JPS60123592A - Gasification of coal and coke in coke manufacturing plant - Google Patents

Abstract

PURPOSE:To accomplish coke gasification in high efficiency, easy to take out ash, capable of preventing troubles due to tar, by charging the moving bed of CDQ unit with coke derived from dry distillation of coal in coke oven to perform gasification using gasification agent. CONSTITUTION:Coke oven (dry distillation oven) 1 is charged with low-grade coal, high-volatiles coal, etc., which is then subjected to dry distillation to obtain gas (COG), tar and low-strength coke. Only the resulting coke is fed to dry-type coke-extinguishing unit CDQ2 while in a red-hot state or after tentative cooling, to perform gasification by blowing, from the either upper or lower part of the CDQ through blowers 3, 4, gasification agent such as O2, air, H2O. The sensible heat in the gas generated is recovered by boiler 5, whereas part of the resulting gas is circulated by blower 6 to said CDQ2 for use as cooling gas. EFFECT:Capable of using coke with a wide range of granular sizes.

Description

[Detailed description of the invention] [Technical outline] The present invention gasifies coal and coke in a coke manufacturing plant to produce two gases that can be used as fuel and chemical raw materials.
This invention relates to a method for efficient gasification using a stage gasification method.

[Prior art]

In conventional coke plants, coal is carbonized to mainly obtain coke, tar, and coke carbonization gas. The method of obtaining gas from coal in this way is called carbonization gasification, but since the main purpose is generally to produce coke, carbonization is carried out only under coal blending conditions that yield high-quality coke. Coal carbonized gas (COG) is recovered. Of course, there is no problem with this COG recovery method for the current usage of coke ovens whose main purpose is to produce coke, but when coke ovens are used for the main purpose of gas production, However, there is a problem in that the types of coal that can be used are limited. In other words, under the current method, basically only coal with a blend that can produce coke that can be used in blast furnaces for steelmaking can be used. Many methods of gasifying coal, etc. have been published in the past, as shown in Table 1 below.

These conventional methods generally have the following problems.

1) In the one-stage coal gasification method, the hydrogen in the coal has the same effect as water and has disadvantages such as not being able to be used effectively and the consumption of oxygen to be blown as a gasifying agent becoming high.

2) Tar generated during trench gasification can easily cause equipment trouble.

6) Instead, there is a method of gasifying surplus coke in a coke factory using gas from a generator, but the equipment costs are high, and the calorific value of the gas produced is low at 900 to 1600 u/Nd, resulting in increased costs such as mixing oil etc. Heat countermeasures are being taken.

4) There are many other processes that are still in the research stage, and the practical application of these processes will be difficult due to difficulties in scaling up.

5) Caking coal used as a raw material for steelmaking is generally (
It is difficult to use due to its caking property (particularly in fluidized bed and fixed bed type gasifiers).

In addition to the problems with the conventional technology mentioned above, in the current operating conditions of coke plants, there is a
(Coke Dry Quencher: A device that saves energy by recovering the sensible heat of the red-hot coke discharged from the furnace.The coke is cooled to around 200℃ by heat exchange with an inert gas in a cooling chamber, and then cut into fixed amounts. (After heat exchange, the inert gas heated to 800°C passes through the primary dust box, where the heat is recovered in the boiler, and the circulation blower is used to pump it again to the cooling room.) There are idle machines in the equipment. Therefore, one of the challenges is to utilize it effectively.
It is one. Considering the overall balance of the steelworks, N2
Since N2 and 02 are manufactured from air, if the amount of N2 used increases relatively, surplus 02 will be generated, and it is desirable to use this 02 effectively. Increasing the production of fuel gas to provide energy for steelworks is also an important issue.

[Purpose of the invention]

It is an object of the present invention to solve the problems inherent in the steelworks in addition to the problems of the prior art as described above.

Namely, 1) Reducing the equipment cost of the gasifier (two-stage gasification is possible by simply modifying the existing equipment).

2) Adjustment of gas balance within the steelworks (If surplus 02 is generated, it will be effectively used as a gasification agent to produce gas for fuel, etc.) 6) Effective use of idle CDQ equipment (with some modifications) It can be used as a gasifier, and can be quickly returned to its original state when used as a fire extinguishing equipment.) 4) Effective use of coke powder (gasification of coke with a wide particle size distribution ranging from powder to lumps).

-,) 5) Eliminating tar troubles in gasifiers (remove tar troubles in gasifiers by removing tar in coke ovens) 6) Expanding the types of coal used in coke plants (low-strength coke 7) Expanding the types of coal that can be used in gasifiers (caking coal, which is generally difficult to use in gasifiers, can be easily used in two-stage gasification using a coke oven and CDQ) It can be gasified.) etc.

