A system and method for realizing high-efficiency deoxygenation of large-flow water replenishment for industrial heating units

Abstract

The present invention discloses a system and method for realizing high-efficiency deoxygenation of large-flow water replenishment of industrial heating units, including a boiler, a high-pressure cylinder, a medium-pressure cylinder, a low-pressure cylinder and an external deaerator, wherein the boiler exhaust is connected to the inlet of the high-pressure cylinder; the inlet of the external deaerator is connected to the make-up water booster pump, and the inlet of the make-up water booster pump is connected to the desalted water tank; the outlet of the external deaerator is connected to the booster pump, and the outlet of the booster pump is divided into two paths, one of which is connected to the outlet of the second low-pressure heater through the first valve group, and the other is connected to the outlet of the third low-pressure heater through the second valve group. The external deaerator of the present invention adopts an integrated structure, which is suitable for the water replenishment and deoxygenation requirements after large-flow industrial steam supply of coal-fired power generation units; it can meet the requirements of the main engine to maintain high deoxygenation efficiency in a wide load variation range; the condensate temperature rises greatly, and it can be flexibly connected to the inlet of a certain level of low-pressure heater to achieve step-by-step efficient utilization of energy.

Description

[Technical field]

[0001] The invention relates to a system and method for realizing high-efficiency deoxygenation of large-flow water replenishment of an industrial heating unit. [Background technology]

[0002] With the continuous and in-depth advancement of air pollution prevention and control, high-pollution, high-energy-consuming decentralized coal-fired and oil-fired boiler rooms are gradually shut down, and steam-using enterprises are encouraged to settle in newly built industrial parks near coal-fired units. The centralized steam supply from high-efficiency and large-capacity coal-fired power generation units to steam-using industrial parks will help control the total amount of regional coal and fuel consumption. Affected by factors such as steam supply distance, production process, and investment, the condensate corresponding to industrial steam supply is not recycled. In order to maintain the steam-water balance of coal-fired power generation and heating units, an equal amount of desalted water needs to be added to the thermal system. In order to ensure the safe operation of the thermal system, synchronous thermal deoxidation is required. The current water replenishment deoxygenation technology is mainly condenser atomization deoxygenation technology, the core of which is to add a spray system with good atomization effect inside the exhaust device, and spray the replenishment water with a certain oxygen content into the condenser from the throat of the condenser in a fine mist through the nozzle, and use the turbine exhaust steam to fully heat the droplets. When the droplets are heated to a temperature equal to or very close to the saturation temperature corresponding to their pressure, all the oxygen in them will be precipitated from the replenishment water droplets, and the oxygen will be directly discharged from the condenser through the air extraction pipe set in the air cooling area, and the deoxygenated replenishment water droplets will flow to the bottom of the hot well of the condenser. Atomization deoxygenation technology is a contact technology, and a good and lasting atomization effect is the technical key to ensure the deoxygenation effect. Limited by factors such as the number of nozzles and flow field disturbances, atomization deoxygenation technology cannot guarantee a good deoxygenation effect under large-flow water replenishment conditions. [Summary of the invention]

[0003] The purpose of the present invention is to solve the problem that the atomization deoxygenation technology in the prior art cannot guarantee a good deoxygenation effect under large-flow water replenishment conditions, and to provide a system and method for realizing high-efficiency deoxygenation of large-flow water replenishment for industrial heating units, which can achieve a good deoxygenation effect of large-flow low-temperature desalinated make-up water for the unit.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions:

[0005] A system for realizing high-efficiency deoxygenation of large-flow water replenishment for industrial heating units, comprising:

[0006] Boiler, the boiler exhaust is connected to the high pressure cylinder inlet;

[0007] High-pressure cylinder, the exhaust steam of the high-pressure cylinder returns to the boiler for secondary heating, and the heated steam enters the medium-pressure cylinder;

[0008] The exhaust steam of the intermediate pressure cylinder is divided into two paths, one path enters the low pressure cylinder, and the other path is connected to the external deaerator;

[0009] The exhaust end of the low-pressure cylinder is connected to the condenser, the condensate pump, the first low-pressure heater, the second low-pressure heater, the third low-pressure heater and the fourth low-pressure heater in sequence; the high-pressure cylinder, the medium-pressure cylinder, the low-pressure cylinder and the rotating shaft of the generator are coaxially connected;

[0010] An external deaerator, the inlet of the external deaerator is connected to the make-up water booster pump, and the inlet of the make-up water booster pump is connected to the desalted water tank; the outlet of the external deaerator is connected to the booster pump, and the outlet of the booster pump is divided into two paths, one path is connected to the outlet of the second low-pressure heater through the first valve group, and the other path is connected to the outlet of the third low-pressure heater through the second valve group.

