FR2802216A1 - HANDLING DEVICE FOR CORROSIVE CHEMICALS - Google Patents

Abstract

The invention relates to a device for handling corrosive chemicals (100, 200, 200), comprising inner channels (101, 102, 103, 201, 301) for circulating said chemicals. The device is characterized in that certain parts (111, 112, 211, 212, 311, 312) thereof comprise a protective coating (121, 122, 221, 222, 321, 322) and in that said coating contains at least one layer of a material containing at least one fluorinated polymer capable of resisting said chemicals. Said fluorinated polymer is preferably a poly(tetrafluoroethylene) (PTFE) or a poly(ethylene/chlorotrifluoroethylene) (ECTFE). The invention solves the problem of providing corrosion resistance to devices such as these which operate in extremely aggressive media.

Description

TECHNICAL FIELD OF THE INVENTION The invention relates to devices for handling chemicals intended for <B> </ B> </ B> </ B> B> to the chemical industries. In particular, it relates to mixers, processing devices and conveying devices suitable for handling highly corrosive products such as concentrated acids or bases. In the present application, the term "handling device" refers in particular collectively, mixers, processing devices and routing devices.

 <U> state of the art </ U> The chemical industries use many devices to handle, convey, treat and / or handle chemicals. Many of these products are highly corrosive and therefore require means to withstand <b> their chemical attack.

In particular, chemical mixers are passive devices which make it possible to mix different products, generally in liquid or gaseous phases. Dilators (or "diluers") of strong acids are typical examples of chemical mixers.

Most often, chemical mixers also include means for conveying the resulting mixture to a specific destination. Typically, chemical mixers are used to mix two corrosive fluids and to convey the mixture to a reservoir.

In order to ensure good corrosion resistance, devices intended for the chemical industries are generally made of stainless steel. However, the known devices have limited lifetimes, which require to change regularly. The devices therefore become consumable products that burden operating strokes, both by their own cost as the costs involved interventions and production stops.

The Applicant has therefore sought economic solutions to solve the problem of resistance to corrosive devices for handling corrosive chemicals.

<U> Description of the invention </ U> The subject of the invention is a device for handling corrosive chemical products comprising internal pipes for circulating said products, characterized in that specific parts of the device are coated with at least a protective layer comprising at least one fluoropolymer suitable for resisting said products.

The invention also relates to a junction of corrosive chemical handling devices characterized in that specific parts of said junction are coated with at least one protective layer comprising at least one fluoropolymer capable of <B> to </ B > resist the said products.

<U> Figures </ U> Figure <B> 1 </ B> illustrates, in longitudinal section, a corrosive chemical handling device of the prior art comprising a mixer and conveying means.

Figures 2 <B> to 7 </ B> are relative <B> to </ B> the invention. FIG. 2 illustrates, in longitudinal section, devices for handling corrosive chemical products according to the invention: a mixer (FIG. 2 and two conveying devices (FIG. 1B) and <B> 1 </ B> c).

Figure <B> 3 </ B> illustrates, in longitudinal section, an assembled handling device comprising a mixer and a conveying device formed of two sections, the first of these being provided with mechanical reinforcement means.

FIG. 4 illustrates a routing device according to the invention provided with means of mechanical reinforcement, comparable to that of FIG. 2a: <B>: </ b> a) in longitudinal section <B>; b) </ B> truncated cross-section in plane A-A.

Figure <B> 5 </ B> illustrates, in longitudinal section, a routing device according to the invention, comparable <B> to </ B> that of Figure 2c.

Figure <B> 6 </ B> illustrates in longitudinal section, an end seal junction according to the invention.

Figure <B> 7 </ B> illustrates, in cross-section, a bolted joint according to the invention. In figures, the arrows indicate the normal flow directions of the fluids.

