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The increasing share of renewable energy sources in power grids demands greater load flexibility from thermal power plants. Circulating Fluidized Bed (CFB) combustion systems, while offering fuel flexibility and high thermal inertia, face challenges in maintaining hydrodynamic and thermal stability during load transitions. This study investigates partial flue gas recirculation (FGR) as a strategy to enhance short-term load flexibility in a 1 MWth CFB pilot plant fired exclusively with solid recovered fuel. Two experimental test series were conducted. Under conventional operation, where fuel and fluidization air are reduced proportionally, load reductions to 86% and 80% led to operating regime shift. Particle entrainment from the riser to the freeboard and loop seal decreased, circulation weakened, and the temperature difference between bed and freeboard zone increased by 71 K. Grace diagram analysis confirmed that the system approached the boundary of the circulating regime. In contrast, the partial FGR strategy maintained total fluidization rates by replacing part of the combustion air with recirculated flue gas. This stabilized pressure conditions, sustained particle circulation, and limited the increase in the temperature difference to just 7 K. Heat extraction in the freeboard remained constant or improved, despite slightly lower flue gas temperatures. While partial FGR introduces a minor efficiency loss due to the reheating of recirculated gases, it significantly enhances combustion stability and enables low-load operation without compromising fluidization quality. These findings demonstrate the potential of partial FGR as a control strategy for flexible, waste-fueled CFB systems and supports its application in future low-carbon energy systems.

Over the past two decades, the technology underlying Hybrid Ocean Thermal Energy Conversion (H-OTEC) power plants have progressively matured. These advancements position H-OTEC as a promising alternative energy source with significant potential to replace traditional power plants. The cold discharge from H-OTEC Pilot Plants reduces the temperature of receiving water bodies, thereby directly or indirectly impacting the marine ecological environment. A one-year study was conducted around a pilot-stage 1.0 MW H-OTEC Pilot Plant in Port Dickson to investigate the effects of cold discharge on macro- and meiobenthic communities across different seasons. Apart from the water temperature within a 5-meter range affected by the H-OTEC cold discharge, the impact on other water quality indicators is negligible. A total of 22 macrobenthic species belonging to 4 phyla and meiobenthic organisms belonging to 9 taxa were identified across 15 sampling points. This study demonstrated that cold emissions had a limited impact on the abundance and community structure of benthic organisms across different seasons. The abundance of benthic organisms exhibited a significant increase in Inter-monsoon, followed by a significant decrease in Dry season. Moreover, there was a positive correlation observed between the abundance of benthic organisms and the content of water temperature, conductivity, gavel, sediment pigments and total organic matter. This study identified significant seasonal variations in the structure of both macro- and meio-benthic communities. Specifically, Umbonium vestiarium and other gastropoda were the dominant taxa and primary contributors to the observed significant changes in the structure of macro- and meio-benthic communities, respectively. Nevertheless, further study with a higher discharge volume of the outfall is crucial to assist in the outfall pipe placement of the mega-scale OTEC electricity plant. This study provided crucial insights into the ecological impacts of cold emissions from H-OTEC Pilot Plants in tropical coastal areas.

Increasing the recovery in electrodialysis desalination may be achieved using a single-pass operation at different linear flow velocity values in the diluate and concentrate compartments. The risk of inner leakage as well as membrane bulging and damage can be minimized by controlling the pressure difference between the diluate and concentrate compartments. This solution has been tested in a pilot plant for initial demineralization of river water using an electrodialyzer of our own design. Both under- and overlimiting regimes have been tested, as well as long work cycles between electrode polarity reversals. Water with a conductivity of about 500 µS/cm was desalinated at a recovery of 70–75%, and the desalination degree was 75–96%. It was also found that the unit cost could be decreased by 52% compared to a commercial solution when the diluate conductivity was 74.3 μS/cm. A deep demineralization, from 511 μS/cm down to 17.9 μS/cm in a single-stage EDR or 8.52 μS/cm in a two-stage EDR, was also confirmed experimentally at the pilot scale.

The technical training associated with urban water cycle management has a markedly multidisciplinary character. In Spain, training in this field to cover the different professional profiles involved in urban water management ranges from specific intermediate and higher Vocational Education and Training Programmes to related subjects included in various university degrees, as well as specialised master’s degrees in a very specific discipline involved in water management. Paradoxically, the companies in the sector are finding it difficult to find intermediate and higher technicians with training in line with their current needs to meet the challenges they must face in order to manage the sewerage and supply networks as efficiently as possible. It is necessary to incorporate, in Vocational Education centres, innovative methods and means that facilitate the acquisition of the skills required by key sectors for sustainability, such as urban water management. The incorporation of resources that help students to understand complex concepts in this field through the operation of pilot-scale equipment and installations that simulate those they will encounter in their professional performance can be of great value in facilitating the acquisition of the desired competences. In this work, a bibliographical review of the use of pilot plants for teaching purposes, in relation to technical aspects involved in the field of urban water management circumscribed to urban supply and sanitation networks, is carried out in order to assess the degree of their implementation as a training resource, which aspects are most frequently addressed, and the contribution they make to the improvement of teaching–learning processes.

Ultrafiltration (UF) is increasingly used in the food industry and for wastewater treatment and water reuse. Knowledge of the membrane properties that stabilise during the initial period of module operation in an industrial plant is essential for design purposes. This paper presents the experimental tests carried out using a pilot plant with an industrial PCI B1 membrane module. The module was equipped with tubular FP100 (100 kDa) polyvinylidene fluoride (PVDF) membranes used to separate carwash wastewater. The effect of membrane compaction during the first few days of the process on changes in permeate flux and dextran (40–500 kDa) separation rate was investigated. The effect of fouling, membrane washing with P3 Ultrasill 11 solution (pH = 12) and maintenance with sodium metabisulfite solution on the stabilisation of the technological performance of the plant was determined.

