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Mitigation of global warming, energy security and industrial competitiveness urge the energy-intensive pulp and paper industry (PPI) to transform energy use practices. This study investigates how the PPI has responded to the need for the energy transition in the 2000s. Finland and Sweden as forerunners of energy-efficient operation and decarbonization of the PPI are used as target countries. Understanding of changes in energy consumption is complemented using decomposition analysis (Logarithmic Mean Divisia Index Method) and the energy efficiency index approach. Analysis of companies’ investments in energy technologies is used for explaining changes in energy production. Evidence of significant development towards the more sustainable operation of the PPI was found. Energy consumption per produced unit has decreased, i.e., energy efficiency has improved. Fossil fuels have been partially replaced with bio-based alternatives. Thus, the CO2 intensity has decreased substantially. The generation of renewable electricity has increased in both countries. Examples of Finland and Sweden indicate that the PPI has great potential to contribute to CO2 emission reduction worldwide in the future as energy efficiency can be further improved, and the share of fossil fuels can be decreased increasing the use of biofuels and self-generated green electricity at least in kraft pulp mills.

The advancement in plastic and plastic based products in last two decades has imposed a serious threat to the environment. This has led to an increase in the demand for sustainable and biobased products. Paper and paper products are good alternatives to their plastic counterparts. A key element of paper industry is the raw material (wood, bamboo and nonwood agricultural residues such as bagasse, straws etc.) from which pulp is produced. The pulp is then utilized for production of paper. There are many pulping processes to prepare pulp of various qualities. For fine grade pulp, chemical pulping is used. The chemical pulp is produced by soda, kraft and sulphite pulping processes. However, for newsprint grade pulp, stone ground wood (SW), thermomechanical (TMP), chemi-thermomechanical (CTMP), chemi-mechanical (CMP) or refiner mechanical (RMP) corresponding pulping processes are employed. The method of pulp preparation (pulping process) consumes large amount of energy and chemicals. A new pulping process with electron irradiation using biowaste (bagasse) as a raw material is discussed in this work. Bagasse pulping process is found to reduce about 50% of energy consumption during pulping process. The process is referred to as ‘ECTMP’ (Energy Efficient Chemi-Thermo Mechanical Pulping). The paper produced from aforesaid method also reflected no loss of strength properties with respect of TMP reference pulps. Henceforth, preliminary calculation based on experimental results shows that the proposed bagasse ECTMP process explored the scope of energy savings of the order of 50%.

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.

Green Energy efficiency is becoming more important because of the resulting cost reduction and image of green society which helps to enhance competitiveness in a globalized green market. Pulp and paper manufacturing is a large-scale industry which is generally regarded as important for national development. The Pulp and Paper industry consumes approximately 2.5% of total industrial energy consumption in Thailand by 44 factories distributed throughout the country. Therefore, energy efficiency improvement can play a significant role in the industry. Investigations of the cost effectiveness of energy efficiency measures and technologies using bottom-up Conservation Supply Curve (CSC) in the pulp and paper mill process are required. This study examines the concept, methodology, and the usefulness of the energy conservation supply curve, and the potential to create the appropriate energy policies to the Thai Pulp and Paper Industry.

We examine the efficiency of Brazilian pulp and paper companies in the production of pulp and bioelectricity using an output-oriented data envelopment analysis. We assume that pulpwood volume, energy consumption, installed capacity and number of workers are the inputs to generate pulp and bioelectricity. We conduct this analysis by first determining the traditional efficiency scores, and secondly calculating a composite index of efficiency to rank the performance of pulp and paper companies. We also conduct a post-efficiency analysis to gauge the impacts of externalities and other related variables on the efficiency in pulp and bioelectricity production. Our results suggest that pulp and paper companies are efficient in pulp and bioelectric production, reaching an average efficiency and composite index of efficiency of 0.9776 and 0.8291, respectively. The post-efficiency analysis suggests that pulp and paper companies could minimally decrease their adjusted efficiencies by increasing the total forest area, power capacity, and outsourced employment. On the other hand, the adjusted efficiency in the production of pulp and bioelectricity might not be statistically impacted by higher socioeconomic levels.

In recent years, the pulp and paper industry has changed a lot and products have been constructed in quite different methods using new technologies. It can be due to the emergence of challenges and constraints such as shortage of raw materials, energy consumption (fossil fuels, electric, etc.), management of the resulting pollutants, environmental issues, ongoing legal requirements and cleaner production strategies. In Iran, the pulp and paper industry's technological development is not keeping pace with global growth. Iran's pulp and paper mills supply a small fraction of domestic market. The reasons can be due to old technologies being used in factories, aging machinery, low productivity of production systems and lack of coordination with modern technologies. It leads to low-quality of paper products and willingness to buy local products. The aim of this study is to select the most appropriate technologies in the pulp section, due to high impact of pulp quality on the quality of final paper. Using a 2-filterd fuzzy decision-making, hierarchical structure of research is designed to assess technological alternatives according to the selected criteria. Findings show that after passing through two filters, Kraft method was chosen as the most appropriate method. The Kraft process has still many advantages like the high quality of the produced pulp and self-sufficiency in energy supply. This framework offers an appropriate procedure for identifying and selecting technologies that has not been used in past researches. Using this framework facilitates using a clear procedure for evaluating and selecting technology and prevents future losses for organizations.

