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Thermo-mechanical Pulping (TMP) is one of the most energy-intensive industries where most of the electrical energy is consumed in the refining process. This paper proposes the energy-saving refining optimization strategy by integrating the machine learning algorithm and heuristic optimization method. First, refining specific energy consumption (RSEC) and pulp quality identification models are developed using Artificial Neural Networks. In the second step, the developed identification models are incorporated with the Genetic algorithm to minimize the total refining specific energy consumption while maintaining the same pulp quality. Simulation results prove that a deep multilayer perceptron neural network is a powerful tool for creating refining energy and quality identification models with the model correlation coefficients of 0.97, 0.94, 0.92, and 0.67 for the first-stage RSEC, second-stage RSEC, final pulp fiber length, and freeness prediction, respectively. Findings confirm that the average total RSEC reduction of 14 % is achievable by utilizing the proposed optimization method.

Submitted: February 1st, 2021 ; Accepted: March 30th, 2021 ; Published: May 21st, 2021 ; Correspondence: clara.mendoza.martinez@lut.fi The coffee production chain is a potential source of residual biomass inherent to the high productivity that can contribute to the generation of value-added products. The residues from the coffee sector are typically disposed to landfill without treatment causing potential environmental inconveniences. Briquetting presents an alternative process to produce a uniform fuel with high energy density. Briquettes facilitates easy transportation, enables better handling and storage of biomass residues. Properties such as low equilibrium moisture content, high energy density and compressive strength were reported for different coffee-pine wood briquettes treatments. Moreover, understanding of the thermal properties of the briquettes during combustion is crucial to evaluate their final application. This research is the first study that investigates the combustibility properties and kinetic parameters of the thermal decomposition of briquettes from coffee-pine wood using differential and integral thermal analysis under non-isothermal conditions. Multivariate analysis of the collected parameters through principal components analysis (PCA), was implemented to reduce the dimensionality of the data. The desired profile in the combustibility is directly related to high temperatures and long burning times, thus, the tested briquettes displayed a significant combustibility potential, reporting peak temperatures and burnout times around 600 °C and 27 minutes, respectively. Activation energy kinetic parameter in the range of 12–42 kJ mol-1 and average reactivity of 0.14–0.22 min-1 , were also found. The results revealed the not thermally hard material to degrade when compared to biomasses typically used for combustion.

Biomass-derived activated carbons are promising materials that can be used in various applications. Current work investigates the possibilities of the cellulose-derived activated carbons in substituting the commercial alternatives for the supercapacitors’ electrodes with high efficiency, stable performance and relatively low cost. Hydrothermal carbonization (HTC) followed by chemical activation with KOH is used to convert cellulose into highly porous activated carbons. The effect of HTC parameters on the material porosity development and electrochemical properties of the electrodes is evaluated with several variations of the residence time and the weight ratio between cellulose and water during the pretreatment. The analysis shows that intensification of the HTC process (longer residence time and higher water/cellulose ratio) results in increase of the surface area of both hydrochar samples and subsequent activated carbons: with the highest surface area for the sample produced after 2 h HTC treatment with water/cellulose ratio of 6/1 – 2,645 m2 g -1 . As for the electrochemical analysis, the highest values of the specific capacitance are found for the samples produced from 2 h HTC treatment: 110.3 F g -1 (water/cellulose ratio of 3/1) and 102.5 F g -1 (water/cellulose ratio of 6/1). Additionally, it is noted that electrodes produced from the samples treated during 4 h have higher impedance at low operation frequency. The present study proves the possibility to substitute commercial activated carbons with cellulose-derived materials, the porosity of which can be tuned accordingly already during the pretreatment step.

