High Solid Content Research Articles

Performance, interaction, and metabolic pathway of novel dry–wet anaerobic digestion for treating high-solid agricultural waste

Anaerobic digestion (AD) with high-solid content of agricultural waste often leads to the accumulation of volatile fatty acids (VFAs) due to the imbalance of the functions of hydrolytic acidification bacteria and methanogenic archaea. This study developed a novel dry–wet AD of high-solid content was developed to make acidogenic bacteria and methanogenic archaea having higher collaboration ability. The results showed that the dry–wet AD system achieved a dynamic balance and synergistic effect between hydrolytic acidification and the methane production process, which shortened the lag phase to a minimum of 1.21 days. Additionally, the system exhibited a highest volumetric biogas production rate of 1.76 L L−1 d−1 when CM:CS and the initial pH were 6:4, 8.0, respectively. The total VFA concentration reached a maximum of 4.69 g L−1 d−1 and acetic acid (HAc) and butyric acid (HBu) were dominant VFAs (88.75%–93.27%) in the leachate in hydrolytic acidification phase. Metagenomic analysis indicated Pseudomonadales, Clostridiales, Bacteroidales, Spirochaetales, and Methanosaeta were dominant microorganism in hydrolytic acidification phase and methanogenic phase, respectively. The gene abundance of key enzymes in the acetoclastic methanogenic pathway significantly exceeded that of the hydrotrophic methanogenic pathway. This study provides a novel AD technology and insights into the energy conversion of agricultural waste.

Optimizing a canola-gelatine-urea bio-adhesive: effects of crosslinker and incubation time on the bonding performance

The importance of creating eco-friendly and health-conscious materials has become paramount in striving to attain long-term development goals. For the past decades, constant efforts have been made to tackle the issue of formaldehyde release from wood-based panels which, to date, are still mainly produced from unsustainable synthetic adhesives. In the pursuit of sustainable and environmentally responsible adhesive solutions for the wood industry, sodium bisulfate, sodium bisulfite, and sodium nitrite were used under different heat treatment conditions as crosslinkers for canola protein-based bio-adhesive formulations. The developed adhesive formulations showed outstanding mechanical properties, with a viscosity below 4000 mPa/s despite the relatively high solid content, as well as excellent bonding performances. The one-layer particleboards bonded with the canola-based adhesive demonstrated outstanding mechanical properties, with the internal bonding and the bending strength values surpassing 0.60 N/mm2 and 10 N/mm2, respectively. Notably, the sodium nitrite-crosslinked variants exhibited significantly superior performance compared to the UF-bonded control boards. Longer incubation times generally improve bonding strength, with sodium nitrite showing the most pronounced effects. The results of this research showcase not only the possibility of developing a plant protein-based wood adhesive with high solid content, but also the potential superiority of canola protein-based wood adhesives when compared to conventional, synthetic counterparts. These findings offer valuable insights for optimizing bio-based adhesives in wood composite manufacturing, highlighting sodium nitrite as a promising crosslinker for enhancing the adhesive’s performance.

Nickel's behaviour in marine sediments under aerobic to anaerobic diagenetic conditions

In the marine environment, nickel distributions are linked to the biogeochemical cycling of both organic matter and manganese. Thus, Ni and its isotopes have the potential to be used to reconstruct changes of bioproductivity and oxygenation in paleoenvironments. However, their utility relies on an understanding of the behaviour of Ni in modern marine environments. Here we investigate the distribution of Ni under a range of oxidation-reduction conditions, with organic carbon (Corg) burial rates that range from approximately 0.08 to 8.4 mmol m−2 d−1, none of the sites show deep (> 5 cm) penetration of dissolved oxygen into the sediment. We present Ni concentrations for sediments and pore fluids, as well as Ni isotope compositions from pore fluids, from the California and Mexico continental margins. The sites are sufficiently reducing that solid-phase Mn concentrations are typically <1000 ppm, but two of the stations, where oxygenated bottom water bathes the underlying sediment, have near-surface sediment Mn concentrations that reach up to 2.3%.Dissolved Ni is lower in pore fluids for stations with high solid phase Corg compared to those stations with oxygenated bottom water and high solid phase Mn concentrations. The calculated benthic fluxes of Ni at all stations are small relative to their burial rates, which implies a high Ni burial efficiency (> 85%). Pore fluid δ60Ni values range from approximately −0.39 to +2.36 ‰, with the higher δ60Ni values occurring at the Corg-rich station, and the lower values at the Mn-rich stations. At the station with the highest Corg content, the distribution of solid-phase Ni as a function of Corg content is consistent with the strong association of Ni with Corg seen at open-ocean upwelling margins globally. In contrast, the other stations investigated here clearly do not show such an association. Our data offer support for the notion that Ni accumulation within sediments is linked to organic matter accumulation in regions of high photic zone productivity and where the sediments are reducing. However, at the sites in our study where Mn oxidation-reduction reactions occur near the sediment-water boundary, any simple relationship between Ni and Corg burial is obfuscated. With a sufficiently deep oxygen penetration depth and the formation of a solid-phase Mn oxide layer, Ni burial within the sediment can be highly efficient. Importantly, Ni is well preserved in sediments deposited under the full range of conditions studied here. This observation of high Ni preservation is an important constraint if Ni is to be used as a proxy to reconstruct paleoenvironmental conditions.

