KR20130047811A

KR20130047811A - Gas generating method and gas generating device using green coal

Info

Publication number: KR20130047811A
Application number: KR1020110112416A
Authority: KR
Inventors: 손달호
Original assignee: (주)원진월드와이드; 주식회사 경동
Priority date: 2011-10-31
Filing date: 2011-10-31
Publication date: 2013-05-09

Abstract

The present invention relates to a gas generating method and a gas generating apparatus using green coal, and more particularly, to a gas generating method and a gas generating apparatus using green coal which can generate coal gas using green coal having a small particle size.
Gas generation method using the green coal of the present invention, mined raw coal (non-coking coal: water 15% by weight or less, anhydrous reference calorific value 6000 Kcal or more, volatile matter 35-40% by weight, ash content 10% by weight, sulfur content 0.5% by weight Drying the following); Manufacturing green coal through a pyrolysis process by heating the non-coking coal at 500 to 800 ° C. under an air-blocking sealed condition; And producing a combustible gas by incomplete combustion of the green coal.

Description

GAS GENERATING METHOD AND GAS GENERATING DEVICE USING GREEN COAL}

The present invention relates to a gas generating method and a gas generating device using the green coal. More specifically, the present invention relates to a gas generating method and a gas generating apparatus capable of generating coal gas using green coal having a particle size of 20 mm or less.

Coal has occupied more than 24% of the world's energy sources until recently, but its use is gradually decreasing in Korea, unlike advanced countries, due to the negative view that it is not environmentally friendly due to the emission of environmental pollutants.

However, as the price of crude oil has recently risen and the current technology has reached the limit that it is difficult to secure new energy sources such as solar energy and bioenergy that can replace crude oil, the utilization of coal is being expanded. to be.

Coal is widely distributed all over the world and can be expected to be stable in the long term. Moreover, considering the current increase in demand, it has abundant resources and thus has the advantage that it can be used for a longer period of time than the current reserves.

Currently, coal relies on imports for most of the bituminous coal used in the industry, except for small amounts of anthracite coal produced in Korea. Imported bituminous coal requires a separate heat source for initial ignition when used in a heater such as a farmhouse, and it is not easy to adjust thermal power, and it is not easy to change the temperature of the heater according to the greenhouse temperature. Therefore, in view of economics and supply and demand stability of logistics, it is urgently required to develop new coal raw materials to replace bituminous coal.

In particular, bituminous coal, anthracite coal, and the like were used as raw materials for the coal gas generation furnace using coal, but all of these raw materials had a problem in that only a standard of 25 mm or more in size could be used as raw materials. This is because when a raw material having a particle size of 25 mm or less is used, fine ash forms after combustion to block the air supply unit of the coal gas generating furnace, and thus the operation of the coal gas generating furnace becomes impossible. In addition, when bituminous coal is used, there are environmental pollution problems in which noxious gas and tar are generated. In the case of anthracite coal, it is expensive and difficult to obtain, and there is a problem that it takes some time for initial ignition.

As a result, most of the existing coal gas producers have regulated the particle size specification of raw materials to 25 ~ 80 mm, which means that the smaller the particle size of the ash is, the smaller the particle size of the ash is. This is because if the value is small, the air injection port (air supply part) of the air conveyed by the blower is blocked to block the supply of air required for combustion.

The present invention is to solve the conventional problems as described above, and to provide a gas generating method and a gas generating apparatus using green coal to prevent the clogging phenomenon of the air supply even when using a fuel having a particle size of 20mm or less. do.

In order to achieve the above object, in the present invention, by incomplete combustion of the green coal of 1% by weight or less, 3 to 20% by weight of volatile matter, 15% by weight or less of ash, 70 to 85% by weight of fixed carbon, 0.5% by weight or less of sulfur, Generate gas.

On the other hand, in the specification of the present invention, the term 'below' is preferable when the value is less than or equal to the upper limit defined in the specification, and it is described as meaning that the technical significance of the present invention is limited only by the limited upper limit, and the lower limit is more than 0 (that is, even if a trace amount is necessarily Included).

