Operation and automation of polysilicon reduction furnaces

It’s completely possible; in fact, that’s exactly how it’s done.

The prerequisite for achieving chain operation is that all instruments must be highly accurate; however, many instruments currently exhibit inaccuracies at low flow rates. Moreover, who can guarantee the accuracy of the temperatures measured by infrared thermometers used to measure silicon rods? The experience of experienced technicians is still needed

What we can do now is achieve automatic interlocked control of temperature and current, but not of the feed rate, as the flow meter for feeding is inaccurate; if the flow meter were accurate, interlocked control could be implemented.

Under normal conditions, it is not linked to the feed rate; fluctuations in flow rate affect the growth of silicon rods.

In fact, the views from the third, fourth, and fifth floors combined already provide a fairly comprehensive overview. If all the above conditions are met, automatic control can be achieved; however, as of now, there are hardly any companies in China that are capable of implementing such automatic control.

Achieving automatic control is an inevitable trend; otherwise, what is produced will be only at the level of solar energy technologies. Electronics present great challenges

:handshake:handshake:handshake – it gets straight to the point; the accuracy of the instruments is the real issue

No one can guarantee the accuracy of the temperatures measured by infrared thermometers used to measure silicon rods; the workers’ experience is very important.

Well, I hope everyone will take a look at what “interlocking” means. What parameters are used to adjust the TCS feed rate and the instantaneous current level? Based on the temperature of the rod’s surface? Assuming the accuracy of the infrared sensor is very good, the current temperature of the rod is 1100°C. If there are fluctuations, whether it’s in automatic or manual mode, should the current be adjusted or something else? Another one is the TCS feed; what determines its size? It should be the diameter of the rod, but this is usually determined visually, and the diameters of the rod on the inside, outside, and in between are all different. So how is the size of TCS determined? Generally, foreign furnaces have a growth curve; at a certain point during this growth process, the values of current, TCS, and H2 are fixed. In other words, when operating automatically, the SP values for these parameters are known. But why is automatic control so rarely used in domestic polysilicon production, especially during the reduction process? Please everyone share your thoughts.

That temperature is just a reference value; after all this time of production, can’t you even create a menu for current control? If that’s really the case, then your engineers are terrible. You could consider asking me to go, hehe

I would like to ask whether the scope of supply for furnaces abroad includes the process curves. So, values such as current, TCS, and H2 levels at certain points during the growth process being fixed – are these provided to domestic manufacturers? Do they then make adjustments based on their own processes?