JPH0297591A - Method for combustion of carbonaceous substance in oven - Google Patents

Abstract

PURPOSE: To reduce the generation of soot, and keep the generation of NO_x within an allowable level, by sending ferrocene included in carrier into the fire balls in a coal fired furnace.

CONSTITUTION: The pulverized coal is supplied into a furnace together with the air, and burned to form the fire balls. In this case, the amount of the air to be sent is controlled to be less than the standard amount of the air necessary for combustion, and ferrocene (dicyclopentadienyl iron compound) of the formula (R and R' are independently H, alkyl, cycloalkyl, aryl, or heterocyclic group) is sent together with the carrier liquid, to keep the combustion efficiency and to control the generation of NO_x less than the allowable level. The addition quantity of ferrocene is 0.1-100 ppm of the coal as Fe, and the combustion efficiency of the fire balls in the latter stage is improved, the generation of the soot is reduced, and the quantity of NO_x can be kept in a permittable level, when the addition quantity of ferrocene is 0.5-100 ppm.

COPYRIGHT: (C)1990,JPO

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Application of Earth Collection The present invention relates to methods and additive compositions for improving combustion efficiency in coal combustion furnaces and other related types of equipment.

BACKGROUND OF THE INVENTION Considerable research has been conducted regarding coal-fired furnaces for heat generation. Such combustion furnaces are regarded as an environmental protection problem in most industrial areas.In the combustion of coal, various combustible organisms emitted from the stack of the system cause environmental pollution. Particularly problematic:
One is soot emissions from coal-fired furnace stacks. This is mainly due to incomplete combustion of coal in the furnace. Various means have been used to remove soot from emissions, but there is an economic balance between how much soot is removed and how much it costs. In order to reduce the burden on the soot removal system, it is useful to improve the combustion in coal-fired furnaces.From this point of view, various methods have been developed that focus on controlling the particle size of the pulverized coal fed to the fireball of the combustion furnace. means have been used. In addition, adjustments have been made to the air supply in order to achieve as complete a combustion as possible within the furnace. Attempts have even been made to add various catalysts and the like to pulverized coal to enhance combustion within the fireball.

Controlling soot has also been studied with respect to the combustion of heavy oil in oil-fired furnaces, e.g., U.S. Pat.
818,416; 2,898.359; 3,122
, 577:3.217,022.3,341,311.
No. 3,535,356 and No. 3,989°731, it is disclosed that ferrocene, an iron-containing compound, has been used to improve the combustion of heavy oil and gasoline. It is also known to use ferrocene as an additive to improve the combustion of solid propellants such as jet fuel, and such use is described in U.S. Pat. No. 2,694,721; 3. 564
,034°3.577.449; 3,739,004
; 3.813,307.3,816,380°3,8
78.233 and 4.108.696.

Problems to be Solved by the Invention] The object of the present invention is to solve the above problems and find a means for improving combustion even in the case of coal combustion.

[Means for Solving the Problems] It was surprising for the present inventors, and it became related to the present invention, that one or more of ferrocene or its derivatives was By feeding it in a carrier into the fireball of a coal-fired furnace, the combustion in the fireball is clearly improved, the soot emissions are clearly reduced, and the N08
emissions were found to be maintained at acceptable levels.

Yet another aspect of the invention provides a process for improving combustion efficiency while maintaining acceptable levels of combustion-produced N01 in a coal-fired furnace. The coal-fired furnace includes at least one location for introducing pulverized coal into the furnace to form and maintain a fireball within the furnace, and combustion of the pulverized coal within the fireball. It has at least one place for introducing air for support.

This process uses an effective amount of air to significantly improve combustion efficiency while maintaining N08 emissions at acceptable levels by controlling the amount of excess air required to support the combustion of pulverized coal. It consists in introducing an additive at least in one place. The additive includes 1) a compound selected from the group consisting of ferrocene and its derivatives represented by the following structural formula, where R and R are each independently hydrogen, alkyl, cycloalkyl, aryl, or heterocyclic; ) an organic carrier liquid in which the ferrocene (dicyclopentadienyl iron compound) is soluble;

The excess air supplied to the combustion furnace is controlled so as to support the combustion of pulverized coal to an acceptable level of emissions of carbon-containing particles at the desired combustion efficiency, by the use of additives: 1. The use of additives reduces the excess air supplied to the combustion furnace compared to the standard amount of air required for combustion without additives, and even with this reduction in air supply, Achieving the desired combustion efficiency and permissible content of carbon particles, 2. At the same time reducing the level of N08 emissions,
N without additives for the combustion of coal to achieve the desired combustion efficiency and permissible content of carbon particles.
This makes it possible to maintain lower than normal levels of Ox emissions.

