Search Results (7)

Cheese powder is a product resulting from the removal of moisture from cheese. At first, cheese emulsion is prepared by dissolving cheese(s) with water and calcium sequestering salts followed by drying. The desirable characteristics of cheese powder are high solubility, no lumps, storage stability, and imparting a typical cheesy flavor to the final product. Many current studies on cheese powder are focused on reducing calcium-sequestering salts (CSSs) to reduce the sodium content of cheese powder. This review discusses the production processes and physio-chemical properties of cheese emulsions and powders, aiming to enhance current understanding and identifying potential research gaps. Furthermore, strategies for producing cheese powder without CSSs, including pH adjustment, homogenization, and addition of dairy components such as buttermilk powder and sodium caseinate, are elaborated upon. Processing variables such as heating conditions during the preparation of cheese emulsion may vary with the type and age of the cheese used and product formulation. These conditions also effect the characteristics of cheese powders. On the other hand, producing a stable cheese emulsion without CSSs is challenging due to impaired emulsification of fat. The combined use of buttermilk powder and sodium caseinate among various alternatives has shown promising results in producing cheese powder without CSSs. However, future research on replacing CSSs should focus on combining two or more strategies together to produce cheese powder without CSSs. The combination of pH adjustment and dairy ingredients and the use of novel processing technologies with different ingredients are interesting alternatives. Full article

The surge in kitchen waste production is causing food-borne disease epidemics and is a public health threat worldwide. Additionally, the effectiveness of conventional treatment approaches may be hampered by KW’s high moisture, salt, and oil content. Hydrothermal carbonization (HTC) is a promising new technology to convert waste biomass into environmentally beneficial derivatives. This study used simulated KW to determine the efficacy of hydrothermal derivatives (hydrochar) with different salt and oil content, pH value, and solid-liquid ratio for the removal of cadmium (Cd) from water and identify their high heating value (HHV). The findings revealed that the kitchen waste hydrochar (KWHC) yield decreased with increasing oil content. When the water content in the hydrothermal system increased by 90%, the yield of KWHC decreased by 65.85%. The adsorption capacity of KWHC remained stable at different salinities. The KWHC produced in the acidic environment increases the removal efficiency of KWHC for Cd. The raw material was effectively transformed into a maximum HHV (30.01 MJ/kg). HTC is an effective and secure method for the resource utilization of KW based on the adsorption capacity and combustion characteristic indices of KWHC. Full article

This work reports a new finding on the effect of dissolved salts, in water-air mists, on spray heat removal efficiencies from a metallic surface under steady state conditions. The experimental system is based on a calorimeter that measures heat flux removed by water-air mist sprays from 8 mm diameter × 2.5 mm thickness platinum samples heated by electromagnetic induction. During steady-state experiments, a solid-state controller equilibrates automatically the rate of heat generation with the rate of heat removal to reach a constant temperature. Equilibrium temperatures for stepwise T rising include 200 to 1200 °C in steps of 100 °C and then stepwise T that is lowered to 200 °C. The new finding is that, when using soft water-air mist and a high-water impingement density, a lack of temperature control during stepwise T increases was observed when stepping from 200 to 300 °C. This lack of temperature control is associated with a high heat flux and is attributed to the stabilization of the single-phase convection regime when T rising from 200 to 300 °C. Temperature stabilization was again possible only at wall temperatures ${\mathrm{T}}_{\mathrm{w}}\ge 600$°C, at which single-phase convection was not stable. In contrast, when using a hard water-air mist under the same fluid flow conditions, all temperatures were readily reached. This is attributed to the transition from single-phase convection to nucleate boiling regime when T increased from 200 to 300 °C. This transition leads to a decrease in heat flux due to a reduction in the contact area between liquid and the wall surface. Finally, the corresponding boiling curves at high wall temperatures show the importance of heat radiation from the wall to understand the effect of salts during the stable vapor film regime. Full article

