New ammonium chloride decomposition method "marriage" soda chlor-alkali

Sinochem New Network News On July 31, the new ammonium chloride decomposition method was successfully tested in Nanchang Zhixin Chemical Technology Co., Ltd. The technology can directly decompose ammonium chloride to recover ammonia to obtain hydrogen chloride, and solve the key problems of the two major soda ash processes of ammonia alkali method and combined alkali method, and obtain cheap dry hydrogen chloride for co-production of PVC or trichlorosilane and various organic Chlorine products not only avoid pollution but also increase the value of chlorine. This technology will advance the technological advancement of the soda ash process and achieve a “marriage” between the soda ash and the chlor-alkali industry.

Advances in the soda ash manufacturing process are closely related to the way ammonium chloride is disposed. The ammonia-alkali method uses lime milk to decompose ammonium chloride to recover ammonia, thereby producing a large amount of calcium chloride waste liquid; the alkali-alkali method adopts salting-out and cold precipitation to recover ammonium chloride from the mother liquid, and ammonium chloride is sold as a product, although chlorine is eliminated. Calcium waste liquid and its pollution, but the combined output ratio of ammonium chloride to soda ash is as high as 1:1, and the ammonium chloride is surplus, and the market prospect is bleak.

"Our idea is to directly decompose ammonium chloride to recover ammonia and obtain hydrogen chloride without using lime milk. For the ammonia-base method, calcium chloride waste liquid will not be produced without lime milk; There is no problem of excess ammonium chloride." Zhang Zhixin, a research and development leader of the technology and a senior engineer of Zhixin Chemical, told the reporter.

According to Zhang Zhixin, he developed the patented ammonium chloride decomposition method in the 1990s. However, the hydrogen chloride obtained by this process has a strong corrosive property at a high temperature of 350 ° C, and it is difficult to be applied to industrial production.

To this end, after years of careful research, he finally made a breakthrough in the original decomposition catalyst, forming the current new ammonium chloride decomposition method. After the original catalyst is modified, not only the ammonium chloride decomposition temperature is lower (130 ° C ~ 300 ° C), the rate of ammonia release or hydrogen chloride is faster, and thus the energy consumption is lower. The new process is also greatly simplified, and the indispensable processes such as dissolution separation and catalyst regeneration can be omitted.

Zhang Zhixin believes that the new ammonium chloride decomposition method is also special in that the decomposition reactor can be made of ordinary carbon steel. The ammonia or hydrogen chloride is not corrosive to carbon steel, and the reactor is not only low in cost but also very durable. Entering the reactor may be an ammonium chloride solution, which releases water vapor with water vapor, does not affect the return to the next step reaction; the hydrogen chloride is completely dry, and the dry hydrogen chloride not only does not corrode the equipment but is also very advantageous for its utilization. Therefore, the process and equipment of the new ammonium chloride decomposition process are easy to implement in industrial production.

Zhang Zhixin said that the dry hydrogen chloride directly obtained by the new ammonium chloride decomposition method can be used to manufacture PVC, trichlorosilane, chlorosulfonic acid and various organic chlorine products, and the utilization value of chlorine is much higher than that of producing only ammonium chloride. The production of soda ash after the new ammonium chloride decomposition method completely eliminates the disadvantages of ammonia or alkali, and realizes the co-production of soda ash and dry hydrogen chloride, greatly improving the utilization value of chlorine, and no longer need lime or ammonia. It can be sold or processed into other products, and the economic benefits of the device are greatly improved.