AUTOMATED SPRAY COATING FACILITY FOR RUNNING LANCE PIPES

TECHNICAL FIELD
[0001] The present disclosure relates to design and develop an automated spray coating facility with anti-stick coating solution on the running Linz-Donawitz (LD) lance pipes to reduce the lance jamming problem of steel making shops in the steel industry.

BACKGROUND
[0002] Background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
[0003] Iron and steel processing presents some of the world’s most challenging operational environments for equipment and people. One of the critical problems in the iron and steel processing is of lance jamming in primary steel making process. During blowing a supersonic jet of oxygen on a molten slag and metal surfaces, a thermal lance gets coated with the splashed molten metal slag. Due to heavy deposition of molten metal slag on the outer surface of the thermal lance, the thermal lance’s diameter increases to such an extent that it becomes extremely difficult to take the thermal lance in and out from a fixed diameter of a Linz-Donawitz (LD) converter hood. This is called “lance jam” or “skulling” and when it happens, the oxygen blowing has to be stopped and deposited melt on the thermal lance needs to be removed by deep blowing, hammering, or replacement with a new thermal lance. The process of lance jam cutting and new lance replacement result in inescapable delays and production loss which severely affects the production process. The process of lance jam cutting takes almost take 15-20 minutes to remove the deposited metal slag properly from the thermal lance and sometimes 30-40 minutes in case of heavy deposition.
[0004] Additionally, a lot of safety concerns are also involved in the lance jam cutting process as it is done manually by workers in extremely difficult working conditions of the gaseous, dusty, and hot environment within a confined space at about 23-meter height oxygen blowing platform.
[0005] Further, lance jamming has a substantial negative impact on production and plant safety. There is an average production downtime of 50 min/day in a production unit due to the lance jam cutting process which cost a huge amount in terms of plant productivity.
[0006] Various approaches have been suggested in the state of the art. One such approach includes the application of the anti-stick coating on the thermal lance, due to which production has been improved by reducing the downtime due to the delay caused in lance jam cutting.
[0007] Accordingly, there is a need for a method and a system of spraying solution precursor feedstock materials on the thermal lance during the operation of the thermal lance so as to avoid sticking of the molten slag on the surface of the thermal lance.

OBJECTS OF THE DISCLOSURE
[0008] In view of the foregoing limitations inherent in the state of the art, some of the objects of the present disclosure, which at least one embodiment herein satisfy, are listed hereinbelow.
[0009] It is a general object of the present disclosure to provide a method and a system of spraying solution precursor feedstock materials on the thermal lance during the operation of the thermal lance so as to avoid sticking of the molten slag on the surface of the thermal lance.
[0010] It is an object of the present disclosure to provide a spraying method of spraying the solution precursor feedstock materials into a specifically designed ring assembly of spraying guns to achieve uniform coatings over the running lance surfaces to reduce the lance jamming and manual interruption during lance jam cutting and enhance the lance pipe life.
[0011] These and other objects and advantages of the present invention will be apparent to those skilled in the art after a consideration of the following detailed description taken in conjunction with the accompanying drawings in which a preferred form of the present invention is illustrated.