Solventless recovery of lipids from urban sewage sludge: How to sustainably turn a waste into a valuable source of oleochemicals

For the first time, the recovery of lipids from urban sewage sludge was investigated through a solvent-free process based on elementary operations validated on a pilot scale (2 tons per hour). Sedimented sewage sludge was dewatered through centrifugation, acidified (and in the case treated with hydrogen peroxide), heated to 80 °C and centrifuged to obtain three different streams: i) raw grease, ii) exhausted aqueous phase, and iii) dewatered sludge.The recovery yield of grease from sludge could reach a very high value (70 wt%), depending essentially on the initial lipid content in sewage sludge, which was monitored and found to range between 1.1 and 6.6 wt% (13–25 wt% with respect to TS). The use of H2O2 played a crucial role in the recoverability of lipids and the relevant pureness in free fatty acids content (>89 wt%). In addition, the total solids content in the exhausted aqueous phase and the final residual sludge were sensibly affected by using H2O2. Final dewatered sludge had a very high content of solids (TS 31.0 ± 2.3 wt%) and resulted in 15 % less of the amount of sludge conventionally obtained from anaerobic digestion. According to these figures, for medium wastewater treatment plants, a selling price of 800–900 Euro per ton of grease would guarantee a return on investments within three years of operations. This simple procedure represents a quick and proficient way to treat sewage sludge, turning it into a valuable feedstock for fine chemicals, in agreement with Circular Bioeconomy principles.

High PZT-power actuation for the separation of polydisperse glycine crystals at high flow rates and solid content using acoustophoresis

Acoustofluidics is a technique that can be used for particle separation purposes in both chemical and biological fields, with the technique appreciated for its capability of handling delicate material with no need for functionalization of particles/cells. Due to the generation of heat during the actuation of a ceramic piezoelectric element (PZT) and due to clogging, acoustofluidic separation is currently limited to dilute suspensions at a low flow rate. PZT actuation at a frequency that induces an acoustic standing wave drives the migration of particles toward the center of the channel. To overcome heating due to actuation at high power, a Peltier-based cooling system maintains the temperature of the PZT to a set point, keeping stable performance for up to a tested time of 24 min. Separation of suspensions of 10 wt.% and 5 wt.% of polydisperse glycine crystals in 5 v% methanol – ethanol buffer was achieved at a flow rate of 0.2 L/h. The cut-off found for the separation was 29.24±1.87μm and 19.51±1.19μm for 5 wt.% and 10 wt.%, respectively.

GGE analysis and stability of traits in tomato cultivars grown under organic farming conditions: A two-year study

The increasing conversion of agricultural land to organic farming requires the development of specifically adapted cultivars. So far, in tomato there is lack of research for selection of germplasm suitable for sustainable agroecosystems. In this study, we investigated the genotypic and environmental factors affecting the variation of plant, fruits, and root traits in 39 tomato genotypes grown under organic farming conditions. Four independent experiments were conducted in Italy and Spain across two consecutive seasons in 2019 and 2020. For all traits, the factorial linear regression model to estimate the main effects of genotype (G), location (L), year of cultivation (Y) and their interactions, revealed highly significant (P < 0.001) variations, with the G factor being largely predominant for most traits. The implementation of the “which-won-where”, “mean performance versus stability” and “discriminative vs representativeness” patterns in the GGE (Genotype plus Genotype by Environment interaction) analysis, allowed the identification of superior cultivars with high stability across the testing environments. Genomic characterization with 30 890 high quality SNPs from ddRADseq genotyping analysis, revealed that a specific cluster of cherry tomato accessions were low performing in terms of yield and fruit weight, on the contrary, showed a high content of soluble solids, which in agreement with GGE analysis. Results of this study provide a framework for the potential use of this locally adapted tomato germplasm to address the needs of more sustainable agriculture.

