Recirculating Concentrator–Crystallizer Evaporation for Fouling Control
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Solution Overview
Problem
Conventional waste water treatment systems are inefficient and require multiple unit operations, making them costly and inefficient for treating contaminated scrubber water from industrial processes.
Innovation Solution
A simplified system with a high circulation rate through an evaporation unit to create a concentrated crystallized waste product and purified effluent, using a recirculation loop, inducer, and a free-flow primary heat exchanger to minimize fouling and enhance heat transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional waste water treatment systems use multiple unit operations in series, then treatment effectiveness is achieved, but system complexity and operational cost increase
Solution Approach 1:
The patent combines multiple unit operations (evaporation, crystallization, heat exchange) into a single integrated system where waste water is processed through a continuous circulation loop. The evaporation unit with recirculation combines concentration and crystallization functions, while the heat exchanger integrates heat recovery and preheating operations, eliminating the need for separate sequential treatment stages.
Solution Approach 2:
The circulation system performs multiple functions simultaneously: the pump maintains continuous flow, the heat exchanger provides both heating and heat recovery, and the evaporation unit accomplishes both concentration and crystallization. This multi-functionality reduces the number of dedicated components needed while maintaining treatment effectiveness.
2Productivity
If high circulation rate is used through evaporation unit, then crystallization efficiency and water purification improve, but energy consumption increases
Solution Approach 1:
The system maintains continuous circulation of waste water through the evaporation unit, ensuring that the liquid phase continuously contacts the crystallization surface. This continuous action prevents interruption in crystal formation and allows sustained high-rate crystallization without periodic stopping or batch processing, maximizing productivity per unit energy input.
Solution Approach 2:
The recirculation system creates a feedback loop where concentrated solution is continuously returned to the evaporation unit after partial crystallization. This feedback mechanism maintains optimal concentration levels for crystallization and allows the system to self-regulate, improving efficiency by reusing the concentrated stream rather than discarding it.
3Reliability
If recirculation loop with high circulation rate is implemented, then fouling is minimized and heat transfer efficiency is maintained, but device complexity increases
Solution Approach 1:
The system uses dynamic recirculation flow rather than static batch processing. The continuous movement of liquid through the heat exchanger and evaporation unit prevents fouling by constantly renewing the liquid film in contact with heat transfer surfaces. This dynamic approach maintains heat transfer coefficients without requiring complex cleaning mechanisms or multiple exchangers.
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 system achieves efficient crystallization of waste products, reducing disposal volume and operational costs by increasing concentration and purifying water to 80-100% efficiency, minimizing fouling, and maintaining heat transfer efficiency.
Implementation Method 1
transferring heat from a pressurized distillate stream to a circulation stream in a primary heat exchanger
Implementation Method 2
evaporating volatile compounds from the heated circulation stream in the evaporation unit to form a distillate stream and a concentrated bottoms stream
Implementation Method 3
passing the distillate stream through a compressor to form the pressurized distillate stream
Data Source
AI summary
An aqueous stream cleaning system including a circulation pump to receive a waste fluid and/or a concentrated liquid bottoms stream, and expel a circulation stream. The aqueous stream cleaning system can also include a primary heat exchanger to receive the circulation stream from the circulation pump. The primary heat exchanger can have a plurality of heat exchange plates that define an internal surface area for heat transfer from a distillate stream to the circulation stream to produce a cooled distillate stream and a heated circulation stream. The plurality of heat exchange plates can be spaced to facilitate free flow of solids in the circulation stream between the plurality of heat exchange plates. A mass flow rate and pressure of the circulation stream can be configured to minimize build-up of solids in the primary heat exchanger. The aqueous stream cleaning system can further include an evaporation unit to receive the heated circulation stream from the primary heat exchanger. The distillate stream is formed when steam in the heated circulation stream evaporates in the evaporation unit, and the concentrated liquid bottoms stream is formed from a portion of the heated circulation stream that does not evaporate.