Flame Rectification Study for Natural Gas-Hydrogen-AirMixtures in Industrial Premixed Burners

<p class="p1" style="margin: 0px; font-width: normal; font-size: 9px; line-height: normal; font-family: Helvetica; font-size-adjust: none; font-kerning: auto; font-variant-alternates: normal; font-variant-ligatures: normal; font-variant-numeric: normal; font-variant-east-asian: normal; font-variant-position: normal; font-feature-settings: normal; font-optical-sizing: auto; font-variation-settings: normal;">Premixed combustion of hydrogen/natural gas fuel mixtures was experimentally investigated to address the chal- <p class="p1" style="margin: 0px; font-width: normal; font-size: 9px; line-height: normal; font-family: Helvetica; font-size-adjust: none; font-kerning: auto; font-variant-alternates: normal; font-variant-ligatures: normal; font-variant-numeric: normal; font-variant-east-asian: normal; font-variant-position: normal; font-feature-settings: normal; font-optical-sizing: auto; font-variation-settings: normal;">lenges of flame rectification and flame structure diagnostics. The industrial burner (i.e., PHOTON65 unit) was <p class="p1" style="margin: 0px; font-width: normal; font-size: 9px; line-height: normal; font-family: Helvetica; font-size-adjust: none; font-kerning: auto; font-variant-alternates: normal; font-variant-ligatures: normal; font-variant-numeric: normal; font-variant-east-asian: normal; font-variant-position: normal; font-feature-settings: normal; font-optical-sizing: auto; font-variation-settings: normal;">operated at atmospheric pressure. The burner’s control unit maintained and stabilized combustion, while precise <p class="p1" style="margin: 0px; font-width: normal; font-size: 9px; line-height: normal; font-family: Helvetica; font-size-adjust: none; font-kerning: auto; font-variant-alternates: normal; font-variant-ligatures: normal; font-variant-numeric: normal; font-variant-east-asian: normal; font-variant-position: normal; font-feature-settings: normal; font-optical-sizing: auto; font-variation-settings: normal;">fuel blends were achieved using mass flow controllers. Gradually, the natural gas content was reduced from 100% <p class="p1" style="margin: 0px; font-width: normal; font-size: 9px; line-height: normal; font-family: Helvetica; font-size-adjust: none; font-kerning: auto; font-variant-alternates: normal; font-variant-ligatures: normal; font-variant-numeric: normal; font-variant-east-asian: normal; font-variant-position: normal; font-feature-settings: normal; font-optical-sizing: auto; font-variation-settings: normal;">to 0% by volume, while the hydrogen content was increased from 0% to 100%. Different fuel mixtures were <p class="p1" style="margin: 0px; font-width: normal; font-size: 9px; line-height: normal; font-family: Helvetica; font-size-adjust: none; font-kerning: auto; font-variant-alternates: normal; font-variant-ligatures: normal; font-variant-numeric: normal; font-variant-east-asian: normal; font-variant-position: normal; font-feature-settings: normal; font-optical-sizing: auto; font-variation-settings: normal;">tested at a fixed airflow rate, while the fuel flow rate was varied to achieve a successful sustained flame on the <p class="p1" style="margin: 0px; font-width: normal; font-size: 9px; line-height: normal; font-family: Helvetica; font-size-adjust: none; font-kerning: auto; font-variant-alternates: normal; font-variant-ligatures: normal; font-variant-numeric: normal; font-variant-east-asian: normal; font-variant-position: normal; font-feature-settings: normal; font-optical-sizing: auto; font-variation-settings: normal;">industrial burner’s bed. In burner applications, flame detection is achieved using sensors that detect the presence <p class="p1" style="margin: 0px; font-width: normal; font-size: 9px; line-height: normal; font-family: Helvetica; font-size-adjust: none; font-kerning: auto; font-variant-alternates: normal; font-variant-ligatures: normal; font-variant-numeric: normal; font-variant-east-asian: normal; font-variant-position: normal; font-feature-settings: normal; font-optical-sizing: auto; font-variation-settings: normal;">of flame through an electric signal. This signal can be utilized