RU2749133C1 - Method for obtaining frost-resistant aldehyde solution (variants) - Google Patents

Abstract

FIELD: chemistry.SUBSTANCE: present invention relates to variants of a method for producing a frost-resistant aldehyde solution that can be used as a corrosion inhibitor in the oil industry as a chemical reagent that neutralizes hydrogen sulfide and mercaptans, as well as for the production of surfactants in the petrochemical and oil refining industries. One of the variants of the method includes cooling a 55% formalin solution supplied from a formalin production plant and having a temperature of 60-70°С to a temperature of 50-52°С, mixing it in a mixer with methyl alcohol and keeping the resulting solution while stirring it in a container with cooler for 3 hours at a temperature of 50-52°С. At the same time, a 55% formalin solution contains (wt %): formaldehyde 54.5–55.5, methanol 0.5–1.0, the rest is distilled water, and the following amount of components (wt %) is fed into the mixer: formalin 36.5–79.05, methanol 29.95–63.5.EFFECT: proposed variants make it possible to increase safety of the manufacturing process of the cold-resistant aldehyde solution while ensuring the required consumer properties of the solution.2 cl, 4 ex

Description

The invention relates to the chemical industry, in particular, to the production of aldehyde, frost-resistant solutions. These solutions can be used as a corrosion inhibitor in the oil industry, can be used as chemical reagents that neutralize hydrogen sulfide and mercaptans that arise during the production and transportation of hydrocarbon fluids through pipes, such as oil, gas condensate, oil-water emulsions, oil products and process fluids. Also, these solutions can be used for the production of surfactants in the petrochemical and oil refining industries. Solutions are intended for use at low temperatures, in particular, at temperatures below -70 ° C, in the Far North.

Known methods for producing an aqueous solution of formaldehyde and methyl alcohol by catalytic dehydrogenation of methanol on metal, oxide and metal oxide catalysts, followed by absorption of formaldehyde with water and / or water-carbamide solution. To obtain this solution, it is necessary to constantly change the technological process at the stage of absorption. The disadvantages of these methods are the impossibility to regulate the concentration of the finished product due to the fixed amount of air determined by the stoichiometry of the processes in the contact apparatus, the complication of the hardware design due to the need to use absorption columns.

A known neutralizer of hydrogen sulfide and a method of its use according to the RF patent for invention No. 2522459, C10G 29/20, 2014, including a nitrogen-containing organic base and / or hydroxide of an alkali metal and a formaldehyde-containing product. As the latter, it contains paraformaldehyde and a formalin-methanol mixture containing at least 20% methanol. To obtain the finished product, a formalin-methanol mixture is loaded into a thermostated flask equipped with a stirrer and a thermometer, and dimethylethanolamine and paraformaldehyde are introduced with stirring. The resulting suspension is stirred at a temperature of "+50" - "+ 60" ° C until paraformaldehyde is completely dissolved. The disadvantage is the low frost resistance of the neutralizer, the insecurity of its production.

A known neutralizer of hydrogen sulfide and a method of its use according to the patent of the Russian Federation for invention No. 2517709, C10G 29/20, 2014. The neutralizer of hydrogen sulfide includes urotropine and formalin, additionally contains a lower aliphatic alcohol, mainly methanol, with the following ratio of components, wt. % urotropin 1 - 12, methanol 14 - 38, formalin - the rest. To obtain a neutralizer, the required amount of formalin is loaded into a container equipped with a stirrer and a thermometer, with stirring, urotropin is introduced and the resulting suspension is stirred at a temperature of "+20" - "+ 40" ° C until the complete dissolution of the urotropine. Then add the calculated amount of methanol and mix until a homogeneous product is obtained. The resulting composition is used as a neutralizer without additional processing and purification. The disadvantage is the high explosiveness of the mixing process of the components, as a result of which explosive compounds can form.

