Note: Descriptions are shown in the official language in which they were submitted.
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This invention is related to United States Patent No. 4,025,282
issued May 24, 1977, enti~led APPARATUS TO BURN LIQUID FUELS IN A GASEOUS
FUEL BURNER, and to United States Patent No. 4,148,599 issued April 10, 1979,
entitled METHO~ FOR MIXING LIQUID FUELS WITH DILUENT GAS FOR A GASEOUS FUEL
BURNER.
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This invention lies in the field of liquid and gaseous fuels and
fuel burners. More particularly, it concerns the method of preparation or
modification of liquid uels so that they can be vaporized and burned in a
d normal gaseous fuel burner.
Still more particularly, it concerns the design of a fuel system
which can utilize liquid fuel and water to provide a vaporized liquid fuel-
steam fuel, which can be burned alternatively with a natural gas fuel in a
gaseous fuel burner.
Because of the restricted supplies of gaseous fuels, which are
particularly in the natural gas category, it is at times necessary to burn
liquid fuel as replacements for the normally used gaseous fuels. This is
common where fuel burning is required in the operation of industry such as
the chemical and petroleum industries, where all functions of production re-
~` sult from the application of heat in some manner or other.
2~ The prior art is illustrated by the two United States Patents;~ 4,025,282 and 4,148,599. However, while they describe certain useful pro-
casses, there is a much larger field of application of the principle of llquid
fuel vaporization, which is in the area of th vaporization of mixtures of
liquid ~uel and water, which is described in this application.
It is the primary object of this invention to provide a fuel burning
system i~ which either gaseous or gasified liquid fuels can be burned alter-
natively without any change in burning equipment.
It is a further object of this invention to provide a liquid fuel
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: burning system in which the liquid is fully Yaporized s.o that it is handled
identically to a gaseous fuel.
According to the present invention there is provided a method of
:
: preparing liquid fuel for use alternatively or with a normally gaseous fuel
burner having at least one orifice comprising the steps of:
(a~ mixing said liquid fuel with ~ater in a selected ratio;
(b~ emulsifying said mixture of liquid fuel droplets and water;
(c~ indirectly heating said emulsified mixture of liquid fuel plus
water until said liquid fuel and said water vaporize, and a mixture of
combustible fuel-vapor and steam is formed; and ~.
(d~ flowing said mixture of combustible vapor plus steam under ~:~
pressure into said gaseous fuel burner.
These and other objects and advantages of this invention and a better
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understanding of the principles and details of this in~ention will be evident
from the following description, taken in conjunction with the appended draw-
ings, in which:
Figure 1 shows one embodiment of the invention.
Figure 2 shows a simplified embodiment of the invention.
Referring now to the drawings and, in particular, to Figure 1, there
;` is indicated by the numeral 10 one embodiment of the invention. A stream of
water indicated by the arrow 16, and a stream of liquid fuel indicated by the
arrow 14, flow into a mixer 12, which may be of conventional design. The out-
let of the mixer flows into an emulsifier 18 to provide an emulsion of the
liquid fuel and water, which flows by pipe 22 into a heater unit indicated
generally by the numeral 24. This can be of conventional design. Illustrated
in Figure 1 is a fuel fired furnace 26, which is shown schematically, supplied
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with fuel 30 through a burner opening 28 and supplied combustion air 32, to
provide a high temperature environment insid~e the furnace 26, to heat the in-
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-l ternal piping 36, through which the emulsion of liquid fuel and water flows.
The hot products of combustion flow in accordance with arrow 34 up the stack
~`~ 35 in a conventional manner.
The outlet pipe 38 now contains a flow of vaporized liquid fuel and
2Q steam~ ~which goes through an appropriate valve 40, and to a gas fuel line 42
to the burner. At the junction 41 another pipe joins the line 42 and sup-
~ plies a gaseous fuel 44 through a valve 46. By~controlling valves 40 and 46
; ; either one or the other source of gaseous fuel can be provided to the burners.
B~ controlling the ratio of liquld water to liquid fuel, the partial
pressure of fuel vapor to water vapor can be changed andg thus, the temperature
and the heat content of the gaseous fuel can be made any desired value.