International audience; An energy audit is a primary step toward improving energy efficiency at the facility level and ensuring a clean production. The pulp and paper sector is one of the most energy-intensive industries in Morocco. This article aimed at identifying energy conservation opportunities at a Small and Medium-sized paper industry. The audit results together with their financial viability are presented regarding the analysis of energy consumption and electrical quality issues. The paper introduces an action plan for a more efficient energy use of some specific applications such as furnaces and compressed-air installations as well. The recommended energy efficiency measures have the potential of saving about 347.85 MWh of electrical energy and 101.78 MWh of thermal energy corresponding to reductions of 11.48% and 2.22%, respectively. The total investments related to the application of the action plan is approximately 290.53 kMAD and the global payback period does not exceed one year. It was also shown that a total quantity of 283.39 t of CO2 emissions can be saved annually.

China's paper industry accounts for a larger proportion of the global paper industry and consumes large amounts of energy. Energy conservation and pollution reduction of the industry have become the focus of China's national development strategy. Energy efficiency is an important index which directly determines the amounts of energy consumption and pollution emissions. To understand the energy efficiency evolution of China's paper industry, this paper establishes an input-output data of the paper industry for 29 provinces in China and applies DEA method and econometric models to estimate and comprehensively discuss the energy efficiency issues based on the framework of total factor efficiency. Our results indicate that China's paper industry has a large energy saving potential even though its energy efficiency has improved during the period 1990–2013. The saving potential is about 65% under the meta-frontier and 44% under the group-frontier. Moreover, there are significant differences between different regions in production technology and energy efficiency. The performance of eastern China is better than other regions. But the technology gaps between the different regions are shrinking and converging over time. Finally, some policy recommendations are proposed to improve the energy efficiency of the industry.

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 CO2 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 CO2 emissions. CH4 generated from sewage treatment accounted for 9–11% of the total carbon emissions. The CO2 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.

To reduce energy use and achieve a low carbon production in pulp and paper industry (PPI), it is essential to improve energy efficiency in pulp and paper production. In this study, the energy savings from the PPI were estimated based on a techno-economic analysis by EAGER tool for PPI at the factory level. The structure and implement procedure were introduced initially. Two typical pulp and paper mills from China were determined to estimate the impact of selected energy efficiency technologies (EETs) on energy savings as the cases in the base year. One Factory (A) only produced paper products (i.e. corrugated paper and Kraft linerboard) while the other Factory (B) also produced market pulp besides sack paper. In totally 22 selected EETs were applied to assess their saving potential in Factory A, and 29 measures were applied in Factory B. The results show that 2290 TJ and 1179 TJ of final energy could be saved annually in Factory A and B, corresponding to reduction of 29.4% and 13.6% total energy consumption respectively for the case factories. The CO2 reduction potential was 32.3% for Factory A compared with that of 16.6% in Factory B. It suggests that the pulp and paper mills should encouraged to use this method estimating energy saving potential, and improve their energy efficiency with suggested measures in order to reduce energy consumption and related carbon emissions further in the coming years.

The pulp and paper industry accounts for approximately 5% of total industrial energy consumption and contributes 2% of direct carbon dioxide (CO2) emissions from industries. World paper and paperboard demand and production are increasing significantly, leading to an increase in this sector's energy use and CO2 emissions. Although current studies identify a wide range of energy-efficiency technologies that have already been commercialized for the pulp and paper industry, information is limited or scattered regarding new energy-efficiency technologies that are not yet fully commercialized. Development of emerging or advanced energy-efficiency technologies and their deployment in the market will be crucial for this industry's mid- and long-term energy saving and climate change mitigation strategies. This paper compiles available information on energy savings, environmental and other benefits, costs, and commercialization status for 25 emerging technologies to reduce the energy use and CO2 emissions. The purpose is to provide a well-structured comprehensive review on these emerging energy-efficiency technologies for engineers, researchers, investors, policy makers, pulp and/or paper companies, and other interested parties.

Pulp and paper production, an energy-intensive process, is among the main light industries contributing to energy saving and pollution emission reduction in China. The improvement of energy efficiency is essential for energy consumption and sustainable development. This study analyzes the negative factors in the pulp and paper sector by calculating energy efficiency from the lengthways time and investigating the gap between China and foreign countries through a horizontal comparison. Accordingly, energy efficiency has increased in the Chinese pulp and paper industry with years of efforts, but its transformation remains unclear. Furthermore, the energy-saving potential, energy cost saving, and carbon dioxide emission reduction in the pulp and paper industry are evaluated according to the Twelfth Five-year Plan (2011–2015). The results show that the pulp and paper industry has further capabilities for energy-saving and carbon dioxide emission reduction by improving energy efficiency in China, resulting in great economic benefit. In brief, new technology and energy structure adjustment are long-term strategies for energy conversation, with changes in the scale of mills expected to provide huge opportunities to improve energy efficiency in China within a short period.

Straw pulp in China, which is the world's largest producer of this material, suffers from water and energy shortages during its entire life cycle. However, limited systematic studies have focused on these issues, and decision makers need be provided with improvement methods for the environmental performance. Thus, an impact-oriented energy and carbon coupled water footprint analysis was conducted in this study based on ISO standards. Results showed that the impact of energy consumption and carbon emissions exceeded that of water footprint. Carcinogens, non-carcinogens, and freshwater ecotoxicity also played effective roles in improving the environmental performance. Optimizing key indirect processes, including chemicals production, steam preparation, electricity generation, wood pulping, and fertilizer recovery, dominated the reduction in environmental burdens. Direct freshwater consumption and wastewater disposal played additional effective roles in controlling water footprint. The water network was thus optimized by a water pinch analysis to decrease the freshwater consumption and pollutant emissions by maximum values of 91.5% and 99.7% after optimization, respectively. Meanwhile, carbon dioxide, methane, chromium, arsenic, mercury, titanium, copper, strontium, total nitrogen, total phosphorus, BOD5, and COD were the main pollutants. Overall, the environmental impact can be further reduced by diminishing coal power ratio in national energy structure, adopting recovered steam, and considering multistage regeneration water network to cope with different water use demands.

