SU1042781A1 - Method of agitating with liquid - Google Patents

Abstract

A method of mixing gas with a liquid, including transferring gas into the apparatus and circulating liquid through a refractory gas, characterized in that, in order to intensify the mixing process and reduce energy consumption, stirring is performed when the liquid 6 of the apparatus is released to the volume of the apparatus at the level of overflow partitions equal to O, 8-O, 9.

Description

The invention relates to methods for mixing gas with a liquid in capacitive apparatuses and can be used in the chemical, petrochemical, microbiological and other industries. It is known that the efficiency of a chemical reaction, between liquid and liquid, ceteris paribus x, largely depends on the size of the interfacial contact surface, which is mainly determined by the gas content of the liquid. The gas content of a liquid depends on the method of mixing and gas. With a liquid. The wide distribution of the gas in the apparatus by mixing a liquid in a closed loop through an overflow wall and feeding the pelvis into the apparatus. There is a method in which the circulation of fluid in a closed loop is accomplished by 6 using various turbine devices. Cl. However, the disadvantage of this method is that the gas retention capacity of the circulating flow of the bone is due to the low speed of its circulation created by turbine type devices. There is also known a method of mixing gas with a liquid, which includes the supply of gas to the apparatus and the circulation of liquid through the overflow partition. This method, due to the rather high speeds of circulation of the fluid created by the helical stirrer, increases the retention capacity of the liquid through the gas, and hence its gas content. 23. The disadvantage of this method is the low gas content of the liquid 5-6 and a large dependence gas content from gas flow through the apparatus, as well as significant energy consumption. This is due to the fact that in carrying out the method, the volume of liquid is maintained at an equal or greater volume of the apparatus at the level of the overflow partition. The chain of the invention is to intensify the mixing process and reduce energy consumption. The goal is achieved. According to the method of mixing gas with liquid, including: to whom the gas flows into the apparatus and the circulation of liquid through the overflow partition, mixing is carried out at the ratio of volume, liquid to apparatus - to the volume of the apparatus at the level of an overflow partition equal to 0.8-O, 9. FIG. 1 shows a scheme for drying the process in an apparatus with an internal overflow annular partition 1 and a helical stirrer; in fig. 2 - dependence of gas content on air velocity; in fig. 3 shows the dependence of the power consumed by the screw stirrer and the reaction rate on the filling ratio of the apparatus. The apparatus is filled with a volume fluid MOMV., Smaller than its volume at the level of the overflow partition V., p. In this case, the initial level of the liquid HVJ, in the apparatus is below the level of the overflow partition H, the helical stirrer 2 is set in rotation. Under its influence, the fluid rises along the annular partition 1 and begins to overflow over its upper edge. As a result, a continuous circulation of bone & bones in the apparatus along a closed contour occurs. . Due to the sufficiently high rate of fluid circulation, the gas enclosed in the volume between the initial liquid level in the static state H; j {and the level of its overflow through the overflow partition Hp, is carried away by the fluid flow, is dispersed and evenly distributed in it, forming homogeneous gas-liquid mixture. The gas content of the liquid in this case is determined by the ratio of the volume of the liquid in the apparatus V ,, .H, j F to the volume of the gas-liquid mixture formed by the circulation of the liquid. For the same cross-section of the apparatus, the gas content is equal to the ratio of the heights H, pk Hp;,; -; p. .. When the device is filled above the level of the overflow partition in the static state V, / VPJ, 1.2), the gas squeeze of the circulating liquid without supplying the gas to the device is zero. As the volume of the liquid in the apparatus decreases, the gas content of the resulting gas-liquid mixture continuously increases and amounts to 5-6% dp),; ,,,, 0 and 32-33% n nflVjjf /, 72. A further decrease in the volume of fluid in the apparatus leads to a discontinuity in the continuity of the gas – fluid flow when it is rotated through the upper edge of the overflow circuit. The filling of the apparatus I, corresponding to L / Vy, (| K) 72, is the minimum allowable al to ensure effective mixing of the gas with the blast. Thus, when the ratio changes