Ultrahigh-scale formaldehyde production method and system

Abstract

The invention discloses an ultrahigh-scale formaldehyde production method and system. The production method comprises the following steps: mixing a gas mixture of methyl alcohol steam from an evaporator, water steam, formaldehyde steam and air with a part of water steam; passing by a heater and a filter and then entering an oxygenizer; reacting and generating formaldehyde and other side products under the conditions that the temperature is 590-625 DEG C and the mole ratio of oxygen to methyl alcohol is 0.33-0.37 and under the effect of a silver catalyst in the oxygenizer; dealcoholizing and absorbing the high-temperature reaction generated gas by a first absorbing tower and a second absorbing tower in turn; extracting the product from the bottom of the first absorbing tower; supplementing some absorbing liquid extracted from the bottom of the second absorbing tower and returning into the evaporator; and guiding the dealcoholized tail gas in high hydrogen content into a tail gas processor, burning and recycling the waste heat. In the ultrahigh-scale formaldehyde production method provided by the invention, a lower mole ratio of oxygen to methyl alcohol and lower reaction temperature are set, so that the ratio of dehydrogenation reaction can approach to 48-50%.

Description

technical field [0001] The invention relates to the technical field of formaldehyde production, in particular to a method and system for producing ultra-large-scale formaldehyde. 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 a single set of equipment with a small capacity of 120,000 tons. Improvements to the traditional silver method, such as tail gas circulation and flue gas circulation, although these two methods can increase the concentration of formaldehyde, they fail to effectively reduce the methanol content of the product. If the reaction temperature and oxygen-alcohol ratio are increased to reduce A higher methanol content wi...

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Problems solved by technology

To achieve this, China's diesel consumption is 150 million tons, and adding 10% of the amount is 15 million tons, and the PODE plant needs to be launched to have a production capacity of 100,000 to 300,000 tons, and a 100,000-ton production capacity device needs It needs to be equipped with 250,000 tons of formaldehyde, and the conventional domestic silver method device requires three sets of 80,000-100,000 tons of equipment. The construction is too wasteful, and it is likely to be replaced by foreign 240,000-280,000 tons of iron-molybdenum method formaldehyde devices

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