The purpose of this study was to assess the environmental impacts of the Norwegian pulp and paper industry, considering the production of pulp fibres and printing paper. The pulp fibres included in this study are thermo-mechanical pulp and kraft pulp fibres, which differ with respect to the energy consumption and chemicals used during production. The assessed paper grades were super-calendered paper and newsprint. The study was a cradle to gate approach, and corresponds to an attributional life cycle assessment (LCA). The LCA was based on data collected from main pulp and paper producers in Norway. Importantly, aspects related to the increasing use of mineral fillers in the production of newsprints were assessed. The results showed that a reduction of more than 18% climate change impact (kg CO2 eq.) was achieved by increasing the fraction of fillers, in the newsprint furnish. Furthermore, the total climate change impact reduction depended on the applied energy mix. Assuming that the production of printing paper was based only on Norwegian energy mix, yielded a reduction of the climate change impact by more than 44% in 2011, compared to the production based on Scandinavian and European energy mix. Additionally, the input and output transport contributed to more than 20% impact in several cases. We thus concluded that the estimated environmental impacts were affected by; i) the furnish composition of a given paper quality, ii) the input and output transport and iii) the use of different primary grid energy sources.

With the advent of the Paris Climate Agreement and China ratifying it recently, there is a need to adopt a diversified approach to address climate change; this is especially the case of promoting residential energy conservation. This study is one of the first household energy intervention studies that focuses on the comparison of two message delivering means, paper-based versus instant messaging tool, as a platform for sharing energy-saving tips and engaging households to save energy in China. Conducted in several communities in Hangzhou, Zhejiang Province of China, the effectiveness of using a widely used application known as WeChat in promoting household energy conservation is compared with that of using stickers. It was found that WeChat is the most effective is reducing monthly consumption, but the effects are short-lived. Comparatively, using stickers as a mean of engaging households produces more sustained results in terms of energy savings. This study also provides evidence to correlate the changes in energy consumption behavior with personal perception of one’s responsibility and quality of life. That is, certain behavior can be triggered if residents are willing to impose energy ration in their households or are given more opportunities in the form of local programs that enable them to have more practices in energy conservation.

The objective of this paper is to estimate the energy saving potential in China's paper industry by determining energy intensity under different scenarios. Cointegration model and stability test are applied to formulate the equilibrium equation. Results show that energy price, industry structure, profit margin and technology have significant impact as they are negatively correlated to changes in energy intensity. Three scenarios (BAU (business as usual), intermediate and active) are designed to estimate the future trend of energy intensity in paper industry. In 2010, the energy intensity (energy consumption per unit of value added) was 4 tce/10,000 RMB, and by the scenarios it is expected to considerably decline. According to the BAU (business as usual) scenario, the energy intensity will decrease to 2.56, 1.43 and 0.70 tce/10,000 RMB by 2015, 2020 and 2025, respectively. With respect to the intermediate scenario it is expected to drop further to 0.44 tce/10,000 RMB. Yet by the active scenario, the energy intensity is expected to considerably decline to 0.36 tce/10,000 RMB by 2025. Using the BAU forecast as a baseline, the quantity of energy savings is estimated to be 185.6 billion tce by 2025. Considering this important potential, we also provided some policy suggestions.

Under the dual pressure of energy consumption and environmental pollution, mankind hopes to develop clean and renewable alternative energy, and the rapid development of fuel cells meets people's demand for energy-efficient power systems. The emergence of portable micro energy systems represented by microfluidic fuel cells, such as paper-based microfluidic fuel cells, has greatly enriched the means of medical detection to better cope with the threat of disease transmission. In this work, the numerical simulation method is innovatively introduced to study the paper-based microfluidic fuel cells. Both transient and steady-state modes are employed to demonstrate the whole operation process of the paper-based microfluidic fuel cell. In addition, the different structural parameters, including electrode spacing, the distance between electrode and inlet, channel thickness, and electrode length, are also investigated their influence mechanisms on cell performance. Results show that the increase of most structural parameters decreases cell output power in different degrees. Even on the premise that increasing channel thickness has a positive impact on the output power, the fuel utilization still shows a downward trend. These conclusions provide theoretical support and reference for future optimization work and accelerate the development of microfluidic fuel cells.

Pulp and paper mills receive much attention from environmentalist and authority due to their impact on natural resources, particularly in water and energy consumption. Many research works have been reported for water and energy savings for the pulp and paper mill. However, none of them were targeted at the brown stock washing system (BSWS), where significant water and energy are consumed to perform pulp cleaning and black liquor concentration. This paper presents an optimization model aiming for simultaneous water and energy saving for BSWS in the pulp and paper mills. A mixed integer non-linear programming (MINLP) model has been developed to optimize the water network design. The synthesized water network results in significant reduction in energy and water consumption. Sensitivity analysis is performed to analyse the relationship between washing efficiency and utilities (water and energy) consumption.

To improve energy efficiency of a Paper & Pulp industry, full capacity utilization of the processing equipment and diverse energy source utilities are promoted, while same time processing of diverse raw materials, meeting of strict processing time requirements, seamless material flow and obtaining required product quality are important concerns to be fulfilled. This is similar to a resources management problem while energy is considered as one of the measurable resources, wherein estimation of energy consumptions is crucial/complicated aspect. Discretized form of energy consumption (approximate energy consumed by unit amount of intermediate products at different intermediate processing stages) concept is utilized here with discrete event simulation for consumed energy estimation/analysis. The research deals with a real time working Paper & Pulp industry resource management problem, wherein overall energy consumption rate and production rate were analyzed for some commonly occurring situation of efficiency reduction of the processing station(s). Energy efficient solutions are evaluated with varying production flow (varying the percentage of raw material) and resources management options (turning on/off paper machines). Energy efficient solution which ensures minimum loss in production rate and minimizes disturbances in material flow is suggested for implementation.