As the closest analogue to both variants of the proposed technical solution, a method of obtaining effective reagents with a high absorption rate of hydrogen sulfide and mercaptans, stable at low temperatures, was chosen according to RF patent for invention No. 2665475, C10G 29/24, 2018. The method provides for the production of a neutralizer based on concentrate 41 -55% formaldehyde solution formed during the oxidation of methanol, with the addition of any base, amines or alkali, while methanol is added additionally after receiving 41-55% formaldehyde solution. The disadvantage is that in industrial volumes, with the simultaneous mixing of formalin and methanol without preliminary cooling of formalin, a reaction proceeds with the release of a large amount of heat. This leads to uncontrolled boiling of the solution and the formation of explosive compounds.

The technical result of the claimed invention is to improve the safety of the process of manufacturing a solution of aldehyde frost-resistant while ensuring the required consumer properties of the solution.

The technical result according to the first embodiment of the invention is achieved by the fact that in the method of obtaining a solution of aldehyde frost-resistant, including mixing a 55% formalin solution with methyl alcohol, according to the invention, a 55% formalin solution supplied from a formalin production plant and having a temperature of "+60 "-" +70 "ºС, to a temperature of" +50 "-" +52 "ºС, mix it in a mixer with methyl alcohol, the resulting solution is kept, stirring it, in a container with a cooler, for 3 hours at a temperature" +50 "-" +52 "ºС, while the 55% formalin solution contains (wt%):

Formaldehyde …………………………… 54.5 - 55.5

Methanol …………………………………… ..0.5 - 1.0

The rest ………………… distilled water,

the following amount of components is fed into the mixer (wt%):

Formalin ……………………………… 36.5 - 79.05

Methanol ……………………………… ..29.95 - 63.5

The technical result according to the second embodiment of the invention is achieved by the fact that in the method of obtaining a solution of aldehyde frost-resistant, including mixing a 55% formalin solution with methyl alcohol, according to the invention, a 55% formalin solution supplied from a formalin production plant and having a temperature of "+60 "-" +70 "ºС, to a temperature of" +50 "-" +52 "ºС, mix it in a mixer with methyl alcohol and demineralized water, the resulting solution is kept, stirring it, in a container with a cooler, for 3 hours at a temperature of "+50" - "+52" ºС, while a 55% formalin solution contains (wt%):

Formaldehyde ……………. ……. 54.5 - 55.5

Methanol ……………………… .. …… 0.5 - 1.0

The rest ... ... ... .... distilled water,

the following amount of components is fed into the mixer (wt%):

Formalin ………………………… .66.1-70.3

Methanol …………………………… 20.1-33.0

Demineralized water ………… .1,0-9,6

The technical result for both options is provided due to the fact that the 55% formalin solution received from the formalin production unit is cooled to a temperature of "+50" - "+52" ºС. This temperature limit for pre-cooling before mixing formalin with methyl alcohol is optimal. An increase in temperature above "+52" ºС will lead, with further mixing of the components, to a chemical reaction with the release of a large amount of heat. This, in turn, will lead to uncontrolled boiling of the solution and the formation of explosive compounds. If the temperature is below "+50" ºС, then the equipment will become paralyzed, in particular, the heat exchanger. Further mixing of a 55% formalin solution in a mixer with methyl alcohol, or with methyl alcohol and demineralized water, avoids the release of a critical amount of heat during mixing due to pre-cooling and, at the same time, supply a strictly defined amount of components to the mixer, which is necessary to ensure the required properties of the final product. In the proposed method, there is no dependence of the concentration of the finished product on the amount of air supplied to the contact apparatus, since a ready-made solution of formaldehyde and ready-made methyl alcohol - technical methanol are fed through the mixer. Due to this, solutions with the desired desired properties are obtained at the outlet. The concentration of the finished product is controlled using flow meters and valves at the mixer inlet. Thus, after mixing the components in the mixer, a cooled, frost-resistant aldehyde solution is already formed. This solution is fed into a container, in which, due to the coil with circulating water and a submersible mixer installed in it, the required temperature of the solution is maintained. This allows stabilization of the solution, which is achieved by holding at a temperature of "+50" - "+52" ºС for three hours. The holding temperature is due to the fact that at temperatures below +50 ºС, formaldehyde polymers precipitate in the form of an insoluble precipitate. The holding temperature above "+52" ºС leads to a chemical reaction with the release of a large amount of heat, uncontrolled boiling of the solution with the formation of high-boiling, explosive semiformals, such as methylal and methyl formate. The content of 54.5 - 55.5 wt.% Formaldehyde and 0.5 - 1.0 wt.% Methanol in a 55% formalin solution and feeding into the mixer the amount of formalin and methanol specified for each variant of the method allows to provide the necessary consumer properties of the finished product ... The content of methanol in the product provides its required frost resistance, the content of formaldehyde provides the required amount of absorption of hydrogen sulfide. Demineralized water according to the second embodiment of the method is added in the case of preparing a product with a low content of formaldehyde and methanol. Thus, the explosion and fire safety of the process of manufacturing an aldehyde frost-resistant solution in the proposed method increases while ensuring the required consumer properties of the finished product.

