In recent years, a large number of cities in northern China have been shrouded in haze weather. The direct cause of this haze weather is the emission of a large amount of flue gas from coal-fired heating boilers in the north. Because coal-fired heating boilers have old air leakage and no follow-up dust removal equipment, a large number of sulfur-containing dust particles are discharged into the atmosphere with the flue, causing environmental pollution and damage to the human respiratory system. Due to the cold weather in the north, a large amount of acidic dust cannot spread to the upper air, so it gathers in the low pressure layer to form a turbid haze air. With the country’s gradual emphasis on air pollution control and the application of various new technologies, a large number of old coal-fired heating boilers are being transformed into gas-fired boilers that use natural gas as fuel.
Since gas-fired boilers are dominated by automatic control, the control of oxygen content in combustion is relatively high. Because the level of oxygen content directly affects the size of gas consumption, for heating enterprises, controlling aerobic content is direct and economical. benefit related. Moreover, since the combustion method of gas boilers is different from that of coal-fired boilers, the composition of natural gas is methane (CH4), which will generate a large amount of water after combustion, and the flue will be filled with water vapor.
2CH4 (ignition) + 4O2 (combustion support) → CO (involved in combustion) + CO2 + 4H2O + O2 (weak free molecules)
Because a lot of water in the flue gas will condense at the root of the oxygen probe, the dew will flow along the wall of the probe to the head of the probe, because the head of the oxygen probe works at high temperature, when the dew comes into contact with the high-temperature zirconium tube water Instantaneous gasification, at this time, the amount of oxygen will fluctuate, resulting in irregular changes in the amount of oxygen detected. At the same time, due to the contact of dew and high temperature zirconium tube, the zirconium tube will burst and leak and damage. Due to the high moisture content in the flue gas of gas boilers, the oxygen content is generally measured by taking the flue gas out to cool down and filter out the moisture. From the perspective of practical application, the method of air extraction, cooling and water filtration is no longer a direct-insertion method. It is well known that the oxygen content in the flue gas has a direct relationship with the temperature. The oxygen content measured after cooling down is not the real oxygen content in the flue, but an approximation.
An overview of the differences and characteristics of flue gas after combustion of coal-fired boilers and gas-fired boilers. For this special oxygen measurement field, our R&D department has recently developed a zirconia probe with its own water absorption function, with a water absorption capacity of 99.8%. residual oxygen. It can be widely used in gas boiler flue oxygen measurement and monitoring of desulfurization and denitrification equipment. The probe has the characteristics of moisture resistance, high precision, easy maintenance and long life. After the whole year of field certification application in 2013, all performance indicators meet the design requirements. The probe can be widely used in high moisture and high acid environments, and is the only in-line probe in the field of oxygen measurement.
The water-absorbing zirconia probe for Nernst gas boiler can be matched with any other brands of oxygen analyzers at home and abroad, and has strong general performance.
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Post time: Mar-31-2022