Much research has been focused on maintaining stable humidity conditions in buildings housing heritage collections while reducing energy use. Moisture buffering by collections themselves can have a marked effect on the stabilisation of relative humidity (RH), the key parameter for preservation. Modelling of moisture transport using COMSOL Multiphysics was applied to transform three-dimensional paper and wooden objects into their one-dimensional representations, without changing the moisture uptake and release characteristics. The results were coupled to the modelling of indoor microclimate and energy consumption in collection storage spaces with the use of WUFI ® Plus software. The study revealed the crucial impact of air exchange rate of the building on the stability of indoor RH and the humidification and dehumidification loads required to maintain it. In the adequately air-tight library store, a sizeable paper collection was found to reduce the RH fluctuations from ±9% to ±6% around the yearly average and the energy consumption due to the humidification and dehumidification load by 38% when compared with the empty space, for a high-quality climate control scenario. In turn, a wooden collection, occupying a realistic fraction of a museum store was not large enough to significantly narrow down the RH variations and reduce the energy consumption.

E RNEST O RLANDO L AWRENCE B ERKELEY N ATIONAL L ABORATORY Potential for reducing paper mill energy use and carbon dioxide emissions through plant-wide energy audits: A case study in China Lingbo Kong, Lynn Price, Ali Hasanbeigi China Energy Group Environmental Energy Technologies Division Lawrence Berkeley National Laboratory Huanbin Liu, Jigeng Li State Key Laboratory of Pulp and Paper Engineering, South China University of Technology Reprint version of journal article published in “Applied Energy”, Volume 102, February 2013 March 2013 This work was supported by the China Sustainable Energy Program of the Energy Foundation through the U.S. Department of Energy under Contract No. DE-AC02- 05CH11231.

The pulp and paper industry is placed in a unique position as biomass used as feedstock is now in increasingly high demand from the energy sector. Increased demand for biomass increases pressure on the availability of this resource, which might strengthen the need for recycling of paper. In this study, we calculate the energy use and carbon dioxide emissions for paper production from three pulp types. Increased recycling enables an increase in biomass availability and reduces life-cycle energy use and carbon dioxide emissions. Recovered paper as feedstock leads to lowest energy use (22 GJ/t) and CO2 emissions (−1100 kg CO2/t) when biomass not used for paper production is assumed to be converted into bio-energy. Large differences exist between paper grades in e.g. electricity and heat use during production, fibre furnish, filler content and recyclability. We found large variation in energy use over the life-cycle of different grades. However, in all paper grades, life-cycle energy use decreases with increased recycling rates and increased use of recovered fibres. The average life-cycle energy use of the paper mix produced in The Netherlands, where the recycling rate is approximately 75%, is about 14 GJ/t. This equals CO2 savings of about 1 t CO2/t paper if no recycled fibres would be used.

There has been much debate on the topic of whether stricter environmental regulations can promote environmental performance and economic performance at the same time. Different researchers have used different indicators to measure environmental performance and economic performance in their empirical studies. However, it is a surprise that few studies have checked the relationship between environmental regulation and eco-efficiency, as the latter is widely regarded as a quite powerful tool of considering ecology and economy together. In this study the background is the implementation in 2003 of the Stricter Discharge Standard (SDS) in Shandong Province's Pulp and Paper Industry (SPPI), compared to the national standards of China. The stricter regulations were intended to promote corporate change from passive management to active control and from end-of-pipe treatment to cleaner production. This study investigated the eco-efficiency trends of SPPI from 2001 to 2008 in three fields: water efficiency, energy efficiency and environment efficiency. A "de-linking" and "re-linking" tool was used to attain a further evaluation. The study showed that with the implementation of stricter regulation most of the efficiency indicators (except CO2 emission and energy consumption) had achieved significant improvements, and the overall environmental performance trends of SPPI showed it to be more sustainable. However, the study also found that it was not enough to address a single indicator in the environmental regulation of the pulp and paper industry. More holistic eco-efficiency indicators need to be further considered and introduced to the industry as the next step to create true sustainable development. (C) 2010 Elsevier Ltd. All rights reserved, (Less)

Developments in paper machinery have produced or are producing solutions to enhance water removal and improve paper properties. These include impingement drying and impulse technology. However, both methods also use energy in some other form than steam to bring about drying. On paper machines, where a large share of conventional drying is replaced with new technologies, the energy system should be reconstructed to achieve the increased power-to-heat ratio with better efficiency than with the conventional steam power plant. CHP-solutions based on diesel and gas turbine processes were compared against the steam boiler based process to assess their potential for increasing thermal efficiency in combined power and heat production. The calculated results confirm that the efficiency of heat and power production can be significantly increased in the selected cases by utilising either diesel or gas turbine technology.

Biological treatment of pulp and paper industry wastewater is made effective by giving a simple electrochemical pre-treatment. Biodegradability index is found to be improved from 0.11 to 0.46 by a short (6.9 min) treatment in mild conditions (current density: 112.9 A m−2, pH 7.3). The optimal operating point for maximum biodegradability has been found out using response surface methodology (RSM). It is also noticed that there exists an optimal operating point for maximum biodegradability. The specific energy consumption and current efficiency figures at the optimal condition are also promising. Moreover there is considerable reduction in the pollutant load (COD removal: 55% and color removal: 87%). Performance of the process at this operating point has been validated by running biological treatment. Considerable reduction in the requirement of biological reactor volume can be expected by giving such a simple electrochemical pre-treatment.

