FIELD OF INVENTION
The invention relates to a species injection lance adapted for species injection in
a nozzle. More specifically, the invention relates to an improved species injection
lance for pulverized coal injection through tuyers into blast furnace.
BACKGROUND OF THE INVENTION
A species injection lance of the art generally constitutes a circular pipe consisting
of a main pipe having a nozzle, and a small circular pipe (lance), which is
transversely inserted in the main pipe. Lance pipe is used for injection of species
into the main pipe. A distance is maintained between the tip of the lance pipe
towards its discharge end, from the intersection of the centerline of the lance
pipe and the main pipe. The lance pipe can be inserted or retracted in the
direction of its axis. Hence, the distance is variable.
For a given nozzle, the angle of the lance tip plane with respect to the center line
of the nozzle and the pipe, is normally decided ad-hoc basis to suit the
immediate and physical working advantages. Further, the position of the lance
tip along the lance axis with respect to the centerline of the nozzle is normally
fixed on the basis of the available length of the lance. In other words, the lance
tip angle and its distance from the intersections of centerlines, in the prior art,
are decided arbitrarily. Such configuration of the lance results in inefficient
dispersion of species and further causes fast erosion of nozzle body owing to the
impact of species.

OBJECTS OF THE INVENTION
It is therefore an object of the invention to propose an improved injection lance
which eliminates the disadvantages of the prior art.
Another object of the invention is to propose an improved species injection
lance, which achieves higher dispersion of species across the nozzle cross
section.
A still another object of the invention is to propose an improved species injection
lance, which causes minimum erosion of nozzle body.
A further object of the invention is to propose an improved species injection
lance, which enables efficient mixing of injected species and fluid for achieving
higher interactions of the species with the fluid.
SUMMARY OF THE INVENTION
Accordingly there is provided An improved species injection lance for pulverized
coal injection through tuyeres into a blast furnace comprising a main pipe having
a predetermined inner diameter (Dp), the main pipe having sideway provisions to
insert a lance pipe having a lance tip on insertion an imaginary plane normal to
the plane of the lance tip makes an angle 'Φ' with respect to a centerline of the
lance pipe and makes an angle 'θ' with respect to a centerline of the main pipe
and a nozzle rigidly fixed at a distal end of the main pipe the lance pipe when
inserted into the main pipe so that the said lance tip of the lance pipe is fixed at

a distance 'd' from an intersection point of the centerline of the main pipe, in
that the centerline of the lance pipe makes an angle 'α' with the centerline of the
main pipe and in that the device features achieve a relationship of Φ = (θ-α).
For a typical configuration of the pipe and the nozzle, the insertion angle of the
injection lance and the position of the tip of the lance, there exists an optimum
angle of the lance exit plane 'θ' with respect to the center line of the main pipe
and the nozzle, which gives the best possible dispersion of species and which
causes minimum contact of species with the inner surface of main pipe and the
nozzle. With this finding the development of the invention proceeds.
For a typical inlet diameter of the main pipe, an exit diameter of the nozzle, an
insertion angle 'α' of the injection lance and a distance 'd' of the tip of the lance
with respect to the centerline of the main pipe, there exists an optimum position
'd' of the lance tip along the lance axis with respect to the centerline of the main
pipe, which gives the best possible dispersion of species and which causes
minimum contact of species with the inner surface of main pipe and the nozzle.
The invention considers such a finding for crystallizing the invention.
As the spread of the pulverized species is almost the same for all angles of the
lance exit plane, so it would be better to adopt an angle which gives the least
contact angle at the inner surface of the nozzle.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Fig. 1a - Schematically shows a cross-section of the species injection lance
according to the invention.
Fig. 1b - Schematically shows a sectional view of the lance pipe according to the
invention.
Fig. 2 - shows a schematic diagram of the species injection lance indicating the
exit plane angle of the tip of the lance pipe.
Fig. 3 - Cross-section of the nozzle at the discharge end schematically showing
a) the dispersion of injected species and b) the contact angle 'β' of species with
the inner surface of the nozzle.
Fig. 4 - shows a graphical representation of variation of contact angle of species
at the nozzle tip as a function of the exit plane angle of the lance.
Fig. 5 - shows a schematic graph on the coverage of the injected species
touching nozzles periphery as a functional of the lance exit plane angle.
Fig. 6 - Schematically shows a variation in contact angle at the discharge end of
the nozzle with the variation of the lance exit plane angle (with lance tip fixed at
'd' mm away from the center line).

