Rotary Tube Furnaces and Calciners

Rotary Tube Furnace

Photo - Rotary Calciner with Cooling System

Harper International Rotary Calciners

Harper rotary tube furnaces and rotary calciners are designed for continuous processing of granular, powder, or particulate aggregates under controlled atmosphere environments at temperatures up to 2400°C.

Rotary furnace systems may be electrically heated or gas-, oil- or dual-fuel fired. The tumbling action of the product within the rotary tube results in high degrees of temperature uniformity and gas-solid contact, resulting in a more homogenous product, reduced processing times and increased production rates. No carrier media is required, so energy is not expended in heating carrier loads. Recuperation further enhances energy efficiency in fossil fuel-fired rotary furnaces. Harper rotary tube furnaces and rotary calciners offer exceptional versatility, reliability and energy efficiency.

Rotary Calciners Specifications

Capabilities
• Temperatures to 2400°C
• Electrically heated or gas-fired
• Controlled atmospheres including
  flammables
• Defined residence times
• Control of exothermic reactions
• Off-gas handing systems
• Testing and prototyping facilities
• Process modeling and scale up
• Complete systems and turnkey
  installation

Features
• Many patented features
• Energy saving design
• Multiple temperature control zones
• Exclusive rotary seal design
• Automatic lubrication
• Feed level detection
• Process gas circulating and
  conditioning systems

Typical Applications
• Calcination
• Reduction
• Controlled oxidation
• Carburization
• Solid-solid reaction
• Purification
• Research and development
• Waste remediation

Materials Processed
• Phosphors
• Titanates
• Zinc oxide
• Quartz
• Ferrites
• Molybdenum
• Cobalt
• Tungsten
• Tungsten carbide
• Catalysts
• Activated carbon
• Inorganic chemicals
• Metals and metal oxides
• Rare earths
• Uranium compounds

Major Advances in Harper Rotary Tube Furnace Systems

High Temperature
Graphite Rotary Tube Furnace System

The Harper graphite rotary tube furnace system is the most advanced available today. The absence of moving parts in the tube support system provides a simple, reliable, robust design that enhances scalability. Applications include carburizing hard metal powders, carbon and graphite powder processing and synthesis of non-oxide ceramic powders.

Multi-Zone Graphite
Rotary Tube Furnace (patented)

Photo - Ultra High Temperature graphite rotary with atmospheric control

Photo - Schematic of Graphite Rotary System

Riffle Flight (patented)	Riffle Flights Installation

Riffle Flights

Riffle flights provide axial mixing for processing at a fixed average composition and are excellent for moderating exothermic reactions or continuous in-line mixing.

Ideal Plug flow

EHTA System

Minimized Residence Time Distribution

Helical flights convey material without back-mixing and are utilized for processes that require narrow residence time distributions.

Enhanced Heat Transfer

Tubes penetrate the material process bed. Mating refractory shapes channel heating or cooling gases in an overall countercurrent stream for high heat transfer. Ideal for temperature-sensitive materials.

Cross Flow System (patented)

Superior Gas-Solid Reaction

Coarse, free-flowing material can be heated and reacted with through-flowing gas. Gas flows locally to the solid material path while globally flowing counter-current to material flow, providing superior gas-solid contact.

Sealing System (patent pending)

Photo - Sealing technology for control of atmosphere and gases

Advanced Sealing System

Our patented rotary reactor sealing system provides optimal rotary tube furnace atmosphere integrity with minimal gas consumption.

Rotary tube furnace

Photo - Pilot Scale Rotary System / Morphology Development

Feasibility, Process Analysis and Advanced Design Studies

Harper's Technology Center and interdisciplinary team of chemical and mechanical engineers and materials scientists are available to explore, develop and scale up exciting new rotary tube furnace processes and applications.

Our technology group possesses expertise in areas as diverse as carbon and graphite processing, inorganic chemicals, non-oxide ceramics, nano-composites and other advanced materials. Advanced design and analysis incorporates solids flow, heat transfer and computational fluid flow modeling enabling concurrent
engineering, reduced project lead time
and process optimization.

Harper Technology Center

Testing at Harper

Rotary tube furnace available for testing your product at Harper's Piloting/Testing facility.

Turnkey rotary tube reactor

Photo - Highly engineered Turnkey Systems

Complete Systems

This turnkey rotary tube reactor system has automated material feed and discharge, PLC-based executive control instrumentation and complete off gas handling.

The design of the rotary tube system can also incorporate process controls, skid mounting, turnkey installation and complete field commissioning. Field service can incorporate control instrumentation integration and programming as well as process engineering optimization and support.

Cascade rotary tube furnace

Photo - Rotary systems to streamline processes

Versatility and Customization

Cascade rotary tube furnace system capable of multi-stage thermal processing at different temperatures and atmospheres without exposure to ambient conditions or manual material handling.