[0011] The present invention is further improved in that:

[0012] Both the water replenishment booster pump and the booster pump use two booster pumps in parallel to increase pressure, one in operation and the other on standby.

[0013] The external deaerator adopts an integrated structure and is a deaerator that also has a water storage function.

[0014] The exhaust steam from the medium-pressure cylinder enters the low-pressure cylinder through the first regulating valve.

[0015] The inlet of the external deaerator is connected to the make-up water booster pump through a second regulating valve.

[0016] A method for realizing high-efficiency deoxygenation of large-flow water replenishment of an industrial heating unit, comprising the following steps:

[0017] When the steam turbine generator set is supplied with a large amount of industrial steam, an equal amount of low-temperature desalted water at the outlet of the desalted water tank is synchronously supplemented to the unit's thermal system. After being pressurized by the supplementary water booster pump, it enters the external deaerator for thermal heating and deoxygenation. The outlet water is pressurized by the booster pump and returned to the main engine thermal system. According to the difference in the inlet temperature of the third low-pressure heater, the inlet temperature of the fourth low-pressure heater, and the outlet water temperature of the external deaerator, the first valve group and the second valve group are adjusted. The specific adjustment method is as follows:

[0018] When the generator load is high and the outlet water temperature of the external deaerator is higher than the preset value, the second valve group is opened, the first valve group is closed, and the outlet water of the external deaerator enters the fourth low-pressure heater;

[0019] When the generator load is low and the outlet water temperature of the external deaerator is lower than the preset value, the second valve group is closed, the first valve group is opened, and the outlet water of the external deaerator enters the third low-pressure heater;

[0020] When the generator is at an intermediate load, the first valve group and the second valve group are opened at the same time, and the outlet water of the external deaerator enters the third low-pressure heater and the fourth low-pressure heater at the same time.

[0021] A further improvement of the above method is that the heating steam for the external deaerator is taken from the extraction steam of the medium- and low-pressure connecting pipes of the steam turbine, and when the load is low, the medium- and low-pressure connecting pipes are used to supply heat by closing the opening of the heat regulating valve to produce throttling to ensure the extraction steam flow and pressure; the desalinated make-up water and the heating steam are contacted and exchanged heat inside the external deaerator, and the desalinated make-up water is throttled by closing the opening of the regulating valve before entering the desalinated make-up water, so that the pressure of the desalinated make-up water is equal to the pressure of the heating steam.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The external deaerator of the present invention is the core of the system of the present invention. It adopts an integrated structure. The deaerator and the water tank are specially designed to make it a new type of deaerator that can both deoxygenate and store water. The present invention realizes a system for large-scale coal-fired industrial heating units with high-efficiency deoxygenation with large flow water replenishment. It is suitable for coal-fired generating units (300MW and above) with large flow (400-600t / h) industrial steam supply and water replenishment and deoxygenation requirements; it can meet the requirements of the main engine to maintain high deoxygenation efficiency in a wide load variation range; the condensate temperature rise is large, and it can be flexibly connected to the inlet of a certain level of low-pressure heater to achieve high-efficiency step-by-step utilization of energy.

Brief Description of the Drawings

[0024] Figure 1 It is a schematic diagram of the system structure of the present invention.

[0025] Among them: 1- boiler; 2- high-pressure cylinder; 3- medium-pressure cylinder; 4- low-pressure cylinder; 5- generator; 6- medium- and low-pressure connecting pipe heating regulating valve 7- condenser 8- condensate pump; 9- first low-pressure heater; 10- second low-pressure deaerator; 11- third low-pressure deaerator; 12- fourth low-pressure deaerator; 13- demineralized water tank; 14- make-up water booster pump; 15- regulating valve; 16- external deaerator; 17- booster pump; 18~19- valve group. [Specific implementation method]

[0026] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiment of the present invention. Obviously, the described embodiment is only an embodiment of a part of the present invention, not all embodiments, and is not intended to limit the scope of the present invention. In addition, in the following description, the description of well-known structures and technologies is omitted to avoid unnecessary confusion of the concepts disclosed in the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work should fall within the scope of protection of the present invention.