A degraded hemicellulose obtained from degumming liquor of ramie fibre was used as an additive during the beating operation of jute-stick pulp. Pulp properties, such as freeness, beating energy, etc., and the strength properties of the paper sheets were evaluated. It was found that the additive had a significant effect in reducing the energy consumption during the beating operation and in improving the strength properties of paper sheets made from the pulp.

Most of the energy consumption in paper machines takes place in the dryer section. The purpose of the heat recovery system is to reduce the consumption of primary energy in the paper machine by utilising waste energy from the process in an economically profitable way. To provide the necessary information and computer tools to aid engineering designers, experimental and theoretical investigations have been carried out for a scrubber. Experiments were conducted in a 0.710 m diameter and 3 m high column. The experiment was based on the exchange of mass and heat transfer between humid air which is moving from the bottom to the top of the column and drops which are raining down. A classical physical model has been developed to predict the heat and mass transfer between phases. Experimental results agree well with the prediction. The physical model was used to predict the optimum operational condition for an industrial-type scrubber.

A method is presented for cross-country, cross-time comparison of energy efficiency developments in the manufacturing industry. The method is based on the use of physical production data as a measure of activity growth for the manufacturing industry. The methodology was applied to the pulp and paper industry of eight countries of the Organization for Economic Cooperation and Development (OECD). With the methodology it is possible to follow energy efficiency developments, separately, for fuel and electricity consumption. Between 1973 and 1991, the production growth in the pulp and paper industry in the analysed countries would have resulted in an average increase in the primary energy consumption by 42%. Changes in the product mix had hardly any effect on the primary energy consumption. Because of energy efficiency improvements, the growth of primary energy consumption was limited to only 16%. The average annual efficiency improvement amounted to 1.6%. The methodology presented enables physical energy efficiency comparisons to be made between countries without the need for data at the process level.

This paper deals with energy end-use models for pulp, paper, and paperboard mills. The models are consistent with data published in the U.S. Department of Energy's 1991 Manufacturing Energy Consumption Survey (MECS). A graphical framework for depicting these energy flows is presented. Development of these models is a key step in creating energy process-step models for pulp, paper, and paperboard production. The applicability of the modeling approach and framework to other industries is discussed.

In this work, a new framework for control of power flow of an energy storage is proposed. As part of the framework, an advanced controller for manipulating the power flow of an energy storage system, a photovoltaic (PV) source, and the utility grid is developed. The new controller relies on the Model-based Predictive Control (MPC) concept. The proposed controller realizes an optimal control scheme that maximizes the local self-consumption of renewable energy source. At the same time, the energy consumption supplied by the electric grid is minimized subject to its price posted in the grid. The presented approach is evaluated through computer-aided simulations using data available from a real installation in Switzerland. The data consists of photovoltaic panels, industrial building as a load as well as a battery energy storage system (BESS).

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.

Viable alternatives to conventional newspapers, such as electronic papers, e-papers or e-readers, are intended to have many of the qualities of paper, such as reading using reflective light, high resolution, 180° viewing angle. It has been suggested that the environmental impact of e-paper can be lower than for printed and internet-based newspapers. However, in order to find the facts of the matter, a thorough life cycle perspective covering raw material acquisition, production, use and disposal should preferably be used to study the environmental performance of the different products. A screening life cycle assessment was performed to describe the potential environmental impacts of two product systems; printed on paper and tablet e-paper newspapers. Results show that the most significant phase of the life cycle for both product systems was the production of substrate or platform. Accordingly, key aspects that may affect the resulting environmental performance of newspaper product systems were for the printed newspaper number of readers per copy and number of pages per issue and for the tablet e-paper newspaper lifetime and multi-use of the device. The printed newspaper in general had a higher energy use, higher emissions of gases contributing to climate change and several other impact categories than the tablet e-paper newspaper. It was concluded that tablet e-paper has the potential to decrease the environmental impact of newspaper consumption. However, further studies regarding the environmental impact of production and waste management of electronic devices and internet use, as well as more comprehensive assessment of toxicological impacts are needed. As the data on the electronic devices becomes more comprehensive this may prove to be a major limitation of electronic newspaper systems. Developers are suggested to strive towards minimisation of toxic and rare substances in production.

A mini-computer installed in a caravan has recently been started by the technical assistance team of the French Pulp and Paper Research Institute with the purpose of making on-site mass and energy balances around paper machine dryers. The methods used for elaborating wet air, steam and condensates parameters are first described. The main features of the designed software (adaptability to different machine structures) are then presented applied to the case of an average industrial paper machine. The short delay before getting elaborated process data and balance computations largely enhance the possibilites of on-site trouble-shooting of the team.

Drying is a very important phase of papermaking. Both the energy consumption and investment costs required by this process are high. This paper describes a method giving systematic analysis of industrial drying sections during their run and based on a mathematical model of paper cylinder drying. Working on measurements data, it is possible to compute the heat and mass transfer coefficient values to get the complete identification of the considered drying section. Then, it is possible to test by simulation, the effect of new investments (increasing the number of cylinders, moving the size-press location, etc) or of operating point changes (increase of steam-pressure or moisture content at the entrance... etc) on the machine production and on the steam consumption. This method has been used for an industrial printing paper machine. Computer simulations have allowed to get the optimal size-press location in the drying section and the machine speed variations obtained after the increase of the number of cylinders and this for three different basis weights.