[Summary of the invention]

The present invention is a method for gasifying coal and cokes in a coke manufacturing plant, which is characterized in that a coke oven and CDQ equipment are used together as a coal gasification device, and the coal is carbonized in a coke oven, Coke carbonization gas, coke, and tar are produced, the resulting coke is charged into a moving bed of CDQ equipment, and the coke is gasified using oxygen or air and water as gasifying agents.

FIG. 1 is a process diagram based on the present invention, and FIG. 2 is an explanatory diagram of CDQ equipment used in the present invention. Figures 1 and 2
In the figure, first, low-cost coal or high-volatile coal is charged into a coke oven (carbonization furnace) 1 and carbonized. This charged coal may be of a nature that can be extruded from the coke oven 1.

Gas (coG), tar, and low-strength coke are generated in the coke oven 1. In the present invention, since tar is removed at this stage, tar trouble can be prevented. The generated coke is left in a red-hot state with N gas, or once cooled, a gas stopper injection device is added and the product is diverted to CDQ.
2 and gasified. gasifying agent 02 or air,
H2O (steam) is blown into the CDQ from the upper or lower part of the CDQ through the pro- cesses 6 and 4. The sensible heat of the generated gas is recovered by the sensible heat recovery boiler 5 of the CDQ, and a part of the recovered gas is circulated to the CDQ by the blower B as a cooling gas, and the rest has a calorific value of 1000 to 250.
Generates gas used as gas fuel for 017/N-.

The gasified residue (ash) of CDQ is cooled with gas and then discharged. Ash content is easily extracted using a moving bed type CDQ.

In CDQ, coke reacts as a moving layer, so coke with a wide range of particle size distributions from powder to lumps can be used, and coke can still be gasified in two stages.

〔Example〕

Next, an example will be described in comparison with a conventional method.

Since the present invention employs two-stage gasification using a coke oven and CDQ, the hydrogen in the coal is effectively used, and the gas generated from the coke oven is second-stage gasification compared to the gas produced in the first-stage gasification.
As shown in the clothes (there are many CHt etc. and the high strength T collie is cut out 4
゛71, Table 2 Comparison of gas calorific value □/N++/ No, coking coal is useless, and the C0ED-COGAS method (d
Caking coal is used, and for this purpose a multi-stage carbonization fluidized bed (6
~4 steps).

In the present invention, since a coke oven is used in the carbonization step, it is extremely easy to use coking coal. Incidentally, the actual coal blending results for current coke ovens are as shown in Table 3 below, and with such blending it is extremely difficult to gasify using conventional methods.

Table 2: Coal blending results (coke oven) This is because a reactor like a moving bed of species called CDQ is used. In the conventional method using a fluidized bed, in order to fluidize the coke particles, it is necessary to adjust the particle size distribution of the coke, and it is impossible to produce coke particles in the form of lumps. Current coke ovens produce coke with an average particle size of approximately 50m+n, and it is extremely difficult to gasify such large lumps using conventional methods. On the other hand, powdered coke can be easily gasified in water droplets7, but cannot be used in the conventional fluidized bed method because the particle size is too fine and the amount of coke increases.

Next, when the blended coal shown in Table 4 is carbonized, the strength of the coke produced is too low to be used in a blast furnace.
If this is gasified at CDQ, it can be used effectively and the types of coal used at coke plants can be expanded.

Table 4 Coal blending example to obtain low-strength coke (Current coke strength target is DI Ding-94, 8) If the two-stage gasification method is used (coke oven CDQ), if it can be extruded from the coke oven, All kinds of coal can now be used effectively, and the second-stage gasifier produces 75 gases as shown in Table 5! Being ignored.

The ash remaining after gasification of CDQ can be easily extracted because the moving bed type CDQ is used, and there is little gear overflow of ash (which is significantly superior to the conventional method).

〔Effect of the invention〕

The present invention has/does not have the following effects.

1) Sensible heat recovery from gas generated from CDQ can be easily performed, and CDQ can also be used as a thermal energy generating furnace.

2) If there is surplus 02, the 02 can be used effectively to drain the fuel gas, and the gas balance of the factory A can be adjusted.

6) By slightly modifying idle CDQ, it can be used effectively as a gasifier, and if necessary, it can be quickly returned to the original CDQ. 1, 4) Equipment costs are lower than with conventional gasification methods. is cheap.

5) The types of coal used in coke plants can be expanded.

6) Tar trouble during gasification is resolved.

The present invention has many effects and can be called a useful method.

[Brief explanation of the drawing]

Figure 1 is a process diagram of the present invention, and Figure 2 is a process diagram of the present invention.
This is an explanatory diagram of the DQ equipment. 1: Coke oven, 2: CDQ15: Sensible heat recovery column (Ilar

Claims (1)

[Claims] Coal is carbonized in a coke oven to produce coke carbonization gas, coke and tar, and the resulting coke is subjected to CDQ (
A method for gasifying coal and coke, which comprises charging the coke into a moving bed of a coke dry extinguishing system and gasifying the coke using oxygen or air and water as gasifying agents.