JP2021055988A - Raw coke oven gas sensible heat exchanger and mounting structure thereof - Google Patents

Abstract

To provide a raw coke oven gas sensible heat exchanger that recovers waste heat of raw coke oven gas effectively to improve the energy saving of a coke oven, and is light-weight and convenient for exchange, and a mounting structure thereof.SOLUTION: A sensible heat exchanger comprises a heat exchanger shell 3, a superheated steam exhaust pipe 2 is arranged at the top of the heat exchanger shell, a water absorption pipe 6 is arranged at the bottom of the heat exchanger shell, and a gas-moisture separator 4 is arranged inside the heat exchanger shell, so that it is possible to reduce carbon emissions in a manufacturing process and economically recover sensible heat.SELECTED DRAWING: Figure 1

Description

The present invention relates to the fields of coking and coal chemical equipment, specifically, a coke oven gas heat exchanger and its mounting structure.

Coking in a coke oven is the primary method of producing coke in the coking unit of the steel and coal chemical businesses. Due to the large amount of heat energy conversion and release in coke production in a coke oven, there are four forms: red heat coke, raw coke oven gas, coke oven flue gas exhaust heat, and coke oven heat radiation. Coke (exhaust heat) resources are mainly generated. Among them, the sensible heat of the raw coke oven gas accounts for about 35% of the total heat resources from the production emissions of the coke oven. During coking in the coke oven, the temperature of the crude gas in the coke oven riser is as high as 650 ° C to 850 ° C and contains a large amount of sensible heat. To ensure equipment safety and a smooth manufacturing process, spray ammonia water to quench medium and high temperature crude gas, i.e. spray circulating ammonia water onto bridge tubing and gas collectors for direct contact with crude gas. It is common to quench the crude gas to 80 ° C. to 85 ° C. The cooled crude gas is indirectly cooled to room temperature by the cooling water of the primary cooler. This process not only wastes a large amount of sensible heat of crude gas, but also consumes a large amount of ammonia water and industrial cooling water, resulting in large-scale sewage discharge and power consumption. When the temperature of the crude gas drops below about 450 ° C due to the complex composition of the medium and high temperature crude gas from the coke oven and the periodic changes in flow rate and temperature, a large amount of tar components settle and the flow path tube It closes and affects smooth production. Recovery of sensible heat of crude gas has always been a technical challenge in the industry. Therefore, the recovery of sensible heat from raw coke oven gas has always been one of the studies focused on energy saving and emission reduction in the coking industry.

Currently, several coking plants and research institutes in China are researching sensible heat recovery technology and equipment for coke oven gas, in which the outer surface of the riser cylinder is jacketed and coiled. Heat recovery techniques and equipment are commonly adopted, which are bottles of reduced heat exchange efficiency due to the constraints of two-stage / two-layer heat transfer between cylinders and tubes, which are essentially integrated double-walled structures. There is a bottleneck challenge, which directly leads to poor steam quality. The two types of equipment are bulky, consume large amounts of material, and require replacement of the original riser, which has a total height of several meters. As a result, the unit price of the riser reaches about 150,000 to 180,000 yuan, so that the device is expensive and replacement is inconvenient. In particular, the jacket-type sensible heat recovery device stores water in the cavity. When cavities swell, crack and leak, large amounts of water pose a serious safety hazard to coke oven equipment.

The patent application entitled "Finned raw heat recovery device" of Patent Document 1 provides sensible heat recovery and a utilization device which is a jacket-type integrated structure essentially composed of an outer cylinder and an inner cylinder. provide. The heat exchange region is increased by including fins that can adequately improve sensible heat recovery efficiency. However, the device proposed in that application is still a jacket structure and cannot essentially solve the problem of cavities cracking and leakage.

In the patent application of Patent Document 2 entitled "Sensible heat recovery of raw coke of gas riser", a spiral coil and a molten salt conductive medium are used to solve the problems of equipment leakage and deterioration of the conductive medium. Is proposing. Due to the use of a spiral coil structure in the riser, the recovery device provided in the application increases the flow resistance of the crude gas, easily causing irregular airflow problems, and the crude gas coke on the spiral coil. As a result, problems such as corrosion of the pipe and a sharp decrease in heat exchange efficiency occur.

