Process for producing formalin or urea-formaldehyde solution

FIELD: industrial organic synthesis.

SUBSTANCE: process comprises providing alcohol-water-gas mixture via evaporation of water-methanol mixture, combining the latter with air and emission gas, catalytic dehydrogenation of methanol on silver catalyst at elevated temperature followed either absorption of formaldehyde from reaction gases or chemisorption thereof from indicated gases with urea solution in column to produce and recover formalin in case of absorption or urea-formaldehyde solution in case of chemisorption. Into absorption/chemisorption stage, preheated emission gas is supplied in weight proportion to methanol (0.25-6,8):1. Generally, emission gas is preheated to 50-130°C.

EFFECT: increased concentration of produced formalin or urea-formaldehyde solution, widened concentration control range, simplified equipment, and reduced fire risk.

2 cl, 1 dwg, 4 ex

 

The invention relates to the technology of production of formaldehyde and urea-formaldehyde solution and can be used in the manufacture of urea-formaldehyde resins and the synthesis process on the basis of formalin.

A known method of producing formaldehyde by feeding a mixture of air-methanol-water-formaldehyde in the reactor containing the catalyst, the synthesis of formaldehyde at an elevated temperature followed by a two - or three-stage absorption, while the gas-vapor mixture one absorption column is transferred to another absorption column, etc. and the final abgas leaves the last of the absorption column. The allocation of an aqueous solution of formaldehyde is carried out on a bottom part of the first column (US 4454354, 12.06.1984, IPC C 07 C 45/29).

In the described manner through the use of multiple absorption column is complicated instrumentation process and significantly reduced economic indicators

A known method of producing formaldehyde by evaporation of water-methanol mixture in the evaporator, by mixing it with air, saturated vapors of formaldehyde and water supply obtained spirtovodochnoj mixture enriched with formaldehyde in the reactor for the synthesis of formaldehyde in a silver-containing catalyst at elevated temperature and subsequent absorption of formaldehyde from the reaction g is the call of the two absorption columns and submission received after absorption formaldehydefree solution of the two absorbers in the wash column, which also serves the air (DE 2444586 C3, 10.07.1986, IPC C 07 C 47/055). The concentration of the final product (formalin) is due to the additional Stripping from it the excess water air, which is then channelled into contact apparatus for the oxidation of methanol in the presence of a silver catalyst. Water vapor contained in the air in the saturation state after Stripping of the final product, partially or completely replaces the water supplied to the dilution of methanol.

Blow-off of water vapor from formalin is performed in a separate apparatus, in order to avoid mixing of air contact with the gases. Thus, in this way the additional blow-off water from the finished product using supplied to the process air.

The disadvantages of this method are the need for Stripping in a separate device, as well as the risk of formation of explosive mixtures, as in the composition of the air in the zone of vapors of flammable liquids is injected oxidizer is oxygen.

At the same time, a fixed amount of air determined by the stoichiometry of the processes in the contact apparatus, eliminates the possibility of regulating the concentration of the finished product (formalin).

A method of obtaining urea-formaldehyde solutions by distillation of an aqueous solution of formaldehyde (contains methanol). Obtained which after distillation, the steam is directed to the stage of absorption of urea, top product absorption assign, and the bottom product is mixed with a concentrated solution of formaldehyde from the stage distillation to obtain a stable concentrated solution of urea-formaldehyde products. Also there is indication that the qualitative composition of urea-formaldehyde solution formed in the absorption apparatus, can be controlled by feeding different amounts of absorption solution and/or vapor condensate return after the stage of absorption (EN 2102403, 05.12.1994, IPC C 08 G 12/12). However, in this method the concentration of the product is due to the use of energy-consuming stage of distillation. This method involves the formation of a large number of chemically dirty runoff due to the use as raw material concentrated, water formalin with high methanol content.

Also known a method of obtaining a urea-formaldehyde solution by evaporation photometering solution, mixing it with air or mixture of air with an inert gas saturated vapors of formaldehyde and water supply obtained sportowego-gas mixture enriched with formaldehyde in the reactor for the synthesis of formaldehyde in a silver-containing catalyst at elevated temperature, with submission received formaldehydefree the reaction gases on the hemosorption urea in two columns and Stripping obtained after absorption formatinstead solution of the two absorbers in the wash column of air or mixture of air and inert gas (GB 1517366, 12.07.1978, IPC C 08 G 12/12). Use a separate wash columns, processes it, and inherent in the way the disadvantages are similar to the above patent DE 2444586 C3.

