OH) 6 nanoparticles/graphene oxide/carbon nanotubes (CoSn(OH) 6 /GO/CNTs) composite papers obtained by a simple filtration method are transformed into CoSnO 3 /GN/CNTs composite papers after a thermal treatment process. In this unique composite structure, CoSnO 3 nanoparticles (nanocubes and nanoboxes) are embedded homogenously into the 3D framework of graphene and carbon nanotubes, respectively, in which offers not only a 3D conductive network and a dual restriction on the aggregation of CoSnO 3 nanoparticles, but also accommodates the large volume expansion of CoSnO 3 nanoparticles. When used directly as binder- and conductive agent-free anodes for lithium-ion batteries, the CoSnO 3 /GN/CNTs composite papers exhibit superb electrochemical properties including extraordinary reversible capacities, superior rate capabilities and stable cycle performances compared to CoSnO 3 nanoparticles and GN/CNTs paper, suggesting a new pathway for the rational engineering of anode materials. [ABSTRACT FROM AUTHOR]

In order to explore hydrothermal carbonization (HTC) behavior of municipal solid wastes (MSW), four typical components, waste textile, wood, paper and food, were employed to perform HTC and co-HTC process. The experiments were conducted at 240 ○C and 90 min with a 1:12 solid/liquid ratio, where blending ratios of 1:3, 1:1 and 3:1 with waste textile were investigated. As expected, the increase of fixed carbon and carbon content improved the fuel potential of hydrochar. The synergistic index (SI) analysis clearly indicated that significant synergistic effects occurred during co-HTC process. Specifically, all the SI values of hydrochar yield from co-HTC of waste textile with wood and paper were negative, while all SI values of hydrochar yield for waste textile with food were positive. Particularly, the SI values of fuel ratio for all hydrochars were positive which suggested co-HTC could promote to enhance the coalification degree of hydrochars. However, the undesirable increment of O content for hydrochars (derived from 75%waste textile-25% waste food and 50%waste textile-50% waste food) decreased the high heating value. The combustion behavior and nth-order kinetic model analysis showed that hydrochars derived from co-HTC rendered a more stable and lasting combustion profile. Image 1 • The synergistic index indicated that significant synergistic effects occurred during co-HTC. • The SI values of hydrochar yield from co-HTC of WT with WW and WP were negative. • The SI values of fuel ratio for all hydrochars were positive suggesting enhanced coalification degree. • Hydrochars derived from co-HTC rendered a more stable and lasting combustion profile. [ABSTRACT FROM AUTHOR]

Paper mill sludge (PMS) can be efficiently utilized to produce fuels and chemicals. However, wastewater is usually generated during the de-ashing step of the PMS for fibrous materials recovery. Per process requirements, the wastewater stream must be treated which results in an increase in the overall process production cost. Therefore, this research aims at reusing the wastewater produced during the de-ashing step as a substitute for freshwater addition during the conversion of PMS into ethanol. The advantages of this approach include reducing the amount of wastewater produced and enhancing the overall efficiency of the process. It will contribute to the circular economy of zero waste discharges. The results showed that 30% of the process wastewater can be recycled without affecting the enzymatic hydrolysis and ethanol fermentation. Hence, the amount of wastewater that needs to be treated is reduced by 30% resulting in a cost reduction of 22.5%. The results also showed that wastewater recycling minimized the energy demands in the distillation and evaporation units by 1206 kJ/kg. The energy reduction is due to the increase of metals and total soluble solids in the broth stream after fermentation. This process configuration enhanced the process economy, saved energy and managed waste streams. • Reuse of wastewater in the paper mill sludge conversion. • A certain degree of recycling has no impact on the glucose yield. • Wastewater recycling reduced the energy demand of the process by 1251 kJ/kg metric tons wastewater. • Cost-saving of wastewater treatment by 22.5% when a 30% recycling degree achieved. [ABSTRACT FROM AUTHOR]

