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Fluidized bed combustion of biomass requires maintaining stable properties of the inert bed material, which plays a key role in heat transfer, temperature stabilization and uniform fuel distribution in circulating fluidized bed (CFB) boilers. During long-term operation, quartz sand, i.e., the most commonly used inert material, undergoes physical and chemical degradation processes such as attrition, sintering and coating with alkali-rich ash, leading to changes in particle size distribution (PSD), deterioration of fluidization quality, temperature non-uniformities and an increased risk of bed agglomeration. This study analyzes quality management strategies for inert bed materials in biomass-fired CFB systems, with particular emphasis on the influence of PSD on boiler hydrodynamics and thermal behavior. Based on industrial operating data, sieve analyses and CFD simulations performed under representative operating conditions, a recommended mean particle diameter range of approximately 150–200 μm is identified as critical for maintaining stable circulation and uniform temperature fields. Numerical results demonstrate that deviations toward coarser bed materials significantly reduce solids circulation, promote segregation in the lower furnace region and lead to local temperature increases, thereby increasing agglomeration risk. The study further discusses practical approaches to bed material monitoring, regeneration and make-up management in relation to biomass type and ash characteristics. The results confirm that systematic control of inert bed material quality is an essential prerequisite for reliable, efficient and low-emission operation of biomass-fired CFB boilers.

Efficient and cost-effective biomass logistics remain a significant challenge due to the dynamic and nonlinear nature of supply chains, as well as the scarcity of comprehensive data on this topic. As biomass plays an increasingly important role in sustainable energy systems, managing its complex supply chains efficiently is crucial. Traditional logistics methods often struggle with the dynamic, nonlinear, and data-scarce nature of biomass supply, especially when integrating local and international sources. To address these challenges, this study aims to develop an innovative modular artificial neural network (ANN)-based Biomass Delivery Management (BDM) model to optimize biomass procurement and supply for a fluidized bed combined heat and power (CHP) plant. The comprehensive model integrates technical, economic, and geographic parameters to enable supplier selection, optimize transport routes, and inform fuel blending strategies, representing a novel approach in biomass logistics. A case study based on operational data confirmed the model’s ability to identify cost-effective and quality-compliant biomass sources. Evaluated using empirical operational data from a Polish CHP plant, the ANN-based model demonstrated high predictive accuracy (MAE = 0.16, MSE = 0.02, R2 = 0.99) within the studied scope. The model effectively handled incomplete datasets typical of biomass markets, aiding in supplier selection decisions and representing a proof-of-concept for optimizing Central European biomass logistics. The model was capable of generalizing supplier recommendations based on input variables, including biomass type, unit price, and annual demand. The proposed framework supports both strategic and real-time logistics decisions, providing a robust tool for enhancing supply chain transparency, cost efficiency, and resilience in the renewable energy sector. Future research will focus on extending the dataset and developing hybrid models to strengthen supply chain stability and adaptability under varying market and regulatory conditions.

This article presents a study of the effect of metal particle and carbon nanotube additives on the thermal diffusivity of a silica-gel-based adsorption bed of an adsorption chiller. The structural properties of silica gel and carbon nanotubes were investigated using the volumetric method of low-pressure nitrogen adsorption. Thermal characteristic tests of the prepared mixtures based on a silica gel with 5 wt% and 15 wt% of aluminum, copper, or carbon nanotubes were carried out. The obtained results show that all the materials used as additives in blends in this study achieved higher thermal diffusivities in comparison with the thermal diffusivity of the parent silica gel. However, the best effect was observed for the mixture with 15 wt% aluminum.

The secondary structure of proteins in unheated and heated whey protein isolate dispersions and the surface tension of the solutions were investigated at different pH. Heating protein solutions at 80°C results in an increase of unordered structure. Nevertheless, the difference between the contents of unordered structure in the unheated and heated samples increases with increasing pH of the solution. At low protein concentrations the surface tension decreased with increasing protein concentration to about 5 mg/ml. For the heated solution, a similar trend was observed in the decrease in the surface tension with increasing concentrations of protein. In both cases, the curves depicting the surface tension as a function of protein concentration could be fitted to the exponential function with a negative exponent, but with the heated solutions lower values of surface tension were observed. Studies on the surface tension of whey protein isolate solutions prove that the unfolding of whey proteins, revealed by changes in the secondary structure, causes a decrease in the surface tension.

An innovative idea, shown in the paper constitutes in the use of the fluidized bed of sorbent, instead of the conventional, fixed-bed, commonly used in the adsorption chillers. Bed–to–wall heat transfer coefficients for fixed and fluidized beds of adsorbent are determined. Sorbent particles diameters and velocities of fluidizing gas are discussed in the study. The calculations confirmed, that the bed–to–wall heat transfer coefficient in the fluidized bed of adsorbent is muchhigher than that in a conventional bed.