The amount of additive used depends on several factors, including the quality of the coal, the coal feed rate, and the operating efficiency of the burner. The concentration of the additive injected into the fireball is determined based on the ppm of iron in the additive relative to the instantaneous amount of coal fed into the fireball. A practical lower limit for the amount of additive used is the minimum pp weight of iron required to produce a significant increase in combustion efficiency. A practical upper limit is the pp value at which even further increases do not significantly increase the combustion efficiency.
It's weight. An increase in combustion efficiency is usually 1%.
This ranges from an increase of about 99% to an increase of about 99%. In most cases, the amount of additive iron used will range from 0.5 ppm to 1100 ppm. If additives are injected into the fireball, soot emissions can be considerably reduced, at least by improving the efficiency of the post-stage combustion in the upper region of the fireball, while also reducing acceptable levels of NOx emissions. is maintained.

[Example] A preferred embodiment of the invention is shown in FIGS. 1-6.

Figure 1 shows a typical sketch of a coal-fired furnace.

Combustion furnace 10 has a firebox 12 that is on the order of 100 ft. by 100-150 ft. in height. A fireball 14 is formed within the firebox 12 of the combustion furnace, thereby generating heat, which flows upward in the direction of arrow 16. The heat is transferred to the heat exchangers 18, 20,
and taken away from the hot combustion gases at 22. The temperature of the combustion gas in the region of the heat exchanger 18 is between 1300 and 140
It is in the range of 0°C. In the area of heat exchanger 20, the temperature has fallen to approximately 700-800°C. In the heat exchanger 22, the temperature of the gas exiting from the heat exchanger is 300 to 400.
in the range of ℃. At the bottom 24 of the combustion furnace is an ash hopper 26. Similarly, the lower end 2 of the heat exchanger system
At 8 there is an ash hopper 30 for removing particulate matter that falls naturally as the combustion gases pass through the system. The combustion gases continue to move in the direction of arrow 32 and continue through duct 34 . Duct 34 conveys the gas to an electrostatic precipitator 36 having an electrostatic cell 38 . The ash removed there collects in an ash hopper 40 and is removed from time to time and transported by truck or similar. cooled to 120
A fan 42 is provided in order to raise the stack 44 in the direction of an arrow 46 and discharge the combustion gas (exhaust gas) which has reached a temperature of about .degree.

The fireball 14 is generated in the firebox 12 of the combustion furnace when pulverized coal introduced into that area ignites. Although not shown, a suitable natural gas burner is provided in region 48 to ignite the pulverized coal as it is introduced through nozzle 50.

Combustion air is introduced from a brenum 52 around the nozzle 50 to support combustion within the fireball 14. The pulverized coal is ignited by a natural gas burner in region 48 to create a fireball that, once formed, persists for as long as coal and air are supplied to the system. Pressurized air is supplied to the Blenheim 52 by a fan 54,
The fan admits air at 56. Pressurized air passes through channel 60 in the direction of arrow 58. Combustion air is heated by a rotary air heater 62. This F-heater is the flow path 3 of the combustion exhaust gas system 32.
4 and heats the incoming air as it passes through the rotary heater blades 64. Blenheim 52 maintains sufficient combustion air pressure to supply the required amount of air to the system.

Although not shown, air enters the system to provide slightly more than the theoretical amount of air needed to completely burn the carbon-containing materials and other nitrogen- and sulfur-containing compounds in the coal. A control device for controlling the amount of air may be provided at the nozzle 5o.

The coal supplied to the combustion furnace comes on a conveyor 66 and is put into a coal bunker 68. The coal is supplied from there to a coal crusher 7o. The coal crusher is connected to an air supply inlet 72 coming from a compressor 74, which removes a portion of the pressurized air in duct 76. The pulverized coal is supplied to the manifold 80 through the flow path 78 accompanied by pressurized air. A plurality of injection pipes 82 are provided, each of which has a nozzle 5.
Connected to 0. Pulverized coal is injected from nozzle 50 into fireball 14 to maintain the fireball.

As previously mentioned, the required combustion air is supplied into the brenum 52 and into the firebox 12, as will be described in more detail with reference to FIG.

As shown in the sectional view of FIG. 3, the firebox 12 of the combustion furnace 10 has three opposing side walls 84°, 86.
,92.94. In this embodiment, each side wall has multiple locations for introducing the pulverized coal and the air necessary to support its combustion.
For example, in the side wall 88 there is a pulverized coal injection line 82 with a nozzle 50 for feeding into the area of the fireball of the firebox.
There is also a Blenheim 52 that supplies air for oxidation. All other side walls of the furnace have similar provisions, and this is common practice in most coal-fired furnace operations. It is known that there are some combustion furnaces that burn much less coal and therefore require fewer places to introduce it. The system may also be operated by numbers.

