WO2023071418A1

WO2023071418A1 - Vaporization cooling system and method with control over high-loop enhanced steam-water separation

Info

Publication number: WO2023071418A1
Application number: PCT/CN2022/112400
Authority: WO
Inventors: 李嘉麒; 代黎; 孙薇
Original assignee: 中冶南方工程技术有限公司
Priority date: 2021-10-28
Filing date: 2022-08-15
Publication date: 2023-05-04
Also published as: CN114034029A

Abstract

The present invention relates to the technical field of iron and steel metallurgy, and in particular to a vaporization cooling system and method with control over high-loop enhanced steam-water separation. The system comprises a steam drum body, and a water supplementing system and a steam output pipeline, which are connected to the steam drum body; and further comprises a forced circulation system and a natural circulation system, wherein the forced circulation system comprises a forced circulation pump and a first heat exchanger, which are successively connected by means of a pipeline, an input end and an output end of the forced circulation system are connected to the steam drum body to form a forced circulation loop, and water in the steam drum body passes through the forced circulation system and then enters the steam drum body from a high position; and the natural circulation system comprises a second heat exchanger, and the second heat exchanger and the steam drum body are connected by means of a pipeline to form a loop. By means of the present invention, early-stage testing and late-stage user maintenance is made convenient, the water discharge amount is reduced, and a steam-water separation effect of backwater in the vaporization cooling system is also enhanced, so that the overall steam-water separation effect is improved; moreover, flow dynamic adjustment is achieved by means of control, so that the overall performance is improved.

Description

An evaporative cooling system and its method with a controlled high-loop enhanced steam-water separation

technical field

The invention relates to the technical field of iron and steel metallurgy, in particular to an evaporative cooling system and a method thereof with a controlled high-loop enhanced steam-water separation.

Background technique

The energy consumption of iron and steel enterprises accounts for nearly 10% in my country. At the same time, there is still a lot of gap between iron and steel enterprises and developed countries in the utilization rate of waste heat at this stage. One of the important ways to make iron and steel production efficient and green; at present, there are two main cooling methods for waste heat boilers, one is open circuit or direct cooling with circulating water, and the other is vaporization cooling. Compared with direct water cooling, the vaporization cooling system produces Steam can be incorporated into the steam pipe network in the factory area for power generation, power, heating, etc., with higher energy utilization.

The waste heat boiler vaporization cooling system is to change the traditional flue water cooling method into vaporization cooling method. Different heat exchangers are set in different temperature sections of the flue gas, so that the heat carried by the flue gas can be recovered efficiently. For large converters , The electric furnace has a good heat collection effect.

During the use of the existing waste heat boiler evaporative cooling system, it was found that since the return water section of the steam drum of the existing waste heat boiler evaporative cooling system is basically located in the middle and below, a large amount of water will be released when the machine is shut down for maintenance and testing , causing great waste. At the same time, during the working process of the waste heat boiler vaporization cooling system, since the high water level section will be basically close to or not pass through the return water pipeline, there is no enhanced effect on the separation of steam and water.

Contents of the invention

The object of the present invention is to provide a vaporization cooling system and its method with a control high circuit to strengthen the separation of steam and water, which improves the height of the return water circulation inlet, avoids the return water in the maintenance process, and solves the problem of the current system in the maintenance process. In the case of excessive water discharge, the steam-water separation is strengthened, and the overall energy utilization is improved; at the same time, in order to ensure the stability of the liquid level inside the steam drum body, an auxiliary control method is proposed to ensure the stable operation of the system.

