Vertical furnace coil type coke quenching and waste heat recovery system and method

Abstract

The invention relates to a coiled tube type coke quenching and waste heat recovery system and method for a vertical furnace. The system comprises the vertical furnace, a coiled tube coke quenching device, a steam pocket and a forced circulation pump, the vertical furnace is composed of a vertical furnace carbonization chamber, a star-shaped discharge valve and a plurality of coke quenching channels, coil coke quenching devices are arranged on the peripheries of the coke quenching channels in a one-to-one correspondence mode, and the coil coke quenching devices are connected with the steam pocket through circulating medium pipelines; the coil pipe coke quenching device is composed of multiple layers of coil pipes arranged in the height direction, and the pipe diameter of the upper-layer coil pipe is larger than that of the lower-layer coil pipe. By adopting the collaborative design of layered coil heat exchange and steam pocket, the efficient unification of coke quenching and waste heat recovery is realized, the problems of non-uniform heat exchange, incomplete red coke cooling and the like in the existing vertical furnace coke quenching are solved, the waste heat recovery efficiency is improved, the gradient utilization of red coke sensible heat is realized, the equipment investment is reduced, and the wastewater pollution is avoided.

Description

Technical Field

[0001] This invention relates to the field of coking technology, and in particular to a vertical furnace coil quenching and waste heat recovery system and method. Background Technology

[0002] The vertical furnace is a classic furnace type that uses dry quenching technology to produce red coke. Its core process is that the coal is continuously carbonized in a vertical carbonization chamber, and the produced hot red coke is sealed and cooled at the bottom of the furnace, achieving the dual purpose of energy recovery and environmental protection.

[0003] In the process of producing red coke in a vertical furnace (temperatures typically between 500 and 800°C), coke quenching is a crucial step, but existing coke quenching technologies have the following drawbacks: 1. Wet quenching: Cold water is sprayed directly. Although the equipment is simple, it consumes a lot of water (0.5 to 1.0 t of water per ton of red coke), and the sensible heat of red coke (about 1.4 to 1.6 GJ / t) is completely wasted. It is also easy to generate phenol-containing wastewater pollution. 2. Steam quenching: This involves introducing steam into the quenching box to quench the coke. This method consumes a large amount of steam and it is easy for the steam to react with the coke. There is no sensible heat recovery. 3. Cooling wall quenching: Circulating water is introduced into the cooling wall to quench the coke. There is no heat recovery, and it is difficult to adapt to the temperature gradient of the red coke from top to bottom (the upper layer of red coke is above 800℃, and the lower layer of red coke is 300-500℃), which can easily lead to problems such as "red coke discharge". Summary of the Invention

[0004] This invention provides a vertical furnace coil-type coke quenching and waste heat recovery system and method. It adopts a synergistic design of "layered coil heat exchange + steam drum" to achieve efficient and unified coke quenching and waste heat recovery. It solves the problems of uneven heat exchange and incomplete cooling of red coke in existing vertical furnace coke quenching, improves waste heat recovery efficiency, realizes the cascade utilization of the sensible heat of red coke, reduces equipment investment, and avoids wastewater pollution.

[0005] To achieve the above objectives, the present invention employs the following technical solution: A vertical furnace coil quenching and waste heat recovery system includes a vertical furnace, a coil quenching device, a steam drum, and a forced circulation pump. The vertical furnace consists of a carbonization chamber, a rotary valve, and multiple quenching channels. The red coke outlet at the bottom of the carbonization chamber is connected to the red coke inlet at the top of the multiple quenching channels via the rotary valve. The bottom of each quenching channel has a coke outlet. Coil quenching devices are correspondingly installed around each quenching channel. The coil quenching devices are connected to the steam drum via a circulating medium pipeline, and a forced circulation pump is installed on the circulating medium pipeline. The steam drum has a water inlet connected to a water supply pipeline and a steam outlet connected to a steam pipeline. The coil quenching device consists of multiple layers of coils arranged along the height, with the diameter of the upper coil being larger than that of the lower coil.

[0006] The multi-layer coil consists of 3 to 5 spiral coils; the top 2 to 3 spiral coils are the upper coils, with a diameter of ø50 to ø80 mm, and the bottom 2 to 3 spiral coils are the lower coils, with a diameter of ø30 to ø50 mm.

[0007] Each layer of spiral coil has an independent medium inlet and medium outlet, and the spiral coils of each layer are connected in parallel to the circulating medium pipeline.

[0008] The upper coil is made of 310S heat-resistant steel, and the lower coil is made of 304 stainless steel.

