Application of a Robust Thermoelectric Gas Sensor in Firewood Combustion Exhausts

Hagen, Gunter; Herrmann, Julia; Zhang, Xin; Kohler, Heinz; Hartmann, Ingo; Moos, Ralf

doi:10.3390/s23062930

Cited by 5 publications

(4 citation statements)

References 24 publications

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“…Monitoring of CO/HC: In the past, the development of a wood-log combustion air control concept, as introduced above, was restrained because CO/HC-sensor elements with sufficient long-term stability enabling continuous in-situ monitoring of the CO/HC-content in the flue gas were not available. Faced with the relevance of this sensor element for biomass combustion control, in the last five years, several investigations were started to close this gap by further development of an existing sensor device [ 30 ] and introduction of new sensor concepts [ 25 , 31 , 32 ]. At the actual technological status, there is only one type of sensor, which is commercially available and has gained sufficient sensitivity and long-term stability at in-situ operation in the flue gas of wood-log combustion processes.…”

Section: Methods Of Sensor-based Air Stream Control For Optimization ...mentioning

confidence: 99%

Extensive Gaseous Emissions Reduction of Firewood-Fueled Low Power Fireplaces by a Gas Sensor Based Advanced Combustion Airflow Control System and Catalytic Post-Oxidation

Zhang,

Ojha,

Bichlmaier

et al. 2023

Sensors

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In view of the tremendous emissions of toxic gases and particulate matter (PM) by low-power firewood-fueled fireplaces, there is an urgent need for effective measures to lower emissions to keep this renewable and economical source for private home heating available in the future. For this purpose, an advanced combustion air control system was developed and tested on a commercial fireplace (HKD7, Bunner GmbH, Eggenfelden, Germany), complemented with a commercial oxidation catalyst (EmTechEngineering GmbH, Leipzig, Germany) placed in the post-combustion zone. Combustion air stream control of the wood-log charge combustion was realized by five different control algorithms to describe all situations of combustion properly. These control algorithms are based on the signals of commercial sensors representing catalyst temperature (thermocouple), residual oxygen concentration (LSU 4.9, Bosch GmbH, Gerlingen, Germany) and CO/HC-content in the exhaust (LH-sensor, Lamtec Mess- und Regeltechnik für Feuerungen GmbH & Co. KG, Walldorf (Germany)). The actual flows of the combustion air streams, as calculated for the primary and secondary combustion zone, are adjusted by motor-driven shutters and commercial air mass flow sensors (HFM7, Bosch GmbH, Gerlingen, Germany) in separate feedback control loops. For the first time, the residual CO/HC-content (CO, methane, formaldehyde, etc.) in the flue gas is in-situ monitored with a long-term stable AuPt/YSZ/Pt mixed potential high-temperature gas sensor, which allows continuous estimation of the flue gas quality with an accuracy of about ±10%. This parameter is not only an essential input for advanced combustion air stream control but also provides monitoring of the actual combustion quality and logging of this value over a whole heating period. By many firing experiments in the laboratory and by field tests over four months, it could be demonstrated that with this long-term stable and advanced automated firing system, depression of the gaseous emissions by about 90% related to manually operated fireplaces without catalyst could be achieved. In addition, preliminary investigations at a firing appliance complemented by an electrostatic precipitator yielded PM emission depression between 70% and 90%, depending on the firewood load.

