JPH10121066A - Production of petroleum coke slurry - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the settlement of a high-specific-gravity iron concentrate used as a melting point lowering agent for fly ash. SOLUTION: When petroleum coke 20 is gasified by partial oxidation in a gasifier, 3-20 pts.wt. inorganic mineral 21 is added to 1 pt.wt. ash in the coke 20. The inorganic mineral comprises fly ash and a melting point lowering agent therefor comprising CaO and an iron concentrate. Especially, the iron concentrate has a high specific gravity and is settled. However, when swollen and gel-like bentonite prepared by previously adding water to bentonite is added to an iron concentrate, and the entire mixture is mixed under agitation, a lowly viscous iron concentrate slurry not undergoing the settlement of the concentrate can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a petroleum coke slurry having excellent storage stability. More specifically, in the present invention, the ash component generated when the finely divided solid fuel of petroleum coke-water slurry is subjected to a partial oxidation reaction in the Texaco gasification furnace adheres and accumulates on the gasification furnace wall without melting. Iron concentrate and CaO are added as a low melting point fly ash and a melting point depressant of the fly ash, but particularly when producing a high specific gravity iron concentrate slurry, bentonite is added to the water content of the iron concentrate slurry. 2-8
The present invention relates to a method for producing a petroleum coke slurry having excellent storage stability by preventing the sedimentation and separation of iron concentrate by adding it by weight.

[0002]

2. Description of the Related Art In recent years, petroleum coke has been reviewed as an energy source. In particular, in order to convert petroleum coke into a fluid fuel such as petroleum, so-called petroleum coke slurry, the development of a fluid fuel which converts petroleum coke into fine powder and disperses water into petroleum coke slurry has been promoted.

[0003]

When such petroleum coke slurry is gasified, 0.1-0.1%
It contains 1.5% of ash, and further contains vanadium in the ash.

However, the ash content of petroleum coke has an ash content of 0.1 to 0.1 times that of coal of the same gasification raw material.
Although it is as small as 1.5%, vanadium in ash is generally large, and a partial oxidation reaction is performed in a state where oxygen is insufficient.
It is in a valence or tetravalent vanadium oxide state.

[0005] The melting point temperature of this vanadium in a reducing atmosphere is as high as 1800 ° C, and the ash component adheres to the gasification furnace wall in a state of high viscosity at the usual gasification operation temperature of petroleum coke of 1250 to 1450 ° C. -There is a problem that the material only accumulates and flows down from the gasification furnace wall only by its own weight, and adheres and accumulates on the gasification furnace wall in the middle of the flow and cannot be operated for a long time.

In order to solve this problem, coal ash generated from a boiler of a coal-fired power plant is used as a flux of ash of petroleum coke, for example. When the melting point is high, new CaCO ₃ or Fe ₂ O ₃ is mixed and added to lower the melting point of the coal ash, and the melting point (F.
T. ) And gasification of petroleum coke,
The ash content of petroleum coke is also coal ash, CaCO ₃ , Fe
It is possible to prevent the ash of petroleum coke from adhering to the gasification furnace wall by being captured by ₂ O ₃ or the like and flowing down together.

However, the use of inexpensive iron concentrate, which is easily available as Fe ₂ O ₃ , raises a new problem. That is, since iron concentrate is discharged from the flotation process of copper refining, it is in a humid state.For example, when stored in a container such as a silo, it adheres to the take-out port or forms a bridge in the silo and blocks it. There is a handling problem that it is difficult to take out of the silo because it is easy to handle.

[0008] The present invention has been made in view of the above-mentioned problems, and is intended to improve the handling of inorganic minerals such as fly ash, CaO, and iron ore, which are no longer required in coal-fired power plants, as flux. While solving the difficulty, iron concentrate having a large specific gravity is added to a bentonite slurry obtained by adding bentonite to water in advance to obtain an iron concentrate slurry having a uniform concentration, and then petroleum coke It is an object of the present invention to provide a method for producing a petroleum coke slurry in which a petroleum coke slurry is obtained by supplying the same to a wet pulverizer together with fly ash, CaO and the like, and pulverizing and mixing the resultant.

