JPH01172494A - Coal gasification equipment - Google Patents

Abstract

PURPOSE:To control the calorific value of generated gas and to prevent ashes in char from melting and sticking, by supplying an oxidizing gas containing O2 into an upper reaction chamber through a supply means for combustion of the combustible gas in gas and part of the carbon in char. CONSTITUTION:Coal and an oxidizing gas containing O2 are supplied through supply lines 5-7 into a lower reaction chamber 1, where C, H2, etc. in the coal and recovered char are reacted for conversion into gas, and ashes are melted and discharged from the system through a molten slag outlet 10. The gas and char generated in the reaction chamber 1 are sent to a middle reaction chamber 2, where the coal and oxidizing gas supplied through supply lines 8 and 9 are burned and reacted for conversion into gas and char. The gas and char from the middle reaction chamber 2 are sent to an upper reaction chamber 3, where they are burned and reacted with an oxidizing gas supplied through a supply line 13 to raise the temperature of the char. The gas generated in the reaction chamber 3 is sent through a line 11 to a recovery unit 4, where it is separated into crude gas and recovered char. The recovered char is sent through a supply line 6 to the reaction chamber 1.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a coal gasification apparatus that gasifies solid fuel such as coal and converts it into gas fuel.

[Conventional technology]

The conventional coal gasifier, which will be explained based on FIG. It consists of Coal is supplied to the lower reaction chamber 1 from a coal supply line 5, recovered char is supplied from a recovered char supply line 6, and oxidizing gas having an oxygen concentration of 20 to 100% is supplied from an acidic gas supply line 7. Coal and an oxidizing gas having an oxygen concentration of 20 to 100% are supplied to the middle reaction chamber 2 from a coal supply line 8 and an oxidizing gas supply line 9, respectively.

In the lower reaction chamber 1, the middle reaction chamber 2, and the upper reaction chamber 3, the following reactions for converting coal into gas pressure occur simultaneously.

When coal is heated from room temperature to a temperature of 400°C or higher, a portion of the coal undergoes thermal decomposition and is converted into hydrogen, carbon oxide, carbon dioxide, water vapor, methane, ethane, ethylene, and trace amounts of high-boiling hydrocarbons. A so-called devolatilization reaction occurs. Coal after the devolatilization reaction becomes a solid called char, which mainly consists of carbon and ash.

The carbon in the char reacts with water vapor or carbon dioxide gas and is converted into hydrogen and carbon monoxide as expressed by the following chemical formulas 1 and 2.

C+H, 0=CO+H! ...First formula C+ Co,
= 2 Co ----- Second Formula The above two reactions proceed from the left side to the right side at a temperature of 850 t: to 2000 t:. In this qmv, the first two reactions will be collectively referred to as the gasification reaction.

These gasification reactions are endothermic reactions, and the inside of the reaction chamber is
In order to maintain the temperature at ``C~2000υ, a gas containing oxygen is supplied into the reaction chamber to cause a reaction between the carbon in the char, the coal, and the combustible gas in the generated gas with oxygen, that is, a combustion reaction. Generates heat of combustion.

In the lower reaction chamber I, carbon, hydrogen, oxygen, etc. in the coal and recovered char are converted into gas by a devolatilization reaction, a gasification reaction, and a combustion reaction. At the same time, the temperature of the lower reaction chamber 1 is adjusted to a temperature higher than the temperature at which the coal and the ash in the recovered char melt, and the ash is melted and discharged as slag to the outside of the system from the molten slag discharge port 10. The gas and char generated in the lower reaction chamber 1 are sent to the middle reaction chamber 2 and are used as a heat source for devolatilizing the coal supplied from the coal supply line 8. In the middle reaction chamber 2, the coal is converted into gas and char by a devolatilization reaction, a gasification reaction, and a combustion reaction using the oxidizing gas supplied from the oxidizing gas supply line 9. The gas and char generated in the middle reaction chamber 2 are transferred to the upper reaction chamber 3.
The gas is cooled by heat absorption from the gasification reaction and heat radiation from the gas to the surrounding walls. The gas generated from the upper reaction chamber 3 is
The generated gas is sent to the char recovery device 4 through the line 11, and the generated gas is separated into crude purified gas and recovered char.The crude purified gas is recovered through the crude gas line 12, and the recovered char is conveyed through the recovered char supply line 6 to the lower reaction chamber 1. sent to.

