SK9697Y1 - Compound organic solvent for removing oil stains from hard surfaces and method for removing oil stains from hard surfaces - Google Patents

Abstract

The technical solution describes compound organic solvents for removing oil impurities from hard surfaces and a method for removing oil impurities from hard surfaces, such as the surfaces of pipelines and technological equipment or their parts. The present composite organic solvent comprises 0.1 to 35 weight percent of an organic solvent selected from the group consisting of C2 to C4 carboxylic acid esters, wherein the ester group is independently selected from the group consisting of C4 to C6 alkyl, branched C3 to C7 alkyl, or cyclohexyl; C3 to C7 linear or branched ketones, acetophenone, cyclohexanone, C1 to C2 alkyl substituted cyclohexanone; alcohols with linear or branched C5 to C12 alkyl, cyclohexanol, C1 to C3 alkyl substituted cyclohexanol; C4 to C8 alkyl ethers, ethylene glycol or its ethers, such as ethylene glycol dimethyl ether, ethylene glycol monomethyl ether, ethylene glycol butyl ether, diethylene glycol monomethyl ether, diethylene glycol diethyl ether; 1,2-propanediol or its ethers, 1,3-propanediol, triethylene glycol, hydroformylation products of 1-propene; or mixtures thereof, while the rest of the total weight of the composition is a linear or branched C4 to C22 hydrocarbon or its isomers; diesel fuel; gasoline; petroleum ether, kerosene or their mixtures. The presented compound organic solvent can further advantageously contain auxiliaries, an anti-corrosion agent or additives - individually or in combination with each other.

Description

The field of technology

The technical solution relates to a compound organic solvent and a method of removing impurities of petroleum origin from hard surfaces, such as the surfaces of pipelines and technological equipment or their parts.

Current state of the art

Cleaning technological equipment or their parts, as well as storage tanks for petroleum substances after a certain time requires the removal of deposits, sediments and deposits. These residues, as well as mechanical impurities, complicate the technological process, e.g. rectification or degrade stored substances. In industrial units processing oil and its products, refineries and transport facilities, deaf, hard-to-access holding spaces are often created, which do not allow them to be cleaned of oil residues during repairs. Rectification and exchanger units and their boilers, as well as the surfaces of technological equipment, represent a special problem. The simplest and most frequently used system for cleaning tanks and product lines is cleaning with diesel, or with gasoline with a high boiling point and subsequent blowing with water vapor and subsequent inerting of the system. Another problem is cleaning the surfaces of technological equipment and parts. The most common method is cleaning with diesel fuel. The diesel itself, or gasoline with a high boiling point have limited use, e.g. they do not remove accompanying polar impurities. Due to the negative effects of such use of diesel on the environment, replacements are being sought. Such substitutions can be tested according to Kulkarni, M., et al., J. Testing and Evolution, 429-437 (2003). The use of highly concentrated alkaline solutions for cleaning is also limited due to their corrosive properties.

Despite the fact that there are many methods of cleaning from oils, or of petroleum substances, this problem is still not satisfactorily solved, as toxic residues are created in all existing methods, which must be disposed of afterwards. The alternative is represented by more easily biodegradable organic solvents with a low health risk, replacing at least part of the solvent based on hydrocarbons. Such solutions are described, for example, in the following patent documents:

Patent document US2012207065 describes a mixture of non-azeotropic fluorocarbons for removing residual hydrocarbons from tanks and technological equipment of liquid hydrocarbon mixtures.

Patent files, e.g. EP2862843, RU94030825, US 7229952, describe the use of various organic polymers, often with the addition of chlorinated agents, for cleaning oil-contaminated surfaces.

Patent file US2018201878 describes a composition of amine oxides, polysiloxanes for cleaning technological equipment contaminated with oil and its deposits.

Patent document CN112322403 describes a composition of fatty acid esters, inorganic bases and high boiling point hydrocarbons (eg diesel) for cleaning oil-contaminated surfaces.

Patent document SK 280944 describes an agent for removing hydrocarbon residues and their mixtures from tanks and technological equipment of liquid hydrocarbon mixtures, the essence of which is hydrophilized carbon with a specific size.

Patent document CS 222456 describes the removal of residual hydrocarbons as impurities by an aqueous suspension of dispersed carbon.

A similar solution is presented in file CZ 278051, whereby carbon black (activated carbon) is brought into contact with oxygen at a pressure of 4 MPa and a temperature of 300 °C and subsequently hydrophilized.

