Formaldehyde production system

Abstract

The invention provides a formaldehyde production system. The system comprises a methanol raw material tank, a methanol intermediate tank, a methanol reboiler, a methanol evaporator, a quaternary mixer, a methanol evaporator, an air heater, a steam filter, a tail gas heater, a filter, an oxidizer, a first absorption tower, a second absorption tower, a tail gas processor, a tail gas heater, and a formaldehyde intermediate tank. The system completes the following steps: (1) evaporation and gas production: obtaining qualified quaternary mixed gas; (2) oxidization: oxidizing and dehydrogenizing methanol in the presence of an electrolytic silver catalyst so as to convert methanol into formaldehyde, wherein a few of byproducts are generated during the process; (3) absorption: taking water and formaldehyde solution as the absorbents, and carrying out continuous counter-current absorption in a packed absorbing tower to produce an industrial formaldehyde solution. The provided system can fully utilize tail gas circulation to produce formaldehyde, the utilization rate of raw materials is high, and little waste is generated.

Description

technical field [0001] The invention belongs to the technical field of chemical production equipment, and mainly relates to a formaldehyde production system that can fully utilize production tail gas. Background technique [0002] At present, there are more than 5,000 formaldehyde production enterprises in China, with a total production capacity of about 32 million tons. Due to the continuous improvement of formaldehyde process technology, formaldehyde has developed from the original "steam consumption type" to "gas production type", that is, all formaldehyde devices can realize by-product steam. Among them, there are two main steam production points of the formaldehyde plant, one is the 0.4MPa steam generated by the reaction heat of the oxidizer, and the other is the pressure-controllable steam produced by the heat of the tail gas combustion of the formaldehyde plant, which generally produces 0.8MPa normally. At the same time, in the formaldehyde production process, additi...

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Problems solved by technology

At present, formaldehyde production enterprises usually decompress the 0.4MPa steam or 0.8MPa steam generated in the formaldehyde reactor to 0.15MPa and then send it into the reactor for batching steam, resulting in direct waste of high-pressure steam energy; and the formaldehyde production in the domestic formaldehyde industry The by-product steam part of the manufacturer has low steam pressure and low usable value, so the by-product steam is basically emptied except for domestic water heating, which is not only noisy, but also a serious energy waste, which does not meet the national energy saving platoon expectations

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