A highly flexible and free-standing, porous Mn 3 O 4 nanorod/reduced graphene oxide (pMn 3 O 4 NR/rGO) paper was prepared by a two-step process: vacuum filtration and thermal treatment. The MnOOH nanorod/graphene oxide (MnOOH NR/GO) paper obtained by a simple filtration method is transformed into pMn 3 O 4 NR/rGO paper after a thermal reduction process. A unique lamellar structure was achieved with pMn 3 O 4 NR homogeneously intercalated within the GO layers. In the hybrid structure, graphene nanosheets provide a conductive pathway and act as the buffer layers to prevent the pulverization of pMn 3 O 4 NRs during reaction. Therefore, when used as the anode in lithium ion batteries, this pMn 3 O 4 NR/rGO paper exhibits a first high discharge capacity of 943 mA h g −1 , which quickly stabilizes and remains at 573 mA h g −1 even after 100 cycles at 100 mA h g −1 , which is much higher than the discharge capacity of the corresponding pristine graphene paper (183 mA h g −1 ). [ABSTRACT FROM AUTHOR]

In this work, an analysis of co-pyrolysis municipal solid waste and paper sludge with additive (MgO) were investigated by TG-FTIR and Py-GC/MS. The proportions of paper sludge in the blends were 10%, 30% and 50%, respectively. The pyrolysis characteristics, the yields of pollutants (CO, SO 2 , NO, HCl) and CO 2 , the products and chemical composition, the kinetic behaviors and the distribution activation energy model were investigated. After adding paper sludge, the sums of pollutants reduced, the amount of aliphatic hydrocarbons decreased and oxygenates compounds increased. After adding MgO, the results showed that the residue mass decreased, the emission of pollutants reduced, the ratio of aliphatic hydrocarbons became larger, the ratio of oxygenates compounds became smaller, and the activation energy reduced. According to the beforementioned results, the 30% percentage of paper sludge in the mixture with MgO might be the most suitable ratio for co-pyrolysis. [ABSTRACT FROM AUTHOR]

Coconut husk was treated with pulp and paper industry wastewater for impregnating metal constituents present in it. The present work was focused on humidified air as an alternative to steam for generation of hydrogen-rich fuel gas in an updraft fixed-bed gasification column. A series of experiments were performed to see the effect of temperature, air/humidified air and CO 2 addition on gas yield and composition. Furthermore, some experiments were also conducted by varying impregnation temperature at the optimum condition to see the effect of impregnation temperature on gas yield and calorific value. The gross calorific value (GCV) of coconut husk C 53.84 H 77.80 O 43.99 N was estimated as 23.21 MJ/kg. The fuel gas production was found in the range from 0.68 to 2.89 Nm 3 /kg for native and from 0.83 to 3.13 Nm 3 /kg for impregnated coconut husk. The GCV of fuel gas yield was found to be maximum of 12578 kJ/Nm 3 for impregnated coconut husk at impregnation temperature of 105 °C, retrofitted with CO 2 in humidified air. The concentration of hydrogen was found maximum for impregnated coconut husk. The present gasification process not only provides feasibility of green energy but also renders to reduce the pressure of the environmental pollution created by the unutilized coconut husk. [ABSTRACT FROM AUTHOR]

Accurate understanding of the marginal energy-saving costs of energy-using entities is critical for regulatory authorities to formulate and implement energy-saving policies. This article brings out an easy-to-operate analytical framework to measure the marginal energy-saving cost and construct energy conservation supply curve with the help of data envelopment analysis and quantitative model. Furthermore, taking China's pulp and paper industry as an example, the authors discuss the difference of economic costs between industry energy-saving task assignment with and without considering the difference of marginal energy-saving costs of different energy using entities with the help of linear programming model. The main empirical results are as follow. First, there is a big difference in the industrial marginal energy-saving costs in different provinces. The difference between the highest and lowest energy-saving costs is twice as large. Second, the optimal energy-saving task assignment based on an accurate energy conservation supply curve can help to save nearly 35% of total economic cost. • An alternative method of measuring energy conservation cost is provided. • An optimal energy saving task assignment model is constructed. • The problem of trade-off between efficiency and equity in policy making is discussed. [ABSTRACT FROM AUTHOR]