Determination of the region‐specific characteristics of traditional Korean doenjang produced in Chungcheongbuk‐do through physicochemical property, enzyme activity, and descriptive sensory analyses

AbstractThis study determined the region‐specific characteristics of traditional doenjang produced in Chungcheongbuk‐do by analyzing the physicochemical properties, enzyme activities, and aroma characteristics of the samples. Color, moisture, pH, soluble solid content, salinity, acid value, titratable acidity, amylase and protease activities, and NH2‐N, alcohol, and total/reducing sugar contents were analyzed. A descriptive sensory analysis involving trained sensory panelists was also conducted for aroma profile determination. Similarities were observed among the samples produced in the same city. The Yeongdong‐made samples had strong fermented and lipid/musty aromas. The Cheongju‐made doenjang had a high protease activity and a high NH2‐N content. The Goesan‐made samples had a high reducing sugar content due to amylase activities and a fishy aroma, and the Jincheon‐made doenjang had a high soluble solid content and an intense spice aroma. This study describes for the first time the region‐specific characteristics of traditional doenjang produced in Chungcheongbuk‐do.Practical applicationsTraditional food produced through a natural fermentation process may have differences in physicochemical properties and flavor due to the diversity of microbial communities depending on the region and environment. Previous studies have identified the characteristics of traditional Korean fermented foods such as doenjang and kimchi in each region, but this study is the first to analyze differences in the characteristics of traditional doenjang produced in a small city within a specific region (Chungcheongbuk‐do). The findings from this study can give baseline information on the doenjang produced by small‐ to mid‐sized doenjang manufacturers located in Chungcheongbuk‐do, and allow them to use it for strategic marketing to expand their market to the national market in Korea.

Enhancement of Biodegradability of Chicken Manure via the Addition of Zeolite in a Two-Stage Dry Anaerobic Digestion Configuration.

Leach bed reactors (LBRs) are dry anaerobic systems that can handle feedstocks with high solid content, like chicken manure, with minimal water addition. In this study, the chicken manure was mixed with zeolite, a novel addition, and packed in the LBR to improve biogas production. The resulting leachate was then processed in a continuous stirred tank reactor (CSTR), where most of the methane was produced. The supernatant of the CSTR was returned to the LBR. The batch mode operation of the LBR led to a varying methane production rate (MPR) with a peak in the beginning of each batch cycle when the leachate was rich in organic matter. Comparing the MPR in both systems, the peaks in the zeolite system were higher and more acute than in the control system, which was under stress, as indicated by the acetate accumulation at 2328 mg L-1. Moreover, the presence of zeolite in the LBR played a crucial role, increasing the overall methane yield from 0.142 (control experiment) to 0.171 NL CH4 per g of volatile solids of chicken manure entering the system at a solid retention time of 14 d. Zeolite also improved the stability of the system. The ammonia concentration increased gradually due to the little water entering the system and reached 3220 mg L-1 (control system) and 2730 mg L-1 (zeolite system) at the end of the experiment. It seems that zeolite favored the accumulation of the ammonia at a lower rate (14.0 mg L-1 d-1) compared to the control experiment (17.3 mg L-1 d-1). The microbial analysis of the CSTR fed on the leachate from the LBR amended with zeolite showed a higher relative abundance of Methanosaeta (83.6%) compared to the control experiment (69.1%). Both CSTRs established significantly different bacterial profiles from the inoculum after 120 days of operation (p < 0.05). Regarding the archaeal communities, there were no significant statistical differences between the CSTRs and the inoculum (p > 0.05).

Systematic underestimation of polycyclic aromatic hydrocarbon aqueous concentrations in rivers