As illustrated in FIG. 1, prior art chemical mixers of the prior art typically comprise at least two inlet lines. (2, <B> 3), </ B> mixing zone (4), at least one outlet pipe <B> (5) </ B> and joining means <B> (6, 7, < / B> <B> 8). </ B> In most cases, mixers are equipped with <B> (10) </ B> means to route fluids to a <B> (9) </ B> port. away from the mixing zone (4). Mixers are often used to mix two different fluids and to route the resulting mixture to a specific place of use or storage. Typically, the mixer can be used to dilute a strong acid in a neutral liquid and to deliver the diluted acid to a <B> (1 5) reservoir. </ B> In this case, the <B> outlet pipe ( 5) </ B> of the mixer is fit <B> to </ B> fit into an opening (12) of the tank <B> (</ B> tank <B> (15) </ B> and the mixer <B> (1) </ B> being provided with fixing means and / or junction <B> 11) </ B> adapted to assemble rigidly and tightly.

<U> Detailed Description of the Invention </ U> The device for handling corrosive chemicals <B> (100, </ B> 200, <B> 300) </ B> according to the invention comprises internal pipelines <B> (101, </ B> 102, <B> 103, </ B> 201, for circulating said products, and is characterized in that specified portions <B> (111, 11 </ B> 211 , 212, <B> 3 11, 3 </ B> 12) of said device comprise a protective coating (121, 122, 221, 222, <B> 321, 322) </ B> and that said coating comprises at least less than one layer a material comprising at least one fluoropolymer capable of withstanding said products, Preferably said fluorinated polymer is a poly (tetrafluoroethylene) (PTFE) a poly (ethylene / chlorotrifluoroethylene) (ECTFE).

The handling device generally comprises partitions <B> (131, 132, 1, <B> 23 </ B> 2, <B> 3 3 1), </ B> which are typically made of a metal such as stainless steel. These partitions generally form the inner channels <B> (101, </ B> 102, <B> 103, </ B> 201, <B> 30 </ B> of the device. Said determined parts comprise specific parts of the partitions internal and / or external portions of these partitions may be coated with said polymer, that is to say that said determined portions comprise internal and / or external parts of said partitions.

The device according to the invention can be a mixer (100), a routing device (200, 300) or any combination thereof. The conveying device may form, in whole or in part, an extension of the mixing zone <B> (1 </ B> 04) and / or the outlet pipe <B> (103). </ B>

The chemical mixer <B> (1 00) </ B> according to the invention, which typically comprises at least two inlet lines <B> (1 0 1, </ B> 102), a mixing zone <B > (l </ B> 04), at least one output pipe <B> (103), </ B> and connecting means <B> (105, 106, 1 </ B>) is characterized in that determined portions <B> (111, </ B> 112) of said sliver comprise a protective coating (121, 122) and in that said coating comprises at least one layer of a material comprising at least one fluoropolymer capable of B> to </ B> corrosive products, such as poly (tetrafluoroethylene) (PTFE) or poly (ethylene / chlorotrifluoroethylene) (ECTFE). Preferably, said predetermined portions comprise specific portions of the inner surfaces <B> (11 1 </ B> 12) of the pipes exposed to the corrosive fluids, and preferably all of the inner surfaces are coated with said coating.

The mixer according to the invention can be assembled to at least one conveying device (200, 300), which is preferably according to the invention, and which can form , in any part, an extension of the mixing zone <B> (l </ B> 04) and / or the outlet pipe <B> (103). </ B> The mixer and the (or each) may be joined by means of tight assembly <B> (107, </ B> <B> 206, 207, 3 </ B>) which assembly means preferably comprise junction means according to the invention .

The mixer may consist of several separate parts or sections <B> (l </ B> 4 <B> 1, 1 </ B> joined by means of assembly (143) sealed, which assembly means comprise of preferably joining means according to the invention.

The conveying device (200, <B> 300) </ B> according to the invention, which comprises at least one inner pipe (201, <B> 301) </ B> and, generally, at least one joining means <B> (206, 207, 306), </ B> is characterized in that specified portions (211, 212 <B> 311, 312) </ B> of said device comprise a protective coating (221, 222, < B> 321, 322) and that said coating comprises at least one layer of a material comprising less than one fluoropolymer suitable for resisting products. corrosive, whether poly (tetrafluoroethylene) (PTFE) or poly (ethylene / chlorotrifluoroethylene) (ECTFE). preferably, said determined portions comprise specified portions of the inner (211, <B> 311) </ B> and / or outer (212, <B> 312) </ B> surfaces of the pipeline exposed to the corrosive fluids. More preferably, the entire inner surface is coated with the protective coating. In order to facilitate their use, and in particular their placement, the conveying means can form separate devices, of generally simple shape, which comprise joining means for assembling them together and / or connecting them to </ B> a mix.

