Atomization of water-coal slurry gasification burners

The issue of the gasification angle in water-coal slurry gasification is actually something that can be anticipated; the formation of the gasification angle in water-coal slurry burners is determined by the cutting rate of oxygen on the water-coal slurry. When the oxygen cutting rate is high, the angle becomes larger (with the shape of the burner remaining unchanged), and this leads to better dispersion and more complete reactions. If the atomization angle is too small, the amount of water-coal slurry decreases, resulting in incomplete reactions; this in turn causes an excess of oxygen in the upper part of the space, leading to a reaction between oxygen and CO and an increase in temperature there.

After reading it several times, I keep feeling that the explanation on the second floor seems a bit forced: L

The impact of the atomization angle size on temperature depends on certain underlying conditions. When the flow rate remains constant, a smaller atomization angle results in a higher local flow rate, which prolongs the time required for combustion; as a result, the high-temperature zone moves upward.

I think to determine whether the temperature is higher in the upper or lower part of the furnace, it mainly depends on where the exothermic reactions such as combustion take place

Whether the high-temperature zone moves upward depends on the ratio of oxygen to slurry flow rate, as well as on the slurry concentration, particle size, viscosity, and the degree of uniform mixing of coal and oxygen

The upward movement of the high-temperature zone in the furnace is related not only to the atomization angle of the gasification burner, but also to factors such as the amount of coal slurry, the load, and the length-to-diameter ratio of the furnace. There are also certain differences between the burners of Texaco furnaces and those of multi-nozzle furnaces.

I still don’t understand; with all other factors remaining constant, how can a too-small atomization angle cause the high-temperature zone to move upward?

It’s not only far-fetched but also seems to contain some errors. \"If the atomization angle is too small, it will reduce the amount of water-coal slurry, resulting in insufficient reaction; this leads to an excess of oxygen in the upper area, causing a reaction between oxygen and CO and raising the temperature there.\" A small atomization angle merely indicates poor atomization performance, and it does not cause a decrease in the flow rate of the coal slurry; however, it can shorten the flame length, which means that the combustion zone moves upward, and as a result, the temperature in the upper part of the furnace is higher.

A decrease in the atomization angle should result in the flame being elongated, which in turn should cause the high-temperature zone to move downward. (Personal opinion)

Agree with the opinion from floor 11. The size of the atomization angle is independent of the slurry flow rate. With a larger atomization angle, the flame shortens, and the entire gasification and combustion reaction moves upward; as a result, the high-temperature zone also moves upward. Conversely, the high-temperature zone should move downward. This post was last edited by Langtaosha on 2008-6-14 12:09.]

Agree with the opinion from floor 11. I believe that in actual production, the size of the atomization angle has little impact on the atomization effect (of course, an excessively small angle does have a significant impact). What matters most is whether the high-speed gas-solid flow will directly erode the inner layer of refractory bricks; in practical production, the main concern is to prevent the atomization angle from being too large. If the atomization angle is too small, a large amount of slurry will be blown toward the lower part of the combustion chamber (lengthening the flame), resulting in an increase in temperature in that lower area.

First, it is necessary to determine the impact of the atomization angle on the atomization effect of water-coal slurry. Experiments show that either too large or too small an atomization degree is not ideal; there is an optimal range. While considering the atomization effect, it is also necessary to think about choosing an appropriate size for the furnace. As the angle changes, the jet intensity (range and flame strength) also changes. Moreover, when the atomization angle remains the same, the selection of nozzle size is another factor to consider.

Agree with what was said on floor 11. Texaco’s burners are similar to the nozzles used in gas cutting: they have a low oxygen content at the center, which results in a longer flame but poor flame stability.

I have never seen what a gasification furnace system looks like, but based on my experience with spray drying systems, I would like to share some of my thoughts. When the flow rate remains constant and the atomization angle decreases, the material processing density per unit volume increases. Meanwhile, the amount of material that can be processed per unit volume, or the amount of drying that can take place, as well as the amount of oxygen supplied for combustion, stays constant. As a result, the material that could previously be dried or burned becomes compressed due to the smaller atomization angle; it cannot be processed quickly enough, so more time is required or a larger space is needed to carry out the processing. Therefore, I speculate that this is probably the reason why the temperature of the gasification furnace has risen.

From a technical perspective, I will analyze this issue: the atomization angle is a key factor in the design of burners, and the efficiency with which a burner can atomize coal slurry is also an indicator of its quality. 1. A small atomization angle results in poorer physical and chemical properties; the flame becomes shorter, there is an excess of oxygen at the tip of the burner, and the components that undergo combustion reactions to produce CO2 increase. As a result, the temperature in the area near the burner tip rises, and the high-temperature zone moves upward as well. 2. With a small atomization angle, the burner opening is small as well, resulting in uneven contact between oxygen and carbon; in other words, oxygen and carbon do not flow into the reaction zone uniformly. As a result, some of the carbon is completely burned in the area at the burner outlet, causing the temperature zone to rise accordingly. 3. The atomization angle should have a standard range of values; it shouldn’t vary greatly. The atomization angle is too large, resulting in poor physical and chemical effects ； The particle size is too small, resulting in excellent materialization effects; however, it is not suitable for water-coal slurry gasification as it can cause sparks to fly, which is detrimental to refractory materials. If there are any mistakes, please feel free to point them out! This post was last edited by GSP on 2008-12-5 11:15]

Well, it seems like this explanation is quite plausible