[0009] The coke quenching channel is made of heat-resistant steel pipe, with a diameter of 0.5 to 1 m and a height of 3 to 5 m; a coke discharge valve and a temperature detection device are installed at the coke outlet at the bottom of the coke quenching channel.

[0010] A vertical furnace coil-type quenching and waste heat recovery system further includes a quenching temperature control system; the quenching temperature control system consists of red coke temperature sensors located between each layer of spiral coils, inlet pressure sensors and inlet medium temperature sensors located at the medium inlet of each layer of spiral coils, outlet pressure sensors and outlet medium temperature sensors located at the medium outlet of each layer of spiral coils, and a PLC controller; the PLC controller is also connected to the control terminal of a forced circulation pump.

[0011] A vertical furnace coil-type coke quenching and waste heat recovery system further includes a demineralized water tank, a deaerator pump, a deaerator, a feed water pump, and a steam distribution cylinder; the demineralized water tank is connected to the inlet of the deaerator through a demineralized water pipeline, the outlet of the deaerator is connected to the steam drum through a water supply pipeline, and a feed water pump is installed on the water supply pipeline; the steam drum is connected to the steam inlet of the steam distribution cylinder through a steam pipeline, and the steam outlet of the steam distribution cylinder is connected to the steam inlet of the deaerator and the external steam pipeline respectively.

[0012] The flow rate of the forced circulation pump is 50-100 m³ / h. 3 / h.

[0013] A method for coke quenching and waste heat recovery in a vertical furnace with coils includes the following steps: (1) The coal is continuously carbonized in the carbonization chamber of the vertical furnace. The red coke at 500-800℃ is continuously and uniformly discharged into multiple quenching channels through the star-shaped discharge valve and moves slowly from top to bottom. The residence time of the red coke in the quenching channel is 60-150 minutes. (2) The demineralized water in the steam drum enters each layer of spiral coil of the coil quenching device through the circulating medium pipeline. After exchanging heat with the red coke, the temperature rises and then steam is generated through the steam drum. The steam is sent to the steam distribution cylinder, and part of the steam is sent to the deaerator to preheat the demineralized water extracted from the demineralized water tank to 100-120°C. The preheated demineralized water is used as the circulating medium and is supplied to the circulating medium pipeline through the steam drum. (3) During the descent of the red coke in the quenching channel, it first exchanges heat with the circulating medium in the upper coil and cools down to 300-500℃ before exchanging heat with the circulating medium in the lower coil. The flow rate of the circulating medium in each spiral coil is adjusted by the quenching temperature control system to control the cooling rate of the red coke to 8-10℃ / min. (4) The high-temperature steam-water mixture with a temperature of 400-450°C after heat exchange with the red coke in the coil quenching device is sent into the steam drum to generate saturated steam of 0.8-1.2MPa. The saturated steam is directly sent out for use; or the saturated steam is sent back into the coil quenching device as a circulating medium to exchange heat with the red coke, and superheated steam is generated through the steam drum and sent out for use. (5) When the temperature detection device at the bottom of the coke outlet of the quenching channel detects that the red coke temperature has dropped below 150°C, the coke is discharged through the coke discharge valve.

[0014] Compared with the prior art, the beneficial effects of the present invention are: (1) Good heat exchange uniformity: The layered coil quenching device is adapted to the temperature gradient of the red coke, and the cooling rate of the red coke is stable at 5-8℃ / min, effectively avoiding the discharge of red coke.

[0015] (2) High waste heat recovery rate: The waste heat recovery efficiency reaches 82% to 88%, and each ton of red coke can generate 0.3 to 0.4t of 0.8 to 1.0MPa saturated steam, saving 12,000 to 15,000 tons of standard coal per year (based on a coke production capacity of one million tons).

[0016] (3) Excellent economic performance: Equipment investment is reduced by more than 35% compared with direct steam quenching, there is no wastewater discharge, and water consumption is only 5% of that of wet quenching.

[0017] (4) Good operational stability: The “closed-loop + PLC temperature control” control method can achieve fully automatic operation with a failure rate of less than 3%. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the vertical furnace coil quenching and waste heat recovery system described in this invention.

