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Given the climate change crisis and the global need for clean energy, research and development in clean fuel production technologies is a priority. One of the new technologies that has received attention in this regard is the use of liquid oxygen (LOX) as a driver and factor in improving the efficiency of clean fuel production processes. In this article, we will take a closer look at the use of liquid oxygen in clean fuel production processes, the advantages and challenges of its use. Liquid oxygen is known as an important molecule in various industries. It turns into a liquid at a temperature of about -183 degrees Celsius and, due to its physical properties, can be used as an effective oxidant in chemical processes and combustion. Liquid oxygen is usually produced through the partial distillation process of liquid air at very low temperatures. Liquid oxygen is used in sensitive industries such as aerospace, medicine, and even the oil and gas industry due to its high purity.
The role of liquid oxygen in improving fuel combustion
Improved oxidizer-to-fuel ratio: In conventional combustion systems, air is used as the oxidizer, which is approximately 78% nitrogen. Nitrogen does not play an effective role in the combustion process and only reduces energy efficiency. In addition, the introduction of nitrogen into the combustion process, as well as the high temperatures that are created, causes the production of nitrogen oxides (NOx). These pollutants are known to be one of the main causes of air pollution and acid rain. In contrast, using liquid oxygen as the oxidizer increases the oxygen-to-fuel ratio and, due to the reduced volume of nitrogen, combustion is carried out more efficiently. This leads to more complete combustion, reduced greenhouse gas emissions, and increased fuel efficiency.
Application in combustion engines and turbine systems:
In engines and turbine systems used in various industries, including energy generation and aviation and space transportation, the use of liquid oxygen can significantly improve the performance of combustion systems. Liquid oxygen acts as a catalyst to accelerate combustion reactions and, due to the increased combustion temperature, is able to produce more energy. In the space industry, especially in space rockets, liquid oxygen is used as an oxidizer and fuel in rocket engines along with fuels such as liquid hydrogen. This technology is currently used in space projects by NASA and other space organizations.
The role of liquid oxygen in the production of renewable fuels
Green hydrogen production:
Green hydrogen is considered one of the clean and renewable fuels. To produce green hydrogen, water must be separated into hydrogen and oxygen using renewable energy (such as solar or wind energy). This process is known as electrolysis. In this process, liquid oxygen is used as a source of pure oxygen, which can be used in some electrolysis methods. The hydrogen produced in this method does not have any pollution and can be used as a clean fuel in hybrid vehicles or fuel cells in the future.
Support for biofuels (biodiesel and biopropane):
Biofuels such as biodiesel and biopropane are increasingly important in the production of clean and renewable energy. Liquid oxygen can play a vital role in the production processes of these fuels. The use of liquid oxygen in biochemical processes such as oxidation or modification of the molecular structures of biofuels improves the quality and efficiency of these fuels.
Advantages of using liquid oxygen in clean fuels
Reduces pollutants and greenhouse gases: One of the biggest benefits of using liquid oxygen in combustion processes is the significant reduction in the production of pollutants, especially greenhouse gases. Here’s how it works:
Reduction of nitrogen oxides (NOx):
During the combustion of fuels, part of the nitrogen in the air is usually converted into nitrogen oxides, which are the main cause of air pollution. These compounds are produced in high-temperature combustion processes. By using liquid oxygen, which does not contain nitrogen, the production of nitrogen oxides can be prevented and, as a result, outdoor air quality can be improved.
Reducing CO2 and other greenhouse gases:
In liquid oxygen combustion processes, the fuel burns more completely because more oxygen is available for the reaction. This reduces the amount of carbon dioxide (CO2) produced, as incomplete combustion produces more CO2.
Reducing the production of pollutants:
In addition to NOx and CO2, the use of liquid oxygen can in some cases also prevent the production of other toxic pollutants, such as sulfurs and suspended solids, that are seen in the combustion of conventional fossil fuels.
Increasing energy efficiency and effectiveness
The use of liquid oxygen can significantly increase the efficiency of combustion systems. This increase in efficiency is achieved in several ways:
More complete combustion of fuel:
In conventional combustion systems, there is not enough oxygen to completely burn the fuel. Nitrogen in the air reduces the oxygen-to-fuel ratio, which causes incomplete combustion and waste of energy. However, with liquid oxygen, oxygen is available in large quantities, which allows the fuel to burn more completely and thus extract more energy.
Reducing the need for additional fuel:
Due to more complete combustion, there is no need for additional fuel to provide more energy. This reduction in fuel consumption reduces costs and increases efficiency in industrial processes.
Improving efficiency in turbine engines and rockets:
In turbine engines and rocket engines that use liquid oxygen along with fuels such as liquid hydrogen, combustion occurs much more efficiently. This helps increase engine performance and improve power output.
Extending equipment life and reducing maintenance costs
The use of liquid oxygen in combustion and turbine systems increases the life of equipment and machinery due to more complete combustion and reduced pollutant production. These benefits are as follows:
Reducing wear and deposits in combustion engines:
In engines that use liquid oxygen, the rate of erosion and deposition in various parts of the engine is reduced due to the reduction in the production of pollutants such as carbon and sulfur. This allows the equipment to operate more efficiently for longer and require less repair and maintenance.
Reducing operating costs:
Increased fuel efficiency and reduced need for additional fuel directly lead to lower operating costs. In addition, reduced pollutant production also reduces costs from environmental fines and the need for air purification systems.
Supporting the development of new technologies
The use of liquid oxygen will help develop new technologies not only now but also in the future. Technologies such as the production of clean fuels from renewable sources, hydrogen fuel cells, and even ultrafast combustion systems that could be used in the aerospace and advanced transportation industries all benefit from liquid oxygen.
These technologies could play an important role in reducing dependence on fossil fuels and providing sustainable energy. In addition, improving technologies for using liquid oxygen could reduce the costs of producing and storing this material on an industrial scale.
Despite its many benefits, the use of liquid oxygen in the production of clean fuels also comes with challenges. Among these challenges are the high cost of producing liquid oxygen and storing it at very low temperatures. Also, distributing and transporting this material on an industrial scale can be difficult. In this regard, further research is necessary to reduce costs and improve liquid oxygen storage and transportation technologies.
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