SU502864A1 - Method for producing formaldehyde - Google Patents

Description

one

A known method of producing formaldehyde by oxidizing methanol with air on molybdenum-containing catalysts at 130-400 ° C and an oxygen-to-methanol ratio of more than 0.6.

The disadvantage of this method is the low productivity of the reactor associated with the content of methanol in the mixture (not more than 6.5% at temperatures above 150 ° C). The concentration of methanol in the starting mixture cannot be increased, as this mixture becomes explosive.

In order to eliminate these drawbacks, it is proposed to add 10-25% to meta. % methane. The maximum methanol content in the mixture at which it will be explosive is 23%. As a result, it is possible to increase the productivity of the reactor in formaldehyde by a factor of 2.2 compared with the known method. Since the reaction gases leave the reactor before they enter the heat exchanger for some time at high temperatures, ignition may also occur here. In order to prevent ignition, one can additionally introduce meta under the catalyst at the outlet of the Layer.

Example 1. 1200 kg of an iron-molybdenum catalyst with a grain size of 3.0-3.5x3.0-3.5 mm and an atomic ratio Mo: Fe 2.3-2.5 and 700 kg of an iron-molybdenum catalyst with an atomic ratio Mo: Fe I, 7-1.8 and a particle size of 1.4-1.8X10-20 M: M are loaded into the adiabatic layer. A mixture of composition,%: 16 methanol, 14 oxygen, is fed to the reactor.

52.7 nitrogen and 17.3 methane at a temperature of 130-150 ° C in the amount of 8780. At the exit from the tubular part of the reactor, there is a mixer in front of the adiabatic layer, to which 700 methane is added. At the exit of the reactor, the expected total conversion of methanol is 98-99%, and the yield of formaldehyde is 92-94%.

The heat of reaction in the tubular part is removed by mineral oil circulating between the tubes with a temperature of 230-260 ° C. At the outlet of the adiabatic layer, the reaction gas, having a temperature of 320-340 ° C, is cooled in a heat exchanger to 120-140 ° C. ;.; then fed to the absorption column, from

which take formalin with a concentration of 37-50%.

Claims (1)

Invention Formula The method of producing formaldehyde by oxidizing methanol with air on molybda:; 3 containing catalysts at 130-400 ° C with a ratio of oxygen to methanol over 0.6, characterized in that 10 25 about % methane.