Raw gas conveying pipeline

Abstract

The utility model relates to a raw gas conveying pipeline which comprises a pipeline body and a composite sealing heat insulation lining arranged in the pipeline body. The pipeline body is made of carbon steel, and the composite sealing heat insulation lining is composed of a refractory brick supporting layer, a sealing layer and a heat insulation layer which are sequentially arranged from inside to outside. According to the utility model, while the pipeline investment is reduced and the service life of the pipeline lining is greatly prolonged, the problem that the heat insulation effect of the pipeline is invalid due to the fact that tar and other substances in the high-temperature raw gas permeate into the heat insulation layer is avoided, and long-distance stable conveying of the high-temperature raw gas in the direct reforming process is realized.

Description

Technical Field

[0001] The utility model relates to the technical field of coking production, in particular to a high-temperature raw coke oven gas transmission pipeline. Background Technique

[0002] In order to cope with global climate change and respond to the call of "carbon emission reduction and carbon neutralization", the demand for hydrogen by production enterprises has increased sharply. The high-temperature raw coke oven gas at 650-800°C released during the coking process contains a large amount of H2, CH4, etc., and can be used as one of the hydrogen sources with lower costs. The existing raw coke oven gas treatment process is to spray the high-temperature raw coke oven gas coming out of the coke oven with ammonia water to cool it down to 80-90°C, then send it to the chemical production unit for purification, and finally reform the purified clean coke oven gas; the process flow is complex, the investment is high, and at the same time, a large amount of sensible heat in the high-temperature raw coke oven gas is wasted.

[0003] The process of directly sending the high-temperature raw coke oven gas coming out of the coke oven into the reforming furnace for direct reforming without cooling and purification can not only shorten the process flow, reduce equipment investment, but also utilize the sensible heat of the high-temperature raw coke oven gas itself to reduce production energy consumption; in addition, impurities such as tar and coke powder in the raw coke oven gas can be reformed, greatly increasing the production of syngas H2 and CO, which is a very promising hydrogen production technology.

[0004] For the direct reforming process of high-temperature raw coke oven gas, the high-temperature raw coke oven gas needs to be directly transported from the coke oven to the reforming furnace after being led out. The composition of the high-temperature raw coke oven gas is complex. In addition to combustible gases such as H2, CH4, and CO, it also contains corrosive impurities such as tar, coke dust, H2S, NH3, and HCl. In order to prevent heat loss of the high-temperature raw coke oven gas and deposition and blockage of substances such as tar in the pipeline, a jacketed raw coke oven gas transmission pipeline structure is often used (such as the Chinese patent applications with publication numbers CN 110778842 A and CN 114923123A), and the heat preservation transportation of the raw coke oven gas is realized by introducing heating gas or high-temperature gas into the jacket. The jacket structure using refractory bricks is complex, the project investment is large, and problems such as leakage and even high-temperature graphite formation are likely to occur, affecting the safety during the transportation of combustible gases in the pipeline. Since the temperature of the high-temperature raw coke oven gas can reach 650-800°C, and the condensation temperature of the tar in it is 400-565°C under normal pressure, even if the jacket structure is not adopted, as long as a reasonable heat preservation structure is adopted and the gas flow rate of the raw coke oven gas is controlled to ensure that the temperature of the high-temperature raw coke oven gas before entering the reforming furnace is above 565°C, the deposition of tar in the high-temperature raw coke oven gas in the pipeline can be avoided.

[0005] Due to the high temperature and corrosive characteristics of high-temperature crude gas, when the insulation structure is set on the outside of the pipeline, the material requirements of the pipeline itself are very high, and special heat-resistant stainless steel is required, which will greatly increase the investment cost. If the insulation and anti-corrosion resistant material lining is set on the inside of the crude gas transmission pipeline, the pipeline can be made of ordinary carbon steel, which greatly reduces the investment. The commonly used lining structure is the castable lining structure, which is connected to the pipeline through anchor nails. However, due to the inconsistency of the expansion coefficients of the anchor nails and the castable, the castable layer is prone to cracking and falling off in a long-term high temperature environment, causing the service life of the crude gas transmission pipeline to drop sharply. For the lining structure using refractory bricks + insulation bricks, since tar will penetrate into the pores inside the insulation bricks through the ash joints and expansion joints of the heavy refractory bricks, the insulation performance of the insulation bricks will decrease, so the insulation performance of the crude gas transmission pipeline will also decrease rapidly, eventually leading to tar deposition and clogging of the pipeline. Summary of the invention

