The method of processing fibrous mass of a chemical reagent and device for its implementation

 

(57) Abstract:

The inventive method of processing fibrous mass of a chemical reagent involves feeding into the mixing chamber of the fibrous mass and high concentrations of gaseous transport agent, a feed mixture and a chemical reagent in a flow-through tubular reactor followed by its accumulation in the cell accumulation of the processed fiber material. The mixture of the fibrous mass and gaseous transport agent is served in a flow-through tubular reactor made in the form of spirals> wound on the camera the accumulation of processed fibrous mass, the ratio of pipe diameter flow-through tubular reactor to the diameter of its coils, equal to 1:18-1:60. A chemical reagent is served directly in the flow-through tubular reactor through nozzles located along the length of the tubular flow reactor. Processing the resulting reaction mass is carried out in the past in the turbulent regime of the motion of a flow rate of 1 to 50 m/s Installation for processing fibrous mass of a chemical reagent contains a chamber for loading a fibrous mass of high concentration, the mixing chamber the pulp with gaseous transport is, the United States on the entrance with the camera offset, and at its output with camera accumulation of processed fibrous mass, means for entering a chemical reagent. Flow-through tubular reactor made in the form of a spiral, wound on camera accumulation of processed fibrous mass, the ratio of the diameter of the pipe reactor to the diameter of its coils, equal to 1:18 to 1:60. 2 s and 5 C.p. f-crystals, 2 Il.

The invention relates to a method of processing fibrous mass of a chemical reagent and installation for its implementation and can be used in the pulp and paper industry for processing pulp bleaching reagent.

Currently, the processing of the fibrous mass, in particular cellulose fiber and pulp, chemicals carried out in various ways. Known processes for the treatment of cellulosic fibrous mass of gaseous chlorine in suspension [1, 2]. The known process of chlorination of cellulose or similar mass in the column-absorber [3]. Known processes of bleaching fibrous mass of gaseous chemicals, including ozone, oxygen, chlorine, tower type reactor [4]. Known methods of processing fibrous pulp with gaseous reagents is P CLASS="ptx2">

However, all these methods are characterized by the lack of mass transfer in the reaction zone, the low utilization rate of the reagent, the lack of quality of the processed product. Used in these processes do not allow concentrated fibrous mass and is characterized by high intensity and complexity of service.

Closest to the proposed method is a method of processing fibrous material with gaseous reagent in the jet reactor, which to some extent overcomes the above disadvantages [6]. The known method can be used in the bleaching process of pulp with gaseous reagent. The method provides for the supply of fibrous material with a concentration of 15% and above on absolutely dry matter through the chamber for loading into the mixing chamber with a gaseous reagent, followed by applying the resulting reaction mixture in the jet reactor, connected to the output chamber of the accumulation of the processed fiber material. The main disadvantage of this method is that it does not provide sufficiently intense mass transfer in the reaction zone and the uniform distribution is the low quality of the processed pulp (degree of whiteness does not exceed 55%).

The invention is directed to create a highly efficient method of processing fibrous mass of a chemical reagent that provides a uniform treatment of the material throughout the volume of the layer of the reaction mass, reduced reagent consumption, high quality of the processed fibrous mass (in particular, the increase of the degree of whiteness of the pulp), the possibility of processing fibrous mass of high concentration with the use of various chemical agents, both in gaseous and in liquid state.

The problem is solved by pre-mixing the fibrous mass is a high concentration of gaseous transport agent in the camera displacement with subsequent supply of the mixture flowing in a tubular reactor made in the form of a spiral wound upon a chamber for accumulation of processed fibrous mass, the ratio of pipe diameter flow-through tubular reactor to the diameter of its coils is 1:18 - 1:60 when this chemical reagent is fed directly into the reactor through nozzles located along the length of the flow-through tubular reactor, and the treatment is carried out in a turbulent mode of motion with the velocity of flow of the reaction mixture in the reactor 1 to 50 m/s

Pregnacy the reactor through distributed over the length of the nozzle and the treatment is carried out in a turbulent mode of motion with the velocity of flow of the reaction mixture in the reactor 1 - 50 m/s When flow-through tubular reactor made in the form of a spiral, twisted on the camera the accumulation of processed fibrous mass, the ratio of pipe diameter flow-through tubular reactor to the diameter of its round 1:18 - 1:60.