On the one hand, the present invention provides an evaporative cooling system with a controlled high-loop enhanced steam-water separation, including a steam drum body, a water replenishment system and a steam outlet pipeline, and the water replenishment system is connected to the steam drum body for supplying The steam drum body replenishes water, the steam outlet pipeline is connected with the steam drum body, and the vaporization cooling system also includes a forced circulation system and a natural circulation system; wherein,

The forced circulation system includes a forced circulation pump and a first heat exchanger connected in sequence through pipelines. The input and output ends of the forced circulation system are connected to the steam drum body to form a forced circulation loop. The steam drum body The water inside enters the steam drum body from a high position after passing through the forced circulation system;

The natural circulation system includes a second heat exchanger, and the second heat exchanger is connected to the steam drum body through pipelines to form a natural circulation loop.

Further, the forced circulation system also includes a forced circulation outlet pipeline, a forced circulation intermediate pipeline, and a forced circulation inlet pipeline. Water is driven from the steam drum body and flows through the forced circulation outlet pipeline, forced circulation Circulation pump, forced circulation intermediate pipeline, first heat exchanger, forced circulation inlet pipeline, and return to the steam drum body; the forced circulation inlet pipeline is arranged on the upper side of the steam drum body, and the The forced circulation outlet pipeline is connected with the lower side of the steam drum body.

Further, a high-pressure circulation outlet valve and a high-pressure circulation inlet valve are respectively arranged on the forced circulation outlet pipeline and the forced circulation inlet pipeline.

Further, the forced circulation inlet pipeline and the steam outlet pipeline are respectively arranged on both sides of the steam drum body.

Further, the natural circulation system also includes a natural circulation outlet pipeline and a natural circulation inlet pipeline, and water flows through the natural circulation outlet pipeline, the second heat exchanger, and the natural circulation inlet sequentially from the steam drum body. pipeline, and return to the steam drum body; the natural circulation outlet pipeline and the natural circulation inlet pipeline are connected with the lower side of the steam drum body.

Further, a natural circulation outlet valve and a natural circulation inlet valve are respectively arranged on the natural circulation outlet pipeline and the natural circulation inlet pipeline.

Further, an intermediate partition is also arranged in the steam drum body.

Further, a high water level gauge and a low water level gauge for detecting the liquid level are also arranged in the steam drum body.

Further, the water replenishment system includes a water replenishment pump, and a replenishment water inlet pipeline connected to the steam drum body.

On the other hand, the present invention also provides a steam-water cooling method with controlled high-loop enhanced steam-water separation, comprising the following steps:

S1: replenish water to the steam drum body by the water supply system to ensure that the liquid level in the steam drum body is normal;

S2: Open the forced circulation system, the water in the steam drum body enters the first heat exchanger by the forced circulation pump to exchange heat, and the steam-water mixture formed after returning to the steam drum body, and steam-water separation is carried out, wherein , the water of the forced circulation system enters the steam drum body from the upper side of the steam drum body;

S3: Open the natural circulation system, the steam-water mixture formed after the water in the steam drum body enters the second heat exchanger for heat exchange flows back into the steam drum body, and separates the steam-water.

The steam-water cooling system of the present invention includes a forced circulation system and a natural circulation system forming a circulation loop with the steam drum body. The forced circulation system drives the internal liquid circulation through a forced circulation pump, and drives water from the steam drum body to the first heat exchanger for After heat exchange, it enters the steam drum body from the high position to separate the steam and water. After the water flows through the first heat exchanger, it enters the steam drum body from the upper side of the steam drum body; the natural circulation system is driven by the liquid level difference and temperature difference. The internal liquid circulates, and the water flows from the steam drum body to the second heat exchanger for heat exchange. The water after the temperature rises is driven back into the steam drum body due to the temperature difference for steam-water separation.

