Ultrasonic Smelt Dissolving to Mitigate Runaway Explosions

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Solution Overview

Problem

Conventional dissolving tanks in chemical pulping processes face safety risks from runaway smelt explosions due to heavy smelt flows and scaling issues on agitators, which are not adequately addressed by existing systems, leading to potential explosions and production interruptions.

Innovation Solution

A system utilizing ultrasonic transducers emitting waves above 20 KHz to destabilize the vapor layer around smelt droplets, combined with sensors and a data processor to adjust ultrasonic wave intensity and agitation rates, mitigating explosion risks and reducing scaling on agitators.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If shatter jets are used to disrupt smelt flow, then explosion intensity is reduced, but device complexity and operational safety are compromised due to inability to remotely adjust discharge rate

Engineering Contradiction:
Improveexplosion intensityVSAvoidremote adjustability
Core Design Contradiction:
Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The patent replaces the mechanical shatter jet system with an ultrasonic vibration system. The ultrasonic transducer generates high-frequency vibrations that disrupt smelt flow and prevent explosion without requiring mechanical nozzles or fluid discharge mechanisms that cannot be remotely adjusted. This substitution enables remote control capability while maintaining the beneficial effect of reduced explosion intensity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the operating parameters by using ultrasonic frequency vibrations instead of mechanical fluid discharge. The ultrasonic transducer operates at specific frequencies and amplitudes that can be remotely controlled and adjusted, providing parameter flexibility that was unavailable in the mechanical shatter jet system.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If smelt flow rate increases, then productivity is improved, but safety risk increases due to potential runaway explosions

Engineering Contradiction:
Improvesmelt flow rateVSAvoidsafety risk
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The ultrasonic transducer applies preliminary action by continuously vibrating the smelt flow before it can accumulate to dangerous levels. This preventive vibration disrupts the smelt flow pattern and prevents the conditions necessary for runaway explosions, allowing higher flow rates to be processed safely.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system incorporates sensors that monitor smelt flow conditions and provide feedback to the control system. When abnormal conditions are detected, the control system can adjust the ultrasonic transducer operation to prevent explosion, enabling safe operation at higher productivity levels through real-time monitoring and adjustment.

Inventive Principle:
Principle #23Feedback

3Device complexity

If conventional dissolving tanks are used, then device complexity is minimized, but harmful factors increase due to scaling on agitators and explosion risks

Engineering Contradiction:
Improvesystem simplicityVSAvoidscaling and explosions
Core Design Contradiction:
Device complexityVSObject-generated harmful factors

Solution Approach 1:

The patent merges the ultrasonic transducer with the existing dissolving tank and agitator system. The ultrasonic vibration function is integrated into the tank operation, combining the original mechanical agitation with ultrasonic disruption to simultaneously address scaling and explosion risks without requiring a completely new system.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent substitutes ultrasonic vibration for part of the mechanical agitation function. The ultrasonic transducer performs the smelt disruption function that previously required complex mechanical shatter jets, reducing device complexity while eliminating the associated safety and operational problems.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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

The system effectively accelerates smelt dissolution, reduces the need for disrupting fluids, enhances safety by preventing explosions, and decreases energy consumption by minimizing agitator energy use and scaling, thereby improving operational reliability and efficiency.

Implementation Method 1

an ultrasonic transducer configured to emit ultrasonic waves above 20 kilohertz

Methodology Applied
Scientific EffectUltrasonic vibration: Ultrasonic Vibration

Implementation Method 2

emit ultrasonic waves above 20 kilohertz in the dissolving tank

Methodology Applied
Scientific EffectAcoustic cavitation: Acoustic Cavitation

Data Source

PatentEP3656914B1Ultrasonic smelt dissolving and shattering system
Publication Date: 2025.09.03 ANDRITZ INC
  • EP3656914B1 patent drawingFigure 1
  • EP3656914B1 patent drawingFigure 2

AI summary

The problem of runaway smelt explosions due to a sudden influx of smelt into a dissolving tank is mitigated by a system comprising a dissolving tank (135); a spout (105) adjacent to the dissolving tank (135), wherein the spout is configured to convey a volume of smelt (110) into the dissolving tank (135); an agitator (140) disposed in the dissolving tank (135), wherein the agitator (140) is configured to mix the volume of smelt (110) into a dissolving liquid (130) in the dissolving tank (135); and an ultrasonic transducer (150) configured to emit ultrasonic waves (153) within the dissolving tank (135) at a frequency above 20 kilohertz. A system comprising the ultrasonic transducer may further comprise sensors and a data processor configured to regulate the properties of the ultrasonic waves in response to process conditions affecting the smelt flow.