JPH08143875A - Prevention of ash from sticking to wall of gasifying furnace - Google Patents

Abstract

PURPOSE: To enable the continuous operation for a long period and obtain a produced gas at a low cost by gasifying a petroleum coke containing a prescribed amount of an inorganic mineral at a higher temperature than the ash melt flowing point of the inorganic mineral in a gasifier and efficiently preventing the ash from sticking to a wall of the gasifying furnace. CONSTITUTION: An inorganic mineral 21 containing a large amount of active components, e.g. K2 O, MgO, Al2 O3 , CaO, Na2 O and SiO2 such as coal ash in an amount of >=3 pts.wt. based on 1 pt.wt. ash in a petroleum coke 20 is mixed therewith in gasifying the petroleum cake 20 in a gasifying furnace 6 by partial oxidizing reaction so as to heighten the gasifying operation temperature from the ash melt flow point and carry out the gasification. Thereby, the ash is prevented from sticking to a wall of the gasifying furnace.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of preventing ash from adhering to a gasification furnace wall when petroleum coke is mixed with an inorganic mineral for gasification.

[0002]

2. Description of the Related Art A method has been tried in which coal is mixed with petroleum coke, slurried, and gasified by partial oxidation reaction with oxygen. At the time of this gasification, the gasification operating temperature is set higher than the coal melting temperature of ash, Gasification was carried out to prevent the ash content from adhering to the gasification furnace wall.

[0003]

However, in such a method of mixing coal with petroleum coke, it is difficult to apply it only to an area where coal is available, and the available area is likely to be limited to some extent. In the method of mixing coal and gasifying petroleum coke,
If a large amount of coal is used, the unit price of the generated gas will be high and it will be difficult to make a profit. Such problems were pointed out.

On the other hand, although a method of gasifying with only petroleum coke can be considered, however, since the melting point of petroleum coke ash is usually 1500 ° C. or higher in a reducing atmosphere, the ash content of petroleum coke remains on the gasification furnace wall. Adhered and deposited,
There was a disadvantage that I could not drive for a long time.

The present invention has been made in view of the above problems, and recycles inorganic minerals, such as fly ash, bottom ash, blast furnace slag, and converter slag, which are no longer needed at coal-fired power plants, steel plants, etc., as flux. The purpose is to prevent the adhesion of ash to the gasification furnace wall by mixing the mineral minerals with petroleum coke.

[0006]

In order to achieve the above object, in the present invention, when petroleum coke is gasified by a partial oxidation reaction in a gasifier, 1 part by weight of ash in the petroleum coke is used. The inorganic mineral was mixed at a ratio of 3 or more parts by weight, and the gasification operation temperature was set higher than the ash flow point of the inorganic mineral for gasification.

[0007]

[Function] A petroleum coke and an inorganic mineral are mixed, and in the gasification device, the ash portion melt temperature of the inorganic mineral is 1150 to 1
By gasifying at a gasification temperature of 1250 to 1450 ° C. higher than 350 ° C., the ash content of the inorganic minerals melts down the wall of the gasification furnace, so the ash content of petroleum coke is also captured by the ash content of the inorganic minerals. Flow down together,
These ash components are cooled and solidified in the quenching chamber and taken out from the gasifier as slag. In this way, it is possible to prevent the ashes of petroleum coke from adhering to the gasification furnace wall.

[0008]

EXAMPLE An example of a method for preventing ash from adhering to the wall of a gasification furnace according to the present invention will be described below with reference to FIG.

FIG. 1 is a system diagram of an apparatus suitable for carrying out the method of the present invention. The flow of a so-called Texaco method in which a solid fuel and an inorganic mineral are wet pulverized to form a slurry, which is partially oxidized by oxygen and gasified, FIG. 2 is a relation between the mixing ratio of the inorganic minerals to the ash content in the petroleum coke and the ash adhesion rate, and FIG. 3 is a system diagram of a suitable apparatus for pre-pulverizing the converter slag.

In FIG. 1, petroleum coke (melting point of ash of this coke is about 1600 ° C.) 20 and inorganic mineral (melting point of ash of this inorganic mineral is about 13).
21 at 50 ° C. with appropriate amount of water
It is charged into the slurry tank 3 and wet pulverized, and is supplied to the slurry tank 3 as a slurry of petroleum coke 20-inorganic mineral 21-water through a line 22.