SUMMARY
[0012] This summary is provided to introduce concepts related to an automated spray coating facility. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.
[0013] The present disclosure relates to a spraying system for online lance coating. The spraying system includes a paint tank; a paint manifold connected to an outlet of the paint tank; a plurality of electric airless spray pumps connected at their inputs to the paint manifold through respective pipes; a plurality of airless spraying guns connected to outlets of the plurality of electric airless spray pumps through respective pipes; and a ring-shaped assembly placed on a platform available at a hood surrounding a thermal lance, wherein the plurality of airless spraying guns are mounted at a uniform distance and angle from each other on top of a gun mounting system of the ring-shaped assembly.
[0014] In an aspect, the number of the plurality of electric airless spray pumps corresponds to the number of the plurality of airless spraying guns.
[0015] In an aspect, the plurality of airless spraying guns are mounted on top of the gun mounting system of the ring-shaped assembly at 90 degrees from each other.
[0016] In an aspect, tips of the plurality of airless guns are made out of the highest grade of tungsten carbide.
[0017] In an aspect, the platform available at the hood surrounding the thermal lance is at a height of 23 meters from the ground.
[0018] In an aspect, the plurality of airless spraying guns mounted over the ring-shaped assembly are placed around the lance pipe.
[0019] In an aspect, each of the plurality of airless spraying guns has two inlets, one is connected with hose pipes carrying a boron nitride paint and other one is connected with nitrogen line hose pipes.
[0020] In an aspect, the ring-shaped assembly is made from stainless steel.
[0021] In an aspect, the plurality of airless spraying guns are kept approximately 12 inches away from the surface of the thermal lance and aimed straight at the surface of the thermal lance for uniform spraying.
[0022] In an aspect, the pipes connecting the paint tank to the plurality of electric airless spray pumps and the pipes connecting the plurality of electric airless spray pumps to the plurality of airless spraying guns are made of stainless steel.
[0023] In an aspect, the plurality of electric airless spray pumps includes four pumps, and the plurality of airless spraying guns includes four guns.
[0024] Various objects, features, aspects, and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
[0025] The illustrated embodiments of the subject matter will be best understood by reference to the drawings, wherein like parts are designated by like numerals throughout. The following description is intended only by way of example, and simply illustrates certain selected embodiments of devices, systems, and methods that are consistent with the subject matter as claimed herein, wherein:
[0026] FIGS. 1 and 2 illustrates a schematic view of a spraying system for online lance coating in accordance with an embodiment of the present disclosure;
[0027] FIG. 2 illustrates a schematic of a control panel of the spraying system in accordance with an embodiment of the present disclosure; and
[0028] FIG. 3 illustrates an isometric view of the ring-shaped assembly made for online boron nitride spraying system in accordance with an embodiment of the present disclosure; and
[0029] FIG. 4 illustrates shows a top view of the ring-shaped assembly in an operational mode in accordance with an embodiment of the present disclosure.

