I. The "Green Paradox" of PV Manufacturing

Photovoltaic power generation, as a core carbon neutrality technology, achieved a record-breaking 346GW of global installations in 2023. However, behind this "green energy" industry chain lies an awkward reality: the high pollution risks in upstream polysilicon production have become the biggest constraint on the industry's sustainable development.

In the Siemens and modified Siemens processes, the reaction between trichlorosilane (SiHCl?) and hydrogen to produce silicon generates substantial chlorine-containing waste gases, primarily including hydrogen chloride (HCl), chlorine gas (Cl?), and silicon tetrachloride (SiCl?).

• Environmental Impact: Chlorine gas forms hydrochloric acid mist upon contact with water vapor, causing acid rain; silicon tetrachloride hydrolysis produces silicic acid and hydrochloric acid, severely polluting soil and groundwater with impact radius extending several kilometers
• Health Threats: Workers exposed long-term to chlorine-containing environments show respiratory disease rates 40% higher than conventional manufacturing; surrounding residents experience significantly increased asthma and skin allergy cases
• Brand and Capital Risks: ESG rating agencies have incorporated upstream manufacturing pollution into PV enterprise assessments, with the contradiction between "green energy" labels and "high-pollution manufacturing" affecting international capital investment decisions

II. Four-Dimensional Integrated Treatment Strategy

1. Process Innovation: Cutting the Pollution Chain at Source

Leading enterprises have introduced closed-loop circulation technology, converting SiCl? back to SiHCl? through hydrogenation reactions, achieving recovery rates above 95%. GCL Technology's practice demonstrates that Fluidized Bed Reactor (FBR) methods can reduce chlorine consumption by over 30% compared to traditional processes, cutting waste gas generation at the source.

More forward-looking approaches explore chlorine-free process routes. While silane methods present higher technical difficulty, they can fundamentally avoid chlorine-containing waste gas generation, representing the ultimate direction of industry technological evolution.

2. End-of-Pipe Treatment: Precise and Efficient Purification Systems

Chaori Environmental's low-temperature catalytic oxidation technology has pioneered breakthrough of traditional high-temperature treatment energy consumption bottlenecks. Effectively decomposing Cl? and HCl below 200℃, energy consumption is reduced by 40% compared to traditional methods, providing economically viable solutions for SMEs.

Plasma-assisted treatment technology, while still in laboratory stages, shows enormous potential with 98% treatment efficiency. Active species generated by high-voltage discharge can rapidly decompose chlorine-containing compounds, promising to become mainstream next-generation waste gas treatment technology.

3. Policy Driving: Standard Upgrades Force Technological Progress

China's "Polysilicon Industry Standard Conditions" 2023 revision tightened Cl? emission standards to ≤15mg/m³, a 75% improvement over previous standards. This "forcing-type" regulation accelerates industry consolidation, with technologically backward enterprises facing elimination risks.

4. Industrial Collaboration: Building Waste Gas-Resource Circular Ecosystem

PV module manufacturers collaborate with chemical companies to use recovered SiCl? for optical fiber preform production, with LONGi-Hengtong cooperation proving commercial viability. Park-based treatment shows clear advantages in Northwest regions, achieving centralized treatment, economies of scale, and maximum resource utilization.

III. Intelligent Empowerment: Data-Driven Precision Control

AI monitoring systems analyze real-time waste gas composition and concentration changes, dynamically adjusting alkaline solution dosing. One leading enterprise reported 25% reduction in chemical costs post-application. More importantly, AI systems predict equipment failures and process fluctuations, transforming passive response to proactive prevention.

Digital twin factory technology demonstrates enormous value in Tongwei's pilot project. By establishing virtual simulation models, waste gas treatment processes can be optimized without affecting production, predicting equipment failure rates and providing scientific basis for refined management.

V. Ultimate Vision: Chlorine Element Full-Cycle Zero-Emission Future

The industry's ultimate goal is achieving complete "waste gas-raw material-product" closed-loop circulation, enabling infinite chlorine element cycling within systems for true zero emissions. By 2030, leading enterprises are expected to achieve this goal.

More revolutionary is green electricity hydrogen production technology application. Using green hydrogen from PV power generation to replace traditional HCl in silane synthesis shows experimental conversion rates exceeding 80%, achieving perfect "clean energy manufacturing clean energy" closed loop.

Conclusion: The PV industry stands at a historic turning point. Waste gas treatment is no longer simple compliance cost, but comprehensive testing of technological innovation, business model reconstruction, and sustainable development. Enterprises capable of pioneering this transformation will occupy unshakeable advantageous positions in future global competition.