The objective of the invention is to increase the fire / explosion safety of the process of obtaining formalin or formaldehyde solutions of high concentration, the extension of the range of regulation of the concentration of the finished product, as well as the simplification of the apparatus registration process.

This object is achieved by a method of producing formaldehyde or urea-formaldehyde solution, including preparation spirtovodochnogo mixture by evaporation photometering mixture, mixing with air and abhasa, catalytic dehydrogenation of methanol on silver catalyst at elevated temperature and subsequent absorption of formaldehyde from the reaction gases or by chemisorption urea solution in the column with receipt and allocation of formalin in the case of absorption or urea-formaldehyde solution in the case of chemisorption, while on stage absorption or chemisorption serves preheated abgas in a weight ratio of the methanol (0.25 to 6,8):1. Abgas when it is heated to a temperature of 50÷130°C.

In the production of formaldehyde and urea-formaldehyde concentrate exhaust gas polotical the th column (abhas) is served on the circulation in the process.

Upon receipt of formaldehyde, methanol and water are available spastically received stream photometering vapor is mixed with air and recirculating flow abhasa in ratios determined kinetic and thermodynamic conditions of the process of catalytic dehydrogenation in the contact device which is supplied with the received spirtovodochnaya mixture.

The kinetic conditions of catalytic processes is defined by the ratio of oxygen and methanol, and thermodynamic balance is determined and controlled by the amount of dosed into the process water and the circulation abhasa.

After certainareas spirtovodochnogo mixture is sent to the contact device for the catalytic dehydrogenation of methanol on silver catalyst at elevated temperature. Then received in the contact apparatus of the reaction gases, together with the additional flow abhasa is introduced into an absorption column, where the bottom is the binding of formaldehyde by absorption of water.

In the upper stage of the column, the gas is cooled to the condensation from it condensable components of water vapor, methanol and formaldehyde.

The order of execution of technological methods in a method of producing urea-formaldehyde solution is similar to the procedure of execution of methods in the method of producing formalin until p is giving the reaction gases in the column. Upon receipt of urea-formaldehyde solution in the column serves the reaction gases, an additional stream of abhasa and the urea solution in the bottom of the column there is a process of chemisorption of formaldehyde in an aqueous solution of urea, and in the upper levels, the gas is cooled to the condensation from it condensable components of water vapor, methanol and formaldehyde.

Abgas consisting of non-condensable components (nitrogen, hydrogen, carbon dioxide and others), cooled to a temperature of 10÷35°and having a low moisture content, corresponding to its temperature, is withdrawn from the upper part of the column and as in the case of absorption, and in the case of chemisorption partially sent for recycling, and partially returned to the circulation in the process.

Abgas directed to the zone of absorption (chemisorption) of the column for Stripping required amount of water from the product, is in a weight ratio of the methanol (0.25 to 6,8):1, while in the process of organizing a separate, independent circuit abhasa from the upper part to the lower part of the column. Abhas has a different moisture content at different temperatures. The higher the temperature of abhasa, the more water vapor it can make under the terms of saturation. Thus, due to the difference in the moisture content of the cold abhasa at the outlet of the column and heated abhasa in areas of the x absorption or chemisorption occurs Stripping of excess water from the product and its concentration.

The regulation of the concentration obtained in the column products (formaldehyde or urea-formaldehyde solution) by changing the number of abhasa supplied directly in the absorption/chemisorptive part of the column.

Before introduction into the column abgas heated to a temperature of bottom part of column (70÷130° (C), and the possibility of saturation of abhasa water vapor rises sharply.

In the column abgas saturated with water vapor and methanol at a temperature of absorption/chemisorption steps of adsorption columns and submits them to the upper part of the column, where the cooling abhasa water vapor and methanol are condensed and removed in the form of process condensate, which can be returned to the process for initial dilution of methanol and a solution of urea. In case of formation of excessive amounts of process condensate he may receive for recycling.

Removal from process water vapor using abhasa allows you to adjust the concentration of products - formaldehyde or urea-formaldehyde solution in a wide range by changing the number of abhasa supplied to the column. The essence of the method is illustrated in the schematic drawing and examples.