The performance of a Mayenite-supported nickel-based catalyst were investigated by using an in-house-designed, assembled and set-up chemical pilot plant, which was developed to provide experimental insights relevant to industrial scale up. In particular, the proposed heterogeneous catalytic system was structured in mm-sized spheres and tested in a large-scale experiment, in a fixed-bed reactor for the CO2 methanation process, and the results were compared with the output achieved with a Ni/alumina catalyst produced by an analogous route as the benchmark. The obtained findings highlighted the effective potential of the Mayenite structure supporting metallic active sites in promoting CO2 reduction under the selected operating conditions (450 °C, 4 bar), along with long-term stability and high CH4 selectivity. Moreover, the available experimental equipment was optimized to achieve accurate estimations of amounts of reaction by-product, as confirmed by the optimal agreement with the mass balance retrieved from the measured gaseous outlet composition. Such an achievement, notable for a large-scale chemical plant, plays a capital role in terms of industrial applications due to the critical impact of residual carbon and water in establishing the viability of innovative catalyst systems for the CO2 recycling process.

Tungsten is a critical raw material with increasingly important industrial applications. It is primarily found in minerals such as scheelite and wolframite (0.5% W), which are extracted and processed at the mine site to produce a high-grade scheelite concentrate (60% W). This process results in significant tungsten losses in the form of tailings, currently not utilized at the EU level. Deep eutectic solvents and imidazolium-based ionic liquids have been shown to possess excellent utility for recovering tungsten from low-grade concentrates, achieving tungsten oxide (96% purity) at high global yields (80%). In this study, an optimized ionic liquid-based process (involving leaching, solvent extraction, crystallization, and calcination) was developed at the laboratory scale. Important issues such as solvent flammability or the commercial availability of ionic liquids were addressed to ensure the safety and industrial feasibility of the process. Furthermore, a pilot plant was designed, constructed, and operated for a significant period (3 days). Tungsten oxide was produced with improved purity (>99%) and global yield (91.6%) in continuous operation.

This study aims to improve the economic efficiency of the pitch synthesis reaction on the pilot plant by optimizing the pitch synthesis reaction and utilization of the byproduct. The pitch was synthesized using a 150 L pilot plant with pyrolyzed fuel oil as a precursor. The pitch synthesis reaction is carried out through volatilization and polycondensation, which occur at 300 and 400 °C. Volatilization is terminated during heating; thus, additional soaking time is meaningless and reduces the process efficiency. Soaking time is a major variable when the synthesis temperature exceeds 400 °C. The byproduct is generated through volatilization; thus, its chemical characteristics are only influenced by the reaction temperature. The byproduct consists of various polycyclic aromatic hydrocarbons. The average molecular weight and yield of the byproduct increase with the reaction temperature. Carbon black was synthesized using chemical vapor deposition from the byproduct. The particle size of carbon black was controlled by the used precursor (byproduct), and the electrical conductivity of prepared carbon black has a maximum of 58.0 S/cm. Therefore, carbon black, which is synthesized from the byproduct of pitch synthesis, is expected to be used as a precursor for conductive material used in lithium-ion batteries or supercapacitors.

The influence of pulping variables on the pulp and black liquor properties for a neutral sulphite semi-chemical pulping system was investigated in a pilot plant pulping setup situated at an industrial paper mill. Eucalyptus chips were used as raw material and the operating variables were Na2SO3 charge (8–18% w/w on oven-dry wood), Na2CO3 charge (0.5–3.0% w/w on oven-dry wood) and maximum cooking temperature (160–180 °C). Response surface methodology was used to parametrize empirical models to find the optimal conditions for maximizing the short-span compression strength index of the pulp. The derived regression models for the black liquor properties and the pulp hypo number had R2-adjusted values above 0.8 and p-values for overall significance below 0.05. The derived regression models for the handsheet strength properties had R2-adjusted values between 0.3 and 0.45 and p-values for overall significance either below 0.05 or between 0.05 and 0.1. The sulphite charge, followed by the carbonate charge, had the most notable effect on the evaluated properties with the effects of temperature being less significant. Optimization of the pilot plant system showed that the short-span compression strength index of the pulp could be maximized to 26.7 N m/g, using a sulphite charge of 9.4% (w/w on oven-dry wood) and a carbonate charge of 1.94% (w/w on oven-dry wood), similar to short-span compression strength indices typically achieved using other pulping processes.

Biological filtration is a process that can be used for ammonium removal from water. The removal of ammonium is based on the nitrification process. Nitrification depends on many factors, such as water quality and filtration process parameters. To investigate the influence of filtration rate on the nitrification efficiency, nitrifying biofilters were formed at the pilot plant in the industry for drinking water production from surface water. The new biological filters were started under optimal conditions for biofilm formation. After the biofilm formation, the influence of the filtration rate on nitrification was examined over 3 months (from November to January). The time required for the spontaneous growth of nitrifying bacteria on the new filters was around 70 days. The operating conditions at the start-up period were the continuous flow of water containing γ(NH4+) ≈ 1mg/L, dissolved oxygen in a concentration >9 mg/L, filtration rate <1 m/h, inlet water temperature >12 °C and pH from 7.8 to 8. After the complete formation of the nitrifying biofilm, the percentage of NH4+ removal was greater than 95% for all tested filtration rates, from 0.5 to 8.4 m/h, at γ(NH4+) from 1 to 2.5 mg/L and raw water temperature from 13 to 7°C.