The acid production system has a large processing capacity, but the actual volume of gas it can process is small – what problems might arise from this?

Firstly, it has high energy consumption; secondly, its purification effect may be poor

I disagree a bit with the guy upstairs; it’s true that energy consumption is high, but the purification efficiency won’t be poor. Moreover, since the equipment can have a capacity greater than its actual capacity, the efficiency might even be better. The same is true for dry absorption, but it could lead to instability in the thermal balance during the conversion process. It's just my personal opinion; please correct me if I'm wrong.

The purification effect may deteriorate due to insufficient gas flow, but the change is not significant. After the system load decreases, the amount of flue gas and ash also reduces. However, there are serious problems with the conversion system; heat balance is a major issue. Moreover, because the system load is too low, many devices may operate below their dew point, so corrosion issues need to be taken into consideration

It’s true that energy consumption is high, but I’m not too convinced by the claim that the purification efficiency decreases; it probably depends on how low the air volume is, as well as what type of purification equipment is used. The heat balance during transformation should fluctuate; I haven’t done the detailed calculations, so it’s hard to say for sure.

The heat balance during conversion should be affected; the temperature difference in the heat exchanger changes, resulting in an increase in the temperature of the SO2 gas and a significant decrease in the temperature of the SO3 gas. The extent to which this affects production depends on whether there are adjustment bypasses available and on the capacity of those bypasses for adjustment.

So, may I ask everyone, what problems can arise with too low a gas velocity for converters?

If the reduction in production is minor, self-balancing can be achieved by adjusting the auxiliary valves. However, as the person mentioned, it’s less clear how to achieve a halving of the load. I seem to have heard before that there was a case where thermal balance couldn’t be maintained, with temperatures in all sections dropping significantly, forcing the use of electric furnaces for heating. . . The circulation rate of the purification system needs to be adjusted. A lower gas velocity in the empty tower can lead to insufficient gas-liquid contact, resulting in leakage and other issues; however, the impact should be moderate. The dry absorption section is hardly affected by this. Additionally, the energy consumption per ton of acid will definitely increase. For the converter, a lower gas velocity reduces the bed resistance, but it also causes uneven distribution of the gas phase (laterally). These are just my personal opinions; I welcome corrections from those with more expertise

Regarding heat exchangers, my personal opinion is as follows: when the gas flow rate is low, the flue gas velocity is also low, which results in a decrease in the convective heat transfer coefficient; accordingly, the overall heat transfer coefficient also decreases. Even though the surface area increases, the total heat transfer amount should not differ much.

Wire mesh mist eliminators are generally used in drying towers; when the gas flow rate is low, the mist elimination efficiency decreases accordingly.

The overall system resistance should have decreased, right?