Compared with the prior art, the present invention has the following beneficial effects due to the adoption of the above technical scheme:

1) The evaporative cooling system and method provided by the present invention with a high control circuit to strengthen the steam-water separation, by improving the position of the return water interface of the forced circulation system, the effect of the steam-water separation is strengthened, and the replacement of the steam-water cooling system is used to a greater extent. The heat improves the working efficiency of the vaporization cooling system, which has very positive significance for the practical application of the metallurgical industry;

2) The evaporative cooling system and the method thereof provided by the present invention can greatly reduce the amount of water released during the test and commissioning process through the high water level return water, thus shortening the overall period of the test and commissioning process, While saving water resources, it makes the commissioning and maintenance of the vaporization cooling system more convenient;

3) The evaporative cooling system and the method thereof provided by the present invention are provided with a control high-loop enhanced steam-water separation, valves are arranged on each pipeline of the forced circulation system and the natural circulation system, and the flow dynamics during debugging, testing, and normal operation are realized. Adjustment, while ensuring the installability of the system, can also improve the matching degree between the various devices of the vaporization cooling system during the working process, ensure the heat transfer capacity of each heat exchanger, and improve the overall working efficiency.

Description of drawings

Fig. 1 is a structural schematic diagram of an evaporative cooling system with a control high circuit and enhanced steam-water separation in the present invention.

1-Drum body; 2-Natural circulation outlet pipeline; 3-Natural circulation inlet pipeline; 4-Supply water inlet pipeline; 5-Supplement water source pipeline; 6-Forced circulation outlet pipeline; 7-Forced circulation intermediate pipe 8-forced circulation inlet pipeline; 9-steam outlet pipeline; 10-high water level gauge; 11-low water level gauge; 12-first heat exchanger; 13-second heat exchanger; 14 -forced circulation pump; 15-; 16-high-pressure circulation outlet valve; 17-high-pressure circulation inlet valve; 18-natural circulation outlet valve; 19-natural circulation inlet valve; 20-middle partition.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some of the embodiments of the present invention, not all of them. Based on The embodiments of the present invention and all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention. In the drawings, the size and relative size of certain parts may be exaggerated for clarity.

In the description of the present invention, unless otherwise clearly stipulated and limited, the terms "connected" and "connected" should be interpreted in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral body; it can be a mechanical The connection can also be an electrical connection; it can be a direct connection or an indirect connection through an intermediary, it can be the internal communication of two elements or the interaction relationship between two elements, and for those of ordinary skill in the art, it can be The specific meanings of the above terms in the present invention should be understood in detail.

In the description of the present invention, the terms "upper", "lower", "left", "right", "front", "back" and other orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings, and are only In order to facilitate description and simplify operation, it does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and thus should not be construed as limiting the present invention.

In addition, in the description of the present invention, the terms "first" and "second" are only used for distinction in description.

As shown in the accompanying drawing 1 of the description, on the one hand, the present invention provides a kind of vaporization cooling system with control high-loop enhanced steam-water separation, including a steam drum body 1, a water replenishment system and a steam outlet pipeline 9, the water replenishment system and the described The steam drum body 1 is connected to replenish water to the steam drum body 1, the steam outlet pipeline 9 is connected to the steam drum body 1, and the vaporization cooling system also includes a forced circulation system and a natural circulation system; wherein, the The forced circulation system includes a forced circulation pump 14 and a first heat exchanger 12 connected in sequence through pipelines, and the input and output ends of the forced circulation system are connected with the steam drum body 1 to form a forced circulation loop. The water in the drum body 1 enters the steam drum body 1 from a high position after passing through the forced circulation system; the natural circulation system includes a second heat exchanger 13, and the second heat exchanger 13 is connected with the steam drum The main bodies 1 are connected by pipelines to form a natural circulation loop.

Specifically, the steam-water mixture is separated from the steam-water in the steam drum body 1, and the steam is output by the steam outlet pipeline 9, which can be sent to the steam pipe network in the factory area, and can also be used to replenish the water added into the steam drum body 1. Heating to ensure normal operation when heat enters the first heat exchanger 12 and the second heat exchanger 13 .

