RU2291831C1 - Method of pneumatic transportation of powder-like oxiddizer - Google Patents

Abstract

FIELD: material handling facilities; pneumatic transportation.

SUBSTANCE: according to invention, tightness of pneumatic transportation plant is checked before starting and periodically in process of operation by creating vacuum gauge pressure of at least 0.08 MPa in pipeline and air line by vacuum pump, and residual pressure not higher than 0.02 MPa in unloader with subsequent revealing degree of air suction after closing of evacuation line. Reduction of vacuum gauge pressure in 10 min in pipeline should not exceed 0.005 MPa and in air line, not exceed 0.02 Mpa and rise of residual pressure in unloader should not exceed 0.0025 MPa in 5 min.

EFFECT: provision of reliable tightness of system and drying the system before starting and in process of operation.

3 cl, 1 tbl, 4 dwg

Description

The invention relates to the field of pneumatic transportation of powdered materials. It can be used in many industries.

Pneumatic conveying units are widely used for transporting powdered materials. Pneumatic transportation is also used in the production of mixed solid rocket fuel (STRT) for interfacial transfer of a powdered oxidizer. Powdered oxidizing agent (PO) is used as a mixture of fractions without additives or with the introduction of additional components (AML). A description of the applied pneumatic conveying schemes and equipment is given in the book of the author J. Urban "Pneumatic Transport", Mechanical Engineering, Moscow, 1967. Both in this book and in numerous patent sources and technical literature, the main attention is paid to the ways of feeding the pipeline with transported material and the process transportation.

A known method of pneumatic transportation of a powdery oxidizing agent with additives, comprising supplying dried compressed air with a moisture content of 0.8 g / m ³ to an air chamber with controlled temperature and pressure, followed by air passing through the pipeline to the unloader, cyclones, air duct, wet filter when sucked by a vacuum pump (RF patent 2202507 from 04/20/2003, adopted as a prototype - figure 1).

In this method, the distinguishing features mainly relate to the preliminary preparation of the transported AML and the modes of transportation. However, in view of the specific requirements for software and AML regarding the preservation of their physicochemical properties, as well as ensuring stable uninterrupted operation for the operation of subsequent operations for the production of STRT, very stringent requirements are imposed on the pneumatic transport installation.

These include: maintaining a constant concentration of air mixture, eliminating air leakage, inadmissibility of traces of moisture on the inner walls of equipment and transport communications.

The prototype shows only a method for checking the tightness of the entire installation as a whole, which is not enough.

Pneumatic installation consists of a number of interconnected pipelines and air ducts. Therefore, special attention should be paid to ensuring reliable tightness of all parts of the pneumatic conveying system before starting and during operation.

The technical task of this invention is to ensure reliable tightness, performing operations on drying the system of the pneumatic conveying system.

The technical result is achieved due to the fact that the dried compressed air with adjustable temperature and pressure with a moisture content of 0.8 g / m ^{3 is} fed into the aero chamber with the subsequent passage of air through the pipeline to the unloader, cyclones, air duct, wet filter when sucked by a vacuum pump. At the same time, before starting and periodically during operation of the pneumatic conveying installation, the tightness is checked by creating a vacuum pump in the pipeline and the air duct of a vacuum pressure of not less than 0.08 MPa, in the unloader of residual pressure not more than 0.02 MPa, followed by determining the degree of air suction after closing the line evacuation, while the decrease in vacuum pressure should be no more than 0.005 MPa in the pipeline in 10 minutes, not more than 0.02 MPa in the air pipe, and an increase in the residual pressure in the discharge barely less than 0.0025 MPa for 5 minutes.

Before putting into operation and before starting the transportation of software and AML, the pipeline is purged with disconnected from the unloader and connected to the cyclone by drained compressed air with a moisture content of not more than 0.8 g / m ³ and a pressure of 0.25 to 0.35 MPa (from 2.5 to 3.5 kgf / cm ²⁾ for at least 2 ^hours.

Before starting the transportation of software and AML, the pipeline is purged through the unloader and cyclone with the outlet to the atmosphere with compressed, dried air at the same parameters heated to a temperature of from 20 to 40 ° C and from 40 to 60 ° C at an ambient temperature, respectively, higher and lower - 20 ° C for 2.5 to 3.5 hours, as well as the entire pneumatic conveying system with the vacuum pump on for 1.5 hours.

