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CA 02933108 2016-06-08
POWER GENERATING METHOD OF CARBON-MOLECULE GASIFICATION
COMBUSTION BOILER
Cross-reference of the invention application
The invention application claims priority of two Chinese invention
applications: an application
whose application NO is 201310653009.8 and title is a method of carbon
molecular gasificaton
combustion in coal based boiler of electricity plant and an application whose
application NO is
201410400491.9 and title is a power generating method of carbon molecular
gasification
combustion boiler (furnace).
Technical field
The present invention relates to a clean coal combustion power generating
method, in
particular a power generating method of a gasification combustion boiler
designed in the level
of molecule of the coal.
Background art
Nowadays, the climate change, environmental deterioration and resources
shortening have
been a world wild problem. The saving energy and reduction of discharge and
adaptation to the
climate change have already become a hot topic and focus of world politics
from technology.
The current status of China is a county of energy production and consumption
mainly
depending on coal due to more coal, less gasoline and shortage of natural gas.
The
consumption of coal already is half of total amount of world consumption of
coal and in more
than 80% thereof, the traditional direct combustion type (grate laminar flow,
fluid bed
combustion, powdered coal combustion, briquette and coal water slurry) is
still utilized. The
environment scientist believes that the direct combustion type is also a main
pollution source
causing dust-haze in current China.
However the direct coal combustion type will still be utilized worldwide, such
as the power
generating method of the coal combustion with high efficiency and low
discharge in
2021-2050 indicated by International Energy Bureau will still adopt the direct
combustion
technology of the recycling fluidization bed boiler and powered coal boiler.
China also sees the
recycling fluidization bed boiler and powered coal boiler as an important
technology in the
CA 02933108 2016-06-08
future. These come from unrealiz,ation in the basic theory: the direct
combustion technology in
which the solid-phase mass in the coal is combined with the thermo
decomposition gas-phase
mass and therefore burned in the same one hearth betrays the nature and law of
gas-phase mass
or solid-phase mass respective. The completeness of the direct combustion
requires excess air
( a 1.2), which results in a great number of poisonous and hazardous
pollutants (S0x, NOx
and so on) related to oxygen produced during the combustion and then
controlling them again.
In so doing, not only the process is complicated, but also the cost is high
and even a following
status is caused: "controlling pollution and producing pollution", discharge
is unstable and the
controlling pollution is unable to reach the standard.
At present, the worldwide developing coal-based IGCC technology is of high
power-generating
efficiency but of a less benefits. Meanwhile its promotion and realization is
limited a great deal.
The essential reason thereof lies in utilization of the traditional coal
gasification technology
with high specific surface, high temperature and high pressure.
As to the above mentioned technology, worldwide conventional efficiency and
common
standard is balanced in the following way: maximizing Q energy of used coal/ (
Q original total amount of
energy of coal ) and minimizing ( B discharging amount of pollutants using
coal ) /13 total amount of original pollutants
of coal.
Summary of the invention
In view of the above mentioned status, the present invention proposes an idea
of energy and
environment protection efficiency during utilizing coal in a following way:
Controlling the following ratio the same time so that the former is maximized
and the latter is
minimized:
Q energy of used coal/(Q original total energy of coal Q total consumed energy
as utilizing coal)
(B pollutants discharging amount as utilizing coal+ B controlled pollutants
discharging total amount)/B total amount of original
pollutants of coal.
Therefore, a thorough quantization check and development. A power generating
method of
coal gasification combustion boiler designed from the level of molecule from
process
innovation. The advantages of the process lie in the pollutions are controlled
in the origin, the
elements are reduced in quantity and the environment protection and saving
energy are
achieved with high efficiency.
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The technical route for this objective is that first the raw coal added with
desulfurization agents
is carried to the molecular gasifier so as to be desulfurized and gasified
into a clean heated (hot)
coal gas and then is sprayed into a boiler to be burned; the high temperature
smoke and gas will
pass the heated surface of the boiler to exchange heat and then go out of the
chimney; the
steam (hot water) produced in the boiler will drive the gas turbine to power
generation (heat
supply).
