JP2015218981A - Method and device for removing deposit in water tube boiler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and a device for removing deposit in a water tube boiler capable of efficiently realizing peeling of the deposit bonded to the water tube to be cleaned by a less-expensive and simple configuration even if an inside segment of the water tube boiler is complicated and narrow.SOLUTION: This invention relates to a method for removing deposit in a water tube boiler to clean an outer surface of the water tube by injecting a compressed cleaning substance into the water tube boiler. This invention has a configuration comprising a cleaning machine main body for mixing dry ice with compressed air and a nozzle segment for spraying the cleaning substance of mixture gas of dry ice and compressed air manufactured by the cleaning machine main body on the outer surface of the water tube with an extended pipe and the injection nozzle so as to peel off the deposit bonded to the outer surface of the water tube.

Description

  The present invention relates to a technique for removing deposits adhering to an outer surface of a water pipe in a water pipe boiler. More specifically, the present invention relates to a technique of spraying dry ice on deposits adhering to the outer surface of a water tube in a water tube boiler, and separating and removing the deposits.

  Generally, in order to remove deposits (such as combustion ash containing sulfur) attached to the outer surface of the water tube in the water tube boiler, water, chemicals, etc. are poured into a container such as a boiler tube with a built-in water tube to form a pool. “Pool construction method” for eluting deposits (Patent Document 1), “Liquid spraying method” for peeling and removing deposits by spraying pressure liquid or microbubbles composed of water, chemicals, dry ice, etc. on the outer surface of water pipe ( Patent Documents 2 and 3) have been performed.

  Further, for the removal of deposits attached to general structures or the like that are not water pipes, a “dry ice method” (Non-patent Document 1) in which dry ice is sprayed to remove deposits is performed.

Patent Document 1 based on the “Pool Method” includes a step 1 in which an object to remove sludge is immersed in a cleaning liquid, a step 2 in which the temperature and pressure of the cleaning liquid are changed to generate bubbles in the cleaning liquid, and a temperature increase. A method of physicochemical cleaning of deposited sludge comprising step 3 of promoting sludge removal is disclosed. In this case, in Step 2, at least one selected from the group consisting of gaseous nitrogen, liquid nitrogen, and dry ice is injected into the cleaning liquid to change the temperature and pressure to generate bubbles.

  Since this method is based on the premise that the object to be removed of sludge is immersed in the cleaning liquid, it becomes a very large-scale cleaning, and it is necessary to cope with the waste liquid treatment of the cleaning liquid. As a result, the equipment cost becomes high. Furthermore, since it is required to have a watertight structure for immersing in the cleaning liquid, it is necessary to have an equipment configuration that considers cleaning in advance.

  In Patent Document 2 based on the “liquid spraying method”, a plurality of guide pipes are provided in a heat transfer tube group provided in a boiler combustion chamber, a cleaning pipe is inserted into the guide pipe, and cleaning water is injected from the cleaning pipe. This cleans the outer surface of the heat transfer tube group.

  This method requires a cleaning mechanism incorporated in the apparatus from the new installation stage of the boiler, and the equipment becomes complicated and expensive. Moreover, since the position where the cleaning water is jetted from the cleaning pipe is fixed, the position where cleaning can be performed is limited. A lot of deposits in the water pipe boiler are generated around the connection portion of the water pipe connected to the water drum, so that a situation where the removal of the deposits is not ideal occurs.

  Furthermore, since the cleaning mechanism is built into the boiler combustion chamber, the amount of deposits to be attached becomes more complex than that of the boiler combustion chamber having only a water pipe.

  Patent Document 3 is provided with a water pipe cleaning device relative to a heat transfer tube group in a boiler combustion chamber, injecting cleaning water from the water pipe cleaning device, and removing deposits on the outer surface of the heat transfer tube group. A plurality of groups and water pipe cleaning devices are provided opposite to each other.