Fermented beverages are well-known and characterised at many levels. Hence, consumers have increasingly shown interest in this particular category of goods over the past few years. The study presented herein outlines the methodology employed for producing fermented whey beverages, encompassing laboratory and technical-scale settings. These beverages are crafted using sweet and sour organic whey sourced from cows or goats, complemented with organic Kamchatka berry, blackcurrant, or apple juices. In this study, tests were carried out on physicochemical, rheological and sensory aspects of organic goat’s and cow’s fermented whey beverages. Comparing the pH levels of the laboratory-produced beverages to those manufactured on a technical scale revealed striking similarities, whereas variations were observed in titratable acidity between the two settings. Despite this, all fermented beverages exhibited a desirable low viscosity. Furthermore, sensory evaluations yielded positive results across the assessors. Utilising whey—whether from goats or cows—as the base for fermented beverages with enhanced health benefits represents a commendable effort towards repurposing products traditionally considered waste.

The aim of this study was to investigate the gelation process of binary mixes of pumpkin-seed and egg-white proteins. The substitution of pumpkin-seed proteins with egg-white proteins improved the rheological properties of the obtained gels, i.e., a higher storage modulus, lower tangent delta, and larger ultrasound viscosity and hardness. Gels with a larger egg-white protein content were more elastic and more resistant to breaking structure. A higher concentration of pumpkin-seed protein changed the gel microstructure to a rougher and more particulate one. The microstructure was less homogenous, with a tendency to break at the pumpkin/egg-white protein gel interface. The decrease in the intensity of the amide II band with an increase in the pumpkin-seed protein concentration showed that the secondary structure of this protein evolved more toward a linear amino acid chain compared with the egg-white protein, which could have an impact on the microstructure. The supplementation of pumpkin-seed proteins with egg-white proteins caused a decrease in water activity from 0.985 to 0.928, which had important implications for the microbiological stability of the obtained gels. Strong correlations were found between the water activity and rheological properties of the gels; an improvement of their rheological properties resulted in a decrease in water activity. The supplementation of pumpkin-seed proteins with egg-white proteins resulted in more homogenous gels with a stronger microstructure and better water binding.

Spelt wheat is one of the oldest wheats cultivated by humans. It is characterised by high nutritional values and is sought after by consumers. Additionally, it does not have high habitat and fertilisation requirements and is resistant to diseases. The aim of this study was to determine the effect of different levels of nitrogen fertilisation and the intensification of fungicide protection on the grain quality characteristics of spelt cv. ‘Rokosz’ grown under south-eastern Polish conditions. The present research showed that the intensification of fungicide crop protection and increasing the nitrogen dose from 70 to 130 kg ha−1 had a positive effect on the quality features of spelt grains. The highest protein, gluten and starch contents were found after four fungicide treatments. These parameters increased their values under the influence of fungicides. After the application of 130 kg ha−1, spelt wheat grain had the most favourable chemical composition, containing the most protein, gluten, soluble dietary fibre, insoluble dietary fibre and fat. It also had a positive effect on the Zeleny sedimentation index and the amino acid content of the grain. Due to the favourable response of the spelt cv. ‘Rokosz’ to intensified fungicide protection and nitrogen fertilisation, it should be recommended for cultivation in integrated technology.

This study investigated the impact of storage conditions of the ingredients for yogurt production on the rheological and physicochemical characteristics of the final fermented product. The novelty is the application of a special mix of milk protein concentrate and sodium caseinate for yogurt production. Separately exposing the protein mix powder and bacteria culture to 20 °C caused considerable changes in the obtained yogurt stiffness and the incubation times required to produce the gel due to a decrease in bacterial count. Minimal changes in bacteria viability were observed after storage at 5 °C. Lower temperature and shorter storage times increased yogurt firmness, viscosity, and storage modulus, resulting in a smoother and more viscous product. A linear correlation was found between yogurt firmness and water activity. Powders stored at lower temperatures and for shorter times produced yogurt with stronger texture and better water binding. Additionally, yogurt obtained from dry ingredients stored under these conditions required shorter incubation times. Storing the starter culture at 5 °C for at least 8 weeks had no significant effects on the physicochemical properties or incubation time requited to produce the final yogurt. This work highlights the importance of storage conditions of yogurt dry ingredients in maintaining the quality of the final product.

Purpose The purpose of this paper is to first present the key features of the fuzzy logic (FL) approach as a cost-effective technique in simulations of complex systems and then demonstrate the formulation and application of the method. Design/methodology/approach The FL approach is used as an alternative method of data handling, considering the complexity of analytical and numerical procedures and high costs of empirical experiments. The distance from gas distributor, the temperature and the voidage of the bed, flue gas velocity and the load of the boiler are the input parameters, whereas the overall heat transfer coefficient for the membrane walls constitutes the output. Five overlapping sigmoid and constant linguistic terms are used to describe the input and the output data, respectively. The Takagi–Sugeno inference engine and the weighted average defuzzification methods are applied to determine the fuzzy and crisp output value, respectively. Findings The performed FL model allows predicting the bed-to-wall heat transfer coefficient in a large-scale 670 t/h circulating fluidized bed (CFB) boiler. The local heat transfer coefficients evaluated using the developed model are in very good agreement with the data obtained in complementary investigations. Originality/value The performed model constitutes an easy-to-use and functional tool. The new approach can be helpful for further research on the bed-to-wall heat transfer coefficient in the CFB units.