How OCC Pulping System Design Impacts Kraft Liner Board Quality | Leizhan

Kraft Liner Production: Equipment and Process Overview

Kraft linerboard production from recycled fiber requires a carefully integrated stock preparation and paper machine system. The process converts OCC (old corrugated containers) and kraft cuttings into high-strength linerboard suitable for corrugated box manufacturing.

Key Equipment Specifications

A complete kraft liner production line rated at 300-600 TPD includes the following major equipment:

• Hydraulic Pulper: D-type design, 132-500 kW motor, pulping consistency 4-6%, batch time 15-20 minutes
• High-Density Cleaner: 3-4 stage cascade, inlet consistency 3-4%, reject rate below 8%
• Pressure Screen: 0.15-0.35mm slots, 2-stage screening, fiber recovery above 95%
• Double Disc Refiner: 660-910mm discs, 250-900 kW, freeness reduction 8-12 °SR per pass
• Paper Machine: 3200-4800mm wire width, 90-250 gsm, 350-500 m/min design speed

Energy Performance Data

Operating data from kraft liner mills shows the following energy benchmarks:

• Stock preparation power: 80-120 kWh per ton of pulp
• Paper machine drive power: 280-320 kWh per ton of paper
• Steam consumption: 1.6-1.8 tons per ton of paper (closed hood)
• Water usage: 8-12 m3 per ton (closed-loop recycling)

These figures represent a 15-20% reduction compared to older configurations, achieved through optimized rotor designs, heat recovery, and VFD controls.

Maintenance Guidelines

• Daily: Check lubrication levels, inspect doctor blade contact, monitor bearing temperatures (max 70°C)
• Weekly: Inspect wire tension, verify steam trap function, check felt tracking
• Monthly: Calibrate sensors, check gearbox oil, inspect refiner plate gap
• Quarterly: Replace doctor blades, inspect roll bearings, check screen basket wear
• Annual: Dryer cylinder inspection, gearbox overhaul, headbox cleaning

Quality Parameters

• Burst Index: 3.0-4.5 kPa.m2/g
• Ring Crush Test: 1.5-2.5 kN/m
• STFI Compression: 4.0-6.5 kN/m (150 gsm)
• Moisture Content: 7-9% at reel

Contact us for a technical proposal: leizhanzhang@gmail.com | Zhengzhou Leizhan Technology Paper Machinery Co., Ltd.