Corrugated Paper Making Line: High-Strength Medium and Testliner Production

Corrugated Paper Making Line: High-Strength Medium and Testliner Production

Corrugated medium and testliner are the structural components of corrugated boxes, accounting for over 70% of global packaging paper production. A modern corrugated paper making line processes recycled fiber (OCC — old corrugated containers) through robust stock preparation, high-consistency forming, and efficient drying to produce fluting medium (90–150 gsm) and testliner (110–200 gsm) at 300–800 TPD.

The distinguishing feature of corrugated paper production is its tolerance for lower-quality fiber sources. The stock preparation system must handle high contaminant loads including staples, plastics, hot melts, and wet-strength additives commonly found in post-consumer OCC. Equipment selection emphasizes ruggedness, ease of maintenance, and contamination removal efficiency over fine fiber development.

Stock Preparation for OCC Recycling

• Drum Pulper: Capacity 400–800 TPD, operating consistency 15–18% for gentle defibering with minimal contaminant breakdown. Continuous operation with 15–25 minute retention time for complete fiberization. Motor power 400–900 kW.
• High-Density Cleaner: 4–6 inch diameter, feed consistency 3–4%, pressure drop 140–180 kPa. Removes heavy contaminants (stones, metal, glass) with 95%+ efficiency. Multi-stage cascade configuration minimizes fiber loss.
• Coarse Pressure Screen: Basket with 2.0–3.0 mm holes, consistency 3–4%, reject rate 15–25%. Primary function is removing coarse plastics and undisintegrated fiber bundles.
• Fine Pressure Screen: Basket with 0.25–0.35 mm slots, consistency 2–2.5%. Remaining contaminant removal including stickies and hot melts. Two-stage cascade with forward flow for minimal reject loss.
• Low Consistency Refiner: Disc diameter 910 mm, motor 500–900 kW, specific edge load 1.0–2.0 J/m. Focus on fiber cutting to improve drainage while maintaining adequate ring crush and CMT values.

Energy and Operating Cost Analysis

Corrugated paper production using 100% OCC is significantly less energy-intensive than virgin fiber grades. Total electrical consumption averages 320–380 kWh per ton, with the breakdown: pulping 15–20 kWh/t, screening and cleaning 25–35 kWh/t, refining 60–90 kWh/t (lower than kraft due to already-refined recycled fiber), and paper machine 220–240 kWh/t. Steam consumption is 1.6–1.9 tons per ton of paper.

Key cost drivers include refining energy (adjustable based on strength targets), drying steam (optimize through press section dewatering — every 1% dryness increase at the press exit saves 4% in dryer steam), and waste handling from the high-contaminant raw material stream. Mills processing low-quality OCC typically generate 5–8% rejects by weight, requiring adequate landfill or incineration capacity.

Maintenance Practices for High-Contaminant Operations

• Drum pulper screening plates: Inspect weekly — the extraction zone plates experience aggressive wear from tramp metal. Replace plate sections when hole diameter increases beyond 20% of nominal. Stock lubrication with shower water extends plate life.
• High-density cleaner cones: Lower cone sections wear from abrasive contaminants. Rotate or replace lower cones every 6 months. Check apex opening weekly for plugging from oversized debris.
• Pressure screen rotors and baskets: Rotor foils wear fastest on the coarse screen. Inspect monthly — excessive clearance (>1 mm beyond nominal) reduces screening efficiency. Basket slot monitoring every 2 weeks.
• Reject handling system: Conveyors and compactors for screen and cleaner rejects require daily inspection. Hydraulic oil leaks from compactors are a common fire hazard in OCC mills — maintain strict housekeeping protocols.

Complete Corrugated Paper Line Supply

Leizhan Technology supplies full corrugated paper making lines including pulping, screening, cleaning, refining, approach flow, paper machine, and winder. All equipment is engineered for the demanding conditions of 100% OCC recycling with proven field performance.

Contact our technical team at leizhanzhang@gmail.com for a customized corrugated paper line configuration. Equipment details available at www.pulprefining.com.