A steam backwashing system device matched with a riser heat exchanger

Abstract

The application discloses a rising pipe heat exchanger supporting steam back flushing system device, and relates to the technical field of waste heat recovery and equipment maintenance of coke ovens. The components are sequentially connected by a steam drum, a water supply pipeline, a rising pipe heat exchanger, a return water pipeline, a steam drum, a saturated steam pipeline, a diffusion pipeline, a rising pipe heat exchanger, a superheated steam pipeline, a pipeline stop valve and a plug valve. The back flushing medium is saturated steam produced by the steam drum or provided by an external saturated steam pipeline. The back flushing medium flow is branched from the saturated steam pipeline, introduced into the diffusion pipeline, reversely counter-currently exchanged by the rising pipe heat exchanger to produce superheated steam, merged into the superheated steam pipeline, and the working conditions are changed by the stop valve and the plug valve arranged on the pipeline. The device has the advantages of preventing dry burning and salt water stop supply system continuous operation during equipment maintenance, and the functions of timely maintenance and adjusting the production of saturated steam and superheated steam.

Description

Technical Field

[0001] This utility model belongs to the technical field of coke oven waste heat recovery and equipment maintenance, specifically relating to a steam backflushing system device for a riser heat exchanger. Background Technology

[0002] In recent years, most coke oven raw gas systems, both domestically and internationally, have relied on spraying 70℃-80℃ circulating ammonia water to remove sensible heat, resulting in significant energy waste. Against the backdrop of environmental protection in my country, the technology of utilizing waste heat from coke oven raw gas riser heat exchangers has emerged and gradually gained popularity as an important energy-saving and emission-reduction technology. However, it has not yet achieved widespread adoption. This is because coking enterprises want to obtain high-quality superheated steam, but the temperature of the raw gas at the outlet of the coke oven carbonization chamber is 800℃-1000℃. After the high-temperature raw gas undergoes heat exchange through the riser heat exchanger, if excessive heat exchange causes the raw gas temperature to drop below 450℃, tar will form on the inner wall of the riser heat exchanger. When the condensed tar comes into contact with the open flame in the coke oven, it will produce a visible "black smoke" phenomenon. After cooling, slag will form in the gas, affecting not only the heat exchange efficiency of the riser heat exchanger but also the quality of raw gas in downstream chemical production sections, thus putting pressure on production quality and leading to safety hazards. At the same time, there are also technical constraints on production. Efficiently recovering the waste heat generated during the coking process is one way to reduce coke oven energy consumption, and it is also the direction for establishing a resource-saving and environmentally friendly green coking plant.

[0003] The current waste heat recovery system for coke oven raw gas riser heat exchangers faces the following technical challenges:

[0004] After overhauling the riser heat exchanger and its associated valves, there is a risk of dry burning when the riser heat exchanger is put back into operation. The heat exchanger surface is easily damaged by dry burning due to continuous heating by high-temperature raw coal gas or by excessive thermal stress caused by sudden injection of cold medium, which can lead to cracking of the heat exchanger surface.

[0005] The supply and return water branch pipes of the heat exchanger are prone to blockage in the initial stage of operation, requiring time and effort to temporarily connect and backflush; otherwise, the blockage of the pipes may cause the heat exchanger to burn dry or the system to overpressure.

[0006] The existing system can only produce saturated steam or superheated steam, and cannot adjust the production ratio of saturated steam and superheated steam according to demand.

[0007] The system relies on an external supply of demineralized water, and when the supply of demineralized water is interrupted for a long time, the system must be shut down, resulting in waste of waste heat and production fluctuations.

[0008] Therefore, there is an urgent need for a steam backflushing system device to match the riser heat exchanger in order to solve the above-mentioned technical problems. Utility Model Content

[0009] The object of the present utility model is to provide a steam back-blowing system device matched with an ascension pipe heat exchanger. The present invention aims to solve the problems of dry burning of the ascension pipe heat exchanger, forced shutdown, pipeline blockage, and adjustment of the output steam quality ratio in the existing waste heat utilization system of a coke oven crude gas ascension pipe heat exchanger, and provides a steam back-blowing system device matched with an ascension pipe heat exchanger.