The molecular gasifier adopts a mechanism of a complete oxidization of a thin
bed with a large
interface matching a positive reduction of a thick bed with a small cross
section to produce gas;
the molecular gasifier is provided on the upper reduction zone thereof with an
annular point
measuring temperature and is correspondingly provided on the lower oxidation
zone thereof
with an annular hole for spraying steam; during operation, an adjustment can
be made with
steam depending on the change of temperature on the measurement point so as to
meet timely
and equally process requirements to ensure the gasification reaction to stably
proceed; the
molecular gasifier can desulfurize the coal by desulfurization agent in the
absence of oxygen so
that the ration in component of Ca and S approaches 1; the heated coal gas in
the hearth of the
boiler is burned by adoption of low excess air ratio a approaching 1 so that
10 percent or more
air can be saved and the poisonous and hazardous mass related to oxygen can be
reduced; the
boiler is on the lower part with a housing to remove coke (dust) which plays a
role of refining
coke or removing dust; during operation, depending on the quality and need,
the refining coke
can be selected and at any time the function of combustion dust removal can be
turned on.
Brief descriptions of the drawings
Fig.1 is a flow chart of a power generating method of a typical gasification
combustion boiler
of the present invention;
Fig. 2 is a view of a typical improved molecular gasifier and an adjusting
system of the present
invention;
Fig. 3 is a structural view of a typical combustor provided on two sides
symmetrically of the
boiler of the present invention;
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Fig. 4 is a structural view of a typical combustor provided on three sides of
the boiler of the
present invention;
Fig,5 is a structural view of a combustor provided on one side of the boiler
of the present
invention;
Fig.6 is a structural view of a typical combustor provided on four sides
symmetrically of a
super large boiler of the present invention;.
Best carried-out examples
Referring to the drawings 1, 2, 3 and , the present invention is more detailed
described.
The raw coal can be divided by a sieving process into a particle coal A in
which powered coal
with a diameter of less than lOmm is added with calcium so that the ratio in
component
between Ca and S approaches 1 and is produced into a coal ball B and hence the
coal ball B is
baked by the exhaust heat into a dry coal ball c with qualified moisture
content ( this
preparation system for coal can save more 50% electricity than powder produced
by coal), and
again the particle coal A and dry coal ball C are carried into molecular
gasifier 1 by a
coal-adding machine to produce gas. The gasification agents are carried
through a grate from
the bottom of the boiler (the pressure of the gasification agent for producing
combustion gas is
lower than 0.5kpa which is decreased by 58% compared to the wind pressure of
the
combustion technology of the current powdered coal and fluidization bed which
is higher than
or equal to1.2kpa,, therefore the respective saving electricity ratio is 58%).
the coke is
discharged out of the bottom of the boiler by the grate. The molecular
gasifier 1 uses an
innovative complete oxidization 1-6 of a thin bed with a large interface
matching to a positive
reduction reaction 1-5 of a thick bed with a small cross section to produce
gas, which is a
gasification process designed from the molecular level and ensures a
sequential operation of
the reaction inside the boiler and hence increases with high efficiency the
gasification (the
electricity consumption is less than 1% of that of current gasification with
high temperature,
high pressure and fluidization bed in terms of the same quality of coal, the
same production
amount). The complete oxidization of the thin bed with a large interface 1-6
distributes the raw
material into a thin bed with a large surface area by means of the structure
of the lower
= 4
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oxidization section of the molecular gasifier 1, which causes a first
interface in contact with the
gasification agents sprayed into inner grate 1-8 of the boiler and outer grate
1-7 of the boiler to
be enlarged and therefore speed up the operation speed of the oxidization
reaction of C+02=
CO2+Q and makes it more complete. The positive reduction reaction 1-5 of the
thick bed with
a small cross section is formed and realized by the upper structure of the
molecular gasifier 1,
and extends the time of contact between reaction mass in CO2+C=2C0-Q and
increases the
speed of the ascending hot liquid and hence speeds up the effect of the heat
convection and the
mass transfer by convection so that the temperature of the pillar-form raw
material under
reduction reaction is increased and meanwhile the carbon dioxide in the
reaction material can
be rapidly compensated. Due to the factors mentioned above, the speed of the
reduction
reaction is increased so that the reaction is complete and full. In order to
meet process
requirements and to balance the reaction temperature, the molecular gasifier 1
is provided on
the upper reduction zone with an annular point of temperature measurement 1-2
corresponding
to an annular steam spraying hole 1-1 provided on the oxidization zone
thereof. During
operation, when measured temperature on the measurement point goes beyond the
required
value and the annular temperature difference goes beyond a fixed value (
depending on the
quality of the coal), the controlling system automatically (manually) turns on
the lower jet duct
1-1 to use the steam to enter the adjusting course (this regional adjustment
is timely, accurate
and effective). The molecular gasifier 1 desulfurize the coal by adding
calcium to produce the
gas in the absence of oxygen and hence the following component ration can be
designed based
on the sulfure content ratio and discharging standard of the raw coal: the
ratio of Ca and S
approaches 1 so that the target of desufurization is reached with high
efficiency. The coke
containing calcium can be discharged out of the bottom of the boiler by the
grate to be reused
as a raw material of cement, The hot coal gas enters into the outer combustor
2 and passes the
housing 6 of coke removal or the combustion chamber 6 of dust removal (the
dust removal
housing 6 can have two functions of refining coke and removing dust: 1 in
accordance with the
coal quality and as desired, the air valve of the outer combustor 2 is
switched off so that the
housing 6 refines coke by the effect of impact drive force, the obtained coke
is a raw material
for production of coal-based active charcoal; 2 it can also can be switched to
other functions as
desired to activate and adjust the air to cooperate with the hot coal gas for
the combustion and
removing dust) and goes into the inner combustor 5 again to be burned
completely. The coal
gas is produced by the combustion with low excess air efficient a approaching
1 (in so doing,
10% or more air can be saved and respectively the poisonous and hazardous
material related to
CA 02933108 2016-06-08
oxygen such as S0x, NOx is decreased). The hot coal gas with high temperature
passes the
heated side of the boiler 3 to exchange the heat and goes out of the chimney.