[0019] In the diagram: 1. Vertical furnace carbonization chamber; 2. Rotary rotary valve; 3. Coil quenching device; 4. Forced circulation pump; 5. Steam drum; 6. Steam distributor; 7. Feedwater pump; 8. Deaerator; 9. Deaerated water pump; 10. Demineralized water tank. Detailed Implementation

[0020] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings: like Figure 1 As shown, the vertical furnace coil quenching and waste heat recovery system of the present invention includes a vertical furnace, a coil quenching device 3, a steam drum 5, and a forced circulation pump 4. The vertical furnace consists of a vertical furnace carbonization chamber 1, a star-shaped discharge valve 2, and multiple quenching channels. The red coke outlet at the bottom of the vertical furnace carbonization chamber 1 is connected to the red coke inlet at the top of multiple quenching channels through the star-shaped discharge valve 2. The bottom of the quenching channels is provided with a coke outlet. Coil quenching devices 3 are provided one-to-one around the quenching channels. The coil quenching devices 3 are connected to the steam drum 5 through a circulating medium pipeline. The forced circulation pump 4 is provided on the circulating medium pipeline. The steam drum 5 is provided with a water inlet connected to a water supply pipeline and a steam outlet connected to a steam pipeline. The coil quenching device 3 consists of multiple layers of coils arranged along the height, and the diameter of the upper coil is larger than that of the lower coil.

[0021] The multi-layer coil consists of 3 to 5 spiral coils; the top 2 to 3 spiral coils are the upper coils, with a diameter of ø50 to ø80 mm, and the bottom 2 to 3 spiral coils are the lower coils, with a diameter of ø30 to ø50 mm.

[0022] Each layer of spiral coil has an independent medium inlet and medium outlet, and the spiral coils of each layer are connected in parallel to the circulating medium pipeline.

[0023] The upper coil is made of 310S heat-resistant steel, and the lower coil is made of 304 stainless steel.

[0024] The coke quenching channel is made of heat-resistant steel pipe, with a diameter of 0.5 to 1 m and a height of 3 to 5 m; a coke discharge valve and a temperature detection device are installed at the coke outlet at the bottom of the coke quenching channel.

[0025] The vertical furnace coil-type quenching and waste heat recovery system of the present invention further includes a quenching temperature control system; the quenching temperature control system consists of a red coke temperature sensor installed between each layer of spiral coils, an inlet pressure sensor and an inlet medium temperature sensor installed at the medium inlet of each layer of spiral coils, an outlet pressure sensor and an outlet medium temperature sensor installed at the medium outlet of each layer of spiral coils, and a PLC controller; the PLC controller is also connected to the control terminal of the forced circulation pump 4.

[0026] The vertical furnace coil quenching and waste heat recovery system of the present invention further includes a demineralized water tank 10, a deaerator water pump 9, a deaerator 8, a feed water pump 7, and a steam distribution cylinder 6; the demineralized water tank 10 is connected to the inlet of the deaerator 8 through a demineralized water pipeline, the outlet of the deaerator 8 is connected to the steam drum 5 through a water supply pipeline, and the water supply pipeline is equipped with a feed water pump 7; the steam drum 5 is connected to the steam inlet of the steam distribution cylinder 6 through a steam pipeline, and the steam outlet of the steam distribution cylinder 6 is connected to the steam inlet of the deaerator 8 and the external steam pipeline respectively.

[0027] The flow rate of the forced circulation pump 4 is 50-100 m³ / h. 3 / h.

[0028] The present invention discloses a vertical furnace coil-type coke quenching and waste heat recovery method, comprising the following processes: (1) The coal is continuously carbonized in the carbonization chamber 1 of the vertical furnace. The red coke at 500-800℃ is continuously and uniformly discharged into multiple quenching channels through the star-shaped discharge valve 2 and moves slowly from top to bottom. The residence time of the red coke in the quenching channel is 60-150 minutes. (2) The demineralized water in the steam drum 5 enters each layer of spiral coil of the coil quenching device 3 through the circulating medium pipeline, and is heated after exchanging heat with the red coke. Then, it generates steam through the steam drum 5. The steam is sent to the steam distribution cylinder 6, and a part of the steam is sent to the deaerator 8 to preheat the demineralized water extracted from the demineralized water tank 10 to 100-120°C. The preheated demineralized water is used as the circulating medium and is supplied to the circulating medium pipeline through the steam drum 5. (3) During the descent of the red coke in the quenching channel, it first exchanges heat with the circulating medium in the upper coil and cools down to 300-500℃ before exchanging heat with the circulating medium in the lower coil. The flow rate of the circulating medium in each spiral coil is adjusted by the quenching temperature control system to control the cooling rate of the red coke to 8-10℃ / min. (4) The high-temperature steam-water mixture with a temperature of 400-450°C after heat exchange with the red coke in the coil quenching device 3 is sent into the steam drum 5 to generate saturated steam of 0.8-1.2MPa. The saturated steam is directly sent out for use; or the saturated steam is sent back into the coil quenching device 3 as a circulating medium to exchange heat with the red coke, and superheated steam is generated through the steam drum 5 and sent out for use. (5) When the temperature detection device at the bottom of the coke outlet of the quenching channel detects that the red coke temperature has dropped below 150°C, the coke is discharged through the coke discharge valve.