[0006] The utility model provides a raw coal gas transmission pipeline, which adopts a composite sealed heat-insulating lining composed of a refractory brick support layer, a sealing layer and a heat-insulating layer. The pipeline body is made of ordinary carbon steel. While reducing pipeline investment and greatly extending the life of the pipeline lining, it avoids the problem of failure of pipeline insulation due to the penetration of tar and other substances in the high-temperature raw coal gas into the heat-insulating layer, thereby realizing long-distance and stable transportation of high-temperature raw coal gas in the direct reforming process.

[0007] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0008] A raw gas transmission pipeline comprises a pipeline body and a composite sealing and heat-insulating lining arranged in the pipeline body; the pipeline body is made of carbon steel, and the composite sealing and heat-insulating lining consists of a refractory brick supporting layer, a sealing layer and a heat-insulating layer arranged in sequence from the inside to the outside.

[0009] Furthermore, the refractory brick support layer is a cylindrical structure formed by a number of high-strength refractory bricks, and the mortar joint is 2 to 3 mm; two adjacent high-strength refractory bricks are connected by groove and tongue bite; the thickness of the refractory brick support layer is at least 80 mm, and the high-strength refractory bricks are silicon-aluminum refractory bricks with a compressive strength of not less than 20 MPa.

[0010] Furthermore, the sealing layer is a cylindrical structure composed of sealing refractory bricks, the circumferential size of the sealing refractory bricks is larger than the circumferential size of the high-strength refractory bricks, the thickness of the sealing refractory bricks is not less than 50 mm, and the compressive strength is not less than 10 MPa; the sealing refractory bricks and the high-strength refractory bricks of the supporting layer are staggered.

[0011] Furthermore, the sealing layer is a cylindrical structure composed of refractory castable. The thickness of the sealing layer is not less than 50 mm, and the room temperature flexural strength of the refractory castable is not less than 2 MPa.

[0012] Furthermore, the sealing layer is a cylindrical structure made of heat-resistant stainless steel plate. The thickness of the heat-resistant stainless steel plate is 0.2 - 2.0 mm; the lap width of the heat-resistant stainless steel plate is at least 75 mm.

[0013] Furthermore, the heat insulation layer is a cylindrical structure composed of heat insulation bricks or heat insulation castable. The thermal conductivity of the heat insulation bricks or heat insulation castable is less than 0.6 W / m·K, and the thickness of the heat insulation layer is not less than 50 mm.

[0014] Furthermore, an axial expansion joint is arranged every 1 - 2 m along the axial direction of the pipeline for both the refractory brick support layer and the sealing layer. The axial expansion joint is filled with ceramic fiber blanket; the axial expansion joints of the refractory brick support layer and the sealing layer are spaced more than 50 mm apart and staggered.

[0015] Furthermore, a circumferential expansion joint is arranged between the heat insulation layer and the sealing layer of the composite sealing and heat insulation lining, or between the heat insulation layer and the pipeline body. The width of the circumferential expansion joint is 5 - 10 mm, and the circumferential expansion joint is filled with ceramic fiber blanket.

[0016] Furthermore, an external thermal insulation layer is provided outside the pipeline body.

[0017] Compared with the prior art, the beneficial effects of the present utility model are as follows:

[0018] (1) By adopting a composite sealing and heat insulation lining composed of a refractory brick support layer, a sealing layer and a heat insulation layer, and increasing the flow velocity of raw coal gas in the pipeline, it is ensured that the temperature of the high-temperature raw coal gas before entering the reforming furnace is above 565 °C, avoiding the deposition of tar in the high-temperature raw coal gas in the pipeline.

[0019] (2) The pipeline lining structure has the functions of heat insulation and heat preservation, and measures such as heating gas tracing and heat preservation commonly used in high-temperature raw coal gas transmission pipelines can be cancelled.