The slurry tank 3 is equipped with a stirrer 3a, and the petroleum coke 20-inorganic mineral 21-water slurry supplied from the pulverizer 1 is temporarily stored in the slurry tank 3.

Next, petroleum coke 20-inorganic mineral 21-
The slurry of water is supplied to the line 12 by the slurry supply pump 4.
Is sent to the burner 5, is supplied to the gasification furnace 6 together with 40 to 60% of the theoretical combustion oxygen amount of petroleum coke, and is gasified (partial oxidation) at a temperature of 1250 to 1450 ° C. The pressure in this gasification furnace is preferably about 20 to 80 atm (2.0 × 10 ^{6 to} 8.1 × 10 ⁶ Pa).

The upper part of the gasification furnace 6 is lined with a refractory 7a to form a reaction chamber 7. The lower part of the gasification furnace 6 is provided with a quenching chamber 8, and the reaction chamber 7 and the quenching chamber 8 are connected by a throat section 9. Water is sent from the line 13 to the quenching chamber 8 for gas quenching so that the water can be stretched to an appropriate height, and a cylindrical dip tube 10 and a draft tube so that the lower end is submerged in this water. 11 is provided coaxially.

The gas generated in the reaction chamber 7 passes through the throat portion 9 and the dip tube 10 and is blown into the water in the quenching chamber 8. After that, the gas is discharged from the gas outlet 14a provided in the region above the water surface of the quenching chamber 8 to the line 1
4 and is sent to a device (not shown) on the downstream side.

When gas is blown into the water in the quenching chamber 8, the ash and unburned carbon produced when the petroleum coke 20 containing the inorganic mineral 21 is gasified is mixed with water and rapidly cooled, Fine slag, which is relatively fine particles, is collected in water and a slurry containing these is generated. This slurry is taken out from a line 15 connected to the side wall of the quenching chamber 8. From the line 16 at the bottom of the quenching chamber 8, a slurry called coarse slag containing relatively coarse particles is taken out.

The prevention of adhesion of ash to the wall of the gasification furnace by gasification of the slurry in which the mineral mineral 21 is mixed with the petroleum coke 20 in the gasifier constructed as described above will be described.

First, Table 1 shows typical elemental analysis values of the petroleum coke 20 used in this example, the ash component and the ash melting point when the ash content of the petroleum coke is 100%.

[0018]

[Table 1]

Next, according to the present invention, the petroleum coke 20
Inorganic minerals 21 mixed with and having a role of preventing adhesion to the gasification furnace wall are fly ash (collected by an electric dust collector, etc.) generated from the boiler of a coal-fired power plant, bottom ash (accumulated at the bottom of the boiler). Slag) and slag such as blast furnace slag and converter slag generated from steelworks, and typical compositions of these inorganic minerals are shown in Table 2.

[0020]

[Table 2]

As described above, the petroleum coke 20 used in this embodiment
The typical elemental analysis values and compositions of the inorganic mineral 21 have been described above. In particular, regarding the inorganic mineral 21, coal ash is representatively described in the present embodiment.

First, the case where only the petroleum coke 20 is gasified will be described. Petroleum coke 20 is 0.1-1.
It contains 5% ash, and vanadium is contained in the ash.

The melting point of vanadium in the reducing atmosphere is 1800 ° C., which is usually higher than the gasification operating temperature of petroleum coke 20 (1250-1450 ° C.). For this reason,
During the gasification of the petroleum coke 20, the ash content is not melted but adheres and is deposited on the surface of the refractory 7a in the reaction chamber 7, and the ash mass grown and accumulated causes the throat portion of the gasification furnace 6 to grow. No. 9 was closed, and long-term continuous operation was difficult.

The following can be considered as the cause of this. That is, the ash content in the petroleum coke 20 is 0.1 to 10 times higher than that of the same gasification raw material coal.
Although it is as small as 1.5%, vanadium in ash is generally large, and a partial oxidation reaction is carried out in a state where oxygen is insufficient.
It is in the state of valent vanadium.

