RU2522609C2 - Reactor for obtaining chlorine dioxide solution - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: reactor for obtaining a chlorine dioxide solution with three flow chambers, located successively in vertical, separated with partitions with through channels, with branch pieces for discharge of the chlorine dioxide water solution in the upper chamber and branch pieces for supply of reagents and discharge of a reaction solution in the lower one, with a possibility of placing nozzles, for instance, Raschig rings in the middle chamber. Chambers are of a round shape with changeable curvature of an internal surface, and their volume increases from the lower to the upper one. Partitions are made in the form of a surface of a directed downward cone with rims in the base, in which radial channels from an external edge to the centre are made. The lower partition, in comparison with the upper one, is characterised by a smaller diameter and larger height of rim, a larger length and area of section of radial channels with their smaller number. A tube for connection of the chamber to external environment is located on the reactor axis. Branch pieces for supply of reagents are located in the cone-shaped part of the lower chamber and are directed tangentially to each other with displacement relative to the chamber centre.

EFFECT: invention makes it possible to ensure homogeneous distribution of a gas phase in the finished liquid solution.

3 cl, 3 dwg

Description

The invention relates to the production of chlorine-containing oxidizing agents used as reagents in the disinfection and purification of drinking water, wastewater, recycled water.

A device for producing chlorine dioxide is known [Patent RU No. 2268241, C01B 11/02. A method of producing chlorine dioxide. Publ. 01/20/2006], including a reactor equipped with feed lines for chlorate ions, hydrogen peroxide and acid and connected to an ejector equipped with a nozzle for running water and means for subsequently passing the running water through the ejector, at least partially, in a spiral or helical fashion. However, the proposed reactor with one reaction chamber is designed to work with large volumes of reagents (up to 100 kg / h of chlorine dioxide). The finished product at the outlet of such a reactor is a heterogeneous gas-liquid mixture. The simultaneous presence of heterogeneity of the gas-liquid mixture in the reactor and maintaining a high temperature in it can lead to local accumulations of high concentration of chlorine dioxide with the possibility of self-decomposition with characteristic local “pops”, which leads not only to a decrease in the amount of chlorine dioxide formed, but also to possible stability impairment reactor operation.

A device for the production of chlorine dioxide of another design is also known [Patent RU No. 2350550, C01B 11/02. Method and device for the production of chlorine dioxide. Published March 27, 2009], including a reactor, a circulation pipe passing through a heater, a hole for supplying sodium chlorate directly to the reactor, holes for supplying sulfuric acid and hydrogen peroxide to the circulation pipe, a hole for supplying hydrogen peroxide directly to the reactor. The functions of the reactor in this device are also carried out by the circulation pipeline, in which, as in the reactor, the reactants interact, their significant (30-100 ° C) heating is carried out and chlorine dioxide is formed. The device, which is a unified system of "reactor-circulation pipeline - flow heater - circulation pump", is large-sized and imposes additional requirements on all constituent nodes, in particular, the possibility of their operation in conditions of vacuum, elevated temperatures, rapid evolution of chlorine dioxide during the reaction possible local accumulations with rapid self-decomposition of a circulating chemically active gas-liquid medium.

The closest analogue adopted for the prototype is a reactor for producing a solution of chlorine dioxide and chlorine in water [Patent RU No. 2307067, C01B 11/02. A method of obtaining a solution of chlorine dioxide and chlorine in water and a reactor for its implementation. Publ. September 27, 2007], including at least two chambers made flow-through, arranged successively vertically and separated by partitions in the form of a cone surface directed by the apex alternately up and down, with holes made in partitions directed upward by the top of the cone, and in partitions located with the top of the cone down, along the outer edge of the partition, with blades located in the lower and upper chambers, interconnected by at least one shaft parallel to the vertical on the axis of the reactor, between the upper and lower chambers there may be a chamber filled with a nozzle, for example, Rashig rings, in the upper chamber there are nozzles for supplying and discharging water, and in the lower chamber there are nozzles for supplying reagents and for draining the reaction solution.