Patent file EA201650128 for the removal of residual hydrocarbons, or of decomposition products as impurities describes the composition of aromatic hydrocarbons or kerosene and copolymers of glycerol and ethylene oxide or propylene oxide with mol. weighing 3,600 to 6,000, particularly suitable for removing asphalt deposits in technological equipment.

US 2014/0221709 relates to hydrocracking, using C3 to C7 alkanes, aromatic solvents, diesel or their mixture for deasphalting.

In file RU2015/000855 microgels of polysaccharides and surfactants are used to remove oils from tanks, soils and object surfaces.

Patent document SK 241-98 describes polycarbonate polymers for removing oil and fat impurities from various surfaces and textiles.

Patent file RU2755747 describes the application of diesel fuel and a special vacuum device for cleaning oil-contaminated tanks.

File US2021261889 describes a composition consisting of 60% biodiesel, 40% C1 to C5 esters of aromatic acids, terpenes, diethylene glycol butyl ether, surfactants and cosolvents used for cleaning equipment.

In addition to ecological unsuitability, the procedures used so far using halogenated solvents are also demanding on technological operations, especially on the necessity of long-term action of these solvents. In the case of other known procedures from the state of the art, mainly mixtures of aliphatic and aromatic hydrocarbons and surface-active substances are used. The disadvantage of the current procedures is primarily the high consumption of solvents compensating for their low cleaning efficiency, especially in the case of impurities accompanied by polar substances.

From the overview, it follows that there is still a need for an organic solvent for removing oil impurities from hard surfaces, which replaces a significant part of hydrocarbons and whose possible application at a higher temperature will achieve increased cleaning efficiency while allowing the use of smaller amounts of solvent. The mentioned deficiencies from the state of the art are solved by a compound organic solvent according to the presented technical solution, which, with a suitable combination of its individual components, also enables the removal of polar impurities, which until now required long-lasting processes with a high demand for the amount of solvent. The solution thus significantly improves the ecological safety of the cleaning process.

The essence of the technical solution

The essence of the presented technical solution is a compound organic solvent that contains 0.1 to 35% by weight. of an organic solvent selected from the group including:

- C2 to C4 carboxylic acid esters, where the ester group is independently selected from the group comprising C4 to C6 alkyl, branched C3 to C7 alkyl or cyclohexyl;

- linear or branched C3 to C7 ketones, acetophenone, cyclohexanone, C1 to C2 alkyl substituted cyclohexanone;

- alcohols with linear or branched C5 to C12 alkyl, cyclohexanol, C1 to C3 alkyl group substituted cyclohexanol;

- C4 to C8 alkyl ethers;

- ethylene glycol or its ethers, such as ethylene glycol dimethyl ether, ethylene glycol monomethyl ether, ethylene glycol butyl ether, diethylene glycol monomethyl ether, diethylene glycol diethyl ether;

- 1,2-propanediol or its ethers, 1,3-propanediol, triethylene glycol, hydroformylation products of 1-propene;

- or their mixtures;

whereas the rest of the total weight of the composition is a linear or branched C4 to C22 hydrocarbon or its isomers; diesel fuel; gasoline; petroleum ether; kerosene or their mixtures.

The compound organic solvent can advantageously contain auxiliaries, anti-corrosion preparations and additives as additional components - individually or in combination with each other.

Substances selected from the group including surface-active substances can be used as auxiliary substances. A surfactant suitable for use in a compound organic solvent according to the presented technical solution can be, for example, sodium dodecylbenzene sulfonate, sodium lauryl sulfate, or nonionic surfactants based on ethylene oxide or propylene oxide, or a combination thereof. Their application in the field of cleaning and degreasing is well known. Their content in the compound organic solvent ranges from 0.1 to 5% by weight, based on the weight of the compound organic solvent.

The so-called anti-corrosion agents can advantageously be used within the presented technical solution. universal dual-function preservative-lubricating oils. The anti-corrosion agent is preferably selected from the group including mineral oil, lithium lubricants, Teflon lubricants, hydrocarbon polymers, WD40 or their combinations. In the presented compound organic solvent, they represent a content of 0.5 to 3% by weight, based on the weight of the compound organic solvent.

In addition to the fact that anti-corrosion agents can be used as a component of a combined solvent, they can also be used after the removal of oil impurities from hard surfaces to treat an already cleaned surface. As an example of such an anti-corrosion agent, commercially available anti-corrosion liquids can be mentioned, for example from the company Kluber or WD40 (provided by the manufacturer as a mixture of C9-C11 hydrocarbons, n-alkanes, isoalkanes, cycloalkanes and less than 2% aromatics). Their use makes cleaning more efficient and the treated surfaces are protected against water, which increases their resistance.