Integrating the acetone-butanol-ethanol fermentation with pervaporation or gas stripping for in situ product recovery is considered as an effective way for biobutanol production, and the following downstream distillation sequences have been extensively investigated. Whereas, there are still no comprehensive comparison of the reported distillation processes in sight of the techno-economic feasibility. In this study, three alternative distillation sequences that contains a decanter and recycle loops are selected and compared by steady-state simulation. ABE condensates collected by ISPR, with different solvent concentrations and constituents, are considered as the feed stream of distillation. The impact of ABE ratio on energy consumption and techno-economics of the selected distillation sequences are analyzed. Results indicate the separation performances, including the energy requirement and economics, are highly influenced by the distillation sequence. Compared with other Scenarios, when feeding the extreme ABE constituents within the confidence interval, the sequence that consisted of three columns and a decanter with two recycle loops exhibits the lower energy requirement (7.99 MJ/kg) and TAC (4.15 × 106 US $/yr). The current work guides to the designation of suitable ISPR-distillation process in future works.

The article presents results of research on commercially used cutting mechanisms of low-power (about 10 kW) wood size reduction machines driven by small engines. The energy consumed was determined based on work demand, showing that two-cylinder cutting mechanism consumes less energy than disc cutting mechanism and drum cutting mechanism when wood size reduction various species of wood, within the cross-section range from 10 × 10 mm to 50 × 50 mm. The main application of the tested machines is the reduction of branch volume when maintaining the infrastructure of urban green areas, in order to facilitate their transport. The average increase in energy consumption required for the size reduction of a single 2-m-long timber beam relative to the most energy-efficient mechanism (two-cylinder cutting mechanism) may range from 369% to 478%, while the average energy consumed during 1 h of continuous wood size reduction machines operation may increase relative to the least energy-efficient mechanism from 80% to 188%. The average productivity when reducing the size of the wood of the tested machines depending on the cutting mechanism ranges from 0.47 tons/h to 0.06 tons/h. The greatest productivity is characterized by the two-cylindrical mechanism cutting 0.88 tons/h.

A pretreatment process is a preliminary stage to alter the recalcitrant structure of lignocellulosic biomass for enhancing its digestibility. An evaluation of the energy consumption and the environmental restrictions of the pretreatment step is required to develop a feasible eco-friendly process for industrial implementation. In this study, a combined alkaline-mechanical fractionation of rice straw for fermentable sugar (FS) production was developed with the objectives of i) evaluating energy efficiency and ii) addressing the sustainability of technology. The maximum fermentable sugar production was 0.54 kg/kg rice straw with an enzymatic hydrolysis efficiency of 97.34%. Furthermore, the results indicated that the pretreatment by 5% NaOH followed by mechanical size reduction provided the highest energy efficiency of 0.35 kg of FS/kWh with 94.44% glucose recovery, which also provided the lowest waste generation of less than 0.1 kg of waste/kg FS. These experimental results suggest that the combined alkaline-mechanical fractionation could effectively increase total FS yields and could be a promising pretreatment technology for an eco-friendly and sustainable pretreatment process integrated into a biorefinery platform.

The selection of a proper drying method can play a vital role in reducing the energy consumption and the quality of the final product. In this study, three dryers, including conventional refractance window (CRW), solar refractance window (SRW) based on the photovoltaic-thermal system, and hot air (HA) dryers, were used to dry the Aloe vera gel. Experiments were carried out at four levels of temperature (60, 70, 80, and 90 °C) and three levels of thickness (1, 2, and 3 mm) for the puree product. An increase in temperature and a decrease in thickness reduced specific energy consumption, specific heat consumption, specific heat utilization, pollutant emission, and social costs derived from the pollutant. The results showed that the SRW dryer significantly improved the energy and drying parameters compared to the HA method. The pollutant emission and social costs in the SRW dryer were zero, while these values were significant using the CRW and HA dryers. The highest amounts of antioxidant potential, phenol, flavonoids, and glucose were 98.61%, 0.0435%, 0.0103%, and 19.28% (mg/g dry matter), which were obtained at 60 °C and 3 mm thickness using the SRW/CRW dryers. However, these values were 76.69%, 0.0246%, 0.0039%, and 16.31% (mg/g dry matter) using the HA dryer. In general, according to energy consumption and drying parameters, the best experimental results were obtained at temperatures between 70 and 80 °C and a thickness of 2 mm.

In this study, two approaches for biodiesel production from microalgae, one through a dry route (using dried microalgae) and another through a wet route (using wet microalgae), are critically assessed. Analysis suggests that although both routes yield biodiesel of similar quality, there is a considerable difference in overall energy consumption, energy-intensive steps, and size of equipments for processing the same amount of lipids. This review depicts that both routes demand significant amount of energy, i.e. up to 120 MJ per kg of biodiesel that amounts to nearly three times the energy obtained from it. Also, the cost of production for one kg of biodiesel is high, i.e. up to $25 and $12 in dry and wet route respectively. This review article aims to present comprehensively and coherently the technical aspects of these two routes and their attributes in terms of energy consumption, manufacturing cost, and capital investment.

