Flash Evaporator for Produced Water Cooling and Feedwater Preheating
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Solution Overview
Problem
The existing methods for cooling hot produced water to pre-heat steam generator feedwater in steam-assisted gravity drainage (SAGD) processes face issues with scaling and fouling, which degrade heat transfer effectiveness and require frequent service interruptions.
Innovation Solution
The process involves flash evaporation of produced water to produce vapor, which is then used to preheat steam generator feedwater through a non-contact, indirect heat transfer method, avoiding direct contact with heat exchanger surfaces and thus minimizing fouling and scaling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If liquid-to-liquid heat exchange is used to cool produced water and preheat steam generator feedwater, then heat transfer effectiveness is improved, but heat exchange surfaces become fouled and scaled requiring service interruptions for cleaning
Solution Approach 1:
The patent introduces steam as an intermediary medium to transfer heat from produced water to steam generator feedwater. Instead of direct liquid-to-liquid heat exchange that causes fouling, the system uses steam generated from produced water to preheat feedwater, eliminating contact between contaminated produced water and heat exchange surfaces. This resolves the contradiction by maintaining heat transfer effectiveness while preventing fouling that would require service interruptions.
Solution Approach 2:
The patent utilizes phase transition of water from liquid to steam through flash evaporation. Hot produced water is flashed to generate steam, which then condenses on heat exchange surfaces to transfer heat to feedwater. The phase change process enables efficient heat transfer while the steam and condensate can be easily separated from the contaminated produced water, preventing fouling and allowing continuous operation.
2Temperature
If produced water is cooled to remove excess thermal energy, then produced water temperature is reduced for optimal cleaning, but heat transfer surfaces become fouled with precipitated contaminants
Solution Approach 1:
The patent extracts the thermal energy from produced water by using it to generate steam through flash evaporation. The steam is then separated from the cooled produced water and used to preheat feedwater. This extraction process removes excess heat while preventing contaminants from contacting heat exchange surfaces, as the heat transfer occurs through steam condensation rather than direct contact with cooled produced water.
Solution Approach 2:
The patent converts the harmful effect of hot produced water (which causes fouling when cooled through direct heat exchange) into a beneficial process. The high temperature produced water is used to generate steam, and the steam's latent heat is used to preheat feedwater. This transforms the problematic thermal energy into a useful resource while eliminating the fouling issue associated with traditional cooling methods.
3Manufacturing precision
If produced water is treated to improve water quality for steam generation, then feedwater quality is improved, but substantial cleaning energy is consumed
Solution Approach 1:
The patent uses flash evaporation to separate contaminants from produced water based on phase transition. The produced water is flashed to steam, leaving contaminants behind in the liquid phase. The steam is then condensed to produce high-quality feedwater for the steam generator. This phase-based separation achieves excellent feedwater quality without requiring substantial chemical or mechanical cleaning energy, as the separation occurs naturally through evaporation and condensation.
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 enhances the efficiency of steam generation by pre-heating feedwater while preventing fouling and scaling, leading to improved heat transfer performance and reduced maintenance needs.
Implementation Method 1
The produced water is subjected to an evaporation process where a portion of the produced water is evaporated to produce a vapor
Implementation Method 2
Heat from the vapor is transferred to steam generator feedwater to preheat the steam generator feedwater
Implementation Method 3
Heat from the steam comes from sensible heat as the steam cools and latent heat as the steam condenses into water
Data Source
AI summary
An oil recovery process where produced water is cooled through a flash evaporization process and the resulting vapor is utilized to heat steam generator feedwater.