Another optional component of the presented combined solvent are additives in the amount of 2 to 10% by weight, based on the weight of the compound organic solvent, selected from the group including C1 and C2 esters of fatty acids, especially of vegetable origin, such as MERO (rapeseed oil methyl ester), glycerin or combinations thereof. Oils of natural origin are commonly used as a source of the mentioned fatty acids, e.g. rapeseed oil.

For the purposes of the invention, the term compound organic solvent is used, which characterizes the presence of several components. Mixing two or more mutually miscible organic solvents creates a compound solvent. The advantage is that the compound solvents according to the presented technical solution are characterized by a high dissolving power. The combination of solvents used enables the balance of hydrophilic and lipophilic properties so that even a thin layer of the compound solvent is sufficient to dissolve pollution. It is important to significantly influence the hydrophobic character of the compound solvent, as persistent impurities from petroleum substances represent a complex system containing polar substances. This influence is manifested, among other things, in the wettability of materials. Another advantage is also the commercial availability of individual solvent components and a lot of knowledge about their physico-chemical and toxicological properties. Mixed solvents according to the technical solution are obtained in a very simple way, by mixing individual solvents and advantageous other components in the required ratio in a homogenization tank, while the mixing heat can be compensated by gradual dosing.

It is obvious to a person skilled in the art that it is possible to prepare a compound solvent in this way for a specific cleaning process. This is particularly advantageous for cleaning equipment from standardized processes, e.g. stills from distillations.

For the purposes of the presented technical solution, the term oil impurities or oil residues includes substances that are present in various applications of diesel or its products, such as oils, waxes, asphalts, pitches, residual products from distillations, which have a boiling point higher than 190 to 350 °C and include paraffins, aromatic substances, as well as heterocyclic substances containing sulfur and nitrogen, often with polar properties.

For the purposes of the presented technical solution, the term "hard surface" represents the surface, especially the inner surface of pipelines, product pipelines and technological equipment or their parts, containment areas, storage tanks, while the term also includes the surface of objects, such as individual components of technological equipment.

Compound organic solvents according to the presented technical solution combine optimal cleaning efficiency in combination with employee protection and reduction of environmental pollution. Another advantage is that they effectively remove persistent impurities from petroleum substances, lubricants, bitumen, hardened carbon residues from thermal decomposition during distillation or oil and pollution from nozzles. Due to their composition, the presented compound organic solvents are characterized by a strong affinity to petroleum substances and polar impurities, they evaporate more slowly than the individual solvents used, consequently their action time is longer and the result is a high level of effectiveness and efficiency. The advantage is that they do not leave any oily residue on cleaned surfaces. Compound organic solvents, which are the subject of the presented technical solution, are characterized by a high flash point (>100 °C), which increases work safety during their application. It turned out that the compound organic solvents according to the technical solution are particularly effective, have unique dissolving properties, are highly ecological, with a high flash point and low toxicity. They are suitable as a replacement for the currently used industrial solvents of petroleum origin, such as diesel or alkaline solvents.

The method of removing impurities of petroleum origin from hard surfaces according to the presented technical solution includes bringing the hard surface into contact with a compound organic solvent according to the technical solution. Such contacting involves application by application to the cleaned surface either by hand or by means of devices such as nozzles or a sprayer and may be in the form of a solution or hydroemulsion. In the case of equipment parts or components, these can be immersed in a solvent bath. In the case of cleaning larger technological equipment and pipe systems, the solvent is filled into the equipment or system.

Improving the quality of cleaning and increasing the speed of cleaning can be achieved by dosing mixed solvents in the process taking place in drums, either rotary or vibrating. In this case, it is also possible to use an elevated temperature in the cleaning process, which has a beneficial effect on the speed of the process.

Advantageously, the entire process of removing impurities of petroleum origin according to the presented technical solution takes place at a temperature of 15 to 220 °C. Since solvents with a high boiling point are preferred, it is possible to advantageously work at a higher temperature of 60 to 200 °C, working temperatures of 110 to 180 °C are particularly advantageous. The compound organic solvent according to the presented technical solution makes it possible to use a higher temperature and at the same time to use a smaller amount of solvent, which is particularly suitable for cleaning asphalt residues. Due to the properties of the compound solvent, this is without special requirements for storage in terms of safety. The advantage is the possibility of application in a wide concentration range of the individual components of the final product, and thus influencing e.g. the ability to remove impurities by adjusting the ratio of individual components. From the point of view of operation, cleaning chamber devices, preferably with suspended conveyors, are suitable for the purposes of the invention. The general conditions for the operation of sources and their equipment, in which organic solvents are used, are regulated by the decree of the Ministry of the Interior of the Slovak Republic, and emission limits and technical requirements are established. Processes carried out outside the facility must be carried out in such a way that emissions of volatile organic compounds are minimized. Processes must be carried out in defined areas using the so-called degreasing tables or similar devices.