Example 1. In certainately 1 filed 2414 kg/hour of methanol, 1035 kg/h of water in the composition 70% photometering mixture and abgas number 311 nm 3/hour. For the oxidation of methanol in the process also did the air 2857 nm3/hour. Submitted abgas contained in its composition a certain amount of formaldehyde.

In spartaaaaaa 1 of the original mixture was subjected to boiling, and after mixing the vapor with air and abhasa received steam and gas flow was directed to the contact device 2 with a silver catalyst for the catalytic dehydrogenation of methanol at a temperature of 700°C. In the lower part of the absorption column 3 filed reaction gases and heated in the heat exchanger to a temperature of 50°With abhas in the number of 605 nm3/hour. The mass ratio of the circulation abhasa supplied to the process methanol is 0.25:1. In the absorption column 3 by contact cooling gases is the condensation of formaldehyde and its absorption of condensation water. The temperature of the gases at the outlet of the column was 25°C.

In the mass transfer and heat exchange processes in the column is formed an aqueous solution of formaldehyde (formalin) in the number 3772 kg/h and the concentration of formaldehyde 42,5%.

This product is a formalin increased (compared to the standard 37%formalin) concentration.

Example 2. Consumption and technological parameters of the process of obtaining the initial mixture, the catalytic degidio the tion and absorption are the same, as in example 1. To obtain the column of concentrated formalin addition to the reaction gases filed 16320 nm3/h circulation abgas heated to a temperature of 100°C. the Mass ratio of the circulation abhasa supplied to the process methanol to 6.8:1. The temperature of the gases at the outlet of the column was 25°C.

In the mass transfer and heat exchange processes in the column is formed an aqueous solution of formaldehyde (formalin) in the amount of 3380 kg/h and the concentration of formaldehyde 50%.

This product is a concentrated formalin, allowing, for example, to derive formaldehyde resin bezuparochiym method, without the formation of tar-water.

Example 3. In certainately filed 2414 kg/hour of methanol, 1035 kg/h of water in the composition 70% photometering mixture and abhas in the number of 311 nm3/hour. For the oxidation of methanol in the process did the air 2857 nm3/hour. Submitted abgas contained in its composition a certain amount of formaldehyde.

In spartaaaaaa the initial mixture was subjected to boiling, and the resulting gas-vapor stream is directed into the contact device with a silver catalyst for the catalytic dehydrogenation of methanol at a temperature of 700°C. In the lower part of the absorption column was applied for the reaction gases and abhas in the number of 605 nm 3/h with a temperature of 100°C. the Mass ratio of the circulation abhasa supplied to the process methanol is 0.25:1. In the column was also introduced 1350 kg/h of a 50% aqueous urea solution. The temperature at the exit of gases from the zone chemisorption 65° (the maximum allowable under the terms of thermodynamics of the process).

As a result of chemical reactions and heat exchange processes in the column is formed of urea-formaldehyde solution with a molar ratio of formaldehyde:urea 5:1 in the number 3869 kg/h and the concentration of the basic substance (formaldehyde + urea) 61%.

This product meets the lower boundary of the requirements for the production of urea-formaldehyde resins for wasteless technology bezuparochiym way.

Example 4. Consumption and technological parameters of the process of obtaining the original mixture, catalytic dehydrogenation and chemisorption are the same as in example 3. To obtain the column of formaldehyde solution with the maximum concentration of the basic substance (formaldehyde + urea) 85% in addition to the reaction gases filed 16320 nm3/h circulation abgas heated in the heat exchanger to a temperature of 130°C. the Mass ratio of the circulation abhasa supplied to the process methanol to 6.8:1. The temperature at the outlet of zone chemisorption - 50°With (minimum poslove chemisorption).

As a result of chemical reactions and heat exchange processes in the column is formed of urea-formaldehyde solution with a molar ratio of formaldehyde : urea 5:1 in the number 2776 kg/h when the concentration of the basic substance (formaldehyde + urea) 85%.

Thus, changing the number of circulating on the convoy of abhasa, you can control the concentration of the obtained product, regardless of the kinetic and thermodynamic conditions in the contact device. In addition, the process is executed in the same column, which simplifies instrumentation of the way when removing the possibility of the formation of explosive mixtures in the absorption column, as abhas is in relation to the products in the column with an inert gas. In addition abhasa in the production of these products can be used and another inert gas, is not having a negative effect on the kinetics of the reactions in the catalytic dehydrogenation of methanol and with sufficient capacity to compensate for the heat effect of reactions in the contact device.