This method requires a water pipe cleaning device incorporated in the apparatus from the new installation stage of the boiler, and the equipment becomes complicated and expensive. Moreover, since the position where the cleaning water is jetted from the water pipe cleaning device is fixed, the cleaning range is limited. A lot of deposits in the water pipe boiler are generated around the connection portion of the water pipe connected to the water drum.

  On the other hand, Non-Patent Document 1 uses heat shrinkage and volume expansion by mixing dry ice pellets with compressed air and spraying from a spray nozzle as a method for removing deposits adhering to general structures, A method for peeling off deposits adhering to an object to be cleaned is disclosed.

  However, this technology is very effective in peeling off deposits attached to objects to be cleaned in an open space, but in a water tube boiler, the arrangement of water tubes is complicated and narrow. The deposit adhering to the object to be cleaned could not be peeled off, resulting in a superficial cleaning, and an effective cleaning could not be realized.

FIG. 5 shows a state in which the outer wall of the water tube boiler of A heavy oil (JIS type 1 No. 1) is removed as a fuel with a rated capacity of 25 t / h, a heat transfer area of 353 m ² , a maximum working pressure of 1.96 MPa, a normal pressure of 1.47 MPa, and a The appearance is shown in b), the plan view in c), and the side view in d). The portion indicated by white square in FIG. 5b) is a connecting portion between the water pipe and the water drum, and is a portion where deposits are easily deposited. Thus, the water pipe part and water drum part of a water pipe boiler have many very narrow parts, and are presenting a complicated situation.

  In this example, the water pipe connected to the water drum is about 1,400 at intervals of 30 mm, and stands upright in one direction, so it is complicated and narrow, and the structure is incapable of entering and leaving the cleaning operator. The workability of peeling and removing the deposited deposit is poor, and it is difficult to peel and remove the deposit efficiently.

  In consideration of the above, even if it is complicated and narrow, it is cheap and has a simple structure, and a deposit removal method and apparatus in a water tube boiler that can efficiently achieve the separation of deposits attached to the water tube that is the object to be cleaned. Was desired.

JP 2012-073247 A JP 2009-085555 A JP 2003-314801 A

"DRY-ICE POWER Dry Ice Cleaning Machine" Greentech Japan Catalog

  In view of the problems described in the prior art, the present invention efficiently removes deposits attached to a water pipe that is an object to be cleaned with an inexpensive and simple structure even if the inside of the water pipe boiler is complicated and narrow. It is an object of the present invention to provide a deposit removal method and apparatus in a water tube boiler that can be well realized.

A first invention of the present invention is a method for removing deposits in a water tube boiler, in which a dry ice in the form of pellets or powder that has been pressurized is injected into the water tube boiler to clean the outer surface of the water tube part. And a cleaning body that mixes dry air and compressed air, and a cleaning body, which is a mixed gas of dry ice and compressed air manufactured by the cleaning body, is sprayed to the outer surface of the water pipe portion by the nozzle portion, It is the deposit removal method in the water pipe boiler which peels the deposited deposit.

  According to a second aspect of the present invention, in addition to the first aspect, the nozzle section includes an extension pipe section connecting a plurality of extension pipes, and compression of dry ice and high pressure in the axial direction of the extension pipe sections. It is the deposit removal method in the water tube boiler comprised with the injection nozzle part which made the direction which the mixed gas with air blows off 30-60 degrees.

  According to a third aspect of the present invention, in addition to the first or second aspect, the extension pipe is configured to freely hold a cap nut with a cylindrical pipe and a fastener at one end of the pipe, and the other end. And a connection screw for connecting to a cap nut of another extension pipe, and one or a plurality of extension pipes are arranged in accordance with the position where the deposit adhered to the outer surface of the water pipe portion is peeled off. This is a method for removing deposits in a water pipe boiler that is connected in combination to form an extension pipe part.

  According to a fourth aspect of the present invention, in addition to the first to third aspects, the dry ice is a method for removing deposits in a water tube boiler in the form of pellets and / or powder.