In the next step, the cleaned hard surface is preferably further dried. A suitable drying method is, for example, air drying.

Another advantage according to the presented technical solution is that in the process of cleaning hard surfaces, it is possible to obtain clean surfaces in the final part, which can be further treated against corrosion in the technological process.

The effectiveness of cleaning and degreasing preparations can be evaluated by laboratory - analytical methods [Transfer of innovations 27/2013, Kreibich, Viktor. Theories and technologies of surface treatments. 1st ed. Prague: ČVUT, 1996.]. First, the sample, which is the surface of the steel sheet, is artificially contaminated with a selected lubricant (e.g. technical vaseline) and the amount of the contaminated sample is quantified gravimetrically. After cleaning with the selected means, the weight loss of the polluted sample representing the removed impurity is determined. In the event that it is necessary to determine the efficiency of the cleaning process for large technological devices, the mass concentration loss of the impurity in the rinsing waters before cleaning and after cleaning with a solvent is evaluated.

In the following examples, compound organic solvents according to the presented technical solution are described, as well as the evaluation of the efficiency of the method of removing impurities of petroleum origin from hard surfaces according to the presented technical solution. The examples serve to further clarify the presented technical solution without limiting it to the given examples.

Implementation examples

Example 1

Evaluation of the effectiveness (i.e. cleaning ability) of the compound solvent ethylene glycol monomethyl ether 6.5% - isooctane 71.0% - methylbutyl ketone 22.5%.

A steel sheet coated with technical vaseline 15.128 gm ^-2 , 14.251 gm ^-2 and 14.853 gm ^-2 was placed in a container equipped with a stirrer, and the sheet thus contaminated was weighed. Subsequently, this plate was covered with 125 ml of the compound solvent ethylene glycol monomethyl ether 6.5% - isooctane 71.0% - methylbutyl ketone 22.5% in the form of a solution and at temperatures of 30 °C, 60 °C and 80 °C the bath was stirred for 5 minutes . Then the test plate was removed from the bath, covered with 75 ml of water at 35 °C for 10 minutes, then dried in air and weighed. The effectiveness of the used solvent was evaluated gravimetrically as the difference in the determined weights of the contaminated steel sheet before and after contact with the compound solvent. The highest efficiency of 99.0% was achieved at a bath temperature of 80°C, with a rinse in water at a temperature of 35°C for 10 minutes, the lowest efficiency of 81.2% at a bath temperature of 30°C. When mixing the application solution, the system does not foam, it is suitable for cleaning technologies of machine parts. When cleaning with a brush for 10 minutes and rinsing in water at a temperature of 30 °C for 10 minutes, an efficiency of 99.5% was achieved.

Examples 2 to 13

Using an analogous procedure as in example 1, the effectiveness of various compound solvents according to the presented technical solution was evaluated, while their composition and the temperature at which the solvent worked are shown in the following table. Rinsing with water was carried out at a temperature of 35 °C. In example 4, the compound solvent is used as a hydroemulsion, in the other examples, the compound solvent is used in the form of a solution.

Table

Example no. Organic solvent 1 Organic solvent 2 Anti-corrosion agent Additive Rest Efficiency (%) Content (% by weight) Content (% by weight) Content (% by weight) Content (% by weight) Content (% by weight) Temperature (°C) 2 cyclohexanol methylpropyl ketone — — isooctane 99.1 10 15 75 80 3 cyclohexanol — — diesel fuel 99.5 15 85 150 4 butyl butyrate methyl isopropyl ketone MEASURE gasoline 98.84 1.5 25 5 68.5 120 5 cyclohexanone glycerin diesel fuel 91.15 6 6 88 180 6 ethylene glycol monobutyl ether — — MEASURE diesel fuel 99.02 24 — — 2 74 60 7 diethylene glycol methyl ether hydroformylation products of 1-propene WD40 — hexadecane 97.4 12 12 0.5 — 75.5 60 8 2-heptanone butyl ether — MEASURE petroleum ether 96.2 25 10 — 10 55 90 9 methylcyclohexanone — — — isooctane 99.1 20 — — — 80 40 10 2-heptanone 2-methyl-3-hexanol — — kerosene 98.7 10 15 — — 75 150 11 ethylene glycol butyl ether — — MEASURE diesel fuel 97.6 35 — — 5 60 120 12 hydroformylation products of 1-propene — — — diesel fuel 99.1 12 — — — 88 110 13 hydroformylation products of 1-propene — — — diesel fuel 91.1 5 — — — 95 110