Therefore, the melting point in the reducing atmosphere is 1
As high as 800 ° C., and in the state where the gasification operating temperature of the ordinary petroleum coke 20 is 1250 to 1450 ° C., the ash component adheres to and accumulates on the gasification furnace wall in a highly viscous state and flows down from the gasification furnace wall only by its own weight It is only for this reason, and residual deposits will occur during the flow.

In order to investigate such a cause, in the present embodiment, among the inorganic minerals 21 shown in Table 2, especially SiO2, A
l2 O3, Fe2 O3, Na2 O, CaO, MgO, K
Focusing on coal ash containing a large amount of 2 O active ingredients (here, coal ash refers to fly ash and bottom ash), the ash contained in petroleum coke 20 is assisted by coal ash having a low melt point. It tried to prevent it from flowing down and sticking to the wall of the gasification furnace.

In this case, K2O, MgO, Al2O3, Ca was added to 1 part by weight of ash of petroleum coke 20.
When 3 or more parts by weight of coal ash containing a large amount of active components of O, Na2 O and SiO2 are mixed and blown into the gasification furnace 6 through the burner 5, the oil that would normally be deposited in the gasification furnace 6 Since the ash content of the coke 20 is prevented from being removed by the melt flow of coal ash, the throat portion 9 is not blocked and the long-term continuous operation is possible.

In order to prevent the ash in the petroleum coke 20 from adhering to the wall of the gasification furnace, the data shown in FIG. 2 was obtained. That is, as shown in FIG. 2, the gasification operation temperature was 1400 ° C. and the pressure was 38 kg / cm ² G (3.8 × 1).
( ⁶ Pa) under the ash content (1
It was confirmed that when the proportion of coal ash as an inorganic mineral was increased from 0 with respect to (part by weight), the attachment rate of ash to the gasification furnace wall decreased.

Therefore, based on the data shown in FIG. 2, in the present invention, when the petroleum coke 20 is gasified,
Eliminate the adherence of ash to the gasification furnace wall, or if the adherence occurs, make the adhered amount that allows long-term continuous operation, that is, make the adherence rate of ash to the gasification furnace wall 2% or less. Therefore, the amount of coal ash is set to 3 parts by weight or more for 1 part by weight of ash in the petroleum coke 20.

The reason for this is that among the ash components of coal ash,
Acidic components such as SiO2, Al2 O3, Fe2 O3,
Although there are basic components such as CaO, MgO, Na2 O, and K2 O, the former acidic component has the effect of raising the melting point of the ash of coal ash and the effect of washing the ash, which are contrary to each other.

On the other hand, the latter basic component has the effect of lowering the melting point of the ash of coal ash and the similar effect of washing, but the ash content in the petroleum coke 20 charged into the gasification furnace 6 is 1 weight. When the amount of coal ash as the inorganic mineral 21 is 3 parts by weight or less with respect to the parts, the absolute ratio of the inorganic mineral to the amount of ash in the petroleum coke becomes small, and the above-mentioned acidic component is the melting point of the ash of coal ash. The effect of adversely increasing the melting point of the ash ash of coal ash due to the acidic component is the cleaning effect of the acidic component and the dissolution of ash of coal ash in the basic component The reason is that the effect of lowering the pour point and the effect of exceeding the cleaning effect) occur, and as shown in FIG. 2, the ash content in the petroleum coke 20 increases the deposition rate on the wall of the gasification furnace.

According to the findings obtained in the course of various experiments,
Of the active ingredients in the inorganic mineral 21 shown in Table 2, SiO
When there are many acidic components such as 2 and Al2 O3, the melting point of the inorganic mineral 21 rises, so it was difficult to flow down the ash content in the petroleum coke 20 deposited on the gasification furnace wall.

On the contrary, Fe2 O3, CaO, MgO, Na
When there are a large amount of basic components such as 2 O and K 2 O, the melting point of the inorganic mineral 21 is lowered, and the ash content of the inorganic mineral 21 also includes the ash content of the petroleum coke 20 when it is melted down the gasification furnace wall surface. It is possible to prevent the ash of the petroleum coke 20 from being deposited on the gasification furnace wall by being captured by the ash of the inorganic mineral 21 and flowing down together.

