TW201505707A - Autoclave heating jacket - Google Patents

Abstract

An autoclave heating jacket can include a heating fluid collar, a fluid inlet, a fluid outlet, and a plurality of fluid flow baffles. The heating fluid collar can have an outer wall which includes an upper contact surface and a lower contact surface forming an enclosed chamber when engaged with an outer surface of an autoclave. The fluid inlet can be oriented through the outer wall and is capable of directing a heating fluid into the enclosed chamber. The fluid outlet can be oriented through the outer wall but is capable of directing the heating fluid out of the enclosed chamber. The plurality of fluid flow baffles can be oriented within the enclosed chamber so as to direct the heating fluid along a predetermined pathway within the enclosed chamber.

Description

Autoclave heating jacket

This invention relates to heating jackets for use on autoclave vessels which are very strong under cyclic heating.

The use of polymers has increased significantly over the past few decades due at least in part to the versatility of the material properties available and the relatively low cost associated with the formation of complex shapes. Continuous and batch polymerization processes are available for a variety of polymer production facilities. Each process has advantages and disadvantages depending on various variables such as capital cost, throughput, polymer type, polymerization kinetics, and other priorities. Batch polymerization processes typically employ a polymerization reactor or autoclave that is heated to a suitable process temperature.

Heating of such polymerization reactors typically involves the use of a closed loop heating system that transfers heat from the heated fluid to the reactor. The heating system can include an external heating coil, an internal heating loop, a jacket system, or other similar heat transfer system. These systems can have inherent limitations in terms of heat distribution, heating rate, reliability, and operational constraints. Therefore, improvements in such heating systems on polymerization reactors continue to be sought and studied.

The autoclave heating jacket can include a heating fluid ring, a fluid inlet, a fluid outlet, and a plurality of fluid flow baffles. More specifically, the heating fluid ring can have an outer wall that includes an upper contact surface and a lower contact surface that form a closed chamber when engaged with the outer surface of the autoclave. The fluid inlet can be oriented to pass through the outer wall and can direct the heating fluid to the enclosed chamber in. Similarly, the fluid outlet can be oriented to pass through the outer wall and can direct the heated fluid out of the enclosed chamber. A plurality of fluid flow baffles can be oriented within the enclosed chamber to direct the heated fluid along a predetermined path within the enclosed chamber.

A polymeric autoclave having a composite external heating assembly is also described. The polymerization autoclave may include an autoclave vessel body, a heating jacket, and a heating pipe. The autoclave vessel body can have an internal reaction chamber and an outer surface including upper and lower portions. The heating jacket can be attached to the lower portion to form a closed chamber. The enclosed chamber has a plurality of fluid flow baffles configured to direct the heating fluid in the enclosed chamber and around the lower portion along the winding path. The heating pipe can be wound and attached to the upper portion. More specifically, the heating conduit can have a plurality of windings around the upper portion and is in fluid connection with the heating jacket. Thus, the heating fluid can be circulated through the enclosed chamber and the heating conduit to transfer heat to the internal reaction chamber. In addition, the heating jacket and the heating conduit together form a composite external heating assembly.

A method of repairing a polymeric autoclave to which an external heating coil is attached to an outer surface is also disclosed and described. When the heating coil has a weakened or leaking section in one of the outer surfaces of the autoclave, such defects can be effectively repaired using the method of the present invention. For example, the method can include removing a weakened or leaking section of the heating coil from the affected portion of the outer surface of the autoclave to retain the intact heating coil section on a respective portion of the outer surface. The heating jacket described above can be attached to the affected portion of the outer surface to form a closed chamber. The closed chamber can be fluidly coupled to the intact heating coil section. In this way, the polymerization autoclave can be repaired by providing a composite external heating assembly.