Green Coal Manufacturing Process

The green coal is made of raw coal and has a moisture content of 15 wt% or less, a calorific value of 6,000 Kcal / kg or more based on anhydrous standards, and 35 to 40 wt% of volatile matter, 10 wt% or less of ash, and 0.5 wt% or less of sulfur powder. It is manufactured using.

In order to achieve the above object, in the present invention,

Drying the mined raw coal (non-coking coal: moisture 15 wt% or less, anhydrous reference calorific value 6000 Kcal or more, volatile matter 35-40 wt%, ash 10 wt% or less, sulfur content 0.5 wt% or less);

Manufacturing green coal by subjecting the raw coal to heat and pyrolysis at 500 to 800 ° C. under airtight sealing conditions; And

Incomplete combustion of the green coal to produce a combustible gas.

The green coal production process of the above process will be described in more detail. First, coal mined includes adhesion moisture, intrinsic moisture, and bonding moisture, and thus, a process of drying the coal should be performed. At this time, the adhered moisture is mechanically attached to the coal, and refers to the moisture that is evaporated and disappeared when the coal is thinned indoors and dried at room temperature. Intrinsic moisture is due to the colloidal hygroscopicity of coal, and refers to moisture that is lost when dried at 105 ° C. after removing the adhered moisture. Bound moisture is moisture in chemically bound form and refers to moisture released at about 300 to 500 ° C. when coal is dried without being evaporated at 105 ° C. The water content of coal in this moisture is the sum of the adhesion moisture and the intrinsic moisture. Coal is usually added artificially with a certain amount of water to prevent dust blowing during transportation, usually with a water content of 5-15% of the total weight of coal.

Specifically, in the present invention, the mined coal containing a certain moisture as described above is spread out thinly in a large space, and dried naturally or using a facility such as a rotary dryer using steam, that is, a proper moisture content, that is, 5 to 15% by weight of moisture, preferably The non-coking coal is dried to have 5 to 7% by weight.

At this time, if the moisture content exceeds 15% by weight in the coal drying process, the temperature rise in the furnace is delayed due to the use of a heat source for initial excessive moisture evaporation, so that the thermal decomposition rate such as the removal of volatile components is lowered and the green of the target quality within a certain time. Coal cannot be obtained. In addition, when the moisture content is less than 5% by weight, it is difficult to not only environmental aspects but also worker's work due to fine powder flying during transportation and charging.

Subsequently, green coal is manufactured by heating raw coal having an appropriate amount of water content under air-tight sealing conditions at 500 to 800 ° C. using an energy-saving rotary kiln system of indirect heating method under a sealed structure. At this time, when the heating temperature is less than 500 ℃, there is a problem that it is difficult to expect the effect of reducing the generated gas during combustion by the presence of a large amount of volatiles are not removed, if the excess amount of volatiles is removed when it exceeds 800 ℃ There is a difficulty in ignition of the combustion of coal raw materials, and there is also a problem that is not economical due to rising fuel costs.

Specifically, the raw coal having an appropriate amount of water is charged into the rotary kiln inlet charging hopper, and the charged dry raw coal is continuously transferred into the kiln (part of the rotary kiln in the combustion chamber) through a screw feeder. The pyrolysis process of raw coal is performed by indirect heating method by composing a combustion chamber composed of iron case, refractory, and burner outside the rotary kiln. The pyrolysis process according to temperature during the low temperature drying of raw coal charged into the rotary kiln is as follows.

(1) 25-100 ℃: During the natural drying process, most of the adhering water is removed, and some remaining adhering water and intrinsic water evaporate. Moisture is most separated at 60-80 ° C, evenly separated little by little above 80 ° C, and almost stops at 105 ° C.

(2) 100-200 degreeC: Separation of the occlusion gas (hydrocarbon) absorbed in solid inside occurs.

(3) 200 ~ 300 ℃: Decomposition of less coal such as lignite begins. Upon decomposition, bound water, CO ₂ and CO are separated in the oxygen compound, and H ₂ S is separated in the organic sulfur compound.

(4) 300 ~ 400 ℃: Coal decomposition of bituminous coal and anthracite coal begins. Coking coal is first melted and decomposed at 310 to 320 ° C, and after decomposition, gases such as H ₂ O, CO ₂ , CO, and H ₂ S and red tar and hydrocarbons having low viscosity start to separate.

