JPH06136371A - Entrained bed coal gasification oven - Google Patents

Abstract

PURPOSE:To prevent the deposition of slag on a water-cooled wall of a gasification room of the title oven without detriment to the gasification capacity of the oven. CONSTITUTION:The entrained bed coal gasification oven is used for subjecting coal to partial combustion in order to convert ash in the coal into a molten slag 13 and produce a gaseous product 14 mainly comprising CO, H2, and CH4. In the oven, a cold-water-cooled wall 6 which is cooled with low-temp. water and constitutes a part of the surrounding water-cooled wall of a gasification room 1 is installed at least in a region where ash becomes a semimolten state having a strong adhesive power. Thus, ash particles in a semimolten state are repelled by and prevented from being deposited on the wall 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spouted bed coal gasification furnace in which slag that adheres and grows on the peripheral wall of a gasification reaction section is suppressed.

[0002]

2. Description of the Related Art In a spouted bed coal gasification furnace, from the viewpoint of discharging ash in coal as molten slag, 1300 to 20
There is a high temperature gas temperature zone of 00 ° C., and the slag in this portion is liquid, and the thickness of adhesion to the wall is as thin as several mm to several tens mm.
On the other hand, since a convection heat exchanger is installed in the downstream of the gasifier outlet, the ash particles at the gasifier outlet must be completely solidified, and the gasifier outlet has a temperature of 800 to 1100 ° C. Must be in the low temperature gas zone.

Therefore, in a spouted bed coal gasifier,
An intermediate temperature gas zone always exists between the high temperature gas zone and the low temperature gas zone, and the ash particles in the intermediate temperature gas zone are in a transition process from a liquid state to a solid state and are in a semi-molten state having a strong adhesive force. The slag that adheres to the wall surface in this intermediate temperature gas zone grows without limitation in thickness as long as the adhesion force to the wall surface and the creep strength of the slag can withstand, and in small furnaces it grows until the gasification furnace is closed. There is. Moreover, the slag generated in this intermediate temperature gas zone is generally so strong that it cannot be removed by wall blowers or other mechanical methods.

In order to solve the above problems, the following method has hitherto been taken.

FIG. 3 shows an example thereof. This spouted bed coal gasification furnace mixes a large amount of low-temperature gas such as recycle gas as quench gas into the outlet pipe of the gasification reaction section while maintaining the gasification reaction section at a temperature above the temperature at which ash melts, and gasifies it. The temperature of the gas and ash particles is rapidly cooled to prevent the adhesion of slag (gas quench).

That is, the outlet pipe 05 of the gasification furnace connected to the gasification reaction section 01 having the burner 02 for charging the coal and the oxygen-containing gas as the gasifying agent and the steam contained in the pressure vessel 04 is provided. A large amount of the low temperature quench gas 03 is mixed in the outlet pipe 05 to rapidly cool the temperatures of the gasified gas and the ash particles to prevent the slag from adhering. In addition, 06 is a gas furnace water cooling wall which forms the gasification reaction part 01, and the circulating water of 300-360 degreeC is circulated.

FIG. 4 shows another example of the conventional technique by water quench. In this spouted bed coal gasification furnace 4, the pressure vessel 016 accommodates a first-stage gasification reaction section 011 and a second-stage gasification reaction section 012 connected to the first-stage gasification reaction section 011. Coal and an oxygen-containing gas as a gasifying agent and steam are charged into the gasification reaction section 011 through a burner 013, and water or water / coal slurry 014 is charged near the inlet of the second-stage gasification reaction section 012. ing. The water or water / coal slurry 014 rapidly cools the gasification gas and ash particles at the outlet of the first-stage gasification reaction section 011 and suppresses the adhesion of slag. Reference numeral 015 is an outlet pipe of the gasification furnace.