  According to a fifth aspect of the present invention, there is provided a method for removing deposits in a water tube boiler by spraying pellet-shaped or powder-shaped dry ice to which pressure is applied into the water tube boiler, and cleaning the outer surface of the water tube portion. And a cleaning body that mixes dry air and compressed air, and a cleaning body, which is a mixed gas of dry ice and compressed air manufactured by the cleaning body, is sprayed to the outer surface of the water pipe portion by the nozzle portion, It is the deposit removal apparatus in the water pipe boiler which peels off the deposited deposit.

  According to a sixth aspect of the present invention, in addition to the fifth aspect, the nozzle section includes an extension pipe section connected to a plurality of extension pipes, and compression of dry ice and high pressure with respect to the axial direction of the extension pipe sections. It is the deposit removal apparatus in the water tube boiler comprised with the injection nozzle part which made the direction which the mixed gas with air blows off 30-60 degrees.

  According to a seventh aspect of the present invention, in addition to the fifth to sixth aspects of the present invention, the extension pipe has a cylindrical pipe and a cap nut freely held by one end of the pipe and a second end at the other end. And a fastener for connecting with a cap nut of another extension pipe, and one or a plurality of the extension pipes according to the position where the deposit attached to the outer surface of the water pipe portion is peeled off. It is the deposit removal apparatus in the water pipe boiler which connected and combined as the extension pipe part.

  According to an eighth aspect of the present invention, in addition to the fifth to seventh aspects of the present invention, the dry ice is a deposit removing device in a water tube boiler in the form of pellets and / or powder.

  Here, the mixed gas of dry ice and compressed air sprayed on the object to be cleaned will be described below as a cleaning body.

According to the present invention,
First, even in a narrow part where a cleaning worker cannot enter, a plurality of extension pipes are connected to the injection nozzle part and inserted into the narrow part, and the deposit in the water pipe boiler is ejected by the cleaning body from the nozzle. Removal can be performed accurately and efficiently.

Further, the extension pipe can be easily aligned with the cleaning portion by connecting several kinds of extension pipes in accordance with the position where the deposit is removed. About the nozzle of the injection nozzle part, since the injection direction can be 30 to 60 degrees with respect to the axis of the extension pipe, the cleaning body can be accurately injected in accordance with the cleaning location even in a narrow part. Can do.

  In addition, since the cleaning body is a mixed gas of dry ice and high-pressure compressed air, no residue of the cleaning body remains after cleaning, and no post-treatment of the cleaning body is necessary.

  Moreover, the deposit removal apparatus in the water tube boiler of the present invention can be separated into units of a compressor, a washing machine body, a spray nozzle, an extension pipe, and hoses, and is excellent in portability.

  In general peeling and cleaning of deposits, peeling is not easy even with high-pressure cleaning of about 10 MPa, but in the present invention, since it can be realized with an air pressure of about 1.6 MPa, the capacity of the compressor can be reduced, and The components from the compressor to the nozzle can be made to have a relatively low pressure specification, and inexpensive equipment can be obtained.

  Compared to conventional cleaning methods, the quality and quality of the cleaning of the deposit peeling and cleaning method according to the present invention ensures peeling and cleaning, so that the object to be cleaned is prevented from rusting and depositing. It is possible to prevent deterioration of the object to be cleaned due to corrosion, and to extend the life of the water tube boiler.

  Furthermore, since the conventional technology is a cleaning device built in the water tube boiler, the equipment is large and expensive, but the present invention has a separable configuration and excellent portability, so can do.

It is a figure which shows the outline | summary of a structure of the deposit removal method and apparatus in the water tube boiler of this invention. It is a figure which shows one Example of the extension pipe | tube part of this invention. It is a figure which shows one Example of the injection nozzle part of this invention. It is a figure which shows one Example of the washing | cleaning by the deposit removal method and apparatus in the water tube boiler of this invention. It is a figure which shows the structure of the water tube boiler used as the washing | cleaning object of this invention.

