JPH0224876B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for stirring a mixture of coal and petroleum vacuum residue oil (asphalt) in which fine particles of coal have settled and accumulated in a tank.

Coal is a fossil fuel resource with the largest reserves and is attracting attention as an energy alternative to oil.

Coal is solid and inconvenient to handle, and it also contains ash, sulfur, nitrogen, etc., and to use it effectively, it is desirable to convert it into a clean energy source by liquefying or gasifying it.

On the other hand, due to environmental regulations, it has become difficult to use heavy oil, which is used as an energy source, as a fuel unless the sulfur concentration contained therein is reduced. Therefore, various processes have been developed to gasify heavy oil containing a large amount of heavy metals and remove the sulfur content.

Due to the above situation, in our country, raw materials handling,
From the perspective of storage and transportation, petroleum vacuum residue oil (asphalt), which is the heaviest part of crude oil and has the highest sulfur concentration, is mixed with coal to form a slurry and gasified with steam and oxygen to create an alternative energy source to natural gas. Development of a method to use it as a method is underway. Therefore, after mixing these petroleum-based vacuum residue oils (asphalt) and coal to form a slurry, a problem arises when the agitator is temporarily stopped and restarted several days later.

Conventionally, stirring devices for mixing powder and liquid are
There are various types, but in all of them, during storage, the coal (fine particles) in the slurry settles and accumulates due to the difference in specific gravity, forming a fixed layer (sediment layer). Therefore, in order to operate the agitator again, the temperature inside the tank must be raised to 200℃.
After raising the slurry to a higher level and lowering the viscosity of the slurry, the slurry was rotated, but due to the above-mentioned reasons, it was difficult to rotate the slurry. Therefore, in order to speed up the operation of the stirrer,
Up until now, the particle fixed layer deposited at the bottom of the tank was poked with a scraping rod from the slurry supply port, and the agitator was rotated after the entire layer had been softened. If this method is used, it will take around 16 hours to rotate the agitator in a tank with a slurry volume of 200 to 300, which is usually used, which is inefficient and at the same time makes the operation and operation system very poor. There are drawbacks.

In addition, with commonly used stirring devices equipped with a stirrer, due to the structure, installation position, rotation speed, etc. of the stirring blades, coal concentration distribution may occur in the tank height direction, particle sedimentation, and particle smearing. Phenomena such as adhesion appeared. If the material is supplied in these conditions, if a supply device, particularly a gear pump, is used to supply the solids, these solids will become clogged between the gear and the casing, causing problems such as stopping the supply.

The purpose of the present invention is to improve the above-mentioned drawbacks, locally stimulate and soften the coal particles in the slurry deposited in the lower part of the tank, accelerate the start-up of the main agitator, and at the same time reduce the amount of coal and petroleum-based vacuum residue. The purpose is to improve the mixing of oil (asphalt).

The present invention provides a method for stirring a mixture of coal in which fine particles of coal have settled and accumulated in a tank and petroleum-based vacuum residue oil, which comprises: a main stirrer that is vertically movable provided at the top of the tank; and a plurality of stirrers provided at the bottom of the tank. Using a tank with an auxiliary stirrer that can be moved up and down, the mixture is heated to 200°C or higher and stirred by the auxiliary stirrer until the mixture has a viscosity that allows the main stirrer to drive, and then stirred by the main stirrer. The method of stirring a mixture of coal and petroleum-based vacuum residue oil is characterized in that the above-mentioned drawbacks can be eliminated.

It is also possible to measure the viscosity of the deposited layer and automatically drive the auxiliary stirrer or the main stirrer based on a preset value.

Furthermore, in order to prevent coal concentration distribution and adhesion of particles within the slurry supply tank, such drawbacks can be eliminated by installing a circulation line returning to the tank side in the slurry supply line.

The present invention will be explained with reference to the drawings. 1 is tank 4
This stirrer 1 has a stirring blade 9 at the tip of a mandrel 10, and the mandrel 10 can be moved up and down in the tank 4 by a moving device 3. 2 is a pipe that supplies a slurry of coal (fine particles) and petroleum vacuum residue oil (asphalt) mixed in advance in a slurry adjustment tank (not shown) to tank 4; 5 is a slurry 6 supplied into tank 4; 7 is a viscosity detector installed on the outer wall of the tank 4 for measuring the viscosity of the slurry; 8 is a supernatant layer of the slurry;
is a plurality of auxiliary agitators installed on the lower side wall of the tank 4. This auxiliary agitator 8 also has a stirring blade 12 at the tip of a mandrel 11, and the mandrel 11 is moved up and down in the tank 4 by an auxiliary moving device 13. You can move to 14
is a controller for the agitator 1 and the auxiliary agitator 8, 15 is a circulation pipe that circulates the slurry in the tank 4, 16 is a slurry pump installed in the circulation pipe 15, and 17 is a circulation pipe between the tank 4 and the slurry pump 16. 15
Slurry on/off valve 18 installed in circulation pipe 15
The more branched slurry supply pipes 19 and 20 are on-off valves provided in the pipes 15 and 18, respectively, near the branch portions.

