Polycrystalline silicon (polysilicon) is an important industrial raw material, is different from monocrystalline silicon, a single silicon material, chemically stable at room temperature, with semiconductor properties, is the manufacture of solar panels of the main materials, and is therefore widely used in the photovoltaic industry, to achieve the transformation of solar energy to electrical energy green energy. Higher purity polycrystalline silicon is used in the manufacture of monocrystalline silicon, monocrystalline silicon is further processed into wafers, which are ultimately integrated into chips, becoming the “core” of the modern electronics industry.

Filtration Separation in Polysilicon Production
The main production technologies for polysilicon are the modified Siemens method and the silane method, where the raw materials are mainly silicon powder, hydrogen chloride and hydrogen, etc., which are reacted under certain conditions to generate high-purity gaseous reaction products, and the solid silicon generated by thermal decomposition reaction is deposited on the surface of a high-purity silicon core at high temperatures through the chemical vapor deposition (CVD) process. In the modified Siemens method in the powder transportation unit, cold hydrogenation unit, reduction unit, distillation unit, tail gas recovery unit and silane pyrolysis furnace pyrolysis unit in the silane method, there is a large number of solid particles filtration and separation needs, and the traditional wet de-dusting is difficult to meet the progressively more stringent policies and regulations. In the field of polysilicon manufacturing, the Ministry of Industry and Information Technology in November 20, 2024 released the revised “Photovoltaic Manufacturing Industry Specification Conditions (2024 this)”, the industry to further regulate the production process of power consumption, water consumption, product quality requirements, and gradually guide the photovoltaic enterprises to the development of green industry. [1][2]

Problems of traditional wet de-dusting
⚠️ serious waste of water resources;
⚠️ need to carry out a large number of wastewater treatment or slurry treatment, equipment, personnel and energy costs are high;
⚠️ silica powder raw materials are wasted, the cost is high;
⚠️ silica powder leakage is easy to block the pipeline and heat exchanger, damage to the instrumentation, resulting in unscheduled stops;
⚠️ safety and environmental protection problems are serious, and the risk factor for the treatment of chlorosilanes and trichloroaluminum is high.

Shinkai Filtration guards the stability of polysilicon industry with ease
Due to the poor precision, temperature resistance and mechanical properties of traditional filtration equipment, it is unable to meet the requirements of high-temperature gas-solid separation, which leads to a large number of solid particles in the gas-phase products entering the subsequent section. Gas-phase products after condensation liquefaction, enrichment for distillation separation, and condensate enrichment will produce a large number of slurry (containing silica, chlorosilanes, aluminum trichloride, hydrogen chloride, etc.), slurry treatment is often a huge cost, and if simply landfill disposal, will cause serious pollution, damage to water and soil.

Gas-solid filtration–High-temperature online blowback
For the high-temperature gas-solid separation problem in polysilicon production, Shinkai adopts self-manufactured metal membrane filtration elements to develop high-temperature gas-solid filters, which are used for the complete separation of gas-phase products and solid particles under high-temperature and high-risk environments, and at the same time, can realize the filter regeneration through high-temperature online blowback, which greatly reduces At the same time, it can realize filter element regeneration through high temperature on-line backblowing, which greatly reduces the processing capacity of subsequent processes, reduces the waste of reaction products and water resources, effectively eliminates the pressure on safety and environmental protection, and ensures stable product quality.

Liquid-solid filtration–Dry condensate filtration In response to the traditional filtration problems such as large water consumption, difficult recovery of silica powder, and easy damage and corrosion of piping equipment, Xiongkai has self-developed dry condensate filters, which also use metal membrane filtration elements, and have the following advantages in the subsequent liquid-solid filtration process of polycrystalline silicon:
✔ Maximize the reduction of water consumption;
✔ 100% interception of silicon powder larger than 0.1 μm, no loss of raw materials;
✔ High temperature resistance (900 ℃);
✔ High strength (positive pressure resistance of 50 bar);
✔ Strong corrosion resistance, solvent resistance, acid and alkali resistance;
✔ Reduced environmental protection and safety risks;
✔ Patented full-automatic backwash regeneration process;
✔ Maximum use of the element can be up to 10 years, no need for frequent replacement of spare parts;
✔ Enclosed space, full-automatic ✔ Confined space, fully automatic operation, reduce personnel workload;
✔ Filtering device is reasonable in design, simple in installation and convenient in operation.

Shinkai’s high-efficiency filtration systems have been successfully applied to many polysilicon enterprises. In a 10,000-ton annual production capacity of electronic-grade high-purity polysilicon project of a leading polysilicon enterprise, our professional filtration solution not only fully complies with the stringent environmental protection and safety standards, but also significantly improves the production efficiency, and achieves considerable cost optimization for the customer.