"Method and emission for exporting body-in temperature-in temperature expansion decoking heat pipe of riser waste heat" Innovatively adopts a unit sensible heat recovery device that has the advantage of low cost. However, the most serious problem is that the device can only produce low values of saturated steam because the internal hollow structure does not separate steam and water.

Application No. 200821349087.3. Application number 201420811623.2. Application number 201410309838.9

The technical problem to be solved in the present invention is to provide a lightweight and convenient replacement raw coke oven gas heat exchanger and its mounting structure, thereby effectively recovering the exhaust heat of the raw coke oven gas. It is to clearly improve the energy saving level of the coke oven.

A technical solution for solving the technical problem of the present invention is a raw coke furnace gas manifest heat exchanger including a heat exchanger shell (heat exchanger container), and the superheated steam discharge pipe is a heat exchanger shell. Located at the top, the water absorption pipe is located at the bottom of the heat exchanger shell, and the air-water separator is located within the heat exchanger shell.

Further, a diffuser is arranged at the outlet of the water absorption pipe.
In addition, the heat exchanger shell has a cylindrical hollow structure.
In addition, the head of the lower shell of the heat exchanger shell is hemispherical, oval, or conical.
Further, the thickness of the tube wall of the heat exchanger shell is 2 mm to 8 mm.

Further, the gas-water separator divides the heat exchanger shell into an upper region and a lower region, the lower region being a gas-liquid separation region and the upper region being a steam superheat region.

In addition, the outer wall layer of the heat exchanger shell is provided with a high thermal conductivity anti-adhesion material.

Further, a temperature detection element or pressure detection element is arranged in the heat exchanger shell, and the temperature detection element or pressure detection element communicates with the end of the water supply flow rate control device.

In addition, the mounting structure of the raw coke furnace gas heat exchanger further includes a riser, the heat exchanger shell is placed in the riser tube of the riser, and the water absorption tube and superheated steam discharge tube of the heat exchanger shell are the walls of the riser. It passes through the hole and extends to the outside of the riser.

Further, an expansion pipe joint is arranged between the water absorption pipe, the superheated steam discharge pipe and the hole in the wall of the riser, and the expansion pipe joint is filled with refractory wool.

The beneficial effects of the present invention are as follows. The present invention combines a built-in design with a multi-state and phase-changing heat exchange structure to replenish a brackish water separator and adequately solve the problem of sensible heat exchange of raw coke oven gas. On the other hand, due to the lightweight and simple structure of the present invention, the unit price of the device can be significantly controlled. The apparatus and method of the present invention can realize economical and effective recovery of sensible heat of raw coke oven gas, which is very important in energy saving in the steel metallurgy business or the coking field. The use of the devices and methods of the present invention is very important in facilitating advances in energy conservation technology in coking units in the steel and coal chemical businesses, reducing carbon emissions in the manufacturing process, and achieving economical recovery of sensible heat. Is important to. The present invention is particularly applicable to the sensible heat exchange process of raw coke oven gas.

It is a structural drawing of this invention.

The numbers in the figure are superheated steam discharge port 1, superheated steam discharge pipe 2, heat exchanger shell 3, steam separator 4, diffuser 5, water absorption pipe 6, water absorption port 7, hanger 8, riser 9, and riser. Represents tube 91.

The present invention will be further described in combination with drawings and examples.
The raw coke oven gas heat exchanger shown in FIG. 1 includes a heat exchanger shell (3), a superheated steam discharge pipe (2) is arranged at the top of the heat exchanger shell (3), and a water absorption pipe (6). ) Is located at the bottom of the heat exchanger shell (3), and the air-water separator (4) is located inside the heat exchanger shell (3).

