Wet Scrubber Effluent Cleaning Using Cement-Activated Carbon Composite
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Solution Overview
Problem
Current methods for treating exhaust fumes from diesel engines on ships, particularly those using wet scrubbers, fail to efficiently and compactly remove organic pollutants due to limitations in filtration velocity, size constraints, and separation challenges with conventional adsorbents like activated carbon in seawater environments.
Innovation Solution
A method involving a mixture of cement and activated carbon, with specific particle sizes and proportions, is used to create solid particles that are denser than conventional adsorbents, allowing efficient adsorption of organic compounds and subsequent separation using hydrocyclones or centrifuges, facilitating compact and economical treatment of effluents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional activated carbon is used for adsorbing organic compounds in scrubber effluents, then adsorption efficiency is improved, but solid-liquid separation becomes difficult due to low density difference with seawater
Solution Approach 1:
The patent applies composite materials by combining activated carbon particles with magnetite (Fe3O4) magnetic particles to create a composite adsorbent. This composite structure maintains the high adsorption efficiency of activated carbon for organic compounds while introducing magnetic properties that enable easy separation from the liquid effluent using magnetic fields, thus resolving the contradiction between adsorption efficiency and separation ease.
2Productivity
If filtration velocity is increased to treat large flows, then productivity is improved, but filtration precision deteriorates requiring very large filtering installations
Solution Approach 1:
The patent replaces the conventional mechanical filtration system with a magnetic separation system. Instead of relying on slow filtration through porous media to achieve separation, the invention uses magnetic fields to rapidly separate the magnetic composite particles from the effluent. This substitution allows high flow rates to be treated while maintaining high separation efficiency, resolving the contradiction between productivity and precision.
3Device complexity
If decanting is used to remove organic compounds, then separation is simplified, but treatment effectiveness is insufficient for high-concentration flows
Solution Approach 1:
The invention creates composite particles combining activated carbon's adsorption capability with magnetite's magnetic properties and appropriate density. This composite structure enables the particles to be effectively removed from high-concentration effluents through magnetic separation, achieving both the simplicity of decanting and the effectiveness needed for high-flow, high-concentration treatment scenarios.
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 enables effective capture and separation of organic pollutants, overcoming the limitations of conventional methods by maintaining a high specific surface area for adsorption while ensuring efficient solid-liquid separation, even in high-flow seawater environments, thus providing a compact and economical solution for shipboard applications.
Implementation Method 1
the superior ability of activated carbon to capture organic compounds by adsorption
Implementation Method 2
the action of a solid-liquid separator towards which the effluents leaving the scrubber are directed. The invention advantageously makes it possible to use hydrocyclones as solid-liquid separator
Implementation Method 3
the invention therefore allows the astute imparting to these solid particles of a density that is much higher than that of conventional adsorbents
Data Source
Figure 1
AI summary
For simple, compact and economical cleaning of liquid effluents (4) from a wet scrubber (WS) treating exhaust fumes (1) emitted by a diesel engine (E), the invention provides that: - solid particles (7), containing between 25 and 75 % by weight of activated carbon and between 25 and 60 % by weight of cement and having a mean size of between 30 μm and 500 μm, are placed in the scrubber (WS), and - the effluents to be cleaned (4), on leaving the scrubber (WS), are sent to a solid-liquid separator (SLS) where the effluents are separated into a clear fraction (5) and a sludge (6) containing the solid particles (7).