In this study, through orthogonal experiments design, the influences of ultrasonic pretreatment (frequency, power and treatment time) on co-pyrolysis and catalytic pyrolysis of municipal solid waste and paper mill sludge were explored. The differential thermogravimetry curves became steeper and the peak values were larger after pretreatment, which made the pyrolysis reaction rapidly and the volatile separated out timely. However, the change of pyrolysis characteristics was not obvious after adding MgO. The catalytic effect of MgO increased with the increase of sludge ratio. After pretreatment, the average activation energy of the samples had an overall increasing trend, but the change was small. MgO had a decreasing effect on activation energy, and with the increasing proportion of sludge the degree of reduction became significant. In addition, high ultrasonic frequency had a negative effect on reducing activation energy. • Study on the co-pyrolysis of municipal solid waste and paper mill sludge. • The differential thermogravimetry curves became steeper after pretreatment. • Distributed activation energy model was used to calculate the kinetic parameters. • The average activation energy had a minor increasing trend after pretreatment. • High ultrasonic frequency had a negative effect on reducing activation energy. [ABSTRACT FROM AUTHOR]

Among the various waste-to-energy conversion methods, gasification is a technically feasible option for municipal solid waste valorization, meeting current emission limits and reducing landfill disposal burden. This work investigates the potential of paper rich (⁓ 76 % wt.) commercial refuse-derived fuel (RDF) having high ash content (⁓ 17 % wt.) for gasification and co-gasification in downdraft gasifier. The ash formed from RDF, with higher proportion of alkaline earth metals (Ca and Mg) and lower proportion of alkali metals (Na and K), can effectively avoid agglomeration and clinker formation during gasification. The producer gas obtained from RDF gasification reports a maximum lower heating value of 4.34 MJ/Nm3at an equivalence ratio of 0.34 with corresponding cold gas efficiency of 59.24%.Co-gasification of RDF with biomass was examined as a strategy to reduce overall ash content of the mixture, using sawdust. Co-gasification has exhibited a synergy between RDF and sawdust when the RDF fraction in feedstock is at the higher side. A maximum lower heating value of 4.65 MJ/Nm3 was obtained during the co-gasification and the tar yield reduced from 13.6 g/Nm3to 8.8 g/Nm3 when RDF in the feed increased from 25% to 75% (w/w). • Investigates potential of paper-rich RDF for gasification and co-gasification. • Absence of agglomeration and clinker formation during gasification and co-gasification. • Producer gas with LHV and CGE of 4.34 MJ/Nm3 and 59.24%, respectively from RDF gasification. • RDF has exhibited synergy with biomass at higher RDF fraction during co-gasification. • Reduction in tar content with increase in RDF fraction during co-gasification. [ABSTRACT FROM AUTHOR]

This work reports an innovative simulation method for effectively utilizing paper-mill sludge based on the co-gasification approach for energy-enriched renewable fuel production. An Aspen plus-based co-gasification model was developed to simulate and examine the synergetic effects of biomass and paper-mill sludge co-gasification. Initially, the model was validated using experimental data from the reported literature and found good agreement regarding gasification and co-gasification approaches. Sensitivity analysis of biomass gasification revealed that the maximum H 2 content of 29.6% and CO (36.0%), LHV (7.8 MJ/Nm3), 72.2% (CCE) was obtained at optimal (850 °C: temperature; 1 bar: pressure; 0.2: ER) conditions. Further, the H 2 proportion enhanced, and CO declined to 38.8 and 30.7% at the same operating conditions, respectively, with a co-gasification ratio of 50% compared to 0% (H 2 : 29.6% and CO: 36.0%). However, with increasing the co-gasification ratio beyond 20%, the CO content started to follow upward trends; at the same CGR, the H 2 , LHV, and CCE observed were 36.0%, 7.76 MJ/Nm3, and 65.2%, respectively. Hence, the developed co-gasification model can provide vital information for large-scale gasifier design, operating decisions, and optimization using different biomass blends. • Biomass and PMS utilization to produce renewable fuel. • Co-gasification parametric effects evaluation on product yield. • Increasing the proportion of PMS in feedstock mixture increases H 2 content. • 20% PMS co-gasification provided consistency with reported literature. [ABSTRACT FROM AUTHOR]