[0010] In order to achieve the above technical objective, the technical solution of the steam back-blowing system device matched with an ascension pipe heat exchanger is as follows:

[0011] A steam back-blowing system device matched with an ascension pipe heat exchanger, comprising connection relationships formed sequentially by components including a steam drum, a water supply pipe, an ascension pipe heat exchanger, a water return pipe, a steam drum, a saturated steam pipe, a discharge pipe, an ascension pipe heat exchanger, a superheated steam pipe, and a stop valve and a plug cock valve arranged on the pipes; in the steam back-blowing system device matched with an ascension pipe heat exchanger, the back-blowing medium is saturated steam produced by the steam drum or provided by an external saturated steam pipeline, the flow path of the back-blowing medium is that the branch of the saturated steam pipe merges into the discharge pipe, passes through the ascension pipe heat exchanger for reverse convective heat transfer to produce superheated steam, which then converges into the superheated steam pipe, and working conditions are changed through the stop valve and the plug cock valve arranged on the pipelines.

[0012] Further defined, a stop valve and a plug cock valve are arranged on the discharge pipe for switching between the discharge function and the saturated steam back-blowing function.

[0013] Further defined, a stop valve and a plug cock valve are arranged on the water return pipe for switching between the discharge function and the return water delivery function.

[0014] Further defined, a stop valve and a plug cock valve are arranged on the water supply pipe for switching between the water supply function and the superheated steam delivery function.

[0015] The beneficial effects that can be produced by the above steam back-blowing system device matched with an ascension pipe heat exchanger include but are not limited to:

[0016] The dry burning risk after the maintenance of the ascension pipe heat exchanger and matched valves and their re-commissioning can be solved through technical optimization, which avoids dry burning damage to the heat exchange surface of the heat exchanger caused by continuous heating of high-temperature crude gas, and also avoids the problem of heat exchange surface cracking caused by excessive thermal stress of the heat exchanger induced by sudden injection of cold medium. The invention realizes two-way blockage removal during discharge in the initial commissioning stage and back-blowing, and the slow back-blowing effect of saturated steam to prevent dry burning before re-commissioning after the maintenance of the ascension pipe heat exchanger and valves.

[0017] A technical breakthrough is achieved aiming at the problem that the water supply and return branch pipes of the heat exchanger are easily blocked in the initial commissioning stage, it is no longer necessary to spend time and effort on temporary connection for back-blowing, and dry burning of the heat exchanger or system overpressure caused by pipeline blockage is avoided. The normal operation of the waste heat utilization system of the coke oven crude gas ascension pipe heat exchanger is realized, and the temperature of the ascension pipe heat exchanger is adjusted through discharge.

[0018] The system is provided with a regulating function, which can adjust the yield ratio of saturated steam and superheated steam according to actual requirements, so that the heat exchanger is no longer limited to only producing steam with a single type of parameter. It realizes the normal operation of the waste heat utilization system of the coke oven raw gas ascension pipe heat exchanger and the function of adjusting the yield ratio of saturated steam and superheated steam.

[0019] Aiming at getting rid of the dependence on external desalinated water supply, in an emergency state, saturated steam is used to replace steam drum feed water for heat exchange through the ascension pipe heat exchanger, so that the waste heat utilization system of the coke oven raw gas ascension pipe heat exchanger can still continue to operate normally when the external desalinated water supply is stopped. The problem that the system is forced to shut down when desalinated water supply is stopped for a long time is completely solved, and waste heat waste and production fluctuation are avoided. The continuous and normal operation of the waste heat utilization system of the coke oven raw gas ascension pipe heat exchanger is realized when the external desalinated water supply is stopped. Description of Drawings

[0020] Figure 1 is a system diagram of a steam back-blowing system device matched with an ascension pipe heat exchanger of the utility model;

[0021] Figure 2 is a top view of a steam back-blowing system device matched with an ascension pipe heat exchanger of the utility model;

[0022] Figure 3 is a side view of a steam back-blowing system device matched with an ascension pipe heat exchanger of the utility model;

[0023] In the figure, the correspondence between the reference numerals and the component names is: 1. Steam drum; 2. Ascension pipe heat exchanger; 3. Water supply pipeline; 4. Return water pipeline; 5. Bleeding pipeline; 6. Saturated steam pipeline; 7. Superheated steam pipeline; 8. Stop valve; 9. Plug cock. Detailed Description of the Embodiment

[0024] In order to more clearly illustrate the overall concept of the present application, the following detailed description is given by way of example with reference to the accompanying drawings of the description.