[0020] (3) The material of the pipeline body can be ordinary carbon steel. Compared with pipelines made of heat-resistant stainless steel, a large amount of investment is saved.

[0021] (4) Compared with the raw coal gas transmission pipeline with a conventional lining structure, it can avoid the problem that the heat insulation effect of the pipeline fails due to substances such as tar in the high-temperature raw coal gas penetrating into the heat insulation layer, realizing the long-distance and stable transmission of high-temperature raw coal gas, which is beneficial to the smooth operation of the reforming furnace production. Description of the Drawings

[0022] Figure 1It is a schematic cross-sectional structure diagram of a waste gas conveying pipeline of the present utility model.

[0023] Figure 2 It is a schematic cross-sectional structure diagram of a high-temperature waste gas conveying pipeline in Embodiment 1 of the present utility model.

[0024] Figure 3 Is Figure 2 The A-A cross-sectional view in

[0025] Figure 4 It is a schematic cross-sectional structure diagram of a high-temperature waste gas conveying pipeline in Embodiment 2 of the present utility model.

[0026] Figure 5 It is a schematic cross-sectional structure diagram of a high-temperature waste gas conveying pipeline in Embodiment 3 of the present utility model.

[0027] In the figure: 1. Refractory brick support layer; 2. Sealing layer; 21. Sealing refractory brick; 22. Refractory castable; 23. Heat-resistant stainless steel plate; 3. Heat insulation layer; 4. Circumferential expansion joint; 5. Pipeline body; 6. Axial expansion joint Detailed implementation manners

[0028] The following further explains the detailed implementation manners of the present utility model with reference to the accompanying drawings:

[0029] As Figure 1 shown, a waste gas conveying pipeline of the present utility model is composed of a pipeline body 5 made of ordinary carbon steel and a composite sealing and heat insulation lining inside it. The composite sealing and heat insulation lining is composed of a refractory brick support layer 1, a sealing layer 2, and a heat insulation layer 3 from the inside out. Among them, the refractory brick support layer 1 supports the composite sealing and heat insulation lining. The main function of the sealing layer 2 is to prevent substances such as tar in the high-temperature waste gas from penetrating through the refractory brick support layer 1 into the heat insulation layer 3, and the heat insulation layer 3 plays a role in heat insulation and heat preservation.

[0030] The refractory brick support layer 1 of the present utility model is a cylindrical structure made of several high-strength refractory bricks. The mortar joint between the bricks is controlled within 2 - 3 mm, and the bricks are connected by groove and tongue joints to ensure the structural stability of the refractory brick support layer 1. High-strength refractory bricks are preferably alumina-silicate refractory bricks. The thickness of the refractory brick support layer 1 is at least 80 mm, and the compressive strength is not less than 20 MPa to ensure the structural strength of the refractory support layer 1 and the overall service life of the composite sealing and heat insulation lining. If the refractory brick support layer 1 is replaced with castable pouring, its service life is generally within 5 years, and regular maintenance and replacement are required; while the present utility model uses high-strength refractory bricks for masonry, which can ensure a service life of more than 20 years and greatly reduce the maintenance workload.

[0031] The sealing layer 2 of the present utility model can be constructed by refractory sealing bricks 21. The refractory sealing bricks 21 adopt a large-sized arc-shaped brick type to reduce the number of mortar joints. The thickness of the sealing layer 2 made of the refractory sealing bricks 21 is not less than 50 mm, and the compressive strength of the used refractory sealing bricks 21 is not less than 10 MPa to ensure the overall strength of the sealing layer 2 and prevent it from being crushed by the refractory brick support layer 1. The refractory sealing bricks 21 are laid with staggered joints with the high-strength refractory bricks of the refractory brick support layer 1, and continuous joints are avoided between the two-layer structures to prevent the tar in the high-temperature raw coal gas from penetrating inwards.

[0032] The sealing layer 2 of the present utility model can also be formed by refractory castable 22. The thickness of the sealing layer 2 made of the refractory castable 22 is not less than 50 mm, and the room-temperature flexural strength of the used refractory castable 22 is not less than 2 MPa to ensure the overall structural strength of the sealing layer 2 and prevent phenomena such as fragmentation.