The disadvantages of this reactor include the method of mixing the gas-liquid mixture (rotating blades). With this method of mixing, the weak flow of water used to rotate the blades and the friction at the places of installation of the shaft slows their rotation or stops. In this case, insufficient dispersion of the gases occurs. Their local accumulations with a high concentration are also possible, which leads to their arbitrary self-decomposition with characteristic “pops”, a decrease in the amount of chlorine dioxide produced and the stability of the reactor. An excessively strong flow of water can lead to an undesirable increase in pressure in the reactor, a change in the flow of gases and liquids in the chambers of the reactor, and the stability of the reactor. In this case, the ingress of water into the lower chamber also increases, which leads to a decrease in the degree of decomposition of sodium chlorate and the production of chlorine dioxide. Changing the chlorine dioxide reactor productivity requires establishing a new optimal, experimentally determined flow rate of water supplied to the reactor. In addition, the performance of the reactor on chlorine dioxide is small and reaches 3 g / h per 1 cm ^{2 the} cross section of the reactor. When greater productivity is achieved from 3 to 4 g / h, the degree of decomposition of sodium chlorate is reduced. When using the proposed reactor design to produce 1.5 kg / h of chlorine dioxide, which is not a large productivity, its internal diameter will increase significantly from 1 cm to obtain 1 g / h of chlorine dioxide to 25 cm, and the water flow through the reactor will reach a significant value ~ 7500 l / h. Such characteristics for installations of this type are too large and undesirable.

The objective of the invention is to develop a reactor for the production of chlorine dioxide with an average productivity (~ up to 1.5 kg / h of chlorine dioxide) with relatively small sizes, without moving elements and nodes, providing a uniform distribution of the gas phase in the finished liquid solution and requiring a relatively small amount of external water supplied to the reactor.

To solve this problem, a reactor is proposed for producing a chlorine dioxide solution, including three flow chambers arranged vertically in succession, separated by partitions with through channels, with pipes for draining an aqueous solution of chlorine dioxide in the upper chamber and pipes for supplying reagents and draining the reaction solution in the lower , with the possibility of placing nozzles, such as Raschig rings, in the middle chamber. The cameras have a rounded shape with a variable curvature of the inner surface, and their volume increases from lower to upper. The partitions are made in the form of a cone surface directed downward with rims at the base in which radial channels are made from the outer edge of the rim to the center. In this case, the lower partition, in comparison with the upper one, is characterized by a smaller diameter and a greater rim height, a large length and cross-sectional area of the radial channels with a smaller number of them.

A tube is located along the axis of the reactor for connecting the chamber to the external environment.

The nozzles for supplying reagents are located in the conical part of the lower chamber and are directed tangentially to each other with an offset relative to the center of the chamber.

The shape of the reactor chambers provides a directed flow of the gas-liquid medium from the bottom up and eliminates the appearance of stagnant zones, primarily zones of accumulation of gaseous chlorine dioxide.

An increase in the volume of the reactor chambers from the lower to the upper, as well as an increase in the total volume of the radial channels from the lower partition to the upper, increases the removal of chlorine dioxide from the lower chamber and reduces its concentration in the aqueous solution. The movement of gas and liquid components along radial channels and their transition to the middle and upper chambers is accompanied by dispersion of gas and liquid, their mixing, uniform distribution and equalization of their concentration in the volume of the liquid mixture.

The intake of air from the external environment into the lower chamber, carried out using a tube with an adjustable plug, and due to the small rarefaction created by the ejector in the reactor, contributes to the additional dispersion of the resulting gases, their distribution in the volume of the liquid phase in the chambers, and the improvement of their removal.

The tangential arrangement of the reactant supply pipes leads to the flow of reactant feeds entering the liquid solution, where they are slightly diluted, sufficient to slightly reduce the rate of the fast reaction of chlorine dioxide formation and necessary to reduce its local accumulation with a high concentration and increasing the possibility of decomposition (self-decay).

The description of the reactor for obtaining a solution of chlorine dioxide in water, characterized by signs identical to all the signs of the proposed solution, was not found in the sources of information. The proposed reactor differs from the selected prototype in the form of chambers and partitions between them, the location of the nozzles for supplying reagents and the presence of a tube with an adjustable plug for supplying air from the external environment to its lower chamber. This allows us to conclude that the proposed solution meets the criterion of "novelty."

The achievement of the specified technical result is possible only when using all the essential features of the proposed technical solution in the aggregate, which ensures compliance with its criterion of "inventive step".

Figure 1 presents the reactor to obtain a solution of chlorine dioxide (front view in section).

Figure 2 presents the partition of the reactor chambers (bottom view).

Figure 3 presents the lower chamber of the reactor (top view with section).