Black soldier fly larvae containing high lipids had been considered an novel sustainable feedstock for lipid extraction to biofuels. The insect lipid was extracted with microwave assisted solvent extraction method. The energy consumption of this way was analyzed to determine the feasibility of the lipid extraction process. The comparison of the effects of different extraction conditions (dehydration methods, water content, extraction temperature, extraction time, equipment power, and solute-solvent ratio) on the energy consumption of lipid extraction from the energy insect was investigated systematically. The dewatering of the insect biomass was the most energy consuming step via a dry extraction method in this paper, constituting about 40–80% of the total energy consumption demand. Within the ranges of extraction factors values compared in this analysis, the microwave radiation powder and lipid extraction temperature had a pronounced effect on the total energy consumption in the ranges of investigated parameter. At last, the lipid extraction yield-dependent evolution of energy consumption for different extraction conditions was also investigated. Anyway, the economic and environmental aspects of lipid extraction from the energy insect needed to be further improved for its large scale implementation in the future.

The impact of urine diversion on the biological treatment processes at a decentralized wastewater treatment plant (WWTP) was investigated. BioWin software was used for the simulations, and the model was firstly validated with data from a real WWTP. The simulations showed that upto 82 % N, 30 % P, 6% chemical oxygen demand (COD) load to the WWTP can be reduced by complete urine diversion but effluent N reduction was notable up to 75 % urine diversion. Under the current WWTP operating conditions, the simulations suggest that 33 % of aeration energy can be saved by 90 % urine diversion. Direct N2O and CO2 emissions in the treatment processes can also be reduced by 98 % and 25 % respectively. Indirect green house gas emissions can also be reduced by 20 %. Overall, the reduction in the discharge of nutrients and in the operation of blowers was found to contribute to a 22 % reduction in the operating costs (on energy consumption and nutrient discharge).

Bio-hydrogenated diesel (BHD) is a second generation biofuel that can be produced from vegetable oil and hydrogen via hydroprocessing. BHD is considered as one of alternative and renewable energy. This work presents evaluation of environmental impacts of BHD produced from palm fatty acid distillate (PFAD) compared to fatty acid methyl ester (FAME). Greenhouse gas emission, energy consumption, and overall environmental impacts are assessed. System boundary is from palm oil cultivation to BHD production. The functional unit is defined as 1 kg of fuel produced at the plant. The results indicate that energy consumption of BHD-PFAD is 1.18 times higher than that of BHD-FAME, while giving GHG emission 13.56 times lower than that of BHD-FAME. The results of overall environmental impacts indicated that BHD-PFAD was 3.58 greater than that of BHD-FAME.

To achieve energy neutrality in wastewater treatment, reduction of energy consumption and renewable energy production has been proposed as a sustainable solution within circular economy. The performance of an anaerobic Continuous Stirred Tank Reactor (CSTR) digesting sewage sludge from a Chemically Enhanced Primary Treatment (CEPT) unit regarding organic carbon removal and renewable biogas production was evaluated under various Hydraulic Retention Times (HRTs). Anaerobic digestion of CEPT instead of primary sludge resulted in higher Chemical Oxygen Demand (COD) and Volatile Suspended Solids (VSS) removal efficiencies, i.e. 46-51% and 28–35% for CEPT sludge compared to 33% and 20% for primary sludge, respectively. Biogas production from CEPT sludge was constant and stable (0.15–0.16 L/L.d) at all HRTs examined, while biogas production was lower during digestion of primary sludge (0.06 L/L.d). The combination of CEPT, which concentrates organic matter derived from wastewater and minimizes oxygen consumption, and the anaerobic digestion of the CEPT sludge, which reduces energy consumption and generates renewable energy form non-conventional resources, provides a sustainable wastewater treatment practice towards circular economy. In a study performed for the proposed CEPT + CSTR scheme for the treatment of wastewater in a city with 50,000 population equivalent, the annual energy gain was estimated as 1,314,000 kWh.

The discharge of phenol-containing wastewater has become a crucial and health threatening environmental issue. In this paper, an electro-electrodialysis (EED) process was investigated to remove phenol molecules in the form of phenoxide ions, and simultaneously desalt the laboratory-prepared salty wastewater. The influence of applied voltage, sodium sulfate and phenol concentrations on the separation performance and energy consumption of the EED process was studied. More than 90% of the phenol could be removed, illustrating the feasibility of the EED process. The specific energy consumption for phenol removal was primarily influenced by the concentration and characteristics of the competitive anions, such as sulfate and hydroxide ions in the feed solution. An increase of phenol concentration reduced the specific energy consumption, while a higher salt concentration resulted in higher energy consumption. The EED process is more energy-efficient for treating wastewater with low salt concentrations and high phenol concentrations. These results can significantly enhance the application potential of this emerging separation process.

The paper devised a unified basis for energy recovery processes in municipal treatment plants based on sludge footprints. Emphasis was placed upon innovative energy recovery technologies to test whether energy neutrality could be sustained or even, net useful energy could be produced. In this context, it evaluated first the energy potential of municipal wastewater treatment plant based on sludge footprints: it adopted a unified perspective where energy recovery was considered as an integral part of energy conservation in sludge. Sludge footprints of different activated sludge configurations were first analyzed based on latest concepts of process stoichiometry and modeling. The performance indicators of process modifications were analyzed and interpreted for energy conservation for a wide range of sludge age between of 0.5–50 d. An influent COD level of 500 mg/L was adopted, also defining all significant COD fractions compatible with related characterization studies. The role of primary sedimentation was accounted for where applicable. Calculations showed that 1259 kcal/m3 (75%) to 379 kcal/m3 (23%) of COD energy could be preserved in sludge as the sludge age was increased between the range of 0.5–50 d. Conventional activated sludge (CAS) conserved around 35–40% energy, corresponding to 600–650 kcal/m3. Primary sedimentation boosted the overall energy conservation to 901–990 kcal/m3, corresponding to 54–59% of the available energy in sewage COD. As expected, energy recovery by means of anaerobic digestion (biogas), remained far below the energy consumption in the treatment plant. This study envisaged syngas production by means of high temperature pyrolysis as a novel alternative instead of sludge digestion. Pyrolysis revealed a potential to yield a net useful energy (positive net energy) of 0.08–0.49 kWh/m3 for systems operated at sludge ages of 2–10 d without primary sedimentation; much higher net useful energies of 0.33–0.59 kWh/m3 could be obtained in systems with primary sedimentation operated at sludge ages 2–14 d. The study provided conclusive evidence that the real problem in establishing energy neutrality in treatment systems was the low energy recovery of the conventional sludge digestion and not the level of energy conservation in the activated sludge process; therefore, the step forward should look for more effective energy recovery processes such as high temperature pyrolysis (syngas generation) or similar novel technologies.