100‧‧‧Polymerized autoclave

102‧‧‧Composite external heating unit/external heating unit/heating unit

104‧‧‧heating jacket/autoclave heating jacket

106‧‧‧ autoclave container body/container body

108‧‧‧Heating pipe/heating coil

110‧‧‧ upper first import

112‧‧‧second import

114‧‧‧pressure relief valve

116‧‧‧ outer surface

118‧‧‧Transition room

120‧‧‧ Jacket fluid inlet/fluid inlet

122‧‧‧ Jacket fluid outlet / fluid outlet

124‧‧‧Transformation pipeline

200‧‧‧heating fluid ring

202‧‧‧Fluid flow baffle / lower flow baffle

204‧‧‧Fluid flow baffle / upper flow baffle

206‧‧‧Fluid flow baffle / partition baffle

208‧‧‧ outer wall

210‧‧‧Upper contact surface

212‧‧‧ lower contact surface

214‧‧‧Closed room

216‧‧‧ serpentine fluid flow path

218‧‧‧Internal curved surface

302‧‧‧Conical Reservoir

304‧‧‧Import

306‧‧‧lower/conical lower part

308‧‧‧Flange

310‧‧‧ autoclave outlet

312‧‧‧Internal reaction room

313‧‧‧First container wall

314‧‧‧heat pipe

316‧‧‧share outlet

402‧‧‧ first wall

404‧‧‧Internal coating

406‧‧‧ fluid flow path

1 is a perspective view of a polymerization autoclave according to an embodiment of the present invention; and FIG. 2 is a perspective view of an autoclave heating jacket according to an embodiment of the present invention, wherein a part of the phantom diagram shows the shading internal features; 1 is a cross-sectional view of a lower portion of a polymerization autoclave of one embodiment of the invention; FIG. 4 is a bottom cross-sectional view of a polymerization autoclave according to an embodiment of the present invention; and FIG. 5 is an external heating of a polymerization autoclave for repairing an embodiment of the present invention. System side Flow chart of the law.

It should be noted that the figures are merely illustrative of several embodiments of the invention and are not intended to limit the scope of the invention.

While the following embodiments are intended to be illustrative of the specific embodiments of the present invention, it will be understood that

Therefore, the following embodiments are set forth without any loss to the generality of any invention claimed and without any limitation to any claimed invention. Before the present invention is described in more detail, it is to be understood that the invention is not limited to It is also understood that the terminology used herein is for the purpose of describing the particular embodiments, and is not intended to All technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs, unless otherwise defined.

The singular forms "a", "an", "the" and "the" are used in the <RTI ID=0.0> </ RTI> </ RTI> <RTIgt; Thus, for example, reference to "heating fluid" includes a plurality of such fluids, and "import" refers to one or more of such features.

In the present invention, "comprise", "comprising", "contain", "have" and the like may have the meaning attributed to them in the U.S. Patent Law and may mean "include", "including" and the like, and are generally interpreted as open terms. The term "consisting of" is a closed term and includes only the specifically listed devices, methods, compositions, components, structures, steps or the like in accordance with the U.S. Patent. "Consisting essentially of" or "consisting essentially of (consist essentially) or "consist essentially" used in the apparatus, method, composition, component, structure, step or the like of the present invention. ) or similar terms The elements disclosed herein, but which may contain other structural groups, component components, method steps, and the like. However, such other devices, methods, compositions, components, structures, steps, or the like, etc., do not materially affect the devices, compositions, etc., as compared to the corresponding devices, compositions, methods, etc. disclosed herein. Basic and novel features of the method and the like. In more detail, "consisting essentially of" or "substantially by:" used in the apparatus, method, composition, component, structure, step or the like of the present invention. "consist essentially" or the like has the meaning attributed to it in the U.S. Patent Law, and the term is open-ended, thereby allowing the existence of the foreign matter as long as the basic or novel features are not The presence of the object varies, but does not include prior art embodiments. When using open-ended terms (such as "contains" or "includes"), it should be understood that the language "consisting essentially of" and "composed of" should be directly supported, as expressly stated.

In the context of a synthetic method, phrases such as "suitable for providing", "sufficient to cause" or "sufficient to produce" or similar phrases refer to reactions related to time, temperature, solvent, reactant concentration and the like. Conditions, variations in which to provide an effective amount or yield of the reaction product are within the general skill of the experimenter. The desired reaction product need not be the only reaction product or the starting material does not have to be completely consumed, as long as the desired reaction product can be isolated or otherwise used further.