(5) 400 ~ 500 ℃: NH ₃ begins to decompose from nitrogen oxides, and tar separation occurs most vigorously. Minerals also begin to decompose, and CO ₂ begins to separate from CaCO ₃ .

(6) 500 ~ 600 ℃: The generation of H ₂ O, Co gas is stopped, C _m H _n , H ₂ and CH ₄ are separated vigorously, and tar is continuously separated.

(7) 600 to 700 ° C: C _m H _n is decomposed to generate CH ₄ , a part of tar is decomposed to become a gas, and a part is converted to aromatic.

(8) 700 ~ 800 ℃: H ₂ and CO are generated by pyrolysis of C _m H _n gas and tar. The gas generated during the pyrolysis of the raw coal is transferred back into the combustion chamber along the gas line and used as a heat source for coal pyrolysis, thereby reducing fuel costs. As the rotary kiln rotates, the raw material in the furnace slowly moves in the direction of the exit and exits the kiln (part of the rotary kiln inside the combustion chamber) through a screw feeder, just as it is installed at the inlet.

At this time, the present invention further requires the step of cooling the coal heat-treated in the kiln (rotary kiln portion inside the combustion chamber) after manufacturing the green coal to a predetermined temperature or less to prevent spontaneous ignition before being discharged to the outside. The rotary kiln portion (outlet) outside the combustion chamber is surrounded by cooling equipment such as a water cooling jacket, thereby cooling the temperature of the discharged coal below 50 ° C. Subsequently, the green coal cooled by cooling equipment such as a water cooling jacket is discharged to the outside through a rotary valve provided at the lower end of the rotary kiln outlet.

The raw coal, which has undergone the above series of processes (drying, pyrolysis, cooling), has a calorific value of 7000 kcal / kg or more, moisture content of 1 wt% or less, volatile matter 3-20 wt%, ash content 15 wt% or less, fixed carbon 70-85 wt%, It is made of green coal having a sulfur content of 0.5% by weight or less.

<Gas Generation Process>

Coal gas is produced using green coal prepared in the manner described above. At this time, a coal gas generator 10 (see Fig. 2) is used, which is a facility that generates combustible gas using coal as a raw material and air and water vapor as a vaporizing agent. In other words, it is a device that converts combustion energy of coal into chemical energy sources (CO, H ₂ ). The principle is to produce a combustible gas containing carbon monoxide (CO) and hydrogen gas (H ₂ ) as main components by supplying high temperature water vapor (H ₂ O) to an environment where coal is burned and causing coal to be incompletely burned. Thereafter, a purification process is performed to remove harmful gases CO ₂ , SOx and NOx from the combustible gas. After this refining process is completed, it is possible to produce chemical products such as H ₂ SO ₄ or NH ₃ , chemical raw materials or raw gas as by-products.

The gas generating method and the gas generating apparatus using the green coal of the present invention can provide the following effects.

(1) Since green coal produced by pyrolysis of bituminous coal is used, the harmful gases generated during the combustion of bituminous coal are treated first, which greatly reduces the amount of environmental pollutants, has high heat, high ignition and combustion efficiency, and low specific gravity. Almost no caking And the high porosity of the green coal provides an effect of preventing the clogging phenomenon of the air supply unit provided in the furnace.

(2) Since the coal gas generator uses green coal having properties that are not available in the existing bituminous coal or anthracite coal, it reduces the particle size of raw materials in the coal gas generator and expands the range of available coal. It can also provide the effect of minimizing the emission of harmful substances.

1 is a manufacturing process diagram of a gas generating method according to the present invention; And,
2 is a view showing a gas generating device according to the present invention.

Hereinafter, although an Example demonstrates this invention concretely, it is not limited to these Examples at this invention.