The method of obtaining a solution of aldehyde frost-resistant is as follows.

From any installation for the production of formalin, formalin is fed with a concentration of 55 wt.% At a temperature of "+60" - "+70" ° C through a mass flow meter and a control valve into a heat exchanger. In a heat exchanger, 55% formalin is cooled with water to a temperature not lower than +50 ° С. Further, cooled formalin with a temperature not lower than "+50" ° C is directed through a pipeline to the mixer. Also, technical methanol with a methanol content of at least 99.95 wt.% Is fed to the mixer. In this case, the amount of components required for their concentration in a specific finished product is controlled using mass flow meters and valves at the mixer inlet. All control of flow meters and valves is carried out through the controller (APCS) in automatic mode. The required amount of loaded formalin and methanol is determined depending on the required percentage of these components in the final ready-made solution of aldehyde frost-resistant. In addition, the amount of formalin loaded is influenced by the formaldehyde and methanol content in formalin. After mixing the components, a cooled, frost-resistant aldehyde solution is obtained. The prepared solution is fed through the pipeline into a container equipped with an internal stainless steel coil, in which circulating water circulates to maintain the required solution temperature, and is kept at a temperature not lower than +50 - +52 ºС for 3 hours to stabilize. In addition, the tank is equipped with a submersible stirrer for uniform mixing of the solution throughout the entire volume of the tank.

If it is necessary to obtain a product with a low content of formaldehyde and methanol, the proposed method is carried out according to the second embodiment, in which demineralized water is added. The second variant of the method contains similar operations described above. In addition to cooled 55% formalin and methanol, demineralized water is fed to the mixer through a mass flow meter and a control valve.

Removal of the heat released during the chemical reaction of the interaction of formaldehyde and methyl alcohol prevents the mixture from heating up to explosive and fire-hazardous temperatures, which, accordingly, leads to safe work.

Examples of implementation of the method.

Example 1.

Concentrated formalin with a formaldehyde content of 54.81 wt.%, With a methanol content of 0.93 wt.% In an amount of 124 kg at a temperature of "+60" ºC is loaded into the heat exchanger, the formalin concentrated to a temperature of "+52" ºC is cooled, served in a mixer , served in the mixer technical methanol with a methanol content of 99.95 wt.% in the amount of 53 kg, at the outlet of the mixer receive an aldehyde frost-resistant solution in the amount of 177 kg with a formaldehyde content of 38.40 wt.%, with a methanol content of 30.58 wt. %, the resulting solution is sent to a container in which it is kept at a temperature of "+50" - "+52" ºС for 3 hours with constant stirring. A stabilized aldehyde frost-resistant solution with a freezing point below -72 ºС is obtained.

Example 2.