It should be noted that ratios, concentrations, amounts, and other numerical data may be expressed in a range format herein. It is to be understood that the scope of the invention is to be construed as being in a Range, as if each value and sub-range includes "about 'x' to about 'y'". For purposes of illustration, the range of concentrations from "about 0.1% to about 5%" should be interpreted to include not only concentrations from about 0.1% to about 5% by weight that are specifically reported, but also individual concentrations within the specified range (eg, 1%, 2%, 3%, and 4%) and sub-ranges (eg, 0.5%, 1.1%, 2.2%, 3.3%, and 4.4%). In one embodiment, the term "about" This can include traditional rounding based on the effective number of values. In addition, the phrase "about "x" to "y"" includes "about "x" to about "y"".

When referring to a value or range, the term "about" as used herein is intended to mean a degree of variation in the value or range, such as within 10% of the specified limit value of the specified value or range, or 5% in one aspect. Inside.

In addition, if a feature or aspect of the invention is described in relation to a list or a Markush group, those skilled in the art will recognize that the invention also relates to any individual member or member of the Markusi group member. Group description. For example, if X is described as being selected from the group consisting of bromine, chlorine, and iodine, the technical scheme in which X is bromine and the technical scheme in which X is bromine and chlorine are fully described, as listed separately. For example, if features or aspects of the present invention are described in relation to the list, those skilled in the art will recognize that the present invention also relates to individual members or subgroups of members of the list or members of the Markusi group. Any combination description. Thus, if X is described as being selected from the group consisting of bromine, chlorine, and iodine and Y is described as being selected from the group consisting of methyl, ethyl, and propyl, then fully described and supported that X is bromine and Y is methyl. Technical solutions.

All percentages of the compositions as used herein are given in weight percent unless otherwise indicated. Unless otherwise specified, when referring to a solution of a component, the percentage is meant to be a percentage by weight of the composition including the solvent (eg, water).

The individual embodiments described and illustrated herein have discrete components and features that can be readily associated with those skilled in the art without departing from the scope or spirit of the invention. The features of any other several embodiments are separated or combined. Any of the methods may be performed in the order of the events or in any other order that is logically possible.

Unless otherwise indicated, the chemical, metallurgical, welding techniques and the like used in embodiments of the present invention are within the skill of the art. These techniques are fully described in the literature.

Batch polymerization typically involves repeated temperature cycling during various processing stages. Typically, the polymerization reactant is fed into the autoclave and the materials are heated to initiate polymerization and drive the reaction during the process. Upon completion, the materials are extruded or otherwise removed from the autoclave. Intermediate cleaning and washing stages can also be used between polymerization batches to provide a more consistent product quality. Unfortunately, such processes introduce significant temperature cycling changes in the autoclave along the autoclave wall and along adjacent heating systems, such as external heating coils. In addition, temperature differences across the autoclave and various parts of the heating system can create mechanical stresses at the welded joint and adjacent materials.

As an illustrative example, the formation of a divalent polyamine (such as nylon 6,6) can include reacting the nylon salt with an acid for several hours at a temperature of about 189-250 °C. The autoclave wall temperature is initially lower than the typical heating fluid temperature. The temperature and pressure conditions in the nylon 6,6 batch process cycle include initial startup, feed to the nylon salt, reaction stage, extrusion stage, and purge stage. During these various stages, the temperature change creates a temperature differential between the autoclave wall and the heating coil.

Table 1 provides an example of cyclic polymerization operating conditions.

