Method for improving coal quality by utilizing sensible heat of coke

Abstract

The invention discloses a method for improving coal quality by using coke sensible heat, which is characterized in that high-temperature coke with high sensible heat and low-quality coal or high-moisture coal are contacted and mixed according to a reasonable proportion, and the low-quality coal or the high-moisture coal can be dried and pyrolyzed by using the high sensible heat of the high-temperature coke so as to improve the coal quality. And the sensible heat of the high-temperature coke can be effectively utilized, the energy waste is reduced, the external energy input is reduced, the production cost of coal upgrading is reduced, the use amount of cooling water or air for cooling the high-temperature coal can be reduced, and the production cost is further reduced. The upgraded low-rank coal or high-moisture coal can reach the quality of injection coal and high-calorific-value electric coal.

Description

Technical Field

[0001] The present invention relates to the technical field of coal quality improvement, and particularly to a method for improving coal quality by utilizing the sensible heat of coke. Background Art

[0002] Low-rank coals (such as lignite and long-flame coal) and high-moisture coals are difficult to be directly used for blast furnace smelting or power generation due to their high moisture content, low calorific value and poor combustion performance. Generally, external heat sources (energy) need to be introduced for coal quality improvement (such as pyrolysis, drying) to reduce moisture, increase calorific value and improve combustion performance, resulting in high energy consumption and high cost. Coke, as an important raw material for steelmaking, is usually obtained by dry distillation of coal at high temperature. A large amount of high-temperature coke (about 500°C - 1000°C) will be produced during the coke production process. Generally, high-temperature coke needs to be quenched. Coke quenching is mainly divided into wet quenching and dry quenching. However, both the equipment investment and operating cost of dry quenching are higher than those of wet quenching, and dry quenching usually produces harmful substances such as nitrogen oxides, which is easy to cause environmental pollution. Therefore, some manufacturers still use wet quenching. However, wet quenching requires a large amount of cooling water, and quenching high-temperature coke with cooling water will cause the sensible heat of high-temperature coke to be wasted, resulting in waste of water resources and energy. Summary of the Invention

[0003] Therefore, based on the above background, the present invention develops a method for improving coal quality by utilizing the sensible heat of coke, which can effectively utilize the sensible heat of high-temperature coke, reduce water resources and energy waste, and can reduce the production cost of upgrading low-rank coal or high-moisture coal.

[0004] The technical solution provided by the present invention is as follows:

[0005] A method for improving coal quality by utilizing the sensible heat of coke, comprising the following steps:

[0006] 1) Prepare the coal to be upgraded and high-temperature coke in proportion;

[0007] 2) Mix the room-temperature coal to be upgraded with the high-temperature coke and stir;

[0008] 3) After the temperature drops below room temperature, separate the coke from the upgraded coal.

[0009] Preferably, the temperature of the high-temperature coke is 500°C - 1400°C.

[0010] Preferably, the total water content of the coal to be upgraded is 18wt% - 25wt%.

[0011] Preferably, in step 1), the mass ratio of high-temperature coke to the coal to be upgraded is (1 - 5):(5 - 9).

[0012] Preferably, the mass ratio of the high-temperature coke to the coal to be upgraded in step 1) is 1:1.

[0013] Preferably, the coal to be upgraded in step 1) includes at least one of low-rank coal and high-moisture coal.

[0014] Preferably, the low-rank coal includes at least one of lignite and long-flame coal.

[0015] Preferably, in step 2), a mixing drum is used to stir and mix the coal to be upgraded and the high-temperature coke.

[0016] Preferably, the rotation speed of the mixing drum in step 2) is 6 - 10 revolutions per minute.

[0017] Adopting the above technical solutions, the beneficial effects are as follows:

[0018] In the present invention, by contacting and mixing high-temperature coke with high sensible heat and low-quality coal or high-moisture coal in a reasonable proportion, the high sensible heat of the high-temperature coke can be used to dry and pyrolyze the low-quality coal or high-moisture coal, so as to improve its coal quality. It can not only effectively utilize the sensible heat of the high-temperature coke, avoid energy waste, reduce the input of external energy, and reduce the production cost of coal upgrading, but also reduce or even avoid quenching the high-temperature coke with cooling water, avoid waste of water resources, and can reduce the production cost of high-temperature coke.

[0019] The low-rank coal or high-moisture coal upgraded by the present invention can reach the quality of injection coal and high-calorific value power coal. Detailed Embodiments

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art without creative efforts based on the embodiments of the present invention belong to the scope of protection of the present invention.

[0021] The embodiments of the present invention are described in detail below. The examples of the embodiments are shown in the accompanying drawings, in which the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "left", "right", "inner", "outer", "vertical", "circumferential", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the present invention.

[0022] In the description of the present invention, the "first feature" and "second feature" may include one or more of such features. In addition, the terms "first" and "second" are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features.

[0023] The technical solution of the present invention is as follows:

[0024] A method for improving coal quality by utilizing the sensible heat of coke, comprising the following steps:

[0025] 1) Prepare the coal to be upgraded and high-temperature coke in proportion;

[0026] In this step: the temperature of the high-temperature coke is 500°C to 1400°C, preferably 700°C to 1000°C;

[0027] The total moisture content of the coal to be upgraded is 18wt% - 25wt%.

[0028] The mass ratio of high-temperature coke to the coal to be upgraded is (1 - 5):(5 - 9), preferably the mass ratio of high-temperature coke to the coal to be upgraded is 1:1;

[0029] The coal to be upgraded includes at least one of low-rank coal and high-moisture coal.

[0030] The low-rank coal includes at least one of lignite and long-flame coal.

