Analysis of the Mass Transfer in Acid Decomposition of Phosphorus-Containing Raw Material

2003 ◽  
Vol 37 (6) ◽  
pp. 601-605
Author(s):  
S. V. Dobrydnev ◽  
V. V. Bogach ◽  
V. S. Beskov
Keyword(s):  
Mass Transfer ◽  
Raw Material ◽  
Acid Decomposition ◽  
Phosphorus Containing

scholarly journals Processes of heat and mass transfer during drying of red beetroot

2020 ◽  
Vol 6 (2) ◽  
pp. 81-87
Author(s):  
Zhanna Petrova ◽  
◽  
Kateryna Samoilenko ◽  
Vitaly Vishnevsky
Keyword(s):  
Mass Transfer ◽  
Energy Consumption ◽  
Heat And Mass Transfer ◽  
Raw Materials ◽  
Antioxidant Properties ◽  
Calculation Model ◽  
Experimental Results ◽  
Biologically Active ◽  
Raw Material ◽  
Drying Process

Red beetroot is the main raw material which has a high content of betanine with antioxidant properties. An important emphasis in the processing of antioxidant raw materials by drying is to reduce energy consumption for the dehydration process, the maximum preservation of biologically active substances, and to reduce the cost of the final product. Drying is a complex and energy-intensive process. Therefore, to optimize energy consumption during drying and selection of rational modes of dehydration, it is necessary to apply the calculated analysis of heat and mass transfer on the basis of adequate mathematical models. Calculated and experimental results are compared. In general, the comparison of the results of numerical modeling of convection drying processes of the red beetroot sample with the experimental results showed their rather satisfactory qualitative agreement. The calculation model can be used to approximate the characteristics of the drying process of red beetroot, in particular the time required for drying. The obtained results of calorimetric studies allow stating that with correctly selected compositions, not only the components of native raw materials are stabilized, but also the drying process is intensified with the reduction of energy consumption to process.

scholarly journals PHOSPHORUS-CONTAINING SORBENT ON THE BASE OF CELLULOSIC RAW MATERIAL

2017 ◽  
Vol 0 (1) ◽  
pp. 84-90
Author(s):  
Микола Дмитрович Гомеля ◽  
Олександр Петрович Хохотoв ◽  
К. А. Малихіна
Keyword(s):  
Raw Material ◽  
Phosphorus Containing

Target Kappa Number for AS/AQ Pulping of Wheat Straw

2011 ◽  
Vol 236-238 ◽  
pp. 1431-1436
Author(s):  
Jing Liu ◽  
Katsuya Nagata
Keyword(s):  
Mass Transfer ◽  
Wheat Straw ◽  
Transition Point ◽  
Phase Transfer ◽  
Raw Materials ◽  
Kraft Pulping ◽  
Kappa Number ◽  
Experimental Results ◽  
Raw Material ◽  
Pulp Yield

Alkaline sulfite/anthraquinone (AS/AQ) pulping of wheat straw under different conditions was conducted in this study. A transition point of kappa number at approximately 6.5 was observed based on all experimental results. This transition point can be regarded as the phase transfer point in AS/AQ pulping from bulk to residual delignification. Effective delignification without great lost of pulp yield can be achieved before kappa number was below this transition point during AS/AQ pulping of wheat straw. It is found that the ratio of cooking liquid to solid should not be lower than 6, if good mass transfer of chemicals and lignin dissolving is needed. As the ratio of Na2SO3 to NaOH dosage ranged from 0.4 to 2.4, low proportion of Na2SO3 allows effective delignification while no serious degradation of carbohydrate. Moreover, similar to kraft pulping, addition of AQ in the range of 0.05% to 0.25% is useful to remove lignin and protect the carbohydrate during AS/AQ pulping. Finally, although the transition point of kappa number may be changed while different raw material used for same pulping process or different pulping process for same raw materials, it is of interest and important for mill practice.

Synthesis of biobased phosphate flame retardants

2014 ◽  
Vol 86 (11) ◽  
pp. 1637-1650 ◽  
Author(s):  
Raphaël Ménard ◽  
Claire Negrell-Guirao ◽  
Laurent Ferry ◽  
Rodolphe Sonnier ◽  
Ghislain David
Keyword(s):  
Flame Retardant ◽  
Epoxy Matrix ◽  
Flame Retardants ◽  
Raw Material ◽  
Phosphorus Containing ◽  
The Matrix ◽  
Flame Retardant Properties ◽  
Combustion Flow ◽  
Hydroxy Groups ◽  
Modified Epoxy

