After the explosion at GCL: Why a safety program is necessary

Distillation columns of GCL-Poly’s polysilicon plant in Xinjiang
An easily inflammable resin in the distillation unit may have caused the explosion at GCL’s polysilicon plant in Xinjiang – Image: Energy1

By Alan Crawford, Methylchlorosilanes and Trichlorosilane Process Consultant

The recent significant process safety incidents at polysilicon plants in China – at Daqo, GCL and East Hope since early July 2020 and Tongwei Group in 2019 – are very troubling. Few details, such as injuries, fatalities and root cause, are available about these incidents. They are troubling not only because of immediate impact to the workers and their families along with members of the local communities but also because of potential impact to the reputation of the global solar-grade polysilicon industry.

I have worked as a chemical engineer in the global silicones and polysilicon industries since 1989. My focus has been on the technical side of metallurgical-grade silicon procurement, silicon grinding and conversion of silicon to methylchlorosilanes and trichlorosilane. I worked for GE Silicones (now Momentive Performance Materials) from 1989 to 2004 and Advanced Silicon Materials/REC Silicon from 2004 to 2008. Since 2008 I have been active as an independent engineering consultant. One area I have invested considerable time through the years has been process safety.

As we all know, polysilicon is the starting point for production of almost all solar panels. Renewable energy through solar is marketed as a clean alternative to fossil fuel energy sources. These Chinese incidents have the potential to hurt the public image of the global solar industry.

While it is easy for us to collectively dismiss these as “Chinese problems”, this is a poor line of thinking. Polysilicon plants can be and are safely designed and operated around the world, but they are complex chemical operations that do handle dangerous intermediate materials in order to produce such a safe and inert final product. All global producers must be continually aware of the hazards that exist and must never relax when it comes to process safety.

The positive example of the silicones industry

The legacy global silicones industry (in the USA, Western Europe and Japan) has an umbrella organization known as the Global Silicones Council (GSC). The GSC serves many purposes but one is to enable exchange of relevant process safety information across all participating silicone producers. When I worked for GE Silicones in the 1990s, there was a large GSC-sponsored initiative to take a hard look at process safety in the areas of silicone production from metallurgical-grade silicon grinding through production of siloxanes.

The reason for this initiative was to share relevant process safety information with all producers in an effort to minimize the chance that a major incident occurs. Such an incident was viewed as harmful to the entire silicone industry. The GSC was the organization that enabled this series of open intra-industry process safety discussions (and proved that competitors could and did have open discussions about process safety without violating proprietary technology property rights or anti-trust/anti-competition laws).

The recent explosion at Xinjiang GCL can be argued as just such an incident that the silicone producers were trying to prevent back in the 1990s.

What can be done to help improve the safety of these large Chinese plants? In recent years, the Chinese government has finally taken an aggressive approach to fixing the widespread environmental emission problems associated with the entire chemical industry. One can hope that similar attention will be placed on process safety now. But, for the benefit of the global polysilicon industry, a more focused and specific program is necessary.

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