JPH07316570A - Process for producing pitch/water slurry fuel having high desulfurization property and desulfurization of combustion exhaust gas of the fuel - Google Patents

Abstract

PURPOSE:To obtain a slurry fuel capable of removing SOx generated in combustion with a sulfur-absorbing agent by mixing a pitch melt with a powdery sulfur-absorbing agent, further adding the pitch to the mixture to adjust the content of the sulfur-absorbing agent and pouring the product into water. CONSTITUTION:The molar ratio of sulfur in a pitch melt (having a softening point of 80-180 deg.C) to a sulfur-absorbing agent 6 is adjusted to 6-8 by a mixer 2 and the molar ratio of the sulfur to the sulfur-absorbing agent is adjusted to 1-2 by adding additional pitch melt 100 to mixer 20. The pitch melt supplied to a receiving tank 3 is sent to a high-shear dispersion apparatus 4 supplied with water or hot water 7 and the produced pitch/water slurry having a water content of 30-40wt.% is supplied to a combustion furnace 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to pitch / rich desulfurization
The present invention relates to a method for producing a water slurry fuel. For more details,
A method for producing a pitch / water slurry fuel rich in desulfurization, in which molten pitch containing a sulfur absorbent is poured into water or heated water under normal pressure or pressure to produce a pitch / water slurry fuel, and combustion of the fuel The present invention relates to a method for desulfurizing exhaust gas.

[0002]

2. Description of the Related Art In recent years, from the viewpoint of fuel cost reduction, Coal Water Mixture (CWM), in which pulverized coal is dispersed and mixed in water, in place of conventional A heavy oil fuel and C heavy oil fuel,
Water-emulsion such as coal oil mixture (COM), in which pulverized coal is dispersed and mixed in oil, and petroleum-based oil, such as asphalt, has come to be used as fuel for boilers and the like. In oil refineries, heavy crude oil,
Various cracking equipment to lighten atmospheric pressure and decompression residue will be installed, and petroleum pitch-like substances (hereinafter referred to as pitch) produced as a by-product from various equipment will be used as fuel for boilers. Became. Since this pitch is very heavy and has a high melting point, it is difficult to burn it directly. As disclosed in Japanese Patent Publication No. 2-16959, the pitch is supplied as fuel in the form of water slurry. Has been done. Generally, the pitch contains about 3 to 8% of sulfur, and in order to use the pitch as a fuel, it is necessary to install a desulfurization device from the viewpoint of environmental pollution. Hitherto, a so-called lime-gypsum method which is a wet method capable of desulfurization of 95% or more has been adopted as one of desulfurization devices. However, this method has drawbacks such as high equipment cost, operating cost, large amount of water, waste water treatment facility, and large energy consumption. Therefore, from the viewpoint of energy saving and economical efficiency, an attempt has been made to increase the desulfurization efficiency by a semi-dry method or a dry method instead of the desulfurization method, and one example thereof is as follows. That is, as a method of replacing the lime-gypsum method, in a pulverized coal cooking boiler, dry desulfurization referred to as in-furnace desulfurization in which a sulfur absorbent such as quick lime and calcium carbonate is directly mixed in the furnace and burned, Dry desulfurization,
A method combining in-furnace desulfurization and semi-dry desulfurization is being studied. For example, regarding the semi-dry desulfurization, Kawasaki Heavy Industries Tech. No. 109 (1994) pp. 39-46, and the method combining the in-furnace desulfurization and the semi-dry desulfurization, Mitsubishi Heavy Industries Tech., Vol. 29, No1 (1992-1), 60-6
Published on page 3. Regarding the in-furnace desulfurization (primary desulfurization) in the above two documents, desulfurization is explained by the reaction formula shown below,
The desulfurization rate is described as 20 to 50% in the former document and 40 to 60% in the latter document. CaCO ₃ → CaO + CO ₂ (1) CaO + SO ₂ + 1 / 2O ₂ → CaSO ₄ (2) Further, in the latter document, from the top of the section 3.1.1 Basic test on page 62, 4 to 6 In the second line, it is stated that high uniform desulfurization efficiency may be obtained even if limestone is charged into the furnace if uniform mixing is possible from the relationship between the Ca / S molar ratio, residence time and desulfurization rate. At the furnace C
It is described that at the a / S molar ratio of 2.2, the in-furnace desulfurization rate of 40 to 45%, the semi-dry desulfurization rate of 65 to 70%, and the total desulfurization rate of the combination of both achieved 80 to 85%. From the description in these documents, it is expected that uniform mixing will be difficult when charged into the furnace. On the other hand, no similar literature was found to be used for petroleum-based pitches for coal-based ones, which suggests that uniform mixing is difficult when charged in a furnace.

