WO2020157343A1

WO2020157343A1 - Method for building mechanically resistant tanks onsite and tank obtained

Info

Publication number: WO2020157343A1
Application number: PCT/ES2019/070050
Authority: WO
Inventors: José Luis PEÑA GÓMEZ
Original assignee: Peña Gomez José Luis
Priority date: 2019-01-30
Filing date: 2019-01-30
Publication date: 2020-08-06

Abstract

Method for building chemically resistant tanks onsite and tank obtained, comprising: - building/preparing an outer casing (2); - building a permeable-mesh (4) interstitial chamber (3); - building an inner substrate of flexible and very thin metal-plastic laminate (5), applying a vacuum to the interstitial chamber (3) so that it adopts the inner shape of the casing (2), covering the whole; - and applying protective and reinforcing resin (8) of isocyanate and a complex of up to nine different products, such as polyol, carbohydrates, alcohols and others, with great adherence and chemical resistance to PPL additives and biofuels, pressure-sprayed at a certain temperature on the flexible, thin laminate (5), thereby increasing its thickness and mechanical resistance so it remains in place after ceasing to apply the vacuum.

Description

PROCEDURE FOR THE CONSTRUCTION OF TANKS

CHEMICALLY RESISTANT AND IN ITS OWN LOCATION, AND

TANK OBTAINED

D S S C R I P C I O N OBJECT OF THE INVENTION

The invention, as expressed in the statement of the present specification, refers to a procedure for the construction of chemically resistant tanks and in its own location, and to the tank obtained, providing, to the function for which it is intended, advantages and characteristics. , which are described in detail below, which represent a remarkable novelty in the current state of the art.

More specifically, the object of the invention focuses on a procedure for carrying out the construction of a liquid storage tank, specifically liquid petroleum products or PPL and biofuels, with highly improved resistance to the chemical aggression produced by said products against to which currently existing tanks offer, which is built on the site of use, preferably within an existing tank to which it replaces, so that it is used as an external envelope of the new tank, essentially comprising the conditioning of said envelope, the construction of an interstitial chamber and the construction of a new interior wall which, in an innovative way, is formed from a flexible laminate of plastic and metal that is introduced through the mouth of the existing tank or external envelope and adapts to the shape of its interior by means of vacuum application, and a protective layer of resin and special reinforcement, with high adhesion and resistance to chemical aggression, which is subsequently applied to the substrate that constitutes the aforementioned laminate and which is what makes it chemically resistant to PPL additives and biofuels.

FIELD OF APPLICATION OF THE INVENTION

The field of application of the present invention is framed within the sector of the industry dedicated to the manufacture and / or transformation of liquid storage tanks, focusing particularly on those intended to contain PPL's and biofuels.

BACKGROUND OF THE INVENTION

The PPL ^' s (liquid petroleum products), generically diesel and gasoline, like any other product transformed and influenced by technology, evolve. A consequence of this evolution are the so-called biofuels, which are the fuels that imitate petroleum derivatives, basically gasoline and diesel fuels, produced with petroleum distillates to which alcohols and esters obtained from organic materials are added by different processes.

Biofuels and liquid biofuels are being applied 100% but they are also added to a lesser or greater degree, forming a percentage of PPL ^' s in general.

Therefore, fuels and liquid fuels usually contain percentages of alcohols and esters, as well as MTBE (Methyl-Ter-Butyl-Ether) that replaced lead to improve octane rating. All these additives are characterized by being very chemically aggressive due to their condition as solvents. Consequently, the tanks intended for the storage of this type of products should also evolve and adapt their resistance to these new solvents incorporated in the PPL's. On the other hand, different procedures are known in the state of the art for reinforcing and transforming tanks of the type that are concerned here. In fact, the applicant himself owns various documents that disclose some of these procedures, which, however, are not intended to provide them with the necessary resistance they now require.

To give them chemical resistance, we gave them a chemical protection layer (top coat) with pure resin, but it only resists 80% and cannot be very thick due to the resin's own rheology and thixotropy.