Concentrated formalin with a formaldehyde content of 55.10 wt.%, With a methanol content of 0.60 wt.% In an amount of 100 kg at a temperature of "+68" ºC is loaded into the heat exchanger, the formalin concentrated to a temperature of "+50" ºC is cooled, served in a mixer , then technical methanol with a methanol content of 99.95 wt% in an amount of 160.08 kg is fed into the mixer, an aldehyde frost-resistant solution in an amount of 260.08 kg is obtained at the outlet of the mixer with a formaldehyde content of 20.40 wt%, with a methanol content 59.46 wt.%, Send the resulting solution into a container in which it is kept at a temperature of "+50" - "+52" ºС for 3 hours with constant stirring. A stabilized aldehyde frost-resistant solution with a freezing point below -72 ºС is obtained.

Example 3.

Concentrated formalin with a formaldehyde content of 55.10 wt.%, With a methanol content of 0.60 wt.% In an amount of 92 kg at a temperature of "+70" ºС is loaded into the heat exchanger, the formalin concentrated to a temperature of "+50" ºС is cooled, served in a mixer , then technical methanol with a methanol content of 99.95 wt.% in an amount of 160.08 kg is fed into the mixer, an aldehyde frost-resistant solution in an amount of 252.08 kg is obtained at the outlet of the mixer with a formaldehyde content of 20.11 wt.%, with a methanol content 63.69 wt.%, The resulting solution is sent to a container in which it is kept at a temperature of "+50" - "+52" ºС for 3 hours with constant stirring. Get a stabilized aldehyde frost-resistant solution with a freezing point below "-72" Cº.

Example 4.

Concentrated formalin with a formaldehyde content of 55.20 wt.% With a methanol content of 0.90 wt.% In an amount of 350 kg is loaded into the heat exchanger at a temperature of "+65" ºC, the formalin concentrated to a temperature of "+51" ºC is cooled, served in a mixer, then technical methanol with a methanol content of 99.95 wt.% in an amount of 100.05 kg and demineralized water in an amount of 48 kg are fed into the mixer, at the outlet of the mixer an aldehyde frost-resistant solution is obtained in an amount of 498.05 kg with a formaldehyde content of 38.79 wt. .%, with a methanol content of 20.71 wt.%, the resulting solution is sent to a container in which it is kept at a temperature of "+50" - "+52" ºС for 3 hours with constant stirring.

Thus, the claimed invention makes it possible to increase the explosion and fire safety of the process of making a frost-resistant aldehyde solution while ensuring the required consumer properties of the solution, such as frost resistance and the ability to neutralize hydrogen sulfide.

Claims (8)

1. A method of obtaining a solution of an aldehyde frost-resistant, including mixing a 55% formalin solution with methyl alcohol, characterized in that a 55% formalin solution supplied from a formalin production plant and having a temperature of 60-70 ° C is cooled to a temperature of 50-52 ° C, mix it in a mixer with methyl alcohol, the resulting solution is kept, stirring it in a container with a cooler for 3 hours at a temperature of 50-52 ° C, while a 55% formalin solution contains (wt%): Formaldehyde 54.5–55.5 Methanol 0.5-1.0 Rest distilled water, the following amount of components (wt%) is fed to the mixer: Formalin 36.5-79.05 Methanol 29.95-63.5 2. A method of obtaining a solution of an aldehyde frost-resistant, including mixing a 55% formalin solution with methyl alcohol, characterized in that a 55% formalin solution supplied from a formalin production plant and having a temperature of 60-70 ° C is cooled to a temperature of 50-52 ° C, mix it in a mixer with methyl alcohol and demineralized water, the resulting solution is kept, stirring it in a container with a cooler for 3 hours at a temperature of 50-52 ° C, while a 55% formalin solution contains (wt%): Formaldehyde 54.5–55.5 Methanol 0.5-1.0 Rest distilled water, the following amount of components (wt%) is fed to the mixer: Formalin 66.1-70.3 Methanol 20.1-33.0 Demineralized water 1.0-9.6