As an example, the coal and air injection system is shown in more detail in FIG.
0 is located in the area of the side wall plane. The supply to the nozzle 50 is via a conduit 82, but the pulverized coal and air are supplied by the arrow 9.
It enters this channel in the direction of 6 and ejects from the nozzle into the fireball 14 in the direction of arrow 98. Also in the side wall 86, there is a nozzle 50 and a conduit 8 for feeding pulverized coal to the nozzle.
A similar facility with 2 is provided. It should be appreciated that a variety of nozzle arrangements may be used to introduce pulverized coal into the fireball. That is, what is shown in FIG. 2 is only one illustrative example of a variety of nozzles commonly used in coal combustion furnaces.

In the figure, the introduction of air required to maintain combustion in the fireball is also shown schematically. The blenheim, shown generally at 52, has a rear wall 100, a top wall 102, and side walls not shown. The blenheim contains pressurized air, which flows upward in the direction of arrow 58. 5. Nozzle conduit 82
is surrounded by a casing 104, which has an opening 108 in its end wall 106. Since the opening 108 is larger than the conduit 82, an annular groove is formed around the conduit 82.
108 is completed. This causes the pressurized air to flow through this annular opening to the surface 110, which is also annular, and from there to eject into the fireball in the direction of arrow 1.12.

Additives for improving the combustion of the supplied coal are stored in the storage tank +14. The outlet of this tank is at 116, and from there a flow path 120 leads to C pump 1.
The supply is made at 18. The outlet 122 of the pump is connected to the pipe 12
Connected to 4. Several branch pipes such as pipe 124, 6126, and 128 are branched. Branch pipe 128 is connected to a plurality of injection nozzles 130.

Branch pipe 128 acts as a manifold and has a plurality of channels 132 connected thereto for supplying a series of nozzles 130 . Nozzles +30 are located below each pulverized coal feed location in this example. As shown in FIG. 1, each wall of the combustion furnace has a plurality of pulverized coal injection nozzles 50, for example four, arranged longitudinally. In the embodiment shown in Fig. 2, one
Two injection nozzles +30 are located. However, depending on the loading of pulverized coal in the combustion furnace, the required number of injection orifices for the additive may be small in some locations, and the injection orifices ensure that the additive is delivered into the fireball. It is understood that they can be placed at any location on the wall of the furnace, as long as the location is such that the pulverized coal is It is also possible to position only one nozzle 130. Also,
It should also be appreciated that the location of additive injection nozzles does not need to be on every wall, depending on the amount of coal to be burned in the furnace to meet the desired capacity. In any case, 1181 cylinders are sufficient to supply all the nozzles arranged on the peripheral wall of the combustion furnace for injecting additives at selected locations. . Storage tank! 14 may have sufficient capacity for several hours of operation of the combustion furnace and can easily be supplied with additional additives if necessary. The additive includes: 1) a compound selected from the group consisting of ferrocene and its derivatives represented by the following structural formula, in which R and R are each independently hydrogen, alkyl, cycloalkyl, aryl, or heterocyclic; and 2) The ferrocene (dicyclopentadienyl iron compound) is an organic carrier liquid that is soluble and injectable at operating temperatures in the external environment of the combustion furnace as described above.

In formula I, alkyl means a branched or straight-chain alkyl group having from 1 to 10 carbon atoms, such as methyl, ethyl, propyl, n-butyl, hexyl or peptyl. Cycloalkyl means a lower cycloalkyl group having 3 to 7 carbon atoms, such as cyclopentyl or cyclohexyl. Aryl means an organic radical obtained by removing one hydrogen atom from an aromatic compound. The above compounds include substituted phenyls such as phenyl and lower alkyl substituted phenyls. These compounds include tolyl, ethylphenyl, triethylphenyl, herophenyl such as chlorophenyl, or nitrophenyl. Heterocyclic means pyryl, pyridyl, furfuryl and the like. The aryl or heterocyclic group generally contains up to 15 carbon atoms.

Dicyclopentadienyl iron is commonly called ferrocene. The compounds of formula I above are therefore considered to be ferrocene and its derivatives.

Preferred compounds of formula I include ferrocene(dicyclopentadienyl)iron, di(methylcyclopentadienyl)iron, di(ethylcyclopentajenyl)iron, methylferrocene, ethylferrocene, n-butylferrocene,
didecylferrocene, phenylferrocene, m-tri(
m-toly) ferrocene, didecylferrocene, dicyclohexylferrocene, and dicyclopentylferrocene. The organic carrier liquid is a type of liquid in which the selected dicyclopentadienyl iron compound is soluble. Furthermore, the carrier liquid is a liquid with a high flash point and a viscosity at operating temperatures such that it can be injected through the injection nozzle 130. Desirably, the flash point of the carrier liquid is greater than 74°F and the boiling point is greater than 95°F. The viscosity of the carrier liquid is typically less than 50 centipoise at 20°C, but may range from 0.3 to 3 centipoise at 20°C. Suitable organic carrier liquids or solvents, preferably in the centipoise range, may be of aromatic or hydrocarbon type; aromatic solvents include xylene, toluene, and So 1 10
Solbesol 100'' (manufactured by Imperial Oil) is a mixture of benzene and naphthalene with a flash point of about 100°F. Suitable hydrocarbons include alcohols such as hexanol and octanol. Other hydrocarbons include heavy oil, light oil, petroleum spirit, and the like. This type of solvent has a flash point associated with a low viscosity. These solvents are stable and the selected additives are soluble. Of course, the chosen solvent is non-toxic when burned.

