Design your mission

This topic is for Shanghai huayi energy chemical industry co。, LTD。 And design the technological process of the research design, formaldehyde as an important chemical raw material used in chemical industry, pesticide and wood, etc can be synthetic pesticides, disinfectant, dye, timber, application is very extensive, the various countries' to formaldehyde in consumption is enormous, so experts at home and abroad dedicated to the research and application of iron molybdenum catalyst method has obtained many achievements。

Design standards

This design reference for the related to chemical engineering design standards and regulations of the state, to determine the formaldehyde synthesis process route, process flow and process parameters of process route selection:

(1) excess methanol excessive oxidation of methanol oxidation silver catalytic oxidation method, namely catalyst for silver or silver particle layer, need to methanol, excessive reaction temperature is about overland ℃。The conversion rate of formaldehyde is not high, but the single consumption is very high, so it is mainly used in the production of low concentration of formaldehyde solution。

(2) the air excess oxidation method is also known as iron molybdenum catalytic oxidation, and its process is to react under the condition of insufficient methanol and excess air。General using Fe2O3, MoO3 as catalyst, and join the chromium and cobalt oxide as catalyst promoter, generally in three or four baidu more high concentration formaldehyde solution under the temperature of reaction system。   

(3) the methylal oxidation process, a high concentration of formaldehyde is first to formaldehyde and methanol under the catalysis of cation exchange resin catalyst for synthesis of methylal, methylal on iron, aluminium oxide catalytic, under the action of recycled air oxidation to formaldehyde, but the methylal oxidation reaction is included many complex series of reactions, parallel processing technology is extremely complex, difficult to produce。

(4) exhaust gas cycling are using the latest foreign technology production of formaldehyde using silver "formaldehyde method of exhaust gas cycling," product quality standard is far higher than before, to retain more than four hundred kg/t production unit consumption, methanol by vaporizing become methanol steam after heating, the electronic control system according to its oxygen alcohol than the value of the real-time control of reaction temperature, ensure optimum reaction operation。In the process, the exhaust cycle method is adopted, so the heat is taken away from the circulation。

Process determination

This design for the annual output of 80000 t process of methanol to formaldehyde, finally calculated the results analysis, the process to consider using multiple reactor simultaneously, so the relevant operation process can be pided into five parts。In order to facilitate the narration, the various sections of the process are specified。

Hybrid section

Raw materials for filtering air after filtering air preheater, after preheating with gas phase methanol from methanol evaporator in pipeline mixer to mix, blend of feed gas into the feed preheating section for preheating temperature。

Evaporation section

Methanol by the centrifugal pump to the high tank, in under the action of gravity flow into the methanol evaporator evaporation vaporization, heat of vaporization from the reaction product of high temperature, after vaporization of methanol into the air mixed with the raw material mixing ratio section。

Preheating section

Heat transfer from the heat exchanger to heat exchanger, the heating medium is derived from the reactor, the product is cooled after heat exchanger。After the heating, the gas enters the oxidation reaction section and reacts。

The reaction section

Feed gas into the reactor by preheating section for reaction, and then in a fixed bed partial oxidation iron molybdenum catalyst surface, under the condition of the methanol reaction of formaldehyde。Most of the formaldehyde produced by the reaction, as well as a small amount of CO, CO2, H2, formic acid, and raw material gas, are combined with the incoming feedstock to heat and cool the incoming materials。