Session: 10-01 Hydrogen Energy, Alternative Fuels, Bioenergy, and Biofuels

Paper Number: 106980

106980 - Investigation of the Effects of Hydrogen-Enriched Natural Gas Blends and Pure Hydrogen on the Performance of a Domestic Condensing Boiler 

Following increased awareness about the deleterious effects of climate change on the environment, many corporations and institutions are making concerted efforts to reduce their greenhouse gas emissions through policy reviews and  technological changes. One area of promise is the replacement of natural gas (NG) with hydrogen (H₂) for use in residential and industrial sectors. Hydrogen can play a significant role in reducing emissions in heating applications within the built environment. In a net-zero emissions future where distributed combustion emissions have to be largely eliminated, zero-carbon fuels and hydrogen solutions for heating are  some of the most cost-effective and flexible paths that will facilitate the sector’s energy transition. In the short term, hydrogen is currently being blended in small amounts into existing NG networks around the world. This has an impact on the performance of appliances designed for NG, as certain gas properties will change.

In this study, the effects of hydrogen on a domestic condensing boiler which was originally designed for NG, was investigated. The combustion reaction as a function of hydrogen content and oxygen content was determined. Stoichiometric, lean, and incomplete combustion were considered. Incomplete combustion leads to the formation of polluting emissions, while lean combustion is used to mitigate this by using excess air. An analytical model was developed to determine the outputs, that is, condensation efficiency, energy fraction of condensation, and exhaust gas specific heat, which were the main outputs that were systematically analyzed.

Results showed that water vapour in the exhaust gas had the most remarkable effect on properties, and in consequence, on the boiler’s operation. Optimum efficiency occurred when the molar fraction of water vapour was maximized. This corresponded to the combustion of pure hydrogen at stoichiometric conditions. It was further observed that pollutant emissions formation was minimized with greater amounts of excess air via lean combustion, which also resulted in a smaller water vapour fraction. The addition of hydrogen also reduced emissions since the only combustion product of pure hydrogen is water.

To optimize the economical and environmental benefits, it is recommended that pure hydrogen should be utilized in lean combustion conditions with low amounts of excess air. This guarantees greater performance over pure natural gas dispensed in the same conditions, while mitigating the formation of polluting emissions.

Presenting Author: Wahiba Yaici Natural Resources Canada / CanmetENERGY Research Centre

Presenting Author Biography: Dr. Yaïci is a Research Scientist at the CanmetENERGY Research Centre in Ottawa, Canada, where she is leading R&D projects in renewables and integrated energy systems. She leads and develops hybrid renewable power and energy technologies for building applications and for the electric vehicles. The focus of her research is on the experimental, modelling, simulation and optimisation using advanced simulation tools, CFD, Artificial Intelligence methods for the optimal design, performance and emissions predictions of micro-combined cooling, heat and power systems, solar/heat-driven tri-generation, thermal/thermo-chemical energy storage, NG/RNG/H2 vehicles, and hybrid energy storage systems for electric vehicles.

Previously, Dr. Yaïci worked also as Associate Professor, Technical Expert, Scientific Authority and Project Manager on many multi-million dollar R&D and large industrial projects at Natural Gas Technologies Centre (Energir-Engie), KSH (RWE), BPR-Bechtel (Tetra-Tech), and Rolls-Royce, in Montreal, Canada, where she has been a key contributor to projects related to fluid dynamics, aerodynamics, gas turbine aerothermal and combustion design, emissions abatement, development of combustion systems for ultra-low NOx emissions, catalytic reactors, ultra-low emissions heat generators, catalytic combustion in fixed and fluidized beds, emissions formation and reduction from power generation systems, synthesis from natural gas of high added value products, natural gas vehicle (CNGV & ANGV), process simulation and optimisation, CFD simulation of power generation and energy systems with detailed chemical kinetics.

She is author and co-author of several refereed journal and conference papers (130) and book chapters (10). She has also written more than 100 confidential reports for industrial projects.

She is reviewer for many international scientific journals, is a member of ASME, ASHRAE (was a voting member of the SPC204 Micro-CHP Standard), IEEE, IEEE Power & Energy Society, International Solar Energy Society (ISES), Canadian Artificial Intelligence Association (CAIAC), and is a Registered Professional Engineer in the province of Ontario, Canada (PEO).