After the flood, Tongwei’s polysilicon plant shut for two months

After a once-in-a-century flood in mid-August, the older polysilicon plant of Tongwei with a capacity of 20,000 metric tons in Leshan, Sichuan province will remain out of operation until mid-October. Chinese media quoted the company’s investor relations department as saying that the production downtime would be about two months.

The plant of Tongwei’s subsidiary Sichuan Yongxiang Polysilicon was shut down on August 18 when the local emergency management bureau ordered the company to stop production immediately. According to Tongwei, the main production equipment was not damaged during the flooding. Yongxiang has started to clean the site and to inspect the equipment; it is also talking to the insurance company about claims related to the loss from suspended production.

Although the flood began to recede on August 19, the factory was without electricity and water supply on the morning of the 20th. As a consequence, the vent gas rinsing system did not work normally; gas that could not be absorbed was emitted into the air, forming thick fog containing irritating hydrogen chloride.

While local authorities downplayed the incident, it caused a mass exodus of concerned residents on the streets of Leshan. A western expert told Bernreuter Research that the gas leak was a “worst-case scenario.” Best practice would dictate an emergency scrubber with pumps powered by backup generators, he said.

It was not the first incident that occurred at Tongwei’s polysilicon plants:

• May 23, 2013: A heat exchanger in the hydrogenation unit of Yongxiang Polysilicon leaks and ignites spontaneously, producing toxic fumes.
• July 13, 2015: The failing pump at a distillation column of Yongxiang Polysilicon causes a chlorosilane leak and combustion, resulting in a huge vapor plume containing hydrogen chloride.
• April 13, 2019: At Tongwei’s new polysilicon plant in Baotou, Inner Mongolia, a valve in the adsorption system of the distillation unit leaks and catches fire, which is extinguished after three hours.

The series of incidents once again underscores why a safety program is necessary in the Chinese polysilicon industry.