  The method and apparatus for removing deposits in a water tube boiler of the present invention includes a cleaning machine body that mixes dry ice and compressed air, and a cleaning body that is a mixed gas of dry ice and compressed air manufactured by the cleaning machine body. It is set as the structure sprayed on a water pipe part outer surface by a nozzle part, and the deposit adhering to a water pipe part outer surface is peeled.

  The nozzle part includes an extension pipe part connected to a plurality of extension pipes, and an injection nozzle part in which a direction in which a mixed gas of dry ice and high-pressure compressed air is blown out is 30 to 60 degrees with respect to the axial direction of the extension pipe part And consist of

  The high-pressure compressed air has a pressure of about 1.6 MPa and can be manufactured by a general compressor. However, a screw compressor is desirable from the viewpoint of vibration, quality of compressed air, ease of operation such as movement, and the like.

  The extension pipe constituting the nozzle part includes a cylindrical pipe and a fastener for freely holding a cap nut at one end of the pipe by a fastener and connecting the cap nut of another extension tube to the other end. In accordance with the position where the deposit attached to the outer surface of the water pipe part is peeled off, one or more of the extension pipes are connected in combination to form an extension pipe part, and the outer surface of the water pipe part The deposit adhering to is peeled off.

  In addition, the extension pipe constituting the nozzle part reduces the pressure loss of the cleaning body to be pumped as much as possible, and considers the strength and weight with respect to insertion into the cleaning part by cantilever, and has a round straight pipe. . The length of one extension tube is about 250 to 500 mm (250 mm or more and 500 mm or less), and it is also possible to change the length appropriately and use it in combination. However, considering the deflection in the length direction of the entire connected extension pipe portion, a single type of extension pipe of 250 mm is preferable.

  The dry ice used for the cleaning body is in the form of pellets and / or powder, and preferably is a cylindrical dry ice pellet of about φ3 mm × 6 to 8 mm.

  The outline of the structure of the deposit removal method and apparatus in the water pipe boiler of this invention is shown in FIG. 1 centering on an apparatus.

  The deposit removing device 1 in the water tube boiler mixes dry ice pellets and / or dry ice powder (hereinafter referred to as pellets) with the high-pressure compressed air supplied from the compressor 4 to produce a cleaning body. The cleaning machine main body 2 is supplied to the nozzle unit, and the cleaning unit supplied from the cleaning machine main body 2 through the cleaning body supply hose 11 is peeled and sprayed at a high pressure to the cleaning part. The pellets are artificially supplied from the dry ice cold storage BOX 3 to the cleaning machine body 2 as appropriate.

  The nozzle unit 5 includes an extension pipe part 6 to which one or a plurality of extension pipes 7 are connected, and a nozzle part 8 for injecting the cleaning body into the separation / cleaning part at a high pressure.

  Here, the detailed configuration and operation contents of the washing machine body 2 and the compressor 4, such as engine start / stop, valve opening / closing operation, pressure adjustment, etc., and further, pellet pulverization in the washing machine body 2 are non-patented. Since it is disclosed in Document 1 and other related documents, this description focuses on functions related to cleaning.

The extension pipe 7 constituting the nozzle unit 5 will be described with reference to FIG.
FIG. 2 shows the configuration of the extension pipe 7. The pipe 7c is assembled with a pipe 7c for transporting the cleaning body and a fastener A7b for freely holding the cap nut 7a at one end of the pipe 7c. The connecting screw 7d is fixedly welded and connected to the other end of the pipe 7c with the cap nut 7a of the other extension pipe 7. In this case, the length of the extension tube 7 is 250 mm, but the length may be changed as appropriate.

  From the viewpoint of work efficiency, the worker who performs the cleaning according to the present invention can perform cleaning while operating the injection nozzle fixedly at a fixed location.

  In the case of a water pipe boiler, the distance between the "water pipe" to be cleaned and the cleaning operator is greatly separated between the water pipe in the front row and the last water pipe due to its structural characteristics, and there is a difference of several meters or more at the maximum. There can be.