Notably, the temperature difference between the heating coil and the wall of the autoclave can vary drastically over time. The external heating coil is welded to the outer surface of the autoclave in most cases. During the start of the reactor, the expansion of the heating coil is inhibited by the relatively cold autoclave wall. This creates a compressive load that exceeds the elastic deformation limit of the weld. This permanent deformation creates stress in the welded joint when the autoclave wall is subsequently heated to normal operating temperatures. Similar deformations occur during changes in temperature conditions, such as cooking, steam cleaning, washing, shutting down, and starting the reactor. In each In this case, the temperature change causes a temperature gradient across the weld. In the case of nylon 6,6 production, the batch cycle time can typically range from about 100 to 120 minutes for standard yields. Eventually, these repeated temperature differences cause low cycle fatigue damage at the welded joint between the external heating coil and the autoclave wall. This damage is primarily encountered at the lower portion of the external heating coil because the heating fluid is hottest near the lower inlet coil where the heating fluid temperature is highest. Therefore, in the lower portion of the externally heated coil, the temperature difference between the heating coil and the outer surface of the autoclave tends to be large, and is particularly noticeable in one to four windings before heating the coil. Unfortunately, spot welding at the location of the breakage can weaken the wall of the coated container over time and in some cases can strip the inner coating.

The autoclave heating jacket can be used to overcome this damage and reduce future damage due to low cycle fatigue. 1 illustrates a polymeric autoclave 100 having a composite external heating assembly 102 that incorporates the heating jacket 104. The polymerization autoclave can include an autoclave vessel body 106, a heating jacket, and a heating conduit 108. The autoclave vessel body can be any suitable vessel in which the polymerization reaction can be carried out. In general, a suitable container body can include an internal reaction chamber surrounded by an autoclave wall and capable of pressurization. While the operating conditions may vary, the autoclave vessel body may be adapted to maintain a pressure of at least 300 psia and in some cases at least 600 psia. The autoclave vessel body of Figure 1 shows an upper first inlet 110, a second inlet 112 and a pressure relief valve 114. The inlet can be used to feed the initial reaction to the internal reaction chamber, control the pressure, and/or introduce a graded polymerization reactant. It should be noted that, as will be appreciated by those skilled in the art, regardless of the description and location of such inlets and valves, such or other locations may be used in a manner different than that exhibited by the user for any design purpose.

Optionally, the autoclave container can be a coated container wherein the first container wall is coated with one or more inner layers. As a non-limiting example, the carbon steel wall may be coated with a stainless steel inner layer. The carbon steel wall provides a first mechanical strength to the container, while the stainless steel inner layer provides corrosion protection to the inner surface of the container that is in contact with the polymerization reactant and product at high temperatures and pressures. Other materials may also be suitable for the container wall, such as, but not limited to, carbon steel alloys (eg, HII carbon steel), refractory metal Gold, chromium alloys, composites thereof, and combinations thereof. In one example, the vessel wall may be formed from a chromium-molybdenum steel alloy (eg, 16Mo3) or the like. Similarly, the inner coating can be stainless steel (e.g., SS321) or the like.

The wall thickness of the container can vary, but is generally from about 15 mm to about 50 mm, and in most cases from about 20 mm to 40 mm. In one example, the container wall thickness can be 24 mm carbon steel and a 3 mm stainless steel inner cladding. The corresponding wall thickness of the heating conduit can also affect the extent of stress transmitted to the heating coil during temperature transitions. The wall thickness of the heated conduit is typically less than the wall thickness of the vessel and is generally less than about 25 mm. In one example, the heated conduit wall thickness can be from about 3 mm to about 6 mm, and in one particular example is 4 mm. In general, the ratio of the wall thickness of the vessel to the wall thickness of the conduit can be, for example, from about 2:1 to about 15:1, or from about 5:1 to about 9:1.

