Method for producing formaldehyde and urea formaldehyde pre-concentrated liquid on super-large scale

Abstract

The invention relates to a method for producing a formaldehyde and urea formaldehyde pre-concentrated liquid. The method comprises steps as follows: S101: methanol is gasified and mixed raw gas is obtained; the mixed raw gas contains methanol with the concentration being 6%-11%, oxygen with the concentration being 9%-13% and the balance of inert gas; S102: the raw gas is sent into a reactor and subjected to a reaction at the temperature of 200-400 DEG C under the action of an iron-molybdenum catalyst; S103: a reaction product is sent into an absorption system to be absorbed by a preset solution, and the formaldehyde or urea formaldehyde pre-concentrated liquid is obtained finally. The provided process for producing oxidation-method (namely, an iron-molybdenum method) formaldehyde on a super-large scale has the outstanding advantages of being high in conversion rate, yield, product concentration and energy recovery degree, excellent in product quality, free of liquid wastes and solid wastes during normal production and the like and is particularly suitable for demands of the large modern chemical industry, the dilemma of extended monopoly of abroad iron-molybdenum method formaldehyde processes is thoroughly broken through, and the blank of the independent intelligent property right of the process in China is filled up.

Description

technical field [0001] The invention relates to the technical field of petrochemical industry, in particular to a method for ultra-large-scale production of formaldehyde and urea-formaldehyde precondensate. Background technique [0002] At present, there are mainly two methods for producing formaldehyde at home and abroad: the silver method and the iron-molybdenum method. The advantages of the silver method are small investment and low power consumption. The disadvantages are high methanol unit consumption, high methanol content in formaldehyde, low formaldehyde concentration (about 37%), and low safety. The maximum capacity of a single device is 120,000 tons. Improvements to the traditional silver method, such as tail gas circulation and flue gas circulation, although this method can increase the concentration of formaldehyde, cannot effectively reduce the methanol content in the product; in addition, if the reaction temperature and oxygen-alcohol ratio are increased to red...

AI Technical Summary

Problems solved by technology

Increased power consumption due to the addition of exhaust gas or flue gas circulation fans

The advantage of the iron-molybdenum method is that the unit consumption of methanol is low, the content of methanol in formaldehyde is low, the concentration of formaldehyde can be adjusted, and the degree of automation is high; the disadvantage is that the acid value of the product is high, the investment is large, the power consumption is high, and the cost is high. It is only suitable for polyoxymethylene, Paraformaldehyde and other fields that use high-concentration formaldehyde as raw materials

[0003] In recent years, with the growing market demand for formaldehyde, especially the demand for high-concentration and high-quality formaldehyde products has increased significantly, the production of formaldehyde by iron-molybdenum method has high conversion rate, high catalyst activity, mild operating conditions, and low methanol content in the product. The product concentration is high, the catalyst is non-toxic and harmless, and it is easy to recycle and reuse. However, the traditional iron-molybdenum process still has relatively serious disadvantages such as large investment, high power consumption, high cost, and limited device capacity.

[0004] Based on this, it is urgent to study a new method that can be effectively used in super-large-scale and high-efficiency production of high-concentration formaldehyde, so as to reduce energy consumption while improving device capacity, and offset the application weakness of large investment with scale effect

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