Device for treating gasified fine slag through circulating fluidized bed oxygen-enriched combustion

Abstract

The utility model belongs to the technical field of coal gasification solid waste treatment, and particularly relates to a device for treating gasified fine slag by adopting circulating fluidized bed oxygen-enriched combustion, which comprises a gasifier, a carbon black washing tower, a flash tower, a settling tank, a filter press and a circulating fluidized bed boiler, gasification black water outlets of the gasification furnace and the carbon black washing tower are sequentially connected with a flash tower, a settling tank and a filter press, a fine slag outlet of the filter press is connected with a circulating fluidized bed boiler, a secondary air opening is annularly formed in the lower portion of a hearth of the circulating fluidized bed boiler, and a primary air pipe at the bottom of the hearth of the circulating fluidized bed boiler is connected with an oxygen-enriched mixer. And the oxygen-enriched mixer is connected with the oxygen storage tank through an oxygen delivery pipe. According to the utility model, the harmless and resource utilization of the gasified fine slag is realized, the resource utilization efficiency of coal is improved, meanwhile, solid wastes generated in the gasification process are treated, and the energy-saving and environment-friendly significance is realized.

Description

Technical Field

[0001] This utility model belongs to the field of coal gasification solid waste treatment technology, and specifically relates to a device for treating gasification fine slag using circulating fluidized bed oxygen-enriched combustion. Background Technology

[0002] Coal gasification is mainly divided into pulverized coal gasification and coal-water slurry gasification. Whether it's pulverized coal or coal-water slurry gasification, the formation process and mechanism of ash and slag are basically the same. During gasification, two types of carbonaceous solid waste are produced: coarse gasification slag and fine gasification slag. Under high temperature and pressure inside the furnace, the coal undergoes rapid pyrolysis, partial combustion, and gasification. During this process, some unreacted carbon is discharged along with the ash and syngas. Coarse gasification slag consists of ash and a small amount of unreacted carbon from the coal, which is then melted, quenched, and solidified before being discharged from the bottom of the gasifier. Its carbon content is generally no higher than 15%, and its high ash content and low calorific value render it unsuitable for resource utilization. Fine gasification slag is formed from the black water discharged from the carbon washing tower, which is then dehydrated through sedimentation and a vacuum filter press, carried by the syngas with some unreacted carbon and ash. After gasification and filtration, the fine slag still contains 30-35% water. The dry base material contains more than 40% fixed carbon and a small amount of volatile matter. It has high calorific value, but the loss on ignition of residual carbon is usually more than 40%, so it cannot be directly used in the cement or concrete industry.

[0003] The fine slag from fluidized bed gasification has the following three main characteristics:

[0004] (1) The fine residue after mechanical dewatering has a strong water-holding capacity and a high moisture content, Q net,ad ≈8.37 MJ / kg, gasification fine residue Q with 30% water content net,ar ≈6.1 MJ / kg;

[0005] (2) Gasification fine slag is the product of gasification at high temperature and high pressure of 1200℃~1300℃. It has extremely low volatile content, poor combustion characteristics, and is difficult to burn directly alone.

[0006] (3) The average particle size of the gasification slag is 30μm. If it is piled up for a long time, it will drift in water or be blown away by the wind, which will easily cause environmental pollution.

[0007] Water-containing gasification slag is generally treated as solid waste and disposed of by landfill, which not only causes serious waste of resources, but also easily leads to soil and groundwater pollution if not handled properly. Summary of the Invention

[0008] The technical problem to be solved by this utility model is to provide a device for treating gasified fine slag by oxygen-enriched combustion in a circulating fluidized bed, so as to achieve the harmlessness and resource utilization of gasified fine slag.

[0009] To achieve the above objectives, the present invention adopts the following technical solution:

[0010] An apparatus for treating gasified fine slag using oxygen-enriched combustion in a circulating fluidized bed includes a gasifier, a carbon black scrubbing tower, a flash evaporator, a settling tank, a filter press, and a circulating fluidized bed boiler. The gasified black water outlets of the gasifier and the carbon black scrubbing tower are sequentially connected to the flash evaporator, the settling tank, and the filter press. The fine slag outlet of the filter press is connected to the circulating fluidized bed boiler. Secondary air inlets are arranged around the lower part of the circulating fluidized bed boiler furnace. An oxygen-enriched mixer is connected to the primary air duct at the bottom of the circulating fluidized bed boiler furnace. The oxygen-enriched mixer is connected to an oxygen storage tank through an oxygen supply pipe.

