Method for continuously removing fine dust particles from gases

A method for continuously removing fine dust from gases which contain them, consisting of: introducing the gas at a gas linear velocity of 10 to 80 m/sec and a liquid at a rate such that the liquid-to-gas ratio; L/G, is 1 to 50 l/m.sup.3, in parallel, into slit(s) or hole(s) which are set in tray(s) causing impingement onto a baffle plate which is set beneath the tray; and then carrying away the fine dust particles from the gas by the liquid, which is separated from the gas, is disclosed, along with apparatus to effectuate the process.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to a method, and an apparatus for carrying out said 
method by continuously removing fine dust particles from gases. 
2. Description of the Prior Art 
Dust collectors have heretofore been employed equipped with a venturi 
scrubber, a jet scrubber or a glass wool to remove fine dust particles 
having sizes smaller than several tens of microns. 
Gases obtained by the catalytic oxidation reaction in vapor phase, such as 
isobutylene, methacrolein, and the like contain fine dust particles of 
polymers of methacrylic acid and so on. 
Such gases usually have a dust concentration of about 100 mg/m.sup.3. A 
test for removing fine dust particles using a venturi scrubber and a jet 
scrubber revealed a maximum removal rate of 65%. When the test was 
continued for several days, the throat portions and conduits for 
exhausting the gases were adhered and clogged with solid matter, making it 
impossible to continue the operation. 
A dust collector employing the glass wool was also tested using the same 
gas as used in the above test. The rate for removing dust particles was 
greater than 98%. However, the glass wool was loaded with the solid matter 
within short periods of time, making it difficult to continue the 
operation. 
SUMMARY OF THE INVENTION 
The object of this invention therefore is to provide a method which is free 
of the above-mentioned defects. 
This invention involves apparatus for continuously removing fine dust 
particles from gases, comprising a single stage or a plurality stages of 
trays 5 having slit(s) or hole(s) 6, baffle plates 7 installed beneath the 
trays 5, and inlet ports for introducing a gas 1 containing fine dust 
particles and a washing water 2 in parallel onto said trays, wherein said 
gas and liquid are injected from said slit(s) or hole(s) and are caused to 
impinge upon the baffle plate.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The invention is mentioned below with reference to FIG. 1. Gases containing 
fine dust particles formed by the reaction in the gaseous phase and the 
washing water are supplied onto the tray of a first stage through inlet 
ports 1, 2. The gases and the liquid pass through a slit or a hole 6 at 
high speeds and hit the baffle plates 7 where fine dust particles are 
coagulated and are carried away by the liquid. The baffle plates 7 may be 
substituted by the lower trays as shown in FIG. 6. In putting the 
invention into practice, the tray, preferably, have a slit or a hole of 
such a size that the liquid-to-gas ratio L/G ranges from 1 to 50 
l/m.sup.3, and the gas linear velocity lies within a range of 10 to 80 
m/sec. 
The particles which are not removed by the tray of the first stage are 
removed in the second stage and in the third stage. The gases and liquid 
are exhausted through exhaust ports 3, 4. The trays may be installed in a 
single stage or in a plurality of stages depending upon the required rate 
for removing fine dust particles. 
Using the apparatus equipped with three stages of trays, the dust was 
removed from the gas containing polymers of methacrylic acid. The rate of 
removal was greater than 95%. The operation was allowed to be continued 
for six months without causing clogging to the apparatus or the conduit. 
FIGS. 2 to 5 show the arrangement of holes or slits formed in the tray. The 
number of the holes or slits will be suitably determined. FIG. 7 
illustrates another embodiment of the apparatus of the invention employing 
a single stage of tray. 
The apparatus of this invention is simple in construction as compared with 
the conventional apparatus, yet featuring very high rate of removing fine 
dust particles and enabling the treatment to be continuously performed. 
EXAMPLE 1 
A gas having a dust concentration of 100 mg/m.sup.3, a temperature of 
40.degree. C. and a pressure of 0.8 kg/cm.sup.2 G was supplied at a rate 
of 5.5 m.sup.3 /hr, and the washing water was supplied at a rate of 38 
l/hr into an apparatus having three stages of trays of a diameter of 60.5 
mm each having a hole of a diameter of 8.3 mm, with the distance between 
the stages being 50 mm, and the distance between the baffle plate and the 
tray being 25 mm. The pressure loss between the inlet port and outlet port 
for the gas was 1200 mmH.sub.2 O, the particle concentration in the outlet 
gas was smaller than 5 mg/m.sup.3, and the rate for removing fine dust 
particles from the inlet gas was greater than 95%. The operation was 
continued for six months. There was no clogging in the apparatus or in the 
conduits.