Double effect process rectification diaminotoluene separation method

A technology of diaminotoluene and a separation method is applied in the field of separation of diaminotoluene by double-effect process rectification, which can solve the problems of increased tower heat load, large energy consumption, multi-high pressure steam, etc. The effect of reducing the heat load of the tower and reducing the difficulty of separation

Inactive Publication Date: 2009-01-21
GANSU YINGUANG CHEM IND GRP CO LTD
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Problems solved by technology

[0003] The traditional multi-tower continuous distillation process is commonly used in the separation of TDA. Through analysis, it is found that although the temperature at the bottom of the dehydration tower reaches 210°C, the water content in the bottom stream is relatively high, which not only reduces the concentration of ortho isomers at the top

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  • Double effect process rectification diaminotoluene separation method

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[0008] The present invention is characterized in that the crude TDA material containing water, solvent and tar is first dehydrated, then the solvent is removed, and then the TDA containing tar is subjected to isomer separation to remove ortho-position TDA and meta-position TDA, and finally obtain pure TDA, the solvent can be recycled.

[0009] As shown in Figure 1, concrete steps of the present invention are: the thick TDA material that contains water, solvent and tar enters dehydration tower (T11) dehydration from the bottom of the tower, then, part material directly enters desolventization tower (T20) from tower top, Most of the remaining materials are separated from the bottom of the tower through the dehydration tower (T12), and then the materials containing TDA and tar are discharged from the bottom of the tower, and then enter the first isomer separation tower (T30). (T30) tower top removes ortho-position TDA, then, the material containing a small amount of residue and p...

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Abstract

A method for separating diaminotoluene through double-effect flow rectification belongs to the rectification process optimization field with better energy conservation and consumption reduction effect. The method comprises the following steps that a coarse TDA material containing water, solvent and tar is dewatered at first; then, the solvent is removed and then the TDA containing tar undergoes isomer separation so as to remove ortho position TDA and meta position TDA; and finally, pure TDA is obtained.

Description

technical field [0001] The invention relates to a separation method for rectifying diaminotoluene (TDA) in a double-effect flow process, and belongs to the field of rectification process optimization with great energy-saving and consumption-reducing effects Background technique [0002] The product quality of diaminotoluene (TDA) directly affects the production and separation process of toluene diisocyanate (TDI) and the quality of the final product. In the production process of TDA, the crude TDA obtained by hydrogenation of dinitrotoluene (DNT) contains water, solvent, meta-TDA, ortho-TDA, residue and traces of para-TDA, wherein water, solvent and residue must be removed . Ortho TDA reacts with phosgene not to generate isocyanate, but to generate cyclic urea and its polymers, which are easy to cause precipitation and blockage, and must be removed. In the traditional refining process of TDA, the process that consumes the most energy is the process of crude TDA dehydration...

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Application Information

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IPC IPC(8): C07C209/86C07C211/51
Inventor 李玉刚李晓明郑世清张伟谭心舜李春欣
Owner GANSU YINGUANG CHEM IND GRP CO LTD
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