1. The method of producing formaldehyde or urea-formaldehyde solution, including preparation spirtovodochnogo mixture by evaporation photometering mixture, mixing it with air and abhasa, catalytic dehydrogenation of methanol on silver catalyst at elevated pace is the atur with subsequent absorption of formaldehyde from the reaction gases or chemisorption him from these gases urea solution in the column with receipt and allocation of formalin in the case of absorption or urea-formaldehyde solution in the case of chemisorption, while on stage absorption or chemisorption serves preheated abgas in a weight ratio of the methanol (0.25 to 6,8):1.

2. The method according to claim 1, characterized in that the heating of abhasa carried out to a temperature of 50÷130°C.



 

Same patents:

FIELD: chemical technology.

SUBSTANCE: invention relates to producing urea-formaldehyde resins. Invention describes a method for preparing urea-formaldehyde resins involving condensation of urea-formaldehyde concentrate with carbamide. Condensation is carried out at the initial mole ratio formaldehyde to carbamide = (1.72-2.3):1 at temperature 80-95°C and medium pH 6-9 followed by change of pH medium to 3.5-5.5 with adduct based on a mixture of aliphatic aminoalcohols with inorganic and/or organic acids or their anhydrides no containing chloride ions or a mixture of aliphatic and heterocyclic aminoalcohols with inorganic and/or organic acids or their anhydrides no containing chloride ions, at their mass ratio = (1.0-3.0):1.0 in the amount 0.1-3.0% of urea-formaldehyde concentrate mass followed by carrying out the condensation reaction with additional amount of carbamide to achievement of viscosity value 30-80 s and the following condensation of additional amount of carbamide wherein the final mole ratio of formaldehyde to carbamide = (0.9-1.76):1 and cooling the resin. Invention provides the development of operated technology for synthesis of urea-formaldehyde resins with required properties and, first of all, the low content of formaldehyde after their hardening. Invention can be used in manufacturing urea-formaldehyde resins used as binding agents for making splint-slab and wood-fiber slabs, veneer, adhesives for gluing wood, binding agent components used in making heat-insulating materials and others.

EFFECT: improved method of synthesis of resins.

3 tbl, 1 dwg, 12 ex

FIELD: chemical industry; construction materials industry; methods of production of the carbamide-formaldehyde resin.

SUBSTANCE: the invention is pertaining to the methods of production of the water soluble carbamide-formaldehyde resins applied as binding agents and adhesives used for the timber bonding in production of the wood chipboards, the wood-fiber boards, other similar materials and the heat-insulating materials. The method of production of carbamide-formaldehyde resin provides for condensation of the amino-formaldehyde concentrate representing the aqueous composition, containing of 41.5-60.0 mass % of the formaldehyde and of 20.5-25.0 mass % of the carbamide with the viscosity controller , I the capacity of which use 37 % formalin introduced in one step together with the carbamide-formaldehyde concentrate at the stage of the alkaline condensation before the loading of the first batch of the carbamide and also at presence of 0.02-0.20 mass % of the first batch of the of the additive agent in terms of 100 mass % of the carbamide-formaldehyde concentrate and the first batch of carbamide at the heating in the water solution with the variable acidity and the following additional condensation of the formed product with the additional amount of carbamide and introduction of the second batch of the buffer additive component at the initial and the final molar ratio of carbamide and formaldehyde as 1:(1.9-2.1) and 1:(1.02-1.7) accordingly and the refrigerations of the ready resin. The technical result of the invention is optimization of the conditions for production of the low-molar carbamide-formaldehyde resins with the heightened conditional viscosity and preservation at the high level of the other quality factors.

EFFECT: the invention ensures optimization of the conditions for production of the low-molar carbamide-formaldehyde resins with the heightened conditional viscosity and preservation at the high level of the other quality factors.

2 ex, 1 tbl

FIELD: polymer production.

