The listed contaminants and impurities will affect production standard, and reduce heat transfer efficiency. Efficient filtration and separation equipment not only ensures good safety production equipment technology, and also improves product yield. With the combined experience attained from many projects, Feature-Tec is able to present our filtration technology solutions.

High Temperature Exhaust Gas Purification

In the polysilicon production technology, exhaust filtration plays an important role, especially during a bad market situation to reduce costs in producing polysilicon products.

A. Waste gas/liquid separation of flue gas.

B. Reduction reaction of furnace/exhaust gas.

C. Hydrogenated furnace exhaust gas separation.

D. Silicon powder tank silicon powder filtering etc.

1.  Reduction of Furnace/Exhaust Gases

After the reduction of SiCl₄, H₂ and SiHCl₃ gas via drying, H₂ and HCl can be reused. H₂ gas would need to be filtered before reuse to remove silicon powder and graphite powder. This guarantees no contaminants, the hydrogen purity, allowing a more stable and efficient hydrogenation and reduction reaction.

Problems	Requirements	Solutions
Dangerous H₂ Gas	Good sealing performance	An automatic backwash system. Removes the need to open the filter. Reduces frequency of replacing the internal parts. Prevents leakage.
Graphite powder/ silicon powder has high hardness and small particle size.	High filtration precision to prevent contamination.	Unique sintered felt metal internals. Ensures filter aperture stability. High filtration precision, up to 0.1 – 0.5 µm.
High Exhaust Temperature	High temperature resistance Removes need for cooling processes. Prevent downstream problems	Feature-Tec heat treatment process can be adopted to avoid cooling the process stream. Prevents energy wastage.

2. Waste Incineration and Removal
One of the problems in polysilicon production technology is the treatment of waste gases and liquids. Traditional spray process incurs high costs, high wastage, and creates a serious environmental problem.Solution:Feature-Tec uses dry separation technology, channeling waste gases and liquids into a combustion chamber to generate SiO₂ powders. Through separation, the dry SiO₂ powders can be recovered, resulting in great economic benefits, while at the same time solving the issue of meeting environmental standards.Technological Benefits:

1. Waste gas/liquid concentration treatment incorporates a short process and requires only simple operation.

2. Recovery of SiO₂ powders produces great economic benefits.

3. Outlet gas meets environmental protection requirements after combustion for release to the environment.