Fluidized Bed Crystallizer for Scaling Control in Mechanical Vapour Compression
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Solution Overview
Problem
The presence of dissolved minerals, particularly calcium carbonate, in feed water limits the operating temperature and efficiency of mechanical vapor compression water treatment systems, leading to scaling issues that require frequent cleaning or chemical treatment, resulting in downtime.
Innovation Solution
Incorporating a fluidized bed crystallizer in the recirculation circuit to remove dissolved minerals such as magnesium and calcium compounds, allowing for increased operating temperature and reduced scaling by precipitating these minerals onto seed particles, which can be easily removed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the operating temperature of the mechanical vapor compression system is increased to improve efficiency, then the system efficiency and cost-effectiveness improve, but calcium carbonate precipitates forming scale on internal components
Solution Approach 1:
The fluidized bed crystallizer performs preliminary removal of calcium carbonate from the feed water before it enters the evaporation/condensation vessel. By precipitating calcium carbonate in the crystallizer at controlled conditions, the harmful scaling is prevented before it can form on the heat transfer surfaces during high-temperature evaporation, allowing the system to operate at higher temperatures without scaling issues
Solution Approach 2:
The fluidized bed crystallizer acts as an intermediary component between the feed water supply and the evaporation/condensation vessel. It introduces a separate stage where calcium carbonate is selectively removed through controlled precipitation, serving as a buffer that protects the main evaporation system from scaling while enabling efficient high-temperature operation
2Object-affected harmful factors
If chemical treatment or periodic cleaning is applied to remove scale, then scaling is reduced, but system downtime increases and operational complexity increases
Solution Approach 1:
By removing calcium carbonate in advance through the fluidized bed crystallizer, the system eliminates the need for periodic chemical cleaning or mechanical scale removal. The preliminary precipitation action prevents scale accumulation, allowing continuous operation without shutdowns for maintenance
Solution Approach 2:
The fluidized bed crystallizer provides self-service scale removal by continuously precipitating calcium carbonate from the recirculated brine. The crystallizer automatically captures and removes scale-forming minerals, eliminating the need for external chemical treatments or manual cleaning operations
3Object-affected harmful factors
If chemical treatment is used to reduce scale, then scaling is controlled, but additional chemicals and operational complexity are required
Solution Approach 1:
The system replaces chemical treatment methods with a mechanical/physical process - the fluidized bed crystallizer uses mechanical agitation and controlled precipitation to remove calcium carbonate. This substitution eliminates the need for chemical additives and complex chemical dosing systems, reducing operational complexity while effectively controlling scaling
Solution Approach 2:
The crystallizer system is self-regulating, using the natural precipitation properties of calcium carbonate at controlled temperatures and concentrations. The system automatically removes scale-forming minerals without requiring external chemical treatments or complex operational interventions
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
The solution effectively reduces dissolved solids in the feed water, increases the operating temperature of the evaporation/condensation vessel, and minimizes downtime by preventing scaling, thereby enhancing the system's efficiency and cost-effectiveness.
Implementation Method 1
passing at least part of the recirculated brine through the fluidized bed crystallizer to remove dissolved minerals therefrom
Implementation Method 2
fluidized bed crystallizer
Implementation Method 3
drive is applied to a compressor to compress and drive vapour within the system
Implementation Method 4
the heat required to evaporate the feed water which flows on one side of a heat transfer surface
Implementation Method 5
is supplied through the simultaneous condensation of product on the other side of the surface
Implementation Method 6
the system continually recycles and maintains the latent heat exchanged in evaporation and condensation
Data Source
AI summary
A water treatment system comprising a mechanical vapour compression apparatus (11), the mechanical vapour apparatus having a evaporation/condensation vessel (11a) and a recirculation circuit (20) whereby recirculated water is pumped from an outlet (18a) of the evaporation/condensation vessel (11A) to an inlet (18B) of the evaporation/condensation vessel (11A), wherein the recirculation circuit (20) comprises a fluidized bed crystallizer (22), and at least part of the recirculated brine is passed through the fluidized bed crystallizer (22) to remove dissolved minerals therefrom.