[0003]

The above prior art has the following problems to be improved. 1) A wet desulfurization device was necessary only by supplying pitch in the form of water slurry as fuel, which is the method disclosed in Japanese Patent Publication No. 2-16959. 2) In the pulverized coal cooking boiler, the sulfur absorbent is directly charged into the combustion furnace for desulfurization in the furnace, but since uniform mixing is difficult, the desulfurization rate remains at 60% or less, and the desulfurization rate is improved. Requires an excess of sulfur absorber. Therefore, there has been awaited a technique in which the required amount of the sulfur absorbent is small and the desulfurization rate can be improved by desulfurization in the furnace. 3) Petroleum-based pitch has not been carried out because it is difficult to mix the sulfur absorbent evenly when it is charged into the furnace. Further, in the combination of 1) and 2) above, it is simply due to the desulfurization in the furnace. The desulfurization rate cannot be expected to improve. 4) The total desulfurization rate in which the in-furnace desulfurization and the semi-dry desulfurization were combined was only 80 to 85%. As described above, in the combination of in-furnace desulfurization and semi-dry desulfurization, pitch is supplied in the form of water slurry as fuel,
At the same time, there has been awaited a technique capable of performing desulfurization in an energy-saving and economical manner. It is an object of the present invention to provide means for solving the above problems. More specifically, the molten pitch containing the sulfur absorbent is poured into water or heated water under normal pressure or pressure to make pitch / water slurry fuel, which is generated during combustion when this fuel is supplied to the combustion furnace. It is an object of the present invention to provide a method for producing a pitch / water slurry fuel having a high desulfurization property, in which SOx to be removed can be removed with high efficiency by a sulfur absorbent. Furthermore, it aims at providing the desulfurization method of the combustion exhaust gas of this fuel.

[0004]

[Means for Solving the Problems] The present inventors have found that unless a sulfur absorbent such as quick lime, calcium hydroxide, calcium carbonate, magnesium hydroxide, magnesium carbonate, etc. is uniformly dispersed and mixed in the molten pitch, the sulfur absorbent is mixed. It is difficult to produce a pitch / water slurry fuel with the pitch containing the above, further, the desulfurization efficiency in the furnace does not increase, and the desulfurization efficiency in the furnace is dramatically improved depending on the degree of dispersion of the sulfur absorbent. Based on this finding, based on this finding, a diligent study was made on a method for uniformly dispersing and mixing a sulfur absorbent in pitch and a method for producing a water-slurry fuel rich in desulfurization in which the pitch was mechanically finely dispersed in water. As a result, the present invention has been achieved. That is, the present invention is a method for producing a pitch / water slurry fuel rich in desulfurization characteristics, which is characterized by comprising the following three steps A, B and C. (A) In the mixer, the raw material pitch having a softening point of 80 ° C. or higher and 180 ° C. or lower is kept in a molten state, and the powdery sulfur absorbent is adjusted to a sulfur content in the raw material pitch and the molar ratio of the sulfur absorbent to 6 to 8. So as to be added to the pitch and uniformly dispersed to produce a pitch containing a sulfur absorbent. Step (B) A raw material pitch is further added to the pitch containing a sulfur absorbent obtained in Step A, and the pitch is uniformly melted. Step B of adjusting the molar ratio of the sulfur content and the sulfur absorbent in the raw material pitch (C) The molar ratio-adjusted pitch obtained in Step B was subjected to normal pressure or pressurization in a molten state. Process C of producing pitch / water slurry fuel by pouring into water or heated water and uniformly mixing it. Further, as a result of further studies by the present inventors, as a result of combustion of the pitch / water slurry fuel produced by the above method and rich in desulfurization property. By subjecting exhaust gas to specific treatment It found that attained desulfurization efficiently flue gas. That is, the present invention is a pitch / water slurry rich in desulfurization, characterized in that the combustion exhaust gas of pitch / water slurry fuel rich in desulfurization produced by the above method is introduced into a spray tower and brought into contact with water in cocurrent. This is a method for desulfurizing combustion exhaust gas of fuel.

