Fiber Web Drying Section With Exhaust Steam Recovery Reuse
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Solution Overview
Problem
Existing fiber web production lines face inefficiencies in recovering and reusing exhaust steam from superheated steam drying (SSD) units, leading to energy waste and increased costs.
Innovation Solution
A drying section incorporating cylinder drying and SSD units with an exhaust steam recovery system that cleans, pressurizes, and desuperheats steam for reuse as a heating medium in cylinder drying units, utilizing a steam cleaning unit, superheated steam generator, and desuperheating unit to optimize steam utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If exhaust steam from SSD unit is discharged without recovery, then the drying process can be maintained, but energy is wasted and operating costs increase
Solution Approach 1:
The patent implements a steam recovery system that captures exhaust steam from the SSD unit and redirects it to the cylinder drying group. The system includes a steam cleaner to purify the exhaust steam, a steam generator to adjust steam parameters, and piping to deliver the recovered steam to the drying cylinders, thereby converting waste steam into a useful resource.
Solution Approach 2:
The recovered exhaust steam from the SSD unit is universally applied to multiple drying cylinders in the cylinder drying group. The steam recovery system serves multiple functions: it purifies steam, adjusts temperature and pressure, and distributes steam to multiple heating points, making the recovered steam a multi-functional resource throughout the drying section.
2Productivity
If steam is recovered and reused in cylinder drying group, then energy efficiency increases, but the system complexity and equipment requirements increase
Solution Approach 1:
The patent introduces a steam cleaner as an intermediary device between the SSD unit and the cylinder drying group. This steam cleaner purifies the exhaust steam by removing contaminants before the steam is reused in the drying cylinders, ensuring that the recovered steam maintains adequate quality for effective drying while protecting the drying system from potential damage.
Solution Approach 2:
The steam generator in the recovery system adjusts the physical parameters of the recovered steam, including temperature and pressure, to match the requirements of the cylinder drying group. This parameter adjustment ensures that the reused steam can effectively perform the drying function despite having different characteristics than the original superheated steam.
3Speed
If superheated steam temperature is increased to improve drying speed, then drying efficiency increases, but energy consumption and equipment stress increase
Solution Approach 1:
The steam recovery system creates a continuous cycle where exhaust steam from the SSD unit is continuously captured, cleaned, and fed back to the cylinder drying group. This continuous reuse of steam maintains sustained drying action without requiring continuous generation of new superheated steam, thereby reducing overall energy consumption while maintaining drying effectiveness.
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
Significantly increases energy efficiency by reusing exhaust steam and condensate, reducing the need for additional superheated steam input during the drying process, and minimizing system inefficiencies due to air ingress.
Implementation Method 1
a steam cleaning unit configured to remove contaminants by cleaning and/or by filtration and/or by separation from the SSD unit received exhaust steam
Implementation Method 2
a superheated steam generator configured to heat with at least an electric heater a first part of the recovered steam cleaned in the steam cleaning unit and to generate superheated steam
Implementation Method 3
heat with at least an electric heater a first part of the recovered steam
Implementation Method 4
at least one steam compressing unit configured to compress a second part of the recovered steam cleaned in the steam cleaning unit and to desuperheat the second part of the recovered steam to generate saturated steam
Implementation Method 5
at least one steam compressing unit configured to compress a second part of the recovered steam cleaned in the steam cleaning unit
Implementation Method 6
the groups of drying cylinders comprise two wires, which press the fiber web, one from above and the other one from below, against heated cylinder surfaces
Implementation Method 7
superheated steam drying (SSD) the fiber web to be dried is guided to an SSD unit, in which superheated steam is blown towards the surface of the fiber web as impingement drying
Implementation Method 8
superheated steam is blown towards the surface of the fiber web as impingement drying
Data Source
Figure 1~2
Figure 3A~3B
Figure 4
AI summary
The invention relates to a drying section for drying a fiber web, which drying section (10) comprises at least one cylinder drying unit (11; 13) and at least one superheated steam drying (SSD) unit (12), and a steam system (20) comprising an exhaust steam recovery system (30). The exhaust steam recovery system (30) is configured to receive exhaust steam (Sout) from the SSD unit (12) and comprises a steam cleaning unit (24) configured to remove contaminants by cleaning and/or by filtration and/or by separation from the SSD unit (12) received exhaust steam (Sout). The exhaust steam recovery system (30) comprises a super heated steam generation (279 configured to heat at least with an electric heater a first part (S1) of the recovered steam (S1) cleaned in the steam cleaning unit (24) and at least one steam compressing unit configured to compress a second part (S2) of the recovered steam cleaned in the steam cleaning unit (24) and connected to the at least one cylinder drying unit (11; 13) configured to receive the pressurized second part of the recovered steam cleaned in the steam cleaning unit (24) to be used as a heating medium.