Evaporator Distillate Purity via Caustic Silica Conversion
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Solution Overview
Problem
Evaporation equipment struggles to effectively remove volatile silica and organic compounds from distillate streams, leading to contamination issues, especially in heavy oil production processes where increased silica levels require higher operational costs and steam generator blowdown rates.
Innovation Solution
A vertical tube, falling film evaporator system with a caustic mixing system and multi-pass mist eliminator configuration is used to convert volatile silica into non-vapor silica hydroxide complexes, reducing contamination by employing a dilute caustic solution to react with silica and organic compounds, followed by wire mesh mist eliminators to produce high purity distillate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If evaporation equipment is used to treat waters containing volatile silica, then water treatment is achieved, but volatile silica contaminates the distillate stream
Solution Approach 1:
The patent applies preliminary action by injecting caustic solution into the feedwater stream before evaporation to convert volatile silica into non-volatile silica hydroxide complexes. This pre-treatment prevents silica volatilization during the evaporation process, ensuring high distillate purity without requiring additional post-treatment steps.
Solution Approach 2:
The invention changes the chemical parameters of the feedwater by adjusting pH through caustic injection. This parameter change transforms silica from a volatile form to a non-volatile hydroxide complex form, preventing contamination of the distillate stream while maintaining effective water treatment.
2Device complexity
If silica concentration in feedwater is low, then evaporation process is simpler, but volatile silica significantly contaminates the vapor stream
Solution Approach 1:
The system performs preliminary conversion of volatile silica to non-volatile complexes through caustic injection before evaporation. This approach maintains simple evaporation equipment while effectively preventing silica contamination in the vapor stream, regardless of initial silica concentration levels.
Solution Approach 2:
The caustic solution acts as an intermediary substance that facilitates the conversion of volatile silica to non-volatile forms. This intermediary chemical reaction prevents direct volatilization of silica during evaporation, solving the contamination problem without complicating the evaporation system itself.
3Loss of substance
If silica levels in distillate are reduced, then steam generator operational costs decrease, but more complex treatment processes are required
Solution Approach 1:
By performing preliminary silica conversion through caustic injection, the system prevents silica contamination at the source. This eliminates the need for complex post-evaporation treatment processes and reduces steam generator operational costs related to silica management, achieving both goals simultaneously.
Solution Approach 2:
The invention converts the harmful volatile silica into beneficial non-volatile silica hydroxide complexes through caustic treatment. This transformation turns a contamination problem into a solved issue, reducing operational costs without requiring complex treatment systems.
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 significantly reduces volatile contaminants in distillate, achieving purity levels below 0.05 ppm for total dissolved solids, 1.0 ppm for non-volatile organic carbon, and 0.2 ppm for silica, far exceeding previous evaporation methods, making the distillate suitable for steam generators in heavy oil recovery operations.
Implementation Method 1
employing a dilute caustic solution to react with silica and organic compounds, followed by wire mesh mist eliminators to produce high purity distillate
Implementation Method 2
Evaporation of waters containing various solutes has become routine in many industrial operations
Implementation Method 3
vertical tube, falling film evaporator system with a caustic mixing system and multi-pass mist eliminator configuration
Data Source
AI summary
A method and apparatus for producing high purity distillate in evaporators is useful for evaporation of waters where volatile silica or organic compounds are encountered such as in production of hydrocarbons from geological formations. An evaporator having a contaminant reduction system is provided. The contaminant reduction system includes an upflow first mist eliminator portion to remove entrained liquid droplets and produce an intermediate purity water vapor stream. A continuous spray system provides a spray of dilute caustic solution in a selected spray configuration for mass transfer contact with the passing intermediate purity water vapor stream, to remove volatile silica compounds therefrom, and produce a partially decontaminated steam stream having mist particles therein. An upflow second mist eliminator portion is provided to remove the residual mist particles, and produce a high purity water vapor stream. The high purity water vapor stream is condensed to provide a high purity distillate stream.