Abstract An approach to prepare some biobased flame retardant (FR) compounds is presented. The adopted strategy consists in functionalizing an aromatic biobased phenolic compound, the phloroglucinol, with different phosphate groups in order to promote a charring effect. Different chlorophosphates were grafted onto phloroglucinol hydroxy groups and the functionalization of the hydroxy groups was quantitative. The synthesized biobased FR were incorporated into an epoxy matrix as additive to estimate their flame retardant properties. The influence of different parameters was studied such as the phosphorus content of the thermoset or the nature of the R group of the used phosphate P-O-R. MEB/EDX observations proved the influence of this R group on the compatibility between the FR and the matrix and its importance to obtain homogeneous thermoset. Thermogravimetric analyses of the phosphorus-containing thermosets showed a small decrease in thermal stability accompanied by a char yield almost tripled for a 3 %wP-containing thermoset compared to that of the thermoset without any FR. Pyrolysis combustion flow calorimetry was also used to evaluate the flammability of the modified epoxy thermoset. A significant decrease in peak of heat release rate and total heat released was observed compared to thermoset without FR. These results demonstrate the good flame retardant properties of these biobased phosphates in an epoxy matrix. In addition these results show the potential of the biobased phenolic compounds as raw material for flame retardants syntheses.

scholarly journals RESEARCH ON THE MECHANISM OF MELANOIDIN ADSORPTION KINETICS FROM AQUEOUS SOLUTIONS BY CARBONIC ADSORBENTS

2017 ◽  
pp. 40-43
Author(s):  
Kseniya Zelenaya ◽  
Kseniya Zelenaya ◽  
Nadezhda Golubeva ◽  
Nadezhda Golubeva ◽  
Alena Khlopova ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Wastewater Treatment ◽  
Aqueous Solutions ◽  
Porous Structure ◽  
Adsorption Kinetics ◽  
Negative Impact ◽  
Homogeneous Model ◽  
Raw Material ◽  
External Mass Transfer ◽  
Pharmaceutical Industries

Melanoidins are widely used in food and pharmaceutical industries. Melanoidins, which get in water bodies with wastewater of plants, pollute them, which subsequently can have a negative impact on the population health. Wastewater treatment of plants is an important condition to preserve the integrity of aquatic ecosystems. Sorption filtration is the most effective way of removing organic substances among the methods, used for wastewater treatment. To study the adsorption kinetics, the carbonic sorbents of the brands ABG and Purolat-Standard were used, which differ with a raw material, a surface chemistry state and a porous structure. The study of the adsorption kinetics allows to determine the mechanism of mass transfer in the system adsorbent-adsorbate and to obtain the parameters, necessary for engineering evaluation of adsorption processes in practice. It is shown that the time of reaching equilibrium in the sorption system varies in the range of 150-250 minutes. The degree of reaching the adsorption equilibrium () and the dimensionless kinetic parameters T have been calculated, which are proportional to the time of the process (t). It is found that the melanoidin adsorption rate is controlled by external mass transfer, necessary for calculation of optimum parameters and modes of the adsorption process. Experimental research allows to determine that the granules of the used carbonic sorbents interact with the dissolved substance in the full volume and throughout the particle is in the reaction zone; such interaction relates to a quasi-homogeneous model. It is shown that at the melanoidin adsorption, the rate of the internal diffusive mass transfer depends on the porous structure of the carbonic adsorbents. A high value of the external mass transfer coefficient for the carbonic sorbent Purolat-Standard suggests a high degree of melanoidin extraction from aqueous solutions.

scholarly journals Modeling the extraction process of medicinal raw materials

2020 ◽  
Vol 100 (4) ◽  
pp. 135-144
Author(s):  
I.А. Khabarov ◽  
◽  
V.V. Zhurov ◽  
А.N. Zhabayeva ◽  
S.М. Adekenov ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Mathematical Models ◽  
Raw Materials ◽  
Extraction Process ◽  
Individual Characteristics ◽  
Solid Particles ◽  
Biologically Active ◽  
Raw Material ◽  
Target Component ◽  
Extraction Processes

The review considers 26 mathematical models of the process of biologically active substances extraction from medicinal plant raw materials, taking into account factors affecting the extraction process: diffusion coefficient, particle size, layer porosity, extractant feed rate, raw material grinding method, pressure, temperature and duration of extraction, individual characteristics of raw materials (content of the target component) and technological equipment. In general, these models fall into four important groups: empirical models, models based on heat transfer analogies, a shrinking core model, and models based on differential mass bal-ance. Here were described problems that occur in the selection of mathematical models, first of all, associated with the imperfect behavior of the flows of extraction liquids, and the inhomogeneous cross-section of the extraction apparatus. It was shown that first of all the extraction process modeling requires mathematical models to describe the mass transfer inside solid particles. It is also important to take into account the solubility of the target substances when simulating. It is shown that for describing the extraction processes, the optimal models are Naik and Lentz, Esquivel, diffusion, H. Sovová mass transfer, damaged and undamaged cells for calculating the main factors of extraction processes.

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