[0025] In order to more clearly understand the above objects, features and advantages of the present application, the present application is further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0026] Many specific details are set forth in the following description to facilitate a full understanding of the present application. However, the present application can also be implemented in other ways different from those described herein. Therefore, the protection scope of the present application is not limited by the specific embodiments disclosed below.

[0027] Furthermore, it should be understood in the description of this application that the terms “center,” “upper,” “lower,” “front,” “rear,” “left,” “right,” “vertical,” “horizontal,” “top,” “bottom,” “inner,” “outer,” “axial,” “radial,” and “circumferential” indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0028] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0029] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0030] In this application, unless otherwise expressly specified and limited, the "above" or "below" of a second feature can mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. In the description of this specification, the references to the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples" indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described can be combined in any suitable manner in one or more embodiments or examples.

[0031] This invention provides a steam backflushing system device for a riser heat exchanger, which is used to solve the technical pain points of coke oven waste heat recovery and equipment maintenance, while ensuring normal coke oven production. The structure and usage of the steam backflushing system device for a riser heat exchanger of this application will be described in detail below with reference to the accompanying drawings.

[0032] See Figure 1The equipment consists of, in sequence, a steam drum 1, a water supply pipe 3, a riser heat exchanger 2, a return water pipe 4, a steam drum 1, a saturated steam pipe 6, a vent pipe 5, a riser heat exchanger 2, a superheated steam pipe 7, and shut-off valves 8 and plug valves 9 connected to the pipes. The backflush medium is saturated steam produced by the steam drum 1 or supplied by the external saturated steam pipe 6. The backflush medium flows from a branch of the saturated steam pipe 6 into the vent pipe 5, undergoes reverse convection heat exchange through the riser heat exchanger 2 to produce superheated steam, which then flows into the superheated steam pipe 7. The operating conditions are changed by the shut-off valves 8 and plug valves 9 installed on the pipeline.

[0033] In one implementation, a shut-off valve 8 and a plug valve 9 are specifically installed on the vent pipe 5. These are used to switch between venting and saturated steam backflushing functions, enabling bidirectional clearing of blockages during initial commissioning and slow saturated steam backflushing to cool and prevent dry burning before restarting the riser heat exchanger 2 and other equipment after maintenance. During initial commissioning, the shut-off valve 8 and plug valve 9 on the vent pipe 5 are opened for forward drainage, while the shut-off valves 8 and plug valve 9 on the saturated steam pipe 6 and superheated steam pipe 7 are opened for reverse drainage. Before restarting the riser heat exchanger 2 and other equipment after maintenance, the shut-off valves 8 and plug valve 9 on the saturated steam pipe 6 and superheated steam pipe 7 are opened to allow saturated steam to slowly backflush and cool the riser heat exchanger 2.

[0034] Specifically, a shut-off valve 8 and a stop valve 9 are installed on the return water pipe 4. These are used to switch between venting and return water delivery functions, ensuring the normal operation of the coke oven gas riser heat exchanger waste heat utilization system. The temperature of the riser heat exchanger 2 is regulated by the shut-off valve 8 and the stop valve 9 on the venting pipe 5. When the coke oven gas riser heat exchanger waste heat utilization system is operating normally, the shut-off valves 8 and 9 on the supply water pipe 3 and the return water pipe 4 need to be opened to allow heat exchange through the riser heat exchanger 2. When the temperature of the riser heat exchanger 2 is too high, the shut-off valves 8 and 9 on the venting pipe 5 need to be opened to release pressure and increase the flow rate for cooling.