The process of processing fibrous mass of high concentration in a turbulent flow of the reaction mixture moving in the reactor with a flow rate of 1 to 50 m/s, allows significantly intensify mass transfer processes in the reaction zone. Turbulent flow of the reaction mixture in the tubular flow reactor is provided in the claimed range of velocity of its movement and at the stated ratio of the diameters of the pipe flow tubular reactor and its coils. Supply of chemical reagent directly into the flow-through tubular reactor through nozzles located along the length of the tubular flow reactor, promotes uniform processing of the fibrous material throughout the volume of the layer of the reaction mixture, and further stirring the reaction mixture. Fibrous mass, partially dispersed by the flow of gaseous transport agent in the mixing chamber, moving a flow rate of 1 to 50 m/s in the reactor, made further dispersion forces, acting on the flow from the side walls of the tubular flow reactor. This additional bundle of fibers increases the reaction surface, which in turn leads to almost 100% use of chemical reagent. Analysis of the reaction mixture at the outlet of the flow-through tubular reactor shows the absence in it of a chemical reagent. Execution flow tubular reactor in the form of a spiral, wound on camera accumulation, provides compactness of installation and reduction of production space.

The necessary degree of mixing and dispersing fibrous mass of high concentration, and as a result, the high efficiency of the processing chemical reagent, is achieved in the stated values of the speed of the reaction stream in a flow tube reactor (1 to 50 m/s) and the ratio of diameters of pipe flow tubular reactor and its orbit (1: 18-60). When the flow of the reaction mass with velocity less than 1 m/s are unstable machining conditions, the movement of the reaction mass becomes predominantly pulsating character, as a consequence, reduced all the process indicators - degree white is m costs. The reduction in the stated ratio of pipe diameter flow-through tubular reactor to the diameter of its turn leads to unstable flow tubular reactor, increasing the specified ratio sharply decreases the quality of the processed product.

In the proposed method the fibrous mass high concentrations of pre-mixed with gaseous transport agent.

Most preferably, the mixing mass ratio of the fibrous mass transport of the gaseous agent, equal to 10-60:1. If you increase the specified ratio above 60:1 possible emergency situation caused by the clogging of flow tubular reactor, and the reduction ratio below 10:1 is not economically feasible.

Used in the process of a chemical reagent can be a gas, such as oxygen, ozone or chlorine and liquid, for example an aqueous solution of chlorine dioxide or hydrogen peroxide.

If chemical reactant is a gaseous substance, it can be used as gaseous transport agent. In this case, part of the gaseous chemical reactant is fed to the mixing chamber as transport is gaseous chemical reactant is fed directly into the flow-through tubular reactor through a special nozzle, located along its length.

As the transport of the gaseous agent, you can use air or superheated steam. Often the air is used as the transport gaseous agent in the processing of fibrous mass aqueous solution of oxidizer.

The method allows to handle highly concentrated fibrous mass with a concentration of absolutely dry matter 35 to 90 wt.%.

In Fig. 1 shows a diagram of the installation for processing fibrous mass of a chemical reagent; Fig. 2 shows a device for feeding fibrous mass, the mixing chamber and means for entering the transport of the gaseous reactant.

The installation includes the camera offset 1 fibrous mass and gaseous transport agent having the device 2 for loading a fibrous mass and the tool 3 to enter the transport of gaseous agent, which may be in the form of the feeding pipe connected to the inlet with the mixing chamber flow-through tubular reactor 4 made in the form of a spiral wound upon a chamber for the accumulation of 5-treated fibrous mass. The ratio of pipe diameter flow-through tubular reactor to the diameter of its coils is 1: 18 - 1:60. Protocatechualdehyde 5 is connected to the output of the flow-through tubular reactor and a device 7 for pumping the treated mass and a means 8 for exhaust gas.

To download fibrous mass in the mixing chamber 1 using the known device, which consists of a hopper 9, the screw 10 is enclosed in a casing 11, which is provided with perforations 12 to displace gas from the fibrous mass, and the check valve 13.

Specific dimensions and materials of the individual components of the installation are determined by the form of a fibrous mass and chemical conditions of handling and speed of reaction.

The method is as follows.

Fibrous mass impregnated by reaction liquid (e.g. aqueous alkali solution) is fed into the hopper 9 of the device 2 for loading a fibrous mass where the screw 10 of the fibrous mass is fed to the output device, where it is compacted in the "stock tube". In the process of education "massin tube" from it displaces air through the holes of the perforation 12 is output from the device 2 for loading a fibrous mass. Education "massin tube" is accompanied by increased pressure on the check valve 13. As soon as this pressure becomes higher than the pressure in the mixing chamber 1, the check valve 13 is opened and a portion of the fibrous mass gets into the camera offset 1. Gaseous transport agent supplied is soobrazhayu transport agent serves in a mass ratio of the fibrous mass: gas transport agent, equal to 10 to 60:1. From the camera offset 1 fibrous mass, broken down into individual fibers, is transported by the flow of gaseous transport agent in a flow-through tubular reactor 4, which is made in the form of a spiral wound upon accumulation chamber 5, when the ratio of pipe diameter flow-through tubular reactor to the diameter of its coils, equal to 1: 18 to 1:60. A chemical reagent is served directly in the flow-through tubular reactor through nozzle 6 for supplying a chemical agent located along its length. The feed rate to the reactor a mixture of pulp with gaseous transport agent and the feed rate in a flow tube reactor chemical reagent regulate so that the speed of flow of the reaction mass in the reactor was 1 - 50 m/s Treated reaction mass is transported in the accumulation chamber 5. In case of carrying out the process of pulp bleaching Luggage accumulation is a tower high concentrations, where the treated mass accumulate and pumped through the device 7 for further processing and pumping the treated mass provided the technological requirements of production, and the exhaust gas through the means 8 for illustreret the following examples.