Primary treatment is a major component in modern sewage treatment systems; and chemical enhanced primary treatment (CEPT) process can further enhance its performance for energy recovery or process improvement. With significant benefits on small footprint and sludge dewaterability, CEPT process has been selected and applied as the major wastewater treatment technology in Hong Kong. CEPT sludge, similarly in composition to typical primary sludge, is rich in organic contents and therefore can serve as a proper source for bioenergy production after anaerobic digestion (AD). The heating value of CEPT sludge can be higher than that of secondary sludge, which is mainly composed of slowly degradable organics and microorganisms. If neglecting energy consumed to produce the coagulant a CEPT-AD system shall drive the wastewater treatment process from energy-negative practice to energy-neutral or even energy-positive systems. This paper demonstrates some of the most important substrate-related features to increase the bioenergy production in the CEPT-AD system. Attentions have been paid particularly on the analysis of physiochemical characteristics of the CEPT sludge and their impacts to the biological system with heterotrophic species. An innovative sulfide oxidation process was presented with experimental evidence to overcome the potential problems of sulfide induced growth inhibition of methanogens. It was expected that the new process could reduce approximately 0.744 kWh/m3 of energy consumption in comparing with conventional activated sludge process without nutrient removal.

The objective of the present issue was to inquire the effect of ultrasound assisted convective drying on a thin layer of sunflower seeds. The process was carried out utilizing a hybrid chamber dryer, outfitted with an ultrasound generator with indirect transmission toward the material surface. Drying behavior was analyzed by drying time, effective moisture diffusivity (Deff), energy consumption (EC), water activity (aw), and total color change (ΔE). Independent variables of air temperature and ultrasound power determined the efficiency of sonication during drying. So that, ultrasound contributed to a noticeable increase in Deff up to 44.84%. Thereafter, a reasonable decrease was found in drying time, energy consumption, and total color change up to 40.85%, 32.95%, and 44.56%, respectively when collocating the variables of 35 °C, 3.5 m/s, and 2.4 W/g. The optimum drying condition in the pure convective drying domain was improved from 50.74 °C and 2 m/s to the condition of 40.64 °C, 2 m/s, and 3.932 W/g after sonication. In this point, significant reductions of 19.89% and 19.32% were observed in drying time and energy consumption. Optimization results confirmed that ultrasound intervention could provide an intensified and energy-efficient drying process, which generates sustainable and qualified dried seeds.

In this study, a few extractive distillation processes with ethylene glycol as solvent are proposed to separate high-purity ethanol and tert-butanol from industrial effluents, including direct ED, indirect ED and heat pump assisted indirect ED. All these processes are optimized with targeting minimum annual total costs by a sequential iteration algorithm. After that, a head-to-head comparison is completed regarding distributions of cost, energy and CO2 emission. The results showed that the direct ED is the most economical process reducing minimum annual total costs by 30.15 % than the heat-pump assisted indirect ED, while the latter is the most energy-efficient process saving energy consumption and CO2 emissions by 14.78 % and 21.79 % than the direct ED.

In biomass utilisation, size reduction caused by grinding is a critical procedure because it greatly changes the particle size and shape of the biomass sample, which greatly influences its energy conversion efficiency. Raw biomass is difficult to grind due to its fibrous nature and therefore needs to be pretreated before grinding. Traditional torrefaction pretreatment consumes more energy and changes the chemical composition of biomass. In this study, we select wheat straw with abundant yield in northern China as the biomass sample for testing and introduce a new freezing pretreatment method into the grinding procedure. This method incorporates the freezing of wheat straw with liquid nitrogen. We evaluate the performance of freeze grinding in terms of grindability, energy consumption, chemical composition and energy conversion efficiency, and compare it with that of torrefaction grinding to investigate the effects of pretreatment methods on wheat straw. Particle size and shape distribution are used to characterise grindability. Moreover, we improve sample preparation, image acquisition and segmentation methods to reduce the impact of particle agglomeration. Experimental results demonstrate that freezing as pretreatment improves the grindability and energy conversion efficiency, whilst reducing energy consumption and maintaining chemical composition of wheat straw.

An experimental-scale electrostatic precipitator (ESP) was built to investigate the influence of temperature and gas media on collection efficiency and energy consumption. High temperature was harmful to the performance of the ESP and had a considerable influence on large particles. The maximum collection efficiency was lower and energy consumption was higher under coal pyrolysis gas media than under air. Two improvement methods, namely, gas media conditioning and positive polarity power supply, were studied in this work. Both methods can improve the performance of high-temperature ESP under coal pyrolysis gas media. The improvement in collection efficiency under the effect of gas conditioning decreased and that under the effect of a positive power supply increased with the increase in temperature. Gas conditioning and positive power supply increased the maximum collection efficiencies of the ESP at 600 °C under coal pyrolysis gas media by 3.0% and 11.8%, respectively.