DETAILED DESCRIPTION
[0030] The detailed description of various exemplary embodiments of the disclosure is described herein with reference to the accompanying drawings. It should be noted that the embodiments are described herein in such details as to clearly communicate the disclosure. However, the amount of details provided herein is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure as defined by the appended claims.
[0031] It is also to be understood that various arrangements may be devised that, although not explicitly described or shown herein, embody the principles of the present disclosure. Moreover, all statements herein reciting principles, aspects, and embodiments of the present disclosure, as well as specific examples, are intended to encompass equivalents thereof.
[0032] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms “a”, “an”, and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises”, “comprising”, “includes”, “consisting” and/or “including” when used herein, specify the presence of stated features, integers, steps, operations, elements and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and/or groups thereof.
[0033] It should also be noted that in some alternative implementations, the functions/acts noted may occur out of the order noted in the figures. For example, two figures shown in succession may, in fact, be executed concurrently or may sometimes be executed in the reverse order, depending upon the functionality/acts involved.
[0034] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which example embodiments belong. It will be further understood that terms, e.g., those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
[0035] Embodiments described herein relate to design and develop an automated spray coating facility with anti-stick coating solution on a running LD thermal lance to reduce the lance jamming problem of steelmaking shops in the steel industry. More specifically, the present disclosure relates to a novel spraying method of spraying the solution precursor feedstock material into a specifically designed ring-shaped assembly of airless spraying guns to achieve uniform coatings over the running thermal lance surfaces to reduce the lance jamming and manual interruption during lance jam cutting and enhance the life of the thermal lance. Thus, the present disclosure provides an easy solution to lance jamming problem, in which online automated spraying on the running lance can significantly improve the production time and more importantly the workplace safety of the jam cutting workers.
[0036] In the present disclosure, a ring-shaped assembly spraying system has been proposed and designed keeping in mind the restricted and confined space available on a platform mounted at 23 meters above ground. The spraying system proposed herein has been made to reduce the manual operation, safety concerns, and production downtime. Installation and commissioning of the spraying system proposed herein have been done at the production site and the coating performance has been verified by the repeated trials.
[0037] Various trials with boron nitride paint spraying have been done at different process parameters. During trials, pump pressure and tip orifice size were found to be the most critical parameters affecting the coating properties. Accordingly, an online spraying system was optimized at a particular pump pressure to obtain a uniform and smooth coating on the running thermal lance. Also, the boron nitride paint/coating was carried out with optimized process parameters and coating performance evaluated by checking the lance jam cutting frequency. During the trails, it was observed that lance jam cutting has been reduced significantly by half by application of boron nitride paint/coating.
[0038] Thus, with the implementation of the spraying system proposed herein, lance jam cutting frequency (LJCF) has reduced to almost half and reached to 7-8 heats from 3-4 heats. Also, sticking of the molten metal slag on the coated thermal lance surface was found to be very weak and easily removable on the coated thermal lance. Thus, boron nitride paint/coating has shown great potential to improve lance performance by reducing the deposition of molten metal and slag on a lance and thereby to increase the plant productivity.
[0039] FIGS. 1A and 1B show schematic of a complete set up of a spraying system 100 for online lance coating in accordance with an embodiment of the present disclosure. This spraying system 100 proposed herein has been specifically designed for the vessel #3 of LD#2 and fixed at the 23-meter height platform from where the lances are inserted into the vessel through a hood for oxygen blowing.
[0040] In the online spraying system 100, a paint tank 102 is provided with an agitator 104 is provided. The paint tank 102 is filled with boron nitride paint which is agitated at regular intervals so that it will not get dried before application. At an outlet of the paint tank 102, a paint manifold 106 is connected to distribute the boron nitride paint supply into four respective stainless steel (SS) pipes to carry out the boron nitride paint from the paint manifold 106 into inputs of four respective electric airless spray pumps 108A, 108B, 108C, 108D (hereinafter, collectively referred to as 108). The SS pipes have been chosen for paint supply line for the longevity of the spraying system 100 and also to avoid any type of corrosion in the line due to the boron nitride paint.
[0041] Further, four airless spraying guns (Graco made) 110A, 110B, 110C, 110D (hereinafter, collectively referred to as 110) are connected to outlets of the plurality of electric airless spray pumps 110 through respective flexible hose pipes passing through a fluid manifold 112.
[0042] These airless spraying guns 110 are mounted over a ring-shaped assembly 114 placed around a thermal lance 116, wherein the airless spraying guns 110 are mounted at a uniform distance and angle from each other on top of a gun mounting system of the ring-shaped assembly 114. In an aspect, the airless spraying guns 110 are mounted on top of the gun mounting system of the ring-shaped assembly 114 at 90 degrees from each other.
[0043] Further, the airless spraying guns 110 has two inlets, one is connected with the hose pipes carrying the boron nitride paint and other one is connected with nitrogen line hose pipes. Compressed nitrogen gas is used to break the boron nitride paint and atomize the boron nitride paint particle to get uniform coating and better coverage. In an alternative aspect, compressed air can also be used in place of nitrogen gas based on the availability at a plant site.
[0044] FIG. 2 shows a schematic of a control panel 200 of the spraying system 100 which has been specially made near the control panel of a lance moving system so that spraying can be controlled with the up and down movement of thermal lance 116.
[0045] Further, as mentioned above, the spraying system 100 is specially designed keeping in mind the restricted and confined space available at the 23-meter platform available at a hood surrounding the thermal lance 116. The arrangement of semi-automated ring-shaped assembly 114 at the platform is made to reduce the manual operation. Initially, it was thought to fix the ring-shaped assembly 114 permanently on the hood but later on it was finalised to not to give permanent fixture to avoid any damages to the ring-shaped assembly 114 and the airless spraying guns 110 from very high temperature exposure and falling of heavy jam from the thermal lance during jam cutting. So, the ring-shaped assembly 114 is being kept on the hood during coating only and taken away from the hood while not in operation. The ring-shaped assembly 114 is made from the stainless-steel material and is placed over the holder on the hood during coating/painting of the thermal lance 116.
[0046] In an aspect, as shown in FIG. 1B, the spraying system 100 may include water tank 118 for cleaning purposes.
[0047] FIG. 3 shows an isometric view of the ring-shaped assembly 114 made for online boron nitride spraying at the 23-meter platform in LD#2. FIG. 4 shows a top view of the ring-shaped assembly 114 in an operational mode. As can be seen from FIGS. 3 and 4, the four airless spraying guns 110 are fixed on top of the gun mounting system of the ring-shaped assembly 114. Each gun 110 is fixed at 90 degrees from each other to cover the whole surface area of the thermal lance 116 during coating and/or painting. Further, in an aspect, a distance of the airless spraying guns 110 from each other and lance surface are chosen in such a way to obtain very uniform coating throughout the lance surface and to avoid any over spraying or overlapping. All spray gun tips are made out of the highest grade of tungsten carbide, the most abrasive-resistant material used in the manufacturing of airless spraying. Also, an airless spray tip determines the fluid flow, i.e., the amount of coating applied and the spray pattern (fan width). So, selecting the correct spray tip for the job is an important decision. Different spray tips have been tried out initially to optimize the fan width and uniform coverage. Graco 221 spray tip is finally selected for the spray coating.
[0048] In an aspect, the spray guns 110 should be kept approximately 12 inches (30.5 cm) from the surface of the thermal lance 116 and aimed straight (both horizontally and vertically) at the surface for uniform spraying.
[0049] Further, the ring-shaped assembly 114 is fixed over the platform available on the hood surrounding the lance during the coating process and thermal lance pipe 116 is moved vertically up and down to cover the whole length of the lance. The thermal lance pipe 116 is moved with slowly to get a uniform coating and full coverage on the surface.
[0050] With the application of an anti-stick coating of boron nitride paint, production can be improved by reducing the downtime due to the delay caused in lance jam cutting. On an average (as per calculation), there will be big financial saving in multiple of crores per annum along with workplace safety improvement if this work gets implemented in the LD #2. This calculation is as per the assumptions if the downtime reduced to half from 50 min/day to 25 min/ day by applying boron nitride coating. Anti-stick coating provides an easy solution to lance jamming problem, online automated spraying on the running lance pipes can significantly improve the production time and more importantly the workplace safety of the jam cutting workers.
[0051] Furthermore, those skilled in the art can appreciate that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure. It will be appreciated that several of the above-disclosed and other features and functions, or alternatives thereof, may be combined into other systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations, or improvements therein may subsequently be made by those skilled in the art without departing from the scope of the present disclosure as encompassed by the following claims.
[0052] The claims, as originally presented and as they may be amended, encompass variations, alternatives, modifications, improvements, equivalents, and substantial equivalents of the embodiments and teachings disclosed herein, including those that are presently unforeseen or unappreciated, and that, for example, may arise from applicants/patentees and others.
[0053] While the foregoing describes various embodiments of the present disclosure, other and further embodiments of the present disclosure may be devised without departing from the basic scope thereof. The scope of the present disclosure is determined by the claims that follow. The present disclosure is not limited to the described embodiments, versions or examples, which are included to enable a person having ordinary skill in the art to make and use the invention when combined with information and knowledge available to the person having ordinary skill in the art.

