CN111302338B - Equipment and method for preparing amorphous desulfurization and denitrification active coke by one-step method - Google Patents

Abstract

The invention relates to an in-situ preparation process and method of active coke suitable for flue gas treatment, in particular to an equipment and method for preparing amorphous desulfurization and denitrification active coke in one step. The equipment includes a gas purification system connected to the coke oven, a power plant boiler system and a steam heating furnace; the inside of the coke oven is divided into a carbonization section and an activation section. The cooling section of the cooling section; the top of the carbonization section is provided with a raw material inlet and a gas outlet; the raw material inlet is connected to the outlet of the silo section; the gas outlet is connected to the gas purification system inlet; the gas purification system outlet is connected to the boiler system of the power plant and the steam heating furnace respectively The gas inlet of the power plant boiler system is connected to the steam inlet of the steam heating furnace; the activation section is equipped with a multi-layer injection system, and the furnace wall of the activation section is equipped with a high-temperature steam inlet connected to the multi-layer injection system; the high-temperature steam inlet It is communicated with the steam outlet of the steam heating furnace, and a post-combustion air pipe is also arranged on it.

Description

Equipment and method for preparing amorphous desulfurization and denitrification active coke by one-step method

technical field

The invention relates to an in-situ preparation process and method of active coke suitable for flue gas treatment, in particular to an equipment and method for preparing amorphous desulfurization and denitrification active coke in one step.

Background technique

Most of my country's coal-fired power plants have achieved ultra-low emissions, and the pollutant treatment has reached the world's leading level. However, the pollutant treatment process is single, wet desulfurization leads to excessive exploitation of limestone resources, and a large amount of low-quality gypsum is produced by-products, resulting in secondary pollution. At the same time, my country is a large agricultural country with a shortage of sulfur resources. In 2018, the consumption of sulfur reached 17 million tons, and the imported sulfur reached 11 million tons. Therefore, it is the direction and inevitable trend of the development of my country's environmental protection technology to develop a new comprehensive pollutant treatment technology that is coordinated with the power production process, and then realize the resource utilization of sulfur.

On the other hand, the level of pollution control in industries such as metallurgy, coking, industrial boilers (kilns), biomass power plants, and waste incineration power plants is relatively backward, and it is the focus of my country's next step in environmental governance. Coal-fired power plants generally use limestone-gypsum wet desulfurization + electrostatic precipitator + selective catalytic reduction (SCR) denitrification. The process is complicated and the investment and operation costs are high, which is not suitable for popularization and application in small and medium-sized boilers. At the same time, the operating conditions of industrial boilers are complex and limited by the temperature window. The existing SCR and SNCR are difficult to meet the long-term stable operation requirements. Denitrification technology cannot be used. Therefore, low-temperature denitrification technology is an urgent need for flue gas treatment in non-electric industries.

Activated coke flue gas comprehensive purification technology is an advanced flue gas pollution control technology. Its raw material comes from coal, and the by-products can be directly fed into the boiler for combustion, which can achieve a high degree of synergy with the power production process. At the same time, it has high desulfurization efficiency, can achieve low-temperature denitrification, realizes high-value utilization of sulfur resources, and does not have visual pollution such as "smoke plume phenomenon". It is currently the most promising alternative process for pollution control. Up to now, more than 30 units (sets) have been in operation, and the largest scale is 600m2 sintering machine in Taiyuan Iron and Steel Plant.

The existing activated coke flue gas purification technology uses cylindrical activated coke, the preparation process is complicated, it is not suitable for in-situ preparation, and the cost is high, and the desulfurization and denitrification performance is poor, resulting in high investment and operation costs of the entire process.

Contents of the invention

Aiming at the problems existing in the prior art, the present invention provides equipment and method for preparing amorphous desulfurization and denitrification active coke by one-step method, adopting raw coal one-step method to prepare amorphous active coke, which can be used for in-situ preparation of active coke, and improves the desulfurization and denitrification performance of active coke , simplify the active coke production process, and greatly reduce the cost of active coke preparation.