Polycyclic aromatic hydrocarbons (PAHs) are a widespread group of organic contaminants whose presence in water bodies is cause of severe concern. With few exceptions, the majority of PAHs is hydrophobic, presents a high adsorption affinity, and is thus primarily transported within river systems during high-flow events together with suspended particulate matter (SPM). Evidence exists of analytical challenges related to the incomplete extraction of PAHs adsorbed to solids and thus to a potential negative bias in the chemical analysis of PAHs in bulk water samples with high SPM content. Despite this, partly due to the elevated efforts required to collect representative samples containing sufficient SPM for the separate PAH analysis in this matrix, several investigations rely on the analysis of aqueous samples. This study tests the hypothesis that surveys based exclusively on bulk water may lead to a systematic underestimation of the real contamination level and transport of PAHs in rivers. Six high-turbidity events were examined in three Austrian rivers applying time-integrated sampling and simultaneously analyzing PAHs in total bulk water, filtered water, SPM, and supernatant. Despite an unavoidable degree of uncertainty in such challenging sampling scheme, the results indicate that measurements performed with best available standard methods in bulk water samples determined in average only about 40% of the theoretically expected total PAHs concentrations derived from the analyses in SPM. Such deviation has important implications for the reliable assessment of the compliance with environmental quality standards as well as for surveys aimed to estimate riverine loads, validate emission models, and understand the transport dynamics of PAHs in rivers. Whereas the first objective, e.g., in European countries, is alternatively achieved via monitoring in biota, the latter ones require efforts directed to complement monitoring campaigns with separate sampling of SPM, with monitoring of suspended solids transport to appropriately select and interpret the results of water samples and to improve the chemical analysis of PAHs in bulk water samples with high solids content.

Research on Ternary Composite Flooding Produced Water Treatment Process

This paper introduces the ternary composite drive technology and the characteristics of the technology. The characteristics of ternary composite flooding produced water were sorted out, and the characteristics of complex organic composition, poor biochemical treatment, high oil content, high suspended solids content, high viscosity and high emulsification degree were sorted out. Three ternary composite flooding produced water treatment processes were introduced. Under the condition of ensuring that the effluent meets the requirements of reinjection water, the advantages and disadvantages of the three processes are compared, and finally the third process flow is determined to be the optimal option. The process can not only effectively improve the treatment effect of ternary composite flooding produced water, but also overcome the shortcomings in the conventional process, improve the feasibility of the process and reduce the cost.

Fabrication of Y2O3–CaO composite ceramics with controllable hydration resistance by a novel gel casting method

Y2O3 and CaO are ideal ceramic materials for precision casting of TiAl alloy, overcoming challenges associated with intricate component removal, such as turbine blades, leveraging the stability of Y2O3 and the water solubility of CaO. To address these challenges, we employed Isobam104 in a novel gel casting method, serving as both a dispersant and a gelling agent. This method enabled us to create a stable Y2O3–CaCO3 slurry with high solid content (up to 55 vol%) and low viscosity (101.51 mPa·s at a shear rate of 10 s−1). Following sintering at 1500 °C for 2 h, Y2O3–CaO composite ceramics were produced. Surprisingly, two distinct characteristics of CaO were noted. One showed a rod-shaped morphology with high chemical reactivity crucial for water solubility, while the other displayed a flat-like feature, forming a well-maintained interface due to its coherent or semi-coherent matching relationship with Y2O3, thereby providing excellent hydration resistance. Ultimately, we acquired composite ceramics showcasing a 30-day “shelf life" alongside exceptional water solubility. This establishes the theoretical groundwork for storing and employing soluble ceramic cores in the precision casting of TiAl alloy.

Exogenous Methyl Jasmonate (MeJA) Improves 'Ruixue' Apple Fruit Quality by Regulating Cell Wall Metabolism.

'Ruixue' apples were used as the test material to study the effect of 10 μM methyl jasmonate (MeJA) on the quality and cell wall metabolism of apples after 18 d of storage. The results showed that MeJA significantly decreased the respiratory rate, reduced the titratable acid content and maintained a high soluble solids content. MeJA has been shown to suppress the activities and gene expressions of WSP, CSP, ISP, and cellulose in contrast to the control group, thereby maintaining a lower cell permeability and higher exocarp firmness. MeJA significantly decreased the expression of MdACS, MdACO, MdPL, Mdgal, and MdPG genes in the apple exocarp when compared to the control group. In addition, the overexpression of MdPL18 increased the content of cell wall polysaccharides such as WSP and CSP, enhanced cell wall-degrading enzyme activities, and accelerated fruit ripening and softening, whereas silencing MdPL18 did the opposite. Together, these results demonstrate that exogenous MeJA maintains the Ruixue apple fruit quality by regulating the metabolism of cell wall substances.