It should be noted that the additive may contain various commercially available colorants to give it a distinctive color to distinguish it from other substances used in the operation of coal-fired furnaces. It is. Containers of additives must be explosion safe and should be handled appropriately. Tanks should also be suitably equipped to minimize the risk of explosion and fire.

In FIG. 4, a schematic diagram of one example of an electronic control circuit for controlling the injection amount (flow rate) of additive is shown. The controller 134 has a keyboard 136 and a ROM1.
It may be any standard type microprocessor, such as one programmed by its internal program contained in a 38.

Additionally, +40 RAM for additional programming instructions and storage of data created during daily driving.
is provided. Inputs to the controller come from a standard flow sensing device 142 located in the hopper to measure the pan flow rate of coal flowing into the crusher. The purpose of the flow rate detection device 142 is to periodically detect the flow rate of pulverized coal being fed into the combustion furnace at intervals of time. This information is provided to the controller via line 144. Keyboard 136 and ROM 138
Controller based on input information from the program inside! 34 produces a signal in line 146 that controls the output flow of pump 118. Those skilled in the art will appreciate that the signal in line 146 is necessary to deliver and inject the additive through the nozzle +30 at the desired flow rate. Any signal that sets a specific rotational speed of pump 118 such that a certain pressure is generated is sufficient.
For feedback purposes, a flow rate sensor 148 is provided in the piping 124, as shown in FIG.
Then: With its feedback loop, the controller can further adjust the speed of pump 118 to obtain the desired flow rate in line +24. All of the operations for adjusting the rotation speed of the pump 118 are as follows:
This is performed based on a program stored in the storage device of the controller 134.

The flow rate of coal to the combustion furnace is 25I2b/h to 170t/
It is in the range of h. The flow rate of the additive depends on the iron content in it, but the iron in the additive is always Ol, ~1100 ppp relative to the instantaneous value of the flow rate of coal fed to the combustion furnace.
Of course, there are cases where large amounts of additives are not necessary, and for most feed coal f weight, the amount of iron should be 0.1 to 5 ppm relative to the amount of coal. It is known that the amount of additive is usually sufficient. Therefore, the program in the memory of controller 134 provides the necessary controls to pump 118 to obtain the desired additive flow rate (per unit time) based on the known flow rate of coal feed into the system. conduct.

The system for measuring the flow rate of coal through the duct 7 may be any type of gravimetric device suitable for measuring the weight of the coal as it enters the hopper and then fed into the crusher, delivering the ferrocene additive. The preferred method for introducing the ferrocene additive into the burning coal, especially in large combustion furnaces, is by injection as described above, although a variety of other methods may also be used to introduce the ferrocene additive into the burning coal. Of course, for example, the ferrocene additive may be mixed into the pulverized coal before it is introduced into the combustion furnace, or it may be entrained in the air supplied to support combustion.

The obvious effect of injecting this type of additive is an increase in combustion efficiency, which in turn reduces soot and
This means that emissions of carbon-containing particles are reduced. Experimental results with this additive under practical industrial conditions indicate that soot reductions of up to 75% can easily be obtained. This dramatic effect is achieved even in high-performance combustion furnace systems with inherently very low soot emissions.
Commercially available under the trade name BONEX, its use results in distinct savings in fuel supply due to increased heat output. Improved combustion efficiency reduces fouling and corrosion, which improves heat transfer, extends equipment life, reduces maintenance costs, and minimizes disruption to plant operations. Other beneficial effects include reducing excess air requirements, reducing fan power to operate the soot blower, allowing lower quality and cheaper fuels to be used effectively, and reducing the amount of commercially available ash. The amount collected will increase. Carbonex
The use of sulfuric acid has the indirect effect of reducing the amount of acid-forming components produced during combustion, since the sulfuric acid produced during combustion is adsorbed by the soot and is generated by reactions on the carbon surface. Are known. When such acid-containing soot particles are discharged into the atmosphere, so-called acid smut fallout results. However, with the present invention, soot emissions are reduced and acid emissions are correspondingly reduced. Other benefits of using Carbonex result from reduced soot in emissions. That is,
Correspondingly, the amount of relatively small soot particles in the atmosphere is reduced. It is well known that particles smaller than 15 microns remain suspended in the atmosphere for long periods of time and are therefore inhaled by breathing. However, Carbo
The use of nex additives significantly reduces the emissions of relatively small soot particles from coal-fired furnaces.