[0011] The secondary air vents are installed in one or more layers.

[0012] The circulating fluidized bed boiler furnace is equipped with a steam drum at the top.

[0013] The sidewall of the circulating fluidized bed boiler furnace is a water-cooled wall, which is connected to the steam drum at the top of the circulating fluidized bed boiler furnace.

[0014] A regulating valve is connected to the oxygen delivery pipe.

[0015] Compared with existing technologies, the beneficial effects of this utility model are:

[0016] This invention enables the harmless and resource-based utilization of gasification slag, improves the resource utilization efficiency of coal, and treats the solid waste generated during the gasification process, thus having energy-saving and environmental protection significance.

[0017] A circulating fluidized bed boiler is used to process the water-containing gasified fine slag after pressure filtration. In an oxygen-rich environment, the furnace temperature is increased, causing the residual char in the gasified fine slag to burn completely. Simultaneously, the combustion of the gasified fine slag within the circulating fluidized bed boiler generates a large amount of heat, which converts the water in the water-cooled walls into steam, which is then piped out. Part of the fine slag forms fly ash and is discharged with the flue gas, while another part forms bottom ash and is discharged from the bottom ash discharge port of the circulating fluidized bed boiler for use as building materials. This not only achieves efficient energy utilization but also saves production costs. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of this utility model.

[0019] In the diagram: 1. Gasifier; 2. Carbon black scrubbing tower; 3. Flash evaporator; 4. Settling tank; 5. Filter press; 6. Circulating fluidized bed boiler; 7. Secondary air outlet; 8. Primary air duct; 9. Oxygen-enriched mixer; 10. Oxygen supply pipe; 11. Oxygen storage tank; 12. Steam drum; 13. Regulating valve. Detailed Implementation

[0020] In the description of this utility model, it should be understood that the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0021] Unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0022] like Figure 1 A device for treating gasified fine slag using oxygen-enriched combustion in a circulating fluidized bed includes a gasifier 1, a carbon black scrubbing tower 2, a flash evaporator 3, a settling tank 4, a filter press 5, and a circulating fluidized bed boiler 6. The gasified black water outlets of the gasifier 1 and the carbon black scrubbing tower 2 are sequentially connected to the flash evaporator 3, the settling tank 4, and the filter press 5. The fine slag outlet of the filter press 5 is connected to the circulating fluidized bed boiler 6. The circulating fluidized bed boiler 6 includes a furnace and a cyclone separator. A secondary air inlet 7 is arranged around the lower part of the furnace of the circulating fluidized bed boiler 6. An oxygen-enriched mixer 9 is connected to the primary air duct 8 at the bottom of the furnace of the circulating fluidized bed boiler 6. The oxygen-enriched mixer 9 is connected to an oxygen storage tank 11 through an oxygen supply pipe 10.

[0023] The secondary air vent 7 is installed in one or more layers.

[0024] The circulating fluidized bed boiler 6 has a steam drum 12 at the top of its furnace.

[0025] The sidewall of the furnace of the circulating fluidized bed boiler 6 is a water-cooled wall, which is connected to the steam drum 12 at the top of the furnace of the circulating fluidized bed boiler 6.

[0026] A regulating valve 13 is connected to the oxygen delivery pipe 10.

[0027] The oxygen storage tank 11 contains pure oxygen.

[0028] Work process:

[0029] The gasified black water is filtered through flash distillation tower 3, settling tank 4, and filter press 5 to obtain gasified fine slag with a moisture content of 30%–35%. This slag is then sent to the furnace of a circulating fluidized bed boiler. The primary air is regulated to an oxygen content of 35% by an oxygen-enriched mixer. The fine slag combines with the oxygen-enriched primary air to undergo a combustion reaction, reaching an adiabatic combustion temperature of over 1735℃. The combustion material rises to the secondary air zone, where it supplements the air needed for fuel combustion and enhances the disturbance of the material within the furnace. The material circulates repeatedly within the circulating fluidized bed boiler until the residual char in the gasified fine slag is completely burned. This process generates a large amount of heat, which is absorbed by the water-cooled walls to ultimately produce steam and high-temperature flue gas. The steam is sent out for heating, while a portion of the fine slag forms fly ash and is discharged with the flue gas, and another portion forms bottom ash and is discharged from the bottom ash discharge port of the circulating fluidized bed boiler for use as building materials.