from 1.2 to 0.72, the gas retention of the circulating flow can vary from about 33%. In aHana3OHeV., / Vnn-Oi8-O 9, the gas is mixed efficiently with the liquid and a high gas content of 15-25% of the circulating stream of the gas-liquid mixture is obtained even without the gas supply. Moreover, the gas supply to the apparatus in this case has little effect on the total gas flow, increasing it by 2-5%. Thus, the proposed method of mixing gas with a liquid by circulating it through an overflow partition while maintaining the well filling device in the range V; j, / Vf, f, 0.8-0.9, allows to significantly increase the gas content of the liquid and reduce gas consumption to obtain the required gas content, i.e. reduce energy costs. The specified volume of fluid in the apparatus when circulating it in a closed loop is supported by known methods, adjusting, for example, the rate of fluid withdrawal from the tank by weight of the column, gas-liquid mixture or using a free overflow with a given height HQ overflow, as shown in FIG. Example. Air is mixed with water in a 2OO liter apparatus with a diameter of 400 mm, having a circular wall of 250 meters in diameter and a screw mixer with a diameter of 150 mm with a pitch ratio of a screw mixer of 0.8. The frequency of rotation of the agitating shaft is 46.7 1 / s. The air velocity referred to the cross section (the body of the apparatus varies from 0 to 0.07 m / s. The ratio varies from 1.2 to 0.75. Fig. 2 shows the experimental dependences of the gas content on the velocity in air the apparatus for different fillings: 1 1.2; 2 -Vjc / ymrl.p; 3 .94; 4 -.C ,, 88 | 5 4 / Vnn0 .85; 6 ,, 82;. 7 -V ,,., 76 ; 8 .75.. The gas content when filling the device at or above the level of the overflow partition is Q-15% and depends on the air velocity (curves 1 and 2), npHV ,, 0 gas-containing liquid increases significantly degree depends on air velocity in app In the proposed range (curves 4–7), an effective mixing and high gas content of 17–30% is provided. Example 2. The process of hydrogenation of an aqueous solution of glucose in a 0.63 m apparatus with an internal ring overflow partition and stirring screw is carried out. The initial level of the glucose solution in the static state was set below the overflow partition by 500 mm. Hydrogen for hydrogenation of glucose was supplied to the gas phase of the apparatus. Pressure in ap. a pair of those is 6O kgf / cm. The process is periodic without fluid flow. ; After the helical stirrer is turned off, the hydrogen in the volume between the initial level of glucose solution in the apparatus and the level of its overflow through the annular partition is involved in the circulation and dispersed in the solution. The average gas content is 2O%. Due to high gas retention, hydrogen consumption is reduced. At. This consumption of hydrogen is determined only by the rate of chemical reaction. Under these conditions, the duration of the hydrogenation process does not exceed 1.2-1.5 hours. In the case of maintaining the process at the initial level of glucose solution above the overflow partition, despite a significant increase in hydrogen consumption over the need for a chemical reaction, gas confinement of the liquid is doubled; less, and the duration of the process is 2.0–2.5 hours. Tests were carried out on various media: hydrogenation of an aqueous solution of glucose in the WP 0.63–6.4 unit with a volume of 0.63 m; reduction of nitro compounds with hydrogen in the apparatus FT 2.5 5, 4 with a volume of 2.5 sulfonation of oils with carbon dioxide in the apparatus WG 40, 6 with a volume of 4 m,. . As a result of the tests, it was found that in all apparatus, regardless of the composition of the working medium, there is the same extreme dependence of the power consumed by the helical stirrer on the fill factor with a pronounced minimum in the range (0.8 - 0.9) K (Fig. 3); Ana / Logical type has a dependence of reaction time on a factor of i -

1042781

apparant K. The minimum reaction time is austage. also at QY. 3, 9, and its value is determined by the kinetics of the process (Fig. 3).

Thus, the proposed method of mixing gas with a liquid makes it possible to significantly im- plement the flow, cc and reduce energy consumption.

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Claims (1)

METHOD FOR MIXING A GAS WITH LIQUID, including supplying gas to the apparatus and circulating the liquid through the overflow partition, characterized in that, in order to intensify the mixing process and reduce energy consumption, the mixing is carried out with the ratio of the volume of fluid in the apparatus to the volume of the apparatus at the level of the overflow partition, equal to 0.8-0.9. Fio. 1 SU .1042781> apparatus for a closed sufficiently high speed liquid gas