Drying and conditioning viscose staple fibre

Conclusions With respect to the mechanism of moisture removal, the process of drying viscose staple fibre is divided into two stages. The first stage takes place at a constant rate. Removal of moisture takes place by the mechanism of evaporation from a free surface. In the second stage, mainly solvated bound water is removed, by a desorption mechanism, which is described by an equation for a first order chemical reaction.The main factor which determines the kinetics of fibre drying in the second state is temperature. At a temperature of 100–120°C, the amount of air delivered to the second dryer can be reduced from 14,000–16,000 to 3,000–5,000 m³/h.The significant effect of the degree of fibre loosening on drying kinetics has been demonstrated.Translated from Khimicheskie Volokna, No. 6, pp. 28–32, November–December, 1986.     

Selection of microporous adsorbents for the clean-up of manufacturing waste water

Conclusions -- A procedure has been developed for selecting microporous sorbents for the clean-up of waste water, which takes into account overall the diverse technological characteristics of adsorbers.-- The procedure has been checked out as applicable to selecting carbon sorbents for cleaning up caprolactam-containing waste water in the manufacture of polyamide fibres.Translated from Khimicheskie Volokna, No. 5, pp. 24–27, September–October, 1990.     

Effect of intensive drying of viscose fibres on their properties

Conclusions Experimental data are given on the effect of moisture evaporation rate in drying viscose yarns on the strength and elongation, sorptive capacity for water vapor from the air, swelling, shrinkage, and wear resistance of yarns.It has been found that, by regulating the drying temperature, it is possible to affect the capillary-porous structure of a yarn to a considerable degree. Raising the temperature and the drying rate leads to an improvement in wear resistance and yarn elasticity. However, due to the decrease in internal surface area, one may expect a decrease in the sorptive capacity of the yarn in dyeing. A decrease in drying temperature helps increase the degree of swelling, and helps improve the absorption of dye by the yarn.Translated from Khimicheskie Volokna, No. 2, pp. 46–47, March–April, 1984.     

Effect of heat-treatments and elevated humidity on the electrical conductivity of metallized nitron fibre

Conclusions The effect of drying conditions and heat-setting conditions on the electrical resistance of various specimens of metallized Nitron fibre has been investigated. It has been shown that, to prevent intensive oxidation of the metallic coating, it is necessary to carry out drying of the fibre under a dynamic regime at 120–140°C, with forced removal of the evaporated moisture.It has been found that subsequent heat-setting of the fibre is favorably reflected in the stability of its electrophysical properties under conditions of elevated humidity.Fibres which have been coated with an additional layer of galvanic nickel have the most stable electrophysical properties, which permits one to recommend them for practical use.Translated from Khimicheskie Volokna, No. 6, pp. 12–14, November–December, 1987.     

Some features of contact-convective drying of viscose yarn

Conclusions Expenditures of heat in drying individual viscose textile yarns have been studied as a function of the construction of the device for condensated withdrawal from the type PNSh machines.It has been shown experimentally that a drying cylinder with siphon condensate withdrawal and a gas removal tube for removal of gases which are insoluble in the condensate reduces the consumption of heat in drying, increases the temperature of the contact surface, and aids in a more uniform temperature distribution.Translated from Khimicheskie Volokna, No. 4, pp. 35–37, July–August, 1988.     

Effects of acid pretreatments on some physicochemical properties of carrot undergoing hot air drying

Carrot is one of the important root crops cultivated worldwide. In many cases, carrot must be dried prior to its use. Although hot air drying is one of the most common methods for drying carrots, it is well known that hot air drying leads to much quality degradation of a dried product. To alleviate the adverse effect of hot air drying many pretreatment methods have been proposed. In this study, the effects of pretreatments with citric acid, which is used as an anti-darkening agent and a texture-modifier, were investigated. Carrots were soaked in citric acid to pH of either 4 or 5 or blanched in citric acid to pH of either 4 or 5 prior to hot air drying. Untreated carrots, carrots soaked in water and carrots blanched in water were used as control samples. The effects of pretreatments, in combination with hot air drying at 70, 80 and 90 °C, on selected physicochemical properties of dried carrots, namely, color, shrinkage, rehydration ability, β-carotene content and cis–trans isomerization of β-carotene, were evaluated. It was noted that carrots, which were soaked and blanched in citric acid, were redder than the untreated sample. Although shrinkage of pretreated carrots was higher, the rehydration ability of the pretreated carrots was higher than that of the untreated sample. The β-carotene content of carrots with no pretreatment decreased continuously, whereas the contents of β-carotene in citric acid soaked and blanched carrots tended to be unchanged. However, isomerization of β-carotene in all samples was not significantly different.     