I. Manufacture of Green Coal

Examples 1-12 and Comparative Examples 1-6

Manufactured with mined bituminous coal (non-coking coal) (10% moisture, 35.40% volatilized ash, 8.21% ash, 8.21% ash, 56.39% fixed carbon, 0.48% sulfur) and naturally dried for more than 24 hours to produce 5% moisture content. It was. Prior to charging the raw material, the rotary kiln was heated to a firing temperature at a rate of 5 ° C./min. After the temperature of the rotary kiln was completed, dry bituminous coal (non-coking coal) contained in a ton bag was charged into the rotary kiln inlet charging hopper at 400 kg per hour. The charged coal was transferred into the kiln through a screw feeder. At each test firing temperature, the pyrolysis was performed for a period of time while changing the holding time of the furnace by adjusting the rotation speed of the rotary kiln. After the pyrolysis was completed, the green coal obtained through the rotary valve was discharged to the outside after cooling to 50 ° C. or less by a water cooling jacket provided outside the rotary kiln outlet. At this time, the amount of green coal discharged to the outside was adjusted to 240kg per hour. The quality of the green coal obtained under each pyrolysis condition is shown in Tables 1 and 2 below. At this time, moisture, volatile matter, ash, and fixed carbon of green coal were calculated by industrial analysis method, sulfur by C / S analysis, and calorific value by industrial analysis result. In addition, the number of samples used for each analysis was set to 10 EA, and the average value was shown.

[Table 1]

[Table 2]

As shown in Tables 1 and 2, when the raw coal (coal briquettes) is heated and pyrolyzed at 500 ° C. or lower, volatiles are not removed, and thus a large amount of volatiles are hardly expected. In addition, when the raw coal (coal briquettes) is heated and pyrolyzed at 800 ° C. or higher, excess volatiles may be removed, which may cause difficulty in ignition in subsequent combustion.

II. Coal gas production from green coal

In the present invention, the coal gas is generated in the coal gas generating furnace using the green coal manufactured by the above process. Various facilities may be used as the coal gas generator, and the coal gas generator illustrated in FIG. 2 may be used.

Coal gas production method is the same as the method shown in FIG. That is, the step (S10) of providing the bituminous coal as a primary raw material, the pyrolysis (S20) by performing a reduction reaction on the primary raw material (S20), the manufacturing of green coal as a secondary raw material (S30), green coal as a secondary raw material Gasification by incomplete combustion in the gas generating furnace 10 (see FIG. 2) (S40), producing CO and H _{2 which} are combustible gases (S50), and purifying the produced gas (S60). .

At this time, green coal, which is a secondary raw material, can generate gas even with a fine particle size of 20 mm or less. However, if it has a particle size of 5.6mm or more, the air supply is not blocked and gas is continuously generated.

Table 3 below is a table showing examples of 'coal gas generation process using green coal' and 'coal gas generation process using soft coal' according to the present invention. When using green coal, the case where 100 weight% of green coal was used, and the case where only 30-40 weight% was mixed (the rest is bituminous coal) were shown. In the case of bituminous coal as a comparative example, the raw material particle size was tested to 20 mm or more as specified by the equipment manufacturer, and when using green coal as an example of the present invention, the test was conducted to 5.6 mm or more.

[Table 3]

As shown in the above table, the amount of gas generated in the embodiment containing 30% by weight or more of green coal having a particle size of 5.6 mm or more (that is, having a particle size of 20 mm or less) was not substantially different from that of the comparative bituminous coal. .

Referring to Figures 1 and 2, in the gas generation method according to the present invention will be described in detail 'gasification / incomplete combustion step (S40) to purification step (S60)' as follows.

Before supplying the green coal to the gas generator 10, first, the gas generator 10 is initially operated. In this case, after the auxiliary heat source such as wood or oil is put into the gas generating furnace 10, it can be combusted, and the combustion atmosphere composition and water vapor of the raw coal are generated in advance for a predetermined time to generate flammable gas quickly. Is preferred. Thereafter, before charging the secondary raw material green coal (100% by weight) or a mixture of green coal and bituminous coal into the hoppers 11a and 11b, the fine powder is separated through the screen. This is because when the fine powder is large, the operation efficiency is lowered. At this time, a screen for separating fine powder of about 5.6 mm or less can be used, and in this case, the particle size of the secondary raw material is 5.6 mm or more.