Specifically, as more relevant and closer to the present invention, it is worth mentioning document ES2430197A1, which discloses a "Procedure for transforming an existing single-walled tank into an intrinsically safe double-walled tank", in which, essentially, contemplates the construction of an interstitial chamber, between the existing wall with a reinforcement and the new wall to be formed, placing a mesh that allows air to be extracted from a vacuum bag, and document ES 2540938, in which a “procedure for the application of GRP layers with a vacuum technique in liquid storage tanks ”that includes the introduction of a bag in the tank that, prior to the vacuum process to form the GRP layer, is filled with air to behave as a balloon to fit the inside walls of the tank. However, roughly speaking, both documents refer to the construction of the new composite walls inside the tanks by applying conventional resin infusion processes on previously placed fabrics.

The objective of the present invention is, therefore, to develop a new procedure that, partially taking advantage of the technology of the procedures already known, but introducing new elements, allows the construction of new tanks inside existing tanks or the construction of totally new tanks on their own location capable of withstanding chemical attacks of the new types of PPL that currently must contain.

On the other hand, and as a reference to the current state of the art, it should be noted that, at least on the part of the applicant, the existence of no other procedure for the construction of a chemically resistant tank and on its own site or the tank obtained is unknown. or another similar invention that presents technical, structural and constitutive characteristics equal to or similar to those presented by the process and tank claimed herein.

To better understand the advantages of the proposed procedure compared to what is already known, it is useful to make a small reminder of the current panorama of tank construction and existing procedures.

The oldest tanks are ceramic to store wines and oils. From the 18th century the tanks began to be built using steel sheets joined by rivets and later, already in the 20th century by welding.

From 2 ^{to the} middle of the 20th century they began to be built with fiberglass-reinforced resins (fiberglass-reinforced plastic, GRP in Spanish and FRP in English) although most have continued to be made of metal.

Up to a volume of about 100 m ^3, the most common was its construction in the workshop and its subsequent transportation to the site. For larger volumes they have been built on site. GRP tanks, until today, are low volume and have always been built in workshops.

It is also the two half last century when they begin to build tanks high density polyethylene (HDPE PEAD-) either by rotational molding or injection-blowing technology, the latter being the most widely used due to its higher productivity. However, this technology is limited by the application of the pressure to be applied to the mold (by the law of the surface-volume relationship), currently reaching a maximum of 5000 L of volume per tank. Its lower weight compared to steel, as well as good behavior and lower manufacturing cost have led to the complete replacement of steel tanks of less than 5 m ³ , except for those to be installed underground. Therefore, the current landscape of tanks is as follows:

MANUFACTURED MATERIAL VOLUME INSTALLATION

£ 3,000 L PEAD TALLER AEROS

£ 50,000 L PRFV UNDERGROUND / AIR WORKSHOP

£ 100,000 L STEEL UNDERGROUND / AERIAL WORKSHOP

³ 100,000 L STEEL WORK AERIAL

On the other hand, the current panorama of the facilities is as follows:

The location of the tanks is related to the product they store. To store highly flammable fuels or liquids, the most common rule is that they be installed buried underground.

Obviously, all gas station and service station tanks, in most countries, are buried.

When repairing the steel tanks, when they have lost their tightness, they use an accessible interior coating with GRP by means of wet applications (by hand). This task has two major drawbacks: - that, while carrying out the work, the resins emit volatile organic compounds (VOC ^' s - VOC ^' s) which, in addition to damaging the atmosphere, are very harmful to operators, so they must work with personal protective equipment - EPI ^' s; and

- that, in addition, when polymerizing they emit heat and, in a confined space, make it an extremely uncomfortable and dangerous work environment for the workers' health, so that this activity is classified as the one with the highest occupational risk.

These problems have been solved by the applications of VI P - Vacuum infusion process technology, on which the applicant himself has several patents.

The resins that have been used in repairs since the 80 ^' s of the last century are generically called thermoplastic, polyester, vinyl ester and epoxy resins. However, these resins have a maximum of 79% resistance to chemical attack from the current additives of all fuels, especially alcohols. In contrast, thermosetting resins have a higher chemical resistance, although they have the disadvantage that they are more difficult to polymerize since they require heat and, in the event of fire, emit highly poisonous fumes.