Nickel-Fe₃O₄ nanoparticles supported on multi-walled carbon nanotubes (Ni-Fe₃O₄/MWCNTs) were synthesized by mechanical grinding of a sample of nickel salt, Fe₃O₄ and MWCNTs using a ball-mill mixer. The preparation method allows for bulk production of Ni-Fe₃O₄ nanoparticles at room temperature without the necessity of any solvent or chemical reagent. The nanoparticles prepared by this method exhibit small particles size of 5–8 nm with uniform dispersion of nickel nanoparticles on the surface of multi-walled carbon nanotubes. The Ni-Fe₃O₄/MWCNTs demonstrated remarkable catalytic activity for Suzuki cross coupling reactions of functionalized aryl halides and phenylboronic acids with excellent turnover number and turnover frequency (e.g., 76,000 h⁻¹) using Monowave 50 conventional heating reactor at 120 °C within a very short reaction time of 15 min. The catalyst is air-stable and exhibits easy removal from the reaction mixture due to its magnetic properties, recyclability with no loss of activity, and significantly better performance than the other well-known commercial nickel catalyst. The Ni-Fe₃O₄/MWCNTs nanoparticles were fully characterized by a variety of spectroscopic techniques including X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM) and X-ray Photoelectron Spectroscopy (XPS). Since nickel offers similar properties to other more expensive transition metals including the most widely used palladium counterpart in cross coupling catalysis, this work demonstrates a promising lower-cost, air-moisture stable and efficient alternative catalyst based on nickel nanoparticles for cross coupling reactions. Full article

The formation of heat stable salts (HSS) during the natural gas sweetening process by amine solvent causes many problems such as corrosion, foaming, capacity reduction, and amine loss. A modeling study was carried out for the removal of HSS ions from amine solution using nanofiltration (NF) membrane process that ensures the reuse of amine solution for gas sweetening. This model studies the physics of the nanofiltration process by adjusting and investigating pore radius, the effects of membrane charge, and other membrane characteristics. In this paper, the performance of the ternary ions was investigated during the removal process from methyl di-ethanol amine solution by the nanofiltration membrane process. Correlation between feed concentration and permeate concentration, using experimental results with mathematical correlation as C_i,p = f (C_i,f) was used in modeling. The results showed that the calculated data from the model provided a good agreement with experimental results (R² = 0.90–0.75). Also, the effect of operating conditions (including feed pressure and feed flow rate on ions rejection and recovery ratio across the flat-sheet membrane) was studied. The results showed that the recovery and rejection ratios of the NF membrane depend on the driving pressure across the membrane. While the driving pressure is affected by the feed flow conditions and feed pressure. Full article

This study presents an efficient and scalable process for removing the heat-stable salts (HSS) ions from amine solution while recovering methyl diethanolamine (MDEA) solution for its reuse in gas sweetening plants. The presence of HSS in the amine solution causes the loss of solvent capacity, foaming, fouling, and corrosion in gas sweetening units so their removal is crucial for a more well-performing process. Furthermore, the recovery of the amine solution can make the sweetening step a more sustainable process. In this study, for the first time, the removal of a multicomponent mixture of HSS from MDEA solution was investigated via a nanofiltration process using flat-sheet NF-3 membranes. The impact of operating parameters on salts and amine rejection, and flux, including the operating pressure, HSS ions concentration, and MDEA concentration in the feed solution was investigated. Results based on the nanofiltration of an amine stream with the same composition (45 wt.% MDEA solution) as that circulating in a local gas refinery (Ilam Gas refinery), demonstrated a removal efficiency of HSS ions in the range from 75 to 80% and a MDEA rejection of 0% indicating the possibility of reusing this stream in the new step of gas sweetening. Full article

Heat stable salts (HSS) formed and continuously accumulated in the amine-based solvents due to solvent degradation and impurities in the feed gas can dramatically change the efficiency of the amine scrubbing process. HSS can be removed by using different methods including membrane separation such as electrodialysis (ED). In this work, we studied the effect of CO₂ loading of the lean 30 wt % monoethanolamine (MEA) solution on the efficiency of HSS removal and MEA loss. In the model MEA solution containing HSS on the level of 48 meq/L, the carbon dioxide concentration was varied from 0.2 down to 0 mole (CO₂)/mole (MEA). The reclaiming of model MEA solution was carried out by lab-scale two-stage ED unit when the concentrate stream after the first stage was additionally treated using ED (second stage) that allowed reducing MEA loss. It was shown that the decrease of carbon dioxide content from 0.2 down to 0 mole (CO₂)/mole (MEA) resulted in a substantial reduction of both parameters—the MEA loss and the specific power consumption with respect to extracted HSS (from 140 down 37 kJ per 1 g of recovered HSS anions). This can be explained by the drop in the total concentration of ions formed by the interaction of MEA solution with carbon dioxide. However, the change of CO₂ loading is associated with additional power consumption towards further solvent regeneration in the column. Based on the preliminary estimations of power consumption required for additional CO₂ stripping with the respect to the power consumption of ED stage, it seems that lean solvent CO₂ loading of 0.1 mole/mole provides an optimum for the power input at 25.9 MJ/kg(solvent). Full article