[0030] To make the objectives, technical solutions, and technical effects of this utility model clearer, the technical solutions in the embodiments of this utility model are now described clearly and completely. However, the embodiments described below are only some embodiments of this utility model, not all embodiments. All other embodiments obtained by those skilled in the art in conjunction with the embodiments of this utility model without creative effort are within the scope of protection of this utility model.

[0031] Example 1:

[0032] An apparatus for treating gasified fine slag using oxygen-enriched combustion in a circulating fluidized bed includes a gasifier 1, a carbon black scrubbing tower 2, a flash evaporator 3, a settling tank 4, a filter press 5, and a circulating fluidized bed boiler 6. The gasified black water outlets of the gasifier 1 and the carbon black scrubbing tower 2 are sequentially connected to the flash evaporator 3, the settling tank 4, and the filter press 5. The fine slag outlet of the filter press 5 is connected to the circulating fluidized bed boiler 6. Secondary air inlets 7 are arranged in a ring around the lower part of the furnace of the circulating fluidized bed boiler 6, with each layer of secondary air inlets 7 arranged in a single layer. A steam drum 12 is located at the top of the furnace of the circulating fluidized bed boiler 6. The side walls of the furnace of the circulating fluidized bed boiler 6 are water-cooled walls, which are connected to the steam drum 12.

[0033] An oxygen-enriched mixer 9 is connected to the primary air duct 8 at the bottom of the furnace of the circulating fluidized bed boiler 6. The oxygen-enriched mixer 9 is connected to the oxygen storage tank 11 via an oxygen supply pipe 10. A regulating valve 13 is connected to the oxygen supply pipe 10. The oxygen storage tank 11 contains pure oxygen.

[0034] Example 2:

[0035] An apparatus for treating gasified fine slag using oxygen-enriched combustion in a circulating fluidized bed includes a gasifier 1, a carbon black scrubbing tower 2, a flash evaporator 3, a settling tank 4, a filter press 5, and a circulating fluidized bed boiler 6. The gasified black water outlets of the gasifier 1 and the carbon black scrubbing tower 2 are sequentially connected to the flash evaporator 3, the settling tank 4, and the filter press 5. The fine slag outlet of the filter press 5 is connected to the circulating fluidized bed boiler 6. The circulating fluidized bed boiler 6 includes a furnace and a cyclone separator. Secondary air inlets 7 are arranged in a two-layer ring around the lower part of the furnace of the circulating fluidized bed boiler 6. A steam drum 12 is located at the top of the furnace of the circulating fluidized bed boiler 6. The side walls of the furnace of the circulating fluidized bed boiler 6 are water-cooled walls, which are connected to the steam drum 12.

[0036] An oxygen-enriched mixer 9 is connected to the primary air duct 8 at the bottom of the furnace of the circulating fluidized bed boiler 6. The oxygen-enriched mixer 9 is connected to the oxygen storage tank 11 via an oxygen supply pipe 10. A regulating valve 13 is connected to the oxygen supply pipe 10. The oxygen storage tank 11 contains pure oxygen.

[0037] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and basic spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A device for treating gasified fine slag using circulating fluidized bed oxygen-enriched combustion, characterized in that, The system includes a gasifier, a carbon black scrubbing tower, a flash evaporator, a settling tank, a filter press, and a circulating fluidized bed boiler. The gasified black water outlets of the gasifier and the carbon black scrubbing tower are sequentially connected to the flash evaporator, the settling tank, and the filter press. The fine slag outlet of the filter press is connected to the circulating fluidized bed boiler. The lower part of the circulating fluidized bed boiler furnace is equipped with secondary air inlets. An oxygen-enriched mixer is connected to the primary air duct at the bottom of the circulating fluidized bed boiler furnace. The oxygen-enriched mixer is connected to the oxygen storage tank through an oxygen supply pipe.

2. The apparatus for treating gasified fine slag using circulating fluidized bed oxygen-enriched combustion according to claim 1, characterized in that, The secondary air vents are installed in one or more layers.

3. The apparatus for treating gasified fine slag using circulating fluidized bed oxygen-enriched combustion according to claim 1, characterized in that, The circulating fluidized bed boiler furnace is equipped with a steam drum at the top.

4. The apparatus for treating gasified fine slag using circulating fluidized bed oxygen-enriched combustion according to claim 1, characterized in that, The sidewall of the circulating fluidized bed boiler furnace is a water-cooled wall, which is connected to the steam drum at the top of the circulating fluidized bed boiler furnace.

5. The apparatus for treating gasified fine slag using circulating fluidized bed oxygen-enriched combustion according to claim 1, characterized in that, A regulating valve is connected to the oxygen delivery pipe.

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