[0009]

In order to achieve the above-mentioned object, the present invention provides a method for converting petroleum coke slurry into a slurry state and subjecting the supplied petroleum coke slurry to gasification by a partial oxidation reaction in a gasifier. Ash that melts down the ash component of petroleum coke generated by the above method and CaO which is a melting point depressant of the fly ash
Is supplied to the inlet of the pulverizer together with water, and the bentonite slurry obtained by adding 2 to 10% by weight of bentonite with respect to water is added to 10 to 60% by weight of iron ash which is a melting point depressant of fly ash. The iron concentrate slurry obtained by adding and mixing the ore to the bentonite slurry was supplied to the inlet of the pulverizer to obtain a petroleum coke slurry.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method for producing a petroleum coke slurry according to the present invention will be described below with reference to FIGS.

FIG. 1 is a system diagram of an apparatus suitable for explaining the present invention, FIG. 2 is a diagram showing the relationship between the concentration of bentonite / water slurry at 30% by weight of iron concentrate and the viscosity of iron concentrate slurry, and FIG. FIG. 2 is a diagram showing the relationship between the mixing ratio of inorganic minerals and the ash adhesion rate with respect to the ash content of the present invention.

In FIG. 1, a petroleum coke 20 and an inorganic mineral 21 such as fly ash and CaO (or CaCO ₃ ) are put into a wet pulverizer 1 together with an appropriate amount of water to wet-pulverize the petroleum coke 20 to 100 μm. While being uniformly mixed with the inorganic mineral 21. Incidentally, granular CaO or CaCO ₃ is 1.4 mm.
Hereinafter, the iron concentrate is 0.5 mm or less (average particle size is 9 to 10 μm).
) Purchased and used to the extent that is already ground.

On the other hand, after a suitable amount of bentonite is added to water in advance to obtain a bentonite slurry, an iron concentrate, which is one of the inorganic minerals 21, is added and mixed, and the iron concentrate slurry obtained is wet-pulverized. The machine 1 is supplied.
That is, as shown in FIG. 2, when bentonite is added to an appropriate amount of water, a bentonite slurry as an aqueous solution is obtained.

However, if the amount of added bentonite is small, gelation does not sufficiently occur, and even if iron concentrate is added, the specific gravity is large (true specific gravity is about 4). It does not exhibit the effect of stability (it maintains a uniform concentration without separating sedimentation of bentonite, water and iron concentrate without sedimentation separation). Conversely, if the amount of added bentonite is too large, gelation proceeds and the bentonite slurry impairs fluidity.

In consideration of such a phenomenon, when the iron concentrate is mixed with the bentonite slurry, it is desirable to add 2 to 5% by weight of bentonite to water. Also, after adding the bentonite, it takes about 12 to 16 hours until the bentonite swells and gels. Therefore, as shown in FIG. 1, two adjusting tanks 30a and 30b are installed in advance. The semi-continuous supply of the iron concentrate slurry to the supply tank 35 is possible by appropriately switching the individual switching valves 37a and 37b as needed. Note that the supply of the iron concentrate slurry from the supply tank 35 to the wet mill 1 is performed by a pressure pump not shown.

When the petroleum coke 20, the inorganic mineral 21 such as fly ash and CaO (or CaCO ₃ ), and the iron concentrate slurry are supplied to the wet crusher 1 together with a suitable amount of water, the wet crusher 1 crushes and mixes the mixture. To produce a petroleum coke slurry. These petroleum coke slurries are supplied to the slurry tank 3 through the line 22.

The criteria for adding the inorganic mineral 21 to be added to the petroleum coke 20 as a flux for producing the petroleum coke slurry are as follows from practical studies. That is, the flux of the inorganic mineral can be mixed at a ratio of 3 to 20 parts by weight with respect to 1 part by weight of the ash component in the petroleum coke 20. This is petroleum coke 2
In order to prevent the adhesion and deposition of the ash of 0, if the inorganic mineral content is 3 parts by weight or less, the melting point temperature of the flux in the reducing atmosphere is 1 even if the mixing ratio of the flux is changed.
Although the temperature is 300 ° C. or lower, the relative amount of the flux is reduced, so that the cleaning power for cleaning the ash in the petroleum coke 20 becomes insufficient.

On the other hand, at 20 parts by weight or more, even if the mixing ratio of the flux changes, the melting point temperature under the reducing atmosphere becomes 1300 ° C. or less, but the relative amount of the petroleum coke 20 decreases. Carbon content also decreases. If an attempt is made to maintain the gasification operation temperature of the petroleum coke 20 at 1250 to 1450 ° C. in such a state, unnecessary CO ₂ gas increases, the ratio of effective gas components decreases, cold gas efficiency deteriorates, and production efficiency decreases. Will be. For this reason, it is preferable to mix the inorganic mineral flux at a ratio of 3 to 20 parts by weight with respect to 1 part by weight of ash in petroleum coke.