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Section: Methods Of Sensor-based Air Stream Control For Optimization ...mentioning

confidence: 99%

Extensive Gaseous Emissions Reduction of Firewood-Fueled Low Power Fireplaces by a Gas Sensor Based Advanced Combustion Airflow Control System and Catalytic Post-Oxidation

Zhang,

Ojha,

Bichlmaier

et al. 2023

Sensors

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“…Especially sensors based on a ceramic substrate have proven to be robust in this case of application [55]. To ensure the simple and cost-effective manufacture of the sensors, all layers were applied to a planar substrate using thick-film technology [56,57]. The schematic structure of the sensor is shown as an example in Figure 1.…”

Section: General Sensor Setupmentioning

confidence: 99%

Capacitive, Highly Selective Zeolite-Based Ammonia Sensor for Flue Gas Applications

et al. 2023

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The selective detection of different gas components will remain of huge importance in the future, either in the ambient air or in flue gases, e.g., for controlling purposes of combustion processes. The focus here is on the development of a highly selective ammonia sensor that will be exemplarily used in the flue gas of biomass combustion plants with catalysts for nitrogen oxide reduction. Such applications require a robust sensor design, in this case, based on a ceramic substrate. The gaseous ammonia is detected with the help of a zeolite film, whose selective adsorption properties towards ammonia are already intensively being used in the field of flue gas catalysis. The adsorption and desorption of ammonia on the gas-sensitive zeolite film lead to changes in the dielectric properties of the functional material. Using an interdigital electrode (IDE) structure below the zeolite film, the capacitance was determined as a measure of the ammonia concentration in the gas. In this context, the fabrication of all layers of the sensor in the thick film with subsequent laser patterning of the IDE structure enables a cost-efficient and effective method. The functionality of this sensor principle was extensively tested during measurements in the laboratory. A high and fast response to ammonia was detected at different sensor temperatures. In addition, very low cross-sensitivities to other gas components such as water (very low) and oxygen (zero) were found.

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“…The control of combustion processes in metallurgical and cement furnaces, as well as in boiler units of thermal power plants is an important issue, since the selection of optimization mode of fuel combustion requires data on oxygen concentration and products content for incomplete combustion of fuels in the exhaust gases in real time [1][2][3].…”

Section: Introductionmentioning

confidence: 99%

“…Coal, gas, or oil are the most common fuels used in stove burners. For optimum combustion, oxygen excess and fuel must be minimized [3][4][5].…”

Section: Introductionmentioning

confidence: 99%

Sensor for operational control of oxygen and combustible gases concentration in waste gases of thermal units

Kalyakin,

Volkov

2023

EM&T

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A new sensor has been developed for continuous monitoring of oxygen and combustible gases content in the waste gases of thermal units. The target application of the sensor is its installation in shunt pipes of thermal units, directly into the waste gas flow. The sensor is characterized by one reference gas electrode and three measuring electrodes applied on the surface of a solid electrolyte tube made of a zirconia electrolyte (e.g., 8YSZ). The reference gas electrode and one of the measuring electrodes were made of silver, the second measuring electrode was made of platinum, the third measuring electrode was made of a mixture of zinc oxide (95 wt %) and lanthanum-strontium manganite (5 wt %). The oxygen content in the gas mixture was determined by the well-known potentiometric method in accordance with the Nernst equation, i.e. an Ag|8YSZ|Ag electrochemical cell was used. To determine the products of incomplete combustion of fuel, the method of mixed potential between Pt- and Zn-based electrodes was used; the obtained potential value was determined by the difference in the oxidation rate of carbon monoxide as the main component of unburned fuels, on different materials of measuring electrodes. The experimental results of the sensor for the determination of carbon monoxide, hydrogen, and methane in a gas mixture are presented.

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Application of a Robust Thermoelectric Gas Sensor in Firewood Combustion Exhausts

Cited by 5 publications

References 24 publications

Extensive Gaseous Emissions Reduction of Firewood-Fueled Low Power Fireplaces by a Gas Sensor Based Advanced Combustion Airflow Control System and Catalytic Post-Oxidation

Extensive Gaseous Emissions Reduction of Firewood-Fueled Low Power Fireplaces by a Gas Sensor Based Advanced Combustion Airflow Control System and Catalytic Post-Oxidation

Capacitive, Highly Selective Zeolite-Based Ammonia Sensor for Flue Gas Applications

Sensor for operational control of oxygen and combustible gases concentration in waste gases of thermal units

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