pH Estimation for Silica-Supersaturated Fluids
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Solution Overview
Problem
Conventional pH measurement methods for silica-supersaturated fluids in geothermal power generation systems are inaccurate due to the heat resistance limitations of traditional pH meters and the adhesion of silica scale, leading to underestimation of silica content and increased costs for scale prevention systems.
Innovation Solution
A pH estimation system and method that measures silica concentration and temperature at multiple points in a fluid flow path, using a silica deposition prediction equation to calculate the pH of the fluid without direct pH measurement, thereby avoiding the limitations of traditional pH meters and scale adhesion issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a pH meter with a porous glass electrode is used to measure the pH of silica-supersaturated fluid, then the pH measurement can be performed, but scale adheres to the electrode and measurement accuracy deteriorates
Solution Approach 1:
The invention extracts the harmful factor (silica scale adhesion) from the measurement system by removing the porous glass electrode that causes adhesion. Instead of directly measuring pH with an electrode in contact with the fluid, the system measures silica concentration and temperature, then calculates pH indirectly, eliminating the adhesion problem entirely.
Solution Approach 2:
The invention replaces the mechanical/electrical pH measurement system (porous glass electrode) with a chemical measurement system (silica concentration and temperature measurement). By substituting the direct electrical measurement with chemical analysis and calculation, the system avoids the adhesion issue while obtaining pH information.
2Extent of automation
If a pH meter is used for automatic measurement of silica-supersaturated fluid, then pH data can be obtained, but additional scale prevention systems are required which increases cost
Solution Approach 1:
The invention merges the pH measurement function with the existing silica concentration measurement system. By using the same flow path and combining measurements of silica concentration and temperature, the system achieves automatic pH determination without requiring separate scale prevention systems or additional measurement equipment.
Solution Approach 2:
The invention makes the measurement system multi-functional by using it to obtain both silica concentration and temperature data, from which pH can be calculated. This universal approach eliminates the need for dedicated pH measurement equipment and scale prevention systems, reducing overall system cost while maintaining automation.
3Productivity
If steam is sampled at the outlet of a steam turbine to measure silica content, then automatic measurement is achieved, but silica that adhered before reaching the outlet is excluded leading to underestimation
Solution Approach 1:
The invention performs preliminary measurement by sampling the fluid before it enters the steam turbine, rather than at the outlet. This timing allows the system to capture all silica content including that which will subsequently adhere to the turbine, preventing underestimation while maintaining automatic measurement capability.
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
Accurately estimates the pH of silica-supersaturated fluids, providing valuable information for suppressing silica scale formation in a simple and economically advantageous manner, without the need for expensive scale prevention systems.
Implementation Method 1
a first measurement unit that is connected to the first flow path via an on-off valve; a second measurement unit that is connected to the second flow path via an on-off valve, wherein each of the first measurement unit and the second measurement unit includes a fluid temperature measurement device and a silica concentration measurement device
Implementation Method 2
each of the first measurement unit and the second measurement unit includes a fluid temperature measurement device and a silica concentration measurement device
Data Source
AI summary
A pH of a fluid is estimated without using a pH meter. A pH estimation system for a silica-supersaturated fluid includes: a first flow path that branches off from a pipe in which a fluid containing silica flows, and extracts a part of the fluid; a first measurement unit that is connected to the first flow path via an on-off valve; a retention portion that is connected to the first flow path; a second flow path that is connected to the retention portion and returns the fluid to the pipe; a second measurement unit that is connected to the second flow path via an on-off valve; and a computing device that is electrically connected to the first measurement unit and the second measurement unit, wherein the first measurement unit and the second measurement unit include a fluid temperature measurement device and a silica concentration measurement device; and the computing device stores a relational expression of a rate of decrease in a silica concentration, a silica saturation concentration, a temperature and a pH, and calculates the pH of the fluid, on the basis of measurement results in the first measurement unit and the second measurement unit and the relational expression.