As described above, although the acidic component in the inorganic mineral 21 has the effect of raising the melting point, it has the effect of lowering the melting point of the basic component, and consequently the acidic component and the basic component. The gasification temperature higher than the melt flow temperature of the inorganic mineral 21 containing both is selected, and the ash content of the inorganic mineral 21 causes the melt flow down the wall surface of the gasification furnace under the temperature condition in which the inorganic mineral 21 easily melts.

However, among the inorganic minerals 21, particularly with respect to coal ash, since the properties of the coal used differ depending on the place of origin, the basic components in the coal ash generated from the boiler of the coal-fired power plant also differ. For this reason, when the ratio of the basic component is small, the melting point of the coal ash can be increased by adding 0.7 to 0.9 part by weight of the basic component of CaCO3 to 1 part by weight of the coal ash. It is possible to lower it.

Although the case where the petroleum coke 20 and the coal ash having an ash melting point of 1350 ° C. are mixed and supplied to the gasification furnace 6 has been described above, blast furnace slag and converter slag can also be used.

That is, as shown in FIG. 3, among the blast furnace slags or converter slags, particularly those in the converter slag 30 which have a generally agglomerated particle size are processed by the preliminary crusher 32 of the dry crusher into desired particles. The ash that has been crushed to a diameter is charged with the petroleum coke 20 and an appropriate amount of water in the crushing device 1 in the next step, and the slurry that has been wet crushed is supplied into the gasification furnace 6. It has the same effect as coal ash.

Table 2 shows the ash component values of slag such as blast furnace slag and converter slag. The component value of Fe2 O3 constituting this ash component is 0.3 to 0.8 (% in blast furnace slag). ), This component value is a component value indicating FeO.

The component value of Fe2 O3 in the converter slag is 10 to 27 (%), and this component value indicates the component value of Fe, which is the sum of Fe2 O3 and FeO.

In the present invention, the temperature T0 of the partial oxidation reaction in the reaction chamber 7 is preferably 30 to 100 ° C. higher than the melt flow point T of the ash of the inorganic mineral. That is, the temperature T0 in the reaction chamber 7 is (T + 30) ° C. or higher, and (T + 1)
It is preferably 00) ° C. or lower. In addition, in this embodiment, when the basic component of the inorganic mineral such as coal ash or slag is small, it is described that the basic component of limestone (CaCO3) is newly added, but the present invention is not limited to this and oxidation is performed. The melting point of the inorganic mineral may be lowered by adding iron powder.

[0041]

As is apparent from the above description, according to the present invention, when petroleum coke is gasified by a partial oxidation reaction in a gasifier, an inorganic matter is added to 1 part by weight of ash in the petroleum coke. By mixing minerals in a proportion of 3 or more parts by weight and performing gasification by setting the gasification operating temperature higher than the ash melting point of the inorganic minerals, the ash content contained in the inorganic minerals is melted. During this process, the ash of petroleum coke also flows down, so that good long-term stable continuous operation is possible without sticking to the gasification furnace wall. In addition, since the available inorganic minerals are used, unlike the case of using coal, it is not limited to the supply base, and the unit price of the generated gas is low.

[Brief description of drawings]

FIG. 1 is a systematic diagram of an apparatus suitable for carrying out the method of the present invention.

FIG. 2 is a relationship between a mixing ratio of an inorganic mineral to an ash content in petroleum coke and an ash adhesion rate.

FIG. 3 is a systematic diagram of a preferred device similar to the present invention.

[Explanation of symbols]

 1 Crusher 3 Slurry tank 5 Burner 6 Gasifier 7 Reaction chamber 8 Quenching chamber 9 Throat section 20 Petroleum coke 21 Inorganic minerals

Claims (1)

[Claims] 1. When the petroleum coke is gasified by a partial oxidation reaction in a gasifier, the inorganic mineral is mixed in a proportion of 3 or more parts by weight with respect to 1 part by weight of the ash content in the petroleum coke, and the gas is mixed. A method for preventing adhesion of ash to the wall of a gasification furnace, characterized in that the gasification operation temperature is set to be higher than the ash melting point of the inorganic mineral to perform gasification.