Referring again to Figure 1, the autoclave vessel body 106 can have an outer surface 116 that includes an upper portion and a lower portion. The heating jacket 104 can be attached to the lower portion, while the heating conduit 108 can be wrapped and attached to the upper portion. The terms "upper" and "lower" are relative terms and do not mean the upper and lower halves, but only the upper portion relative to the lower portion. The heating duct can have a plurality of windings around the upper portion. The number of wraps can vary significantly, but typically exceeds ten wraps, and in some cases up to or over twenty wraps. The outer width of the heating conduit can vary, such as from about 50 mm to about 100 mm. In addition, each wrap generally has a small gap to expose the outer surface intermediate the continuous wrap of the heating pipe. These gaps are generally limited to improve heat transfer to the autoclave, but in most cases are limited to no more than 50% (and in most cases less than 20%) the width of the surrounding heating conduit. The heating conduit can have a variety of cross-sectional shapes such as, but not limited to, a semi-tubular shape, a full tubular shape, a U-shaped channel, a V-shaped channel, and the like. The heating conduit can be fluidly coupled to the heating jacket via a suitable galvanic couple, such as transition chamber 118. Thus, the heating fluid can be introduced into the external heating assembly 102 via the jacketed fluid inlet 120 and circulated through the heating jacket to the jacketed fluid outlet 122. The transition conduit 124 can direct the heating fluid to a transition chamber that is fluidly coupled to the heating conduit. In this manner, heat from the heated fluid can be transferred to the internal reaction chamber of the polymerization autoclave 100 to maintain the desired temperature. Although a variety of heating fluid may be used, but non-limiting examples include Thermanol 66®, Dowtherm ^TM and mixtures thereof.

Optionally, the heating jacket can be attached to the upper portion of the outer surface and the heating conduit attached to the lower portion. In another alternative, multiple heating jackets may be attached to the outer surface in series. Multiple heating jackets may be directly connected to one another or may be connected to an intermediate heating conduit to provide an alternating heating jacket-heating conduit configuration. The heating jacket and the heating conduit can be attached to different and non-overlapping portions of the outer surface. The heating jacket and the heating pipe may each cover different proportions of the outer surface depending on the heat transfer efficiency and other considerations. However, as a general rule, the heating jacket can cover from 3% to 40% of the outer surface, while the entire heating assembly can typically cover from 30% to 80% of the outer surface, and typically from 40% to 70%. In many embodiments, the heating jacket covers the lower portion of the outer surface and the heating assembly together covers about 5% to about 30% of the surface. With regard to surface coverage, the gap between the windings in the heating pipe is included in the coverage by the respective heating means.

Turning to Figure 2, the autoclave heating jacket 104 is shown in more detail than the autoclave vessel body. The autoclave heating jacket can include a heating fluid ring 200, a fluid inlet 120, a fluid outlet 122, and a plurality of fluid flow baffles 202, 204, and 206. More specifically, the heating fluid ring can have an outer wall 208 that includes an upper contact surface 210 and a lower contact surface 212 that form a closed chamber 214 when engaged with the outer surface of the autoclave. The outer wall can have an annular shape that is complementary to the outer surface of the autoclave to provide a substantially annular volume to the enclosed chamber. Alternatively, the outer wall may have other shapes as long as the closed chamber is formed such that the heating fluid can pass through the outer surface of the autoclave.

The enclosed chamber includes a plurality of fluid flow baffles configured to direct the heated fluid along a predetermined path within the enclosed chamber. A winding path can be designed in the enclosed chamber that flows around the lower portion of the polymerization autoclave. The winding paths can be arranged to minimize non-uniformity of heat transfer to the internal reaction chamber. In FIG. 2, the fluid flow baffle includes a divider baffle 206 that forms a barrier within the enclosed chamber to force a heating fluid to circulate in the enclosed chamber. The fluid inlet 120 and fluid outlet 122 of the heating jacket can be oriented to abut each other such that the heating fluid substantially traverses the entire enclosed chamber. The fluid inlet can be oriented to pass through the outer wall 208 and can direct the heating fluid Guided into the enclosed chamber 214. Similarly, the fluid outlet can be oriented to pass through the outer wall but can direct the heated fluid out of the enclosed chamber.

