Should the CVD exhaust gas recovery process use CDI or domestically produced solutions?
Thread Content
Let’s discuss this: regarding the technology used in CVD tail gas recovery systems, among the polysilicon projects that are currently in operation or under construction, aside from those using CDI technology, which manufacturers are employing domestic processing technologies? How is it working? What are the shortcomings of CDI? What are the shortcomings of domestic products? Can domestically produced key carbon adsorbents replace imported ones? It affects production costs! Those with practical experience, please share your insights! Let’s all discuss more too!
Tail gas recovery mainly relies on CDI, right? In China, the systems that are fairly good are also mostly improvements based on CDI. Carbon adsorbents? Are you referring to activated carbon? It seems that using domestic versions of it should work fine as well
Domestically produced coconut shell activated carbon is also widely used in CDI, with fairly good results. For further discussions, please contact me at 18733376766＠139.com
CDI technology, domestic equipment – of course, activated carbon is available domestically without any issues!
Regarding the recovery of polysilicon exhaust gases, Sichuan Yalian Technology possesses a patented technology that offers better results and is more cost-effective than CDI in smaller-scale projects; the exhaust gas recovery system used in the polysilicon project at Leshan Yongxiang is an example of such an application； However, I am not an engineer. If the original poster is interested in learning more details, they can contact 13708028844 or send an email to 13708028844@139.com
Reply to 6# xv4321: It seems that Zhongsi is doing pretty well at the moment; it’s probably their own developed technology. Just trying to contribute something here~!
Reply 1# jzppzj [/b Differences between the CDI process and domestic processes: 1) The adsorption column in CDI uses temperature- and pressure-variable adsorption, and specific requirements exist regarding temperature and pressure changes during regeneration. And the domestic process is only pressure swing adsorption. 2) The CDI process is used to separate hydrogen chloride and recover it. The domestic process does not recover hydrogen chloride; it is treated through leaching (for waste treatment). 3) The CDI process uses compressed exhaust gas only for absorbing hydrogen chloride and for pressure swing adsorption. The domestic process uses a vacuum pump for adsorbent regeneration, and compression is also required to increase pressure. 4) The hydrogen chloride content in the recovered chlorosilane liquid from the CDI process is very low, while it is relatively high in the chlorosilane liquid from domestic processes, which has a certain impact on the operation of the distillation tower.
Reply to 8# Absorption tower: From what you’ve described, domestic versions have complex manufacturing processes, low recovery efficiency, and high production costs. Do domestic options really have no other advantages apart from lower investment costs?
Reply to 8#: I can’t entirely agree with the view on the absorption tower; it seems that there is a lack of full understanding of domestic recycling processes. As far as I know, current domestic manufacturing processes can achieve complete zero emissions, with no issues related to the treatment of waste materials ； It is also well known that PSA technology has been used in hydrogen purification systems in China for over 30 years; however, there is no record of TSA being used solely for hydrogen purification, unless the gas source composition is simple. In other words, in situations with complex gas compositions and high requirements for hydrogen purity, the product purity achievable using PSA technology is necessarily higher than that achieved with TSA technology. These are my humble opinions; I welcome any criticism and suggestions from everyone.
On the attic； Our dedicated method is PSA+TSA, which is almost a full cycle.
To sum up: Technology still has an absolute advantage over CDI, and domestic alternatives can be considered for activated carbon adsorbents. There are new suggestions; let’s keep discussing!