Should a plate tower or a packed tower be used for the quench tower in sulfur recovery?

We are using a packed tower; it hasn’t been put into operation yet, so it’s unclear whether clogging will occur.

We use packed towers, and we have never encountered any problems with clogging. I believe whether blockage occurs has little to do with the type of tower structure, and is mainly related to whether the equipment upstream is operating smoothly.

We also use packed towers, and the pressure drop in packed towers is lower compared to that in plate towers.

As long as the previous processes are stable, the quench tower will function properly. Otherwise, no tower will work.

We used a packed tower and added a filter, which solved all our concerns

We also use packed towers, and this kind of blockage of the tray sheets generally does not occur, as there is already very little acidic gas by the time it reaches the exhaust gas treatment section; moreover, the hydrogenation reaction produces very little sulfur. . . . . .

We are using a packed tower, and operations have not yet started.

Comparison between plate towers and packed towers: For many counter-current contact processes, both packed towers and plate towers can be used. Different tower types have their own advantages and disadvantages, and a choice should be made based on a comprehensive consideration of the system in question. ⑴ The operating range of a packed tower is limited, and it is particularly sensitive to changes in the liquid load. ⑵ Packed towers are not suitable for treating materials that are prone to polymerization or contain solid suspensions. ⑶ Packed towers are not suitable when cooling is required during the gas-liquid contact process to remove reaction heat or heat of solution. Furthermore, when there is a side-line discharge, packed towers are also less convenient than plate towers. ⑷ The diameter of a packed tower can be very small, but the diameter of a plate tower is generally not less than 0.6 m. ⑸ Design data for plate towers is more readily available and more reliable, allowing for smaller safety factors. ⑹ When the tower diameter is not very large, the cost of a packed tower is low.

We have been using the packed tower for 8 years without any blockages!

Structure of plate towers: Although there are various types of trays used in plate towers, their overall structure basically consists of tray plates, mass transfer elements (floating valves, bubble caps, etc.), overflow devices, and connecting components. If a tray consists of only one tray plate, it is called a monoblock tray; if it is made up of two or more tray plates, it is called a segmented tray. Based on the flow pattern of the liquid over the tray, there are single overflow, double overflow, triple overflow, and U-shaped flow, among which single overflow and double overflow are the most common. The selection of the flow pattern is basically determined based on the tower load; while meeting the process requirements, attention must also be paid to the stiffness of the tray connections as well as ease of installation and maintenance. Tower accessories also include demisters and anti-vortex devices. The demister is installed at the top of the tower; its function is to separate the liquid droplets entrained in the gas at the tower top. The foam eliminators currently in use include plate-type, mesh-type, and swirl-type ones, among which the mesh-type is the most widely used. Screen foam eliminators have advantages such as a large specific surface area, light weight, large pores for easy use, high foam elimination efficiency, and low pressure drop. Suitable for cleaning gases; not suitable for use in situations where the droplets contain solid substances or are prone to precipitating solids. When the liquid at the bottom of the tower flows out, if it contains vortices, these can draw gas into the pump, leading to problems such as pump cavitation; therefore, an anti-vortex device is installed at the bottom of the tower. When the diameter of the drain pipe is less than 150 mm, a steel plate is welded at the pipe opening; when the diameter is greater than 150 mm, a cross-shaped plate is welded at the pipe opening. The drain pipe can extend a certain distance into the bottom of the tower to prevent impurities, sediment, or small internal components within the tower from being drawn into the pump. The quench tower that uses a packed tower is also a commonly used gas-liquid mass transfer device in petroleum refining and chemical manufacturing processes; some exhaust gas treatment systems in China employ packed towers in exhaust gas quench towers and absorption towers as well. Compared with plate towers, packed towers have advantages such as a simple structure, low pressure drop, and the ability to use corrosion-resistant materials for the packing. However, the installation, cleaning, and maintenance of fillers are rather troublesome, and they have poor adaptability to materials containing solid impurities, those prone to coking, or those prone to polymerization. In practical applications, there is no absolute standard for choosing which type of tower to use; factors such as the properties of the material, operating conditions, and economic considerations are often taken into account when making a decision. Table 1 shows a comparison of the performance of plate towers and packed towers. Table 1 Performance comparison of plate towers and packed towers
| Parameter | Tower type | Plate tower | Packed tower |
|-----------|-------------|-------------|---------------|
| Pressure drop | – | Generally higher than that of packed towers | Lower pressure drop; more suitable for applications requiring low pressure drops |
| Empty-tower gas velocity (production capacity) | Higher | Lower | – |
| Tower efficiency | Relatively stable; efficiency is higher for larger plates | – | Efficiency is generally high for tower diameters below φ1500 mm; it tends to decrease as the diameter increases |
| Liquid-to-gas ratio | Wide range of adaptability | Certain requirements regarding the amount of liquid sprayed | – |
| Liquid holding capacity | Higher | Lower | – |
| Material requirements | Usually made of metal materials | Non-metallic corrosion-resistant materials can also be used | – |
| Installation and maintenance | Easier | More difficult | – |
| Cost | Generally lower than packed towers when the diameter is large | Generally cheaper than plate towers for diameters below φ800 mm; cost increases significantly as the diameter grows | – |
| Weight | Lighter | Heavier | – |

