Continuous co-production method for high concentration formic acid and high pure sodium hexametaphosphate

Abstract

The invention relates to a continuous preparation method of concentrated formic acid with joint production of high pure hexametaphosphate, which comprises that peroxyphosphoric acid and sodium formate are simultaneously put into a cone-type mixer to be mixed uniformly and reacted instantly, the generated formic acid presses generated mixed materials into a distillation drier to be distilled and dried into dry powder of composite phosphate, the generated formic acid gas is fed into a washing dewatering purifier, to be washed, purified and dewatered via peroxyphosphoric acid to be fed into a condenser to separate formic acid, the condensation temperature is controlled to obtain concentrated formic acid, the foul gas is pumped out under vacuum, the generated dry powder of composite phosphate automatically flows out from the distillation drier, to be directly fed into a polyfurnace or first prepared into solution to be fed into a polyfurnace, continuously adds industrial phosphoric acid, obtains high pure hexametaphosphate. The invention has high production efficiency, reduced acidification reactor, continuous operation, large production capacity, non formic acid gas leakage in process, improved workshop environment, high product yield, high formic acid density, better economic and environment benefits.

Description

technical field [0001] The present invention relates to aliphatic carboxylic acid and alkali metal phosphate, specifically, relates to the preparation method of formic acid and phosphate sodium salt. Background technique [0002] The method for preparing formic acid and co-producing sodium hexametaphosphate has been published in the world with the ZL97103209.2 patent. However, this method has the following disadvantages: the one is that the technological process is discontinuous, and the processes of acidifying sodium formate with superphosphoric acid and producing formic acid are all completed intermittently; Feeding, after about 15 minutes of mixing reaction under stirring, can enter the distillation process; third, because the acidification reaction releases a large amount of reaction heat, formic acid gas overflows and pollutes the environment, even if measures such as jacket cooling and vacuum absorption are used, the effect is not ideal; The first is that the yield of...

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Problems solved by technology

However, this method has the following disadvantages: the one is that the technological process is discontinuous, and the processes of acidifying sodium formate with superphosphoric acid and producing formic acid are all completed intermittently; Feeding, after about 15 minutes of mixing reaction under stirring, can enter the distillation process; third, because the acidification reaction releases a large amount of reaction heat, formic acid gas overflows and pollutes the environment, even if measures such as jacket cooling and vacuum absorption are used, the effect is not ideal; The first is that the yield of formic acid is low, the whole production process takes 2 to 2.5 hours, and the production efficiency is low; the fifth is that the concentration of formic acid produced is mostly only 85%, because the moisture in the formic acid gas distilled has not been removed, so the obtained There is very little high-concentration formic acid, and its added value cannot be increased

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