Further, the content of the inorganic mineral 21 is generally at least 40% by weight of fly ash,
It is desirable that the content be 25% by weight or less and 10% to 60% by weight of iron concentrate.
The melting point temperature of fly ash is 1120 to 1280 when the weight%, CaO 20% by weight, and iron concentrate 30% by weight are used.
° C.

This is because CaO and iron concentrate (mainly composed of Fe ₂ O ₃ ) are added as melting point depressants for fly ash. In particular, when CaO is added, if the mixing ratio to fly ash is 40% by weight or more. The CaCO ₃ dissolved in the water treatment line system in the post-process of the gasification furnace 6 precipitates due to a decrease in solubility as the water temperature rises, or the CaCO ₃ precipitates or deposits and the line is easily clogged.
The mixing ratio of aO to fly ash is at most 30.
It is desirable that the content be not more than% by weight.

In order to reduce the amount of CaO added as much as possible, iron concentrate may be used as a melting point depressant instead of CaO. However, the maximum addition amount of iron concentrate should be at most 60% by weight or less. desirable. The reason is that, when the amount of iron concentrate added is 60% by weight or more, the viscosity of the molten slag in the gasification furnace 6 increases and the fluidity of the slag deteriorates, and the slag melts the wall surface of the gasification furnace 6. Without flowing, a considerable amount of slag adheres and accumulates on, for example, the wall surface of the gasification furnace 6 and the throat portion 9, and stable long-term operation becomes difficult. Therefore, in this embodiment, the petroleum coke 2
As a flux to be added to 1 part by weight of the ash content in 0, for example, 50% by weight of fly ash, CaO2
0% by weight and 30% by weight of iron concentrate are supplied to the wet pulverizer 1 together with the petroleum coke 20, and a petroleum coke slurry with high storage stability can be produced by pulverization and mixing.

In the slurry tank 3, the wet crusher 1
To supply petroleum coke 20 with inorganic minerals 21
While the petroleum coke slurry obtained by grinding and mixing to an appropriate particle size is temporarily stored, mixing and stirring are performed,
Gasification raw material slurries are produced as petroleum coke slurries having a uniform concentration.

The gasification raw material slurry is sent to the gasification furnace 6 by the slurry pump 4 in the slurry tank 3. The gasifier 6 is provided with a burner 5 at the top, where the petroleum coke slurry is converted to a theoretical combustion oxygen amount of 4%.
The gas is supplied by spraying to the gasification furnace 6 together with oxygen in an amount of 0 to 60%, and gasification by partial oxidation is performed at a temperature of 1250 to 1450 ° C.

In this case, the pressure in the gasification furnace 6 is 20 to 8
It is set to about 0 atm. A reaction chamber 7 is formed by lining the upper part of the gasification furnace 6 with a refractory 7a. Further, a quenching chamber 8 is provided below the gasification furnace 6,
The reaction chamber 7 and the quenching chamber 8 communicate with each other through a throat section 9.
A water line 13 for sending water for gas quenching is opened in the quenching chamber 8 so that water is supplied to an appropriate water level.

The cooling water is provided coaxially with a cylindrical dip tube 10 and a draft tube 11 whose lower ends are immersed in the water. Therefore, the gas generated in the reaction chamber 7 passes through the throat section 9 and the dip tube 10 and is blown into the water in the quenching chamber 8, and thereafter, the gas outlet 14 a provided in the region above the water surface of the quenching chamber 8. Through the gas line 14 to a subsequent dust removal facility or the like.

When gas is blown into water in the quenching chamber 8, ash and unburned carbon generated when gasifying the petroleum coke 20 containing inorganic minerals 21 are mixed with water and quenched. Fine slag, which is relatively fine particles, is collected by water, and a slurry containing them is generated. This slurry is taken out from a line 15 connected to the side wall of the quenching chamber 8. From the lowermost line 16 of the quenching chamber 8, a slurry containing relatively coarse particles called coarse slag is taken out.

A method for producing a petroleum coke slurry supplied to the gasifier configured as described above will be described.