The generated gas bubbles in microfluidic fuel cells (MFCs) cover the active surface area of the electrode and greatly limit the cell performance. In this study, a feasible approach is proposed to effectively accelerate bubbles removal and enhance cell performance by embedding a paper separator in the middle of the microchannel. Visualization of bubble behaviors and the corresponding electrochemical measurements are performed to investigate the effect of bubbles on the cell performance. Periodical process of the bubble growth and removal leads to the fluctuation in the current density of the MFC. The rapid gas removal and the low ohmic resistance are observed after embedding a layer of filter paper in the microchannel, causing improved fuel transfer and smaller ohmic loss. Although the current density fluctuates more frequently, the fluctuation amplitude decreases and the cell performance is enhanced. Compared with the MFC without paper separator, the maximum power density and the limiting current density of the MFC with paper separator is increased by 25.2% and 130%, respectively. Moreover, the cell performance is improved with increasing the flow rate of reactant solution and the peak power density achieves 25.9 mW cm−2 under flow rate of 1500 μL min−1. • A microfluidic fuel cell with paper separator is proposed to enhance gas removal. • Bubble behaviors as well as its effect on the performance are studied. • The paper separator can restrict bubble size and improve cell performance. • Effect of flow rate on the bubble behavior and cell performance is studied. • Embedding a paper separator is a good and effective way for gas management. [ABSTRACT FROM AUTHOR]

Power generation by variable renewable energy (VRE) is expected to expand for decarbonization, although it is difficult to ensure stabilization of the energy demand due to fluctuations in the power output from VRE. To accelerate VRE implementation, wind-powered thermal energy systems (WT th -ES), which can provide dispatchable power using wind–thermal energy converter (WEC th) and thermal energy storage (TES), have been proposed. In this study, we are tackling the installation of VRE, i.e., wind energy, by TES with WEC th compared with wind turbine (WT p) in paper mills to demonstrate the applicability of TES in an industrial sector. Conventional and alternative energy systems in paper mills with TES were mathematically modeled and simulated to analyze the transmittable power output and the greenhouse gas (GHG) emissions by life cycle assessment. With the installation of TES and wind energy, transmittable power could be increased with GHG emissions reduction. However, their excess installation or unbalanced combination resulted in an increase in GHG emissions and a decrease in transmittable power. By comparing the cases, the combination of paper mill, TES, and WEC th could convert thermal energy efficiently and mitigate fossil fuel consumption for multiple production of paper and power from the paper mill. • A wind-thermal energy converter (WEC th) and a wind turbine (WT p) were compared. • Energy flows and GHG emissions of paper mills with TES and wind were simulated. • Paper mills reduced GHG of power generation less than fossil fuel-fired power plants. • Excess TES reduces dispatchable power generation and increases GHG emissions. • Paper mills with WEC th s and TES have the potential to be regional energy suppliers. [ABSTRACT FROM AUTHOR]