Before starting and periodically during operation of the pneumatic conveying installation, the air tightness of the main apparatus, pipeline, air duct of the pneumatic conveying installation is checked for leaks with standardizing indicators for vacuum or residual pressure.

The parameters for checking the tightness of the installation nodes are shown in the table.

Table Node name The created pressure, MPa (kgf / cm ² ) Permissible reduction of vacuum pressure, MPa (kgf / cm ² ) Permissible increase in residual pressure, MPa (kgf / cm ² ) Inspection period Vacuum Residual Pipeline Not less than 0.08 (0.8) - Not more than 0.005 (0.05) for 10 minutes - At least once a month Duct including cyclone and wet filter Not less than 0.08 (0.8) - Not more than 0.02 (0.2) for 10 minutes - At least once every 6 months Unloader including return device - Not more than 0.02 (0.2) - Not more than 0.0025 (0.025) for 5 min At least once a year

The essence of the invention is illustrated by the following drawings.

Figure 1 shows the technological scheme of a pneumatic transport installation, adopted as a prototype.

1 - unloading device;

2 - bootloader;

3 - gateway feeder;

4 - wiper;

5 - aerial cameras;

6 - pipeline;

7 - unloader;

8, 10, 15 - cyclones;

9 - a lock lock;

11 - air duct;

12 - check valve;

13 - a vacuum pump;

14 - container;

16 - wet filter.

Figure 2 shows a diagram for implementing a method of checking the tightness of the pipeline.

4 - wiper;

5 - aerial cameras;

6 - pipeline;

7 - unloader;

11 - air duct;

17 - pipe;

18 - valve;

19 - a vacuum gauge.

Figure 3 shows a diagram for implementing a method of checking the tightness of the air duct.

8 - cyclone;

11 - air duct;

12 - check valve;

13 - a vacuum pump;

16 - wet filter;

18 - valve;

19 - a vacuum gauge;

20 - a stub.

Figure 4 shows a diagram for implementing a method of checking the tightness of the unloader.

7 - unloader;

8 - cyclone;

11 - air duct;

18 - valve;

19 - a vacuum gauge;

21 - unloading hatch of the unloader;

22 - inlet pipe of the unloader.

The following describes a method for checking the tightness of individual devices. To check the tightness (figure 2) of the pipeline disconnect it from the air chamber 5 and drown. The pipeline 6 is disconnected from the unloader 7 and an insert is connected to it, consisting of a pipe 17, a valve 18, a wiper apparatus 4 and a vacuum gauge 19, and an air pipe 11 with a vacuum pump is connected to the other end of the insert. A vacuum pressure of at least 0.08 MPa (0.8 kgf / cm ² ) is created in the system, closed with valve 18, and a drop in vacuum pressure is recorded on the vacuum gauge 19, which should be no more than 0.005 MPa (0.05 kgf / cm ² ) in for 10 minutes.

To check the tightness of the air duct 11 (Fig. 3), disconnect it from the cyclone 8 of the return and ON device and plug it with a plug 20. Between the vacuum pump 13 and the check valve 12, an insert with a valve 18 and a vacuum gauge 19 is installed. By turning on the vacuum pump, a vacuum is created in the system up to vacuum pressure of at least 0.08 MPa (0.8 kgf / cm ² ) and shut off the valve. Watch for a decrease in vacuum pressure, which should not exceed 0.02 MPa (0.2 kgf / cm ² ) for 10 minutes. The air tightness test is carried out before filling the wet filter 16 with water.

To check the tightness of the unloader 7 (Fig. 4), its unloading hatch 21 and inlet pipe 22 are plugged, an insert with a valve 18 and a vacuum gauge 19 is connected to the outlet pipe of the cyclone 8 of the device for returning software and AM, the free end of the insert is connected to line 11 with a vacuum pump . When the vacuum pump is turned on, a residual pressure of not more than 0.02 MPa (0.2 kgf / cm ² ) is created in the system and the valve is closed. They monitor the increase in residual pressure, which should be no more than 0.0025 MPa (0.025 kgf / cm ² ) for 5 minutes.