To test the effectiveness of the additive according to the invention, a pilot plant scale coal-fired furnace was used with appropriate hardware for testing emissions. Combustion performance was measured by analyzing the following emissions in exhaust gas.

Carbon dioxide (CL), -carbon oxide (CO), oxygen (0□
), nitrogen oxides (NOx), sulfur dioxide (SO□), and particulate matter (RO,). The following analytical method was used to measure these values in the exhaust gas. Non-dispersive infrared method to measure CO and CL emissions, paramagnetic method to measure 03 concentration, chemiluminescence method to measure NOx emissions, and pulsed fluorescent 1 particulate matter measurement to measure SO3 emissions. 5 tan-derds of
Performance for New 5tati
onarySources”Federal Re
gister 36. No, 247.24876°19
Method "5" of the December 23, 1971 edition was used.

What are the characteristics of particulate matter? Amount of particulate matter carbon content ash content Particle size distribution It is.

A pilot plant scale combustion furnace with an average of 600~
It was operated at a load of 700kBTtl/hr. Of course, the problem is that the operation of this device is +000x 10'B
The question is whether the operation is comparable to that obtained in a utility-scale combustion furnace fired at loads of TU/h+- or more. Previous experience has shown that there is a fairly close relationship between laboratory scale or pilot plant scale burners and utility scale combustion furnaces in terms of the effect of additives on combustion efficiency. ing.

To confirm the effectiveness of the additive according to the invention, it was tested using a representative sample of coal.

Coal has the characteristics shown in Table 1 below.
-Created calorific value (Btu/Ib, dry) Industrial analysis (wt%, dry) Volatile matter fixed carbon ash Elemental analysis (wt%, dry) Carbon Hydrogen Nitrogen Sulfur Yellow Oxygen Ash 12.779 41.38 4B, 59 10.03 70.42 5.07 4, Ol 9.14 10.03 It is believed that the organic carrier liquid has the ability to influence the overall fuel process. Therefore, we first conducted a test using a sample carrier to see how much, if any, it would affect combustion efficiency. In this example, the carrier liquid used was xylene. The additive consisted of iron in ferrocene dissolved in a xylene carrier at a ratio of 5000 ppH by weight to 11. This additive was diluted to the appropriate iron concentration required in the coal-fired furnace. That is, tests were conducted on cases in which xylene contained and did not contain ferrocene, and the results obtained are summarized in Table 2 below.

/ / The first column (column), that is, the case where the iron is Oppm but the carrier (xylene) is added to the coal, is considered the baseline combustion, and the other cases where Feceron is used are compared with this. Ru. Therefore, the overall efficiency before additive injection is recorded in this column.

When compared to the results obtained using xylene alone, it is clear that the Carbonex additive containing ferrocene produces a significant effect in reducing carbon in the granular ash. Compared to the results for xylene alone, at 1 ppm iron in Carbonex, the carbon in the granular ash is reduced from 3.1 wt% to 2.8 wt%. Ca sprayed into the flame
Increasing the concentration of rbonex to a level of 5 ppm iron in ferrocene resulted in zero carbon in the granular ash.
．． It has decreased to 11wt%. As a result, the combustion efficiency was 99.62% in the case of only xylene, whereas it increased to 99.88% in the case of Carbor+ex.

The following table shows an analysis of the results obtained with the change in combustion performance.

Table 3 Regarding the effect of G on the combustion of bituminous coal αm1) OneX on the variation in combustion performance depending on the iron level According to the above analysis, the following effectiveness is confirmed. That is,
Carbonex injection into coal flame
When the iron in the rbonex was changed from 1 ppm to s ppm, the carbon in the granular ash was clearly reduced from -10% to -74%. As a result, the combustion efficiency is increased by 0.26% compared to the combustion efficiency when Carbonex iron is at 5 ppm of Carbonex iron injected into a flame of 0 coal. , the amount of ash increased by 72%, the average particle size increased by 11%, NO.

emissions have increased by 310 ppi.

Increasing the usage of Carbonex will increase NOx emissions, which will exceed acceptable limit levels. Therefore, if you lower the air supply level, NO
Suggestions were made that l emissions would return to acceptable limit levels. As a result of the test, the level of excess air was 26
% to 10%, it was found that NO-Y emissions were reduced to the permissible limit level as seen in Table 4 and Figure 5. But this is truly surprising. It is believed that the presence of the additive according to the invention takes effect so that the amount of oxygen required to oxidize the carbon particles is considerably reduced and therefore there is an excess of oxygen to oxidize the nitrogen components. It is from. Therefore, the required amount of air can be eliminated while reducing NOx emissions and still maintaining a high oxidizing power for oxidizing carbon particles.