In some embodiments, in order to improve the working efficiency of the forced circulation system and the natural circulation system, the forced circulation system and the natural circulation system respectively include at least one first heat exchanger 12 and at least one second heat exchanger 13; Specifically, one of the first heat exchangers 12 is connected in series in the forced circulation system, and the other first heat exchangers 12 are connected in parallel to the system. The circulation loops connected by each first heat exchanger 12 can work independently or Cooperative work; Similarly, the natural circulation system also has a second heat exchanger 13 in series, and at least one second heat exchanger 13 can also be connected in parallel, and the circulation loops connected by each second heat exchanger 13 can work independently, or They can work together; in order to avoid system suspension when the first heat exchanger 12 and the second heat exchanger 13 fail, a backup heat exchanger is also connected in parallel.

As one of the embodiments, the forced circulation system also includes a forced circulation outlet pipeline 6, a forced circulation intermediate pipeline 7, and a forced circulation inlet pipeline 8. Water is driven from the steam drum body 1 and flows through the The forced circulation outlet pipeline 6, the forced circulation pump 14, the forced circulation intermediate pipeline 7, the first heat exchanger 12, the forced circulation inlet pipeline 8, and return to the steam drum body 1 to form a forced circulation loop; The forced circulation inlet pipeline 8 is arranged on the upper side of the steam drum body 1 , and the forced circulation outlet pipeline 6 is connected with the lower side of the steam drum body 1 .

Specifically, the interface of the forced circulation outlet pipeline 6 on the drum body 1 is located at the lower side of the steam drum body 1, and the interface of the forced circulation inlet pipeline 8 on the steam drum body 1 Located on the upper side of the steam drum body 1, water can enter the interior of the steam drum body 1 from a high position after passing through the first heat exchanger 12, thereby enhancing the steam-water separation effect.

As one of the implementations, the forced circulation outlet pipeline 6 and the forced circulation inlet pipeline 8 are respectively provided with a high-pressure circulation outlet valve 16 and a high-pressure circulation inlet valve 17 for testing and system operation. Regulates internal flow.

Further, the high-pressure circulation outlet valve 16 and the high-pressure circulation inlet valve 17 can adopt pneumatic/electric control valves, pneumatic/electric gate valves, pneumatic/electric ball valves, etc., which can automatically adjust the pipeline of the forced circulation system.

In some embodiments, in order to ensure the safe and stable operation of the system, flow sensors and temperature sensors can also be installed on each pipeline of the forced circulation system to detect the flow and temperature in each pipeline, so as to facilitate timely adjustment The flow and temperature ensure the stability of the system operation.

As one of the implementations, the forced circulation inlet pipeline 8 and the steam outlet pipeline 9 are respectively arranged on both sides of the steam drum body 1 .

As one of the embodiments, the natural circulation system also includes a natural circulation outlet pipeline 2 and a natural circulation inlet pipeline 3, water flows from the steam drum body 1 through the natural circulation outlet pipeline 2, the second Heat exchanger 13, natural circulation inlet pipeline 3, and return to described steam drum body 1, form natural circulation circuit; Described natural circulation outlet pipeline 2 and described natural circulation inlet pipeline 3 and described steam drum body 1's underside connection.

Further, in order to adjust the internal flow during the test process and system operation, the natural circulation outlet pipeline 2 and the natural circulation inlet pipeline 3 are respectively provided with a natural circulation outlet valve 18 and a natural circulation inlet valve 19; Pneumatic/electric control valves, pneumatic/electric gate valves, pneumatic/electric ball valves, etc. can be used to automatically adjust the pipeline of the natural circulation system.

Similarly, for the safe and stable operation of the system, flow sensors and temperature sensors can also be installed on each pipeline of the natural circulation system to detect the flow and temperature in each pipeline, so as to adjust the flow and temperature in time , to ensure the stability of the system operation.

As one of the embodiments, the drum body 1 is further provided with a middle partition 20, and a high water level gauge 10 and a low water level gauge 11 for detecting the liquid level.

