Dilution Means for Pulp Transfer Stand Pipe
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Solution Overview
Problem
In the pulp and paper industry, transferring process liquids from washing and thickening devices to subsequent stages requires elevated installations due to fluctuating production rates, leading to inefficient dilution, inconsistent pulp consistency, and increased construction and energy costs, as well as potential quality issues from undiluted pulp segments.
Innovation Solution
A method and arrangement where the washing and thickening device is positioned at a lower level, allowing direct discharge to a stand pipe with integrated dilution means that maintain a higher average consistency within the stand pipe's surface level control range, reducing the need for additional floors and energy consumption by ensuring uniform dilution and consistent pulp flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the washing and thickening device is installed at a high level to ensure sufficient height for stand pipe and dilution, then the pumping of pulp from washing stage to subsequent process stage is ensured, but the construction cost and energy consumption increase due to elevated installation requirements
Solution Approach 1:
The invention applies preliminary action by performing dilution before the pulp enters the stand pipe. The dilution means is positioned to receive thick pulp from the washing and thickening device and dilute it before discharge into the stand pipe, ensuring that the pulp reaches the stand pipe at the correct consistency for reliable pumping without requiring elevated installation
Solution Approach 2:
The invention uses an intermediary approach by introducing a dilution means as a mediating component between the washing and thickening device and the stand pipe. This intermediary device enables the pulp to be diluted to the appropriate consistency before entering the stand pipe, eliminating the need for high-level installation while maintaining pumping reliability
2Reliability
If a high stand pipe is used to provide sufficient residence time for pulp surface level control, then the pump and washing device function without disturbance, but the construction cost increases due to additional floors or storeys
Solution Approach 1:
The dilution means performs preliminary dilution before pulp enters the stand pipe, ensuring that pulp reaches the stand pipe at the optimal consistency. This preliminary action reduces the required residence time and stand pipe height while maintaining operation stability
Solution Approach 2:
The invention changes the consistency parameter of the pulp before it enters the stand pipe by using the dilution means. By adjusting the pulp consistency to the appropriate range (8-15%) before stand pipe entry, the system achieves stable operation with a reduced stand pipe height
3Quantity of substance
If dilution is performed in advance before stand pipe entry, then the pulp consistency is reduced to 8-15%, but inconsistent dilution and undiluted pulp segments cause quality issues
Solution Approach 1:
The dilution means is designed with multiple dilution liquid conduits distributed across its cross-section, creating local dilution zones throughout the device. This ensures uniform dilution of the thick pulp as it passes through, preventing undiluted segments and maintaining consistent pulp quality
Solution Approach 2:
The dilution means is segmented into multiple sections with separate dilution liquid conduits in different regions of the device. This segmentation allows dilution liquid to be introduced at multiple locations simultaneously, ensuring thorough and uniform dilution of the entire pulp stream
4Ease of manufacture
If the washing and thickening device is positioned at ground floor level, then construction cost is reduced, but the ability to maintain sufficient dilution and pumping capability is compromised
Solution Approach 1:
The dilution means performs preliminary dilution at ground floor level, receiving thick pulp from the washing and thickening device and diluting it before discharge into the stand pipe. This preliminary action ensures that ground floor positioning does not compromise pumping capability or process efficiency
Solution Approach 2:
The dilution means acts as an intermediary device that enables ground floor installation by mediating between the washing and thickening device and the stand pipe. It ensures the pulp reaches the correct consistency for efficient pumping without requiring elevated installation, thus maintaining productivity while reducing construction cost
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 configuration allows for a more efficient and cost-effective transfer of pulp, reducing construction costs, energy consumption, and maintaining pulp quality by ensuring consistent dilution and reduced height requirements for the stand pipe, enabling the washing and thickening device to be located on the ground floor without compromising process efficiency.
Implementation Method 1
the process liquid is diluted in the stand pipe to a second consistency, i.e. to an MC-consistency
Implementation Method 2
the process liquid is discharged in the second consistency from the stand pipe by means of a pump arranged in flow communication with a discharge outlet opening provided in the stand pipe
Data Source
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AI summary
The present invention relates to a method of and an arrangement for transferring a process liquid from a washing and thickening device to a subsequent process stage. In accordance with an advantageous embodiment of the present invention, the method and the arrangement are applicable, for example, in transferring fibre suspensions or pulps from washing and thickening device to a subsequent process stage in pulp and paper making industry such that the dilution of pulp after a washing and thickening device is performed in a stand pipe (18) below the surface level control range.