In the present invention, the raw material pitch is a residue obtained by subjecting atmospheric pressure residue, reduced pressure residue and the like to thermal decomposition regardless of the type of crude oil or the like, and having a softening point of 80 ° C. or higher and 180 ° C. or lower. Used. Although the pitch varies depending on the softening point, it means that the handling temperature is maintained at 300 ° C. or less, and the one having a viscosity of 500 centistokes or less is preferable in operation. Although it depends on the softening point of the pitch, it is preferable to avoid the pitch maintained at a handling temperature of more than 300 ° C., as the volatile components remaining in the pitch volatilize and the viscosity increases with the passage of time. The sulfur absorbent used in the present invention is, for example, powdered compounds such as quick lime, calcium hydroxide, calcium carbonate, magnesium hydroxide, magnesium carbonate, etc., and these may be commercially available chemicals, and they should be fine. Are preferred, but are not particularly limited thereto. These can be used alone or in combination of two or more.

Each step of the method for producing a pitch / water slurry fuel rich in desulfurization property of the present invention will be described below. In step A, the sulfur absorbent is added to the pitch. The sulfur content and the sulfur absorbent contained in the molten pitch are added so that the molar ratio is 6 to 8, and they are mixed uniformly. If the molar ratio is less than 6, when the molar ratio of the sulfur content and the sulfur absorbent contained in the molten pitch is adjusted to 1-2 in the pitch separately prepared in step B, the amount of processing to be adjusted becomes small. . If the molar ratio exceeds 8, the dispersion may not be improved even if the mixing takes a long time. In this case, even if the molar ratio of the molten pitch and the sulfur absorbent is finally adjusted to 1 to 2 in step B, the dispersion is not improved. Increasing the mixing time to improve dispersion is not preferable because it tends to reduce volatile components in the pitch. Here, to make it uniform means to prevent the sulfur absorbent from agglomerating and uniformly disperse it in the pitch as primary particles. The method for uniformly dispersing and mixing the sulfur absorbent in the above pitch will be described in detail later, but it can be achieved by putting a plurality of ball-shaped substances in a mixer and stirring. A ball bearing may be used as the ball-shaped substance, but it does not have to be a true sphere like a ball bearing, so long as it is a so-called spherical shape, and a diameter of 1 mm to 5 mm is used. The material used is magnetic, glassy, metallic or the like, but a commercially available one represented by a ball bearing, a stainless steel ball, an iron ball, an alumina ball or the like may be used. In step C, when a uniform mixture of pitch and a sulfur absorbent is mixed with atmospheric pressure or pressurized water or hot water, precipitation is prevented due to aggregation of pitch particles, and fluidity of the pitch / water slurry fuel is improved by an interface. 0.2-1% by weight of activator
It is good to add. Surfactants for this purpose, ether type alkylallyl polyoxyethylene ether, alkylallyl formaldehyde condensed polyoxyethylene ether, polyoxyethylene polyoxypropyl alkyl ether, etc., ether ester type polyoxyethylene ether glycerin ester, Examples thereof include ester-type polyethylene glycol fatty acid esters such as polyoxyethylene ether sorbitan ester, glycerin ester, sorbitan ester, and propylene glycol ester.

Through the steps described above, the desulfurizing rich pitch / water slurry fuel of the present invention is manufactured.

Next, the desulfurization method of the combustion exhaust gas of the pitch / water slurry fuel rich in desulfurization property of the present invention will be explained.
By burning the pitch / water slurry fuel of the present invention, in-furnace desulfurization for desulfurization in the furnace is performed. Either in-furnace desulfurization alone or a combination of desulfurization of combustion exhaust gas discharged outside the furnace is adopted. In the latter case, which is called a semi-dry type, in the present invention, desulfurization of the flue gas of the pitch / water slurry fuel is achieved by contacting with water in parallel in the spray tower. The amount of spray water needs to be supplied such that the temperature difference between the exhaust gas temperature at the outlet of the spray tower and the water vapor saturation temperature of the exhaust gas is 10 ° C. or higher, preferably 15 ° C. or lower. When the temperature difference between the exhaust gas temperature at the spray tower outlet and the steam saturation temperature of the exhaust gas becomes smaller, the desulfurization rate improves. However, if the temperature is lower than 10 ° C., the desulfurizing agent may adhere to the inner wall of the spray tower or the exhaust gas duct tower downstream, and may cause a situation of clogging, which may prevent stable operation. On the other hand, if the temperature difference exceeds 15 ° C, the desulfurization rate decreases, so it is preferable to avoid it. The spray shape is designed so that the spray angle can be selected according to the diameter and height of the spray tower.