Mixers <B> (100) </ B> and routing means (200, <B> 300) </ B> can be combined in different ways from <B> to </ B> form a complete device .

The routing device may comprise mechanical reinforcing means, such as a second envelope (B) (232) and / or gussets or reinforcements (241). These means make it possible to stiffen the device and to make it more resistant to the mechanical stresses associated with the agitation of the fluids.

The conveying device may comprise heating means, in which case only the surfaces exposed to the corrosive fluids are preferably coated with the protective coating. Typically, the heating means comprise a pipe <B> (250) </ B> juxtaposed <B> to </ B> its partition <B> (231) </ B> and adapted <B> to </ B> be supplied with heat transfer fluid. The portions (211, 212) of this line exposed corrosive fluids preferably comprise a protective coating. The heat-up and mechanical reinforcement means may have common elements, as illustrated in FIGS. 2B and 4. For example, the gussets or reinforcements may be located in the pipe. <B> (250), </ B> in which case they may include openings (not shown) to allow the flow of heat transfer fluid.

The routing device according to the invention may comprise a free end <B> (307) </ B> which generally corresponds to an outlet orifice for the fluids conveyed by the device. This free end preferably comprises a so-called "end" waterproof anointing (400), such as that illustrated in detail in FIGS. 5 and 6. end according to the invention is characterized in that specific parts (402) thereof comprise a protective coating (401) and in that said coating comprises at least one layer of a material comprising at least one fluoropolymer capable of B> to </ B> resist <B> to </ B> corrosive chemicals, such as poly (tetrafluoroethylene) (PTFE) or poly (ethylene / chlorotrifluoroethylene) (ECTFE). In the preferred embodiment of this junction, the coating (40 <B> 1) </ B> is an extension of the inner <B> (321) </ B> and outer <B> (322) </ B > a handling device according to the invention. The coating (401) may be continuous, i.e., the inner and outer coatings form a continuity, or welded (over a length L) tightly.

The bolted junction <B> (500) </ B> according to the invention is characterized in that specific portions <B> (505, 506, 507, 508) </ B> thereof comprise a protective coating < B> (501, 502,, </ B> 504) and in that said coating comprises at least one layer of a material comprising at least one fluoropolymer capable of <B> to </ B> resist <B> to < / B> corrosive chemicals, such as poly (tetrafluoroethylene) (PTFE) or poly (ethylene / chlorotrifluoroethylene) (ECTFE). Preferably, this coating is interposed between two opposing joining surfaces <B> (505, 506, 507, 508) </ B> of joining means <B> (509, 510, 511). </ B> each <B> coating (501, 502, 503 </ B> 504) advantageously forms a continuous bond with the or each inner <B> 1, 321) </ B> or outer (222, <B> 322) coating < / B> corresponding device according to the invention. Typically, an inner or outer liner will have a protruding portion <B> at the end of the conveying device, to the right of the junction means, which will be folded in a <B> manner to </ B>. contact with the surface of one of said means and <B> to </ B> can be sandwiched between two junction surfaces.

The coating thickness is chosen so as to provide sufficient protection against the corrosivity of the products. It is typically between <B> 1 </ B> and <B> 10 </ B> mm. In a variant of the invention, the surfaces of the handling device and / or the junction comprise complementary coatings <B> (601, </ B> 341, 342), which may be PTFE or other material such as ECTFE, and which may cover certain different parties. Some particular parts can thus be coated two or more layers of the same material or different materials. The layers may act in a complementary manner, for example, a layer of material having good resistance to given corrosive products, but poor adhesion to <B> surfaces. to protect, can be supplemented by an underlying layer of strong adhesion.

The handling devices according to the invention can be advantageously used for handling, and especially for mixing or dilution or conveying, strong acids, such as concentrated sulfuric phosphoric acids, or strong bases, such as concentrated sodium hydroxide.

The coatings can be applied by any known means. For example, PTFE coatings may be applied mechanically and ECTFE coatings may be applied by dipping the specified portions into a melt of ECTFE bath or by pulverulent deposition followed by a thermal melting treatment <B> at 300 ° C. </ B>

<U> Advantages of the invention </ U> The invention provides an economical solution to the problem of the resistance <B> to </ B> the corrosion of such devices with highly aggressive media.