In-line image analysis of particulate processes with deep learning: Optimizing training data generation via copy-paste augmentation

Monitoring particle properties directly in the process using in-situ microscopes can provide valuable input for control loops, improve process understanding, and facilitate process optimization. However, obtaining reliable information from these images is still challenging, particularly for higher solids concentrations or agglomerating systems. Recent studies have successfully applied deep learning models to extract particle characteristics from in-situ image data. Despite these advances, the problem of generating training data has not been properly addressed. Manual annotation is time-consuming and prone to bias due to high particle counts, particle overlap, and out-of-focus objects. This paper introduces a new approach to generating training data for segmentation models by combining conventional segmentation methods with copy-paste augmentation. A case study was conducted in which depth filtration experiments were performed using irregularly shaped alumina particles. An instance segmentation model trained on data created with the proposed approach successfully detected and characterized particles, even at high solids concentrations.

Combining pre-fermentation and microbial electrolysis for efficient hydrogen production from food wastewater

Energy-rich food wastewater (FWW) offers a sustainable feedstock for bioelectrochemical hydrogen production. However, its complex characteristics and high suspended solids content hinder its direct utilization in dual-chamber microbial electrolysis cells (MECs) for producing high-purity hydrogen. This study explored pre-fermentation under uncontrolled pH conditions as a method to improve the exoelectrogenic utilization of FWW in dual-chamber MECs. Across 2–5 d hydraulic retention times (HRTs), pre-fermentation was effective in conditioning FWW to a more favorable composition for exoelectrogenic utilization. Short-chain organic acids and ethanol constituted 48–72% of the total chemical oxygen demand (COD) in pre-fermentation effluents, a substantial increase from 27% in raw FWW. In subsequent MEC experiments, the MECs fed with pre-fermentation effluents exhibited significantly higher current-generating and hydrogen-producing performance compared to those fed with raw FWW. The MECs fed with the 2-d HRT pre-fermentation effluent showed the highest hydrogen yield of 911 mL/g COD fed, which represents a 34.4% increase compared to the MECs fed with raw FWW, resulting in a 1.28-fold higher recovery of chemical energy from organic matter in raw FWW as hydrogen. The anode bacterial community was dominated by exoelectrogenic Geobacter in all MECs, with its abundance being significantly higher when utilizing pre-fermentation effluents (69.0–78.0%) compared to raw FWW (20.6–39.2%). Overall, pre-fermentation proved an effective conditioning approach for enhancing the exoelectrogenic utilization of FWW in MECs.

A novel chitosan and polyferric sulfate composite coagulant for biogas slurry pretreatment by simultaneous flocculation and floatation: Performance and underlying mechanisms

Biogas slurry from anaerobic digestion is rich in nutrients but has not been fully utilized due to a high content of suspended solids (SS) causing clogging during agricultural irrigation. This study aimed to evaluate the performance of a novel chitosan and polyferric sulfate (CTS-PFS) composite coagulant for simultaneous flocculation and floatation to enhance SS removal while preserving nutrients in biogas slurry. Orthogonal method was used for experimental design to determine the optimal synthesis and operational conditions of CTS-PFS. Results show that CTS-PFS outperformed individual CTS and PFS coagulant in terms of SS removal and nutrient (nitrogen, phosphorus, and potassium) preservation. Compared to individual CTS and PFS coagulation, the combination of CTS and PFS at the mass ratio of 1:6 showed significantly higher performance by 41.5 % increase in SS removal and 5.2 % reduction in nutrient loss. The improved performance of CTS-PFS was attributed to its formation of polynuclear hydroxyl complexes with ferric oxide groups (e.g. Fe-OH, Fe-O-Fe, Fe-OH-Fe and COO-Fe) to strengthen charge neutralization and adsorption bridging. Data from this study further confirm that CTS-PFS enhanced the removal of small suspended particles and dissolved organic matter in the molecular weight range of 0.4–2.0 kDa and preserved ammonia and potassium better in biogas slurry. Bubbles were generated as hydrogen ions from coagulant hydrolysis interacted with bicarbonate and carbonate in biogas slurry for removing the produced flocs by floatation. Floc flotation was more effective in CTS-PFS coagulation due to the significant production of uniform bubbles, evidenced by the reduction in the viscosity of biogas slurry.

High stability, high solid content, low viscosity titanium dioxide dispersion

High stability, high solid content, low viscosity titanium dioxide dispersion

Additive manufacturing of synthetic rubber ink with high solid content reinforced by networked silica

Abstract Silica is a reinforcing filler commonly used in the production of environmentally friendly tires, as tires reinforced with silica have lower rolling resistance, which translates into reduced energy consumption and improved fuel economy. However, achieving the optimal dispersion of silica within the rubber matrix is crucial for maximizing its reinforcing effects. In this study, a three- dimensionally networked silica (NS) was introduced in various amounts to rubber inks to improve their tensile strength and increase miscibility to enable their use in additive manufacturing. The results show that synthetic rubber ink with a high content of styrene–butadiene rubber (90%) and reinforced by NS possesses adequate viscosity for use in the direct ink write (DIW) process. NS was confirmed to have an impact on the rheological properties and printability of the rubber ink as well as to improve the tensile strength of the printed parts. Different formulations were tested to study and facilitate the vulcanization process and identify the optimal curing conditions as well as the print parameters to use in DIW printing. The successful printing and vulcanization of various printed structures demonstrates the potential for using the developed printable ink in additive manufacturing. This study opens up new possibilities for creating rubber products (such as tire treads) with adequate flexibility and high tensile strength.

