Dimethyl oxalate falling-film evaporator for synthesis of oxamide

Abstract

The invention relates to a dimethyl oxalate falling-film evaporator for synthesis of oxamide. The falling-film evaporator comprises a shell, an overflow ring groove, a falling-film evaporator shell pass group and a gas-liquid separator, the top of the shell is provided with a feed inlet, and the bottom is provided with a discharge port and a nitrogen inlet, the falling-film evaporator shell pass group is arranged in the shell, and an exhaust funnel covers the top of the falling-film evaporator shell pass group, the falling-film evaporator shell pass group comprises a plurality of falling-filmevaporator shell passes uniformly arranged in the shell, the overflow ring groove is sleeved to the upper part of the exhaust funnel and is located below the feed inlet of the shell, the gas-liquid separator is disposed outside the shell, the top of the gas-liquid separator is communicated with an inlet at the upper part of the falling-film evaporator shell pass, and the bottom of the gas-liquid separator is communicated with an outlet at the bottom of the falling-film evaporator shell pass. The dimethyl oxalate falling-film evaporator for synthesis of oxamide provided by the invention can change the heating rate by adjusting the liquid level of steam condensate in the gas-liquid separator so as to change the evaporation rate of dimethyl oxalate, and reaches the purposes of adjusting the purity and productivity of oxamide, and has the characteristics of simple structure, low manufacturing cost, convenient operation and excellent effect.

Description

technical field [0001] The invention relates to a falling film evaporator, in particular to a dimethyl oxalate falling film evaporator used for synthesizing oxamide. Background technique [0002] Oxalamide is a white powder with nitrogen content of 31.8%. It does not absorb moisture in the air, is non-toxic, and is easy to store. The solubility in water is 0.016%. During hydrolysis or biodegradation, ammoniacal nitrogen is gradually released. And carbon dioxide, is a good urea-formaldehyde slow-release fertilizer. [0003] There is a dimethyl oxalate ammonolysis method in the synthetic route of oxamide. The mixed gas of dimethyl oxalate gas and nitrogen is mixed in the reactor, and the dimethyl oxalate reacts with nitrogen to generate oxamide solid powder and methanol gas. Since nitrogen is easier to separate from the reaction product system, the reaction system often uses excess nitrogen. Most of the existing dimethyl oxalate factories are built as supporting facilities ...

AI Technical Summary

Problems solved by technology

[0004] In the prior art, falling film evaporators for regulating the evaporation of dimethyl oxalate have high manufacturing cost, poor effect, and inconvenient adjustment of production capacity. Therefore, there is an urgent need for a falling film evaporator with simple structure, low manufacturing cost and good effect.

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