Effect of the structure of the elementary filaments on the tension of complex viscose yarns during drying

Conclusions The effect of the structure of the elementary filaments on the tension of a complex viscose yarn during drying has been investigated.It has been found that the tension of viscose yarn during drying under isometric conditions is increased with increase in the proportion of skin in a transverse section of the elementary filaments.Translated from Khimicheskie Volokna, No. 1, pp. 27–28, January–February, 1986.     

Theoretical and experimental foundation for the possibility of a combined process of drying and conditioning viscose fibres

Conclusions The possibility of using a theoretical probability model equation for predicting values of water vapor sorption at elevated temperature for high-modulus viscose fibres has been shown.It has been shown that at a drying agent temperature of 80–100°C and a relative humidity of 70%, a fibre moisture content of 11–13% is attained, which corresponds to conditioned humidity.Translated from Khimicheskie Volokna, No. 5, pp. 42–43, September–October, 1988.     

Expenditure of heat energy in drying viscose textile yarns

Conclusions It has been found that the thermogravimetric analysis method is applicable for determining the expenditure of thermal energy in desorbing moisture from hydrocellulose textile fibres; it gives a quantitative evaluation of the fractional composition of the water sorbed by the yarns and of its bonding energy with the yarn matrix.The change in consumption of heat energy at various extents of drying of freshly-spun viscose textile yarns has been studied.It has been found that extensive drying of yarns, to a moisture content significantly lower than the conditioned values, that is, overdrying, requires elevated, unjustified expenditures of heat energy.Translated from Khimicheskie Volokna, No. 4, pp. 43–44, July–August, 1987.     

Reasons for the retention of long-term antistatic properties of polyacrylonitrile fibre which has been modified at the gel stage with polyethylene glycol-9 diacrylate

Conclusions The reasons for the resistance of the antistatic properties of polyacrylonitrile fibre, which has been modified at the gel stage with a polyethylene glycol diacrylate, to boiling washes have been investigated.It has been suggested that the retention of the antistatic effect is caused by the manifestation of a cryptoheterogeneity effect under the washing conditions and by the possibility of migration of the antistat from the fibre pores into its surface under definite drying conditions.Translated from Khimicheskie Volokna, No. 2, pp. 33–35, March–April, 1987.     

Effect of addition of dyes to brightening-lubricating compositions of properties of viscose fibres

Conclusions It has been found that a content of certain dyes in the brightening-finishing composition exerts and important effect on phenomena which take place during the drying of the freshly spun fibres.The introduction of additives in dyeing ensures obtained fibres of increased strength.The analogy in action of dyes and some organic and inorganic substances which we have previously investigated indicates a large role for the addition of such substances in the course of the process of drying freshly spun fibres, regardless of features in their structure.Translated from Khimicheskie Volokna, No. 4, pp. 54–56, July–August, 1989.     

The drying kinetics of seeded grape in solar dryer with PCM-based solar integrated collector

This paper presents a novel type of dryer for experimentally evaluating the drying kinetics of seeded grapes. In the developed drying system, it has been particularly included an expanded-surface solar air collector, a solar air collector with phase-change material (PCM) and drying room with swirl element. An expanded-surface solar air collector has been used to achieve high heat transfer and turbulence effect whiles a solar air collector with PCM has been used to perform the drying process even after the sunset. On the other hand, the swirl elements have been located to give the swirl effect to air flow in drying room. These advantages make the proposed novel system a promising dryer in that lower moisture value and less drying time. The drying experiments have been carried out simultaneously both under natural conditions and by the dryer with swirl flow and without swirl flow at three different air velocities. The obtained moisture ratio values have been applied to six different moisture ratio models in the literature. The model having the highest correlation coefficient (R) and the lowest Chi-square (χ²) value has been determined as the most relevant one for each seeded grape drying status.     

Reconstruction of a frame filter press for bubbling wash-out of filter elements

Conclusions A construction has been described, and a procedure for calculating air distributing devices has been given, which will ensure uniform distribution of compressed air in the volume of a filter press during bubble washing of its charge.It has been found that the use of these devices permits one to increase the amount of viscose washed out of the filter material by 10%.Translated from Khimicheskie Volokna, No. 5, pp. 48–51, September–October, 1987.     

