Wanhua Chemical Group Co., Ltd.

Wanhua Chemical (ningbo) Co., Ltd.

Xiaogao Liu

Hongke Zhang

Weiqi Hua

Jianfeng Chen

Guangwen Chu

Jiansheng Ding

Haikui Zou

Limin Xu

Yu Yao

Bo Zhou

Dongke Zhao

Wenbo Wang

Huihui Wang

Zhenlong Fan

Shuchang Sun

Hua Heng

Junjun Wang

Chong Li

Pengyuan Zhang

Yilu Xia

Meirong Duan

Guiying Niu

Rui Wang

Guanyi Cao

Younian Cao

Xueting Liu

Yabo Ma

Zhenhua Zhao

Ye Zhou

Disclosed is a light colored modified isocyanate mixture and a preparation method thereof. The method comprises the following steps: a) reacting isocyanate groups of a raw material isocyanate under the action of a phospholenecatalyst, and finally obtaining a modified isocyanate reaction solution containing carbodiimide and/or uretonimine derivatives; and b) adding a compounded terminator of a halosilane organic and a sulfonic anhydride to the reaction solution obtained in step a so as to terminate the reaction of carbodiimidization. The modified isocyanate prepared by the method has the characteristics of a liquid state at room temperature, being stable in storage at room temperature and high temperature, and low color number.

Light colored modified isocyanate mixture and preparation method thereof

A method for treating reverse osmosis concentrated water, comprises adding precipitant and oxidant to reverse osmosis concentrated water for treatment, filtering to obtain clear liquid, and adding catalyst for water treatment to clear liquid for catalytic oxidation to obtain a first-stage treated water. Optionally, the liquid may be subjected after catalytic oxidation to an adsorption treatment; performing reverse osmosis treatment on first-stage treated water to obtain second-stage reverse osmosis product water and second-stage reverse osmosis concentrated water; and adding oxidant to second-stage reverse osmosis concentrated water for oxidation treatment to obtain directly discharged effluent water. The obtaining of effluent water may further comprise subjecting liquid after oxidation treatment to adsorption treatment. The above method can recycle 75-85 wt % of water, and operates easily. Thereby, improvement to overall utilization rate of water, and treatment of little remaining water is met to effluent standard for reduction of environmental pollution and economic investment.

Method for treating reverse osmosis concentrated water

The present invention discloses a method of quickly desorbing phosgene from a catalyst in a phosgene synthesizing tower when the catalyst in the phosgene synthesizing tower is replaced. The method is carried out by first purging out easily-desorbed phosgene from the catalyst activated carbon in the phosgene synthesizing tower with nitrogen gas, then purging with ammonia gas, and the ammonia gas is reacted with the hardly-desorbed phosgene in the catalyst of the phosgene synthesizing tower. Then the phosgene synthesizing tower is rinsed with a water gun and then dried with hot gas. The phosgene content at an outlet of the phosgene synthesizing tower after purging is below 0.5 ppm, which can significantly save the time of the phosgene synthesizing tower for purging the phosgene, greatly reduce the amount of nitrogen gas consumed, and improve the safety of the process operation.

Method for replacement of phosgene synthesis column catalyst

The invention relates to a method of circular use of waste brine produced in the manufacture process of MDI, comprising the following steps: (1) the waste brine produced in the manufacture process of MDI is subjected to a high-gravity extraction and then to a column extraction, wherein said waste brine contains aniline, diaminodiphenylmethane and polyamine; (2) the waste brine from step (1) is transmitted to a stripping tower for steam stripping; (3) the waste brine from the stripping tower of step (2) and a chemical oxidant are transmitted to an oxidation reactor to which air is blown for aeration; (4) the waste brine after the treatment of step (3) is transmitted to an absorption tower for absorption. The invention makes the salt water have TOC of less than 8 ppm and TN of less than 2.5 ppm and achieves regeneration of resources in the waste brine such as sodium chloride and water and the like for circular use.

Method for treating waste saline water produced in production process of diphenylmethane diisocyanate (MDI)

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Shandong, China

Xiaogao Liu