Example 1. Pulp mass, wrung to the content of absolutely dry matter 30 wt.% and soaked in the reaction liquid (aqueous alkali solution), processed bleaching reagent. The content of lignin in the original product in the Kapp is 30. The treatment is carried out under the following conditions. The bleaching reagent is oxygen. As the transport of the gaseous agent, a mixture of oxygen and air. The mass ratio of the cellulose mass transport of the gaseous agent is 20:1. Processing time 3 minutes, the Speed of flow of the reaction mixture in the tubular flow reactor of 1.33 m/s, the Ratio of pipe diameter flow-through tubular reactor to the diameter of its round 1:26. Reactor pressure of 1 kg/cm2. The temperature of the reaction medium 60oC. the Treatment is carried out in accordance with the above method. After processing, the content of lignin in the pulp mass in units of Kappa is 15. The consumption of chemical reagent 19,7 kg per tonne of pulp. Analysis of the treated pulp at the outlet of the flow-through tubular reactor showed almost complete absence of a bleaching agent in its composition.

Example 2. The pulp mass is car Ried out under the following conditions. The bleaching reagent in 1.5% aqueous solution of hydrogen peroxide. As the transport of gaseous agent used air. The mass ratio of the cellulose mass transport of the gaseous agent is 20:1. Processing time 3 minutes, the Speed of flow of the reaction mixture in the tubular flow reactor of 1.33 m/s, the Ratio of pipe diameter flow-through tubular reactor to the diameter of its round 1:26. The pressure in the flow-through tubular reactor of 1 kg/cm2. The temperature of the reaction medium 60oC. the Treatment is carried out in accordance with the above method. After processing, the content of lignin in the pulp mass in the Kapp was 12. The consumption of chemical reagent 12 kg per tonne of pulp. Analysis of the treated pulp at the outlet of the flow-through tubular reactor showed almost complete absence of a bleaching agent in its composition.

For comparison with similar bleaching of cellulosic fibrous mass in a known manner [6] the lignin content in the treated pulp mass in units of Kappa is 27. At the exit of the reactor is observed leakage of the bleaching reagent. The degree of use of the reagent does not exceed 15%.

Ka is the first high mass concentration of a chemical reagent, namely, to reduce the consumption of chemical reagent and improve the quality of the processed fiber material at the expense of intensifitsirovany mass transfer processes and uniform distribution of the chemical throughout the volume of the layer of the reaction mass. Method and installation according to the invention is developed for its implementation, allow for processing fibrous mass of high concentration with the use of a chemical reagent in gaseous and liquid state, and the design flow tubular reactor significantly reduces its intensity and production areas.

1. The method of processing fibrous mass of a chemical reagent, comprising feeding into the mixing chamber of the fibrous mass and high concentrations of gaseous transport agent, a feed mixture and a chemical reagent in a flow-through tubular reactor followed by its accumulation in the cell accumulation of the processed fiber material, characterized in that the mixture of the fibrous mass and gaseous transport agent is served in a flow-through tubular reactor made in the form of a spiral, wound on camera accumulate processed politicheskii reagent is served directly in the flow-through tubular reactor through the nozzle, located along the length of the tubular flow reactor, and processing the resulting reaction mass is carried out in the past in the turbulent regime of the motion of a flow rate of 1 to 50 m/s

2. The method according to p. 1, characterized in that the fiber is mixed with gaseous transport agent in a mass ratio of 10 60 1.

3. The method according to PP. 1 and 2, wherein the chemical reactant is a gaseous reagent such as ozone, oxygen or chlorine.

4. The method according to p. 3, characterized in that the chemical gaseous reagent is simultaneously used as the transport agent.

5. The method according to PP. 1 and 2, wherein the chemical reagent is an aqueous solution, for example, hydrogen peroxide or chlorine dioxide.

6. The method according to p. 5, characterized in that the gaseous transport agent is air or superheated steam.

7. Installation for processing fibrous mass of a chemical reagent containing chamber for loading a fibrous mass of high concentration, the mixing chamber the pulp with gaseous transport agent, provided with a means for entering gaseous transport agent, running trobc the Oh fibrous mass, means for entering a chemical reagent, characterized in that the flow-through tubular reactor made in the form of a spiral, wound on camera accumulation of processed fibrous mass, the ratio of pipe diameter flow-through tubular reactor and the diameter of its coils 1 18 1 60, and a means for input of chemical reagent in the form of nozzles located along the length of the tubular flow reactor.

 

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