Flash Tank Flared Inlet Insert for Black Liquor Turbulence Reduction

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Solution Overview

Problem

Conventional flash tanks experience disruption and turbulence when black liquor enters through abrupt transitions, leading to inefficient flashing and energy loss in pulping systems.

Innovation Solution

The introduction of an insert inlet tube assembly with a cylindrical section and a flared section that is gradually offset towards the sidewall, maintaining a substantially uniform cross-sectional area and using wear-resistant materials to minimize turbulence and ensure structural integrity, allowing for smoother flow and reduced pressure release disruptions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If black liquor enters through an abrupt transition from inlet pipe to flash tank, then the结构简单 (structure is simple), but turbulence and disruption occur leading to energy loss

Engineering Contradiction:
Improveinlet structure simplicityVSAvoidenergy loss from turbulence
Core Design Contradiction:
Ease of manufactureVSLoss of energy

Solution Approach 1:

An insert inlet tube is introduced as an intermediary component between the inlet pipe and flash tank chamber. This tube features a gradual flare section that mediates the transition, allowing smooth flow adaptation and eliminating abrupt transitions that cause turbulence. The insert tube acts as a buffer zone that transforms the incoming flow pattern without requiring complete redesign of either the inlet pipe or tank structure.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The insert inlet tube incorporates a curved, flared geometry instead of sharp angles or abrupt transitions. The gradual flare section uses continuous curvature to guide the flow smoothly from the inlet pipe into the flash tank chamber, reducing flow separation and turbulence. This curved transition path maintains kinetic energy and minimizes disruptive eddies.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Stability of the object's composition

If the insert inlet tube flared section is gradually offset towards sidewall, then flow smoothness is improved, but manufacturing precision requirements increase

Engineering Contradiction:
Improveflow stabilityVSAvoidflare section geometry precision
Core Design Contradiction:
Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The flare section geometry is defined by specific parameters including flare angle, offset distance from centerline, and section length. By optimizing these parameters, the design achieves smooth flow transition while maintaining manufacturability. The gradual offset creates a controlled flow direction change that stabilizes the liquid stream without requiring ultra-precise manufacturing tolerances.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If wear-resistant materials are used for insert inlet tube, then structural integrity and durability are improved, but manufacturing complexity and cost increase

Engineering Contradiction:
Improveinlet tube durabilityVSAvoidmaterial selection complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The insert inlet tube is constructed from composite or coated materials that combine structural integrity with wear resistance. This may involve using stainless steel base material with protective coatings, or composite materials that provide both mechanical strength and resistance to chemical degradation from black liquor. The composite approach achieves enhanced durability without requiring entirely new material systems.

Inventive Principle:
Principle #40Composite materials

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 design minimizes turbulence and ensures a smooth, direct flow of black liquor into the flash tank, enhancing the flashing process by maintaining constant velocity and reducing energy loss, thereby improving the efficiency of steam generation and chemical recovery.

Implementation Method 1

The insert inlet tube may include a cylindrical section having a circular cross-section centered on the longitudinal axis, and a flared section between the circular section and the insert outlet, wherein the flared section is gradually offset from the longitudinal axis of the cylindrical section toward a sidewall of the flash tank proximate to the insert outlet

Methodology Applied
Scientific EffectTurbulence reduction through gradual flow transition: Turbulence

Implementation Method 2

Flash tanks are generally used to flash a high pressure fluid liquor stream including steam and condensate

Methodology Applied
Scientific EffectFlash evaporation: Flash Evaporation

Data Source

PatentEP2808441B1Flash tank with flared inlet insert and method for introducing flow into a flash tank
Publication Date: 2021.04.21 ANDRITZ INC
  • EP2808441B1 patent drawingFigure 1
  • EP2808441B1 patent drawingFigure 2
  • EP2808441B1 patent drawingFigure 3

AI summary

A flash tank (10) includes: an interior chamber having a interior surface formed by a sidewall of the flash tank (10); a vapor exhaust port coupled to an upper portion of the chamber; a liquid discharge port coupled to a lower portion of the chamber; an insert inlet tube (34) having an insert outlet (36) and inserted into an inlet port (18) of the chamber, wherein the insert inlet tube (34) extends inward of the sidewall and the insert outlet (36) has an elongated cross-sectional shape oriented substantially parallel to a center vertical axis (24) of the flash tank (10) and substantially perpendicular to a radial line of the flash tank (10), such that the insert outlet (36) is substantially tangential to the sidewall.