[Problem that the invention seeks to solve]

FIG. 8 shows the relationship between time and temperature when the char of a certain coal (diameter: 50) becomes zero due to gasification reaction (curve ■) or combustion reaction (curve). It can be seen that when the gasification temperature becomes 1500e or higher, the difference between the gasification reaction rate (curve curve), which is an endothermic reaction, and the combustion reaction rate (curve n), which is an exothermic reaction, rapidly decreases.

In the lower reaction chamber 1, in order to melt the ash in the coal and discharge it out of the system as slag, it is necessary to maintain the temperature in the trap lower reaction chamber 1 above the melting temperature of the ash in one coal. In the case of coal that has a high ash melting temperature and requires the temperature of the lower reaction chamber 1 to be maintained at 1,600 υ or higher, the partial combustion rate of the lower reaction chamber 1 (the partial combustion rate of the lower reaction chamber 1 (supplied to the lower reaction chamber 1) is determined as shown in Figure 9. The amount of oxygen required to convert the carbon and hydrogen of the coal and char supplied to the lower reaction chamber into CO3 and H) must be set to a large value of 0.6 to 0.8. It won't happen. At the ash melting temperature of 1,600 υ or higher, the gasification reaction rate and combustion reaction rate of carbon in the char are about the same, and in order to maintain the temperature at 1,600 υ or higher, K is the hydrogen and carbon monoxide produced in the gasification reaction. It is necessary to burn a part of the fuel, and it is necessary to supply the oxygen necessary for that combustion, resulting in a large partial combustion ratio.

Char that has not been completely gasified in the upper reaction chamber 3 is recovered by a char recovery device 4 and supplied as recovered char to the lower reaction chamber IK, where it is gasified and combusted in the lower reaction chamber 1. In the case of char having a slow gasification reaction rate, a large amount of recovered char is generated to be gasified and burned in the lower reaction chamber 1, so the amount of coal supplied from the coal supply line 5 is reduced to cope with the busy situation. This is being dealt with by increasing the amount of coal supplied from the coal supply line 8. However, in this method, as the amount of recovered char to be treated in the lower reaction chamber 1 increases as shown in FIG. There is also a partial combustion ratio of the entire gasifier (amount of oxygen supplied to the gasifier/carbon and hydrogen of coal supplied to the gasifier).
COl in the generated gas increases.

There were problems in that the ratio of H and O increased, the calorific value of the crudely purified gas decreased, and the temperature of the generated gas in the upper reaction chamber 3 was too high, leading to pipe closure due to adhesion of char.

As mentioned above, 1. When using conventional equipment to gasify coal, which has a high ash melting point and a slow gasification reaction rate, the calorific value of the generated gas decreases and There was a problem in that the ash melted and adhered, clogging the pipes.

The present invention was made in view of the current situation, and it is an object of the present invention to provide a coal gasification device in which the calorific value of the generated gas does not decrease and the pipes are not clogged due to melting and adhesion of ash in the char. .

[Means for solving problems]

The present invention comprises a lower reaction chamber which is equipped with means for supplying coal, recovered char and oxidizing gas, and has a molten slag discharge port at the bottom; A gasifier comprising a middle reaction chamber having a supply means, an upper reaction chamber connected to the upper part of the middle reaction chamber and communicating with the middle reaction chamber and having a means for supplying oxidizing gas, and a pressure connection of the upper reaction chamber. The present invention proposes a coal gasification apparatus characterized in that it is equipped with a char recovery device connected to a recovered char supply means connected to the lower reaction chamber.

[Effect]

In order to increase the gasification reaction rate of char in the coal, an oxidizing gas containing oxygen is supplied to the upper reaction chamber by an oxidizing gas supply means connected to the upper reaction chamber, thereby reducing the combustible gas in the gas in the upper reaction chamber. A part of the carbon in the char is combusted to raise the temperature of the char in the upper reaction chamber. As the temperature of the char increases, the gasification reaction rate of the char increases,
The calorific value of the generated gas increases, the temperature of the generated gas decreases, and melting and adhesion of ash is prevented. Note that if the amount of oxidizing gas supplied is excessive, the temperature of the gas generated at the outlet of the upper reaction chamber will become too high. The proportion of carbon gasified and burned in the reaction chamber is reduced.