FIG. 5 shows a still another example of the prior art, which is a radiant cooler. In the pressure vessel 024, the gasification reaction section 021 and the radiation type water cooling wall 023 as a radiation type cooler connected below the gasification reaction section 021 are housed, and the gasification reaction section 0
21, coal, an oxygen-containing gas as a gasifying agent, and steam are charged from a burner 022, and the radial water cooling wall 02
No. 3 is equipped with a seal gas nozzle 026 while circulating water having a temperature of 300 to 360 ° C. Note that 025
Is an outlet pipe of a gasification furnace connected to an outlet at the bottom of the radial water cooling wall 023. In this jet bed coal gasification furnace, the gasification gas and ash particles at the outlet of the gasification reaction unit 021 are cooled by the radial water cooling wall 023 which is kept clean by a seal gas or the like,
Slag adhesion is suppressed.

[0009]

According to the conventional technique shown in FIG. 3, the gasification reaction section outlet temperature must be kept above the melting point of ash even if the melting point of ash is high. It is necessary to use a flux such as limestone to lower the melting point. Further, a large amount of low-temperature quench gas is required, which is 0.5 to 4 times as much as the weight ratio of the gasification gas, which leads to an increase in power cost and an increase in downstream equipment capacity.

In the conventional technique shown in FIG. 4, the sensible heat of the gasification reaction section outlet gas of the first stage, which should be effectively recovered by the gasification endothermic reaction, is water or water, or the water content in the coal slurry. Because it is consumed by, the unburned char increases,
Coal species compatibility is restricted.

In the conventional technique shown in FIG. 5, since the radiation type water cooling wall is a normal circulating water wall (300 to 360 ° C.), the surface temperature is high and the cleanliness of the radiation type water cooling wall cannot be maintained. It is not possible to lower the outlet temperature, and it is necessary to attach a large number of nozzles for introducing the seal gas in order to maintain the cleanliness.

The present invention intends to provide a jet bed coal gasification furnace which can solve the above problems.

[0013]

Means for Solving the Problems The present invention introduces coal and a gasifying agent consisting of an oxygen-containing gas and steam, partially burns the coal, and discharges ash in the coal as molten slag,
Moreover, in a jet bed coal gasification furnace that generates a gas containing CO, H ₂ and CH ₄ as main components, the same gasification is performed in the gasification reaction section where at least ash is in a semi-molten state where adhesion is strong. It is characterized in that a water cooling wall for cooling the cooling water, which constitutes the peripheral wall of the reaction section, is provided.

[0014]

According to the present invention, in the gasification reaction section, at least in the region of the intermediate temperature where ash is in a semi-molten state where the ash content is strong, a water cooling wall for forming the peripheral wall of the gasification reaction section is provided by cooling water of low temperature. Therefore, the water cooling wall is sufficiently cooled, and the ash particles in the semi-molten state are repelled and the adhesive force is weakened, so that the adhesion of the ash slag can be suppressed.

On the other hand, as described above, since the adhesion of the semi-molten ash particles to the water cooling wall is suppressed and the wall surface is clean, the heat radiation loss from the gas in the gasification reaction section to the wall surface of the water cooling wall is large. However, although there is a concern that the gasification performance will deteriorate, according to the tests conducted by the present inventors, the concentration of particles is high in the spouted bed coal gasification furnace, especially in the spouted bed gasification furnace under pressure. In this state, even if the wall temperature of the water-cooled wall is low and clean, only the gas near the wall loses sensible heat due to radiative heat transfer, and the high temperature gas temperature at the center of the gasification reaction section can be confined as it is. It turned out to be a property. Therefore, in the present invention, the adherent growth of slag can be suppressed without impairing the gasification performance.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIG. The present embodiment relates to a pressurized spouted bed coal gasification furnace used in integrated coal gasification combined cycle power generation facility, and pressure vessel 1
The gasification reaction section 1 is housed in the inside 2, and an outlet pipe 11 for discharging the generated gas 14 above the pressure vessel 12 is connected to the upper part of the gasification reaction section 1. Reference numeral 2 denotes a burner provided below the gasification reaction section 1 for introducing coal, an oxygen-containing gas as a gasifying agent, and steam into the gasification reaction section 1.