In the further operation process, a periodic tightness check of the indicated nodes of the pneumatic transport installation is carried out: the pipeline after each disassembly, but at least once every three months, the air duct after each disassembly, but at least once every six months, the unloader at least once a year.

The technological complex for the production of STRT is launched into the continuous production of STRT for up to 24 days, after which the unit is completely cleaned and prepared for the next launch. At the same time, cleaning and preparation of the pneumatic conveying installation as an integral part of the technological complex is carried out in the following order.

Before starting and during operation, before each start-up of the pneumatic conveying installation, the pipeline 6 is connected on one side to the air chamber 5, and on the other hand, bypassing the unloader 7, to the air exhaust line through the cyclone 15. Turn on the supply of compressed dried air to the air chamber 5 with an absolute moisture content of not more than 0.8 g / m ³ at a set pressure of 0.25 MPa (2.5 kgf / cm ² ) to 0.35 MPa (3.5 kgf / cm ² ) and purge for at least 2 ^x hours.

Then, the pipeline 6 and the line of air outlet to the atmosphere are connected to the unloader and through it purging with compressed, dried air at the same parameters is continued for 2.5 to 3.5 hours. In this case, the air is heated to a temperature of from 20 to 40 ° C and from 40 to 60 ° C at an ambient temperature (outdoors), respectively, above and below -20 ° C.

Next, turn on the vacuum pump 13 and purge is continued at the above air parameters for at least 1.5 hours. At the same time, air passes through the entire system of the pneumatic conveying system from the air chamber 5 to the vacuum pump 13, after which it is discharged into the atmosphere. When the vacuum pump 13 is turned on, the valve 12 in the line for discharging air into the atmosphere closes due to vacuum, and when purging with the vacuum pump not working, it opens due to excess pressure.

The need for drying the pneumatic conveying system is due to the fact that in the presence of traces of moisture on the walls of the apparatus, pipeline, air duct, an oxidizing agent sticks. This leads to a violation of normal modes of transportation until the blockage of the line with the subsequent stop of the process.

To check the tightness of the pneumatic conveying installation, in general, disconnect the pipeline 6 from the air chamber 5 and shut off, turn on the vacuum pump. In this case, the vacuum pressure in the line in front of the vacuum pump must be at least 0.08 MPa (0.8 kgf / cm ² ). Upon receipt of satisfactory results, the pipeline 6 is connected to the air chamber 5 and the pneumatic transport unit is ready for transportation of software and AML in the manufacturing process of the STRT.

The method of pneumatic transportation of the oxidizing agent with the implementation of the features of the invention was tested with positive results at the Federal State Unitary Enterprise Perm Plant named after S.M. Kirov.

Claims (3)

1. The method of pneumatic transportation of a powdery oxidizing agent, comprising supplying dried compressed air with temperature and pressure with a moisture content of 0.8 g / m ³ to the air chamber, followed by air passing through the pipeline to the unloader, cyclones, air duct, wet filter when sucked by a vacuum pump, characterized in that before starting and periodically during operation of the pneumatic conveying installation, the tightness is checked by creating a vacuum pump in the pipeline and air duct vacuum pressure not less than 0.08 MPa, in the residual pressure unloader not more than 0.02 MPa, with subsequent determination of the degree of air suction after closing the vacuum line, while the decrease in vacuum pressure should be no more than 0.005 MPa in the pipeline for 10 minutes, in the air pipe - not more than 0.02 MPa, and the increase in residual pressure in the unloader is not more than 0.0025 MPa for 5 minutes 2. The method according to claim 1, characterized in that before putting into operation and before each start-up of the pneumatic conveying installation, the pipeline is dried by supplying compressed dried air with a moisture content of not more than 0.8 g / m ³ and pressure from 0.25 to 0.35 MPa for at least 2 hours, bypassing the unloader, and venting to the atmosphere, and then purging is continued through the unloader also by venting to the atmosphere for 2.5 to 3.5 hours by supplying hot air with a temperature of from 20 to 40 and from 40 to 60 ° C at an ambient temperature respectively higher and below -20 ° C. 3. The method according to claim 2, characterized in that in addition the entire system from the aerial camera to the vacuum pump is purged with dried compressed air with the same parameters of the latter and with the vacuum pump turned on for at least 1.5 hours

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