[0029] The present invention discloses a vertical furnace coil-type coke quenching and waste heat recovery system. Based on a core structure of "vertical furnace + layered coil + cooling medium circulation," it utilizes demineralized water as the circulating medium for heat exchange and coke quenching, and uses an external steam drum 5 to produce steam, achieving cooling of red-hot coke and cascade recovery of waste heat. The main parameters and functions of each component are as follows: 1. Vertical Furnace: Preferably, a vertical furnace with a square cross-section and a multi-chamber structure is used for the carbonization chamber 1. Preferred external parameters are: length 3-5m, width 0.3-0.8m, and height 8-12m. The bottom of the carbonization chamber 1 is equipped with a sealed discharge port (preferably a star-shaped discharge valve 2), and the bottom of the quenching channel is equipped with a coke discharge valve and a temperature detection device. The red coke discharge rate is controlled at 10-15t / h.

[0030] 2. Coil Quenching Device 3: Composed of multiple layers of coils, preferably 3-5 layers of spiral coils. The upper layer (on the red coke inlet side) uses large-diameter high-temperature resistant coils (diameter ø50-ø80mm, preferably 310S heat-resistant steel) for rapid heat exchange with the high-temperature red coke. The lower layer uses small-diameter coils (diameter ø30-ø50mm, preferably 304 stainless steel) for precise temperature control in the low-temperature section. Each layer of spiral coils has an independent medium inlet and outlet, connected in parallel to the circulating medium pipeline. 3. Cooling medium circulation system: Consists of a forced circulation pump 4 (preferably with a flow rate of 50-100 m³ / h). 3 It consists of a steam drum 5 and a circulating medium pipeline, etc.; it uses demineralized water as the circulating medium to cool the red coke and generate saturated steam or superheated steam for power generation or industrial use.

[0031] 4. Coke quenching temperature control system: The red coke temperature is detected by red coke temperature sensors located at each layer of spiral coil. The circulating medium condition and heat exchange effect are monitored in real time by inlet pressure sensors, outlet pressure sensors, inlet medium temperature sensors and outlet medium temperature sensors located on each layer of spiral coil. The flow rate of the forced circulation pump 4 is controlled by the PLC controller to keep the red coke cooling rate at 5-8℃ / min.

[0032] To more intuitively illustrate the present invention, the embodiments of the present invention will be further described in conjunction with the examples. The following examples are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any technical solutions that can be obviously obtained by those skilled in the art within the scope of the technology disclosed in the present invention, including simple variations or equivalent substitutions, are all within the scope of protection of the present invention.

[0033]

Example

[0034] 2. Coil Quenching Unit 3: Each coil quenching unit 3 has 4 layers of spiral coils. The first and second layers of spiral coils are the upper layers, with a diameter of ø65mm; the third and fourth layers of spiral coils are the lower layers, with a diameter of ø40mm; the spacing between the coil quenching units 3 is 200mm, and the total heat exchange area is 800m². 2 .

[0035] 3. Cooling medium circulation system: Demineralized water is used as the cooling medium, and the flow rate of the forced circulation pump 4 is 75 m³ / h. 3 / h, the steam drum pressure is 1.0MPa.

[0036] 4. System operating parameters: Red coke feed rate: 12 t / h; residence time in coil quenching unit 3: 120 min; coke inlet temperature in coil quenching unit 3: 800℃; coke outlet temperature: 150℃. Circulating medium inlet temperature: 120℃; outlet temperature: 420℃. Steam parameters produced by steam drum 5: pressure 1.0 MPa, temperature 184℃, steam output 4.5 t / h (corresponding to 0.375 t steam per ton of red coke).

[0037] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A vertical furnace coil-type coke quenching and waste heat recovery system, characterized in that, It includes a vertical furnace, a coil quenching device, a steam drum, and a forced circulation pump; the vertical furnace consists of a vertical furnace carbonization chamber, a rotary valve, and multiple quenching channels. The red coke outlet at the bottom of the vertical furnace carbonization chamber is connected to the red coke inlet at the top of multiple quenching channels through the rotary valve. The bottom of the quenching channels is provided with a coke outlet. The outer periphery of the quenching channel is equipped with coil quenching devices, which are connected to the steam drum through a circulating medium pipeline. A forced circulation pump is installed on the circulating medium pipeline. The steam drum has a water inlet connected to a water supply pipeline and a steam outlet connected to a steam pipeline. The coil quenching device consists of multiple layers of coils arranged along the height, with the diameter of the upper coil being larger than that of the lower coil.