This work reports the charge storage ability of Ni x Co 1-x (OH) 2 nanosheet-carbon nanofoam paper (CNFP) composites prepared by electrodeposition for high areal capacity supercapacitor electrodes. The Ni x Co 1-x (OH) 2 film grew through instantaneous nucleation, uniformly covered CNFP, and displayed a porous morphology composed of a nanosheet percolation network. The electrochemical response of the Ni x Co 1-x (OH) 2 films was tuned by varying the Co to Ni ratios. The optimized Ni x Co 1-x (OH) 2 stoichiometry resulted in Ni 0.33 Co 0.67 (OH) 2 -CNFP electrodes displaying areal capacity/capacitance values of 1.52 C cm −2 /2.03 F cm −2 at 2.1 mA cm −2 , resulting from the contribution of the double layer capacity of CNFP with the redox capacity of Ni x Co 1-x (OH) 2 . A two electrode cell composed of CNFP as negative electrode and Ni x Co 1-x (OH) 2 -CNFP as positive electrode presented a high areal capacity value of 0.73 C cm −2 at 7.2 mA cm −2 . [ABSTRACT FROM AUTHOR]

Daytime subambient radiative cooling is a most promising alternative to electricity-free building cooling. However, optical performance degradation arising from surface contamination and inevitable parasitic heat gain still pose unprecedented challenges to cool building at subambient temperatures. This paper proposed a superhydrophobic cellulose aerogel cooler (SHB-CAC) as building envelope by integrating self-cleaning capacity, passive daytime radiative cooling and thermal insulation to reduce environmental heat gain. The SHB-CAC demonstrates high solar reflectance (93%) and long-wave infrared emittance (91%), accomplishing a temperature drop of 8.5 °C lower than the ambient under sunlight of 800 W/m2 in the outdoor experiment. Notably, the SHB-CAC possesses low thermal conductivity (28 mW/(m∙K)) that suppresses parasitic heat gain from warmer surrounding and reduces cooling energy consumption. The self-cleaning property resulting from superhydrophobicity protects SHB-CAC from water wetting and dust contamination but also maintains its good surface radiation capacities under different humidity environment. A building energy simulation was conducted and results showed that 43.4% of cooling energy on average could be saved compared to the building baseline consumption, if SHB-CAC was widely used in China, indicating that the strategy of optical and thermal conductivity management of cooler has the potential to reduce the energy consumption of buildings. [Display omitted] • Waste paper is converted into aerogel cooler for building cooling. • High R solar and ε IR , thermal insulation, and self-clean are achieved in one design. • The aerogel achieves a high sub-ambient temperature drop of ∼8.5 °C on daytime. • The aerogel shows that 43.4% of cooling energy could be saved. [ABSTRACT FROM AUTHOR]

The economic feasibility of producing ammonia through the gasification of three different feedstocks produced in pulp and paper mills is investigated in this paper. The first case uses black liquor, the main by-product of the kraft pulping process, as the feedstock, and in the other two cases pulp sludge (PS) and waste sludge (WS) are co-gasified with black liquor. For all three cases, a process model in which mass and energy balances were calculated was developed. The model results were used to estimate the equipment size and estimate costs. Techno-economic models were developed and ammonia production costs were calculated. A case study for Alberta, a western Canadian province, was conducted. The results indicated that for a 10% discount rate (or internal rate of return [IRR]), ammonia production in all three cases is cost competitive with current ammonia prices. The cost of production (COP) of ammonia for all three cases ranges from 743 to 748 $/t. Sensitivity and uncertainty analyses were conducted on the estimated COP, and the results show that the COP is the most sensitive to the capital cost, discount rate, electricity price and plant lifetime. [ABSTRACT FROM AUTHOR]

A novel MEA (membrane electrode assembly) structure of passive μ-DMFC (micro-direct methanol fuel cell) controls water management and decreases methanol crossover. The CNT (carbon nanotube) paper replacing CP (carbon paper) as GDL (gas diffusion paper) enhances water back diffusion which passively prevents flooding in the cathode and promotes low methanol crossover. Moreover, the unique structure of CNT paper can also enhance efficiency of oxygen mass transport and catalyst utilization. The passive μ-DMFC with CNT-MEA exhibits significantly higher performance than passive μ-DMFC with CP-MEA and can operate in high methanol concentration, showing the peak power density of 23.2 mW cm −2 . The energy efficiency and fuel utilization efficiency are obviously improved from 11.54% to 22.7% and 36.61%–49.34%, respectively, and the water transport coefficient is 0.47 which is lower than previously reported passive μ-DMFC with CP. [ABSTRACT FROM AUTHOR]