The present invention is achieved through the following technical solutions:

One-step preparation of amorphous desulfurization and denitrification active coke equipment, including coke ovens, gas purification systems, power plant boiler systems and steam heating furnaces connected in sequence with the coke ovens;

The inside of the coke oven is divided into a carbonization section and an activation section from top to bottom, the top is provided with a bunker section connected to the carbonization section, and the bottom is provided with a cooling section connected to the activation section; the bottom of the cooling section is provided with a discharge mouth;

The top of the carbonization section is provided with a raw material inlet and a gas outlet; the raw material inlet is connected to the outlet of the silo section through a material slide pipe; the gas outlet is connected to the inlet of the gas purification system through a pipeline; the outlet of the gas purification system The gas ports are respectively connected to the gas inlets of the boiler system of the power plant and the steam heating furnace; the steam outlet of the boiler system of the power plant is connected to the steam inlet of the steam heating furnace;

The interior of the activation section is provided with a multi-layer injection system, and the furnace wall of the activation section is provided with a high-temperature steam inlet connected to the multi-layer injection system; the high-temperature steam inlet communicates with the steam outlet of the steam heating furnace through a pipeline, and the high-temperature steam inlet There is also a post-combustion air pipe communicated with it.

Further, the multi-layer injection system includes several injection units arranged at intervals from top to bottom in the activation section; the number of injection units is connected with the high-temperature steam inlets on the furnace wall of the activation section in one-to-one correspondence, and the injection units include uniform The nozzles arranged in communication, the openings of the nozzles are arranged downwards.

Further, a circulating cooling water pipe is arranged inside the cooling section; the water inlet and outlet of the circulating cooling water pipe are connected to the cooling water system of the power plant.

Furthermore, the circulating cooling water pipe adopts a serpentine pipe arranged horizontally in the cooling section.

Further, the discharge opening of the cooling section is conical, and a discharge valve is provided at the bottom end, and a conveyor belt connected to the active coke storage unit is provided below the discharge valve.

Further, a feed valve is set on the chute.

A method for preparing amorphous desulfurization and denitrification activated coke in one step, comprising the following steps:

Step 1. Send the raw materials used for coking into the silo section, and then enter the carbonization section of the coke oven through the material slide pipe, and generate gas in the carbonization section of the coke oven. The generated gas enters the gas purification system through the gas outlet, and the remaining materials are Enter the activation section from top to bottom;

Step 2, the gas entering the gas purification system is purified to form clean gas, most of the clean gas enters the boiler system of the power plant for combustion, and a small part of the clean gas enters the steam heating furnace to heat the steam from the boiler system of the power plant to form high-temperature steam; high-temperature steam and supplementary combustion The air is mixed into the multi-layer injection system to form a high-temperature steam flow from top to bottom, and directly contacts with the material entering the activation section from top to bottom, and the material is heated and carbonized to form active coke;

In step 3, the active coke enters the cooling section and indirectly contacts with the circulating cooling water pipe in the cooling section to cool the active coke to below 100°C, and then transports the active coke to the active coke storage unit through the conveyor belt.

Further, in step 1, the raw material used for coking is raw coal, the particle size is 4-15mm, the sulfur content is less than 1%, and the ash content is less than 8%, and the active coke obtained is unshaped active coke.

Further, in step 2, the activation process in the activation section uses high-temperature steam for activation, and the steam is heated to 800-900° C. before entering the activation section.

Further, in step 2, high-temperature steam and supplementary combustion air are mixed into the multi-layer injection system, and the temperature of the carbonization section is adjusted by regulating the amount of high-temperature steam and supplementary combustion air in each layer.

Compared with the prior art, the present invention has the following beneficial technical effects:

The present invention prepares unshaped active coke by adopting carbonization and activation integrated equipment, the preparation process is simple, the investment cost is low, and active coke can be prepared in situ, and the cost of coke making is only one-third of the original cost, thereby greatly reducing the active coke joint cost. The operating cost of desulfurization and denitrification process; moreover, using unshaped raw coal as raw material, the activated coke prepared retains the medium and large pore structure of the raw coal, and combines with the microporous structure prepared during the activation process to form a dendritic pore structure, which is suitable for SO ₂ , NO _x The diffusion and adsorption of gas molecules, etc., the removal effect is obviously better than that of the existing active coke. Compared with the existing active coke combined desulfurization and denitrification process, the reaction time is shortened, and the loading amount of active coke is reduced, thereby reducing equipment investment costs. Due to the use of raw coal as raw material, the gas produced is directly used for boiler combustion, and the steam used in the coking process is provided by the boiler, which realizes the synergy with the power production process; at the same time, it effectively solves the investment in the existing active coke combined desulfurization and denitrification technology It is of great significance to promote the progress of activated coke desulfurization and denitrification technology and the upgrading of environmental protection technology.

The invention maintains the thermal balance of the carbonization and activation process by introducing air for supplementary combustion, and maintains a constant temperature in each section by adjusting the amount of supplementary combustion air. The control is convenient and the structure is simple.

Description of drawings

Fig. 1 is a schematic diagram of the equipment structure of the present invention.