Finland is a leading country on European wood pellet markets. Wood pellet production volumes in the country have increased steadily during the last decades. The aim of this paper is to present an overview of the current status of the Finnish wood pellet business. The paper identifies the main pellet producers by region and volume and describes domestic demand for wood pellets. The paper is based on a review of published scientific literature, latest Finnish official documents and country reports. The paper contributes to greater understanding of the Finnish pellet business., Proceedings of the 23rd European Biomass Conference and Exhibition, 1-4 June 2015, Vienna, Austria, pp. 1475-1480

Renewable energy (mainly hydroelectric power plants) has a significant share in energy generation sector in Brazil. Recent climate changes, however, resulted in lower rainfall indexes and acted as a driving factor for the increasing interest in biomass applications. Therefore, having the land available for forest planting and a critical need for a new source of renewable energy, Brazil has the potential to further increase the energy generation from biomass. Due to the diverse nature of biomass materials, their properties range widely and exhibit different behaviors in thermal processes. To choose the most efficient way for production of energy, it is required to know the energy potential of the biomass samples. This study focuses on the physical-chemical characterization of nine lignocellulosic biomasses widely available in Brazil: five types of eucalyptus wood chips, sugarcane bagasse, elephant grass, bamboo, and coconut husk. Some characteristics regarded as important to thermochemical conversion are evaluated, such as: biomass chemical composition - polisacharides (glucans, xylans, galactans, mannans, arabinans), total uronic acids, acetyl groups, lignin, chloride, elementary analysis of the ash (Cu, Fe, Ca, Mn, Mg and K), silica and extractives, heating value, ultimate and proximate analyses. Moreover, the studied samples were investigated by thermogravimetric analysis (TG and DTG). The evaluation of these characteristics is important for understanding the processes of the thermochemical conversion of biomasses., Proceedings of the 23rd European Biomass Conference and Exhibition, 1-4 June 2015, Vienna, Austria, pp. 294-298

The Russian wood pellet business has expanded rapidly in the last decade. The first pellet production plant was built in 2003 and within ten years Russia has become an important exporter of pellets, mainly to the Nordic and Baltic area. The aim of this paper is to present an overview of the current status of Russian wood pellet exports. The paper identifies the main pellet suppliers by region and volume, and describes domestic demand for wood pellets. In addition to reviewing the current pellet market status in Russia, the paper addresses challenges facing the Russian wood pellet business, both domestically and in key export markets. The paper is based on a review of published scientific literature, the latest Russian official documents and reports, and the IEA Bioenergy Task 40, Global Wood Pellet Industry Market and Trade Study. Attempts have been made to reconcile the varying and conflicting data given in different Russian documentation sources, thus permitting a more accurate representation of the Russian pellet business, an important player in global pellet trade. Despite its importance, there is limited work available on the Russian pellet industry. Thus, this paper contributes to greater understanding of the Russian pellet business. Based on an up­to­date analysis of the market situation, challenges and opportunities are presented for future scenarios of Russian pellet exports. The study further demonstrates the important role that Russia plays in the global pellet market. This paper finds that although the Russian pellet business developed very rapidly during 2004­2009 the industry now faces considerable challenges. Due to an oligopolistic market structure and a lack of opportunities for small and medium­sized companies, it is expected that, despite its obvious potential, the Russian wood pellet industry may not develop significantly in the near future., Proceedings of the 22nd European Biomass Conference and Exhibition, 23-26 June 2014, Hamburg, Germany, pp. 1526-1534