In the past, in typical coal-fired utility boiler operation, N08 emissions were seen to be proportional to the amount of excess air in the system. On the one hand, the carbon content and carbon particulate matter are inversely proportional to the excess air content [this is because 'P
rog, in Energy and Combusti
A, F. Sarofim and R. C. Flaga on Sci, 2:1-25, 1976.
“NO.

control for 5tationary Co
mbustion 5 sources and 197 of the same magazine
According to "Inefficiency and Emission Reduction in Large American Steam Generators" by B. P. Breen and J. C. 5otter, published in 1998, 4+210-220], therefore the consequence is that excess air This means that if J408 emissions decrease, the amount of carbon-containing particulate matter should increase.

Operators of coal-fired practical boilers are required to use coal-fired boilers for two reasons: to meet standards for the prevention of air pollution due to NOx, and to ideally improve overall plant efficiency without sacrificing combustion efficiency. You will want to reduce excess air. Unfortunately, as the operator reduces the excess air for combustion, combustion efficiency begins to decline before the desired NOx emissions are reached, resulting in a visible rise in black smoke. High levels of particulate carbon are produced. Indeed, surprisingly, the use of additives according to the invention in the process of combustion of pulverized coal becomes a means of making it possible to maintain a high level of combustion efficiency at low levels of excess air.

To investigate the effect of Carbonex ferrocene additive in coal, two levels of excess air were used;
With and without Carbonex,
A wide range of combustion performance characteristics were measured and tested. The results of these tests are summarized in Table 4 below and are shown graphically in FIG. The standard deviation measurement values of various characteristic values of combustion performance in Table 4 are as follows.

0% ± 2% CL ± 2% CO ± 3% NOx ± 2% Hydrocarbon ± 2% Particulate matter ± 5% Combustion efficiency C
It is determined based on the degree of O□.

Table 4 Results of combustion tests with injection of carbon, x As is known from the data shown in Table 4, feeding Carbonex as an additive to the combustion In some cases, it has the effect of increasing combustion efficiency. i.e. 98.35% to 99
．． 30%, which has increased from 99.62% to 99.88%. As combustion efficiency increases, there is an increase in NOx production and a decrease in carbon in particulate ash. Unexpectedly, when reducing the excess air from 26% to 10%, the N
The increase in Ox-c mission is reduced to a level comparable to using xylene alone with 26% excess air, while the combustion efficiency does not fall below an acceptable level of 99.00%. What can be inferred from the findings is that
Carbon as a coal combustion additive to maintain combustion efficiency without sacrificing environmental air quality with respect to NOx emissions when excess air levels are low.
ex can be used.

What can be inferred from the data shown in Table 4, No. J.

If Carbonex is combined with 10% excess air, 26% excess air will produce a flame with properties similar to those of the xylene-only, ie, reference flame.

The NOx emissions are almost the same for both of these flames.
The emissions of incomplete combustion products will be similar and the levels of combustion efficiency will be similar.

This unexpected finding that when excess air levels are low, Carbonex can be used as a coal combustion additive to maintain combustion efficiency without sacrificing environmental air quality in terms of emissions. This makes it possible to take advantage of the physical properties of the flame and burner system.

In any burner system, combustion of carbon occurs under different reaction conditions depending on where the carbon particles are located in the flame. The hottest part of the flame is the core, which has a lot of fuel and therefore has little excess air.

The temperature of the flame decreases with a certain gradient from the hottest region of the flame toward the edges of the flame, and along this decreasing temperature gradient, the availability of air gradually increases. .

Therefore, the stages of combustion can be distinguished as follows: a) from a fuel-rich stage with relatively little excess air at high temperatures, i.e. a reducing flame;

b) ranges from a relatively air-rich near-rich stage where the temperature decreases, ie to the oxidation flame.

Knowing the distinction between these two stages of combustion makes it possible, at least theoretically, to create a staged combustion system that takes advantage of the differences in temperature and the amount of excess air at the various stages of combustion.
, which opens up the possibility of construction in known ways to reduce emissions. However, in practice, the use of staged combustion as a means to reduce NOx emissions has been shown to increase particulates and other incomplete combustion products and reduce NOx emissions.
We have not been successful in breaking the link with the reduction in x emissions.

By using Carbonex additives according to the present invention, industrial scale coal combustion furnace systems can be operated successfully. FIG. 6 shows an enlarged sectional view of a portion of the burner of the combustion furnace. Pulverized coal is supplied to manifold 80 via main flow path 78 . A plurality of coal injection lines 82 deliver coal to the injection nozzle 50 so that the coal is fed to the fireball as previously described with respect to FIG.

