What is a spray tower?

Spray tower, also known as spray absorption tower. There are no packing or trays inside the tower, but there are nozzles for the absorption process. The liquid enters from the top of the tower and is sprayed into a mist or droplet form by the nozzles; the gas enters from the bottom of the tower and comes into close contact with the mist or droplet form of the liquid for mass transfer, allowing the soluble components in the gas to be absorbed. The structure is simple, not prone to blockage, has low resistance, and is easy to operate and maintain.

1. Working Principle

The acid mist exhaust gas is introduced into the purification tower through the duct. After passing through the packing layer, the exhaust gas and the sodium hydride absorbent come into full contact with the gas and liquid to absorb and neutralize the gas. After purification, the acid mist exhaust gas is dehydrated by the dust plate and then discharged to the atmosphere by the fan. After being pressurized by the water pump at the bottom of the tower, the absorbent is sprayed from the top of the tower and then recirculated to the bottom of the tower. The purified acid mist exhaust gas meets the national emission standards.

2. Characteristics

(1) The dust removal and desulfurization efficiency is high. When using alkaline washing water, the desulfurization efficiency can reach 85%.

(2) The equipment occupies a small space and is easy to install.

(3) The water and electricity consumption indices are relatively low.

(4) Corrosion-resistant, without wear, and with a long service life.

(5) The equipment operates reliably and is easy to maintain.

3. Structure

A mass transfer device that uses a spray tower packing layer as the contact element for the gas-liquid two-phase mixture. The packing support plate is placed at the bottom of the packing tower, and the packing is arranged in a stacked manner on the support plate. The packing pressure plate is installed above the packing to prevent upward airflow from blowing out. The spray tower sprays liquid from the top of the tower, and the liquid reaches the packing through the liquid distributor and flows downward along the surface of the packing. After the gas is distributed from the bottom of the tower, the liquid flows through the gaps of the packing layer in a countercurrent manner. At the packing surface, the gas and liquid phases closely contact and undergo mass transfer. When the liquid flows along the packing layer, sometimes there is wall flow. The wall flow effect causes the distribution of the gas and liquid phases in the packing layer to be uneven, resulting in a decrease in mass transfer efficiency. Therefore, the packing layer in the spray tower is divided into two parts, and a redistribution device is set in the middle. After redistribution, the liquid is sprayed onto the lower packing.

4. Applicable Conditions and Precautions

(1) Circulating water flow regulation: It is determined by the water supply pump of the spray tower. One pump can be turned on when one boiler is operating. When two or three pumps are running simultaneously in winter, they should all be turned on. The flow of the slurry pump should be adjusted according to the flow that does not allow for circulation. Make it equal.

(2) Dosage of the dosing tank in the spray tower: During the operation of the boiler, 2 bags of alkali and 5 bags of lime are added in winter. If there are two or three sets, the dosage can be increased according to the corresponding quantity.

(3) The spray tower sedimentation tank should be cleaned regularly, once a week. In summer, it should be cleaned once a week; in winter, it should be cleaned once every three days.

(4) When the grey water separator discharges, for each gear shift discharge, the discharge valve should be opened separately until clear water is discharged.

(5) The above rotating components should be inspected frequently, lubricated, and any faults should be promptly addressed to ensure the effectiveness of sulfur removal by the spray tower.

(6) When going up or down the stairs, be careful of your safety and have the awareness of self-protection and mutual safety.

(8) After work, promptly clean up the sanitation facilities so that people can walk on the construction site.

The washing method of the spray tower

The washing spray tower and wet dust collectors all make use of water or other liquids to come into contact with the dusty gas. They utilize liquid screens, liquid films or liquid droplets to capture the dust, thereby purifying the dusty gas.

The water in the washing-type dust collector can be classified into three forms according to the way it comes into contact with the dusty gas.

(1) Water droplets are formed by mechanical spraying or other methods, and then water of different sizes is dispersed into the airflow to become dust-catching bodies.

(2) Water film A water film forms on the dust-capturing surface. The dust in the airflow is attracted to the water film due to factors such as inertia and centrifugal force.

(3) Bubbles: Water and gas come into contact in the form of bubbles. This mainly occurs in foam dust collectors. Through the passage of air through the water layer, different-sized bubbles are formed depending on factors such as the speed of the air flow and the surface tension of the water. The sedimentation of dust in the bubbles is mainly due to the effects of inertia, gravity, and diffusion.