Marine Scrubber Flow Rate Calculation Using Nozzle Pressure
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Solution Overview
Problem
Existing systems for measuring the total flow rate of washing liquid at the inlet of a wet scrubber in marine vessels are costly, space-intensive, and require frequent maintenance, while providing less reliable results due to the need for multiple flow sensors that are difficult to install effectively.
Innovation Solution
A system comprising multiple spraying nozzles at different heights within the scrubber pipe, with a pressure sensor measuring pressure applied to the uppermost active nozzle, and a process controller calculating the flow rate using a formula that incorporates pressure and height corrections, allowing for the determination of total flow rate with reduced space and maintenance needs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If flow sensors are installed at the inlet of each wet scrubber to measure washing liquid flow rate, then measurement reliability is improved, but device complexity and installation difficulty increase due to space requirements
Solution Approach 1:
The invention extracts the measurement function from the traditional flow sensor at the scrubber inlet and relocates it to the spray nozzle level. By measuring pressure at the nozzle (where space is available) and calculating flow rate through formula Qind=K×√(P−pressure correction+height correction), the system eliminates the need for complex inlet flow sensor installations while maintaining measurement reliability.
Solution Approach 2:
The invention replaces the mechanical flow sensor system with a pressure measurement system combined with mathematical calculation. Instead of directly measuring flow rate mechanically at the inlet, the system measures pressure at the nozzle and uses the formula Qind=K×√(P−pressure correction+height correction) to calculate flow rate, simplifying installation and maintenance.
2Measurement precision
If multiple flow sensors are installed to measure total flow rate accurately, then measurement completeness is improved, but cost and maintenance requirements increase
Solution Approach 1:
The invention uses a single pressure sensor that sequentially or simultaneously measures pressure at multiple spray nozzle locations to obtain flow rate information for all nozzles. This copying approach allows one sensor to replace multiple sensors, reducing system cost while maintaining complete flow rate measurement capability through the calculation formula.
Solution Approach 2:
The pressure sensor serves multiple functions: it measures pressure for flow rate calculation, provides data for individual nozzle flow rates, and enables total flow rate determination. This multi-functionality eliminates the need for separate flow sensors at each location, reducing overall system cost and maintenance requirements.
3Productivity
If flow sensors are installed in confined spaces of marine vessels, then measurement capability is achieved, but installation feasibility deteriorates due to space constraints
Solution Approach 1:
The invention moves the measurement point from the horizontal inlet dimension to the vertical spray nozzle dimension. By installing pressure sensors at nozzle locations (which have access from the exterior or upper sections of the scrubber), the system bypasses the confined inlet space problem and enables easy installation while maintaining measurement capability.
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 solution provides a more reliable, cost-effective, and space-efficient method for measuring the total flow rate of washing liquid, enabling easier retrofitting of existing systems and improving data accuracy.
Implementation Method 1
at least one pressure sensor arranged to measure a pressure P applied to the uppermost active spraying nozzle
Implementation Method 2
calculating the flow rate Q of the washing liquid flowing through each of the individual active spraying nozzles, expressed in litre per minute or m3/h, using the formula: Qind=K×√{square root over ((P)}−pressure correction+height correction)
Data Source
AI summary
The present application relates to a system and method to determine a total flow rate Qtot of a washing liquid at a washing liquid inlet of an exhaust gas cleaning unit installed in a marine vessel, the exhaust gas cleaning unit comprising a scrubber pipe and two or more spraying nozzles mounted at different height levels in the scrubber pipe, being adapted to spray washing liquid into the exhaust gas present in the scrubber pipe and being operated by a valve adapted to open and to close the respective spraying nozzle. The system comprises at least one pressure sensor arranged to measure the pressure P outside the scrubber pipe before the valve operating the uppermost active spraying nozzle, and a process controller calculating the total flow rate Qtot of the washing liquid at the exhaust gas inlet of the exhaust gas cleaning unit by summing up the flow rate Qind of the washing liquid flowing through each of the individual active spraying nozzles.