First, Table 1 shows typical elemental analysis values of the petroleum coke 20 used in this example, ash components of the petroleum coke, and ash melting point temperatures of the ash.

[0029]

[Table 1]

Next, according to the present invention, the petroleum coke 20
Minerals 21 which are mixed with water and prevent adhesion to the gasification furnace wall include fly ash generated from a boiler of a coal-fired power plant (collected by an electric dust collector, etc.), CaO and iron concentrate, etc. Table 2 shows the composition of fly ash obtained from the coal combustion of representative wallara coal and kutai coal among the inorganic minerals, and Table 3 shows the composition of iron concentrate.

[0031]

[Table 2]

[0032]

[Table 3]

First, the case where only the petroleum coke 20 is gasified will be described. 0.1- in petroleum coke 20
It contains 1.5% of ash, and further contains vanadium in the ash.

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

In order to prevent the adhesion and accumulation of the ash content of the petroleum coke 20, the inorganic mineral 21 shown in Tables 2 and 3 was prepared by applying the flux of the inorganic mineral 21 to 1 part by weight of the ash content in the petroleum coke 20. About 3 to 20 parts by weight are mixed, but if it is 3 parts by weight or less, the flux melting point temperature under the reducing atmosphere becomes 1300 ° C. or less even if the mixing ratio of the flux changes, but the relative amount of the flux decreases. Therefore, the cleaning power for cleaning the ash in the petroleum coke 20 becomes insufficient.

When the mixing ratio of the flux is changed to 20 parts by weight or more, the melting point temperature in the reducing atmosphere becomes 1,300 ° C. or less, but the petroleum coke 20
, The carbon content also decreases. Under these conditions, the gasification operation temperature of petroleum coke 20
If the temperature is kept at 1450 ° C., the ratio of the effective gas component decreases, the cold gas efficiency deteriorates, and the production efficiency decreases. In order to solve the problem, the flux of the inorganic mineral 21 was added to 1 part by weight of the ash in petroleum coke,
It is desirable to mix about 5 to 10 parts by weight.

As a melting point depressant of fly ash added to petroleum coke 20 as inorganic mineral 21 in this case, fly ash 50% by weight, CaO
The melting point temperature was 1120 ° C. in the case of 20% by weight and 30% by weight of iron concentrate. However, fly ash used was obtained by burning a mixture of wallara coal and kutai coal in a steam generating boiler.

Even if CaO and iron concentrate are added as fly ash melting point depressants, limestone (CaCO 3) supplied together with petroleum coke is reduced because the gasification reaction zone is in a reducing atmosphere. Lime (Ca
With become O), Fe2 O ₃ also becomes FeO.

In particular, if the supplied Fe ₂ O ₃ does not become FeO but remains in the gasification furnace 6 as Fe ₂ O ₃ , the bricks on the gasification furnace wall are attacked, the bricks are licked, and replacement is quick. However, such a problem does not occur because Fe ₂ O ₃ becomes FeO in a reducing atmosphere.

In order to prevent the ash in the petroleum coke 20 from adhering to the gasification furnace wall, data as shown in FIG. 3 was obtained. That is, as shown in FIG. 2, a gasification operation temperature of 1400 ° C. and a pressure of 38 kg / cm ² G (3.8 × 1
( ⁶ Pa), the ash content (1 in petroleum coke 20)
(Parts by weight), the rate of adhesion of the ash to the gasification furnace wall tended to decrease as the proportion of the inorganic mineral added increased.

Therefore, according to the present invention, based on the data shown in FIG.
Eliminate the ash adhesion to the gasification furnace wall, or reduce the ash adhesion to the gasification furnace wall to 2% or less so that long-term continuous operation is possible even if adhesion occurs. Therefore, the addition amount of the inorganic mineral is set to 3 to 20 parts by weight with respect to 1 part by weight of the ash content in the petroleum coke 20.

In the present invention, the temperature T 0 of the partial oxidation reaction in the reaction chamber 7 is determined by the melting point temperature T of the inorganic mineral ash.
It is preferably 30 to 100 ° C. higher than that. That is, the temperature T0 in the reaction chamber 7 is equal to or higher than (T + 30) ° C.
(+100) ° C. or lower.

As described above, when the petroleum coke 20 is used as a gasification raw material and a partial oxidation reaction is performed under the above-described operating conditions, a product gas such as CO, H ₂ , or CO ₂ is obtained.
A method for producing an inorganic mineral 21 as a flux to be added in order to prevent the ash content of the petroleum coke 20 which is a problem in this case, particularly an iron concentrate slurry which is particularly difficult to handle will be described.