[0027] Various structural schematic diagrams of the embodiments disclosed in the present invention are shown in the accompanying drawings. These figures are not drawn to scale, and some details are magnified and some details may be omitted for the purpose of clear expression. The shapes of various regions and layers shown in the figures and the relative sizes and positional relationships therebetween are only exemplary, and may deviate in practice due to manufacturing tolerances or technical limitations, and those skilled in the art may additionally design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0028] In the context of the present disclosure, when a layer / element is referred to as being "on" another layer / element, the layer / element may be directly on the other layer / element, or an intervening layer / element may exist between them. In addition, if a layer / element is "on" another layer / element in one orientation, the layer / element may be "under" the other layer / element when the orientation is reversed.

[0029] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0030] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0031] See also Figure 1 The present invention realizes a system for high-flow water replenishment and high-efficiency deoxidation of an industrial heating unit, comprising a boiler 1, wherein the exhaust steam of the boiler 1 is connected to the inlet of a high-pressure cylinder 2, and the exhaust steam of the high-pressure cylinder 2 is returned to the boiler 1 to preheat the boiler feed water, and the preheated exhaust steam enters the medium-pressure cylinder 3; the exhaust steam of the medium-pressure cylinder 3 is divided into two paths, one path enters the low-pressure cylinder 4 through the first regulating valve 6, and the other path is connected to the external deaerator 16; the rotating shafts of the high-pressure cylinder 1, the medium-pressure cylinder 3, the low-pressure cylinder 4 and the generator 5 are coaxially connected; the exhaust end of the low-pressure cylinder 4 is connected to the condenser 7, the condensate pump 8, the first low-pressure heater 9, the second low-pressure heater 10, the third low-pressure heater 11 and the fourth low-pressure heater 12 in sequence;

[0032] The inlet of the external deaerator 16 is connected to the make-up water booster pump 14 through the second regulating valve 15, and the inlet of the make-up water booster pump 14 is connected to the desalted water tank 13; the outlet of the external deaerator 16 is connected to the booster pump 17, and the outlet of the booster pump 17 is divided into two paths, one is connected to the outlet of the second low-pressure heater 10, and the other is connected to the outlet of the third low-pressure heater 11.

[0033] The water replenishment booster pump 14 and the booster pump 17 of the present invention both use two groups of booster pumps connected in parallel to increase pressure.

[0034] The external deaerator 16 of the present invention adopts an integrated structure, and the deaerator and the water tank are specially designed to make it a new type of deaerator that can both deoxygenate and store water. When the steam turbine generator set supplies a large amount of industrial steam, an equal amount of low-temperature desalted water at the outlet of the desalted water tank 13 needs to be simultaneously supplemented to the unit's thermal system, and after being pressurized by the supplementary water booster pump, it enters the external deaerator 16 for thermal heating and deoxygenation. The outlet water is pressurized by the booster pump 17 and returned to the main engine thermal system. According to the difference in the inlet temperature of the third low-pressure heater 11 of the main engine, the inlet temperature of the fourth low-pressure heater 12, and the outlet water temperature of the external deaerator 16, a reasonable selection is made through the switch conditions of the first valve group 18 and the second valve group 19 to achieve efficient utilization of energy cascades.

[0035] The specific method for selecting the switch conditions of the first valve group 18 and the second valve group 19 is as follows:

[0036] When the load of the generator 5 is high and the outlet water temperature of the external deaerator 16 is higher than the preset value, the second valve group 19 is opened, the first valve group 18 is closed, and the outlet water of the external deaerator 16 enters the fourth low-pressure heater 12;

[0037] When the load of the generator 5 is low and the outlet water temperature of the external deaerator 16 is lower than the preset value, the second valve group 19 is closed, the first valve group 18 is opened, and the outlet water of the external deaerator 16 enters the third low-pressure heater 11;

[0038] When the generator 5 is at an intermediate load, the first valve group 18 and the second valve group 19 are opened simultaneously, and the water discharged from the external deaerator 16 enters the third low-pressure heater 11 and the fourth low-pressure heater 12 simultaneously.

[0039] The heating steam for the external deaerator 16 is extracted from the medium- and low-pressure connecting pipes of the steam turbine. When the load is low, the medium- and low-pressure connecting pipes are used to supply heat to the heating regulating valves, which are closed to produce throttling to ensure the extraction flow and pressure. The desalinated make-up water and the heating steam are in contact and heat exchange with each other inside the external deaerator 16. Before the desalinated make-up water enters the desalinated make-up water, the regulating valve 15 is closed to produce throttling to make the pressure of the desalinated make-up water equal to the pressure of the heating steam.