Example 14

A model exchanger of an experimental distillation unit was used to determine the effectiveness of complex organic solvents for cleaning hard surfaces from petroleum impurities. The exchanger consisted of U-tubes and was composed of a tube sheet with a total length of 3.5 m, with an attached chamber with a longitudinal partition for separating substances of different temperatures. 30 l of water with a temperature of 90 °C was pumped into the system in three batches. The concentration of oil substances in the rinse water ranged from 158 mg/l - 222 mg/l.

Subsequently, the system was flushed in three doses of 21 l of a compound solvent consisting of cyclohexanol 25%, diesel 74.5% and 0.5% sodium dodecylbenzenesulfonate at a temperature of 85-90°C and the last flushing dose at a temperature of 110°C. The combined solvent was drained from the system and then the system was air dried. The subsequent rinsing of 7 l of water with a temperature of 60 °C showed 3.8 mg/l of extractable substances.

SK 9697 Υ1

Industrial applicability

The presented technical solution is used for cleaning hard surfaces, objects, materials, pipelines and technological devices or spaces. The advantage is a homogeneous process environment, replacement of 5 halogenated hydrocarbons or basic agents with economically acceptable solvents. The benefit of the application of complex organic solvents is a low health risk, replacement of part or the entire volume of hydrocarbon-based solvents, or halogenated hydrocarbons, simple implementation of the process and application of commercially available and long-term proven solvents.

Claims (8)

CLAIMS FOR PROTECTION 1. A compound organic solvent for removing oil impurities from hard surfaces, characterized in that it contains 0.1 to 35% by weight. an organic solvent selected from the group consisting of: C2 to C4 carboxylic acid esters, wherein the ester group is independently selected from the group consisting of C4 to C6 alkyl, branched C3 to C7 alkyl, or cyclohexyl; linear or branched C3 to C7 ketones, acetophenone, cyclohexanone, C1 to C2 alkyl substituted cyclohexanone; alcohols with linear or branched C5 to C12 alkyl, cyclohexanol, C1 to C3 alkyl substituted cyclohexanol; C4 to C8 alkyl ethers; ethylene glycol or its ethers, such as ethylene glycol dimethyl ether, ethylene glycol monomethyl ether, ethylene glycol butyl ether, diethylene glycol monomethyl ether, diethylene glycol diethyl ether; 1,2-propanediol or its ethers, 1,3-propanediol, triethylene glycol, hydroformylation products of 1-propene; or mixtures thereof; whereas the rest of the total weight of the composition is a linear or branched C4 to C22 hydrocarbon or its isomers; diesel fuel; gasoline; petroleum ether; kerosene or their mixtures. 2. Compound organic solvent according to claim 1, characterized in that it further contains an auxiliary substance selected from the group including surfactants, in an amount of 0.1 to 5% by weight, based on the weight of the compound organic solvent. 3. Compound organic solvent according to claims 1 or 2, characterized in that it further contains an anti-corrosion agent in an amount of 0.5 to 3% by weight, based on the weight of the compound organic solvent, selected from the group including mineral oil, lithium lubricants, Teflon lubricants , hydrocarbon polymers, WD40 or combinations thereof. 4. Compound organic solvent according to any one of the preceding claims, characterized in that it further contains additives in an amount of 2 to 10% by weight, based on the weight of the compound organic solvent, selected from the group including C1 and C2 fatty acid esters, in particular of vegetable origin, such as rapeseed oil methyl ester (MERO), glycerin or combinations thereof. 5. Compound organic solvent according to any one of the preceding claims, characterized in that it is in the form of a solution or hydroemulsion. 6. A method for removing oil impurities from hard surfaces, characterized in that the hard surface to be cleaned is brought into contact with the compound organic solvent according to any one of claims 1 to 5. 7. The method according to claim 6, characterized in that it takes place at a temperature of 15 to 220 °C, preferably at a temperature of 60 to 200 °C, more preferably at a temperature of 110 to 180 °C. 8. The method according to any one of claims 6 or 7, characterized in that the cleaned hard surface is further dried.