40
F. Dong et al.
Introduction
Smelting flue gas contains a lot of dust, which is mixed with many harmful impurities,
such as heavy metals, arsenic, fluorine, chlorine, and carbon monoxide. The particle
size distribution of dust is mostly between 1 and 100 µm. Those larger than 10 µm
can settle naturally under the action of gravity. Particles with a diameter of fewer
than 10 µm, such as PM2.5, can float in the air for a long time, and they will move
unevenly and irregularly [1, 2].
The emission of fine particles is a cause for concern because they can penetrate
deep into the lungs, thereby exacerbating conditions such as bronchitis and asthma,
which can lead to the premature death of already vulnerable people. Industrial dust
will not only cause environmental pollution, but also threaten the health of workers,
and even bring safety hazards such as explosions [3, 4].
Most of the general wet dust scrubber only uses the kinetic energy of the gas or
liquid phase, so the dust removal efficiency is not ideal. The dust removal efficiency
of particles below 5 µm, especially PM2.5, is low, which seriously affects the gas
purification and dust removal performance of the scrubber [5]. The dynamic wave
scrubber utilizes the reverse collision of gas and liquid in the pipeline to form a highspeed turbulent foam zone, thereby making full use of the gas–liquid two-phase
energy. It has the advantages of high-efficiency removal of particles and medium
pressure drop [6].
Dynamic wave scrubbing technology was first developed and patented by DuPont
in the 1970s. In 1987, Monsanto Environmental Chemical Company and DuPont
signed a license agreement, which will be used in the flue gas purification of sulfuric
acid plants and a wider range of air pollution control [7]. There have been many
related studies on the hydrodynamics of the dynamic wave scrubber. Zhou and Wang
[8] studied the dynamic wave scrubber and its hydrodynamic characteristics. They
found that the ideal performance can be achieved in the foam area. The load performance graph was drawn, and the quasi-number correlation was obtained, which was
used to predict the pressure drop of the dynamic wave device. Li et al. [9] combined
experimental research and numerical simulation methods to study the two-phase flow
field of the dynamic wave scrubber. The results show that the turbulence intensity
in the foam zone formed by gas–liquid collision is high. Chen et al. [10] studied the
hydrodynamic characteristics and gas–liquid two-phase mass transfer performance
of a reverse jet scrubber with a new three-liquid-inlet nozzle through model experiments and compared it with the currently recognized dynamic wave nozzle [11]
with good performance. The results show that the new three-liquid-inlet nozzle has
a good mass transfer effect and better operational flexibility. Wang et al. [12] studied
the influence of liquid–gas flow rate ratio, liquid jet velocity, and gas velocity on the
pressure drop and dust removal efficiency of the dynamic wave scrubber. Compared
with the venturi scrubber, the pressure drop and the fog entrainment concentration of
the dynamic wave scrubber are lower, so it is more practical. There are some other
studies on the dust removal efficiency of scrubbers, but most of them use common
F. Dong et al.
Introduction
Smelting flue gas contains a lot of dust, which is mixed with many harmful impurities,
such as heavy metals, arsenic, fluorine, chlorine, and carbon monoxide. The particle
size distribution of dust is mostly between 1 and 100 µm. Those larger than 10 µm
can settle naturally under the action of gravity. Particles with a diameter of fewer
than 10 µm, such as PM2.5, can float in the air for a long time, and they will move
unevenly and irregularly [1, 2].
The emission of fine particles is a cause for concern because they can penetrate
deep into the lungs, thereby exacerbating conditions such as bronchitis and asthma,
which can lead to the premature death of already vulnerable people. Industrial dust
will not only cause environmental pollution, but also threaten the health of workers,
and even bring safety hazards such as explosions [3, 4].
Most of the general wet dust scrubber only uses the kinetic energy of the gas or
liquid phase, so the dust removal efficiency is not ideal. The dust removal efficiency
of particles below 5 µm, especially PM2.5, is low, which seriously affects the gas
purification and dust removal performance of the scrubber [5]. The dynamic wave
scrubber utilizes the reverse collision of gas and liquid in the pipeline to form a highspeed turbulent foam zone, thereby making full use of the gas–liquid two-phase
energy. It has the advantages of high-efficiency removal of particles and medium
pressure drop [6].
Dynamic wave scrubbing technology was first developed and patented by DuPont
in the 1970s. In 1987, Monsanto Environmental Chemical Company and DuPont
signed a license agreement, which will be used in the flue gas purification of sulfuric
acid plants and a wider range of air pollution control [7]. There have been many
related studies on the hydrodynamics of the dynamic wave scrubber. Zhou and Wang
[8] studied the dynamic wave scrubber and its hydrodynamic characteristics. They
found that the ideal performance can be achieved in the foam area. The load performance graph was drawn, and the quasi-number correlation was obtained, which was
used to predict the pressure drop of the dynamic wave device. Li et al. [9] combined
experimental research and numerical simulation methods to study the two-phase flow
field of the dynamic wave scrubber. The results show that the turbulence intensity
in the foam zone formed by gas–liquid collision is high. Chen et al. [10] studied the
hydrodynamic characteristics and gas–liquid two-phase mass transfer performance
of a reverse jet scrubber with a new three-liquid-inlet nozzle through model experiments and compared it with the currently recognized dynamic wave nozzle [11]
with good performance. The results show that the new three-liquid-inlet nozzle has
a good mass transfer effect and better operational flexibility. Wang et al. [12] studied
the influence of liquid–gas flow rate ratio, liquid jet velocity, and gas velocity on the
pressure drop and dust removal efficiency of the dynamic wave scrubber. Compared
with the venturi scrubber, the pressure drop and the fog entrainment concentration of
the dynamic wave scrubber are lower, so it is more practical. There are some other
studies on the dust removal efficiency of scrubbers, but most of them use common