Waste heat pre-drying gasification as-fired coal device

Abstract

The utility model discloses a device for pre-drying and gasifying coal as fired by waste heat, which belongs to the technical field of pulverized coal gasification and comprises a heat exchanger. A heat exchanger shell side inlet is connected to a raw coal silo through a coal conveying belt, and a heat exchanger shell side outlet is connected with a pulverized coal spiral conveyor inlet; a heat exchanger tube pass inlet is connected with a desalted water waste boiler steam outlet through a first pipeline, and a heat exchanger tube pass outlet is connected with a normal-pressure hot water storage tank through a second pipeline; an exhaust pipe is further arranged on the heat exchanger shell side. According to the utility model, water outside feed coal can be removed under the condition of utilizing the existing heat source, and the consumption of a gasification section is reduced on the premise of secondary utilization of energy.

Description

Technical Field

[0001] The utility model relates to the technical field of pulverized coal gasification, in particular to a device for pre-drying and gasifying coal entering a furnace using waste heat. Background Art

[0002] In the pulverized coal gasification process, excessive moisture content of the coal entering the furnace may cause the following problems:

[0003] Unstable combustion: High moisture content will absorb heat, lower the temperature in the furnace, increase the ignition point of the coal, make the combustion unstable, and affect the gasification efficiency.

[0004] Increased energy consumption: The evaporation of water requires a lot of heat, which will lead to energy waste and increase production costs.

[0005] Equipment corrosion: Water at high temperatures will generate hydrogen and other corrosive gases, which may corrode gasifiers and other equipment.

[0006] Pipeline blockage: Coal with high moisture content can easily cause pipeline blockage during transportation, affecting production continuity.

[0007] Increased gasifier load: The evaporation of water will increase the gasifier load, which may lead to uneven temperature distribution in the furnace and affect the gasification effect.

[0008] Deterioration in the quality of gasification products: High moisture content will affect the composition and quality of gasification products, possibly resulting in a decrease in the proportion of effective components in the syngas.

[0009] Environmental pollution: The evaporation of water may cause the outlet temperature of the gasifier to decrease, affect the efficiency of the dust removal equipment, and increase dust emissions.

[0010] Safety risks: High moisture content may cause temperature fluctuations in the furnace, increase operating difficulties, and may even cause safety accidents.

[0011] Therefore, in the pulverized coal gasification process, the moisture content of the coal entering the furnace is usually required to be within a certain range to ensure the stability and economy of the gasification process. If the moisture content of the raw coal is too high, it is necessary to reduce the moisture content through pretreatment to ensure the normal operation of the gasifier and gasification efficiency.

[0012] The moisture contained in raw coal is divided into internal water and external water.

[0013] Internal water in raw coal refers to the capillary water adsorbed or contained inside the coal particles and the wetting water present on the surface of the coal particles. Internal water is an inherent part of coal and is related to the physical and chemical structure of coal. Therefore, it cannot be completely removed, but its content can be reduced by drying. The following are several common methods for dehydrating raw coal:

[0014] Natural drying: Pile the coal in a dry and ventilated place to allow the moisture in the coal to evaporate naturally. This method takes a long time and the effect is greatly affected by climatic conditions.

[0015] Artificial drying: using drying equipment, such as drying drums, vibrating fluidized bed dryers, etc., to reduce the moisture content of coal by heating. This method is highly efficient but consumes a lot of energy.

[0016] Hot air drying: Hot air is generated by a hot air furnace and blown over wet coal to accelerate the evaporation of moisture. This method is faster than natural drying but consumes less energy than artificial drying.

[0017] Freeze drying: After freezing the coal, the ice is sublimated into water vapor under vacuum conditions to remove moisture. This method is more effective, but the equipment cost is high.

[0018] Chemical drying: absorb the moisture in the coal by adding chemical desiccants such as calcium chloride, sodium sulfate, etc. This method is simple and easy, but it may affect the quality of the coal.

[0019] Mechanical drying: The water in the coal is squeezed out by mechanical forces such as centrifugal force and pressure. This method is suitable for sticky materials such as clay, but has limited effect on coal.

[0020] External water in raw coal, also known as surface water or free water, refers to the water present on the surface of coal particles and in the pores. This part of water is relatively easy to remove. The presence of external water will affect the combustion performance, transportation efficiency and processing of coal. External water is formed by wetting during the mining, transportation, storage and washing of coal, and can be removed by drying.

[0021] In normal production, reducing the external water content of coal entering the furnace can effectively reduce the consumption of the gasification stage. At present, most coal gasification production enterprises do not dry the coal entering the gasification furnace, or some enterprises use external other heat sources to dry the coal entering the furnace, which increases the additional heat source consumption. Utility Model Content

[0022] The technical problem to be solved by the utility model is to provide a waste heat pre-drying gasification furnace coal device, which can remove water outside the raw coal under the condition of utilizing the existing heat source and reduce the consumption of the gasification section under the premise of secondary utilization of energy.

[0023] In order to solve the above technical problems, the technical solution adopted by the utility model is:

[0024] A waste heat pre-drying and gasifying device for feeding coal into a furnace comprises a heat exchanger; the shell side inlet of the heat exchanger is connected to a raw coal silo through a coal conveying belt, and the shell side outlet of the heat exchanger is connected to the inlet of a pulverized coal screw conveyor; the tube side inlet of the heat exchanger is connected to the steam outlet of a desalted water waste boiler through a first pipeline, and the tube side outlet of the heat exchanger is connected to a normal pressure hot water storage tank through a second pipeline; an exhaust pipe is also arranged on the shell side of the heat exchanger.

