Environment-friendly formaldehyde preparation process

Abstract

The invention relates to the field of chemical production, and in particular relates to an environment-friendly formaldehyde preparation process which comprises the following steps: gasifying methanol, mixing with air, and conveying the mixed gas into a preheater, wherein the preheating temperature is 100 DEG C; then reacting, wherein the temperature inside a reactor is 200 DEG C, an iron-molybdenum catalyst is used as a catalyst, and the reaction time is 2-5 minutes; keeping the temperature inside the reactor to be 270-300 DEG C, reducing the temperature of formaldehyde discharged from the reactor to 100-120 DEG C, feeding into an absorbing tower, diluting inside the absorbing tower, sucking out when the concentration is 37-50%, circulating 20% of formaldehyde back to the absorbing tower, and pumping the other part of formaldehyde as a product to a formaldehyde storage tank; recycling 60-90% of the gas discharged from the top of the absorbing tower by using a blower; and feeding the other part of the gas into a tail gas reactor for oxidation reaction at 200-300 DEG C. According to the process, the heat in production is sufficiently utilized, the parameters are strictly controlled, the methanol conversion rate of the process is greater than 98%, the purity of formaldehyde is 37-50%, the content of formaldehyde, methanol and carbon monoxide in the tail gas is all zero, and the content of carbon dioxide is also effectively controlled.

Description

technical field [0001] The invention relates to the field of chemical production, in particular to an environmentally friendly formaldehyde preparation process. Background technique [0002] Formaldehyde is a colorless aqueous solution or gas. Has a pungent odor. It can be miscible with water, ethanol, acetone and other organic solvents in any proportion. The liquid tends to become turbid when it is stored for a long time when it is cold, and it will form a paraformaldehyde precipitate at a low temperature. When evaporating, a part of formaldehyde escapes, but most of it turns into paraformaldehyde. This product is a strong reducing agent, and its reducibility is stronger when it is slightly alkaline. It can be slowly oxidized to formic acid in air. [0003] Formaldehyde has a wide range of uses, and about 65% of its consumption is used to produce formaldehyde resins, mainly urea-formaldehyde resins (adhesives, aminoplasts), phenolic resins (adhesives, phenolic plastics...

AI Technical Summary

Problems solved by technology

The formaldehyde plant using the iron-molybdenum catalyst process generally has a large production capacity and a high conversion rate of methanol, but the purity is low, generally 20-30%, and the heat energy waste in production is serious, and the tail gas treatment is difficult, and the methanol consumption is low. High concentration formaldehyde can be produced without distillation device, low alcohol content in formaldehyde finished product, long service life of catalyst, large one-time investment and high power consumption

The silver method has simple process, low investment, strong adjustment ability, and less formic acid content in the product, but the methanol conversion rate is low, the unit consumption is high, the catalyst life is short, the purity of methanol is high, and the methanol content in the finished formaldehyde product is high, so it can only produce low concentration. formaldehyde

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