The features of the present invention will be described below in more detail with reference to the drawings. FIG. 1 shows a conceptual diagram of a method for producing a pitch / water slurry fuel rich in desulfurization property of the present invention. Note that FIG.
Then, the process A is performed by the mixer 2, and the process B is performed by the mixer 20.
However, it is also possible to perform both steps A and B in the mixer 2, and it is possible to perform not only the continuous method but also the batch method. It goes without saying that you can do it. Further, as the desulfurization method of the combustion exhaust gas, a combination of in-furnace desulfurization and a semi-dry method using a spray tower will be described, but it goes without saying that the present invention can be performed only by in-furnace desulfurization. First, a method for uniformly dispersing and mixing the sulfur absorbent in the pitch in the above-described step A will be described below. The pitch maintained at 300 ° C in the pitch melting tank 1 having a heating function passes through the line 40 and the line 41 and is 300 ° C by the pump 8.
Is supplied to the mixer 2 maintained at. A mixer 2 having a stirrer 30 contains a plurality of balls 12 having a diameter of 1 mm to 5 mm. This number varies depending on the continuous system, the batch system, and the size of the mixer 2, but is selected from 15 to 70% of the mixer 2 in terms of volume. Stirrer 30
Has a plurality of stirring blades. The stirring speed varies depending on the size and shape of the mixer 2, but is 300 to 2000 rp.
selected from m. A conceptual diagram of the mixer 2 having the stirrer 30 and the mixer 20 having the stirrer 31 is shown in FIG. Mixer 2 shown in FIG.
The main part is composed of a jacket 200, an agitator 30 including an agitator shaft 70 and an agitator arm 80, a drive motor 60, a pump 9, a plurality of balls 12, and the like. A plurality of agitator arms 80 are provided orthogonally to the agitator shaft 70, and are pinned so that they can be removed. In order to improve the dispersion efficiency, a plurality of the balls 12 described above are put in the mixer 2.
The stirrer 30 is driven by a so-called upper drive system which is performed from the upper part of the tank. A valve 300 with a screen is attached to the bottom of the tank, which allows discharge and circulation of the treated material. In the mixer 2 shown in FIG. 1, the molar ratio of sulfur to sulfur absorbent 6 in the pitch is 6 to 8. The sulfur absorbent 6 is charged so that In the mixer 2, a stirring time of about 30 to 60 minutes is selected, although it varies depending on the size, shape and stirring strength of the mixer 2, that is, the number of rotations. If it is less than 30 minutes, the agglomeration of the sulfur absorbent may not be broken, and the particles may not be uniformly dispersed in the pitch as primary particles. The effect is almost unchanged even after 60 minutes. Moreover, in order to increase the residence time in the mixer 2, the line 42, the pump 9, and the line 43
It can be recycled through the line 44 and the line 44, and the amount thereof may be selected from 10 to 60%, although it depends on the softening point of the pitch.

Next, the step B will be described. In the step A, the molar ratio of the sulfur content in the pitch to the sulfur absorbent 6 is 6 to
The product adjusted to 8 is supplied to the mixer 20 through the line 43, the line 45, and the line 46 by the pump 9. The mixer 20 is supplied from the line 100 with a molten pitch similar to that held in the pitch melting tank 1 from another place not shown in the drawing, and the sulfur content in the pitch and the sulfur absorbent 6 are supplied. The molar ratio is adjusted to 1-2. In the mixer 20, the size, shape of the mixer 20,
Although it depends on the stirring intensity, that is, the number of rotations, the stirring time may be selected to be approximately 1 to 2 minutes. Also,
In order to increase the residence time in the mixer 20, the line 47,
It can be recycled through the pump 10 and the line 48, and its amount is selected from 10 to 60%. The sulfur content of the pitch and the sulfur absorbent 6 whose molar ratio is adjusted to 1 to 2 are supplied to the receiving tank 3.

Next, the step C will be described. The pitch supplied to the receiving tank 3 has a water content of 30 to 40% by weight.
Water adjusted to be a water slurry or heated water 7
Is fed to the high shear type disperser 4 to be mechanically finely dispersed in water to become a pitch / water slurry fuel rich in desulfurization, and supplied to the combustion furnace 5 through the line 55.