Now, the operation when starting the stirring device is to first heat the inside of the tank 4 (heating means not shown) to 200°C or higher, measure the viscosity of the slurry 6 with the viscosity detector 7, and then use the controller 14 of the stirrer to measure the viscosity of the slurry 6. Due to the signal from
The auxiliary moving device 13 of the auxiliary stirrer 8 installed at the bottom of the tank 4 is operated to stir the slurry 6 until the viscosity of the entire slurry 6 is reduced to a viscosity that can be driven by the main stirrer 1.

When the viscosity of the slurry 6 decreases to a certain degree and reaches a certain value, the auxiliary movement device 13 of the auxiliary agitator 8 is activated by a signal from the agitator controller 14, and the agitating blades 12 are automatically returned to their original state. Return to state. At the same time, the moving device 3 of the main stirrer 1 works to rotate the stirring blades 9 at a low speed while gradually lowering them until they return to a predetermined position. Thereafter, the temperature inside the tank 4 is kept constant at 200° C. while stirring using only the main stirrer 1.
When the temperature is stabilized, the on-off valve 17 at the bottom of the tank 4 is opened, the on-off valve 19 is opened, the on-off valve 20 on the slurry supply pipe 18 is closed, and the slurry pump 16 is operated. After the slurry is circulated through the circulation pipe 11, the on-off valve 20 is gradually opened, and the slurry is supplied to the gasifier while adjusting the opening degree of the on-off valve 19. When supplying the slurry to the gasifier, the slurry must be flowed through the circulation pipe 15 to prevent coal particles from adhering to each other and to prevent uneven coal concentration within the tank.

Example The slurry supply tank is a SUS container with an inner diameter of 800 mmφ, a vertical height of 530 mm, and a tapered part height of 360 mm.
It has a taper angle of 40°. On the outer wall of the tank,
A sheathed heater is installed for heating. A main stirrer with a capacity of 1.5KW was installed in the center of the upper part of the tank, and was equipped with a hydraulic cylinder-type moving device that could move it up and down. In addition, two agitators (capacity 0.8KW) similar to the main agitator were installed as auxiliary agitators in the lower taper part of the tank.

The experimental conditions were as follows: A slurry with a coal concentration of 30 Wt% was prepared by mixing coal (particle size 0.105 to 0.42 mm) and petroleum-based vacuum residue oil (asphalt), 260 ml of slurry was filled into a slurry tank, and the slurry was left for about one round. (The stirring blades of the main stirrer were installed in the upper position), and the experiment was conducted with the temperature inside the slurry tank set at 200°C.
As a result, the viscosity of the deposited layer at rest is
The main stirrer did not work at 10,000 cp.

Therefore, when we activated the auxiliary stirrer installed in the taper part to stimulate the deposited layer, the viscosity increased to 1000~
It dropped to 2000cp and the main stirrer was turned manually.
Then, the auxiliary stirrer was returned to its original position, and the main stirrer was gradually lowered while rotating to be placed in its normal position. Slurry viscosity throughout the tank is 180
It dropped to ~200cp and stabilized.

The total time required during this time was about 6 hours. This was because it took about 4 to 5 hours to heat the heater, and it was found that increasing the heater capacity would allow the main stirrer to operate sooner and achieve a steady state.

According to the present invention, it is possible to reduce the influence of sedimentation and accumulation of coal particles in the slurry on the operation of the main agitator, and at the same time, it is possible to operate the main stirrer in a short time even if the tank is left filled with the coal particles for a long time. It also has the effect of preventing adhesion of particles to each other and the formation of areas with uneven coal concentration.

[Brief explanation of drawings]

FIG. 1 is a schematic front view of a stirring device for a mixture of coal and petroleum residue oil of the present invention, and FIG. 2 is a top view of the stirring device of FIG. 1. 1... Main stirrer, 3... Transfer device, 4... Tank, 6... Slurry, 7... Viscosity detector, 8...
Auxiliary stirrer, 13... Auxiliary moving device, 15... Circulation piping.

Claims (1)

[Scope of Claims] 1. A method for stirring a mixture of coal in which particulate coal has settled and accumulated in a tank and petroleum-based vacuum residue oil, comprising: a main stirrer that is vertically movable provided at the top of the tank; Using a tank having two vertically movable auxiliary agitators, the mixture is heated to 200°C or higher and stirred by the auxiliary agitators to reach a viscosity that allows the main agitator to drive, and then the main agitator is stirred. A method for stirring a mixture of coal and petroleum-based vacuum residue oil, characterized by stirring with a machine. 2. A method for stirring a mixture of coal and petroleum-based vacuum residue oil according to claim 1, characterized in that the viscosity of the mixture is detected by a viscosity detector installed in a tank, and the main stirrer is driven based on the detected viscosity. .