How significant is a saturated hot water tower really?

1. The saturated hot water tower is the main device used by the heat recovery system; if the issue of equipment corrosion can be resolved, it is necessary to install a saturated hot water tower； 2. For systems with a high conversion rate (such as those where the gas CO value is less than 2.0), due to the large amount of vapor, a saturated hot water tower can recover more heat, resulting in significant energy savings from its use ； 3. For systems with a low conversion rate (such as when the conversion gas CO is greater than 4.0), the amount of heat that can be recovered from a saturated hot water tower is limited; moreover, this may lead to corrosion of the equipment. In such cases, it is possible to omit the saturated hot water tower.

I believe that the saturated tower is primarily used to humidify semi-water gas (the feed gas) in order to save steam. The hot gas recovery system extracts heat from the exhaust gas and transfers it to semi-water gas. In our company’s fully reduced-pressure process, the saturation tower and the moisture at the outlet are prone to corrosion, especially at the dew point. The newly introduced all-low-temperature process retained only the hot water tower, eliminating the saturation tower; no corrosion has occurred in the inlet pipes and equipment over the 4 years since they were put into operation. The current saturated tower process is also set to be converted to a non-saturated tower process in the near future.

The function of a saturated hot water tower is to raise temperature and humidity as well as recover heat from reactions, and I think this is very necessary

The saturated hot water tower is of great significance; it serves to increase the temperature and humidity of the steam at the inlet. For medium- and low-pressure shift processes, if the temperature at the outlet of the saturated tower is high enough, it is possible to achieve zero steam consumption in the shift unit, and it can also be used to recover heat at the outlet of the shifted gas

The main purposes of a saturated tower are two: one is the recovery and reuse of heat, and the other is the utilization of steam. It is explained very thoroughly whether the 2nd floor is actually needed.

It depends on the process; each has its advantages and disadvantages. Another function of the saturated tower is the purification of gases, rather than just recovering a portion of the steam.

The main function of a saturated hot water tower is to recover heat, but as mentioned above, it is prone to corrosion; we have had leaks several times here. It is feasible to remove the saturation tower, but professional design is required for the modification.

Saturated hot water towers are used for heat recovery and humidification, but they have various drawbacks such as corrosion and wastewater discharge; therefore, I wonder if there are other ways to recover heat that would allow for the elimination of saturated hot water towers

In fact, the saturated hot water tower was introduced during medium-temperature shift. At that time, it was mainly because the steam-to-gas ratio in the medium-temperature shift process was relatively high, ranging from 0.7 to 0.8 (referring to the steam ratio to semi-water gas); as a result, there was a significant amount of waste heat in this system, which needed to be recovered using a saturated hot water tower. However, with the advancement of ammonia synthesis technology, the shift process was gradually changed to medium-series low ； Medium-Low-Low ； Until it reached full low variation. As the waste heat in the system decreases, it becomes less economical to use a saturated hot water tower. When it is required that the CO content after conversion be below 2.0%, a relatively large amount of additional steam is needed; in such cases, a saturated hot water tower can still be used to some extent. However, when glycol is present in the system and the CO content after conversion reaches around 7%, very little additional steam is available, and as a result, the heat that can be recovered by the saturated hot water tower is also minimal. Some factories want to get rid of the saturated hot water towers. What we need to compare here is whether the investment cost of a saturated hot water tower is higher, or whether the value of the heat recovered over the entire lifetime of the tower is greater. This allows it to be determined whether a saturated hot water tower is still needed.

If the temperature is high enough, the steam required for conversion can be virtually self-sufficient, with only a small amount of external steam needed. Generally, it doesn’t reach that saturation temperature. Other heat exchange methods are not as efficient as this one. The investment could be substantial.

A saturated hot water tower is primarily used to increase the gas-to-vapor ratio and reduce steam consumption to a certain extent. Under the current economic conditions, it is necessary to consider the economic aspects; should it be retained?

A saturated hot water tower is a heat recovery center; it can also be regarded as a center for free steam generation using gas. What is the free quota? In the case of a full low-temperature shift, the steam-to-ammonia ratio is generally between 0.13 and 0.35, that is, 345 Kg/tNH3 to 928 Kg/tNH3. The amount saved is not much; a plant with a capacity of 100 Kt/a saves between 5.52 million and 14.85 million m³ per year, and there is a reduced investment in utility systems for steam generation capacities of 5 t/h to 13 t/h. But competition is fierce, and that amount of money might be the last straw on a camel’s back. Furthermore, a saturated hot water tower is beneficial for stable production, as the load can be adjusted up or down as needed. Furthermore, the corrosion of saturated hot water towers can now be effectively controlled. There are other methods available for recovering heat for internal use, but they face relatively high obstacles, complex processes, and overly fragmented operations, making them uneconomical. Of course, if the system pressure is above 4.0 MPa, it is estimated that there will be sufficient water vapor carried in by the gas, so there’s no need to worry about this.