  In order to perform cleaning while operating the injection nozzle fixedly at a fixed location, the maximum extension pipe length can be changed according to the distance to the object to be cleaned, i.e., a variable type that connects multiple extension pipes (joint (Additional connection type) is desirable.

From this point, the extension pipe 7 ensures a bending strength for becoming a cantilever type when peeling deposits adhering to the outer surface of the water pipe section, and prevents unnecessary pellet clogging in the extension pipe which is a midway path. Therefore, the material is stainless steel, outer diameter 16mm × inner diameter 12mm × wall thickness 2mm, length 250
mm.

The injection nozzle part 8 which comprises the said nozzle part 5 is demonstrated based on FIG.
The injection nozzle portion 8 has a configuration in which a collar 8d and a fastener B8b are welded and fixed to the nozzle 8c in a state in which the cap nut can be moved freely, and the extension tube 7 is connected to the cap nut 8a. The tube 7 is fixed with a connection screw 7d.

  The nozzle 8 is light, strong, easy to handle, has little clogging of the cleaning body during injection, pressure loss, etc., and the internal airflow is not turbulent. The material is stainless steel and the outer diameter is 10 mm x inner diameter 6 mm x wall thickness. A 2 mm cylindrical nozzle was used.

[Example 1]
As Example 1, an example of cleaning the water pipe boiler shown in the conventional example (FIG. 5) will be described with reference to FIG.

  The specification of the water tube boiler is as shown in FIG. 5a), but the outer size is a medium-sized water tube boiler having a depth of 6,175 mm and a width of 3,407 mm (width of the water tube storage portion of 1,460 mm). About 1,400 water pipes are connected to the water pipe storage section between the water drum (the lower side of FIG. 5d) and the steam drum (the upper side of FIG. 5d) arranged vertically. The water pipe gap is very narrow at 30 mm.

  The deposit removing apparatus 1 is a 1.6 MPa screw compressor 4, a dry ice cleaning machine sold by Greentech Japan Co., Ltd., a cleaning machine body 2, and a pellet having a cylindrical shape of about φ3 mm × 6 to 8 mm. .

  The extension pipe portion 6 of the nozzle portion 5 has the structure shown in FIG. 2, and the pipe 7 c is made of stainless steel, the outer diameter is 16 mm × the inner diameter is 12 mm × the thickness is 2 mm, the length is 250 mm, and the cap nut 7 a is adjacent to each other. Since the gap between the water pipes is 30 mm, the structure has an inner diameter screw of M20 (so that the maximum diameter of the cap nut 7a is 25 mm). With the cap nut 7a inserted into one end of the pipe 7c, the fastener A is welded and fixed to the pipe 7c so that the cap nut 7a can be freely rotated. On the other hand, in order to connect the other end of the pipe 7c in combination with the cap nut 7a of the other extension pipe 7, a structure in which a connection screw 7d is fixed to the other end of the pipe 7c by welding is used. The cap nut A7a, the fastener A7b, and the connection screw 7d are all made of stainless steel.

  The number of connections of the extension pipe 7 is such that the nozzle part 5 is inserted from both ends A and B described in “Insertion of the nozzle part into the water pipe boiler” in FIG. Reduced the number of connections. In this embodiment, the required length of the extension pipe 7 from one side is 2,400 mm, and the required number of connections of the extension pipe is ten. At this time, the total weight of the extension pipe part 6 is as light as 2 kg, which is a weight that does not interfere with the cleaning operation.

  The injection nozzle portion 8 is a cylindrical nozzle 8c having the outer diameter of 10 mm, the inner diameter of 6 mm, and the thickness of 2 mm as shown in FIG. 3, and the injection direction of the nozzle is 45 degrees with respect to the axis of the extension pipe portion 7. Has a slope. All of the cap nut B8a, the fastener B8b, the nozzle 8c, and the collar 8d are made of stainless steel.