[0031] Specifically, the particle size of the high-temperature coke in this step is 2 - 3 cm, and the particle size of the coal to be upgraded is less than 1 cm.

[0032] 2) Mix the coal to be upgraded and the high-temperature coke and then stir;

[0033] In this step, a mixing drum is used to stir and mix the coal to be upgraded and the high-temperature coke. Specifically, the mixing drum has an exhaust pipe communicating with its cylinder cavity, which is a conventional structure and will not be elaborated here.

[0034] The rotation speed of the mixing drum is 6 - 10 revolutions per minute.

[0035] In specific applications, within 2 minutes of mixing, the mixture can be reduced to below 50°C.

[0036] 3) After the temperature drops to room temperature, separate the coke from the upgraded coal. The room temperature is 25 - 35°C.

[0037] In this step, the coke is separated from the upgraded coal by screening.

[0038] The following examples take lignite and high-temperature coke at 1000 °C discharged from a high-temperature coke oven as examples to improve the quality by adopting the technical solution of the present invention.

[0039] In the following examples, lignite of the same batch was used. The lignite was purchased from TBEA No. 1 Mine. The total moisture of the lignite to be upgraded was detected. Its average total moisture content was 25.1 wt%, the internal moisture content was 1.73 wt%, and the external moisture content was 23.3 wt% (the detection standard for the total moisture content of coal is GB / T 211-2017); the high calorific value of the lignite before upgrading was 6300 kcal / kg, and the low calorific value was 4355 kcal / kg.

[0040] Example 1: A method for improving the quality of coal by using the sensible heat of coke, comprising the following steps:

[0041] 1) Prepare the coal to be upgraded and high-temperature coke in proportion;

[0042] The mass ratio of high-temperature coke to the coal to be upgraded is 1:9;

[0043] Specifically, the particle size of the high-temperature coke in this step is 2-3 cm, and the particle size of the coal to be upgraded is less than 1 cm.

[0044] 2) Mix the coal to be upgraded and high-temperature coke and then stir;

[0045] In this step, a mixing drum is used to stir and mix the coal to be upgraded and high-temperature coke.

[0046] The rotation speed of the mixing drum is 6-10 revolutions per minute.

[0047] 3) After the temperature drops to room temperature, separate the coke from the upgraded coal.

[0048] In this step, the coke and the upgraded coal are separated by screening.

[0049] Example 2: Compared with Example 1, in step 1), the mass ratio of high-temperature coke to the coal to be upgraded is 2:8.

[0050] Example 3: Compared with Example 1, in step 1), the mass ratio of high-temperature coke to the coal to be upgraded is 3:7

[0051] Example 4: Compared with Example 1, in step 1), the mass ratio of high-temperature coke to the coal to be upgraded is 4:6.

[0052] Example 5: Compared with Example 1, in step 1), the mass ratio of high-temperature coke to the coal to be upgraded is 5:5.

[0053] And it has been verified by experiments that when the mass ratio of the high-temperature coke to the coal to be upgraded is greater than 1:1, the high-temperature coke cannot reach coke quenching within 2 minutes and additional cooling water is required.

[0054] Comparative Example 1: In this comparative example, water spraying wet quenching was used to quench high-temperature coke at 1000°C with cooling water.

[0055] The water content and calorific value of the high-temperature coke and the coal to be upgraded in Examples 1 to 5 and their Comparative Example 1 after mixing were detected, and the results are shown in Table 1 (each example was carried out with three parallel experiments, and the results were averaged).

[0056] Table 1: Experimental Results

[0057]

[0058] The present invention and its embodiments have been described above. Such description is not restrictive. What is shown in the drawings is only one of the embodiments of the present invention, and the actual structure is not limited thereto. Generally speaking, if those of ordinary skill in the art are inspired by it and design similar structural modes and embodiments without creative work without departing from the purpose of the present invention, they shall fall within the protection scope of the present invention.

Claims

1. A method for improving coal quality by utilizing sensible heat of coke, characterized in that: The steps include: 1) Prepare the coal to be upgraded and high-temperature coke in proportion; 2) mixing the room temperature coal to be upgraded with the high temperature coke and stirring; 3) After the temperature of the mixed material drops to room temperature, the coke and the upgraded coal can be separated.

2. A method for improving coal quality by utilizing sensible heat of coke according to claim 1, characterized in that: The temperature of the high temperature coke is 500°C to 1400°C.

3. A method for improving coal quality by utilizing sensible heat of coke according to claim 2, characterized in that: The total water content of the coal to be upgraded is 18wt%-25wt%.

4. A method for improving coal quality by utilizing sensible heat of coke according to claim 3, characterized in that: In step 1), the mass ratio of medium-high temperature coke to the coal to be upgraded is (1-5):(5-9).

5. A method for improving coal quality by utilizing sensible heat of coke according to claim 4, characterized in that: Step 1) The mass ratio of medium-high temperature coke to the coal to be upgraded is 1:

1.

6. A method for improving coal quality by utilizing sensible heat of coke according to claim 1, characterized in that: The coal to be upgraded in step 1) includes at least one of low-rank coal and high-moisture coal.

7. A method for improving coal quality by utilizing sensible heat of coke according to claim 6, characterized in that: The low-rank coal includes at least one of lignite and long flame coal.

8. The method for improving coal quality by utilizing sensible heat of coke according to claim 1, characterized in that: In step 2), a mixing drum is used to stir and mix the coal to be upgraded and the high-temperature coke.

9. A method for improving coal quality by utilizing sensible heat of coke according to claim 8, characterized in that: In step 2), the rotating speed of the mixing drum is 6-10 rpm.

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