So far, in summary, the overall picture is as follows:

The construction of new tanks, be they steel, HDPE or GRP, is carried out in the workshop.

The repair and / or reform of existing tanks is carried out by means of GRP applications on site, either by wet route or by VI P. applications. The resins that are applied partially resist the chemical attack of the new fuels.

Therefore, the new procedure proposed by the present invention solves these problems.

EXPLANATION OF THE INVENTION

The procedure for the construction of chemically resistant tanks and in their own location, and the tank obtained that the invention proposes, are configured, therefore, as a remarkable novelty within its field of application, since according to its implementation and exhaustively The aforementioned objectives are satisfactorily achieved as being suitable, the characterizing details being that make it possible and that distinguish it conveniently included in the final claims that accompany the present description.

More specifically, what the invention proposes, as previously pointed out, is a procedure for building liquid storage tanks, particularly PPL's and biofuels, with highly improved resistance compared to current tanks, which constitutes a fully new advantageously built on the site of use, taking advantage of an existing conventional tank to which it replaces, and which becomes the external envelope of the new tank, which is a factor of environmental protection as it allows applying circular economy criteria , without ruling out the use of another type of external envelope, either new construction or taking advantage of an existing one.

For this, this procedure is based, essentially, on the following phases:

- An initial phase of construction or preparation of the external envelope, in case of being an existing tank that, based on already known processes, includes the emptying, degassing, cleaning and degreasing of the existing tank, as well as in the repair and homogenization of sudden changes in its geometry or small defects in welds , if any, by applying repair putties.

- A construction phase of the interstitial chamber that, also based on processes already known for the formation of double-walled tanks, for example, as described in document ES2430197A1, comprises the application, on the inside face of the aforementioned external envelope , of a highly permeable mesh type fabric that allows the circulation of a fluid, normally air, through it with little resistance.

- A phase of construction of an interior substrate, constituent of the wall of the new tank, which, now in a totally innovative way, in addition to the introduction, through the mouth of the envelope when it has it because it is already a tank existing, it includes the application of the flexible and very thin laminate that, made up of one or several laminar pieces of a combination of metal and plastic that are joined and / or welded together, is made as a kit to be introduced into the entire set already the right measure to configure said new wall and that, being flexible and very thin, it adopts the interior shape of the envelope, when the vacuum is made in the interstitial chamber, so that it covers the entire interior of said existing envelope or tank and adapts to the shape it has.

- And a phase of application of the protective and reinforcing resin, which, also in an innovative way, consists of a special bi-component resin, which is highly adherent to the substrate and highly chemical resistant to the additives of the PPL's and biofuels, and that, to achieve these qualities, it is applied sprayed under pressure with a reactor at a certain temperature, specifically with a reactor that sprays it at 150 bar pressure and more than 60 ° C temperature, on the substrate, that is, on the metal-plastic laminate, giving this, in addition to the protection against chemical attacks, an increase in its thickness that will provide it with the mechanical resistance that, being very fine, does not have to that it remains in its position, adapted on the inside of the tank, when it stops applying the vacuum in the interstitial chamber that has been used to shape it.

Preferably, said increase in thickness in the flexible laminate that provides the protective and reinforcing resin is at least 2 mm, which is achieved by applying at least four layers of said resin pulverized with the reactor to more than 60 °.

For its part, the aforementioned resin, which as noted above is distinguished by being especially chemically resistant to hydrocarbons, while the hitherto known resins, polyester, vinyl ester and epoxy, are only partially resistant, is a two-component resin, Isocyanate on the one hand and a complex of different products, up to nine, which we generically call Polyol, carbohydrates, alcohols and others. This resin is a resin of the family of PU - U (polyurethane - high urethane)

Specifically, said products of the second component, expressed through the numerical identification CAS (Chemical abstraéis Services), are as follows and in the indicated percentages: CAS No. 9082-00-2 .4.0%

CAS No 25791-96-2 ... 20.0%

CAS No 25791-96-2 ... 46.0%

CAS No 31568-06-6 ... 21, 0%

CAS No. 77-58-7 .5.50%

CAS No. 1344-28-1 .2.5%

CAS No 13463-67-7 .4.5% Defoamer .. 0.5%

Adherent 0.5%

Dispersing 0.5% With all this, the advantages provided by the recommended procedure and the tanks that it allows to obtain in its own location are verified, compared to what has been done so far in this field.