[0033] The sealing layer 2 of the present utility model can also be made of heat-resistant stainless steel plate 23. The thickness of the sealing layer 2 made of the heat-resistant stainless steel plate 23 is 0.2 - 2.0 mm, and the overlapping width of the heat-resistant stainless steel plate 23 is at least 75 mm to prevent the high-temperature raw coal gas from leaking through the joints of the heat-resistant stainless steel plate 23. To ensure the structural stability of the sealing layer 2 made of the heat-resistant stainless steel plate 23, two adjacent heat-resistant stainless steel plates 23 can be fixed with stainless steel rivets.

[0034] The heat-insulating layer 3 of the present utility model is composed of heat-insulating bricks or heat-insulating castable. The thermal conductivity of the heat-insulating bricks or heat-insulating castable is less than 0.6 W / m·K, and the thickness of the heat-insulating layer 3 is not less than 50 mm to ensure the heat-insulating effect and structural strength.

[0035] An axial expansion joint 6 is arranged on the refractory brick support layer 1 and the sealing layer 2 along the axial direction of the pipeline at intervals of 1 - 2 m. The width of the axial expansion joint 6 is 5 - 10 mm, and it is filled with ceramic fiber blanket to compensate for thermal expansion. The axial expansion joints of the refractory brick support layer 1 and the sealing layer 2 are arranged staggeredly, and the interval between them is more than 50 mm to prevent substances such as tar in the high-temperature raw coal gas from penetrating into the heat-insulating layer 3 through the axial expansion joint 6.

[0036] A circumferential expansion joint 4 with a width of 5 - 10 mm is arranged inside the composite sealing and heat-insulating lining of the present utility model or between it and the pipeline body 5, and it is filled with ceramic fiber blanket to absorb the circumferential expansion of the composite sealing and heat-insulating lining. The circumferential expansion joint 4 can be arranged between the pipeline body 5 and the heat-insulating layer 3, or between the heat-insulating layer 3 and the sealing layer 2.

[0037] In addition to the composite sealing and heat-insulating lining arranged on the inner side of the pipeline body 5 of the present utility model, an external heat-insulating layer can also be made on its outer side to further reduce the temperature of the pipeline outer wall.

[0038] Before the waste gas conveying pipeline of the present utility model is put into use, an external heat source is required to bake the composite sealing and heat-insulating lining. After the temperature of the refractory brick support layer 1 inside reaches above 600 °C, nitrogen is used to displace the gas inside the pipeline, and then it can be put into use; when in use, the flow rate of the high-temperature waste gas in the pipeline is preferably controlled between 10 and 30 m / s. Preheating the pipeline lining can prevent the high-temperature waste gas from directly contacting the high-strength refractory bricks of the refractory brick support layer 1 and condensing on its surface. Controlling the flow rate of the high-temperature waste gas in the pipeline can prevent the dust in the high-temperature waste gas from settling and blocking the pipeline.

[0039] The refractory brick support layer 1 described in the present utility model is built into a cylindrical structure by high-strength refractory bricks, forming a high-strength and long-life support layer, and at the same time preventing the erosion of the waste gas on the pipeline; the sealing layer 2 is made of sealing refractory bricks 21, refractory castables 22 or heat-resistant stainless steel plates 23, which can prevent substances such as tar in the waste gas from penetrating into the heat-insulating layer 3; the heat-insulating layer 3 is composed of heat-insulating bricks or heat-insulating castables, which play a role in heat insulation and heat preservation. By setting a composite lining structure composed of a refractory brick support layer 1 - sealing layer 2 - heat-insulating layer 3 in the pipeline, the structural strength of the lining is enhanced, the service life of the lining is extended, and at the same time, substances such as tar in the waste gas are prevented from penetrating into the heat-insulating layer 3 and causing the heat-insulating layer 3 to fail, which can play a long-term role in heat insulation and heat preservation.