As noted, a variety of baffles can be used to direct the flow of heated fluid along the winding path. The baffles can be oriented to define various winding paths such as, but not limited to, serpentine fluid flow paths, circumferential reciprocating fluid flow paths, or the like. For example, alternate upper flow baffles 204 and lower flow baffles 202 may obtain a serpentine fluid flow path 216. Notably, the baffles each include an inner curved surface 218 that engages the outer surface of the autoclave container body to force fluid to flow around the baffles. Thus, the upper fluid flow baffle retains an open flow path above the baffles while the lower flow baffle retains an open flow path below the respective baffles. Although the description shows a vertically varying serpentine flow path, the baffle can also be placed to induce a horizontal flow change. A variety of baffle configurations are available, but complex and or multiple baffle configurations can produce excessive heads. This increase in pressure within the heating assembly may increase the probability of causing breakage within the heating assembly, requiring high pressure heating of the fluid pump and/or increased operating costs. In any event, an internal flow baffle is used to provide an effective heat transfer volume and the substantial surface of the lower portion of the outer jacket is covered. The open enclosed chambers provide a non-uniform heating fluid flow path. In contrast, heating pipes typically have a uniform cross-sectional area (semi-tube, full tube, or the like).

3 illustrates an autoclave heating jacket 104 and a heating coil 108 attached to the outer surface 116 of the polymerization autoclave. The heating jacket may optionally include a vent 300 in the bottom surface of the heating ring to enable closing and/or cleaning of the heating assembly 102. As previously described, the heating jacket can include an upper contact surface 210 and a lower contact surface 212 that engage the outer surface 116 of the autoclave to form a closed chamber 214. In this embodiment, the upper contact surface can be an annular ridge that defines the top plate of the ring. Similarly, the lower contact surface can be an annular flange that defines the bottom plate of the ring. Thus, the heating jacket can include a ring having an annular vertical outer wall joined to the bottom plate and the top plate, the bottom plate and the top plate together bringing the heating fluid against the lower portion of the outer surface.

The heating jacket can be able to withstand the expected operating temperature, conditions and repeated temperature cycling Any suitable material is formed. Non-limiting examples of suitable materials include carbon steel, stainless steel, steel alloys including chromium-molybdenum alloys such as 16Mo3 and the like, and combinations thereof. In one example, the heating jacket can be formed from a chromium-molybdenum steel alloy. Typically, the heating jacket can be welded to the outer surface using a high temperature solder alloy. Non-limiting examples of suitable solder alloys can include alloys comprising Mn-Mo, W2 Mo, G 46 AM G4MO, E Mo B32 H5, and combinations thereof. Commercially available solder alloys (ie, filler metals) such as, but not limited to, Nertalic 86®, Union® I-Mo, and SL® 12G can also be used.

While other types of autoclaves can be used with the heating assembly 102, an internal heating manifold can also be used. For example, the internal heating manifold can include a conical reservoir 302 having an inlet 304. A conical reservoir can be placed within the lower portion 306 of the autoclave that is attached to the container body 106 at the flange 308. The lower portion includes an autoclave outlet 310 that allows the product to be removed from the internal reaction chamber 312 for further processing (e.g., extrusion, drawing into fibers, molding, etc.). In some cases, the wall thickness of the lower portion may be greater than the wall thickness of the first container wall 313. For example, the lower thickness can be about 10% to 40% thicker than the first container wall. Similarly, the jacket thickness can be 10% to 40% greater than the corresponding heating pipe. The thickness of the jacket may range from about 8 mm to about 25 mm, and in some cases from 10 mm to 18 mm, although other thicknesses may be used. For example, the thickness of the heating jacket can be 12 mm or 16 mm. In another example, the thickness of the outer casing wall can be less than the thickness of the top and bottom plates. As with heating the conduit, the ratio of the lower thickness to the thickness of the heating jacket can range from about 2:1 to about 15:1, and in some cases from about 5:1 to about 9:1.

The internal heating manifold can further include one or more heating tubes 314 each fluidly coupled to the conical reservoir. The heating tube can be connected (not shown) to a common outlet 316 for recirculating and/or reheating the cooled heating fluid. In another alternative, the polymerization autoclave can be an agitated autoclave that includes an internal mixer. Internal mixers are typically oriented vertically along the line in the internal reaction chamber. The internal mixer can increase the homogeneity of the polymerization conditions and shorten the polymerization time.

Referring now to Figure 4, a bottom view of the polymerization autoclave 100 is shown attached to the autoclave vessel body. The autoclave of 106 heats the jacket 104. As described above, the container body is attached via flange 308 to a conical lower portion 306 having an autoclave outlet 310. In some cases, the heating coil 108 is formed as a half tube that is welded directly to the outer surface of the container body. As noted above, the container body can be a coated container that includes a first wall 402 and an inner coating 404.