[0035] Specifically, a shut-off valve 8 and a stop valve 9 are installed on the water supply pipeline 3. These are used to switch between water supply and superheated steam delivery functions, ensuring the normal operation of the coke oven raw gas riser heat exchanger waste heat utilization system and regulating the ratio of saturated steam and superheated steam production. When the coke oven raw gas riser heat exchanger waste heat utilization system is operating normally, the shut-off valve 8 and stop valve 9 on the water supply pipeline 3 and return water pipeline 4 need to be opened to allow heat exchange through the riser heat exchanger 2. When it is necessary to increase the superheated steam production and reduce the saturated steam production, the shut-off valve 8 and stop valve 9 on the water supply pipeline 3 and return water pipeline 4 need to be closed to stop the saturated steam from being produced through the riser heat exchanger 2, and the shut-off valve 8 and stop valve 9 on the saturated steam pipeline 6 and superheated steam pipeline 7 need to be opened to allow the saturated steam to be produced through the riser heat exchanger 2.

[0036] Working principle:

[0037] See Figure 1 , Figure 2 and Figure 3 A steam backflushing system for a riser heat exchanger consists of: a steam drum 1, a riser heat exchanger 2, a water supply pipe 3, a return water pipe 4, a vent pipe 5, a low-pressure steam pipe 6, a superheated steam pipe 7, and shut-off valves 8 and plug valves 9 connecting various supporting equipment. The backflushing medium is saturated steam produced by the steam drum 1 or provided by the external saturated steam pipe 6. The backflushing medium flows from the saturated steam pipe 6 into the vent pipe 5, through the riser heat exchanger 2, reverse convection heat exchange to produce superheated steam, which then flows into the superheated steam pipe 7. The operating conditions are changed by the shut-off valves 8 and plug valves 9 installed on the pipeline.

[0038] This riser heat exchanger is equipped with a steam backflushing system, which has the advantages of preventing dry burning during equipment maintenance and ensuring continuous operation of the demineralized water supply system. It also has the function of timely maintenance and adjustment of the ratio of saturated steam and superheated steam production. It can solve the problems of dry burning of riser heat exchangers, forced shutdown, pipeline blockage, and adjustment of the quality ratio of produced steam. It is suitable for coke oven waste heat recovery system environments.

[0039] Under the same conditions, the heat transfer efficiency (heat transfer per unit area) of the riser heat exchanger paired with the steam backflushing system is 20% to 50% higher than that of the co-current system (the specific efficiency depends on the fluid properties and temperature difference). See [link / reference]. Figure 2 The riser heat exchanger 2 is generally divided into left and right types with mirrored settings. The left and right directions are determined by the position of the cylinder of the gas collecting pipe flap valve when standing on the center line of the coke oven. Note the installation position of the riser.

[0040] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to interchangeably. Each embodiment focuses on describing the differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments.

[0041] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A steam backflushing system for a riser heat exchanger, characterized in that, The device comprises, in sequence, a steam drum, a water supply pipeline, a riser heat exchanger, a return water pipeline, a steam drum, a saturated steam pipeline, a venting pipeline, a riser heat exchanger, a superheated steam pipeline, and shut-off valves and plug valves connected to the pipelines. The riser heat exchanger is equipped with a steam backflushing system. The backflushing medium is saturated steam produced by the steam drum or supplied by an external saturated steam pipeline. The backflushing medium flows from a branch of the saturated steam pipeline into the venting pipeline, through the riser heat exchanger for reverse convection heat exchange to produce superheated steam, which then flows into the superheated steam pipeline. The operating conditions are changed by shut-off valves and plug valves installed on the pipelines.

2. The steam backflushing system device for a riser heat exchanger according to claim 1, characterized in that, The venting pipe is equipped with a shut-off valve and a plug valve.

3. The steam backflushing system device for a riser heat exchanger according to claim 1, characterized in that, The return water pipe is equipped with a shut-off valve and a stop valve.

4. The steam backflushing system device for a riser heat exchanger according to claim 1, characterized in that, The water supply pipeline is equipped with a shut-off valve and a stop valve.

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