Specifically, the natural circulation outlet pipeline 2 in the natural circulation system is connected to the high water level side of the steam drum body 1 , and the natural circulation inlet pipeline 3 is connected to the low water level side of the steam drum body 1 .

As one of the embodiments, the water replenishment system includes a replenishment water pump 15, and a replenishment water inlet pipeline 4 connected with the steam drum body 1, and the replenishment water pump 15 is also connected with a replenishment water source pipeline 5, replenishing the water inlet into the steam drum body The water in 1 will be deoxidized first, and according to actual needs, the water added into the steam drum body 1 can also be heated, and a part of the steam output in the steam drum body 1 can be used to heat the supplementary water; Better control the water level in the steam drum body 1, avoid the water in the steam drum body 1 from exceeding the maximum water level threshold, and the steam drum body 1 is also provided with a drain.

S1: supply water to the steam drum body 1 by the water supply system to ensure that the liquid level in the steam drum body 1 is normal;

Specifically, the set water level in the drum body is H0-H1, wherein H0 is the minimum water level threshold, and H1 is the highest water level threshold, measured by the high water level gauge 10 and the low water level gauge 11 in the steam drum body It is the current water level value. When the water level in the steam drum body is higher than the maximum water level threshold, the water replenishment will be stopped. When the water level in the steam drum body is lower than the minimum water level threshold, the pneumatic water replenishment system will start to replenish water to keep the water level at the lowest level. Between the water level threshold and the maximum water level threshold; supplementary water is preferably deaerated water and properly heated.

S2: Open the forced circulation system, and the water in the steam drum body 1 enters the first heat exchanger 12 by the forced circulation pump 14 for heat exchange, and the steam-water mixture formed after heat exchange flows back into the steam drum body 1, and Steam-water separation, wherein the water of the forced circulation system enters the steam drum body 1 from the upper side of the steam drum body 1;

Specifically, in the preparation stage of the forced circulation system, the inside of the forced circulation system must be exhausted first, and the forced circulation system belongs to high-level return water, which can ensure that the water filling of each pipeline is fuller.

S3: Open the natural circulation system, the water in the steam drum body 1 enters the second heat exchanger 13 for heat exchange, and the steam-water mixture formed is returned to the steam drum body 1, and the steam-water separation is performed.

Specifically, when the natural circulation system is working, the valves on each pipeline in the natural circulation system will be opened correspondingly, the valve on the high water level side will be opened first, and then the valve on the low water level side will be opened, that is, the natural circulation outlet valve 18 and the natural circulation outlet valve will be opened successively. Natural circulation inlet valve 19.

In the steam-water cooling system of the present application, when the heat exchangers in the forced circulation system and the natural circulation system start to work and during the working process, the supplementary water of the supplementary water pump can be adjusted according to the real-time monitoring of the high water level gauge and the low water level gauge Condition.

In some embodiments, temperature sensors can be installed on the steam drum body and each pipeline to reflect the working conditions of each heat exchanger according to the temperature, so as to adjust the forced circulation pump and ensure the stable operation of the first heat exchanger.

In some embodiments, when the work of the forced circulation pump changes, the replenishment water and the inlet and outlet valves of the forced circulation system and the natural circulation system can be dynamically adjusted to ensure the stability of the flow state.

To sum up, the present invention provides a vaporization cooling system and its method with a control high-loop enhanced steam-water separation, which can greatly reduce the amount of water released during the test and commissioning process, thereby shortening the overall cycle of the test and commissioning process and saving water. At the same time, it strengthens the steam-water separation effect, utilizes the heat transfer heat of the steam-water cooling system to a greater extent, and improves the working efficiency of the vaporization cooling system, which has very positive significance for the practical application of the metallurgical industry.

Those skilled in the art will appreciate that the present invention may be embodied in many other specific forms without departing from the spirit and scope of the invention. Although an embodiment of the invention has been described, it should be understood that the invention should not be limited to this embodiment, and that changes and modifications may be made by those skilled in the art within the spirit and scope of the invention as defined by the appended claims.