In the figure: silo section 1, slide pipe 2, feed valve 3, carbonization section 4, activation section 5, multi-layer injection system 6, cooling section 7, circulating cooling water pipe 8, discharge valve 9, gas outlet 10, Gas purification system 11, power plant boiler system 12, steam heating furnace 13, power plant cooling water system 14, conveyor belt 15, active coke storage unit 16.

Detailed ways

The present invention will be further described in detail below in conjunction with specific embodiments, which are explanations of the present invention rather than limitations.

Example 1

The present invention prepares amorphous desulfurization and denitrification activated coke equipment in one step, as shown in Figure 1, comprising a silo section 1, a material slide pipe 2, a carbonization section 4, an activation section 5, and a cooling section 7 connected sequentially from top to bottom; The feed valve 3 is set on the feed pipe 2, the discharge valve 9 is set at the bottom of the cooling section 7, and the gas outlet 10 is set at the top of the carbonization section 4, which is connected with the gas purification system 11, and the purified gas enters the power plant boiler system 12 and steam respectively. The heating furnace 13 and the steam required by the steam heating furnace 13 are supplied by the boiler system 12 of the power station. The high-temperature steam at the outlet of the steam heating furnace 13 is mixed with the post-combustion air and enters the activation section 5 through the multi-layer injection system 6. The bottom-up high-temperature gas generated in the activation section 5 directly contacts with the material entering the carbonization section 4 from top to bottom. It is heated and carbonized, and the volatile matter precipitated during the carbonization process enters the gas purification system 11 together with the gas in the activation section. A circulating cooling water pipe 8 is arranged in the cooling section 7, and the circulating cooling water pipe 8 is connected to the cooling water system 14 of the power plant.

As a preferred embodiment of the present invention, the raw material used for coking is raw coal, the particle size is 4-15mm, the sulfur content is less than 1%, and the ash content is less than 8%, and the obtained product is unshaped active coke.

As a preferred embodiment of the present invention, the carbonization process and the activation process are carried out in the same reactor, that is, a one-step method is used to prepare active coke.

As a preferred embodiment of the present invention, the activation process uses high-temperature steam for activation, and the steam is heated to 800-900° C. before entering the activation section 5 .

As a preferred embodiment of the present invention, the activation section 5 adopts a multi-layer steam injection system 6 to ensure sufficient contact between the active coke and steam, and ensure the stable properties of the active coke. The method of injecting supplementary combustion air into the activation section 5 meets the heat balance requirements of the carbonization section 4, and the multi-layer injection also ensures the temperature stability of the carbonization section 4.

Example 2

The present invention prepares the amorphous desulfurization and denitrification activated coke method in one step, and the steps are as follows,

Granular coal with a particle size of 4-15mm, sulfur content <1%, and ash content <8% enters the silo section 1, and enters the coke oven through the slide pipe 2, and the gas produced by the coke oven passes through the gas outlet at the top of the carbonization section 4 10 enters the gas purification system 11, most of the purified gas enters the boiler system 12 of the power plant for combustion, and a small part enters the steam heating furnace 13 to heat the steam from the boiler system 12 of the power plant to 800-900°C, and the high-temperature steam is mixed with supplemental combustion air into the The multi-layer injection system 6 ensures the temperature of the carbonization section 4 and the quality of active coke to be stable by regulating the amount of steam in each layer and the amount of post-combustion air. The high-temperature gas generated in the activation section 5 enters the carbonization section 4 from bottom to top, and directly contacts with the top-down material in the carbonization section 4 to heat the material to achieve carbonization. The active coke produced in the activation section 5 enters the cooling section 7 and indirectly contacts the circulating cooling water pipe 8 in the cooling section 7 to cool the active coke to below 100°C, and then transports it to the active coke storage unit 16 through the conveyor belt 15 .

Adopting the equipment and method of the present invention to prepare amorphous desulfurization and denitrification active coke has a simple process and is suitable for in-situ coke making by sintering machines in coal-fired power plants or steel mills. The produced active coke has the characteristics of accessible medium and large pores and well-developed micropores. The performance is obviously better than commercial active coke, and the production cost of desulfurization and denitrification active coke is greatly reduced. The prepared active coke can be widely used in coal-fired power plants, steel plants, metallurgy and other fields to treat flue gas.

