Exhaust Air Devaporization via Supply Air Mixing
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Solution Overview
Problem
The existing methods for reducing fog formation in the exhaust air from fiber track production systems, such as paper or pulp lines, are energy-intensive and require significant technical effort, leading to increased energy consumption and potential corrosion issues, making them economically unfeasible and inefficient.
Innovation Solution
A procedure that involves mixing a partial current of supply air with higher temperature and lower relative moisture into the exhaust air from the drying section, allowing for retrofitting in existing systems without substantial additional energy or structural measures, by branching off a portion of the supply air and mixing it with the exhaust air to lower the dew point and relative humidity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If additional energy is expended to heat the exhaust air flow beyond the condensation point, then fog formation is prevented, but energy consumption increases significantly
Solution Approach 1:
The invention changes the temperature and humidity parameters of the exhaust air by mixing it with hot supply air. Instead of heating the entire exhaust air flow, a portion of the hot supply air (which has already been heated for the drying process) is mixed with the exhaust air, changing its temperature and relative humidity parameters to prevent condensation and fog formation without additional energy input.
Solution Approach 2:
The system uses the hot supply air that is already being heated for the drying process to also serve the purpose of preventing fog formation in the exhaust air. The supply air fan and heating infrastructure serve dual purposes: providing hot air for drying and providing hot air for mixing with exhaust air to prevent condensation, eliminating the need for separate heating systems.
2Object-affected harmful factors
If a separate heat exchanger and blower system are provided for vapor removal, then fog formation is prevented, but device complexity increases
Solution Approach 1:
The invention merges the fog prevention function with the existing supply air system. The supply air fan, heating infrastructure, and exhaust air mixing process are combined into a unified system. The supply air serves dual purposes: providing hot air for the drying process and providing hot air for mixing with exhaust air to prevent condensation, eliminating the need for separate heat exchangers and blower systems.
Solution Approach 2:
The supply air system is designed to perform multiple functions: it provides hot air for the drying process and simultaneously provides hot air for mixing with exhaust air to prevent fog formation. This multi-functionality eliminates the need for dedicated equipment for each function, reducing overall system complexity.
3Object-affected harmful factors
If outside air is additionally extracted for vapor removal, then fog formation is prevented, but energy consumption increases
Solution Approach 1:
The invention recovers the thermal energy from the hot supply air that would otherwise be wasted after serving the drying process. By diverting a portion of this already-heated supply air to mix with the exhaust air, the system recovers thermal energy that would have been discarded, preventing fog formation without the energy cost of heating additional outside air.
4Object-affected harmful factors
If the process air is cooled to remove vapor, then fog formation is prevented, but condensation occurs inside the exhaust air system leading to corrosion
Solution Approach 1:
Instead of cooling the exhaust air to prevent fog formation (which causes condensation and corrosion), the invention inverts the approach by heating the exhaust air through mixing with hot supply air. This raises the dew point temperature above the ambient temperature, preventing condensation and corrosion while still eliminating fog formation.
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 approach effectively reduces fog formation without significant energy expenditure, is cost-effective, and can be easily integrated into existing systems, maintaining operational efficiency and reducing corrosion risks.
Implementation Method 1
a partial flow is branched off from the supply air and mixed with the exhaust air before being discharged to the environment
Implementation Method 2
The supply air has a higher temperature and a lower relative humidity than the exhaust air
Data Source
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AI summary
The invention relates to a method for the devaporization of process exhaust air generated by a plant that produces or processes a fibrous web, in particular a pulp web, paper web or cardboard web, wherein the installation has a dry end in which the fibrous web is at least partially dried by means of contact drying, wherein supply air is supplied to the dry end and exhaust air is discharged from the dry end, and wherein the supply air has a higher temperature and a lower relative humidity than the exhaust air, and a partial flow is branched off from the supply air and mixed with the exhaust air before being discharged into the surroundings, thus producing the process exhaust air.