Can water be sprayed on the regenerative flue gas pipeline for cooling?
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Can water be sprayed on the regenerative flue gas pipeline for cooling? Can it be completely vaporized in a short time? What are your experiences with its performance? What are the hazards of spraying water on the regenerated flue gas?
Many devices exist, but very few are actually in use; in fact, they cause more damage to the equipment than they help protect it!
The atomization effect of the nozzle is crucial.
Many designs exist; the earliest ones were located between the first and second stage centrifuges. It is mainly for protecting the equipment when it overheats. But many have become clogged due to lack of use over time. I don’t have much experience using it, but I used it quite a lot in the past; I remember that there’s an entrance with three spindles and also a water spray point. It’s likely not good for the lining, but it won’t cause the lining to come off; the water will vaporize as soon as it gets in.
They are included in the design, but have never been used; over time they get clogged. The main reason for not using them is to take into account the long-term operation of the exhaust fan.
The old unit was originally equipped with lean-phase and flue water/steam injection systems; I can’t remember whether they were ever used. These systems were removed during the unit’s renovation. However, a new catalytic unit with a capacity of 2.9 million tons that was put into operation in recent years is also equipped with flue water/steam injection systems.
Our unit isn’t designed with such a feature; I think that when the equipment overheats severely, steam or water can be sprayed in, but care should be taken regarding the amount sprayed to avoid large fluctuations in operating pressure.
Based on the analyses of the various posters above, many devices have them, but few are actually used. I think the reasons are as follows: 1. The actual spraying effect is not ideal; that is, it is not possible to turn water into very small droplets. 2. Due to the large difference in specific heat between water and flue gas, a small amount of water to be vaporized requires a large volume of flue gas. 3. Due to the high velocity of the flue gas, some larger-diameter water droplets are carried by the fast-moving gas flow to downstream equipment, where they rapidly vaporize.
The water and steam injection for the regenerated flue gas is generally arranged between the vertical section exiting from the flue gas collection duct and the inlet to the three-spinners. The water and steam are not injected directly at the lining; instead, there is a liner plate at the position corresponding to the nozzles, made of stainless steel. This liner plate has a shape similar to that of an angle iron and occupies the entire length of this section of the flue duct. In this way, when water or steam is injected, it first hits the high-temperature liner plate, where it vaporizes rapidly, thereby achieving a cooling effect. Spraying water or steam into the regenerator flue is now basically not used.
When the flue inlet temperature is too high, it is possible to apply an appropriate amount of paint or water to the flue; spraying water or steam into the regenerator flue is now basically not used.
1 In previous designs, there were measures of spraying water through smoke pipes, but these were rarely used, and some designs have removed such measures. 2 Short-term overheating is permissible, but prolonged operation poses a safety risk; it is necessary to avoid residual combustion of flue gas during regenerator operation by making adjustments, such as adding oxidizing agents.