2. The vertical furnace coil-type quenching and waste heat recovery system according to claim 1, characterized in that, The multi-layer coil consists of 3 to 5 spiral coils; the top 2 to 3 spiral coils are the upper coils, with a diameter of ø50 to ø80 mm, and the bottom 2 to 3 spiral coils are the lower coils, with a diameter of ø30 to ø50 mm.

3. The vertical furnace coil-type quenching and waste heat recovery system according to claim 1, characterized in that, Each layer of spiral coil has an independent medium inlet and medium outlet, and the spiral coils of each layer are connected in parallel to the circulating medium pipeline.

4. A vertical furnace coil-type quenching and waste heat recovery system according to claim 1 or 2, characterized in that, The upper coil is made of 310S heat-resistant steel, and the lower coil is made of 304 stainless steel.

5. A vertical furnace coil-type quenching and waste heat recovery system according to claim 1, characterized in that, The coke quenching channel is made of heat-resistant steel pipe, with a diameter of 0.5 to 1 m and a height of 3 to 5 m; a coke discharge valve and a temperature detection device are installed at the coke outlet at the bottom of the coke quenching channel.

6. A vertical furnace coil-type quenching and waste heat recovery system according to claim 1, characterized in that, It also includes a coke quenching temperature control system; the coke quenching temperature control system consists of a red coke temperature sensor located between each layer of spiral coils, an inlet pressure sensor and an inlet medium temperature sensor located at the medium inlet of each layer of spiral coils, an outlet pressure sensor and an outlet medium temperature sensor located at the medium outlet of each layer of spiral coils, and a PLC controller; the PLC controller is also connected to the control terminal of the forced circulation pump.

7. A vertical furnace coil-type quenching and waste heat recovery system according to claim 1, characterized in that, It also includes a demineralized water tank, a deoxygenated water pump, a deaerator, a feed water pump, and a steam distribution cylinder; the demineralized water tank is connected to the inlet of the deaerator through a demineralized water pipeline, the outlet of the deaerator is connected to the steam drum through a water supply pipeline, and a feed water pump is installed on the water supply pipeline; the steam drum is connected to the steam inlet of the steam distribution cylinder through a steam pipeline, and the steam outlet of the steam distribution cylinder is connected to the steam inlet of the deaerator and the external steam pipeline respectively.

8. A vertical furnace coil-type quenching and waste heat recovery system according to claim 1, characterized in that, The flow rate of the forced circulation pump is 50-100 m³ / h. 3 / h.

9. A method for vertical furnace coil quenching and waste heat recovery based on the vertical furnace coil quenching and waste heat recovery system as described in claims 1-3 and 5-8, characterized in that, The process includes the following: (1) The coal is continuously carbonized in the carbonization chamber of the vertical furnace. The red coke at 500-800℃ is continuously and uniformly discharged into multiple quenching channels through the star-shaped discharge valve and moves slowly from top to bottom. The residence time of the red coke in the quenching channel is 60-150 minutes. (2) The demineralized water in the steam drum enters each layer of spiral coil of the coil quenching device through the circulating medium pipeline. After exchanging heat with the red coke, the temperature rises and then steam is generated through the steam drum. The steam is sent to the steam distribution cylinder, and part of the steam is sent to the deaerator to preheat the demineralized water extracted from the demineralized water tank to 100-120°C. The preheated demineralized water is used as the circulating medium and is supplied to the circulating medium pipeline through the steam drum. (3) During the descent of the red coke in the quenching channel, it first exchanges heat with the circulating medium in the upper coil and cools down to 300-500℃ before exchanging heat with the circulating medium in the lower coil. The flow rate of the circulating medium in each spiral coil is adjusted by the quenching temperature control system to control the cooling rate of the red coke to 8-10℃ / min. (4) The high-temperature steam-water mixture with a temperature of 400-450°C after heat exchange with the red coke in the coil quenching device is sent into the steam drum to generate saturated steam of 0.8-1.2MPa. The saturated steam is directly sent out for use; or the saturated steam is sent back into the coil quenching device as a circulating medium to exchange heat with the red coke, and superheated steam is generated through the steam drum and sent out for use. (5) When the temperature detection device at the bottom of the coke outlet of the quenching channel detects that the red coke temperature has dropped below 150°C, the coke is discharged through the coke discharge valve.

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