Regulation of fat crystals in water-in-oil emulsions by high-intensity ultrasound: Crystal size and tracing of droplet distribution

In this paper, two emulsion systems with high and low solid fat contents were prepared from 20 % water phase and 80 % oil phase by adjusting the palm oil/palm stearin/soybean oil ratio. Different ultrasonic power and time were used for the pretreatment of emulsion with different solid fat content, and the application characteristics of ultrasonic in W/O emulsions were explored and evaluated. Directly using high-intensity ultrasound to prepare fatty emulsions would weaken the hardness and storage modulus G' of the samples. Although ultrasound reduced the size of fat crystals in emulsions, the interaction between water droplets and fat crystals needs to be considered. After ultrasonic treatment, water droplets were difficult to immobilize on the crystal surface and thus acted as an active filler to stabilize the emulsion together with the fat crystal network. In high solid fat emulsion systems, an increase in ultrasound power (from 100 W to 200 W) could more affect the crystallization behavior of fats than an increase in ultrasound duration (from 30 s to 60 s), and the distribution of crystals and droplets was more uniform. In the low solid fat emulsion system, the texture of the sample after ultrasonic treatment was softer, and the surface was more delicate and smoother. However, the higher ultrasonic intensity (200 W) was not conducive to the preparation of the spread. Although the ultrasound with excessive intensity promoted the formation of small crystals, it would also lead to the aggregation of small crystals. These small crystals cannot form a uniform crystal network, which increases the fluidity of emulsions.

Different effects of pea protein on the properties and structures of starch gel at low and high solid concentrations

In the context of starch–protein composite gels, the influence of protein on gel formation significantly shapes the textural attributes of starch gels, leading to distinct outcomes. This study aimed to evaluate how different ratios of pea protein (PP) affect the properties and structures of starch–protein composite gels at low (10 wt%) and high (40 wt%) solid concentrations. The addition of PP had opposite effects on the two gels. Compared to the pure starch gel, the low-concentration composite gel (LCG) with 20 % PP experienced a 48.90 ± 0.33 % reduction in hardness, and the storage modulus (G′) decreased from 14,100 Pa to 5250 Pa, indicating a softening effect of PP on LCG. Conversely, the hardness of the high-concentration composite gel (HCG) with 20 % PP exhibited a 62.19 ± 0.03 % increase in hardness, and G′ increased from 12,100 Pa to 41,700 Pa, highlighting the enhancing effect of PP on HCG. SEM and fluorescence microscopy images showed that PP induced uneven network sizes in LCG, while HCG with a PP content of 20 %, PP, together with starch, formed a three-dimensional network. This study provides valuable insights and guidance for the design and production of protein-enriched starch gel products with different textural properties.

Investigation on drawdown process of light-floating particles in a pilot scale cup-shaped blade agitator

The novel cup-shaped blade agitator with pilot scale was successfully applied in light-floating particles drawdown dispersion under high solid content (40 vt.%) for the first time. The drawdown dispersion effect of cup-shaped blade agitator was systematically investigated, by integrating the CFD simulation, the research unveils the impact mechanisms of flow conditions within the agitator on particle drawdown and dispersion, under various structural and operational parameters of the cup-shaped blade (CB) impeller. The optimum structure for CB was determined as CB2, with impeller deflection angle of -30°, and impeller diameter of 0.43 m. Under this structure, the CB agitator exhibits the best performance and can complete drawdown dispersion of light-floating particles at high solid concentration exceeding 40 vt.%. Besides, at lower solid particle volume concentration (Cv), both Njd and Pjd increase with increasing Cv. Interestingly, after Cv exceeds 10%, Njd and Pjd decrease as Cv continues to rise. Comparing with traditional impeller RT and PBT, the CB impeller is more competitive. Finally, dimensionless correlations of Njd and Pjd were established to provide practical guidance for application and optimization of CB agitator.