SUBSTANCE: invention, in particular, relates to binders used for manufacturing molding blends employed for molding profiled items from light alloys. Preparation of urea-formaldehyde binder comprises urea/formaldehyde condensation to achieve refractory index 1.4055-1.4072. Condensation is carried out at initial urea-to-formaldehyde molar ratio 1:(1.95-2.18), pH of mixture from 8 to (4.7-4.1) until viscosity of resin (using viscosimeter VS-4, nozzle 4 mm) 15.5-26.0 s, after which mixture is neutralized to pH 7.0-8.5, water is distilled off from boiling reaction mixture until refractory index achieves 1.4220-1.4230 followed by addition of polyvinyl alcohol solution at a rate of 1.2% solid substance based on initial weight of urea. Reaction mixture is then cooled and two further portions of urea are added to achieve final urea-to-formaldehyde molar ratio 1:(1.40-1.43). When second portion of urea is being charged, sodium decahydrotetraborate is simultaneously added in amount 0.35-0.7% based on the total weight of urea and then first and second post-condensation steps are conducted, each step being followed by ageing for 30-50 min.

EFFECT: reduced toxicity of resin, achieved controlled viscosity and gelation time, improved water resistance, and prolonged shelf time.

3 cl, 1 tbl, 4 ex

FIELD: polymer production.

SUBSTANCE: preparation of urea-formaldehyde resin comprises urea/formaldehyde condensation carried out in presence of ammonia at pH varying from 7.1-7.15 to 5.1-5.3 at 88-104°C, atmosphere pressure, and urea/formaldehyde/ammonia molar ratio 1:(2.0-2.2):(0.1-0.13) until viscosity (using viscosimeter VS-4) achieves 15.5-26.0 s, after which mixture is subjected to post-condensation at 77-58°C with additional urea to achieve final urea-to-formaldehyde molar ratio 1:(1.9-2.0). Reaction mixture is the given additional amount of ammonia and held at 62-38°C for 20-30 min until final urea-to-ammonia ratio 1:(0.11-0.19).

EFFECT: enabled production of low-toxicity, freely flowing binder capable of being hardened at ambient temperature for required hardening time and providing high strength to reinforced ground, reduced production expenses, and simplified equipment.

3 cl, 1 tbl, 4 ex

FIELD: polymer production.

SUBSTANCE: invention relates to production of urea-formaldehyde resins used as binders in manufacture of wood particle boards, wooden fiberboards, plywood, wood adhesives, and in other industrial fields. Invention provides a method for producing uron-containing urea-formaldehyde resins via consecutive condensation of urea-formaldehyde concentrate with solid urea first at formaldehyde-to-urea molar ratio (5.2-3.3):1, pH below or equal to 3, and temperature above or equal to 80°C and then at molar ratio (2.5-2.65):1 at pH 7.0-9.0 and 20-70°C, urea being added first in amount providing formaldehyde-to-urea molar ratio in resin (2.10-2.40):1 and then in amount providing above ratio equal to (1.50-2.09):1.

EFFECT: simplified resin production technology at the same high physicochemical properties of products based thereon and reduced toxicity of products.

3 tbl, 4 ex

FIELD: polymer production.

SUBSTANCE: production of urea-formaldehyde filler, useful as synthetic white filler in manufacture of polymers, paper, and varnish-and-paint materials, is accomplished by interaction of urea with urea-formaldehyde concentrate modified in synthesis stage with 1 to 20% of uranium derivatives and containing 54.5-59.5% formaldehyde, 21.0-24.5% urea, the rest water. Synthesis is carried out in aqueous medium in presence of phosphoric acid at elevated temperature, after which reaction mixture is neutralized with chalk/aminoalcohol/aqueous ammonia mixture [(1-4):(1-4):(1-5)]. Aminoalcohol is a product composed of 30-70% monoethanolamine, 10-50% mixture of 1-(2-hydroxyethyl)imidazol-2-ine and 1-(2-hydroxyethyl)ethylenediamine, and water (no more than 20%).

EFFECT: enhanced process efficiency and lowered oil absorption.

1 tbl, 2 ex

FIELD: polymer production.