Air is supplied around each nozzle 50 to support the combustion of the coal injected to maintain the fireball. The amount of excess air supplied along the height of the fireball 14 is controlled to achieve combustion in a single stage, the details of which are explained in more detail in FIG. Fireball lower area 160
A relatively small amount of excess air is supplied to create a reducing flame region. More excess air is introduced in the upper region 162, where an oxidizing flame region is created. fireball 14
2 The amount of excess air introduced is such that the transition from reducing flame to oxidizing flame in is continuous.

The number is gradually increased from the lower region F1+60 to the upper region 162.

In order to achieve the above-mentioned gradual increase in the amount of excess air at each of the injection nozzles 50 depending on the position of the injection nozzle, it is necessary to change the air supply system. That is, the compressed combustion air coming from the compressor 74 is transferred to four independent tacts 164, 166, 168
8 and 170. Duct 164.166.1
6a i3 and 170 are each provided with flow control valves 172, 174, 1768 and 178. Preferably, these air control valves are electronically actuated to control the amount of air delivered to the injection location of each nozzle, with electronic control being provided by controller 134. The control program for this controller is configured to provide excess air needed at each injection location 50 based on other inputs to achieve staged combustion from the reducing flame region to the oxidizing and quaternizing flame region. It has become.

In other words, the controller adjusts the openings of valves 172, 174, 176 and 178 according to the detected coal supply conditions so that the exact proportions of excess air required at each stage of the combustion process are provided. For illustrative purposes, these proportional valves are set to 11 for the lowest air level.

%, first intermediate [13% at 0, 17 at second intermediate stage
%, the lowest level is set to 20%.

Carbonex additives have made staged combustion a viable and useful combustion method. In areas where air levels are low, the presence of Carbonex additives increases combustion efficiency while maintaining acceptable NO and emissions levels. This improves the overall combustion at this stage by increasing the combustion efficiency in the reducing flame, resulting in less soot,
Less incomplete combustion products are emitted as smoke and other pollutants. At the same time, the lack of oxygen at this stage prevents the formation of Noa.

When the remaining particulate carbon enters the oxidizing region of the flame,
Excess air can be increased to help oxidize the remaining particulate carbon. ``Excess air injected on the fourth floor does not pose a risk with respect to the R90.
By using bonex additives, a staged combustion system can be established that has the advantageous advantages of increasing combustion efficiency and reducing the generation of incomplete combustion products without increasing the formation of NOx. .

Evidence supporting the use of Carhonex in staged combustion systems can be found in Table 5 below. The data shown in FIG. 5 was obtained with one detuned burner system. As will be appreciated, a detuned burner system approximately creates reaction conditions similar to those in the staged combustion described above.

As shown in the data in Table 5, in a coal flame with xylene carrier injection, when reducing the swirl of secondary combustion air and increasing the average coal particle size, N
08 Emissions are reduced and the overall average particle size is increased2
The amount of particulate matter increases and the combustion efficiency decreases. These changes appear to be more or less a function of excess air.

Injecting 5 ppm Carbonex iron into a detuned or larger grain size high volatile bituminous coal flame increases NOx emissions and reduces overall average particulate size.

Particulate content is reduced and combustion efficiency is increased. These changes are offset by changes caused by detuning the burner or grinding the coal to a larger particle size.

If Carbonex is injected so that the iron ratio is 5 ppar in a low-degree vortex or large-grain coal flame, and the excess air is reduced from 20% to 10%, the combustion efficiency will reach a level of 98%. Net NO while being maintained
□Mr. Makoto Lee accounted for approximately 25%.

In summary, these tests demonstrate that this additive is effective as a coal additive. This additive appears to be active in combustion under reducing conditions. Therefore, this additive can be used to improve combustion efficiency in staged or detuned combustion devices. The advantage provided by this technique is that it makes it possible to reduce NOx emissions while maintaining combustion efficiency within acceptable limits.

So (: a'rbonex additive makes it possible to use the principle of stages of combustion, such as a staged combustion system or a detuned combustion system. Without Carbonex additive, such a combustion system would reduce NOx emissions However, adding Carbonex to pulverized coal fuels could not be a useful system for reducing emissions because particulate emissions as soot and smoke would be greatly increased. Solving the particulate emissions problem while maintaining acceptable NOx emissions levels provides many environmental benefits and economic benefits, which were unexpected. This is a result, because all previous studies taught that the basic law of combustion is that if NOM emissions decrease, incomplete combustion products increase.The effective amount of oxygen and Ca
Having discovered the surprising results that the combustion efficiency and pollutant emissions can be controlled by adjusting the amount of rbonex additive accordingly, various steps have been taken to implement and apply this technological innovation in industry. Specific implementations can be envisaged. The way to make it concrete is to write the whole frame
burner systems, staged combustion, and swirl
Other embodiments of vine burner systems in which the present invention may be utilized will be readily apparent to those skilled in the art, such as ed) combustion (also known to those skilled in the art as detuned combustion).