We claim:

1. A spraying system (100) for online lance coating, comprising:
a paint tank (102);
a paint manifold (106) connected to an outlet of the paint tank (102);
a plurality of electric airless spray pumps (108) connected at their inputs to the paint manifold (106) through respective pipes;
a plurality of airless spraying guns (110) connected to outlets of the plurality of electric airless spray pumps (108) through respective pipes; and
a ring-shaped assembly (114) placed on a platform available at a hood surrounding a thermal lance (116), wherein the plurality of airless spraying guns (110) are mounted at a uniform distance and angle from each other on top of a gun mounting system of the ring-shaped assembly (114).
2. The spraying system (100) as claimed in claim 1, wherein the number of the plurality of electric airless spray pumps (108) corresponds to the number of the plurality of airless spraying guns (110).
3. The spraying system (100) as claimed in claim 1, wherein the four airless spraying guns (110) are mounted on top of the gun mounting system of the ring-shaped assembly (114) at 90 degrees from each other.
4. The spraying system (100) as claimed in claim 1, wherein tips of the plurality of airless spraying guns (110) are made out of a highest grade of tungsten carbide.
5. The spraying system (100) as claimed in claim 1, wherein the platform available at the hood surrounding the thermal lance (116) is at a height of 23 meters from the ground.
6. The spraying system (100) as claimed in claim 1, wherein the plurality of airless spraying guns (110) mounted over the ring-shaped assembly (114) are placed around the lance pipe (116).
7. The spraying system (100) as claimed in claim 1, wherein each of the plurality of airless spraying guns (110) has two inlets, one is connected with hose pipes carrying a paint and other one is connected with nitrogen line hose pipes.
8. The spraying system (100) as claimed in claim 1, wherein the ring-shaped assembly (114) is made from stainless steel.
9. The spraying system (100) as claimed in claim 1, wherein the plurality of airless spraying guns (110) are kept approximately 12 inches away from the surface of the thermal lance (116) and aimed straight at the surface of the thermal lance for uniform spraying.
10. The spraying system (100) as claimed in claim 1, wherein the pipes connecting the paint tank (102) to the plurality of electric airless spray pumps (108) and the pipes connecting the plurality of electric airless spray pumps (108) to the plurality of airless spraying guns (110) are made of stainless steel.
11. The spraying system (100) as claimed in claim 1, wherein the plurality of electric airless spray pumps (108) includes four pumps, and the plurality of airless spraying guns (110) includes four guns.