Note: Descriptions are shown in the official language in which they were submitted.
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Report describ;llg patent for invention - "IMPROVED PROCESS
FOR THE~ GRANUL~TING OF SULPHU~ AND A SULPHUR
GRANULATOR", which consists of solidi-lying sulphur in granules by
me~ms of specially designed equipment, - where two jets of water come
into touch with liquid sulphur upon a rotating disk.
Not only in the plants where sulphur is produced by synthetic
processes but also in those where it is remelted to he purif;ed, one of the
major difficulties met with still is how to pack it. The method followed
has been to lead the melted sulphur into a cooling vessel or pool (usually
a long and shallow one, for obvious reasons) where it soliclifies in a
compact block. Such block is then mechanically broken up, for which the
simplest of hand tools up to percussion vibrators, break the sulphur ;nto
lumps that are packed and sent off to consumers.
Ihere are several drawbacks to this method: there must be a
relatively large area for the pools; it is very difficult to break up the
sulphur and lumps are not always of an even size; a great deal of labour is
required (people to look later emptying in the melted sulphur and others
to break it up in its solid state even though working with serni automatic
tools only); and the risk of accidents when doing the breaking up.
l o overcome such shortcornings the applicant had developed a
process and a granulator, which were described in Brazilian Patent No. PI
8001894, whereby the sulphur hardened rapidly at the unloading point and
its granulation was even and could be governed. The granulator consisted
of an assembly of a nozzle, a disk, and a bowl.
In Brazilian Patent No. PI 8001894 the nozzle had a hollow
cylindrical jet of melted sulphur and within it there was a conical jet of
water. Both Jets hit a disk on a shaft about which the disk could turn
when struck by the water and the sulphur. The tilt of the disk could be
graduated. The water and the sulphur hitting the disk off center made it
spin, whereupon sulphur hardened into granules and was thrown off the
disk by centrifugal force and went into a suitable bay.
However in the first assemblies so built, the water did not strike the
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su1phur well enough and this le~l to sulphur stalagmites appearing in the
bay. Also the clesign of the nozzle from which the sulphur issued enabled
a "cushion" of sulphur to grow upon the disk and the latter becoming
heavier went past its optimum tilt. Such sulphur "cushions" also caused
bigger lumps of sulphur to be created, standing out among the even size
and finer particles in the rest of the pile. The "cushion" so created meant
that the granulating chamber had to be brought to a stop.
A granulator has now been developed with a better nozzle whereby
the process of squirting the water and the sulphur has been changed, the
granulating process having thus been improved.
In this improved process part of the water is turned aside into an
extra jet in the middle of the hollow cylindrical jet of melted sulphur. It
hits the disk which is on a shaft able to turn freely whenever struch,
between the center and the periphery of such disk, features of the process
being that:
a) a jet of water is provided inside the cylinder made up by the
aforesaid jet of sulphur;
b) a further jet of water is provided around the jet of sulphur;
c) the jets of water and sulphur hit the aforesaid disk;
d) sulphur hardens broken up into granules as a result of the
two jets of water striking sulphur;
e) said granules and the water are spun ou$ beyond the surface
of the disk which leaves the latter largely free from any hardened sulphur.
The granulator of this invention has a new nozzle with holes
pointing downwards all round its circumference. It is provided with the
means of letting jets of water out from below, one jet inwards of the
cylinder that passes through the aforesaid circumference and the other jet
outwards of such cylinder. There is also a disk on a shaft which can turn
freely about such shaft, said disk lying below the holes in the nozzle. The
liquid sulphur issu;ng from the holes does so as a jet which hits the disk
between its center and its periphery. There is also a means of graduating
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the tilt of the disk.
In the drawings appended ~o this specification:
Figure 1 is ~ vertical section view of the no~zle of the granulator
invented;
S Figure 2 is a section (AA' of figure 1) of the base of the nozzle, showing holes in such base; and
Figure 3 is a section of the disk as it would be tilted in relation to
the nozzle in figure 1.
A description of the invention follows, referred to figures 1, 2, and
3, which description is not a limiting one.
Pipe, 1, which is part of the means for conveying the melted sulphur
connects the granulating equipment to a store of melted sulphur. Pipe 1
leads into chamber 6. Pipe 1 is surrounded by pipe 2 and the chamber is
surrounded by liner 4 which is a continuation of pipe 2. Pipe 2 carries
steam intended to keep the sulphur in a melted state until after it is
ejected. Obviously liner 4 serves the same purpose. Steam comes in from
inlet 3. The drain for the water condensed from the steam is not shown.
The bottom of chamber 6, which is round3 has a lot of holes, 5,
arranged around the circumference concentrically with the outside edge of
the round bottom of such chamber 6.
The number of holes may be different, but sixteen is usual. It
should be noted that the holes must go through not only the bottom of
chamber 6 but also the thickness of liner 4, before the sulphur can issue
forth.
