Sustainable CO2 Capture from Gas Flaring Using Calcium Hydroxide

Abstract Gas flaring is a widely used practice in the oil and gas industry, primarily employed to safely dispose of excess hydrocarbons that cannot be processed, stored, or transported. While this method is essential for operational safety and pressure regulation, it comes with a significant environmental cost—namely, the emission of large volumes of carbon dioxide (CO2), a potent greenhouse gas. CO2 emissions from gas flaring contribute substantially to global warming and climate change, making it imperative to develop and implement sustainable mitigation strategies. This paper introduces a novel and environmentally sustainable approach to CO2 capture from gas flaring operations using calcium hydroxide (Ca (OH)2) as a chemical scrubbing agent. The proposed system is designed to not only ensure the safe combustion of excess gases but also to actively capture and neutralize the CO2 produced during the flaring process. By integrating a CO2 scrubbing mechanism into the flaring system, this method significantly reduces the environmental footprint of gas flaring and aligns with global efforts to combat climate change. The system architecture comprises three main components: a Ground Flare Assembly, a CO2 Scrubbing Unit, and a set of automated control mechanisms. The process begins with the delivery of fuel gas to the burner through a dedicated gas line. The burner, equipped with a temperature sensor, ignites the gas and continuously monitors the combustion temperature. If the sensor detects optimal combustion conditions (i.e., high temperature), it triggers the closure of a shutter and the opening of an On/Off valve to maintain gas flow. Conversely, if the temperature drops indicating incomplete or failed combustion the shutter remains open, and the valve closes to safely vent unburned gas, preventing hazardous buildup. The Ground Flare Assembly is engineered for controlled and enclosed combustion. It includes multiple burners, a flow sensor to regulate gas input, and a fresh air blower that supplies the necessary oxygen to sustain efficient combustion. The exhaust gases generated comprising CO2 and other by-products are channeled through a main pipeline to the scrubbing unit. The CO2 Scrubbing Unit is the core of the emission reduction system. It utilizes a solution of calcium hydroxide (Ca (OH)2) to chemically react with CO2 in the flue gases. The gases pass through a series of three scrubbers, where they are exposed to the Ca (OH)2 solution. The primary chemical reaction involved is: CO2 (gas)+Ca (OH)2 (aqueous)→CaCO3 (solid)+H2O This reaction converts gaseous CO2 into calcium carbonate (CaCO3), a stable and non-toxic solid that can be safely stored or repurposed in various industries, such as construction or agriculture. The scrubbers are equipped with level sensors to monitor the volume of the Ca (OH)2 solution, ensuring that the system operates at peak efficiency. Once the solution becomes saturated with CaCO3, it is discharged through an outlet valve, and the treated exhaust gases now significantly reduced in CO2 content are vented through an exhaust valve. The integration of calcium hydroxide scrubbing into the gas flaring process offers multiple environmental, operational, and economic benefits. Environmentally, it directly reduces the amount of CO2 released into the atmosphere, contributing to climate change mitigation. The transformation of CO2 into a solid form also provides a method of long-term sequestration, effectively removing it from the atmospheric cycle. Operationally, the system enhances safety by ensuring complete combustion and preventing the release of unburned gases. Economically, the by-product calcium carbonate can be sold or reused, turning a waste stream into a valuable resource. Moreover, the system is designed with real-time monitoring and feedback controls, including CO2 sensors, temperature sensors, and flow regulators. These components work together to maintain optimal operating conditions, adjust chemical dosing, and ensure the highest possible scrubbing efficiency. The use of automation reduces the need for manual intervention and enhances the reliability and consistency of the process. In conclusion, the proposed CO2 capture system using calcium hydroxide scrubbing represents a sustainable, efficient, and scalable solution to the environmental challenges posed by gas flaring. It not only addresses the urgent need to reduce greenhouse gas emissions but also aligns with broader sustainability goals and regulatory frameworks. By converting harmful emissions into useful by-products and integrating advanced monitoring technologies, this system exemplifies how innovation in industrial processes can lead to both environmental stewardship and economic opportunity. As the oil and gas industry continues to evolve in response to climate imperatives, such technologies will play a critical role in shaping a cleaner, more sustainable future.