There are many types of packing, which can be broadly classified into two categories based on their packing method: granular packing and structured packing. Due to their structural characteristics, granular fillers can only be piled freely, which is why they are also referred to as \"randomly piled\" fillers. Common granular packing materials include Raschig rings, Böhlke rings, cross rings, θ-rings, arc-shaped saddles, rectangular saddles, etc. The gas-liquid distribution of this packing is not uniform enough, resulting in less than ideal separation performance of the tower. To this end, structured packing was developed; it offers good separation performance and low pressure drop, making it suitable for operation at high gas velocities or with low reflux ratios. Currently, corrugated mesh packing and corrugated plate packing are the main types used. A packing material is a solid filler whose role is to provide a sufficient contact surface between the gas and liquid phases, as well as to create conditions that enhance turbulence for better mass transfer. Therefore, the efficiency of a packed tower is highly dependent on the packing material used. Generally, the following requirements are placed on fillers: (1) The porosity (also known as free volume) should be high. That is, the volume of voids per unit volume of the packing layer should be large. (2) The specific surface area should be large. That is, the surface area per unit volume of the packing layer should be large. (3) The filler should have good surface wettability, and its structure should facilitate close contact between the two phases to promote turbulence. (4) It exhibits good corrosion resistance against the materials being processed. (5) The careful construction of the filler itself (in terms of both material and structure) should result in a compact form, along with sufficient mechanical strength. (6) It is easy to obtain materials, convenient to manufacture, and inexpensive. At the top of the packed tower, a liquid distribution device is installed above the uppermost packing layer, in order to ensure even distribution of the liquid over the packing and facilitate thorough contact between the gas and liquid phases. Since the upward velocity of the gas through the packing layer is unevenly distributed across the cross-section of the tower – with higher velocities in the center and lower velocities near the wall – this has a different effect on the liquid flowing downstream. As a result, the liquid tends to flow toward the wall as it passes through the packing layer; this phenomenon is known as \"wall flow\". The liquid distribution device can reduce or even eliminate the occurrence of wall flow. Whether the tower gets blocked depends on the operations at the front, not on its structural design. This post was last edited by adsl121 on 2009-4-4 21:31]

Our new unit uses a packed tower; we haven’t taken any risks with that. The old unit was a plate tower with high pressure drop, so an on-line booster was used, which resulted in high costs.

The plate tower we use in our facility has been in use for 4 years; it has experienced blockages, but those issues were resolved quickly.

It is better to use a packed tower; the pressure drop in such a tower is low. Generally, the exhaust gas after rapid cooling is directly fed into the exhaust gas incinerator after being absorbed by a solution. If the pressure drop in a plate tower is high, it will result in high pressure in the sulfur production furnace, and intermediate pressurization may be required to meet the process requirements. This results in many devices in the process and complex procedures. Our factory uses packed towers, and no clogging has occurred after 3 years of operation.

Now, most manufacturers choose packed towers, using structured packing. The performance is similar to that of a plate tower, with lower pressure drop; thus, no additional power equipment is required after entering the absorption stage. Active participation

It depends on the processing capacity of your facility. For large sulfur processing plants, it is not suitable to use packed towers in the quench towers; packed towers may lead to flow deviation due to their large diameter, and they are also more expensive. It is necessary to calculate based on the processing capacity of your facility to determine whether packed towers can fulfill the cooling requirements. It is recommended to use a tray tower

It depends on the processing capacity and the diameter of the tower to be chosen, in order to determine whether it should be a plate tower or a packed tower

Bauer rings are being used; they were cleaned once some time ago, and part of the packing was replaced. A filter is installed at the bottom of the tower; water circulation in the quench tower is filtered

A 70,000 tons/year sulfur production unit with a packed tower has been in operation for four years and is in good condition, with no signs of blockage! The reasons for blockage in the packed tower are as follows: 1. Fluctuations in the unit’s operation allow sulfur particles to get inside, causing blockages; 2. The quench water is not replaced on a regular basis, and when there are fluctuations in the unit’s operation, the water quality becomes poor.

Our new unit uses a packed tower, which has its own advantages and disadvantages. Plate towers are less prone to clogging, but they have a higher pressure drop, while packed towers have a lower pressure drop; however, they are more likely to get clogged during operation. The key still lies in the operations carried out earlier – as long as those are done properly, clogging will not occur later on.