~or the invention the applicant used a metal ring, 17, which goes
around the bottom of the chamber, its average radius being the same as
that for the circumference described by the set of holes, such holes being
drilled into the aforesaid ring. Small horizontal holes, 18, are arranged
radially around the ring, so as to enable space at 19 to be provided with
steam. Such small holes are at right-angles to holes 5, there being one for
them between every two o-f holes 5. This arrangement turned out to be
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quite sturdy, however any other wllich lets the sulphur run through will do.
Chamber 6 ;s cylindr;cal in shape and to its side a ring-shaped p;pe,
8, is fixed, which may be provided with a support, 7. The cold water that
comes in from inlet 9, circulates in such pipe 8.
S CoImected to pipe, ~, in front of inlet tube, 9, there is an opening,
10, which feeds water to the inside jet creating means described next.
Such opening, 10, lies at the end of horizontal pipe, 11, which continues
within vertical pipe, 12, up to outlet, 13, leading downwards, which lies in
the middle of the bottom of the chamber. Pipes 11 and 12 run within a
pipe which is slightly wider in diameter, which means that there is a space
around them. Such space lies between two walls, one hot and the other
cold, since around such space 14 there is melted sulphur flowing and inside
it (within 11 and 12) there is water flowing.
Let us now describe how the water jet gets out. Pipe 8, already
mentioned, has a slit, 15, which runs all the way round the under side of
the ring. ~he water jet comes through slit 15, concentrically with the
sulphur jet, and encircling it.
Two small concentric walls, 16, are welded to the edges of such slit,
all around such edges, thus enabling the water to flow more easily and
creating a suitable outside jet.
The rat;o of the quantity of outside to inside jet water is usually
0.25 to 1.5.
Flanges or any other kind of usually employed device will serve to
join the granulator to a source of supply.
Once pipes 1 and 9 have been fed with sulphur and water this
invention can be put into practice.
In figure 3 the three jets are striking disk 20 which is on a shaft, 21,
they strike the disk somewhere between its middle and its outside edge.
A diffuser may be placed ahead of outlet 13 so as to impart a
conical shape to the inside jet of water.
Anyway, the three jets will make the disk turn according to the
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- 6 -
Anyway, the three jets will make the dislc tLlrn according to the
quant;ty of force imparted thereto. Jets will make disk, 20~ turn faster or
slower accorcling to how it is ~ilted, and such tilt may be to either side. In
the figure the angle alpha, that between the disk and the horizontal, ma~
S be either upwards or downwards. Tilt of the disk is governed by suitable
means, it being the shaft that it tilted and this ~hich can be done by
sliding screws, for instance. Rate of turn is ~lso a function of speed at
which sulphur and water flow.
When the disk is turning and the jets are striking it the water will
cause the sulphur to harden evenly in small granules which will issue by
centrifugal force and gather in a container not shown in the figure.
With two jets of water wetting is thorough, and also less sulphur
fumes are given off, while no "cushions" at all appear on the disk nor
stalagmites in the pools. Also the inside jet does not have to be conical
lS and even so water-sulphur contact is excellent.
An important parameter used to checll~ on the quality of the sulphur
secured under this process is particle size. It is a very important point in
the process, for if the sulphur hardens in big lumps it will become difficult
to get it out, while on the other hand, if the droplets of sulphur are too
small there will be a great deal of fines which will be dragged away by the
water and large si~e separators will be needed to reco~er such sulphur out
of the cooling water. The optimum particle size is arri~ed at by matching
the diameter of holes, 5, that let the sulphur into the nozzle, to the
pressure and rate of flow of the cooling water.
Table I shows typical particle size of output from an industrial
plant:
Table (I)
% Aggregate
Screen Retained ~o retained
_
1/4"............. 7.87..... 7.87
S mesh Tyler..... 12.79.... 20.66
1 ~ 1 Ll 6 7 1
- 7 -
16 mesh Tyler.... 30.53.. 83.59
24 mesh Tyl~r.... 5.32... 88.91
28 mesh Tyler.... 1.59... 90.50
42 mesh Tyler.... 3.91... g4.41
60 mesh Tyler.... 1.87... 96.28
80 mesh Tyler.. e... 1.07... 97.35 i
80 mesh Tyler.... 2.65... 100.00
A second important parameter concerning the quality of the sulphur
is its moisture content. At first glance it would seem that since so much
10water is used in the process the sulphur output would be very wet, but this
is not so.
The water drains rapidly away from the pile so that the moisture
content of the sulphur becomes reasonable after a few hours, as is to be
seen from Table II.
15TABLE (II)
Sulphur moisture content
Hours % bv wei~ht
.................................. 6.5 -------------------
16 ...................................... 6.0 ----------
.................................. 5.0 --------
38 .................................. ~.7 ----------
63 .................................. 4.2 ----------
