对脱硫塔的烟气脱硫的大型脱硫装置称为脱硫塔，而用于燃煤工业锅炉和窑炉烟气脱硫的小型脱硫除尘装置多称为脱硫除尘器。在脱硫塔和脱硫除尘器中，应含SO2的烟气，对烟气中的SO2进行化学吸收。为了强化吸收过程，提高脱硫效率，降低设备的投资和运行费用，脱硫塔和脱硫除尘器应满足以下的基本要求 ：
The large-scale desulfurization device for flue gas desulfurization of desulfurization tower is called desulfurization tower, while the small-scale desulfurization and dust removal device for desulfurization of flue gas of coal-fired industrial boilers and kilns is often called desulfurization dust collector. In desulphurization tower and desulphurizing dust collector, SO2 flue gas should be contained and chemical absorption of SO2 in flue gas should be carried out. In order to strengthen the absorption process, improve the desulfurization efficiency and reduce the investment and operation cost of the equipment, the desulfurization tower and the desulfurization dust collector should meet the following basic requirements:
（1）气液间有较大的接触面积和一定的接触时间；
(1) there is a larger contact area between gas and liquid and a certain contact time.
（2）气液间扰动强烈，吸收阻力小，对SO2的吸收效率高；
(2) disturbance between gas and liquid is strong, absorption resistance is small, and absorption efficiency of SO2 is high.
（3）操作稳定，要有合适的操作弹性；
(3) stable operation and proper operation flexibility.
（4）气流通过时的压降要小；
(4) the pressure drop of air passage is small.
（5）结构简单，制造及维修方便，造价低廉，使用寿命长；
(5) simple structure, easy manufacture and maintenance, low cost and long service life.
（6）不结垢，不堵塞，耐磨损，耐腐蚀；
(6) no scaling, no clogging, wear resistance and corrosion resistance;
（7）能耗低，不产生二次污染。
(7) low energy consumption and no two pollution.
SO2吸收净化过程，处理的是低浓度SO2烟气，烟气量相当可观，要求瞬间内连续不断地高效净化烟气。因而，SO2参加的化学反应应为极快反应，它们的膜内转化系数值较大，反应在膜内发生，因此选用气相为连续相、湍流程度高、相界面较大的吸收塔作为脱硫塔和脱硫除尘器比较合适。通常，喷淋塔、填料塔、喷雾塔、板式塔、文丘里吸收塔等能满足这些要求。其中，喷淋塔是使用最为广泛的脱硫塔类型之一，喷淋塔具有结构简单，工艺成熟可靠的优点，广泛应用于大型电厂，中小型低硫烟气治理；对于高硫烟气治理，有色行业以气动乳化脱硫塔、多层喷淋塔等为主。
SO2 absorption and purification process, the treatment of low concentration of SO2 flue gas, the amount of flue gas is considerable, requires continuous and efficient purification of flue gas in an instant. Therefore, the chemical reaction of SO2 should be very fast. The conversion coefficient of SO2 in the membrane is large, and the reaction takes place in the membrane. Therefore, it is more appropriate to select the absorption tower with continuous gas phase, high turbulence and large phase interface as the desulfurization tower and the desulfurization dust collector. Usually, spray tower, packing tower, spray tower, plate tower and Venturi absorber can meet these requirements. Among them, spray tower is one of the most widely used desulfurization tower types, spray tower has the advantages of simple structure, mature and reliable technology, widely used in large-scale power plants, small and medium-sized low sulfur flue gas treatment; for high sulfur flue gas treatment, non-ferrous industry to pneumatic emulsification desulfurization tower, multi-layer spray tower and so on.