The peripheral wall of the gasification reaction section 1 is made of iron and is made up and down.
It is composed of individual water cooling walls 3 and a low temperature water cooling wall 6 made of iron in the middle. The low temperature water cooling wall 6 has an intermediate temperature at which the gas temperature in the gasification reaction section 1 becomes a semi-molten state of ash resulting from combustion. Located in the area. The water cooling wall 3 has a high-pressure steam system (boiler can water) of the coal gas combined cycle power generation system from the viewpoint of efficiency improvement.
High-temperature circulating water having a relatively high temperature (300 to 360 ° C.) is supplied from the inlet line 4, and the circulating water is discharged from the outlet line 5.

A normal temperature water line 8 having a temperature control valve 8a and a normal temperature water of 30 to 150 ° C. and a temperature control valve 9a 2
The hot water line 9 through which hot water of 50 to 360 ° C. merges to form an inlet line 7, water having a lower temperature is supplied from the inlet line 7 to the low temperature water cooling wall 6, and water passing through the low temperature water cooling wall 6 exits the outlet line 10. It is being discharged more.

A thermometer 15 and a flow meter 17 are provided in the inlet line 7, and a thermometer 16 is provided in the outlet line.
Is provided. The signals from the thermometers 15 and 16 and the flowmeter 17 cause the temperature control valve 8a of the hot water line 9 to
9a is controlled. In addition, 13 in FIG.
Is a slag.

In this embodiment, the coal charged from the nozzle 2 partially burns in the gasification reaction section 1 in the presence of an oxygen-containing gas as a gasifying agent and steam, and CO, H ₂ and CH ₄ are added.
The generated gas 14 containing as a main component is generated and discharged from the outlet pipe 11, and the ash content in the coal is discharged outside the furnace as slag 13. The gas is 130 below the gasification reaction section 1.
It has a temperature of 0 to 2000 ° C., is cooled by the water cooling wall 3 and the low temperature water cooling wall 6, and has a low temperature of 800 ° to 1100 ° C. at which the ash particles solidify at the inlet of the outlet pipe 11 and the ash solidifies. It is sent to a convection heat exchanger (not shown).

The low-temperature water-cooling wall 6 is provided in the region of the intermediate temperature of the gas having a strong adhesive force due to the transition of the ash particles from the liquid state to the solid state.
Are arranged.

On the low temperature water cooling wall 6, normal temperature water having a temperature of 30 to 150 ° C. supplied from the normal temperature water line 8 and hot water of 250 to 360 ° C. supplied from a hot water line 9 are temperature control valves 8a and 9a. Water is supplied as cooling water at a temperature adjusted according to the type of coal, operating conditions, etc., and the temperature of the water exiting the outlet line 10 is kept below the saturated water temperature. Temperature control valves 8a, 9
The flow rate of the inlet line 7 is controlled by a.

As described above, since the low-temperature water cooling wall 6 cooled by the low-temperature cooling water having the adjusted temperature is provided in the region of the intermediate temperature of the gas, the ash particles in the semi-molten state have a low temperature. It is repelled by the water cooling wall 6 and the adhesion is weakened, so that the adhesion of slag can be suppressed.

As described above, the low-temperature water cooling wall 6 is kept relatively clean by suppressing the adhesion of slag, but the concentration of ash particles in the gasification reaction section 1 under pressure is high in proportion to the pressure. The sensible heat of the produced gas 14 and the like is lost only by radiative heat transfer in the vicinity of the low-temperature water cooling wall 6, and the high-temperature gas temperature in the center of the gasification reaction section 1 is confined as it is. It is possible to reduce heat dissipation loss and prevent deterioration of gasification performance.