Catalytic co-pyrolysis of biomass and plastics (HDPE (high density polyethylene), PP (polypropylene) and PET (polyethylene terephthalate)) has been performed in a fixed-bed reactor in presence of cobalt based alumina, ceria and ceria-alumina catalysts to analyze the product distribution and selectivity. Catalysts are synthesized using co-precipitation method and characterized by BET (Brunauer–Emmett–Teller) surface area and XRD analysis. The effect of catalytic co-pyrolysis at different temperature with product distribution has been evaluated. The results have clearly shown the synergistic effect between biomass and plastics, the liquid products gradually increases forming with rise in the plastic content in the blend. Gaseous products have yielded most during pyrolysis of blend having biomass/plastics ratio of 5:1 with the presence of 40% Co/30% CeO 2 /30% Al 2 O 3 catalyst with hydrogen gas production touched its peak of 47 vol%. Catalytic performance enhanced with increase with the cobalt loading, with best performance attributing to 40% Co/30% CeO 2 /30% Al 2 O 3 catalyst. [ABSTRACT FROM AUTHOR]

Microfluidic electrolyzers have been fabricated using graphite coated paper electrodes to electrolyze sea water into oxygen (O 2) and hydrogen (H 2) when integrated with a photovoltaic (PV) cell. The 'open' electrolyzer (OME) consists of a microchannel confined by a pair of graphite electrodes, which is drawn with the help of pencil tips. A sea water microdroplet has been dispensed at the junction of the electrodes while the PV cell is integrated to the electrodes to supply current. The microscale width of channel generates a high intensity electric field even at a lower potential, which facilitates the microdroplets to electrolyze into H 2 and O 2 near the cathode and anode. The rate of production of the gases increased with field intensity. In the 'close' electrolyzer (CME), the paper decorated with graphite electrodes is covered with a substrate embedded with polymeric microchannels. The microcapillaries are placed closer to the anode and cathode for in situ separation of H 2 and O 2. The economic, flexible, and metal-free micro-electrolyzer facilitates the water-splitting at a much lower applied voltage at an efficiency of 1–2%. Use of multiple separation channels in CME for production and separation of H 2 and O 2 shows the potential for micro-very-large-scale-integration (μ-VLSI). Paper based microfluidic reactor for production and separation of H 2 an O 2 gases. [Display omitted] • Development of a paper-based electrodes coated with graphite or RGO. • Electrolysis of sea water on the paper based microelectrolyzer. • Development of paper microelectrolyzer integrated with graphite/RGO electrode for electrolysis. • Integration of the solar panel to generate high intensity electric field for water splitting. • Synthesis and separation of hydrogen and oxygen in the OME and CME. [ABSTRACT FROM AUTHOR]