[0040] To make the purpose, technical solution and technical effect of the present utility model clearer, the technical solutions in the embodiments of the present utility model are now described clearly and completely. However, the embodiments described below are only a part of the embodiments of the present utility model, rather than all the embodiments. Combining the embodiments in the present utility model, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the protection scope of the present utility model.

[0041]

Embodiment 1

[0042] As Figures 2 - 3 shown, in this embodiment, the pipeline body 5 of the waste gas conveying pipeline is made of ordinary carbon steel, and the composite sealing and heat-insulating lining is composed of a refractory brick support layer 1, a sealing layer 2 made of refractory bricks, and a heat-insulating layer 3 made of heat-insulating bricks.

[0043] In this embodiment, the high-strength refractory bricks of the refractory brick support layer 1 are made of clay bricks, and the bricks are connected by tongue-and-groove bite. The thickness of the refractory brick support layer 1 is 200 mm, and the compressive strength is not less than 25 MPa.

[0044] In this embodiment, the sealing refractory bricks 21 of the sealing layer 2 are made of cenospheres bricks. The cenospheres bricks are in the shape of large arc-shaped bricks, the outer arc length is 300 mm, the thickness is 65 mm, and the compressive strength is 10 MPa. The cenospheres bricks and the clay bricks of the refractory brick support layer 1 are laid with staggered joints to avoid the generation of through joints.

[0045] In this embodiment, the heat insulation layer 3 is made of heat-insulating bricks, the thermal conductivity of the heat-insulating bricks is not greater than 0.15 W / m·K, and the thickness of the heat insulation layer 3 is 90 mm.

[0046] In this embodiment, an axial expansion joint 6 is provided every 1500 mm in both the refractory brick support layer 1 and the sealing layer 2. The width of the axial expansion joint 6 is 7 mm, and it is filled with ceramic fiber blankets. The axial expansion joints of the refractory brick support layer 1 are staggered from those of the sealing layer 2 by 75 mm. A circumferential expansion joint 4 with a width of 6 mm is provided between the heat insulation layer 3 and the pipeline body 5, and it is filled with ceramic fiber blankets.

[0047]

Example 2

[0048] As Figure 4 shown, in this embodiment, the pipeline body 5 of the raw coal gas transmission pipeline is made of plain carbon steel. The composite sealing and heat insulation lining is composed of a refractory brick support layer 1, a sealing layer 2 cast from refractory castable 22, and a heat insulation layer 3 made of heat-insulating bricks.

[0049] In this embodiment, the high-strength refractory bricks of the refractory brick support layer 1 are high-aluminum bricks. The bricks are joined by a groove and tongue structure. The thickness of the brick layer is 150 mm, and the compressive strength is not less than 40 MPa.

[0050] In this embodiment, the sealing layer 2 is cast from refractory castable 22. The model of the refractory castable 22 is CN-130. The thickness of the sealing layer 2 is 50 mm, and the flexural strength at normal temperature is not less than 4 MPa.

[0051] In this embodiment, the heat insulation layer 3 is made of heat-insulating bricks. The thermal conductivity of the heat-insulating bricks is not greater than 0.3 W / m·K, and the thickness is 113 mm.

[0052] In this embodiment, an axial expansion joint 6 is provided every 1500 mm in both the refractory brick support layer 1 and the sealing layer 2. The width of the axial expansion joint 6 is 7 mm, and it is filled with 7-mm ceramic fiber blankets. The axial expansion joints of the refractory brick support layer 1 are staggered from those of the sealing layer 2 by 100 mm. A circumferential expansion joint 4 with a width of 5 mm is provided between the sealing layer 2 and the heat insulation layer 3, and it is filled with ceramic fiber blankets.

[0053]

Example 3

[0054] As Figure 5 shown, in this embodiment, the pipeline body 5 of the raw coal gas transmission pipeline is made of plain carbon steel. The composite sealing and heat insulation lining is composed of a refractory brick support layer 1, a sealing layer 2 made of heat-resistant stainless steel plate 23, and a heat insulation layer 3 made of heat-insulating bricks.

[0055] In this embodiment, the high-strength refractory bricks of the refractory brick support layer 1 are mullite bricks, and the bricks are connected by tongue-and-groove joints. The thickness of the refractory brick support layer is 110 mm, and the compressive strength is not less than 65 MPa.