SUBSTANCE: invention relates to technology of production of urea-formaldehyde resins with reduced toxicity used for manufacturing wood chipboards, plywood, carpenter's building ware, gluing furniture parts, for glues, varnishes, and paints. Process is accomplished by condensation of urea with urea-formaldehyde concentrate on heating in aqueous media in several steps with variable medium acidity. Starting and final urea-to-formaldehyde molar ratios are 1:(1.95-2.0) and 1:(1.05-1.2), respectively. Condensation is carried out in presence of catalyst: mother liquor of urotropin containing at least 45 wt % hexamethylenetetramine and 0.5-14 wt % formate ion and, optionally, in presence of modifier: molasses or industrial-grade lignosulfonates. Process conditions: 90-100°C and reaction time 30-60 min at pH varying from 9.0-7.0 to 5.8-5.0. After-condensation is conducted by adding urea for 30-90 min at 65-90°C followed by stabilizing product with sodium tetraborate, adjusting pH to 7.5-8.5, and cooling product to 20-30°C.According to second embodiment, process is accomplished by condensation carried out first in alkali medium (pH 8,5-6.0) for 20-40 min followed by cooling mixture to 80-85°C, and performing acid condensation at pH 5.3-5.8 in presence of acid catalyst (ammonium chloride, sulfuric acid, formic acid, acetic acid). According to third embodiment, process is accomplished by condensation in presence of at least one modifier chosen from triethanolamine, polyvinyl alcohol, and caprolactam added in two portions at starting and final urea-to-formaldehyde molar ratio 1:2.2 and 1:(1.14-1.4), respectively. In this case, condensation is conducted first in alkali medium (pH 7.3-6.0) at 85-95°C and then in acid medium (pH 4.0-5.0) in presence of acid catalyst (sulfuric acid, acetic acid). Second portion of urea is added at 55-60°C. Resulting urea-formaldehyde resins are nontoxic, have low contents of methanol (0.03-0.07%) and free formaldehyde (0.045-0.12%), high solid residue, and easily mix with water.

EFFECT: optimized process parameters and improved consumer's properties of resins.

12 cl, 3 tbl, 12 ex

FIELD: polymer production.

SUBSTANCE: in a continuous process, formaldehyde is chemically sorbed between by 45-65% aqueous urea solution in neutral or alkaline medium (pH 6.5-9.0) created by contact gases from the process of catalytic dehydrogenation of methanol to form urea-formaldehyde preconcentrate and aqueous condensate. Before chemisorption stage, contact gases are preliminarily routed to absorption stage, wherein part of formaldehyde is isolated in the form of concentrates formalin. The latter is mixed with preconcentrate obtained in the chemisorption stage at formaldehyde-to-urea molar ratio (4.5-5.2):1. Aqueous condensate is divided into process streams, one of them being used for preparation of urea solution and the other for diluting initial methanol supplied into catalytic dehydrogenation stage, whereas the rest of aqueous condensate is mixed with part of concentrated formalin to form process formalin.

EFFECT: increased stability of concentrate on storage during at least 6 months (lack of reaction product precipitates) and achieved chemical stability of formaldehyde concentrate.

2 ex

The invention relates to a method for producing urea-formaldehyde concentrate for the production of synthetic binder resins

The invention relates to the production of water-soluble urea-formaldehyde resin (UFR), used as binders and adhesives for bonding wood, manufacturing particleboard and insulation materials

The invention relates to the technology of organic synthesis, and in particular to an improved process for the preparation of formalin used in chemical industry, medicine and agriculture

The invention relates to a continuous method of obtaining aqueous solutions of formaldehyde, in particular solutions having a concentration in the range from 53 to 57 wt.%, the method includes the following stages:

(a) the air supply and methanol in the evaporator, in which the methanol is evaporated, the formation of gas-phase mixture of methanol and air;

(b) interaction of gas-phase mixture of methanol and air over the catalyst at elevated temperature to obtain a reaction mixture containing formaldehyde formed by partial conversion of methanol and water vapors and noncondensable gases;

(c) passing the reaction mixture through at least one adsorption column where the above-mentioned mixture is absorbed in the aqueous solution flowing in the opposite direction;

(d) separation of the aqueous and non-condensable gases in the absorption columns;

(e) cooling and washing of non-condensable gases that carry small amounts of methanol and formaldehyde; and

(f) the fractional distillation of an aqueous solution with the appropriate Department of methanol

FIELD: organic chemistry, in particular formaldehyde production.

SUBSTANCE: claimed method includes oxidation of hydrocarbon-containing gas with oxygen-containing gas at elevated temperature and pressure followed by reaction mixture cooling and separation of target liquid product. As hydrocarbon-containing gas ethane-containing gas is used, including natural and associated gases containing not less than 10 % of ethane. Ethane-containing gas preliminary pressed up to 2-5 MPa and heated up to 280-450°C, and oxygen-containing gas, preliminary pressed up to pressure of ethane-containing gas or more are separately fed into blenders of arranged in tandem reaction zones up to oxygen content of 2-10 vol.%. Reaction mixture is continuously cooled through wall either directly in oxidation process or before feeding thereof in next reaction zone to temperature not more than 450°C. As oxygen-containing gas air, oxygen or oxygen-enriched air are used.