In recent years, it has continued to improve VIP technology and has obtained a new complementary technology to the previous one, whose origin and foundation is as follows:

An improved resin. - One of the EU's priorities is the achievement of the Single Market. To this end, the Commission, as the managing body of EU policy, orders the elaboration of TECHNICAL STANDARDS that promote detailed and rigorous compliance with the European Regulations, formerly Directives, that promote and promote the Single Market.

- The technical standards derived from the Commission's mandates are called "harmonized" and cover a wide range of products and materials, therefore they are very generic. - For the protection of industrial devices and plants, technical standards speak of “organic materials” (resins) which are classified into two main groups, Thermosets and Thermoplastics, both with different characteristics and qualities. Thus, GRP applications are made with thermoplastic resins due to its ease of application and consequent polymerization. However the downside is that they are not 100% resistant to current fuel additives.

In contrast, thermosetting resins are resistant, but for their proper polymerization they require application procedures that until now were impossible to carry out outside the workshop.

The resin used can be considered as a hybrid resin between the two families, so that it can be applied under certain conditions and with special tools to meet the demands of the work required. This application must be done by “spraying” the resin at a temperature greater than 60 ° C and at a pressure greater than 150 bar.

The new Tanks up to 100 m ³

Both VIP (infusion) and DWT (spray) technology enable tanks to be built on site. That is why we say that the procedure allows new tanks to be built on their own site, both inside pre-existing buried tanks and in other circumstances.

Most of the countries called "emerging economies" (previously said to be underdeveloped), do not have basic industries such as steel or good roads, so storage tanks are priced much higher than in developed countries. The possibility of building the tanks on their own site with accessible and easy-to-apply technologies such as infusion and spraying come to solve the previous barriers.

In summary, the applications of a combination of resin infusion and spraying technologies provided by the process of The present invention enables a new and important development of the tank construction industry, both for the improvement and updating of existing tanks, incorporating these into the Circular Economy, and opening new and important possibilities for developing countries by allowing them access to these goods in better conditions, especially economic.

Construction of new tanks on site using the combined application of infusion and resin spraying techniques

The construction, therefore, of new tanks of composite materials (composite) that constitute an important advance over those of GRP that have been built so far, both due to their characteristics of mechanical and chemical resistance and because they can be built on their own site in similar safety and quality conditions as in the workshop.

The construction of composite materials (composites) by applying the VI P (vacuum infusion process) technology to the tanks, as already mentioned, is already known, but for the transformation of existing tanks from simple to double wall by means of the construction inside of a new wall.

However, VI P applications must be made with thermoplastic resins of suitable characteristics so that they can be applied by infusion. These resins are not 100% resistant to current fuel additives.

To solve this problem by means of the procedure proposed here, a final layer of pure resin is applied, without reinforcements, so that it acts as a sacrificial layer by preventing the composite from being in contact with the fuel. Regulations call this coating the chemical protection barrier and The greater the thickness, the greater the guarantee and safety of behavior.

The general classification that is given to organic resins in the regulations is that of thermoplastic and thermosets. Each family has different qualities and, above all, great differences in application techniques so that they achieve adequate polymerization and consequent behavior.

The wet coatings (manual) with the thermoplastic resins that we knew could not 100% solve the problems and, therefore, did not achieve the characteristics that were required:

- Great adherence to the substrate (greater than 6 MPa).

- 100% chemical resistance.

- Watertightness and ease of application.

These qualities have been achieved by means of a hybrid resin between thermoplastics and thermosets, a PU-U (polyurethane-high urethane) although due to its behavior it can be classified as thermoplastic.

The next problem is to ensure that your application does not cause new problems. This is achieved with strict control of the circumstances in which the application itself runs.