Small­scale combined heat and power (CHP) generation is developing, especially for wood fuels. Many technological options are needed in the market. The purpose of this paper is to address important practical pre­conditions for the design of a small­scale bio­CHP plant. Also, the objective is to show the benefit for the plant manufacturers to build up co­operation networks to achieve the latest technological performance and highest economy. This networking applies as well with the energy entrepreneurs operating the plants. As an example, a test facility was developed to promote the externally­fired microturbine (EFMT) technology and collaboration between the parties. The aim of this research is to demonstrate the importance of controlling the whole production chain to optimize its operation quality. By developing the technology, services and their quality it is easier for this technology to penetrate in the market. This paper identifies relevant practical factors when optimizing small­scale heat­only and CHP operation. To learn from field experience, heating plant manufacturers and heating entrepreneurs were interviewed. Also, heating plant operation statistics were used. Thus, factors for functionality and productivity of small boiler plants were recognized. Utilizing the received information, different production scenarios were calculated. The fuel quality control, boiler adjustability and its correct sizing indicated important. Small­scale plants have to adapt to wide periodical changes in heat demand. Hence, the adjustability of boilers is important, differing significantly from large boilers. For small boilers, this causes great differences in their annual operating times. The developed test facility consists of a 300 kW wood chip furnace, a 40 kW EFMT with heat exchangers and a 200 kW water boiler. The microturbine is based on turbocharger technology with limited pressure ratio and turbine inlet temperature, causing low electric efficiency and power­to­heat ratio. However, economic feasibility is anticipated due to low cost structure., Proceedings of the 19th European Biomass Conference and Exhibition, 6-10 June 2011, Berlin, Germany, pp. 967-973

Deposit formation and corrosion of recovery boiler superheater tubes are known to be interrelated with boiler chemistry and the design, as well as the operation conditions in an extremely complex way. After a short review of typical superheater corrosion conditions in the past, a brief summary is given about the work on particulate formation and agglomeration in the flue gas path. Deposit formation mechanisms, deposition fluxes, transformation processes, deposit heat conductivity and heat transfer, as well as transport of deleterious species in the deposits is illuminated by model calculations. Corrosion processes and materials performance is discussed with reference to the results of materials exposures in industrial recovery boilers, and in laboratory corrosion tests. As a conclusion, current needs and likely future trends in the materials technology of superheaters of modern recovery boilers typically operating firing high solids liquors and with low sulphur emissions are summarised.

The aim of this study is to facilitate the development of international biomass market. The paper identifies and highlights main producers and consumers as well as exporters and importers of liquid and solid biofuels and its volumes. Solid and liquid biofuels that are under consideration were industrial roundwood, wood chips and particles, fuel wood, wood pellets, biodiesel and bio-ethanol. This work contributes to understanding the global market of energy biomass until 2015. The study further demonstrates that bioenergy global markets are increasing, for example large progress was done in wood pellets markets., Proceedings of the 25th European Biomass Conference and Exhibition, 12-15 June 2017, Stockholm, Sweden, pp. 1439-1448

Brazil has one of the world’s largest potential for renewable energy production. However, the share of forest biomass-derived thermal and electrical energy is still low. Currently, the country relies on hydropower plants for electricity supply and, after severe drought periods, the energy market is facing increasing prices and uncertainties. In addition, most of the coal and natural gas consumed are imported. Energy intensive processes commonly utilize low-grade coals and petcoke, resulting in high carbon emissions. In order to increase the amount of sustainable biomass in the Brazilian energy matrix, this paper analyses the potential of biomass combustion and gasification in the mineral industry. Various processes were considered, such as iron ore mining and agglomeration, iron and steelmaking, cement production and limestone processing. The current biomass utilization and future scenarios are presented, and the numbers are compared to the global overview and to Northern European countries., Proceedings of the 24th European Biomass Conference and Exhibition, 6-9 June 2016, Amsterdam, The Netherlands, pp. 204-213

Boiler feedwater pumps are among the most energy-intensive auxiliary parts in steam boiler plants. Maintaining high availability and reliability has traditionally dominated the optimal design of the boiler feedwater pumping system. The operation of thermal power plants under variable load, e.g. due to the introduction of intermittent renewable energy sources, imposes additional energy losses on the pumping systems. This study aims to establish an algorithm to optimize energy consumption, consequently, life cycle costs of the boiler pumping system under cyclic operation. A mathematical model is presented for the analysis and optimization of various boiler pumping systems, including single and multiple pumps in constant or variable speed. The results indicate considerable potential for energy savings up to 20% by the optimization of stage numbers, pump numbers in parallel, booster pump characteristics, and drive's speed.