Claims (1)

<B> CLAIMS </ B> <B> 1. </ B> Corrosive chemical handling device <B> (100, </ B> 200, <B> 300) </ B> including internal piping < B> (101, </ B> 102, <B> 103, </ B> 201, <B> 30 </ B> to circulate said products, characterized in that specific parts <B> (11, 11 </ B> 2, 211, 212, <B> 311, 312) </ B> of said device comprise a protective coating (121, 122, 221, 222, <B> 321, 322) </ B> and said coating comprises less a layer of material comprising at least one fluoropolymer suitable for resisting said products 2. A device according to claim 1 selected from the group consisting of mixers <B> 00), </ B> routing means (200, <B> 300), </ B> and combinations thereof. <B> 3. </ B> Device according to claim 1, wherein said determined portions comprise specific portions of said pipes B> 103, </ B> 201, <B> 301). </ B> 4. A device according to any one of claims 1 to 3, characterized in that said determined parts comprise inner surfaces <B> (l 1, 1 </ B> 12, 21 <B> 1, </ B> <B> 311) </ B> and / or external surfaces (212, <B> 312) </ B > exposed to corrosive fluids. <B> 5. </ B> Handling device according to any one of claims <B> 1 to </ B> 4, characterized in that said fluoropolymer is a poly (tetrafluoroethylene) (PTFE) or poly (ethylene / chlorotrifluoroethylene) (ECTFE). <B> 6. </ B> Manipulation device according to any one of claims <B> 1 <I> to 5, </ I> </ B> characterized in that it comprises a complementary coating (34 <B >, </ B> 342). <B> 7. </ B> Device according to claim 6, characterized in that the additional coating is a polytetrafluoroethylene (PTFE) or a poly (ethylene / chlorotrifluoroethylene) (ECTFE) . <B> 8. </ B> Watertight end junction characterized in that specific portions (402) of said junction comprise a protective coating (40 <B> 1) </ B> and that said coating comprises at least one at least one layer of a material comprising at least one fluoropolymer adapted to withstand corrosive chemicals. <B> 9. </ B> Junction according to claim 8, characterized in that the coating (401) the extension of the internal <B> (321) </ B> and external <B > (322) </ B> of a device according to one of the claims <B> 1 to 7. <B> 10. </ B> Junction according to claim <B> 8 </ B> or <B> 9, </ B> characterized in that said polymer is poly (tetrafluoroethylene) (PTFE) or poly (ethylene / chlorotrifluoroethylene) (ECTFE). <B> 11. </ B> Bolted joint <B> (500) </ B> characterized in that specified portions <B> (505, </ B>, 507, 508) </ B> of said junction comprise a protective coating <B> (501, </ B> <B> 502, 503, </ B> 504) and in that said coating comprises at least one layer of a material comprising at least one polymer Fluoride suitable for resistant to corrosive chemicals. Junction according to claim 11, characterized in that the or each coating <B> (501, 502, 503, </ B> 504) forms a continuous bond with the or each internal lining ( 221, <B> 321) </ B> or external (222, <B> 322) </ B> corresponding device according to one of claims <B> 1 to 7. </ B> <B> A joint according to claim 11, wherein said fluorinated polymer is a polytetrafluoroethylene (PTFE) or a poly (ethylene / chlorotrifluoroethylene) (ECTFE). . 14. Junction according to any one of claims <B> 8 to 13, </ B> characterized in that it comprises a complementary coating <B> (60 1). </ B> <B> 15. </ B> Junction according to any one of claims <B> 8 to </ B> 14, characterized in that the complementary coating <B> (601) </ B> is a polytetrafluoroethylene (PTFE) or a poly (ethylene / chlorotrifluoroethylene) (ECTFE). <B> 16. </ B> Use of a device according to one of claims <B> 1 to 7 </ B> or a joint according to one of claims <B> 8 to </ B> to handle strong acids or strong bases. <B> 17. </ B> Use of a device according to one of claims <B> 1 to 7 </ B> or a joint according to one of claims <B> 8 to 15 </ B > for mixing or dilution operations or for conveying strong acids or strong bases.