During the
gasification combustion, a precaution of pollution is given in the origin and
the elements are
decreased and hence a high efficiency environment protection and saving energy
is realized.
The steam (hot water) produced by the boiler 3 drives the gas turbine to
generate power ( to
supply heat).
Figure 2 is view of a typical improved molecular gasifier 1 and controlling
system, the
reference numeral 1-1 designates the annular steam spraying hole; 1-2 the
annular temperature
measurement hole; 1-3 coal adding port; 1-4 exit of the coal gas; 1-5 the
reduction reaction
zone of thick bed with a small cross section; 1-6 the oxidization zone of the
thin bed with a
large interface; 1-7 outer grate; 1-8 inner grate; the coke is discharged out
of the bottom of the
boiler; the gasification agent is sprayed into through the grate. Such
molecular gasifier 1 and
gasification method not only produces clean hot coal gas and ensures to obtain
a
high-efficiency combustion boiler and various furnace, but also can be
utilized cooperatingly in
the power generating system of the gas interior combustion engine and the gas
turbine to
produce the desired cold coal gas and raw chemical gas. The amount of
gasification is high and
the strength of gasification is 1000-2600kg/m2.11 and large scale of the
process can realized
(some thousand ton of production per single boiler and each day). The
operation cost is
low( the electricity consumption is less than 1% of that of the gasification
bed and fluidization
bed with similar coal quality and similar output of production).
Figure 3 is a structural view of a typical combustor provided symmetrically on
two sides of the
boiler of the present invention, 2 designates the outer combustor which can be
switched on/off
and adjust the air to spray and blow downward the coal gas; 3 the hearth of
the boiler; 4 coke
removal hole or dust removal hole; 5 inner combustor; 6 the housing for
removing coke or
combustion chamber for removing dust; 7 the coal gas cavity of the combustor;
8 the air
chamber of the combustor; 9 the wall of the combustor which is provided with
air spraying
holes; 10 the air chamber of the inner combustor,
Figure 4 is a structural view of a typical combustor provided on three sides
of the boiler of the
present invention. 2 designates the outer combustor spraying and blowing
downwardly; 3 the
hearth of the boiler.
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Figure 5 is a structural view of a typical combustor provided on one side of
the boiler of the
present invention. 2 designates the outer combustor spraying and blowing
downwardly; 3 the
hearth of the boiler.
Figure 6 is a structural view of a typical combustor provided on three sides
of the super large
scale boiler of the present invention. 2 designates the outer combustor
spraying and blowing
downwardly; 3 the hearth of the boiler.
Due to the carbon-molecular gasification combustion technology, the precaution
from the
origin is realized and the elements are decreased. The pollution is
scientifically resolved and
the environment protection and energy saving is kept in the whole course. The
cost is low and
the long-term operation is stable and liable. The invention can also gasify
and burn various coal,
biological substance and other organics (waste). The invention can refine the
coke and remove
the dust alternatively in accordance with the need and the coal quality.
Therefore, the present invention has a wide usage almost in all the domestic
market and in
various equipment using coal, oil, gas and electricity as fuel. Furthermore,
the benefits of
environmental protection and economical benefits are large.
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