The Challenge: Navigating Waste Complexity and Energy Costs

As a large-scale paper mill with an annual capacity exceeding 1 million tons, the facility produces high-quality paper primarily from recycled OCC (Old Corrugated Containers), alongside other types of recovered paper, generating hundreds of tons of complex waste daily. 

This includes light rejects and pulper ropes—mixtures of soft plastics, rubber, hard plastics, paper fibers, and metal wires—along with other residues, all notoriously difficult to recycle.

Previously, the mill relied on third-party disposal, incurring fees of roughly $4–$7 per ton, resulting in significant annual costs. 

This approach strained budgets and risked secondary pollution, falling short of sustainable goals. With energy costs—primarily from coal-dependent cogeneration plants—accounting for 20-30% of operating expenses, the mill urgently needed a solution to manage waste and reduce fossil fuel reliance.

Harden's Solution: Dual-Stream RDF Preparation System

Harden's team analyzed the mill's waste streams and energy needs, identifying a twofold opportunity: manage internal residues while leveraging nearby industrial waste resources. 

The result was a tailored, dual-stream RDF preparation system that transforms both mill-generated and external industrial waste into high-value fuel, slashing coal use and carbon emissions.

● Stream A: Paper Mill Waste RDF Preparation

Targeting light rejects, pulper ropes, and other residues, Harden deployed a robust process combining dual-shaft coarse shredding, air separation, magnetic separation, and dual-shaft fine shredding. 

Low-speed, high-torque shredders efficiently tear through irregular waste without clogging, while air separation leverages density differences to isolate light and heavy fractions.

Magnetic separation removes ferrous metals, and fine shredding ensures 99.5% of output meets ≤100 mm size requirements. The result is high-calorific RDF with a 95% impurity removal rate, achieving a capacity of 30 tons per hour.

● Stream B: Industrial Waste RDF Preparation

For external industrial waste—textile waste, leather trimmings, and more—Harden engineered a process with dual-shaft coarse shredding, air separation, magnetic separation, and single-shaft fine shredding. 

Precision screening separates incombustibles and impurities, producing RDF with particle sizes ≤80 mm at 20 tons per hour. This high-quality fuel powers the mill’s cogeneration boilers, maximizing energy recovery.

Impact: From Burden to Breakthrough

“Complex waste used to be a headache—traditional equipment couldn't meet our boilers' strict fuel specs,” said the mill's manager. 

“Harden's RDF system, with its efficient shredding and precise separation, has transformed our waste management. 

The RDF fuel integrates seamlessly into our cogeneration system, producing high-temperature steam and clean electricity, aligning with our low-carbon vision.”

Since its inception in 2023 and with full operation expected by 2025, the system is projected to process 250,000–300,000 tons of waste annually, save 100,000 tons of standard coal, generate 167 million kWh of electricity, and supply 1.166 million tons of steam. 

Carbon emissions are expected to be cut by 260,000 tons yearly, supporting global decarbonization goals. By reducing fossil fuel dependency and disposal costs, the mill is expected to enhance profitability while advancing sustainability.

Harden's Vision: Pioneering Circular Solutions

With over 15 years of experience in solid waste processing and 1,500+ global projects, Harden Machinery turns waste challenges into energy opportunities. 

Looking ahead, Harden will continue advancing DWS systems and single-shaft fine shredding technology to deliver efficient, low-carbon waste processing solutions for enterprises. This Anhui project showcases Harden's role not just as an equipment provider, but as a catalyst for circular economies.