First, the case where 60% by weight of iron concentrate and 40% by weight of bentonite slurry are mixed in the adjusting tank 30a will be described. First, water is supplied to the adjustment tank 30a,
Then, after adding bentonite and swelling, a highly viscous gel is formed for 15 hours. In this case, the total amount of water and bentonite is 40% by weight, and bentonite is added so as to be 5% by weight with respect to water to produce a bentonite slurry.

In the present invention, the amount of bentonite added to water is in the range of 2 to 10% by weight, but if it is less than 2% by weight, the amount of gel formed is insufficient, and the sedimentation, aggregation and consolidation of iron concentrate And it is difficult to obtain a homogeneous slurry having high storage stability. Conversely, if the content is 10% by weight or more, the iron ore gelled in the slurry itself forms a strong agglomerate, and the fluidity of the bentonite slurry is impaired. As a result, the slurry concentration of petroleum coke cannot be increased. . For this reason, the desirable addition amount of bentonite to water is 4-7.
% By weight.

Following the bentonite slurry thus produced, iron concentrate was added in an amount of 60% by weight, and the mixture was stirred by a stirrer (not shown) so as to have a uniform concentration and a viscosity of 800 cp. Obtain iron concentrate slurry. However, such iron concentrate slurry does not form a sedimentary layer even when left for a long period of time. Adjustment tank 3
0b is performed in the same manner as the adjustment method in the adjustment tank 30a, but the capacity of the adjustment tanks 30a and 30b is
It is desirable that the iron concentrate slurry be large enough to be continuously supplied from the supply tank 35 to the wet mill 1. Therefore, the supply of the iron concentrate slurry from the adjustment tanks 30a and 30b to the supply tank 35 is performed semi-continuously while switching the switching valves 37a and 37b.

In particular, when the amount of bentonite added to water exceeds 8% by weight, the viscosity of the bentonite slurry sharply increases. This is due to the swollen bentonite, as described above, and is forcedly stirred by a stirrer. The viscosity is reduced by loosening the swollen bentonite.

[0048]

As is apparent from the above description, in the present invention, in order to prevent the ash generated by the partial oxidation reaction of the petroleum coke slurry from adhering and accumulating in the reactor, the above-mentioned flux is used. The ash component is flowed down, but of the CaO and the iron concentrate added as the melting point depressant of the fly ash used as the flux, the iron concentrate is added to the bentonite slurry and mixed to prepare an iron concentrate slurry. This facilitates the handling of the iron concentrate, and further prevents sedimentation and separation at the time of addition, so that an iron concentrate slurry having a uniform concentration can be obtained.

[Brief description of the drawings]

FIG. 1 is a system diagram of an apparatus suitable for explaining the present invention.

FIG. 2 is a graph showing the relationship between the concentration of bentonite / water slurry and the viscosity of iron concentrate slurry at 60% by weight of iron concentrate.

FIG. 3 is a diagram showing a relationship between a mixing ratio of an inorganic mineral to an ash component in petroleum coke and an ash adhesion rate.

[Explanation of symbols]

 Reference Signs List 1 wet mill 3 slurry tank 5 burner 6 gasifier 7 reaction chamber 8 quenching chamber 9 throat section 20 petroleum coke 21 inorganic mineral 22 line 30a, 30b adjustment tank 35 supply tank 37a, 37b switching valve 40 supply valve

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Kotaro Katagiri 1-12-32 Nishihonmachi, Ube City, Yamaguchi Prefecture Ube Industries, Ltd. Ube Head Office

Claims (1)

[Claims] When a petroleum coke is made into a slurry state and gasified by a partial oxidation reaction in a gasifier, a fly ash which melt-flows an ash component of the petroleum coke produced by the reaction of the supplied petroleum coke slurry is provided. The fly ash melting point depressant CaO is supplied to the inlet of the pulverizer together with water, and the bentonite slurry obtained by adding 2 to 10% by weight of bentonite to water is mixed with fly ash melting point depressant. There are 10
A method for producing a petroleum coke slurry, wherein an iron concentrate obtained by adding and mixing iron concentrate of about 60 wt% to the bentonite slurry is supplied to an inlet of the pulverizer to obtain a petroleum coke slurry. .