Research into the Possibilities of Burning Hydrogen and Fossil Fuel with the Aim of Reducing its Carbon Footprint
Abstract
Requirements for increasing the environmental friendliness of electricity and heat production to reduce the emission footprint are increasing the demands on the used fuels. For the replacement of conventional fuels in the process of combined production of electricity and heat, it is possible to use synthetic gases, which are created during processes of thermal recovery of biomass and waste. The presented article discusses the possibilities of using synthesis gas obtained by thermal recovery of waste in a plasma reactor in cogeneration units. For the experiment, different ratios of mixtures of natural gas and synthesis gas were used to reduce the consumption of fossil fuel without significantly reducing the performance of the cogeneration unit. The primary combustibles in the synthesis gas were hydrogen and carbon monoxide, the calorific value of which differs from that of methane, causing changes in fuel consumption to maintain the required unit performance. For the full possibility of using synthesis gas as a replacement in cogeneration units, further research is necessary both in the field of its use in combustion engines and in the field of its acquisition and primary purification.
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Introduction
Between 2010 and 2020, it is possible to observe a total decrease in the production of greenhouse gases in the form of CO2. This decrease is caused by many factors, including the global COVID-19 pandemic, which caused a significant slowdown in the economy in 2020, and the associated lower amount of CO2 emissions produced. In addition to this sudden drop in production, the EU's commitment to meeting the requirements of the Kyoto Protocol and the provisions on the decarbonization of Europe by 2050 has a significant impact on reducing CO2 emissions.
The decrease in the amount of CO2 produced in Slovakia between 2010 and 2020 was around 19%, while to meet the EU requirements for the overall reduction of CO2 production, an increase in efforts and thus more significant changes in the field of industry and transport are necessary. The total amount of CO2 produced by transport in Slovakia in 2020, including both passenger and freight transport, amounted to 31.163 mil. tons. According to the data of the Statistical Office of the Slovak Republic, the share of CO2 production by transport in the total amount of CO2 produced is increasing, which increased from 6.08% to 12.52% between 2010 and 2020 [1]. Due to the significant increase in the share of transport in the total production of CO2, it is necessary to focus on reducing CO2 not only in industry, but also in transport. Increasing the use of hydrogen in transport has a significant impact on the elimination of CO2 production and increases the possibilities of meeting the EU's decarbonisation goals.
Conclusion
In many cases, attention to the alternative energy market is devoted to solar energy, water and geothermal energy, while the energy stored in waste and their negative impact on the environment are often forgotten. The production of a gas mixture, with most of the hydrogen and carbon monoxide, represents a possible available source of energy and a high-quality input raw material for the chemical industry. Hydrogen, which forms a significant percentage of the gas mixture generated during hightemperature gasification, is also considered an alternative to replace fossil sources.
The significant deployment of hydrogen as a fuel requires a perfect mastery of technological and safety aspects and the creation of a sufficient portfolio of offered solutions, which will be based on modern hydrogen storage systems and alternative gaseous fuels with a high proportion of H2, as well as variable methods of hydrogen valorisation. One of the mentioned solutions enabling the transition of continuous transformation of technologies based on fossil fuels to green technologies is also the use and valorisation of secondary gaseous fuels. The conclusions valid for the implemented experimental trial can be defined in the following points.
Mixing the cleaned synthesis gas into the natural gas stream offers a real possibility of energy recovery of the synthesis gas produced in the gasification process. Gasification of waste with a high proportion of organic fraction, in addition to hygienic disposal and reduction of waste volume, also brings benefits in the form of energy recovery of otherwise unused waste, which usually ends up in managed or black landfills.
Dosing synthesis gas into the natural gas stream resulted in a reduction of CO emissions in the exhaust gases. By burning a mixture of synthesis gas and natural gas in cogeneration units, with fully automated control of the dosing of combustion air, fuel and the control of emerging emissions, it is possible to assume a more ecologically favourable operation of electricity production,
No operational problems were noted when burning the gaseous fuel mixture in accordance with tab.1. Reduced resistance to knocking in the engine cylinder was not noted at the volume fraction of hydrogen in the fuel at the level of 17.6 vol. %.