1.Q: Can you please explain why the zirconia probe is easily damaged when restarting after the generator unit is shut down? Do you know if your company's zirconia probe also has this problem?
Answer: The direct reason why zirconia is easily damaged when restarting after shutdown is because the water vapor in the flue gas condenses and remains in the zirconia head after shutdown. If the heating furnace of the zirconia probe is reheated, it is easy to damage the ceramic zirconia head. As is well known, zirconia heads should not touch water during heating. Because the NOVATECH zirconia probe has undergone special treatment in its structure, there is no damage caused by restarting after shutdown.
2. Q: Generally, the service life of domestic zirconia probes is relatively short, while foreign products seem to be relatively long, but usually only about 1 year. How long can your company use zirconia probes?
Answer: NOVATECH's zirconia probe has been used in dozens of home appliance factories and dozens of steel mills in China, among others. The average service life in petrochemical plants is 4-5 years. It took 10 years for the zirconia probe installed in a certain power plant and 1998 to be scrapped and replaced. Of course, in different power plants, different operating conditions are closely related to the quality and reasonable use of coal powder.
3. Q: Due to the large amount of dust in the flue gas, the zirconia probe is often blocked, and it is often found that using compressed air for online blowing can damage the zirconia head. In addition, many zirconia probe manufacturers also have regulations on the gas flow rate of the standard gas during on-site calibration. If the gas flow rate is too high, it can also damage the zirconia head. May I ask if your company's zirconia probe also has such problems?
Answer: When using standard gas, it is important to pay attention to the flow rate of the standard gas, as the flow rate of the standard gas can cause a local temperature drop in the zirconium head, resulting in calibration errors. Due to the possibility of poor control during calibration, excessive oxygen flow rate in the compressed cylinder may occur. In addition, similar situations may occur when using compressed air for online blowing, especially when compressed air generally contains water. The temperature of the zirconia head during operation is around 600-750 degrees, and at this temperature, the ceramic zirconia head is very fragile and easily damaged. Once local temperature changes or encounters water, cracks will immediately occur in the zirconia head, which is the direct cause of zirconia head damage. However, the structure of NOVATECH's zirconia probe is different from that of ordinary zirconia probes. It can be directly blown online with compressed air and has a high standard gas flow rate without damaging the zirconium head. I have demonstrated that even if a zirconia probe heated to 720C is directly placed in water, it can still function normally. This technology is currently at the forefront of the industry.
4. Q: Generally, due to the limited length of the zirconia probe, one zirconia probe is installed on each side of the flue to ensure accurate measurement. However, due to the high price of imported oxygen analyzers, one zirconia probe is installed on each side of the flue. Can a longer zirconia probe be used instead of two shorter zirconia probes?
Answer: Due to the fact that the diameter of the flue in general power plants is 8-10 meters, and large flue ducts can cause vibration. If the length of the probe is too long, the zirconia head is very fragile at high temperatures (because the operating temperature of the zirconia head cannot be lower than 600C, the zirconia probe used in power plants is equipped with a heating furnace). Therefore, an extended probe (usually not exceeding 2 meters) is easily damaged, And as the length of the probe increases, the price will also increase. NOVATECH's oxygen analyzer can come with two zirconia probes per instrument, making it more cost-effective.
5. Q: Because the water vapor in the flue of the power plant is relatively high, about 30%, the zirconia probe installed near the economizer often breaks, especially when the water pipe near the economizer bursts. What is the reason for the zirconia probe damage?
Answer: Because any ceramic material is very fragile at high temperatures, the biggest fear is that when the zirconium head encounters water at high temperatures, the zirconia will undoubtedly be damaged. Imagine what happens when a ceramic cup with a temperature of around 700 degrees Celsius is placed in water? But NOVATECH's zirconia probe can indeed make such an attempt. Of course, we do not encourage customers to conduct such tests, but it does indicate that NOATECH's zirconia probe has strong water resistance at high temperatures. This is also the direct reason why NOVATECH's zirconia probe has a relatively long service life.
6. Q: Why are zirconia probes used in garbage incineration power plants particularly prone to damage, especially when the metal outer casing of the probe decays severely? How long can NOVATECH zirconia probes with heaters be used in general?
