Double trouble or double wins- A Dual Solution for Safety and Power in Rwanda
VEGA sensors provide an early warning system at Lake Kivu, ensuring accurate gas level monitoring for the early detection of potential gas eruptions, safeguarding both operations and safety
Lake Kivu presents a fascinating case study in limnology and geochemistry. Its unique characteristics are primarily driven by its location within the East African Rift Valley, a tectonically active region characterised by volcanic activity and high heat flow. The nearby Nyiragongo and Nyamuragira volcanoes contribute significantly to the lake’s geochemical composition as these volcanoes release large amounts of carbon dioxide (CO2), a key precursor to methane formation. The rift valley environment has led to the formation of a deep lake basin with a stratified water column. This stratification is crucial for the accumulation of gases at depth.
Organic matter from the lake’s ecosystem, including plankton and other organisms, sinks to the bottom, where it undergoes anaerobic decomposition by microbial communities. Without oxygen, certain microbes convert the organic matter into methane (CH4) as a byproduct of their metabolism. Due to its low solubility in water, methane accumulates in the lake’s deeper, colder layers, forming a gas-rich hypolimnion. The dissolved CO2 from volcanic sources also contributes to the gas accumulation, creating a potentially explosive mixture.
The high concentration of dissolved gases in Lake Kivu poses a significant risk of a limnic eruption, a rare but deadly event where the gases erupt to the surface, suffocating life in the surrounding area. However, the benefits in this case outweigh the risks- the methane reserves represent a substantial energy resource. The process of gas extraction and utilisation must be carefully managed to minimise environmental impacts on the lake ecosystem.
Resource Exploration and Extraction
Methane exploration in Lake Kivu has primarily focused on Gas Composition Analysis,determining the exact composition of the gas mixture, including methane, carbon dioxide, and other potential components, and Gas Quantity Estimation by assessing the total volume of methane available within the lake’s depths.
Various challenges presented themselves during the gas extraction process at Lake Kivu. Given the depth at which methane is concentrated, specialised equipment and techniques are required. Once extracted, the gas mixture is separated into its components, primarily methane and carbon dioxide. Environmental impact mitigation is to be considered, and careful planning is essential to minimise the impact of extraction on the lake’s ecosystem and surrounding communities.
KivuWatt is a notable example of a successful methane extraction and power generation project on Lake Kivu. It has demonstrated the feasibility of harnessing this unique resource while also highlighting the complexities involved. The extracted and processed methane is used as fuel for power plants to generate electricity. Alternatively, the methane can be utilised for industrial processes or converted into other energy forms.
Understanding the Challenge
Lake Kivu presented a unique set of challenges for instrumentation due to the extreme underwater environment, Instrumentation in this environment faces dire challenges- high pressure, low light, and corrosive conditions. Precise monitoring of gas levels and interfaces for safety and efficiency is of critical importance, and continuous operation in a demanding environment is crucial.
VEGA Instrumentation Solution
The VEGABAR 82 pressure transmitter was used for differential pressure measurement, the key to monitoring gas levels within the lake. It offers high precision and ensures accurate data for decision-making. Its rugged design is capable of withstanding the harsh underwater environment. The VEGAFLEX 81 level sensoris equipped with guided wave radar technology- ideal for level measurement in liquids and gases. Its accurate interface detection is crucial for determining the gas-liquid boundary. VEGA instrumentation is known for reliable operation, which in this application ensured consistent performance in challenging conditions.
Bypass chambers housed the instruments and provided a controlled environment for their operation. The 180-meter cable of the VEGAFLEX 81 allowed for data transmission from the underwater instruments to the surface control system.Real-time data received from the sensors are used to monitor gas levels, calculate extraction rates, and implement safety protocols.
VEGA sensors offer an early warning system where accurate gas level monitoring enables early detection of potential gas eruptions. It allows for optimised extraction rates at Lake Kivu, as precise measurements allow for efficient gas extraction without compromising safety. The VEGA instruments deployed in this application are key in the environmental aspect of the extraction process, as monitoring gas levels helps prevent gas leakage and protect the lake ecosystem. The successful deployment of these sensors in this challenging environment represents a significant technological advancement in data transmission and seamless integration in the extraction processes, as reliable data transfer over long distances underwater was essential for the project’s success. The seamless integration of instrumentation with the overall extraction system optimises operations, reducing cost and increasing safety.
The use of VEGA instrumentation in the Lake Kivu methane extraction project demonstrates the critical role of advanced technology in addressing complex engineering challenges. By providing accurate and reliable measurement data, VEGA contributed to the safe and efficient development of this vital energy resource.
For more info, please contact VEGA Instruments directly: www.vega.com
