Geothermal Re-Injection Line Cleaning for Scale Dilution Control
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Solution Overview
Problem
The adhesion of scale, primarily composed of calcium and dissolved silica, within the piping of geothermal power generation systems, particularly in re-injection lines, leads to blockages and requires thorough cleaning, which is challenging due to the dilution of detergents as they travel downstream, resulting in insufficient cleaning.
Innovation Solution
A geothermal power generation system incorporating a chemical agent injection system with a controller that switches chemical agent and dissolving agent injections based on real-time analysis by a liquid analyzer, ensuring effective cleaning of the re-injection line by using a combination of tracer reagents, detergents, and corrosive agents, along with a scale-piece collector to remove adhered scale.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If detergent is supplied in the re-injection line, then scale adhesion is prevented, but the detergent is diluted as it travels downstream resulting in insufficient cleaning
Solution Approach 1:
The re-injection line is divided into multiple sections with chemical agent injection ports positioned at different locations (upstream and downstream of the pump). This segmentation allows detergent to be injected at multiple points along the line, ensuring sufficient concentration at each injection point and preventing the dilution problem that occurs with single-point injection.
Solution Approach 2:
The chemical agent is injected into the re-injection line before the geothermal brine reaches the downstream sections. By performing the injection action in advance at multiple locations, the detergent has sufficient time to mix with the brine and maintain effective concentration throughout the line, preventing scale adhesion before it occurs.
2Reliability
If chemical agent is injected to clean scale, then blockages are prevented, but the system requires multiple injection ports and control mechanisms increasing device complexity
Solution Approach 1:
The controller receives signals from the chemical agent detection device (which detects tracer reagents) and adjusts the injection operation of the chemical agent accordingly. This feedback mechanism allows the system to automatically optimize cleaning effectiveness while managing the complexity of multiple injection ports through intelligent control based on real-time detection data.
Solution Approach 2:
Tracer reagents with distinct colors or optical properties are injected into the re-injection line to make the chemical agent flow visible and detectable. This allows the chemical agent detection device to easily track and detect the presence and position of the chemical agent, simplifying the control mechanism by providing clear visual feedback on injection effectiveness.
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 effectively cleans the re-injection line by ensuring the chemical agents reach and dissolve scale efficiently, preventing blockages and maintaining system functionality.
Implementation Method 1
a dissolving agent adding device configured to inject a dissolving agent into the dissolving agent injection port
Implementation Method 2
a chemical agent adding device configured to inject a chemical agent into the chemical agent injection port... a controller configured to switch between an injection operation and injection stoppage of the chemical agent performed by the chemical agent adding device, based on an analysis result of the liquid analyzer
Implementation Method 3
a re-injection pump provided in the re-injection line and configured to return the geothermal brine discharged from the retention tank to the re-injection well
Implementation Method 4
a gas-liquid separator configured to separate geothermal brine and geothermal steam from a geothermal fluid spouted out from a production well
Implementation Method 5
a power generator configured to generate power by using the geothermal brine or the geothermal steam separated by the gas-liquid separator as a heat source
Implementation Method 6
a first chemical agent adding device configured to inject a chemical agent into the chemical agent injection port... a controller configured to switch between an injection operation and injection stoppage of the chemical agent
Data Source
AI summary
A geothermal power generation system includes: gas-liquid separator; power generator; retention tank; re-injection line; re-injection pump; chemical agent injection port in the re-injection line between the retention tank and the re-injection pump; first chemical agent adding device to inject a chemical agent into the chemical agent injection port; branching section in the re-injection line on a downstream side relative to the re-injection pump as well as on a vertically upper side of the re-injection well, and to branch a flow of geothermal brine; first liquid analyzer; scale-piece collector; dissolving agent adding device; and controller to switch between an injection operation and injection stoppage of the chemical agent by the first chemical agent adding device and to switch between an injection operation and injection stoppage of the dissolving agent by the dissolving agent adding device, based on an analysis result of the first liquid analyzer.