Continuous production system for preparing high-quality formic acid by acidifying sodium formate with polyphosphoric acid

Abstract

The invention discloses a continuous production system for preparing high-quality formic acid by acidifying sodium formate with polyphosphoric acid. The continuous production system is characterized in that the tops of multiple raw material premixing tanks are separately provided with three inlets, and the three inlets are separately connected with a sodium formate storage tank through respectivescrew feeders, a polyphosphoric acid storage tank through a first conveying pump and a formic acid auxiliary agent storage tank through a second conveying pump; the bottom outlets of the multiple rawmaterial premixing tanks are connected with a multi-stage acidification reaction kettle through a third conveying pump; the top of the reaction kettle is connected with a first condenser, and the bottom is connected with a normal-pressure distillation unit through a fourth conveying pump; the normal-pressure distillation unit is connected with a decompressing distillation unit; the decompressing distillation unit is connected with a formic acid product storage tank through a vacuum pump and a second condenser; the normal-pressure distillation unit is also connected with the formic acid product storage tank through a third condenser; and the bottom of the decompressing distillation unit is connected with a compound sodium phosphate salt storage tank. In the continuous production system disclosed by the invention, high-quality formic acid is prepared by acidifying sodium formate from yellow phosphorus tail gas, thereby eliminating pollution, changing waste into valuable and acquiring a useful product.

Description

technical field [0001] The invention relates to a resource recovery and utilization system of yellow phosphorus tail gas, in particular to a continuous production system for producing high-quality formic acid by acidifying sodium formate with polyphosphoric acid. Background technique [0002] my country has the most abundant phosphate rock resources in the world, and the reserves, output and market share of yellow phosphorus rank first in the world. Generally, for every ton of yellow phosphorus produced, about 2800~3000m of by-products 3 The main component of these tail gases is carbon monoxide, accounting for 87-92% of the total mass fraction, and the remaining impurities are mainly sulfides, phosphides and ash, etc., and the calorific value of the tail gas is 1.05-1.1x10 7 J / m 3 . Due to the complex composition of yellow phosphorus tail gas, the difficulty of purification and the high investment, most enterprises directly burn the tail gas. On the one hand, this causes...

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Problems solved by technology

This method of batch production of formic acid, on the one hand, requires more manpower to participate, complicates the operation, increases the cost and the probability of misoperation, and limits the production capacity of formic acid, which can only meet the needs of small-scale production, which is not conducive to Resource recovery of a large amount of yellow phosphorus tail gas

At the same time, the following problems generally exist or are avoided in the prior art: (1) The change of the viscosity of the system during the production process is not fully considered

As mentioned above, in the production process, regardless of the reaction process or the distillation process, the viscosity of the material system changes from thick to thin, or from thin to thicker, and the requirements for system power are not the same. Obviously, according to the maximum The selection of power or minimum power will cause a mismatch between the equipment and the material system, which will lead to unreasonable energy utilization of the system; (3) None of them involve the equipment factors of process realization

Factors affecting the concentration and yield of formic acid include raw material ratio, reaction temperature, system pressure, etc., and the realization and stability of these factors must be completed by equipment. Therefore, the development of fully functional, reasonable and efficient equipment has become the realization of the entire process technology. important and difficult points, but the existing technology is rarely involved in this

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