Further, as described above, the temperature and flow rate of the water supplied from the inlet line 8 to the low temperature water cooling wall 6 are controlled depending on the type of coal, operating conditions, etc.
Can detect the temperature of the water in the inlet line 8 and the temperature in the outlet line 9, respectively, and can detect the decrease in the amount of heat absorbed by the low-temperature water cooling wall 6 due to the slag adhering to some extent. When such a decrease in the amount of heat absorbed by the low-temperature water cooling wall 6 occurs, the temperature of the water in the inlet line 8, that is, the low temperature, is controlled by controlling the temperature control valves 8a and 9a by the signals of the thermometers 15 and 16. Adhesive slag can be removed by changing the temperature of the cooling water of the water cooling wall 6 and applying expansion and contraction and temperature change shock to the wall surface of the low temperature water cooling wall 6.

A second embodiment of the present invention will be described with reference to FIG. This embodiment is the same as the first embodiment except that the water cooling wall 3 made of iron constitutes one peripheral wall of the gasification reaction section 1, and the ash in the vertical direction of the water cooling wall 3 has a strong adhesive force. A low temperature water cooling wall 6 made of iron is provided so as to be inscribed in the water cooling wall in the molten region, and the other configurations are the same as those of the first embodiment.

In this embodiment as well, the same operation and effect as those of the first embodiment can be obtained.
Since the low-temperature water cooling wall 6 is provided inscribed in the individual water-cooling wall 3, the range in which the low-temperature water cooling wall 6 is installed can be easily changed, and there is an effect that modification can be easily performed.

In the first and second embodiments, the low-temperature water cooling wall 6 is provided in the region in the middle of the gasification reaction section 1 in the vertical direction in which the ash content is in a semi-molten state with strong adhesion. It is also possible to install this on the entire surface of the gasification reaction section.

[0029]

INDUSTRIAL APPLICABILITY The present invention provides a low temperature cooling water forming a peripheral wall of a gasification reaction section in a region of a gasification reaction section of a spouted bed coal gasification furnace where at least ash is in a semi-molten state with strong adhesion. Since the water cooling wall is provided by the slag, the particles of ash in a semi-molten state are repelled and the adhesion force to the wall surface of the water cooling wall is weakened, and the adhesion of slag can be suppressed, and at the same time, to the cold water cooling wall. Radiative heat transfer is performed only with the gas near the water cooling wall, and the temperature of the gas at the center of the gasification reaction section does not decrease,
It does not impair the gasification performance.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a first embodiment of the present invention.

FIG. 2 is an explanatory diagram of a second embodiment of the present invention.

FIG. 3 is an explanatory view of an example of a conventional spouted bed coal gasification furnace.

FIG. 4 is an explanatory view of another example of a conventional spouted bed coal gasification furnace.

FIG. 5 is an explanatory diagram of still another example of the conventional spouted bed coal gasification furnace.

[Explanation of symbols]

 1 Gasification Reaction Section 2 Burner 3 Water Cooling Wall 4 Water Cooling Wall Inlet Line 5 Water Cooling Wall Outlet Line 6 Low Temperature Water Cooling Wall 7 Low Temperature Water Cooling Wall Inlet Line 8 Room Temperature Water Line 8a Temperature Control Valve 9 Hot Water Line 9a Temperature Control Valve 10 Low Temperature Outlet line of water cooling wall 11 Outlet pipe 12 Pressure vessel 13 Slag 14 Product gas 15, 16 Thermometer 17 Flowmeter

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuhiro Ota 1-1, Atsunoura-machi, Nagasaki-shi Nagasaki Shipyard Ltd. (72) Inventor Tomonori Koyama 5-717-1, Fukahori-cho, Nagasaki-shi Mitsubishi Heavy Industries Nagasaki Institute Co., Ltd.

Claims (1)

[Claims] 1. Coal and oxygen-containing gas and steam
Injecting a gasifying agent to partially burn coal to remove ash in the coal
Is discharged as molten slag, and CO, H ₂And CH
_FourBed Coal Gasification Furnace to Generate Gas Containing Carbon as Main Component
In the gasification reaction section, at least ash has strong adhesiveness
The peripheral wall of the gasification reaction section is configured in the semi-molten region
It is characterized by the provision of a water cooling wall with low temperature cooling water
Spout bed coal gasifier.