`~ Operationwise, the liquid vapor and steam in line 38 is operatively
similar to that of the conventional gaseous fuel 44, so that no mechanical
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changes are required in the burner to substitute one fuel for the other.
In Figure 2 is shown a modification of the system 10 of Figure l,wherein the liquid fuel 14 and water 16 are simply mixed in the mixer 12, to
form a mixture of droplets of oil and water to flow by line 50 to the heater
52.
~ n this case the heater is shown as a heat transfer device, rather
than a furnace as in Figure l. This heat transfer device can utilize waste
heat from hot byproducts of other process operations, that may be available.
This is shown schematically as a heat transfer device with hot fluid entering
at the top through line 54 and passing down in counterflow through the mixture
o~ liquid fuel and water, which is 10wing up through pipes in the interior
of the heater. The cooled hot fluid leaves through line 56.
The heated gaseous fuel now at a high enough temperature to vaporize
both the liquid fuel and the water~ leaves by line 38 to go to the burner as
in Figure 1.
l It is clear that the liquid fuel a;nd water can be mixed in various
i ~ ~ays. They can be simply mixed, or they can be emulsified to form droplets
~` of one 11quid in the other. The liquid fuel can be a~omized and then mixed,
or emulsified wlth the water, e~c. The heat~ing can be carried out in any
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~20 su~table manner so as to provide the proper temperature and pressure, and so
as to st efficiently utilize heat that is available.
~hat has ~een described is apparatus~for the use of a mixture of
liquid water and distillate oil prior to vaporization, for suppl~ of diluent
vapor for the vaporized distillate after the vaporization of both oil and
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water, for use as a substltute gaseous fuel, in burners designed for the burn~
ing of gaseous fuels only. In this case, the initially liquid water is vapor-
- ized along with the distillate fuel oil, to serve as diluent gas for vaporized
liquid distillate oll. Dilution of v~porlæed distillate oil is demanded for ~`
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` suitable gaseous fuel calorific control, since vaporized water is free of
calorific value. Selected quantities of oil and water are simultaneously
- vaporized for creation of a preferred gaseous fuel. The vaporization occurs
at a selected, and suitable pressure and vaporization temperature, which is
suited to the vaporization pressure, in order to maintain both oil and water
in vapor-phase at delivery to burners. Partial-pressures of oil vapor and
water vapor determine required temporature,as is well-known to those versed
in the art.
An exemplary condition might be the creation of 910 btu/cu ft sub-
stitute gas at 15# gauge pressure ~29.7# Absolute Pressure) using a prior mix-
ture of typical #2 oil (house~ heating oil~ and liquid water at a final
vaporization/superheat temperature of 400F (204.4C). The calorific value at
910 btu/cu ft is based on the Lower Heating Value of the fuel. The data, per
million btu for gas fuel produced per hour are as follows:
#2 oil - 7.524 gallons or 54.9# or 92.4 SCF as vapor.
Water - 5.717 gallons or 47.68# o:r 1,006 SCF as vapor.
; Total gas volume - SCF - 1,098.4 SCF/MM btu/hr at 400F (204.4C)
The data, as presented are for 910 btu/SCF L~ gas only, and they
~ill be modi~ied as required for other calorific value gas. The function of
~20 oil-water emulsification, as shown in Figure 1, can be carried out by a
typical impeller~driven centrifugal pump to excellent advantage, but a typical
` gear-pump is not considered as satisfactory.
It is noted that the configuration of Figure 2 is the preferable
form of our invention because no fuel firing is required, and the use of some
already heated process fluid as a heat-medium conserves fuel through avoiding
direct-firing for vaporization. The heat-medium fluid can be any which is
available at suitable temperature level for oil-water vaporlzation at required
pressure, which is typically the case. The configuration of Figure 1 is next
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in the order of decreasing preferability due to required fuel usage. The
simple mixer of Fig~re 2 can be applied ~o either Figures 1 or 2, since the
function of oil-water emulsification prior to vaporization is not present.
All embodiments shown make use of the identical phenomenon, which
is pre-mixture of the liquids, oil and water, prior to vaporization and super-
- heat, for use as substitute gaseous fuel. In the emulsification step the
phase of vaporiza~ion is improved. ;~
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