Finally, the desulfurization method of the combustion exhaust gas of the pitch / water slurry fuel rich in desulfurization property of the present invention will be described. The pitch / water slurry fuel rich in desulfurization supplied to the combustion furnace 5 in the step C is burned in the combustion furnace 5. The combustion exhaust gas generated at this time is supplied to the spray tower 500 through a line 600. Line 6 in the spray tower 500
Water is supplied from 10, and sprayed uniformly by the spray 90 to form water droplets, which come into contact with the combustion exhaust gas in parallel flow, and SO _X is absorbed by the desulfurizing agent moistened with water. The combustion exhaust gas absorbs SO _X and is desulfurized, and then is discharged to the outside of the system through a line 620.

Although each operating condition has been described above, continuous operation, semi-batch operation, batch operation, etc. may be carried out fully automatically in consideration of the influence of each operating factor, or semi-automatically and manually. It goes without saying that it is good.

[0014]

[Function] Conventionally, since the solid raw material and the sulfur absorbent are separately supplied, the contact efficiency between the sulfur oxide and the sulfur absorbent generated due to the oxidation of the sulfur in the solid raw material is poor. The reaction of (2) was difficult to occur and the desulfurization efficiency was poor. On the other hand, in the present invention, since the sulfur absorbent is uniformly dispersed in the molten pitch, the contact efficiency between the sulfur oxide and the sulfur absorbent generated at the time of combustion is good. It is estimated that the desulfurization efficiency is improved as shown by the difference.

[0015]

EXAMPLES The features of the present invention will be specifically described below with reference to examples, but the present invention is not limited thereto. Example 1 Pitch having a softening point of 120 ° C. obtained by thermal decomposition of an Iranian heavy vacuum residual oil was used as a raw material. 300 ° C
It was supplied to the mixer 2 while being maintained at. The pitch contained 8% of sulfur. In step A,
The volume of mixer 2 was 28 liters and had 90 kg of 2.4 mm balls. The rotation speed of the stirrer 30 is 1000
It was rpm. The pitch supplied from the molten pitch tank 1 to the mixer 2 was 3.7 liters / min, while the sulfur absorbent 6 supplied calcium hydroxide to the mixer 2 at a rate of 3.1 kg / min. By the above operation, the molar ratio of the sulfur component contained in the molten pitch to the sulfur absorbent was set to 6. The stirring time was 30 minutes, and the recycle amount in the mixer 2 was 30% of the supply pitch. In step B, the mixer 20
The condition was set to be the same as that of the process A except that the pitch was newly supplied from the line 100 and the molar ratio of the sulfur content and the sulfur absorbent contained in the molten pitch was 2. The pitch obtained above is transferred to the receiving tank 3 and 1 minute per minute from the receiving tank 3.
Water was simultaneously fed to the high shear disperser 4 at a rate of 4.1 kg to obtain a 30% pitch / water slurry fuel. Three
Table 1 shows the results of burning 0% pitch / water slurry fuel in the combustion furnace 5. Example 2 Example 1 was repeated except that the molar ratio of the sulfur content and the sulfur absorbent contained in the molten pitch in step A of Example 1 was changed from 6 to 8. The results are shown in Table 1. Example 3 Example 1 was repeated except that the molar ratio of the sulfur content and the sulfur absorbent contained in the molten pitch in step B of Example 1 was changed from 2 to 1. The results are shown in Table 1. Example 4 The pitch / water slurry fuel concentration of Example 1 was changed from 30% to 4
The same procedure as in Example 1 was repeated except that the content was changed to 0%. The results are shown in Table 1. Examples 5 to 8 Sulfur absorbent of Example 1 from calcium hydroxide, quicklime, calcium carbonate, magnesium hydroxide,
The same procedure as in Example 1 was carried out except that magnesium carbonate was used instead. The results are shown in Table 1. Example 9 The pitch / water slurry produced in Example 6 was supplied to the combustion furnace 5 at a flow rate of 50 kg / hour, and combustion exhaust gas of 290 Nm ³ /
Got the time. This combustion exhaust gas was supplied to the spray tower 500. At this time, water was sprayed so that the temperature difference between the exhaust gas temperature at the spray tower outlet and the steam saturation temperature of the exhaust gas was 15 ° C. The results are shown in Table 1. Example 10 The procedure of Example 9 was repeated except that the temperature difference between the exhaust gas temperature at the outlet of the spray tower and the steam saturation temperature of the exhaust gas in Example 9 was changed from 15 ° C to 10 ° C. The results are shown in Table 1. Comparative Example 1 Example 1 was repeated except that the molar ratio of the sulfur content and the sulfur absorbent contained in the molten pitch in Step A of Example 1 was changed from 6 to 9. The results are shown in Table 1. Comparative Example 2 The same operation as in Example 1 was carried out by stopping the driving of the stirrer 30 in step A of Example 1. The results are shown in Table 1.