As a consequence of the use of this new resin, it is possible to approach the construction of new tanks on their own site since the thickness limitation barrier can be exceeded. In addition, the volume of constructions can be increased, the times of execution of work can be improved, costs can be significantly improved and a more reliable, safe and economic solution for the construction of new tanks can be reached for countries with emerging economies. DESCRIPTION OF THE DRAWINGS

To complement the description that is being made and in order to help a better understanding of the characteristics of the invention, the present specification, as an integral part thereof, is accompanied by a set of plans in which, by way of illustration and non-limiting the following has been represented:

Figure number 1.- Shows a schematic representation of a sectional view of an example of a tank obtained from the procedure for the construction of a chemically resistant tank and in its own location, object of the invention, specifically inside a tank already existing, in which its general external configuration and the arrangement and structure of the elements that it comprises internally can be seen, it should be pointed out that it has been shown in the absence of applying the resin layer, in order to show the configuration of the flexible laminate that forms the interior substrate based on pieces welded together.

And figure number 2.- Shows an enlarged view of the detail A indicated in figure 1 and representing, schematically, the section of a portion of the tank wall obtained from the method object of the invention, in which the arrangement and structure of all the elements it comprises are appreciated, which, in this case, do include the resin layer and have been represented in exaggerated proportions to facilitate their observation.

PREFERRED EMBODIMENT OF THE INVENTION

In view of the aforementioned figures, and according to the numbering adopted, a non-limiting example of a tank obtained by the procedure object of the invention can be observed, which includes the parts and elements indicated in detail in continuation. Thus, as observed in said figures, the tank (1) in question is configured, essentially, from:

- an outer shell (2), which preferably consists of an existing conventional tank, inside which an interstitial chamber (3) has been constructed from a mesh (4) of highly permeable tissue that allows the circulation of a fluid through it with hardly any resistance, usually air, which can be extracted through valves (not shown) provided for this purpose to cause a vacuum inside,

- an interior substrate of thin and flexible laminate (5), which constitutes the new interior wall of the tank (1), preferably made up of one or more laminar pieces (5a) of a combination of metal-plastic, which, when the envelope exterior (2) is already an existing tank, they are introduced into the interior of the tank (1) through the mouth (6) thereof, in any case, joined together by welding (7) and, optionally, also to the mesh (4) of the interstitial chamber (3) in at least some points, so that it covers the entire interior of the tank and adapts to the shape it has when applying the vacuum in the chamber (3),

- and a layer of protective and reinforcing resin (8), consisting of a special two-component resin, with great adhesion and high chemical resistance to the additives of PPLs and biofuels, sprayed under pressure with a reactor over 60 ° C temperature on the metal-plastic laminate substrate until its thickness is increased by more than 2 mm.

Once the nature of the present invention has been described, as well as the way to put it into practice, it is not considered necessary to make its explanation more extensive so that any expert in the matter understands its scope and the advantages derived from it, stating that: inside of Essentially, it may be put into practice in other forms of implementation that differ in detail from that indicated by way of example, and which will also achieve the protection that is provided provided that its fundamental principle is not altered, changed or modified.

Claims

1.- PROCEDURE FOR THE CONSTRUCTION OF GUIMICALLY RESISTANT TANKS AND IN THEIR OWN SITE, in particular a tank (1) applicable for the storage of liquids, specifically liquid petroleum products or PPL and biofuels, in the site of use in the interior of an outer envelope (2), and that, comprising:

- an initial phase of construction or preparation of a new outer shell (2) or consisting of an existing conventional tank, in which case it includes emptying, degassing, cleaning and degreasing the inside of said existing tank, as well as repair and homogenization sudden changes in their geometry or small defects in the welds, if any, by applying repair putties;

- and a construction phase of an interstitial chamber (3) that comprises the application, on the inside of the aforementioned external envelope (2), of a highly permeable mesh-like fabric (4) that allows the circulation of a fluid, normally air, through it with hardly any resistance, is characterized by further understanding:

- a phase of construction of an interior substrate, constituent of the wall of the new tank, which includes the application of a flexible and very thin laminate (5), and the application of vacuum in the interstitial chamber (3) so that said thin and flexible laminate (5) adopts the interior shape of the envelope (2) covering the entire interior of said envelope;

- and an application phase of a protective and reinforcing resin (8), consisting of a special two-component resin, based on Isocyanate and a complex of up to nine different products, including Polyol, carbohydrates, Alcohols and others, which is highly adherent to any substrate and highly chemical resistant to the additives of PPLs and biofuels, which is applied by pressure spraying with a reactor at a certain temperature on the interior substrate of flexible and thin laminate (5 ), and in sufficient quantity to increase the thickness of said laminate so as to provide it with sufficient mechanical strength to keep it in position, adapted on the inside of the external envelope, after ceasing to apply the vacuum in the interstitial chamber.