Although the preferred embodiments of the present invention have been described in detail above, it is understood that various modifications can be made without departing from the spirit of the present invention or the contents described in the claims.
Those skilled in the art will understand.

[Brief explanation of drawings]

Figure 1 is a schematic diagram of a coal-fired furnace with an emission removal system; Figure 2 is a cross-sectional view of a portion of the furnace wall showing the locations of injection of pulverized coal, air and additives; Figure 3 is similar to Figure 1. FIG. 4 is a schematic diagram of an electronic control system for determining the amount of additive injection. Figure 5 shows that combustion efficiency and NOx emissions are not as high as C.
A diagram showing the effect of arbonex and excess air, FIG. 6 is an enlarged schematic diagram of the burner section of the combustion furnace. ID... Combustion furnace, 14... Fireball, 50... Pulverized coal nozzle. 52... Blenheim, ilo... Excessive air port (annular space), 130
...Additive injection nozzle. Japan G, 5゜(O/,) Procedural amendment (method) % formula % 1. Indication of case 1999 Patent application No. 144291 2. Name of invention Method for combustion of carbon-containing materials in a furnace 3. Amendment Relationship with the patent applicant Sea Hawk Corporation 4 Agent name Patent attorney (7021) Wakabayashi 5 Date of amendment order: September 26, 1999 Tadashi

Claims (1)

[Claims] 1. At least one place for feeding pulverized coal into the furnace in order to form and maintain a fireball in the furnace, and pulverized coal in the fireball. 1. A method for improving combustion efficiency in a coal-fired furnace having at least one location for introducing air to support combustion, while maintaining emissions of NOx produced by the combustion at an acceptable level, the method comprising: An effective amount of an additive is placed in at least one location to control the amount of excess air required to support the combustion of pulverized coal, significantly improving combustion efficiency while maintaining NOx emissions at acceptable levels. The additive has the following structural formula ▲ mathematical formula, chemical formula, table, etc. ▼ where R and R' are each independently hydrogen, alkyl, cycloalkyl, aryl or heterocyclic; b) an organic carrier liquid in which the ferrocene (dicyclopentadienyl iron compound) is soluble; (2) the combustion furnace; supporting the combustion of pulverized coal while maintaining acceptable levels of emissions of carbon-containing particles at a desired combustion efficiency by controlling the amount of excess air supplied to the
In this case, the use of an additive a) reduces the amount of excess air supplied to the combustion furnace compared to the standard amount of air required for combustion without the additive, and achieves the desired combustion efficiency. b) simultaneously reducing the level of NOx emissions to achieve said desired combustion efficiency and permissible content of carbon particles and for the combustion of said coal; NOx without additives
A method of combustion of carbon-containing materials in a furnace, comprising: maintaining emissions at a level lower than that of . 2. By controlling the introduction of excess air into the fireball, combustion is caused in stages in the fireball, and the additive is added to the reducing flame region of the fireball, which has a reducing flame region and an oxidizing flame region. Claim 1: The combustion of the carbon particles is activated by introducing
The method described in. 3. The method of claim 1, wherein the iron in the additive is injected into the fireball in the furnace at a rate of about 0.1 to 100 ppm based on the amount of coal fed to the furnace. 4. The method of claim 3, wherein the iron in the additive is injected into the fireball at a rate of about 1-5 ppm. 5. The dicyclopentadienyl iron compound mentioned above is dicyclopentadienyl iron, di(methylcyclopentadienyl) iron, di(ethylcyclopentadienyl) iron, methylferrocene, ethylferrocene, n-butylferrocene. ,
5. The method of claim 4, wherein the method is selected from the group consisting of dihexylferrocene, phenylferrocene, m-triperrocene, didecylferrocene, dicyclohexylferrocene, and dicyclopentylferrocene. 6. The method according to claim 5, wherein the compound is dicyclopentadienyl iron. 7. The method of claim 6, wherein the carrier liquid is selected from the group consisting of high flash point aromatic solvents, hydrocarbon solvents, and petroleum-based solvents. 8. The solvent is xylene, toluene, hexanol,
8. The method of claim 7, wherein the method is selected from the group consisting of octanol, kerosene, heavy oil, petroleum spirit, and Solvesol 100T^M. 9. The method of claim 7, wherein the solvent has a viscosity in the range of 50 centipoise or less at 20<0>C. 10. The method of claim 9, wherein the viscosity of the solvent at 10.20<0>C is in the range of 0.3 to 3 centipoise.