Paper Drying Plant Steam Separation for Stable Heat Recovery

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Solution Overview

Problem

Existing paper drying systems face issues with low-quality steam due to condensate contamination, leading to unstable steam supply and decreased desiccating capacity, and require complex pump systems for energy recovery.

Innovation Solution

A simplified drying plant design with a single pump system, incorporating a first and second separating tank, a heat exchanger, and an adjustment system to produce high-pressure, high-temperature steam by separating condensate from steam, and controlling steam temperature and pressure through pump rotation speed and bypass valve adjustments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If condensate is separated from steam using multiple tanks and pumps for energy recovery, then energy recovery efficiency is improved, but device complexity increases

Engineering Contradiction:
Improveenergy recovery efficiencyVSAvoidpump system complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent combines the functions of multiple separating tanks and pumps into a single separating tank system. The first separating tank separates steam from condensate, and the second separating tank further separates steam from any remaining liquid droplets, eliminating the need for multiple pumps while achieving effective condensate removal and energy recovery

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent extracts and removes condensate from the steam flow through gravitational separation in the first and second separating tanks, allowing clean steam to be directed to the drying roll while condensate is discharged separately, thus improving energy recovery without requiring complex pumping systems

Inventive Principle:
Principle #2Taking out (Extraction)

2Loss of energy

If steam is produced from condensate in existing systems, then energy recovery occurs, but steam quality deteriorates due to condensate contamination

Engineering Contradiction:
Improveenergy recoveryVSAvoidsteam quality
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The patent converts the harmful effect of condensate contamination into a benefit by using gravitational separation in the first and second separating tanks to remove liquid droplets from the steam flow. This allows the system to recover energy from condensate while producing high-quality steam suitable for drying applications

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

Solution Approach 2:

The patent segments the steam-condensate mixture separation into two stages: the first separating tank performs initial separation, and the second separating tank performs final separation before steam is directed to the drying roll. This multi-stage segmentation ensures high steam quality while maintaining energy recovery

Inventive Principle:
Principle #1Segmentation

3Measurement precision

If pump rotation speed is adjusted to control steam production, then steam temperature and pressure control is improved, but system complexity increases

Engineering Contradiction:
Improvesteam temperature and pressure controlVSAvoidadjustment system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent employs dynamic control of the pump rotation speed to adjust the amount of condensate introduced into the heat exchanger, thereby controlling steam temperature and pressure in real-time. This dynamic adjustment mechanism provides precise control without requiring complex additional systems

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements a control system that monitors steam temperature and pressure and adjusts the pump rotation speed accordingly. This feedback mechanism ensures stable steam parameters while maintaining simple system architecture through automated control

Inventive Principle:
Principle #23Feedback

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 achieves high-quality steam production with stable pressure and temperature control, reducing complexity and enhancing energy recovery efficiency.

Implementation Method 1

a heat exchanger (104) which is placed into fluid communication with said first separating tank through a first part of a conduit (103) which connects said first separating tank with said heat exchanger

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 2

the pump (102) arranged along the said first part of conduit, the pump being therefore interposed between said heat exchanger and the first tank and with the said pump configured to push condensate contained into said tank towards the heat exchanger

Methodology Applied
Scientific EffectPhase change: Phase Change

Implementation Method 3

a first separating tank (101) configured to separate the steam from the condensate and placed into fluid communication with the said drying roll in such a way as to receive the fluid coming from said drying roll and separate steam from condensate

Methodology Applied
Scientific EffectGravitational separation: Gravitation

Implementation Method 4

a pump (102) arranged along the said first part of conduit, the pump being therefore interposed between said heat exchanger and the first tank and with the said pump configured to push condensate contained into said tank towards the heat exchanger

Methodology Applied
Scientific EffectPumping: Pump

Implementation Method 5

at least one drying roll (112) fed by steam in such a way as to heat up and on which the paper material to be dried is arranged in use

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 6

the roll is heated since it contains inside a steam passage and, in this way, the heated tape is desiccated since its water content evaporates

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 7

a hood (114) arranged in such a way as to wrap, at least partially, the said drying roll, said hood being configured in such a way as to send onto the said drying roll a drying airflow which hits the said drying roll

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP4729690A2Process and plant for drying paper
Publication Date: 2026.04.22 MEVAS SRL
  • EP4729690A2 patent drawingFigure 1
  • EP4729690A2 patent drawingFigure 2
  • EP4729690A2 patent drawingFigure 3

AI summary

The present invention relates to a drying plant for desiccating paper material, preferably in the form of a tape, the said drying plant comprising: - At least one drying roll (112) fed with steam in such a way as to heat up and on which the paper material to be dried is arranged in use; - At least one hood (114) arranged in such a way as to wrap, at least partially, the said drying roll, the said hood being configured in such a way as to send onto the said drying roll a drying airflow which hits the said drying roll and being further configured to suck in the damp drying flow going up in use from the paper material under drying positioned on the said drying roll; - At least one first separating tank (101) configured to separate the steam from the condensate and placed into fluid communication with the said drying roll in such a way as to receive the fluid coming from the said drying roll and separate steam from condensate; - and wherein a heat exchanger (104) is comprised; - said heat exchanger being placed into fluid communication with said first separating tank through a first part of a conduit (103) which connects said first separating tank with said heat exchanger; - and wherein a pump (102) arranged along the said first part of conduit is comprised, the pump being therefore interposed between said heat exchanger and the first tank and with the said pump configured to push the condensate contained into said tank towards the heat exchanger; - Characterized by the fact of comprising a second tank (108), said second tank being a second separating tank configured to separate steam from condensate and placed into fluid communication with the said heat exchanger through a second part of a conduit (107), said second part of conduit being without pump, the said pump arranged in the first part being configured in such a way as to push the condensate coming from the first separating tank into the heat exchanger (104) and contextually push the consequent fluid obtained from said heat exchanger towards the second separating tank (108), the said second tank being connected to a third part of a conduit (109) configured to send the steam, separated from the condensate, in outlet from said second separating tank, said third part of conduit connecting to the said drying roll (112) in such a way that the drying roll can receive the obtained steam and coming from said second separating tank and wherein, further, the said second separating tank provides an outlet for discharging condensate.