As part of the heating assembly, the transition conduit 124 can fluidly connect the fluid outlet 122 to the transition chamber 118. The transition chamber directs the heated fluid into the half tube heating coil 108 as shown by fluid flow path 406. Thus, the heating assembly can be a composite heating system that effectively uses a heating jacket under the polymerization autoclave and a more conventional half-tube heating coil for improved performance.

The heating jacket described above can be advantageously used in the original construction of a polymerization autoclave. However, such heating jackets are particularly useful for repairing and/or improving the reliability of existing autoclaves. Thus, Figure 5 shows a method 500 of repairing a polymeric autoclave to which an external heating coil is attached to an outer surface. In such cases, a standard heating coil (e.g., a half pipe) may extend from the bottom of the outer surface of the autoclave to the upper portion of the outer surface. Typically, the heating coils are wound up at least halfway along the outer surface. In any case, the portion of the heating coil may begin to break due to low cycle fatigue. In most cases it is associated with the initial portion of the coil where the heating fluid is at a maximum (e.g., when the temperature differential is also maximized during temperature transitions). When the heating coil has a weakened or leaking section below the outer surface of the autoclave, such defects can be effectively repaired using the method of the present invention. The method can include removing a leak section 510 of the heating coil from below the outer surface of the autoclave. The functional portion of the heating coil remains in the upper portion of the outer surface with the intact heating coil section. The leaking section can be removed using any suitable technique that does not adversely affect the container body or adjacent welds or joints. In an alternative case, the leak section can be removed by grinding. Other mechanical techniques may also be used, such as, but not limited to, plasma cutting, torch cutting, metal cutting saws, laser cutting, and the like. The exposed surface can then be typically cleaned. Cleaning can include one or more of the following steps: polishing, washing, surface treatment, and surface coating.

After the exposed outer surface is obtained, the heating jacket can be attached to the lower portion of the outer surface to form a closed chamber 520. In most cases the heating jacket can be attached by welding. Non-limiting examples of welding techniques include gas shielded tungsten arc welding (GTAW), shielded metal arc welding (SMAW), gas shielded metal arc welding (GMAW), and the like. The weld joint strength can be increased using overlapping misaligned weld deposits when establishing welded joints. In addition, the welded joint can be a fully permeable weld (ie, as opposed to a spot weld or a partially permeable weld).

Referring again to Figure 5, the enclosed chamber can be fluidly coupled 530 to the intact heating coil section. This may involve connecting a transition duct and/or a transition chamber to connect the heating jacket to the heating coil. As with the heating jacket, the transition chamber or other connections can be tightened using welding techniques. These welding techniques provide long life over a wide range of operating conditions. In any event, the connectors can be tightened to prevent the heating fluid from leaking from the external heating assembly and withstanding typical operating conditions. In this manner, the polymerization autoclave can be repaired or modified by providing a composite external heating assembly.

The heating jacket and heating assembly described herein provide for efficient heat transfer while also minimizing or eliminating the chance of low cycle fatigue. Thus, a polymeric autoclave incorporating such external heating devices provides extended life, higher reliability, and a more uniform heat distribution.

Although the subject matter has been described in language specific to structural features and/or operation, it is to be understood that the subject matter defined in the appended claims Rather, the specific features and acts described above are disclosed as examples of the scope of the invention. Many modifications and other configurations are conceivable without departing from the spirit and scope of the technology.

