Mitsui Chemicals, Inc.

Kouji Maeba

Masaaki Sasaki

Takashi Yamaguchi

Hirofumi Takahashi

Takuya Saeki

Kouichirou Terada

Takao Naito

Fumiaki Hirata

Masato Saruwatari

Tsugio Imaizumi

Mitsunaga Douzaki

Osamu Hososaka

A polyisocyanate production method that can allow effective use of hydrogen chloride produced secondarily in a polyisocyanate production process, while allowing reduction of environmental burdens, and a polyisocyanate production system for performing the polyisocyanate production method. After chlorine is allowed to react with carbon monoxide to produce carbonyl chloride in a carbonyl chloride producing reactor, the carbonyl chloride produced in the carbonyl chloride producing reactor is allowed to react with polyamine in an isocyanate producing reactor to produce polyisocyanate. Then, after hydrochloric gas produced secondarily in the isocyanate producing reactor is purified in a hydrogen chloride purifying column, the purified hydrochloric gas is oxidized in a hydrogen chloride oxidizing reactor to produce chlorine. Thereafter, the chlorine thus produced is supplied to the carbonyl chloride producing reactor from a chlorine resupply line, so that it is allowed to react with carbon monoxide to produce carbonyl chloride.

Polyisocyanate production method and polyisocyanate production system

An apparatus for continuously producing polyisocyanate is provided for quickly contacting polyamine and carbonyl chloride in order to suppress an undesirable reaction between polyamine and polyisocyanate so that a by-product can be reduced and the yield of polyisocyanate can be improved. In a circulatory line, a material-mixing portion, a high-shear pump, a reactor, a liquid-feeding pumpand a coolerare interposed in series along the direction of the flow of a reaction solution, thereby forming a closed line. In this apparatus, after polyamine and carbonyl chloride are supplied in the material-mixing portion, the reaction solution is sheared by the high-shear pumpin a state where the contact of the polyamine with the reaction solution is minimized. Thus, the formation of a urea compound as a by-product can be suppressed and the yield of polyisocyanate can be improved.

Apparatus for continuously producing polyisocyanate

A polyisocyanate production system is provided that can stably produce chlorine from hydrogen chloride produced secondarily while reacting stably between carbonyl chloride and polyamine and can perform an effective treatment of the hydrochloric gas produced secondarily. A hydrochloric gas control unitcontrols a flow-rate control valveto keep constant an amount of hydrogen chloride supplied from a hydrogen chloride purifying tankto a hydrogen chloride oxidation reactorvia a second hydrochloric-gas connection lineto be constant, and also controls a pressure control valvebased on an inner pressure of the hydrogen chloride purifying tankinput from a pressure sensorto discharge the hydrochloric gas from the hydrogen chloride purifying tankto the hydrogen chloride absorbing columnvia a first hydrochloric-gas connection line, so as to keep an inner pressure of the hydrogen chloride purifying tankto be constant.

Polyisocyanate production system and gas treatment apparatus

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Kamisu, Japan

Kouji Maeba