In actual application, the mounting structure of the raw coke furnace gas heat exchanger further includes a riser (9) in the mounting structure, as shown in FIG. 1, and the raw coke furnace gas heat exchanger is mounted on the riser (9). It can be arranged vertically, the heat exchanger shell (3) is arranged in the riser pipe (91) of the riser (9), and the water absorption pipe (6) and the superheated steam discharge pipe (2) of the heat exchanger shell (3) are arranged. It passes through a hole in the wall of the riser (9) and extends to the outside of the riser (9). It is generally preferred to place the hanger 8 at the top of the heat exchanger shell 3 to facilitate the attachment and detachment of the device. The present invention can also use multiple heat exchanger shells 3 in parallel or in series as desired, thus significantly improving heat exchange efficiency. Since the device has a double support structure consisting of a superheated steam discharge pipe (2) and a water absorption pipe (6), the superheated steam discharge pipe (2) and the water absorption pipe (6) are respectively during machining and assembly. It is preferred to bend towards the heat exchanger shell (3) to allow thermal expansion of the heat exchanger shell.

Based on the flow characteristics of the raw coke oven gas in the riser (9), the present invention skillfully combines the built-in design with a multi-cavity, multi-state and phase change heat exchange structure to obtain the desired effect. In practical applications, superheated steam of various pressures and temperatures can be generated as needed, and the outlet temperature of the raw coke oven gas is controlled within the expected temperature range or above 450 ° C, where a large amount of tar precipitates from the crude gas. it can. Since this is higher than the critical precipitation temperature of tar, it is possible to completely eliminate equipment adhesion accidents. The present invention solves the problems of low steam quality, high price, easy coking of heat exchangers, difficult installation, and high cost of replacement and maintenance, and guarantees the normal operation of the coke oven in principle. Effectively recovers the exhaust heat of coke oven gas. As a result, the energy saving level of the coke oven can be significantly improved. An expansion joint is placed between the water absorption pipe (6), the superheated steam discharge pipe (2), and the hole in the wall of the riser (9) to ensure the structural stability and airtightness required during installation. You can choose solutions such as filling expansion fittings with fire resistant wool.

In practical use, a solution such as arranging a diffuser (5) at the water outlet of the water absorption pipe (6) in order to uniformly supply water when the water absorption pipe (6) diffuses water into the cavity can be selected. The heat exchange medium can be selected from desalted water, degassed water, unsaturated water and saturated steam. The heat exchange medium is introduced into the water absorption pipe (6) via a water inlet (7) equipped with a flow control switch, and is evenly divided into a plurality of turbulent flows via a diffuser (5) for heating or heat exchange. Therefore, it is sprayed on the inner wall of the cavity at the lower end of the heat exchanger shell (3) to form a water-water mixture. Subsequently, the brackish water mixture is passed through a brackish water separator (4) for brackish water separation to obtain saturated steam. Saturated steam continues to flow upward, endothermic, and finally superheated steam is generated. Superheated steam flows out of the superheated steam outlet (2) and the superheated steam outlet (1) and enters the next steam tube network for use in the process. The apparatus thus completes the recovery of the sensible heat of the crude gas in the coke oven riser.

In order to achieve better heat exchange efficiency, the heat exchanger shell (3) is preferably a cylindrical hollow structure. In addition, the top of the bottom shell of the heat exchanger shell (3) is preferably hemispherical, oval or conical. The thickness of the tube wall of the heat exchanger shell (3) is preferably 2 mm to 8 mm.

To achieve the corresponding heat exchange effect, the steam separator (4) divides the heat exchanger shell (3) into an upper region and a lower region, the lower region is the gas-liquid separation region and the upper region is. Solutions such as brackish water regions are preferred. As shown in FIG. 1, the brackish water separator (4) incorporated in the cavity of the heat exchanger shell (3) covers the entire cavity of the heat exchanger shell (3) in the upper and lower multi-cavity / multi-state regions. Can be divided into and. The lower region provides gas-liquid separation and the upper region provides steam overheating.

In order to ensure stable operation of the heat exchanger shell (3), the wall layer of the heat exchanger shell (3) is locally thickened, or the outer wall layer of the heat exchanger shell (3) has a high thermal conductivity. It is preferable to provide an anti-adhesion material.

In order to match the water supply with the progress of heat exchange in the heat exchanger shell (3), a temperature detection element or pressure detection element is placed in the heat exchanger shell (3) and the temperature detection element or pressure detection element is supplied with water. You can choose a solution, such as communicating with the end of the flow control device.