100‧‧‧Polymerized autoclave

102‧‧‧Composite external heating unit/external heating unit/heating unit

104‧‧‧heating jacket/autoclave heating jacket

106‧‧‧ autoclave container body/container body

108‧‧‧Heating pipe/heating coil

110‧‧‧ upper first import

112‧‧‧second import

114‧‧‧pressure relief valve

116‧‧‧ outer surface

118‧‧‧Transition room

120‧‧‧ Jacket fluid inlet/fluid inlet

122‧‧‧ Jacket fluid outlet / fluid outlet

124‧‧‧Transformation pipeline

Claims (20)

An autoclave heating jacket comprising: a heating fluid ring having an outer wall, an upper contact surface, and a lower contact surface, forming a closed chamber when engaged with an outer surface of the autoclave; oriented to pass through the outer wall and capable of heating Fluid is directed to a fluid inlet in the enclosed chamber; a fluid outlet oriented to pass through the outer wall and capable of directing the heating fluid out of the closed chamber; and a plurality of fluid flow baffles oriented within the enclosed chamber and grouped State to direct the heating fluid along the predetermined path within the enclosed chamber. The autoclave heating jacket of claim 1, further comprising a transition chamber fluidly coupled to the fluid outlet and configured to direct flow into a half-tube heating coil attached to the outer surface of the autoclave. The autoclave heating jacket of claim 2, wherein the transition chamber is fluidly connected to the fluid outlet via a conduit. The autoclave heating jacket of claim 1, wherein the outer wall has an annular shape. The autoclave heating jacket of claim 4, wherein the upper contact surface is an annular ridge defining a top plate of the ring. The autoclave heating jacket of claim 4, wherein the lower contact surface is an annular flange defining a bottom plate of the ring. The autoclave heating jacket of claim 1, wherein the fluid inlet and the fluid outlet are in close proximity to each other, and the plurality of fluid flow baffles include a dividing baffle oriented between the fluid inlet and the fluid outlet to The outer surface of the autoclave is guided through the closed chamber to guide the heating fluid. The autoclave heating jacket of claim 1, wherein the plurality of fluid flow baffles comprises An alternating upper baffle and a lower baffle distributed along the enclosed chamber such that the predetermined flow path is a serpentine fluid flow path. The autoclave heating jacket of claim 8 wherein the serpentine fluid flow path varies horizontally and vertically. A polymerization autoclave having a composite external heating assembly, comprising: an autoclave container body having an internal reaction chamber and an outer surface, the outer surface including an upper portion and a lower portion; and a heating jacket attached to the lower portion to form a closed chamber, The enclosed chamber has a plurality of fluid flow baffles configured to direct heating fluid within the enclosed chamber and around the lower portion along the winding path; and a heating conduit wound and attached to the upper portion, the heating conduit having a plurality of surrounding An upper wrap and fluidly coupled to the heating jacket such that the heating fluid can circulate through the closed chamber and the heating conduit to transfer heat to the internal reaction chamber, wherein the heating jacket and the heating conduit form the composite External heating assembly. The polymerization autoclave of claim 10, wherein the container body is a coated container. A polymeric autoclave according to claim 10, wherein the heating jacket covers from 3% to 40% of the outer surface. A polymeric autoclave according to claim 10, wherein the heating jacket is a ring having an annular vertical outer wall joined to the bottom plate and the top plate, the bottom plate and the top plate together bringing the heating fluid against the lower portion of the outer surface. The polymeric autoclave of claim 10, wherein the plurality of fluid flow baffles are oriented to define a serpentine fluid flow path. A polymerization autoclave according to claim 10, wherein the heating pipe is a half pipe which is directly welded to the outer surface of the autoclave. The polymerization autoclave of claim 10, further comprising a transition chamber that fluidly couples the heating jacket to the heating conduit. A method of repairing a polymeric autoclave having an external heating coil attached to an outer surface, the heating coil having a weakened or leaking section below the outer surface of the autoclave, the method comprising: from the autoclave The lower portions of the outer surface remove the weakened or leaking sections of the heating coils such that the intact heating coil section remains above the outer surface; the heating jacket of claim 1 is attached Connecting the lower portions of the outer surface to form a closed chamber; and fluidly connecting the closed chamber to the intact heating coil portion. The method of claim 17, wherein the heating jacket is attached by welding. The method of claim 17, wherein the heating jacket comprises a chromium-molybdenum steel alloy. The method of claim 17, wherein the plurality of fluid flow baffles are oriented within the enclosed chamber to define a serpentine flow path for the heating fluid.