Clinker Feed Conveyor Using Recirculation Gas to Block False Air

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Solution Overview

Problem

The ingress of false air through the raw flour feed in cement clinker production plants is a significant issue, leading to contamination and altering the solid-state chemistry and heat balance, which is exacerbated by incomplete sealing in transport and metering devices.

Innovation Solution

A conveying device with a gas supply for recirculating gas is integrated into the cement clinker production plant, displacing atmospheric air during bulk material transfer and adjusting gas flow based on material flow rate to maintain optimal conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If atmospheric air is used as carrier gas for bulk material transport, then sealing requirements are reduced, but nitrogen contamination increases and carbon dioxide content decreases

Engineering Contradiction:
Improvesealing requirementsVSAvoidnitrogen content
Core Design Contradiction:
Ease of manufactureVSQuantity of substance

Solution Approach 1:

The patent applies the inert atmosphere principle by using recirculating exhaust gas (rich in CO2 and depleted in N2) as the carrier gas instead of atmospheric air. This creates a controlled gas environment that prevents nitrogen contamination while maintaining effective bulk material transport. The recirculating gas acts as an inert medium relative to the chemical processes occurring in the kiln system.

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

Solution Approach 2:

The patent implements parameter changes by systematically adjusting the composition of the carrier gas from atmospheric air (78% N2, 21% O2) to recirculating exhaust gas with controlled CO2 and N2 ratios. By varying the recirculation rate and controlling false air ingress, the gas composition parameters are optimized to achieve both low nitrogen content and effective conveying performance.

Inventive Principle:
Principle #35Parameter changes

2Quantity of substance

If recirculating gas is used to displace atmospheric air, then nitrogen contamination is reduced, but false air ingress becomes more detrimental

Engineering Contradiction:
Improvenitrogen contentVSAvoidfalse air ingress
Core Design Contradiction:
Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary anti-action by proactively preventing false air ingress through optimized sealing arrangements and pressure control measures. Rather than attempting to remove nitrogen after it enters the system, the design preemptively blocks atmospheric air from entering through the bulk material feed system, thereby protecting the recirculating gas composition from contamination.

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The system implements feedback control by monitoring the composition of the recirculating gas and adjusting operational parameters to maintain optimal CO2 concentration and minimize false air ingress. The feedback mechanism ensures that the recirculating gas maintains its low-nitrogen, high-CO2 characteristics throughout continuous operation.

Inventive Principle:
Principle #23Feedback

3Quantity of substance

If sealing is improved to prevent false air ingress, then nitrogen contamination decreases, but device complexity increases

Engineering Contradiction:
Improvenitrogen contentVSAvoidsealing arrangements
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The patent uses the recirculating exhaust gas itself as an intermediary medium that fills the pore volume of the bulk material, displacing atmospheric air without requiring complex mechanical sealing. This gas-phase intermediary approach is simpler than implementing elaborate mechanical seals or pressure barriers, as it uses the process gas to achieve the sealing effect.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system applies pneumatic principles by using pressurized recirculating gas to purge atmospheric air from the bulk material stream. The pneumatic displacement mechanism relies on gas flow dynamics rather than mechanical sealing, reducing device complexity while effectively preventing false air ingress through the porous bulk material.

Inventive Principle:
Principle #29Pneumatics and hydraulics

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

Prevents false air ingress, maintaining the nitrogen-free or low-nitrogen atmosphere necessary for efficient carbon dioxide recirculation and reducing nitrogen contamination, thereby optimizing the carbon dioxide-rich exhaust gas composition.

Implementation Method 1

the conveying device further comprises a gas supply for supplying recirculating gas to the cement clinker production plant... This gas supply displaces any atmospheric air during the transfer of the bulk material to be conveyed into the cement clinker production plant

Methodology Applied
Scientific EffectGas displacement:

Implementation Method 2

a conveying device for transporting bulk material... Transport from the drying and dehydration system is pneumatically operated

Methodology Applied
Scientific EffectPneumatic conveying:

Data Source

PatentEP4430011B1Plant for the production of cement clinker using the oxy-fuel process, method for operating a plant for the production of cement clinker and using recirculation gas from a plant for the production of cement clinker
Publication Date: 2026.01.21 KHD HUMBOLDT WEDAG GMBH
  • EP4430011B1 patent drawingFigure 1

AI summary

The invention relates to a conveyor device (100) for conveying bulk material (10) for a system (20) for producing cement clinker. The system (20) for producing cement clinker is operated using a recirculation method and/or an oxy-fuel combustion method, and the conveyor device (100) has a connection (110) to the system (20) for producing cement clinker, bulk material (10) to be transported being transferred into the system (20) for producing cement clinker in said connection. According to the invention, the connection (110) between the conveyor device (100) and the system (20) for producing cement clinker has a gas feed (120) for supplying the connection (110) with recirculation gas. The aforementioned design allows a separation between atmospheric air and recirculation gas in the system for producing cement clinker.