Comparative Example 3 The procedure of Example 9 was repeated, except that the temperature difference between the exhaust gas temperature at the outlet of the spray tower and the steam saturation temperature of the exhaust gas in Example 9 was changed from 5 ° C to 15 ° C. The results are shown in Table 1. Comparative Example 4 The procedure of Example 9 was repeated, except that the temperature difference between the exhaust gas temperature at the outlet of the spray tower of Example 9 and the steam saturation temperature of the exhaust gas was changed from 15 ° C to 25 ° C. The results are shown in Table 1.

[0017]

[Table 1]

[0018]

As described above, according to the present invention, since the sulfur absorbent is dispersed in the pitch in two stages, the pitch / water slurry fuel in which the sulfur absorbent is uniformly dispersed can be produced. There is. (1) Since the pitch / water slurry fuel has a high desulfurization property, the desulfurization rate is high as compared with the conventional in-furnace desulfurization, and the desulfurization device is unnecessary. (2) The required amount of sulfur absorbent is reduced. (3) Since the pitch / water slurry fuel has a high desulfurization property, further desulfurization of combustion exhaust gas can be performed by providing a simple spray tower.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of a method for producing a pitch / water slurry fuel rich in desulfurization property of the present invention.

FIG. 2 is a conceptual diagram of a mixer according to the present invention.

[Explanation of symbols]

 1 Pitch Melt Tank 2, 20 Mixer 3 Receiving Tank 4 High Shear Disperser 5 Combustion Furnace 6 Sulfur Absorber 7 Water or Heated Water 8-11 Pump 12 Ball 25 Pitch Supply Port 30, 31 Stirrer 40-55, 100 Lines V1, V2 Valve 60 Drive motor 70 Agitator shaft 80 Agitator arm 95 Pitch containing sulfur absorbent 200 Jacket 300 Valve with screen 400 Slurry surface 500 Spray tower

Claims (6)

[Claims] 1. A method for producing a pitch / water slurry fuel rich in desulfurization characteristics, which comprises three steps of the following step A, step B and step C. (A) In the mixer, the raw material pitch having a softening point of 80 ° C. or higher and 180 ° C. or lower is kept in a molten state, and the powdery sulfur absorbent is adjusted to a sulfur content in the raw material pitch and the molar ratio of the sulfur absorbent to 6 to 8. So as to be added to the pitch and uniformly dispersed to produce a pitch containing a sulfur absorbent. Step (B) A raw material pitch is further added to the pitch containing a sulfur absorbent obtained in Step A, and the pitch is uniformly melted. Step B of adjusting the molar ratio of the sulfur content and the sulfur absorbent in the raw material pitch (C) The molar ratio-adjusted pitch obtained in Step B was subjected to normal pressure or pressurization in a molten state. Process C of producing pitch / water slurry fuel by pouring into water or heated water and uniformly mixing 2. The method for producing a pitch / water slurry fuel rich in desulfurization characteristics according to claim 1, wherein a plurality of ball-shaped substances are put in the mixer in the steps A and B. 3. The pitch having high desulfurization ability according to claim 1, wherein in step B, the raw material pitch is added so that the molar ratio of the sulfur content in the raw material pitch to the sulfur absorbent is 1 to 2. / Method for producing water slurry fuel. 4. The pitch having a high desulfurization property according to claim 1, wherein the sulfur absorbent is one or more mixtures selected from quick lime, calcium hydroxide, calcium carbonate, magnesium hydroxide and magnesium carbonate. /
Water slurry fuel manufacturing method. 5. The combustion exhaust gas of a pitch / water slurry fuel rich in desulfurization produced by the method according to claim 1 is introduced into a spray tower and brought into contact with water in a cocurrent flow. A method for desulfurizing combustion exhaust gas of a pitch / water slurry fuel, which is rich in desulfurization characteristics. 6. When the combustion exhaust gas is introduced into the spray tower and brought into contact with water in parallel flow, the temperature difference between the exhaust gas temperature at the spray tower outlet and the steam saturation temperature of the exhaust gas is 10 ° C. or more. The desulfurization method of combustion exhaust gas of a pitch / water slurry fuel rich in desulfurization property according to claim 5.