In hot and dry climatic zones, direct evaporative cooling (DEC) system is used as an economical and efficient alternative to traditional air conditioning systems. The present paper concerns comprehensive experimental investigations and analysis of heat and mass transfer characteristics and thermal performance parameters of a bee-hive construction of corrugated-cellulose papers as a new cooling pad material. The performance parameters used to evaluate the effectiveness of the cooling pad materials are the outlet air temperature and relative humidity, pressure drop, humidifier effectiveness, rate of the evaporated water, sensible cooling capacity, specific cooling capacity (SCC), coefficient of performance (COP), specific water consumption (SWC), and Nusselt and Sherwood numbers. The cooling pad performance was investigated for a wide range of air and water temperatures and flow rates and pad thicknesses. The results show the enhancements of heat and mass transfer coefficients and the performance parameters with rising air temperature and water flow rate to humidifier. High values of the performance parameters (h c = 45 W/m2oC and h m = 0.23 m/s, ε h u m = 0.85 and COP = 170) are obtained compared to the traditional pad materials. Experimental correlations for the evaporative cooler performance parameters in terms of air and water temperatures and flow rates pad thicknesses are presented. • Cellulose paper, bee-hive structure has efficient thermal to be used as evaporator cooling pads. • Good thermal-hydraulic characteristics at a wide range of operating and design conditions are obtained. • Presented empirical correlations predict the performance parameters very well. • High values of the performance parameters of the proposed cooling pad were obtained. • The highest saturation efficiency is 84% with associated temperature and pressure drops 18 °C and 8 Pa. [ABSTRACT FROM AUTHOR]

With the continuous increase in underground engineering depth, the risk of coal–rock dynamic disasters, such as rockburst, is becoming increasingly serious and complex threatening the safety of coal resources. To study the effect of horizontal stress on fractal characteristics of rockburst fragments in coal mining, this paper uses a digital drilling instrument to perform rockburst proneness tests on andesite and granite specimens with different horizontal stresses. Fractal theory is used to calculate the fractal dimension of the rockburst fragments for several combinations of parameters. The residual elastic energy index is combined with the fractal dimension of rockburst fragments to assess the propensity of rockbursts from macroscopic and microscopic perspectives. The experimental results show that the positive correlation between the fractal dimension and the A EF obtained under the two methods. The fractal dimensions of andesite and granite are 1.507–1.80 and 1.734–1.979, respectively. According to the rockburst proneness criterion, it is predicted that andesite and granite are all strong rockbursts under confining pressures of 20 MPa, 30 MPa and 50 MPa. Therefore, it is of some theoretical relevance to investigate the rockburst mechanism in terms of both the A EF and fractal dimensions of fragments under different unloading conditions. • Rockburst proneness is studied for rocks using digital drilling instrument with different horizontal stresses. • The residual elastic energy index is obtained from the drilling parameters to estimate rockburst proneness. • The residual elastic energy index is combined with the fractal dimension to assess the rockburst proneness. • The fractal dimensions of andesite and granite are 1.507–1.80 and 1.734–1.979, respectively. • The andesite and granite are all strong rockbursts under confining pressures of 20 MPa, 30 MPa and 50 MPa. [ABSTRACT FROM AUTHOR]

The current study analyzes the potential of an environmentally benign integration of a parabolic trough solar collector (PTSC) with a heat-intensive multi-effect evaporator (MEE) used in pulp and paper industry. Actual plant data was used to simulate the MEE and estimate the steam economy (SE) and steam consumption (SC), which are used to judge the performance of PTSC-MEE system. Four distinct alternatives for the integration are investigated with Self-adaptive Differential Evolution (SaDE) utilized for optimization. Initially, a normal PTSC with four different model configurations of MEE, basic or with energy reduction schemes (ERSs) are tested and found that SE is slightly increased for each. Next, a geometrically optimized/combinatorial optimized PTSC with basic MEE is examined, a rise of ∼3.4% in SE is noted for both, with current integration outperforming one out of three ERSs. Subsequently, geometrical plus combinatorial optimized PTSC with basic MEE is inspected, increase in SE reached 7.59% and two of the three ERSs outperformed. Economic analysis is conducted to estimate the steam saving with different PTSC-MEE systems and corresponding payback periods. The possibility of decarbonization with the various integration possibilities is also explored by evaluating the fuel savings and related CO 2 savings. • Integration of PTSC with an MEE used in pulp and paper industry is investigated. • The fusion of PTSC with MEE is studied with various possibilities. • Self-adaptive Differential Evolution (SaDE) is used for various optimizations. • The steam savings and payback times are estimated for various PTSC-MEE systems. • Decarbonization is studied by analyzing fuel savings and CO 2 reductions. [ABSTRACT FROM AUTHOR]