by ignition and control systems. UV (ultra-violet) <p class="p1" style="margin: 0px; font-width: normal; font-size: 9px; line-height: normal; font-family: Helvetica; font-size-adjust: none; font-kerning: auto; font-variant-alternates: normal; font-variant-ligatures: normal; font-variant-numeric: normal; font-variant-east-asian: normal; font-variant-position: normal; font-feature-settings: normal; font-optical-sizing: auto; font-variation-settings: normal;">phototubes exploit the ultra-violet radiation emitted by the flame, which is particularly suitable for applications in <p class="p1" style="margin: 0px; font-width: normal; font-size: 9px; line-height: normal; font-family: Helvetica; font-size-adjust: none; font-kerning: auto; font-variant-alternates: normal; font-variant-ligatures: normal; font-variant-numeric: normal; font-variant-east-asian: normal; font-variant-position: normal; font-feature-settings: normal; font-optical-sizing: auto; font-variation-settings: normal;">enclosed industrial burners using gaseous fuels. This study employed a BRAHMA FD2 with a lateral view, and <p class="p1" style="margin: 0px; font-width: normal; font-size: 9px; line-height: normal; font-family: Helvetica; font-size-adjust: none; font-kerning: auto; font-variant-alternates: normal; font-variant-ligatures: normal; font-variant-numeric: normal; font-variant-east-asian: normal; font-variant-position: normal; font-feature-settings: normal; font-optical-sizing: auto; font-variation-settings: normal;">peak detection was approximately 310 nm for flame rectification purposes. Various axial positions and angular <p class="p1" style="margin: 0px; font-width: normal; font-size: 9px; line-height: normal; font-family: Helvetica; font-size-adjust: none; font-kerning: auto; font-variant-alternates: normal; font-variant-ligatures: normal; font-variant-numeric: normal; font-variant-east-asian: normal; font-variant-position: normal; font-feature-settings: normal; font-optical-sizing: auto; font-variation-settings: normal;">orientations were investigated to determine the optimal position of the UV sensor for hydrogen combustion flames. <p class="p1" style="margin: 0px; font-width: normal; font-size: 9px; line-height: normal; font-family: Helvetica; font-size-adjust: none; font-kerning: auto; font-variant-alternates: normal; font-variant-ligatures: normal; font-variant-numeric: normal; font-variant-east-asian: normal; font-variant-position: normal; font-feature-settings: normal; font-optical-sizing: auto; font-variation-settings: normal;">Additionally, flame visibility, flame blow-off, and flame sustainability were investigated to identify the most suit- <p class="p1" style="margin: 0px; font-width: normal; font-size: 9px; line-height: normal; font-family: Helvetica; font-size-adjust: none; font-kerning: auto; font-variant-alternates: normal; font-variant-ligatures: normal; font-variant-numeric: normal; font-variant-east-asian: normal; font-variant-position: normal; font-feature-settings: normal; font-optical-sizing: auto; font-variation-settings: normal;">able position for the UV sensor in all studied fuel blend cases. Flame height and structure undergo significant <p class="p1" style="margin: 0px; font-width: normal; font-size: 9px; line-height: normal; font-family: Helvetica; font-size-adjust: none; font-kerning: auto; font-variant-alternates: normal; font-variant-ligatures: normal; font-variant-numeric: normal; font-variant-east-asian: normal; font-variant-position: normal; font-feature-settings: normal; font-optical-sizing: auto; font-variation-settings: normal;">changes with an increasing percentage of hydrogen in the fuel mixture. The UV sensor provides a cost-effective <p class="p1" style="margin: 0px; font-width: normal; font-size: 9px; line-height: normal; font-family: Helvetica; font-size-adjust: none; font-kerning: auto; font-variant-alternates: normal; font-variant-ligatures: normal; font-variant-numeric: normal; font-variant-east-asian: normal; font-variant-position: normal; font-feature-settings: normal; font-optical-sizing: auto; font-variation-settings: normal;">and reliable solution for flame detection and rectification in space heating industrial burners.