Thereafter, the secondary raw material is introduced into the gas generator 10, and the 'gasification / incomplete combustion step S40' is performed. At this time, the water in the steam tank 15 is made into steam by using the high heat generated in the gas generating furnace 10, and the steam is charged together with the air in the lower portion of the gas generating furnace 10 again. This is for use as a gasifying agent for generating hydrogen gas.

CO and H ₂ gas, which is a product generated in the gas generator 10, is discharged to the outside of the gas generator 10, and after dust is removed from the cyclone 20, the sinter plant or the boiler 40, 42, 44 Used as ignition fuel. Ash generated after incomplete combustion in the gas generator 10 is discharged to the outside through the ash tray (14, ash tray).

III. Gas generator

Finally, a gas generator using green coal according to the present invention will be described with reference to FIG. 2. Gas generating apparatus using the green coal according to the present invention includes a gas generator 10, cyclone (20; cyclone), valves 32, 34, refining equipment 35, burner 40 or boiler 42 , 44) may be further included.

First, the gas generator 10 is configured to be a space in which fuel containing green coal is incompletely burned, and has a substantially hollow cylindrical shape. On the bottom surface of the gas generating furnace 10 is provided a grate 12 projecting upward in the shape of a hat, which includes a plurality of air inlets (not shown), and the air is gas It is a structure which supplies to the generating furnace 10 inside. An ash tray 14 capable of discharging ash generated after incomplete combustion to the outside is provided at the lower portion of the gas generator 10.

The hoppers 11a and 11b for supplying fuel are provided at the upper portion of the gas generating passage 10. The hopper is composed of an upper hopper 11a and a lower hopper 11b to prevent the backflow of the gas generated in the gas generator 10 to maintain a constant pressure in the gas generator 10, two hoppers 11a, It is preferable that the fuel supply amount to the gas generating furnace 10 can be easily adjusted by adjusting the opening amount of 11b).

One side of the gas generator 10 is provided with a steam tank (15). The steam tank 15 stores a predetermined amount of water, and may ① supply water to the gas generator 10 through the water supply pipe 15b, and ② the gas generator 10 through the steam discharge pipe 15a. When the high temperature heat is supplied from) to produce steam using this, it is a configuration that can be supplied to the steam supply pipe (16a). The water supplied to the gas generating furnace 10 through the water supply pipe 15b serves to maintain a constant level of the material jacket (not shown) provided on the outer wall of the gas generating furnace 10, and the steam supply pipe 16a. The water vapor supplied through the gas is transported in the gas generator 10 and reacts with the carbon of the coal to generate a combustible gas. At this time, when reducing the steam supplied through the steam supply pipe (16a) it is also possible to discharge the steam to the outside through the discharge pipe (16b).

The blower 16 is configured to supply air into the gas generator 10 through the steam supply pipe 16a, and mix water vapor supplied from the steam tank 15 with air to supply the gas generator 10 into the gas generator 10. Can be. The gas discharge pipe 18 is provided at the upper portion of the gas generating passage 10 and is configured to discharge the non-combustible coal gas generated at the initial stage of operation in the gas generating passage 10 to the outside.

The cyclone 20 connected to the gas discharge pipe 18 is configured to remove dust from coal gas, and the valves 32 and 34 are configured to adjust a supply path of coal gas from which dust is removed. The valves 32 and 34 are water valves that open and close the valves 32 and 34 to control the movement of coal gas by regulating the level of water inside the two valves 32 and 34. A pipe 22 connected from the cyclone 20 is branched from the branch pipe 24 to the primary valve 32 and the secondary valve 34, respectively, and the pipe 32a coming out of the primary valve 32 is Externally, the pipe 34a coming out of the secondary valve 34 is connected to the burner 40 or to the boilers 42 and 44. The gas generated at the beginning of operation of the gas generating furnace is a non-combustible gas and when the non-combustible coal gas discharged from the cyclone 20 is discharged to the outside, the level of the primary valve 32 is lowered, and the level of the secondary valve 34 is lowered. Raises. And when supplying flammable coal gas to the burner 40, the water level of the primary valve 32 is raised and the water level of the secondary valve 34 is lowered. That is, the primary valve 32 and the secondary valve 34 serve as a valve by being adjusted so that the water level is opposite to each other.