Some peculiarities of the copolymer precipitation in spinning a strongly-acid chemisorptive fibre

Conclusions The existence of polyelectrolyte swelling (self-elongation of the fibre on change of medium) has been established in strongly acid undrawn gel-fibre.It has been shown that cementing of the strongly-acid fibre after drying, when the fibre has been wet-spun into aqueous-organic baths, is caused by the presence of solvent which is strongly retained on the fibre.A possible mechanism for the retention of solvent by the strongly-acid gel-fibre has been advanced.Translated from Khimicheskie Volokna, No. 4, pp. 32–34, July–August, 1987.     

Effect of drying conditions on the properties of tire-cord yarn

Conclusions -- The drying conditions of technical yarn on a PN-300-IZ machine, where the yarn has been prepared from spinnerets having 2200 holes, has been investigated.-- The optimum yarn length on the drying cylinders has been determined with simultaneous and mandatory holding of the packages in a conditioning chamber before delivery to the twisting works.Translated from Khimicheskie Volokna, No. 5, pp. 27–29, September–October, 1990.     

Adsorption of resorcinol and catechol on granular activated carbon: Equilibrium and kinetics

Investigations were conducted in the batch mode for studying the adsorption behavior of resorcinol and catechol on granular activated carbon from a basic salt medium (BSM) at pH≈7.1 and temperature≈30 °C. The isotherm data were correlated with six isotherm models, namely Langmuir, Freundlich, Redlich–Peterson, Radke–Prausnitz, Toth, and Fritz–Schlunder’s using a nonlinear regression technique. It is observed that the catechol isotherm data may be represented by Redlich–Peterson, Radke–Prausnitz, Toth, and Fritz–Schlunder models with similar accuracy (max. dev. 12%). And the resorcinol data may be represented by Freundlich, Redlich–Peterson, Radke–Prausnitz, and Fritz–Schlunder models equally well (max. dev. 15%). Freudlich being a simple model is recommended for resorcinol. At the conditions investigated in this study, catechol is adsorbed to a greater extent than resorcinol. This is due to the compound’s solubility and position of the –OH group on the benzene aromatic ring. The kinetics of adsorption have been found to be diffusion controlled and the value of effective particle diffusion coefficients is of the order of 10⁻¹³ m²/s. Three distinct phases of kinetics—rapid, medium, and slow—have been observed. These results should be useful for the design of adsorbers for removing these pollutants.     

Drying of gas—Air mixtures with Vion KN-1 chemisorption fibre

The use of Vion KN-1 chemisorption fibre in hydrogen form as a selective drying agent for a gas—air mixture containing sulfur dioxide, carbon monoxide, hydrogen sulfide, and nitrogen dioxide was substantiated. The optimum conditions of use and regeneration of the drying agent were determined.Scientific-Research Institute of Physics at Odessa State University. Translated from Khimicheskie Volokna, No. 1, pp. 40–43, January–February, 1994.     

Double drying of polyacrylonitrile fibres for technical purposes

Conclusions -- The kinetics of double drying of polyacrylonitrile tow has been studied.-- An empirical equation has been obtained for determining the drying time as a function of the temperature of the heating surface.Translated from Khimicheskie Volokna, No. 3, pp. 58–59, May–June, 1991.     

循环流化床中C类颗粒的干燥

为将循环流化床(CFB)技术应用于C类颗粒(＜30μm)的干燥,在自建的循环流化床(内径0.104 m×高2.35 m)内,以玉米淀粉(dp=8 μm,ρp=800 kg/m3)为研究对象,考察了不同操作参数对其干燥特性及干湿分离情况的影响.结果表明:循环流化床适用于C类颗粒的干燥;干燥速率随气速及进风温度的增大而增大...     

Drying Kinetics in the Riser of Circulating Fluidized Bed with Internals

Solid particles were dried in the riser of circulating fluidized bed with internals to study the drying kinetics. Experiments were conducted in a circulating fluidized bed, having perforated plates as internals covering wide range in the operating parameters. The effects of various operating parameters, i.e., initial moisture content, temperature, and flow rate, of the heating medium and solid circulation rate on the rate of drying have been critically examined. It has been observed from the present investigation that the presence of internals enhances the solids holdup in the riser of circulating fluidized bed. The drying efficiency of a circulating fluidized bed with internals has been compared with the drying performance of a circulating fluidized bed without internals under the same operating conditions.