To achieve this, the temperature of the char in the upper reaction chamber is set to (1-A) the rate at which the carbon in the char in the upper reaction chamber is gasified and burned.
The temperature is set to be calculated from the char gasification reaction rate as shown in FIG. 8 so as to increase the temperature.

When oxidizing gas is supplied to the upper reaction chamber at 5K, the gasification reaction rate of the char is slow, especially the carbon in the char which has the property that the gasification reaction rate slows down as the carbon concentration in the char decreases. Since the gasification reaction rate can be increased, the proportion of carbon gasified and combusted in the lower reaction chamber out of the carbon supplied to the gasifier can be reduced, suppressing a decrease in the calorific value of the generated gas and melting the char. Can prevent adhesion.

〔Example〕

A coal gasification apparatus according to an embodiment of the present invention will be explained with reference to FIG. In FIG. 1, parts with the same reference numerals as those in FIG. 7 indicate parts having the same functions as the parts shown in FIG. A middle reaction chamber is connected to the upper part of the reaction chamber 1 and communicates with the lower reaction chamber 14; 3 is an upper reaction chamber which is also connected to the upper part of the middle reaction chamber 2 of the gasifier and communicates with the middle reaction chamber 2; 4 is an upper reaction chamber. A char recovery device connected to the reaction chamber 3; 5 a coal supply line connected to the lower reaction chamber; 6 a char recovery device 4;
a recovery char supply line connecting the lower reaction chamber 1 and the lower reaction chamber 1;
is an oxidizing gas supply line connected to the lower reaction chamber IK, 8 is a coal supply line connected to the middle reaction chamber 2, 9 is an oxidizing gas supply line connected to the middle reaction chamber 2, and 10 is the bottom of the lower reaction chamber 1 11 is a line connecting the upper reaction chamber 3 and the char recovery device 4; 12 is a molten slag discharge port opened to
13 is a crude gas line connected to the char recovery device 4, and 13 is an oxidizing gas supply line connected to the upper reaction chamber 3.

In the coal gasifier having such a configuration, the lower reaction chamber IK receives coal from the coal supply line 5 and recovers char from the recovered char supply line 6 at an oxygen concentration of 20 to 100%.
oxidizing gases are supplied from the oxidizing gas supply line 7, respectively. Coal is supplied to the middle reaction chamber 2 from a coal supply line 8 and oxidizing gas having an oxygen concentration of 20 to 100% is supplied from an oxidizing gas supply line 9.

An oxidizing gas having an oxygen concentration of 20 to 100 is supplied to the upper reaction chamber 3 from an oxidizing gas supply line 13. In the lower reaction chamber 1, carbon, hydrogen, etc. in the coal and recovered char are converted into gas by devolatilization reaction, gasification reaction, and combustion reaction pressure, and at the same time, the temperature at which the coal, recovered char, and ash in it melts is maintained. The temperature of the lower reaction chamber 1 is maintained as above, and the ash is melted and discharged as molten slag to the outside of the system from the molten slag discharge port 10. The gas and char generated in the lower reaction chamber 1 are sent to the middle reaction chamber 2 and are used as a heat source for devolatilizing the coal supplied from the coal supply line 8.Middle reaction chamber 2
In the process, coal is converted into gas and char by a devolatilization reaction, a gasification reaction, and a combustion reaction using the oxidizing gas from the oxidizing gas supply line 9. The gas and char generated in the middle reaction chamber 2 are sent to the upper reaction chamber 1, where they undergo a combustion reaction with oxygen in the oxidizing gas supplied from the oxidizing gas supply line 13 and having an oxygen concentration of 20 to 100%, thereby increasing the char temperature. increases, promoting the gasification reaction. Depending on the type of coal, if the gasification reaction is slow, an oxidizing gas having an oxygen concentration of 20 to 100% is further supplied to raise the char temperature and promote the gasification reaction.

In this way, the amount of recovered char decreases, the calorific value of the generated gas increases, and the temperature of the generated gas is lowered to prevent the char from melting. The generated gas from the stage reaction chamber 3 is sent to the char recovery device 4 through the line 11, where the generated gas is separated into crude purified gas and recovered char, and the recovered char is sent to the lower reaction chamber 1 through the recovered char supply 2-in-6. Sent.