The coal gas discharged from the secondary valve 34 may be accelerated by the blower 42 and supplied to the burner 40 or the boilers 42 and 44. Boilers 42 and 44 may include steam hot water boiler 42 and hot water boiler 44. Steam hot water boiler 42 is a structure for heating the hot water by heat exchange after heating the air with a burner, hot water boiler 44 is a structure for heating the water directly with the burner.

When using the gas generating apparatus using the green coal according to the present invention having such a structure, it is possible to implement the above-described gas generating method using the green coal more efficiently.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention as defined by the appended claims. Of the present invention.

Claims

Drying the mined raw coal (non-coking coal: moisture 15 wt% or less, anhydrous reference calorific value 6000 Kcal or more, volatile matter 35-40 wt%, ash 10 wt% or less, sulfur content 0.5 wt% or less);
Manufacturing green coal through a pyrolysis process by heating the raw coal at 500 to 800 ° C. under an air blocking sealed condition; And
Incomplete combustion of the green coal to produce a combustible gas
Gas generation method using the green coal, characterized in that it comprises a.

The method according to claim 1,
The green coal is a gas generating method using the green coal, characterized in that having a particle size of 20mm or less.

The method according to claim 2,
The green coal gas generation method using the green coal, characterized in that having a particle size of 5.6mm or more.

The method according to claim 1,
The green coal has a calorific value of 6000 Kcal / kg or more, and is manufactured using bituminous coal (non-coking coal) containing 15 wt% or less of moisture, 35-40 wt% of volatile matter, 10 wt% or less of ash, and 0.5 wt% or less of sulfur. Gas generation method using the green coal, characterized in that.

The method according to claim 1,
The combustible gas gas generation method using green coal, characterized in that containing CO, H ₂ .

The method according to claim 1,
Gas generation method using the green coal, characterized in that it further comprises the step of purifying the flammable gas.

The method of claim 6,
The purification step,
Gas generation method using green coal, characterized in that to remove harmful gases CO ₂ , SOx, NOx from flammable gas.

The method according to claim 1,
Preparing the combustible gas,
Preparing steam using the high heat of the gas generator; And
Charging the water vapor and air into the gas generating furnace
Gas generation method using the green coal, characterized in that it comprises a.

Hollow gas generating furnace;
A great provided on the inner bottom surface of the gas generating furnace and including an air inlet;
An ash tray provided under the gas generating furnace to discharge ash to the outside;
A hopper provided at an upper portion of the gas generating furnace to supply fuel;
A steam tank provided at one side of the gas generating furnace and supplying steam to the gas generating furnace; And
It is provided on the upper part of the gas generating furnace, the gas discharge pipe for discharging coal gas to the outside
Gas generator using green coal, characterized in that it comprises a.

The method according to claim 9,
The hopper is a gas generator using green coal, characterized in that it comprises an upper hopper and a lower hopper.

The method according to claim 9,
A water supply pipe connected to the gas generating passage from the steam tank and supplying water to the gas generating passage;
A steam discharge pipe is connected to the steam tank from the gas generator, and supplies the heat of the gas generator to the steam tank
Gas generator using green coal, characterized in that it further comprises.

The method according to claim 9,
The gas generating device using the green coal, characterized in that it further comprises a cyclone provided in connection with the gas discharge pipe, the dust contained in the coal gas.

The method of claim 12,
It is provided connected to the cyclone, the gas generating device using the green coal, characterized in that it further comprises a valve for controlling the movement of coal gas.

The method according to claim 13,
The valve is a gas generating device using green coal, characterized in that the water valve comprises a primary valve and a secondary valve.

The method according to claim 14,
The gas generating device using the green coal, characterized in that the water level of the primary valve and the secondary valve is adjusted to be opposite to each other.

The method according to claim 13,
Connected to the valve, the gas generating device using the green coal, characterized in that it further comprises a burner for burning coal gas.

The method according to claim 13,
The gas generator using the green coal is connected to the valve, further comprising a boiler for heating the hot water by burning coal gas.

18. The method of claim 17,
The boiler is a gas generator using green coal, characterized in that it comprises a steam hot water boiler and hot water boiler.