[0025] A further improvement of the technical solution of the utility model is that the normal pressure hot water storage tank is connected to the water treatment station through a third pipeline.

[0026] A further improvement of the technical solution of the utility model is that a water delivery pump is arranged on the third pipeline.

[0027] A further improvement of the technical solution of the utility model is that the outlet of the pulverized coal screw conveyor is connected to a coal mill.

[0028] A further improvement of the technical solution of the utility model is that the exhaust pipe is connected to a volatile organic compound treatment system.

[0029] Due to the adoption of the above technical solution, the technical progress achieved by the utility model is:

[0030] 1. The waste heat pre-drying gasification furnace coal device of the utility model dries the raw coal before entering the furnace, thereby increasing the calorific value of the gasified coal gas and reducing the consumption during the gasification process.

[0031] 2. The waste heat pre-drying gasification coal feeding device of the utility model utilizes the existing heat source and does not require an additional heat source, thus greatly reducing the primary investment, and has a simple process, easy operation and good application effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a schematic diagram of the utility model of a waste heat pre-drying gasification furnace coal device;

[0033] Among them, 1. heat exchanger, 2. coal conveyor belt, 3. first pipeline, 4. second pipeline, 5. normal pressure hot water storage tank, 6. exhaust pipe, 7. pulverized coal screw conveyor, 8. third pipeline. DETAILED DESCRIPTION

[0034] The present invention is further described in detail below with reference to the accompanying drawings and embodiments:

[0035] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" ... etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0036] In addition, the terms "first", "second", etc. are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first", "second", etc. may explicitly or implicitly include at least one of the features. In the description of the present utility model, the meaning of "several" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0037] like Figure 1 As shown, a waste heat pre-drying gasification device for feeding coal into a furnace comprises a heat exchanger 1; the shell side inlet of the heat exchanger 1 is connected to the raw coal silo through a coal conveyor belt 2, and the shell side outlet of the heat exchanger 1 is connected to the inlet of a pulverized coal screw conveyor 7; the tube side inlet of the heat exchanger 1 is connected to the steam outlet of a desalted water waste boiler through a first pipeline 3, and the tube side outlet of the heat exchanger 1 is connected to a normal pressure hot water storage tank 5 through a second pipeline 4; an exhaust pipe 6 is also arranged on the shell side of the heat exchanger 1.

[0038] The normal pressure hot water storage tank 5 is connected to the water treatment station via a third pipeline 8, and a water delivery pump is provided on the third pipeline 8;

[0039] The outlet of the pulverized coal screw conveyor 7 is connected to the coal mill;

[0040] The exhaust pipe 6 is connected to a volatile organic compound (VOCs) treatment system.

[0041] Working principle:

[0042] The saturated steam from the steam outlet of the desalted water waste boiler is transported into the shell side of the heat exchanger 1 through a pressure pipeline, and the raw coal coming out from the lower part of the raw coal silo enters the tube side of the heat exchanger 1 through the coal conveyor belt 2. The saturated steam and the raw coal are indirectly heat exchanged in the heat exchanger 1. The condensed water after the heat exchange flows by gravity through the pipeline to the atmospheric hot water storage tank 5 and then is pressurized and transported to the water treatment station by a hot water pump for the next step of treatment; after the raw coal is heated by steam, the water vapor passes through the exhaust pipe 6 to remove the VOCs treatment system, and the raw coal with external water removed enters the coal mill through the pulverized coal screw conveyor 7 directly connected to the heat exchanger 1 for the next step of processing.

[0043] The utility model utilizes the black ash water at about 150°C of the high-pressure flash evaporator in the gasification section to heat the desalted water to generate 0.2MPa, 130°C saturated steam, utilizes the heat contained in this part of the steam to dry the coal entering the furnace, removes the external water of the raw coal, and achieves the purpose of reducing the consumption of the gasification section.

Claims

1. A waste heat pre-drying gasification device for inlet coal, characterized in that: The invention comprises a heat exchanger (1); the shell side inlet of the heat exchanger (1) is connected to the raw coal silo through a coal conveying belt (2), and the shell side outlet of the heat exchanger (1) is connected to the inlet of a pulverized coal screw conveyor (7); the tube side inlet of the heat exchanger (1) is connected to the steam outlet of a desalted water waste boiler through a first pipeline (3), and the tube side outlet of the heat exchanger (1) is connected to a normal pressure hot water storage tank (5) through a second pipeline (4); and an exhaust pipe (6) is also provided on the shell side of the heat exchanger (1).

2. The waste heat pre-drying gasification coal feeding device according to claim 1 is characterized in that: The normal pressure hot water storage tank (5) is connected to the water treatment station via a third pipeline (8).

3. The waste heat pre-drying gasification coal feeding device according to claim 2 is characterized in that: A water delivery pump is provided on the third pipeline (8).

4. The waste heat pre-drying gasification coal feeding device according to claim 1 is characterized in that: The outlet of the pulverized coal screw conveyor (7) is connected to a coal mill.

5. The waste heat pre-drying gasification coal feeding device according to claim 1 is characterized in that: The exhaust pipe (6) is connected to a volatile organic compound treatment system.

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