Answer: Burning urban waste to generate electricity is the most scientific and energy-saving treatment method. However, due to the complex composition of waste, environmental pollution has a higher oxygen content in the combustion process compared to ordinary coal or oil fired boilers to ensure its full combustion and emission of smoke. Increase the acidic components in the flue gas. In addition, there are various acidic substances and water in the garbage, which will produce a highly corrosive hydrofluoric acid after the garbage is burned. If the zirconia probe is installed in a position with a relatively low ambient temperature (300-400C) in the flue, the stainless steel outer sleeve of the probe will decay in a short period of time. In addition, the water in the flue gas is also easy to remain at the zirconia head and damage the zirconia head. As an example, Tianjin Teda Waste Incineration Power Plant is a waste incineration power plant that was built earlier and has a relatively large installed capacity in China. In order to compare the performance of zirconia probes, NOVATECH and two other foreign companies installed zirconia probes in 2005. As a result, the zirconia probes of the other two companies were only used for a few months and could no longer be used. All of them had to be replaced with NOVATECH products. The NOVATECH zirconia probe, which was first installed in 2005, is still in normal use until 2009.
7. Q: Due to the high furnace temperature and high precision of micro oxygen measurement in the metal powder sintering furnace, our company has tried products from several domestic and foreign companies that cannot meet the measurement requirements. I wonder if NOVATECH's zirconia probe can be used for oxygen measurement in the metal powder sintering furnace?
Answer: NOVATECH's zirconia probe can be used for oxygen measurement in various occasions. Its inline zirconia probe can be used for measuring the highest furnace temperature of 1400C degrees, and the lowest oxygen content can be measured to the minus 30th power of 10 (0.000 000000 000000 000000 1%). The largest metal powder product in China was originally installed by Dongmu Group with a German zirconia probe, but it did not work after 1-2 months of use. Later, other companies' zirconia probes also failed, Finally, NOVATECH's zirconia probes were used to meet the design requirements in all aspects on the six muffle vacuum furnaces currently in use. Dongmu Group has prepared to install NOVATECH's zirconia probes in all places where they are required.
8. Q: The zirconia probe can quickly measure the standard gas value when measuring. Why does it take a long time to measure the actual oxygen content in the flue, especially when the standard gas port is opened and then closed, when the oxygen probe returns from 21% ambient oxygen to the oxygen content in the flue for a long time. It is difficult to discuss the principle of control to control the oxygen content after combustion. Is the same true of NOVATECH's zirconia probe?
Answer: Generally, the instructions for zirconia probes indicate that zirconia probes can measure the actual oxygen content in only 4-10 seconds. However, most zirconia probes only have a flat filter, and the zirconia head is still some distance from the flat filter. When using standard gas, the pressure in the standard gas cylinder quickly sends the standard gas to the zirconia head, and of course, the standard gas value can be measured immediately. However, in actual measurement, whenever the oxygen content in the flue changes, the oxygen content after the change takes a relatively long time to replace the oxygen content at the original zirconia head. For example, from the original 21% ambient oxygen to the actual oxygen content in the flue. So the actual measurement time required should be the actual measurement speed by closing the standard gas hole and restoring the oxygen probe to the oxygen content value before the standard gas. Users can easily conduct an experiment to calibrate the zirconia probe with 2-4% oxygen in the ambient air at 21% oxygen content. Immediately close the calibration port and observe the time required for the oxygen probe to return to 21% ambient air oxygen. Generally, zirconia probes with flat filters usually take 15-20 minutes. NOVATECH's zirconia probe is equipped with two filters, forming a circulating airflow field with gas flow at the zirconia head, accelerating the replacement of the oxygen content at the original zirconia head, and allowing for the actual measurement value to be obtained in a very short period of time.
9. Q: Why does a typical zirconia probe require the 2-point calibration method to calibrate the zirconia probe before it can function properly?
Answer: As we all know, the measurement principle of zirconia probes is designed based on the Snet measurement formula, which is quite difficult to achieve due to actual material and processing requirements. In this way, most zirconia probe production companies can only produce zirconia probes that indirectly comply with the Snite measurement formula, and this type of zirconia probe needs to be calibrated with a 2-point standard gas to work properly. However, because the Snite measurement formula is a curve, even if calibrated with a 2-point standard gas, there will still be measurement errors, and the values of the 2-point standard gas cannot differ significantly, and can only be between 6-8% oxygen content. So in the past, power plants mainly measured the oxygen content below 10% in the flue gas. But modern power plants need to control the oxygen content in the flue during ignition for both energy-saving and environmental reasons The usual measurement range for oxygen content is from 1.0 to 20.0%. Most zirconia probes calibrated using the 2-point calibration method cannot be calibrated within this relatively large range. This will inevitably cause errors in the measurement. NOVATECH's zirconia probe is produced entirely based on the principle of the Snite measurement formula, which ensures a wide range of measurement standards. Normally, only ambient air calibration is required, which greatly facilitates user use and saves the cost of standard gas cylinders. To ensure the accuracy of measurement, users can use any range of standard gas to test the measurement accuracy of NOVATECH's zirconia probe.
