Direct Reduction Gas Heating via Electrical Plasma

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Solution Overview

Problem

Existing methods for increasing the inlet temperature and production output in metal oxide direct reduction processes face challenges such as reduced reduction power, increased energy consumption, and limitations due to maximum plant pressure and reformer temperature constraints.

Innovation Solution

The method involves heating at least one precursor gas based on reformer gas using electrical energy to prepare the reduction gas, allowing for increased temperature without introducing oxygen or combustion products, thus avoiding associated disadvantages.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If oxygen is introduced into the gas stream to induce temperature-increasing combustion of reducing constituents, then the inlet temperature increases and production output increases, but the reduction power of the reduction gas decreases and specific energy consumption increases

Engineering Contradiction:

Improveinlet temperatureVSAvoidreduction power

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The patent replaces combustion heating (chemical energy conversion) with electrical heating to raise the inlet temperature. Electrical energy is applied directly to the reduction gas or heating elements in the reduction shaft, eliminating the need to introduce oxygen and combust reducing constituents. This substitution preserves the reduction power of the gas while achieving the desired temperature increase.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the heating method from combustion-based thermal heating to electrical heating. By applying electrical energy directly to the system, the temperature parameter can be increased without altering the chemical composition of the reduction gas. This parameter change allows independent control of temperature while maintaining the gas's reducing properties.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If additional natural gas is burned with oxygen to increase temperature, then the reduction gas rate increases, but soot formation occurs and gas flows become unfavorable

Engineering Contradiction:

Improvereduction gas rateVSAvoidsoot formation

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent replaces combustion heating with electrical heating, eliminating the source of soot formation. By using electrical energy instead of burning natural gas, the system achieves temperature increase and improved gas flow rates without generating soot or other combustion byproducts that would contaminate the reduction gas stream.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent converts the harmful effect of combustion (soot formation) into a beneficial approach by using electrical heating. Instead of burning fuel to heat the gas (which creates soot), the system uses electrical energy directly, turning a harmful process into a clean and efficient heating method that improves gas flow and eliminates contamination.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Productivity

If the inlet temperature is increased to achieve desired plant output, then production output increases, but the reformer temperature limits are approached

Engineering Contradiction:

Improveproduction outputVSAvoidreformer temperature

Core Design Contradiction:

ProductivityVSTemperature

Solution Approach 1:

The patent segments the heating function into two separate zones: the reformer maintains its optimal temperature for gas production, while a separate electrical heating system raises the inlet temperature to the reduction shaft. This segmentation allows the reformer to operate at moderate temperatures without compromising production output, as the additional heating is applied downstream where it is most effective.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces electrical heating as an intermediary between the reformer and the reduction shaft. This intermediary heating system bridges the temperature gap without requiring the reformer itself to operate at excessively high temperatures. The electrical heating element acts as a mediator that transfers energy to the reduction gas independently of the reformer's thermal state.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 approach enables a significant increase in direct reduction plant output without consuming reducing gas components for temperature increase, thereby maintaining reduction potential and improving safety by avoiding explosive mixtures.

Implementation Method 1

preparation of the reduction gas involves heating at least one precursor gas based on reformer gas, and optionally additionally also one or more further precursor gases, by means of electrical energy

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Data Source

PatentUS12209293B2Process and apparatus for direct reduction with electrically heated-up reduction gas

Publication Date: 2025.01.28 PRIMETALS TECH AUSTRIA GMBH

AI summary

A method of direct reduction of metal oxides that includes catalytic reforming of hydrocarbonaceous gas in a reformer to obtain reformer gas, obtaining at least one precursor gas based on the reformer gas, preparing a reduction gas by heating the at least one precursor gas by means of electrical energy, at least a portion of the electrical energy being introduced by means of plasma.