2.- PROCEDURE FOR THE CONSTRUCTION OF GUANCICALLY RESISTANT TANCUES AND IN THEIR OWN LOCATION, according to claim 1, characterized in that the laminate (5) that constitutes the interior substrate of the tank is made of a combination of metal and plastic.

3.- PROCEDURE FOR THE CONSTRUCTION OF TANKS

CHEMICALLY RESISTANT AND IN ITS OWN LOCATION, according to claim 1 or 2, characterized in that the laminate (5) that constitutes the interior substrate of the tank is made up of one or more laminar pieces (5a) that are welded together and / or to the mesh (4) of the interstitial chamber (3).

4.- PROCEDURE FOR THE CONSTRUCTION OF TANKS

CHEMICALLY RESISTANT AND IN ITS OWN LOCATION, according to any of claims 1 to 3, characterized in that the resin (8) is applied with a reactor that sprays it at 150 bar pressure and more than 60 ° C temperature.

5.- PROCEDURE FOR THE CONSTRUCTION OF TANKS

CHEMICALLY RESISTANT AND IN ITS OWN LOCATION, according to any of claims 1 to 4, characterized in that the resin (8) is applied until the thickness in the flexible laminate is at least 2 mm and at least in four spray layers.

6.- PROCEDURE FOR THE CONSTRUCTION OF GUIMICALLY RESISTANT TANCUES AND IN THEIR OWN SITE, according to any of claims 1 to 5, characterized in that, when the external envelope (2) is an existing tank, the laminate (5) is introduced into its interior, in its entirety and as a kit, through the mouth (6) of said existing tank.

7.- PROCEDURE FOR THE CONSTRUCTION OF CHEMICALLY RESISTANT TANKS AND IN THEIR OWN SITE, according to any of claims 1 to 6, characterized in that the two components of the resin (8) are, on the one hand, Isocyanate and, on the other hand, a complex comprising the following products: CAS No. 9082-00-2; CAS No. 25791-96-2; CAS No. 31568-06-6; CAS No. 77-58-7; CAS No. 1344-28-1; CAS No. 13463-67-7; Defoamer; Adherent; Dispersing.

8. TANK, obtained from a procedure as described in claims 1 to 7, characterized by comprising:

- an outer envelope (2), with an interstitial chamber (3) that incorporates a mesh (4) of highly permeable tissue that allows the circulation of a fluid through it with little resistance, for example, air;

- an interior substrate of flexible and thin laminate (5) that adapts to the interior shape of the exterior shell (2) covering the entirety of said interior;

- and a layer of protective and reinforcing resin (8), consisting of a special two-component resin, with great adhesion and high chemical resistance to the additives of PPL's and biofuels, sprayed in layers on the substrate made of thin and flexible laminate (5) so that its thickness increases more than 2 mm.

9. TANK, according to claim 8, characterized in that the flexible and thin laminate substrate (5) is made up of one or more pieces (5a) joined together by welding (7) and / or the mesh (4) of the interstitial camera (3) in at least some points.

10. TANK, according to claim 9, characterized in that the thin and flexible laminate substrate (5) is made of a metal-plastic combination.

11.- TANK, according to any of claims 8 to 10, characterized in that the two components of the protective and reinforcing resin (8) are, on the one hand, Isocyanate and, on the other hand, a complex comprising: CAS No. 9082- 00-2; CAS No. 25791-96-2; CAS No. 31568-06-6; CAS No. 77-58-7; CAS No. 1344-28-1; CAS No. 13463-67-7; Defoamer; Adherent; Dispersing.

12.- TANK, according to any of claims 8 to 11, characterized in that the outer shell (2) is made up of an existing conventional tank.