Claims (8)

1. The method for preparing the amorphous desulfurization and denitrification active coke by the one-step method is based on equipment for preparing the amorphous desulfurization and denitrification active coke by the one-step method and is characterized in that,

the equipment comprises a coke making furnace, a gas purifying system (11), a power plant boiler system (12) and a steam heating furnace (13) which are sequentially connected with the coke making furnace;

the inside of the coke oven is divided into a carbonization section (4) and an activation section (5) from top to bottom, the top is provided with a storage bin section (1) communicated with the carbonization section (4), and the bottom is provided with a cooling section (7) communicated with the activation section (5); the bottom of the cooling section (7) is provided with a discharge opening;

the top of the carbonization section (4) is provided with a raw material inlet and a coal gas outlet (10); the raw material inlet is connected with a discharge hole of the stock bin section (1) through a material sliding pipe (2); the gas outlet (10) is connected with a gas inlet of the gas purifying system (11) through a pipeline; the gas outlet of the gas purifying system (11) is respectively connected with the gas inlets of the power plant boiler system (12) and the steam heating furnace (13); the steam outlet of the power plant boiler system (12) is connected with the steam inlet of the steam heating furnace (13);

a multi-layer injection system (6) is arranged in the activation section (5), and a high-temperature steam inlet connected with the multi-layer injection system (6) is arranged on the furnace wall of the activation section (5); the high-temperature steam inlet is communicated with a steam outlet of a steam heating furnace (13) through a pipeline, and is also communicated with a post-combustion air pipe;

the method comprises the following steps:

step 1, raw coal adopted in coke making is sent into a bin section (1), then enters a coke making furnace carbonization section (4) through a chute (2), gas is generated in the coke making furnace carbonization section (4), the generated gas enters a gas purification system (11) through a gas outlet (10), and the rest materials enter an activation section (5) from top to bottom; raw coal grain size is 4-15 mm, sulfur content is less than 1%, ash content is less than 8%;

step 2, purifying the gas entering the gas purifying system (11) to form clean gas, wherein most of the clean gas enters the power plant boiler system (12) for combustion, and a small part of the clean gas enters the steam heating furnace (13) for heating steam from the power plant boiler system (12) to form high-temperature steam; the high-temperature steam and the afterburning air are mixed and enter a multi-layer injection system (6) to form a high-temperature steam flow from top to bottom, and the high-temperature steam flow is directly contacted with materials entering an activation section (5) from top to bottom, and the materials are heated and carbonized to form unshaped active coke;

and 3, enabling the unshaped active coke to enter a cooling section (7), indirectly contacting with a circulating cooling water pipe (8) in the cooling section (7), cooling the unshaped active coke to below 100 ℃, and conveying the unshaped active coke to an active coke storage unit (16) through a conveying belt (15), wherein the active coke is a dendritic pore structure formed by combining a medium-large pore structure of raw coal with an activation process.

2. The method for preparing amorphous desulfurization and denitrification active coke according to claim 1, wherein in the step 2, the activation process in the activation section (5) is activated by high-temperature steam, and the steam is heated to 800-900 ℃ before entering the activation section (5).

3. The method for preparing the amorphous desulfurization and denitrification active coke according to the one-step method of claim 1, wherein in the step 2, high-temperature steam and afterburning air are mixed into a multi-layer injection system (6), and the temperature of the carbonization section (4) is adjusted by regulating the amount of the high-temperature steam and the amount of the afterburning air of each layer.

4. The method for preparing the amorphous desulfurization and denitrification active coke according to the one-step method of claim 1, wherein the multi-layer injection system (6) comprises a plurality of injection units which are arranged in the activation section (5) from top to bottom at intervals; the number of the spraying units is in one-to-one correspondence with the high-temperature steam inlets on the furnace wall of the activation section (5), the spraying units comprise nozzles which are uniformly communicated and arranged, and the openings of the nozzles are downwards arranged.

5. The method for preparing the amorphous desulfurization and denitrification active coke according to the one-step method of claim 1, which is characterized in that a circulating cooling water pipe (8) is arranged in the cooling section (7); the water inlet and the water outlet of the circulating cooling water pipe (8) are connected with a power plant cooling water system (14).

6. The method for preparing the amorphous desulfurization and denitrification active coke according to the one-step method of claim 1, wherein the circulating cooling water pipe (8) adopts a serpentine pipe which is horizontally arranged in the cooling section (7).

7. The method for preparing the amorphous desulfurization and denitrification active coke according to the one-step method of claim 1, wherein the discharge opening of the cooling section (7) is conical, the bottom end of the cooling section is provided with a discharge valve (9), and a conveying belt (15) connected with an active coke storage unit (16) is arranged below the discharge valve (9).

8. The method for preparing the amorphous desulfurization and denitrification active coke by the one-step method according to claim 1, wherein a feed valve (3) is arranged on the chute (2).