[0056] In this embodiment, the sealing layer 2 is composed of several square heat-resistant stainless steel plates 23 with a thickness of 0.3 mm and a side length of 1 m. The heat-resistant stainless steel plates 23 are made of 304 stainless steel plates. The heat-resistant stainless steel plates 23 overlap each other, and the overlap width is 75 mm. The overlapping positions are fixed with stainless steel rivets.

[0057] In this embodiment, the heat insulation layer 3 is made of heat-insulating bricks. The thermal conductivity of the heat-insulating bricks is not greater than 0.15 W / m·K, and the thickness is 113 mm. An axial expansion joint 6 is arranged every 1500 mm in the refractory brick support layer 1. The width of the axial expansion joint 6 is 7 mm, and a 7-mm ceramic fiber blanket is filled inside. A 5-mm-wide circumferential expansion joint 4 is arranged between the sealing layer 2 and the heat insulation layer 3, and a ceramic fiber blanket is filled inside.

[0058] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and should be covered by the protection scope of the present invention.

Claims

1. A raw gas transmission pipeline, characterized in that: It includes a pipeline body and a composite sealing and heat-insulating lining arranged in the pipeline body; the pipeline body is made of carbon steel, and the composite sealing and heat-insulating lining is composed of a refractory brick supporting layer, a sealing layer and a heat-insulating layer arranged in sequence from the inside to the outside.

2. A raw gas transmission pipeline according to claim 1, characterized in that: The refractory brick support layer is a cylindrical structure built by a number of high-strength refractory bricks, with a masonry mortar joint of 2 to 3 mm; two adjacent high-strength refractory bricks are connected by groove and tongue bite; the thickness of the refractory brick support layer is at least 80 mm, and the high-strength refractory bricks are silicon-aluminum refractory bricks with a compressive strength of not less than 20 MPa.

3. A raw gas transmission pipeline according to claim 1, characterized in that: The sealing layer is a cylindrical structure composed of sealing refractory bricks. The circumferential size of the sealing refractory bricks is larger than that of the high-strength refractory bricks. The thickness of the sealing refractory bricks is not less than 50 mm, and the compressive strength is not less than 10 MPa. The sealing refractory bricks and the high-strength refractory bricks of the supporting layer are staggered.

4. A raw gas transmission pipeline according to claim 1, characterized in that: The sealing layer is a cylindrical structure composed of refractory castables, the thickness of the sealing layer is not less than 50 mm, and the room temperature flexural strength of the refractory castables is not less than 2 MPa.

5. The raw gas transmission pipeline according to claim 1, characterized in that: The sealing layer is a cylindrical structure made of heat-resistant stainless steel plates, the thickness of the heat-resistant stainless steel plates is 0.2-2.0 mm, and the overlap width of the heat-resistant stainless steel plates is at least 75 mm.

6. The raw gas transmission pipeline according to claim 1, characterized in that: The heat insulation layer is a cylindrical structure composed of heat insulation bricks or heat insulation castables. The thermal conductivity of the heat insulation bricks or heat insulation castables is less than 0.6W / m·K, and the thickness of the heat insulation layer is not less than 50mm.

7. The raw gas transmission pipeline according to claim 1, characterized in that: The refractory brick support layer and the sealing layer are both provided with an axial expansion joint every 1 to 2 m along the axial direction of the pipeline, and the axial expansion joint is filled with a ceramic fiber blanket; the axial expansion joint of the refractory brick support layer and the axial expansion joint of the sealing layer are spaced more than 50 mm apart and are staggered.

8. The raw gas transmission pipeline according to claim 1, characterized in that: An annular expansion joint is arranged between the insulation layer and the sealing layer of the composite sealing insulation lining, or between the insulation layer and the pipeline body. The width of the annular expansion joint is 5 to 10 mm, and the ceramic fiber blanket is filled in the annular expansion joint.

9. The raw gas transmission pipeline according to claim 1, characterized in that: An outer heat-insulating layer is also provided on the outside of the pipeline body.

Images