Seawater Control Device for Marine Scrubber Emission Compliance
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Solution Overview
Problem
Existing seawater scrubbers face challenges in maintaining stable operation by accurately controlling the amount of seawater and alkali injection to ensure sulfur oxide concentration in exhaust gas does not exceed limit values, particularly due to reliance on pH meters for precise alkali control, which are prone to instability and calibration issues.
Innovation Solution
A system comprising a minimum seawater converter, seawater correction converter, summing element, and pump control device to calculate and supply the appropriate amount of seawater, and an alkali calculator and alkali pump control device to inject alkali into seawater, without relying on pH meters, ensuring the sulfur oxide concentration remains within limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an excessive amount of seawater is supplied to the scrubber, then the sulfur oxide concentration in exhaust gas is reduced below limit values, but the pressure loss increases and drive power of seawater pump increases
Solution Approach 1:
The system performs preliminary calculation of the minimum seawater amount required for effective sulfur oxide absorption based on engine output and fuel sulfur content. This pre-calculated baseline ensures sufficient absorption capacity is provided before exhaust gas enters the scrubber, preventing the need for excessive seawater supply and thereby reducing pump power consumption while maintaining compliance with emission limits.
Solution Approach 2:
The system incorporates feedback control by continuously monitoring the actual sulfur oxide concentration in treated exhaust gas and comparing it against calculated requirements. The amount of seawater supplied is dynamically adjusted based on this feedback, ensuring the minimum effective amount is used without oversupplying, thus optimizing energy consumption while maintaining reliable sulfur oxide removal.
2Use of energy by moving object
If an insufficient amount of seawater is supplied to the scrubber, then the drive power of seawater pump is reduced, but the sulfur oxide concentration in exhaust gas exceeds the limit value
Solution Approach 1:
The system calculates the minimum seawater amount required for effective sulfur oxide absorption in advance, based on engine output and fuel sulfur content. This pre-determined baseline ensures that sufficient seawater is supplied to meet emission requirements without needing to supply excessive amounts, thereby reducing pump power consumption while maintaining reliable compliance with sulfur oxide concentration limits.
Solution Approach 2:
The system uses feedback control to monitor actual sulfur oxide concentration in treated exhaust gas and dynamically adjusts seawater supply accordingly. This ensures the minimum effective amount of seawater is continuously supplied to maintain emission compliance, avoiding both insufficient supply (which would exceed limits) and excessive supply (which would waste energy).
3Measurement precision
If a pH meter is used for pH measurement and control, then alkali control precision is improved, but the system requires periodic cleaning and calibration and cannot provide stable measurement results
Solution Approach 1:
The system extracts and eliminates the pH meter from the measurement and control system. Instead of using pH measurement, the system calculates the required alkali amount directly from engine output and fuel sulfur content parameters, and controls alkali injection based on these calculations. This removes the source of measurement instability while maintaining precise alkali control through alternative means.
Solution Approach 2:
The system replaces the mechanical/electrical pH measurement system with a calculation-based control approach. Alkali injection is controlled based on calculated requirements derived from engine operating parameters and fuel composition, rather than based on real-time pH measurements. This substitution eliminates the need for periodic calibration and cleaning while maintaining reliable control precision.
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 achieves stable and reliable sulfur oxide removal by precisely controlling seawater and alkali injection, preventing excessive or insufficient seawater supply and maintaining sulfur oxide concentrations below emission limits without the need for pH measurement.
Implementation Method 1
a scrubber for reducing the concentration of sulfur oxides in the exhaust gas by bringing the sulfur oxide into contact with seawater
Data Source
AI summary
An amount of seawater control device controls an amount of seawater supplied to a scrubber that purifies sulfur oxide contained in exhaust gas by bringing the sulfur oxide into contact with seawater. The control device includes a minimum amount of seawater converter which calculates a minimum amount of seawater necessary for an absorption reaction of the sulfur oxide by the seawater, an amount of seawater correction converter which calculates a corrected amount of seawater which is an amount of seawater at which the sulfur oxide contained in the exhaust gas discharged into atmosphere from the scrubber is equal to or less than a set variable, a summing element which calculates a set amount of seawater by summing the minimum amount of seawater and the corrected amount of seawater, and a pump control device which implements control such that seawater corresponding to the set amount is supplied to the scrubber.