The result of cleaning the connecting portion of the water pipe connected to the water drum of the water pipe boiler under these conditions will be described with reference to FIG.
The upper part on the left side of FIG. 4 shows the connection part of the water pipe before washing, the lower part shows the middle part of the water pipe before washing, the upper part on the right side shows the connection part of the water pipe after washing, and the lower part shows the water pipe after washing. The middle part of is shown.

  As can be seen from this figure, the deposits adhering to the outer surface of the water pipe part could be sufficiently removed.

  As described above, even if the inside of the water tube boiler is complicated and narrow, the inside of the water tube boiler that can efficiently peel off the deposits attached to the water pipe that is the object to be cleaned with an inexpensive and simple structure. A deposit removal method and apparatus could be realized.

DESCRIPTION OF SYMBOLS 1 ... Deposit removal apparatus 2 ... Main body of washing machine 3 ... Dry ice cold storage BOX
4 ... Compressor 5 ... Nozzle part 6 ... Extension pipe part 7 ... Extension pipe 7a ... Cap nut A
7b ... Fastener A
7c ... Pipe 7d ... Connection screw 8 ... Injection nozzle part 8a ... Cap nut B
8b ... Fastener B
8c ... Nozzle 8d ... Collar 9 ... Joint 10 ... Air supply hose 11 ... Cleaner supply hose

Claims (8)

  A method for removing deposits in a water tube boiler by spraying pellet-shaped or powder-shaped dry ice to which pressure is applied in the water tube boiler and cleaning the outer surface of the water tube part, and a cleaning machine for mixing dry ice and compressed air The main body and the cleaning body, which is a mixed gas of dry ice and compressed air produced by the main body of the washing machine, are configured to be sprayed to the outer surface of the water pipe portion by the nozzle portion, and the deposits attached to the outer surface of the water pipe portion are peeled A method for removing deposits in a water tube boiler.   The nozzle part includes an extension pipe part connected to a plurality of extension pipes, and an injection nozzle part in which a direction in which a mixed gas of dry ice and high-pressure compressed air is blown out is 30 to 60 degrees with respect to the axial direction of the extension pipe part The method for removing deposits in a water tube boiler according to claim 1, comprising:   The extension pipe includes a cylindrical pipe and a fastener for freely holding a cap nut at one end of the pipe with a fastener and connecting the other end to the cap nut of another extension pipe. The extension pipe part is formed by connecting one or a plurality of the extension pipes in combination with a position where the deposit attached to the outer surface of the water pipe part is peeled off. The deposit removal method in the water tube boiler of 2.   4. The method for removing deposits in a water tube boiler according to claim 1, wherein the dry ice is in the form of pellets and / or powder.   A method for removing deposits in a water tube boiler by spraying pellet-shaped or powder-shaped dry ice to which pressure is applied in the water tube boiler and cleaning the outer surface of the water tube part, and a cleaning machine for mixing dry ice and compressed air The main body and the cleaning body, which is a mixed gas of dry ice and compressed air produced by the main body of the washing machine, are configured to be sprayed to the outer surface of the water pipe portion by the nozzle portion, and the deposits attached to the outer surface of the water pipe portion are peeled off. An apparatus for removing sediment in a water tube boiler.   The nozzle part includes an extension pipe part connected to a plurality of extension pipes, and an injection nozzle part in which a direction in which a mixed gas of dry ice and high-pressure compressed air is blown out is 30 to 60 degrees with respect to the axial direction of the extension pipe part The apparatus for removing deposits in a water pipe boiler according to claim 5, comprising:   The extension pipe includes a cylindrical pipe and a fastener for freely holding a cap nut at one end of the pipe with a fastener and connecting the other end to the cap nut of another extension pipe. 6. The extension pipe part is formed by connecting one or more of the extension pipes in combination with a position where the deposit attached to the outer surface of the water pipe part is peeled off. The deposit removal apparatus in the water tube boiler as described in 6.   8. The apparatus for removing deposits in a water tube boiler according to claim 5, wherein the dry ice is in the form of pellets and / or powder.