[0040] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A method for realizing high-efficiency deoxygenation of large-flow water replenishment for an industrial heating unit, the method being based on a system for realizing high-efficiency deoxygenation of large-flow water replenishment for an industrial heating unit, the system comprising a boiler (1), a high-pressure cylinder (2), a medium-pressure cylinder (3), a low-pressure cylinder (4), and an external deaerator (16); The exhaust steam of the boiler (1) is connected to the inlet of the high-pressure cylinder (2); the exhaust steam of the high-pressure cylinder (2) returns to the boiler (1) to achieve secondary heating, and the heated steam enters the medium-pressure cylinder (3); the exhaust steam of the medium-pressure cylinder (3) is divided into two paths, one path enters the low-pressure cylinder (4), and the other path is connected to the external deaerator (16); the exhaust end of the low-pressure cylinder (4) is connected to the condenser (7), the condensate pump (8), the first low-pressure heater (9), the second low-pressure heater (10), the third low-pressure heater (11) and the fourth low-pressure heater (12) in sequence; the high-pressure cylinder (2), the medium-pressure cylinder (3), the low-pressure cylinder (4) and the rotating shaft of the generator (5) are coaxially connected; the inlet of the external deaerator (16) is connected to the supplementary water booster pump (14), and the inlet of the supplementary water booster pump (14) is connected to the desalted water tank (13); the outlet of the external deaerator (16) is connected to the booster pump (17), and the outlet of the booster pump (17) is divided into two paths, one of which is connected to the outlet of the second low-pressure heater (10) through the first valve group (18), and the other is connected to the outlet of the third low-pressure heater (11) through the second valve group (19); characterized in that The method comprises the following steps: When a large amount of industrial steam is supplied to the steam turbine generator set, an equal amount of low-temperature desalted water at the outlet of the desalted water tank (13) is synchronously supplemented to the unit thermal system, and after being pressurized by the supplementary water booster pump (14), it enters the external deaerator (16) for thermal heating and deoxygenation. The outlet water is pressurized by the booster pump (17) and returned to the main engine thermal system. According to the difference between the inlet temperature of the third low-pressure heater (11), the inlet temperature of the fourth low-pressure heater (12), and the outlet water temperature of the external deaerator (16), the first valve group (18) and the second valve group (19) are adjusted. The specific adjustment method is as follows: When the load of the generator (5) is high and the outlet water temperature of the external deaerator (16) is higher than a preset value, the second valve group (19) is opened, the first valve group (18) is closed, and the outlet water of the external deaerator (16) enters the fourth low-pressure heater (12); When the load of the generator (5) is low and the outlet water temperature of the external deaerator (16) is lower than a preset value, the second valve group (19) is closed, the first valve group (18) is opened, and the outlet water of the external deaerator (16) enters the third low-pressure heater (11); When the generator (5) is at an intermediate load, the first valve group (18) and the second valve group (19) are opened simultaneously, and the water outlet from the external deaerator (16) enters the third low-pressure heater (11) and the fourth low-pressure heater (12) simultaneously.

2. The method for realizing high-efficiency deoxygenation of large-flow water replenishment of industrial heating units according to claim 1 is characterized in that: The make-up water booster pump (14) and the booster pump (17) are both pressurized by connecting two booster pumps in parallel, one in operation and the other in standby.

3. The method for realizing high-efficiency deoxygenation of large-flow water replenishment of industrial heating units according to claim 1 is characterized in that: The external deaerator (16) adopts an integrated structure and is a deaerator that also has a water storage function.

4. The method for realizing high-efficiency deoxygenation of large-flow water replenishment of industrial heating units according to claim 1 is characterized in that: One exhaust steam path of the medium-pressure cylinder (3) enters the low-pressure cylinder (4) through the first regulating valve (6).

5. The method for realizing high-efficiency deoxygenation of large-flow water replenishment of industrial heating units according to claim 1 is characterized in that: The inlet of the external deaerator (16) is connected to the make-up water booster pump (14) via a second regulating valve (15).

6. The method for realizing high-efficiency deoxygenation of large-flow water replenishment of industrial heating units according to claim 1 is characterized in that: The heating steam for the external deaerator (16) is extracted from the medium- and low-pressure connecting pipes of the steam turbine. When the load is low, the medium- and low-pressure connecting pipes are used to supply heat to the heating steam. The regulating valves are closed to reduce the opening to generate throttling to ensure the flow rate and pressure of the extracted steam. The desalinated make-up water and the heating steam are contacted and exchanged with each other inside the external deaerator (16). Before the desalinated make-up water enters the external deaerator (16), the regulating valve (15) is closed to reduce the opening to generate throttling to make the pressure of the desalinated make-up water equal to the pressure of the heating steam.

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