EFFECT: increased formaldehyde yield, simplified process, decreased energy consumption.

2 cl, 4 ex, 1 tbl, 1 dwg

FIELD: industrial organic synthesis and chemical engineering .

SUBSTANCE: invention relates to a process of producing liquid oxygenates, including methanol, C2-C4-alcohols, formaldehyde, lower organic acids, or mixtures thereof, and to installation for implementation the process. Process comprises successively supplying natural gas from complex gas preparation plant to a series of "gas-gas" heat exchangers and into annular space of at least one tubular reaction zone of reactor, wherein natural gas is heated to temperature of the beginning of reaction, whereupon heated gas is passed to the entry of the tubular reaction zone mixer, into which compressed air or oxygen is also injected to provide gas-phase oxidation in reaction zone of reactor. Resulting reaction mixture is discharged from reactor into a series of "gas-liquid" and "gas-gas" heat exchangers, wherein reaction mixture is cooled to ambient temperature and sent to separator, wherefrom liquid phase is passed through lower carboxylic acid recovery vessel to the system of rectification columns to isolate the rest of mixture components, whereas leaving gas is recycled to complex gas preparation plant. More specifically, oxidation is carried out within temperature range 240 to 450°C and pressure from 2 to 10 MPa at residence time of reaction mixture in reactor 2-6 sec and oxidant concentration 2 to 15 wt %. In reactor having mixers hollow and at least one tubular reaction zones, required temperature is maintained constant throughout all length of tubular reaction zone and at entries for compressed air or oxygen in mixers of each of tubular reaction zones and hollow reaction zone. Liquid oxygenate production plant is composed of aforesaid complex gas preparation plant, a series of "gas-gas" heat exchanger to heat natural gas, reactor, a series of "gas-liquid" and "gas-gas" heat exchangers to cool reaction mixture obtained in reactor, gas-liquid separator, lower carboxylic acid recovery vessel, and system of rectification columns to isolate the rest of products.

EFFECT: enabled implementation of the process directly near gas and gas condensate deposits, increased conversion of methane per one passage through reactor, and increased yield of oxygenates due to improved design of plant.

6 cl, 1 dwg, 1 tbl

FIELD: industrial organic synthesis.

SUBSTANCE: formaldehyde is produced via oxidative dehydrogenation of methanol with air oxygen at high temperature on silver-containing in fixed-bed reactor enclosing gas stream distributor followed by absorption of resultant reaction gases to form methanolic formalin, which is further rectified. Gas stream distributor utilized is inert filling composed of geometrically shaped members 3-10 mm in diameter placed on grid mounted upstream of catalyst in the form of a bed 50 to 500 mm thick.

EFFECT: increased conversion and selectivity of process.

1 dwg, 4 ex

The invention relates to the chemical industry, in particular to methods of regeneration of silver catalysts for the preparation of formaldehyde from methanol

The invention relates to the technology of organic synthesis, and in particular to an improved process for the preparation of formalin used in chemical industry, medicine and agriculture

The invention relates to an improved method of dewatering solution of formaldehyde containing formaldehyde, water and methanol, including the distillation of the specified solution of formaldehyde in the presence of exciting water connection with obtaining the formaldehyde-containing product that contains significantly less water than the original solution, and use a solution of formaldehyde containing methanol at a molar ratio of methanol to formaldehyde 0.3 to 1.5:1, obtaining the formaldehyde-containing product in the form of a complex with methanol

The invention relates to an improved method for the removal of formaldehyde or its adducts of organic liquid mixtures obtained in the production of methyl methacrylate containing at least a carboxylic acid or an ester of carboxylic acid and formaldehyde or its adducts, which forms a two-phase mixture of water, comprising at least one extraction liquid organic mixture in the system liquid-liquid using water as the extractant with getting the flow of the organic phase and flow of the aqueous phase, and the flow of the organic phase contains significantly reduced the concentration of formaldehyde or its adducts compared with the liquid organic mixture
Up!