Example (Embodiment 1)
A single heat exchanger shell (3) having a thickness of 3 mm in the tube wall of the heat exchanger shell (heat exchange container) and a hemispherical head portion of the lower shell is placed in the riser (9), and the riser is used. (9) The temperature of the upper measurement point is about 850 ° C. for a certain period of time. Unsaturated water under pressure is used as the heat exchange medium, and the heat exchange medium is delivered from the water absorption tube to the heat exchanger under a specific pressure. The temperature of the superheated steam at the outlet of the device can reach 241 ° C, and the temperature drop at the measurement point is about 100 ° C, which produces superheated steam while keeping the temperature of the crude gas after heat exchange above 460 ° C. To realize.

(Embodiment 2)
A high thermal conductivity material is sprayed onto the outer walls of two heat exchanger shells (3) having the same structure and a tube wall thickness of 3.5 mm and placed parallel to the same riser (9). The head of the lower shell is an ellipsoid. The temperature of the upper measurement point of the riser (9) is about 780 ° C. for a certain period of time. The degassed water is used as a heat exchange medium and delivered to two heat exchangers through a water absorption tube under specific pressure. The superheated steam temperature at the outlets of the two devices can reach 183 ° C and the temperature drop at the measurement point is about 209 ° C, which keeps the crude gas temperature after heat exchange above 460 ° C. Achieve increased production of superheated steam.

From the above examples, it can be concluded that the present invention can significantly reduce carbon emissions in the manufacturing process and significantly improve sensible heat recovery efficiency. This is very important in energy saving in the steel metallurgy business or the coking field and broadens the prospect of sales promotion in the market.

Claims (10)

A raw coke furnace gas heat exchanger, characterized in that it includes a heat exchanger shell (3), with a superheated steam discharge pipe (2) located at the top of the heat exchanger shell (3) to absorb water. A raw coke furnace gas microheat exchanger in which a tube (6) is located at the bottom of the heat exchanger shell (3) and an air-water separator (4) is located in the heat exchanger shell (3). The raw coke oven gas heat exchanger according to claim 1, wherein the diffuser (5) is arranged at the water outlet of the water absorption pipe (6). The raw coke oven gas sensible heat exchanger according to claim 1 or 2, wherein the heat exchanger shell (3) has a cylindrical hollow structure. The raw coke oven gas sensible heat exchanger according to claim 3, wherein the front portion of the bottom shell of the heat exchanger shell (3) has a hemispherical shape, an elliptical shape, or a conical shape. The raw coke oven gas sensible heat exchanger according to claim 1 or 2, wherein the tube wall thickness of the heat exchanger shell (3) is 2 mm to 8 mm. The gas-water separator (4) divides the heat exchanger shell (3) into an upper region and a lower region, the lower region is a gas-liquid separation region, and the upper region is a steam superheat region. The raw coke oven gas sensible heat exchanger according to claim 1 or 2, wherein the raw coke oven gas sensible heat exchanger is characterized. The raw coke oven gas sensible heat exchanger according to claim 1 or 2, wherein an adhesion-preventing material having a high thermal conductivity is provided on the outer wall of the heat exchanger shell (3). A claim, wherein the temperature detection element or the pressure detection element is arranged in the heat exchanger shell (3), and the temperature detection element or the pressure detection element communicates with an end portion of the water supply flow control device. The raw coke oven gas sensible heat exchanger according to 1 or 2. A mounting structure for a raw coke oven gas heat exchanger formed by using the raw coke oven gas heat exchanger according to claim 1, further comprising a riser (9), and the heat exchange. The vessel shell (3) is arranged in the riser pipe (91) of the riser (9), and the water absorption pipe (6) and the superheated steam discharge pipe (2) on the heat exchanger shell (3) are the same. A mounting structure that extends through a hole in the wall of the riser (9) to the outside of the riser (9). The mounting structure for the raw coke oven gas heat exchanger according to claim 1 or 2, wherein the water absorption pipe (6), the superheated steam discharge pipe (2), and the hole in the wall of the riser (9). A mounting structure characterized in that a telescopic pipe joint is arranged between the two, and the telescopic pipe joint is filled with refractory wool.

Images