Claims

An evaporative cooling system with a controlled high-loop enhanced steam-water separation, including a steam drum body, a water replenishment system, and a steam outlet pipeline, the water replenishment system is connected to the steam drum body, and is used to replenish water to the steam drum body. The steam outlet pipeline is connected to the steam drum body, and it is characterized in that the vaporization cooling system also includes a forced circulation system and a natural circulation system; wherein,

The forced circulation system includes a forced circulation pump and a first heat exchanger connected in sequence through pipelines. The input and output ends of the forced circulation system are connected to the steam drum body to form a forced circulation loop. The steam drum body The water inside enters the steam drum body from a high position after passing through the forced circulation system;

The natural circulation system includes a second heat exchanger, and the second heat exchanger is connected to the steam drum body through pipelines to form a natural circulation loop.
According to claim 1, the steam-water cooling system with controlled high-loop enhanced steam-water separation is characterized in that, the forced circulation system also includes a forced circulation outlet pipeline, a forced circulation intermediate pipeline, and a forced circulation inlet pipeline, and the water flows from The steam drum body drives and flows through the forced circulation outlet pipeline, the forced circulation pump, the forced circulation intermediate pipeline, the first heat exchanger, the forced circulation inlet pipeline in sequence, and returns to the steam drum body; The forced circulation inlet pipeline is arranged on the upper side of the steam drum body, and the forced circulation outlet pipeline is connected to the lower side of the steam drum body.
According to claim 2, the steam-water cooling system with control high-loop enhanced steam-water separation is characterized in that, the forced circulation outlet pipeline and the forced circulation inlet pipeline are respectively provided with a high-pressure circulation outlet valve and a high-pressure circulation inlet valve .
The steam-water cooling system with controlled high-loop enhanced steam-water separation according to claim 2, wherein the forced circulation inlet pipeline and the steam outlet pipeline are respectively arranged on both sides of the steam drum body.
According to claim 1, the steam-water cooling system with controlled high-loop enhanced steam-water separation is characterized in that, the natural circulation system also includes a natural circulation outlet pipeline and a natural circulation inlet pipeline, and water flows from the steam drum body Flow through the natural circulation outlet pipeline, the second heat exchanger, the natural circulation inlet pipeline in turn, and return to the drum body; the natural circulation outlet pipeline and the natural circulation inlet pipeline are connected with the The lower side of the drum body is connected.
According to claim 5, the steam-water cooling system with controlled high-loop enhanced steam-water separation is characterized in that, the natural circulation outlet pipeline and the natural circulation inlet pipeline are respectively provided with a natural circulation outlet valve and a natural circulation inlet valve .
The steam-water cooling system with a controlled high-loop enhanced steam-water separation according to claim 1, wherein an intermediate partition is also arranged in the steam drum body.
According to claim 1, the steam-water cooling system with a control high circuit and enhanced steam-water separation is characterized in that a high water level gauge and a low water level gauge for detecting the liquid level are also arranged in the steam drum body.
The steam-water cooling system with a control high circuit and enhanced steam-water separation according to claim 1, wherein the water supply system includes a water supply pump and a water supply pipeline connected to the steam drum body.
A steam-water cooling method with controlled high-loop enhanced steam-water separation, characterized in that it comprises the following steps:

S1: replenish water to the steam drum body by the water supply system to ensure that the liquid level in the steam drum body is normal;

S2: Open the forced circulation system, the water in the steam drum body enters the first heat exchanger by the forced circulation pump to exchange heat, and the steam-water mixture formed after returning to the steam drum body, and steam-water separation is carried out, wherein , the water of the forced circulation system enters the steam drum body from the upper side of the steam drum body;

S3: Open the natural circulation system, the steam-water mixture formed after the water in the steam drum body enters the second heat exchanger for heat exchange flows back into the steam drum body, and separates the steam-water.