Fig. 7 - Schematically shows a variation in contact angle at the nozzle tip as a
function of the lance tip position from the centerline, (θ - α).
Fig. 8 - shows a variation of mass fraction of the species across the diameter at
the nozzle exit plane with different angles of lance exist plane (lance tip
positioned at the center line of main pipe).
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE
INVENTION
Figure 1(a) shows a cross-section of a circular pipe consisting of a main pipe (1)
of inner diameter 'Dp' at the inlet and a nozzle (3). A small circular pipe (2)
(lance) of inner diameter 'dp' is inserted in the main pipe (1) such that a center
line (6) of the lance pipe (2) makes an angle 'α' from the centre line (4) of the
main pipe (1). The tip (2a) of the lance pipe (2) toward the discharge end is at a
distance 'd' away from the intersection (5) of the centerline (4,6) of the lance
pipe (2) and the main pipe (1). The lance pipe (2) can be inserted or retracted
in the direction of its axis and the distance 'd' is, therefore, a variable.
Figure - 1(b) shows the exaggerated view of the cross-section of the lance pipe
(2). The tip (2) of the lance pipe (2) towards the discharge end is cut in such a
way that the normal to the cut plane (7) makes an angle 'ϕ' (also referred to as
exit plane angle) from the centerline (6) of the lance pipe (2).

Figure- 1(b) shows the exaggerated view of the cross section of the lance pipe
(2). The tip 2(a) of the lance pipe (2) towards the discharge end is cut in such a
way that the normal to the cut plane (7) makes an angle y (also referred to as
exit plane angle with the centerline (6) of the lance pipe (2).
In Figure-2, it is shown that the imaginary plane normal to the tip (2a) of the
lance pipe (2) makes an angle 'θ' with respect to the centerline (4) of the main
pipe (1) and the centerline (6) of the lance pipe (2) is at an angle 'α' from the
centerline axis of the main pipe (1). It may be noted, by difference, that the
imaginary plane normal to the tip (2a) of the lance pipe (2), that is angle 'θ' with
respect to the centerline (4) of the main pipe (1) should be equal to (ϕ+ α ) . In
other words, the tip (2a) of the lance pipe (2) is cut at an angle y such that ϕ =
(θ -α).
A stream of fluid moves at a high velocity in the main pipe 1. The species is
injected from the lance pipe (2) into the main pipe (1) and the species get mixed
and dispersed in the stream of fluid. Figure - 3 schematically shows the
dispersion of species and the contact angle 'β' of the species with an inner
surface of the nozzle (3).

WE CLAIM
1. An improved species injection lance for pulverized coal injection through
tuyeres into a blast furnace comprising:
a main pipe (1) having a predetermined inner diameter (Dp), the main
pipe (1) having sideway provisions to insert a lance pipe (2) having a
lance tip (2a), on insertion an imaginary plane (7) normal to the plane of
the lance tip (2a) makes an angle 'Φ' with respect to a centerline (6) of
the lance pipe (2); and makes an angle 'θ' with respect to a centerline (4)
of the main pipe (1); and
a nozzle (3) rigidly fixed at a distal end of the main pipe (1);
characterized in that
the lance pipe (2) when inserted into the main pipe (1) so that the said
lance tip (2a) of the lance pipe (2) is fixed at a distance 'd' from an
intersection point (5) of the centerline (4) of the main pipe (1), in that the
centerline (6) of the lance pipe (2) makes an angle 'α' with the centerline
(4) of the main pipe (1), and in that the device features achieve a
relationship of Φ = (θ-α).

2. An improved species injection lance for pulverized coal injection through
tuyeres into a blast furnace as substantially described herein with
reference to the accompanying drawings.

ABSTRACT

TITLE : "SPECIES INJECTION LANCE"
The relates to an improved species injection lance for pulverized coal injection
through tuyeres into a blast furnace comprising a main pipe (1) having a
predetermined inner diameter (Dp), the main pipe (1) having sideway provisions
to insert a lance pipe (2) having a lance tip (2a), on insertion an imaginary plane
(7) normal to the plane of the lance tip (2a) makes an angle 'Φ' with respect to a
centerline (6) of the lance pipe (2); and makes an angle 'θ' with respect to a
centerline (4) of the main pipe (1); and a nozzle (3) rigidly fixed at a distal end
of the main pipe (1); the lance pipe (2) when inserted into the main pipe (1) so
that the said lance tip (2a) of the lance pipe (2) is fixed at a distance 'd' from an
intersection point (5) of the centerline (4) of the main pipe (1), in that the
centerline (6) of the lance pipe (2) makes an angle 'α' with the centerline (4) of
the main pipe (1), and in that the device features achieve a relationship of Φ =
(θ-α).