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Device and method for producing concentrated formaldehyde

A technology of concentrated formaldehyde and formaldehyde, applied in chemical instruments and methods, preparation of organic compounds, separation/purification of carbonyl compounds, etc., can solve problems such as incomplete conversion, reduction of formaldehyde, and easy oxidation of formaldehyde, so as to reduce the generation of waste water , Improve economic efficiency, and easy operation

Active Publication Date: 2017-12-08
江苏道尔顿石化科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, in the process of producing paraformaldehyde, formaldehyde will be concentrated and extracted, and a large amount of dilute formaldehyde will be produced. How to deal with dilute formaldehyde has become a difficult problem for paraformaldehyde manufacturers. Most of the disclosed methods are only from the point of view of environmental protection, using chemical conversion method to convert formaldehyde into environmentally acceptable emissions, or using biochemical treatment methods, there are many shortcomings in these methods to deal with dilute formaldehyde: the conversion is not complete, due to side effects When the reaction occurs, part of the formaldehyde is further converted into formaldehyde and formate, so the solution after conversion treatment cannot be discharged directly; formaldehyde is converted into formaldehyde polysaccharides, which cannot be recycled and reused, resulting in waste of resources
In order to increase the concentration of formaldehyde, the existing technology includes distillation or washing, or reacting formaldehyde with alcohol to form hemiacetal. Since the concentration is not high enough, it must be evaporated by heating to obtain formaldehyde-enriched gas. This process requires quite strict reaction conditions. Reaction equipment also requires a lot of energy consumption
[0004] CN102329407A discloses a process for the recycling of dilute formaldehyde produced in the production of paraformaldehyde, breaking the chemical interaction between methanol-formaldehyde, methanol-water and formaldehyde-water-derivatives in formaldehyde wastewater by physical means The relationship between formaldehyde and water has achieved the separation of formaldehyde and water. However, during the concentration process, formaldehyde is easily oxidized to produce formic acid concentration. Reducing the yield of formaldehyde not only affects the production in the subsequent section, but also buryes hidden dangers for long-term stable production. The corrosion of equipment is serious. Equipment maintenance costs a lot

Method used

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  • Device and method for producing concentrated formaldehyde

Examples

Experimental program
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Effect test

Embodiment 1

[0039] A device for producing concentrated formaldehyde, such as figure 1 As shown, it includes: a superheater 3, a catalytic reaction device 4, a steam generator 6 and an absorption tower 7 connected in sequence.

[0040] Wherein, the upstream of the superheater 3 is connected with a methylal vaporizer 2 and a pressurized blower 1; the superheater 3 includes a feeding port arranged in the middle for adding methanol; the inside of the catalytic reaction device 4 includes a fixed bed, a heating device and a heat transfer medium heat transfer oil; a heat exchanger 5 is arranged between the superheater 3 and the steam generator 6; the top of the absorption tower 7 is connected with a tail gas catalytic treatment system 9 and a tail gas circulation device 8, and the tail gas catalytic treatment system 9 is provided with an outlet communicating with the outside world A heat transfer device 10 is provided between the tail gas catalytic treatment system 9 and the steam generator 6; a...

Embodiment 2

[0044] The device is the same as in Example 1, and the heat conduction medium is replaced by molten salt, and the specific parameters are as follows:

[0045] The catalyst in the fixed bed is an iron-molybdenum catalyst, the methylal steam flow rate at the outlet of the methylal vaporizer 2 is 200L / s, the air flow rate at the outlet of the pressurized blower 1 is 2500L / s, and the reaction temperature of the catalytic reaction device 4 is 380°C , the residence time of methylal vapor and air in the catalytic reaction device 4 is 0.28s / time; the temperature at the bottom of the absorption tower 7 is 150°C. The absorbed formaldehyde concentration was 56% by weight.

Embodiment 3

[0047] Device is identical with embodiment 1, and parameter is different, specifically as follows:

[0048] The methylal vapor flow rate at the outlet of the methylal vaporizer 2 is 100L / s, the air flow rate at the outlet of the pressurized blower 1 is 1500L / s, the reaction temperature of the catalytic reaction device 4 is 380°C, and the methylal vapor and air are in the catalytic reaction The residence time in the device 4 is 0.22s / time; the temperature at the bottom of the absorption tower 7 is 120°C. The absorbed formaldehyde concentration was 64 wt%.

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Abstract

The invention relates to a device and a method for producing concentrated formaldehyde. The device comprises a steam overheating unit, a catalytic reaction unit, a steam generation unit and an absorption unit which are sequentially connected, wherein the upstream position of the steam overheating unit is connected with a methylal vaporization unit and an air pressurizing unit. Through reasonable design of the device structure, the yield of 55wt%-70wt% of formaldehyde is 95% or above, and the total conversion rate of formaldehyde and methylal is 99.1% or above; the reaction selectivity of concentrated formaldehyde production is 99.3% or above and the concentration of concentrated formaldehyde is 55% or above. The economic benefit is increased, and the investment and wastewater are reduced. Heat produced in the technological process is self-sufficient, energy consumption is reduced, the technology is simplified, and the operation is more convenient.

Description

technical field [0001] The invention relates to the technical field of chemical production, in particular to a device and method for producing concentrated formaldehyde. Background technique [0002] The production of paraformaldehyde uses formaldehyde as the main raw material. Solid formaldehyde is obtained through evaporation, concentration, and catalytic condensation, and then the finished product is obtained by vacuum drying. However, in the process of producing paraformaldehyde, formaldehyde will be concentrated and extracted, and a large amount of dilute formaldehyde will be produced. How to deal with dilute formaldehyde has become a difficult problem for paraformaldehyde manufacturers. Most of the disclosed methods are only from the point of view of environmental protection, using chemical conversion method to convert formaldehyde into environmentally acceptable emissions, or using biochemical treatment methods, there are many shortcomings in these methods to deal wit...

Claims

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Application Information

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IPC IPC(8): C07C45/32C07C45/78C07C47/04
CPCC07C45/32C07C45/78C07C45/783C07C47/04
Inventor 王雪岭
Owner 江苏道尔顿石化科技有限公司