The reactor includes a housing 1 with three round-shaped chambers with a variable curvature of the inner surface, lower 2, middle 3 and upper 4. On the vertical guide 5 located along the axis of the reactor, partitions 6 and 7 are installed, separating chambers 2-3 and 3-4. The partitions are made in the form of a cone surface with rims 8 at the base and are mounted with the top of the cone down. Radial channels 9 are made in the rims from the outer edge of the rim to the center, alternating with guides 10. At the interface of the chambers, partitions 6 and 7 are supported by guides 10 on the rim edge on the walls of chambers 3 and 4, while the radial channels 9 provide passage for gas and liquid from the lower chamber to the upper. In the guide 5 along the vertical axis is a tube 11 with an adjustable plug 12 for connecting the camera 2 with the external environment. In chamber 2, nozzles 13 and 14 are tangentially located for supplying reagents and nozzle 15 for draining the reaction solution. In the upper part of the housing 1 is located a pipe 16 for draining an aqueous solution of chlorine dioxide.

The internal (working) height of the reactor is 37 cm, and taking into account technological equipment, the external height reaches 52 cm. The maximum internal diameter of the largest chamber 4 is 17 cm.

The process of obtaining an aqueous solution of chlorine dioxide using the proposed reactor is as follows.

An aqueous solution of sodium chlorate with hydrogen peroxide and sulfuric acid through the nozzles 13 and 14 enter the chamber 2, drain, due to the high density of the reagents, in the conical shape of the lower part of the chamber and concentrate at the bottom, which accordingly increases the reaction rate between them. The reaction product - gaseous chlorine dioxide - rises to the baffle 6, enters the radial channels 9, along them goes to the rim 8 and passes into the chamber 3. Simultaneously with the gas, a liquid mixture enters the chamber 3, consisting of water formed during the reaction and not completely reacted aqueous reagent solutions. In the process of movement of the resulting gas and liquid components along the radial channels 9 and their transition from chamber 2 to chamber 3, gas and liquid are dispersed and mixed. These processes and a decrease in the concentration of reaction components lead to a slight decrease in the rate of gas formation reaction when the gas-liquid medium enters the chamber 3. The gaseous reaction products after filling the chamber 3 through the radial channels 9 of the partition 7 enter the chamber 4. This also disperses the components, but to more fine fractions, due to the smaller geometrical section of the radial channels 9 of the rim 8 of the septum 7 compared to the septum 6. Accordingly, a more uniform mixing occurs vanie and distribution environments. The intake of external air through the tube 11 and its flow through the chamber 2 due to the small 90-95 KPa of vacuum generated by the ejector in the reactor contributes to the additional dispersion of the resulting gas, its distribution in the volume of the liquid phase in the chambers, and the improvement of the discharge of the solution through the pipe 16. To supply the resulting aqueous solution chlorine dioxide from the chamber 4 to the pipe 16 and to the network water using a water-jet ejector. The flow rate of water passing through the ejector, necessary in the production of 1.5 kg / h of chlorine dioxide (6.5 g / h per 1 cm ^{2 of} the cross-sectional area of the larger chamber 4), is 800-900 l / h. The rarefaction in the mixing chamber of the ejector due to the passage of a stream of water through it leads to saturation of the passing water with a solution of chlorine dioxide. After mixing, the resulting mixture enters the mains water supply network.

The advantages of the proposed reactor compared with the prototype 1. With a relatively small size of the reactor (internal height - 37 cm, the inner diameter of the largest chamber - 17 cm), the chlorine dioxide productivity of the reactor reaches 1500 g / h or 6.5 g / h per 1 cm ² cross-sectional areas.

2. The reactor provides a uniform distribution of the gas phase in the finished liquid solution without the use of moving elements and nodes.

3. The reactor requires a relatively small flow rate of water (800-900 l / h with a maximum productivity of chlorine dioxide of 1500 g / h and less water consumption at a lower capacity).

Claims (3)

1. A reactor for producing a solution of chlorine dioxide, including three flow chambers, arranged successively vertically, separated by partitions having the shape of a cone surface directed downward with holes made on the outer edge of the partition, with nozzles for supplying water and draining an aqueous solution of chlorine dioxide in the upper chamber and nozzles for supplying reagents and draining the reaction solution in the lower chamber, with the possibility of placing nozzles, for example Rashig rings, in the middle chamber, characterized in that the chambers have a circular shape with a variable curvature of the inner surface, their volume increases from lower to upper, the partitions are made in the form of a cone surface with rims at the base, and radial channels are made in the rims from its outer edge to the center, while the lower partition, compared to the upper, characterized by a smaller diameter and a larger rim height, a large length and cross-sectional area of radial channels with a smaller number of them. 2. The reactor according to claim 1, characterized in that along its axis there is a tube with an adjustable plug for connecting the camera with the external environment. 3. The reactor according to claim 1, characterized in that the nozzles for supplying reagents are located in the conical part of the lower chamber and are directed tangentially to each other with an offset relative to the center of the chamber.

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