FIG. 2 is a detailed side sectional view of a gasifier consisting of a lower reaction chamber 1, a middle reaction chamber 2, and an upper reaction chamber 3. In FIG. 2, the inside of the gasifier consists of a lower reaction chamber 1, a middle reaction chamber 2, and an upper reaction chamber 3, and is surrounded by an outer wall 15. The outer wall 15 is lined with a fireproof heat insulating material 16 in a portion where the gasification reaction occurs. A cooling pipe 17 is installed in the upper part of the upper reaction chamber 3 to cool the generated gas. Cooling pipe 1
Cooling water is supplied to 7, and after heat recovery, it is discharged outside the system. FIG. 3 is a cross-sectional view taken along line I-1 in FIG. 2, showing the coal supply nozzle 18 for transporting coal with an oxidizing gas and sending it into the lower reaction chamber IK, and the coal supply nozzle 18 for transporting the recovered char in an airflow using an oxidizing gas. Char supply nozzle 19 for feeding the char into the lower reaction chamber 1
and an oxidizing gas supply nozzle 20 are opened in the outer wall 15 of the lower reaction chamber 1 in a direction offset from the center line.

FIG. 4 is a sectional view taken along the line IV-IV in FIG. 2, and shows a coal supply nozzle 21 attached to the outer wall 15 for transporting coal with an oxidizing gas and sending it into the middle reaction chamber 2. FIG. 5 is a sectional view taken along V-VHK in FIG. 2, and an oxidizing gas supply nozzle 22 for supplying oxidizing gas to the upper reaction chamber 3 is attached to the outer wall 15. FIG. 6 is a sectional view taken along line VI-VI in FIG. 2. 17 in Figure 6
is a cooling pipe and is installed around the inside of the fireproof heat insulating material 16 in the upper part of the upper reaction chamber 1.

According to the coal gasifier trap of this embodiment, it is possible to prevent a decrease in the calorific value of the generated gas and to prevent clogging of the pipe line due to melting and adhesion of char particles.

〔Effect of the invention〕

The problem with the coal gasifier of the present invention is that the reaction rate of the gasification reaction in the upper stage reaction chamber is slow, resulting in a decrease in the calorific value of the generated gas and the ash in the char melting and adhering to the pipes, clogging the pipes. It has the unique effect of being able to solve problems.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a coal gasification apparatus according to one embodiment of the present invention,
Figure 2 is a side cross-sectional view of the gasifier according to the upper h-pi embodiment, Figure WJ3 is a cross-sectional view taken along line I-1 in Figure 2, and Figure 4 is a cross-sectional view taken along line I-1 in Figure 2.
5 is a sectional view taken along the line V-IV in FIG. 2, FIG. 6 is a sectional view taken along the line ■-■ in FIG. 2,
Figure 7 is an explanatory diagram of a conventional coal gasifier, and Figure 8 is a diagram of a conventional coal gasifier.
Figure 9 is a graph showing the relationship between the partial combustion rate and temperature in the lower reaction chamber, and Figure 10 is a graph showing the temperature dependence of the gasification reaction and combustion reaction of the char of
It is a graph showing the relationship between the proportion of carbon to be combusted and the partial combustion proportion of the entire gasifier. 1--lower reaction chamber, 2--middle reaction chamber, 3-upper reaction chamber, 4--char recovery device, 5, 8...coal supply line, 6--recovered char supply line, ? , 9°13-
・Oxidizing gas supply line, lO-・Molten slag discharge port, 1
1... Line, 12... Crude gas line, 17-...
Cooling pipe, 18.21--Coal supply nozzle, 19--Char supply nozzle, 20.22--Oxidizing gas supply nozzle. Representative Patent Attorney Akira Sakama 2 people Figure 2 Figure 3 Shunda ↓ Shigasu Figure 4Z Figure 5 Oxidation ↑ Oxidation Figure 7 Figure B 1300 1000 1200 /400
1600 1BOO) Meng Xia [0C] qth thought 0.4 0.6 0.8 1.0 Lower stage transmission dragon for the charcoal millet that is relaxed and supplied 41. Force partial firing ratio 10th section OA O, 57,0

Claims (1)

[Claims] A lower reaction chamber is provided with means for supplying coal, recovered char and oxidizing gas, and has a molten slag discharge port at the bottom; and a lower reaction chamber is connected to the upper part of the lower reaction chamber and communicates with the lower reaction chamber, and has means for supplying coal and oxidizing gas. a gasifier comprising: a middle reaction chamber having a gasifier; A coal gasification apparatus comprising: a char recovery device connected to a recovered char supply means connected to the lower reaction chamber.