Abstract We herein report a simple and effective strategy to fabricate the bending-durable membrane-electrode assembly for bendable polymer electrolyte membrane fuel cells (PEMFCs) by simply coating conventional carbon papers with manually fabricated silver nanowires (Ag NWs). Due to the high stretchability and flexibility of Ag NWs, we expect that the introduction of Ag NWs to carbon fibers would relieve the increase of ohmic and charge transfer resistances derived from the disconnections between each carbon fiber and the resulting decrease of electrical conductivity by repeatedly bending the bendable PEMFCs. We find that by using Ag NWs as an added component to carbon paper, the performance of Ag NWs-applied PEMFC can be maintained after repetitive bending. Carbon papers with the Ag NWs also show higher performance than the PEMFC without Ag NWs in the previous research. From the electrochemical impedance spectra of Ag NWs-coated PEMFC, it is clearly demonstrated that the coated Ag NWs effectively connect between carbon fibers and thereby play a role as a good buffer medium when carbon fibers are disconnected by mechanical bending. Highlights • Bending-durable polymer electrolyte membrane fuel cell was realized. • Gas-diffusion layer was simply coated with percolated silver nanowires. • Fuel cell with silver nanowires showed high durability after repetitive bending. • Silver nanowires maintained electric connection between disconnected carbon fibers. [ABSTRACT FROM AUTHOR]

A traditional system-level thermoelectric model requires enormous computing power and time for simulation analysis, especially when multiple optimization algorithms are combined. This paper initially proposed a comprehensive surrogate mode for the accurate modeling, field analysis, and fast optimization of thermoelectric generators. The surrogate model is made up of an artificial neural network (ANN) and a conditional generative adversarial network (cGAN), which can achieve a prediction accuracy of 97 % and a structural similarity (SSIM) of 0.954. Using a twisted tape annular thermoelectric generator (TT-ATEG) as an example, the generalization capability of the comprehensive surrogate model is demonstrated by studying the change of the twisted tape geometry parameters on the output performance and field distribution of the annular thermoelectric generator. The combination of the surrogate model and NSGA-II achieves fast optimization of key parameters under different working conditions, and the computational efficiency is improved by 99.97 %. Meanwhile, the cGAN part can predict the pressure and heat flow fields within 5s to provide intuitive visual feedback. The trained surrogate model requires less computer arithmetic power compared to the traditional multi-physics field simulation software. The successful application of the comprehensive surrogate model in this work provides a new solution idea and an optimization method for system-level TEG. • A comprehensive surrogate mode for performance prediction and optimization. • Surrogate Model Integrates ANN for Data-Based and cGAN for Image-Based Modeling. • Data-based performance computational efficiency improved by 99.97%. • Rapid physical field visualization provided within 5 seconds. [ABSTRACT FROM AUTHOR]

Abstract Long term electricity consumption forecasting has been extensively investigated in recent years in different countries due to its economic and social importance. In this context, the long term electricity consumption projections of a country or region are highly relevant for decision-making of companies and organizations operating in any energy system. In this paper, it is proposed a methodology that combines the bottom-up approach with hierarchical linear models for long term electricity consumption forecasting of a particular industrial sector considering energy efficiency scenarios. In addition, the Bayesian inference is used for model parameter estimation and, enabling the inclusion of uncertainty in the forecasts produced by the model. The model was applied to the Brazilian pulp and paper industry and it was able to capture the trajectory of the real consumption observed during the 2008–2014 period. The model was also used to generate long term point and probability distribution forecasts for the period ranging from 2015 until 2050. Highlights • Bottom-up Bayesian extension for the long-term electricity consumption forecasting. • The proposed model combines the bottom-up approach with hierarchical linear models. • The proposed model considers energy efficiency scenarios. [ABSTRACT FROM AUTHOR]