Vertical Rotary Furnace Heating Element Positioning

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Solution Overview

Problem

Existing rotary furnaces for pyrolysis and roasting of biomass face inefficiencies in heat transfer, leading to significant energy loss and increased costs due to excessive size and energy consumption, as well as the risk of exothermic reactions at high temperatures.

Innovation Solution

A rotary furnace design incorporating a stationary, longitudinally positioned heating element inside the tube, combined with a deflector panel to direct radiation only towards the biomass, ensuring efficient heat transfer without overheating the furnace walls and minimizing exothermic reactions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the length of the rotary furnace is increased to increase heat transfer surface area, then heat transfer efficiency is improved, but investment cost and energy consumption increase

Engineering Contradiction:

Improveheat transfer efficiencyVSAvoidenergy consumption

Core Design Contradiction:

Use of energy by moving objectVSLoss of energy

Solution Approach 1:

The patent transitions from a conventional horizontal rotary furnace to a vertical rotary furnace configuration. This dimensional change allows the heating element to be positioned concentrically within the rotary tube, creating a compact heat transfer geometry that achieves efficient heat transfer without requiring excessive furnace length, thereby reducing both investment cost and energy consumption.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The heating element is positioned to be above the feedstock when the furnace rotates, ensuring that heat is applied to the biomass before it reaches temperatures that would trigger exothermic reactions. This preliminary heating action prevents runaway reactions while maintaining efficient heat transfer.

Inventive Principle:

Principle #10Preliminary action

2Productivity

If high temperatures are used to accelerate heat treatment, then treatment speed is improved, but exothermic reactions are triggered causing mass and energy loss

Engineering Contradiction:

Improvetreatment speedVSAvoidmass loss

Core Design Contradiction:

ProductivityVSLoss of substance

Solution Approach 1:

The heating element is positioned above the feedstock in the vertical rotary furnace, applying heat preliminarily as the biomass rotates through the heating zone. This controlled preliminary heating accelerates the treatment process while maintaining temperatures below the threshold for exothermic reactions, preventing mass and energy loss.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The heating is applied locally and controllably through the vertically positioned heating element, allowing different zones of the furnace to maintain different temperature profiles. This enables efficient heat treatment in the heating zone while preventing overheating in other zones, thus avoiding exothermic reactions.

Inventive Principle:

Principle #3Local quality

3Use of energy by moving object

If heating element emits radiation in all directions, then heat coverage is improved, but energy loss increases and furnace walls are overheated

Engineering Contradiction:

Improveheat coverageVSAvoidenergy loss

Core Design Contradiction:

Use of energy by moving objectVSLoss of energy

Solution Approach 1:

The heating element is positioned concentrically within the rotary tube in a vertical configuration, creating a localized heating zone that directs radiation primarily toward the feedstock bed. This positioning ensures that heat is concentrated where needed rather than being wasted on furnace walls, improving energy efficiency while maintaining adequate heat coverage.

Inventive Principle:

Principle #3Local quality

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This configuration enhances heat transfer efficiency, reduces equipment size and energy consumption, and prevents exothermic reactions, resulting in faster and more cost-effective biomass treatment while maintaining temperatures below critical thresholds.

Implementation Method 1

a heating element that is positioned to be above the feedstock when the furnace rotates

Methodology Applied

Scientific EffectThermal radiation: Thermal Radiation

Implementation Method 2

at least one deflector panel that surrounds the heating element at the side that is opposite to the feedstock

Methodology Applied

Scientific EffectRadiation reflection: Reflection

Implementation Method 3

The transfers by conduction are proportional to the contact surface, to the temperature difference between the feedstock and the wall, and to a coefficient for heat transfer from the wall to the feedstock

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS9091480B2Rotary furnace for radiative heat treatment of solids

Publication Date: 2015.07.28 IFP ENERGIES NOUVELLES

AI summary

A rotary furnace (1) for the heat treatment of solids includes at least one rotary tube into which the solids are introduced and a first heater outside of the rotary tube that makes it possible to conduct a portion of the heat treatment in the absence of oxygen. A second heater for heating feedstock to improve heat treatment is formed by a second heating element (4, 4′, 4″) positioned above the feedstock when the furnace rotates and at least one deflector panel that surrounds the heating element (4, 4′, 4″) is provided on the side opposite to the feedstock (2) and arranged inside of the rotary tube. The rotary furnace is used to roast solid biomass.