CN216744308U - Energy-saving device suitable for boiler blow-down system - Google Patents
Energy-saving device suitable for boiler blow-down system Download PDFInfo
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- CN216744308U CN216744308U CN202220285505.7U CN202220285505U CN216744308U CN 216744308 U CN216744308 U CN 216744308U CN 202220285505 U CN202220285505 U CN 202220285505U CN 216744308 U CN216744308 U CN 216744308U
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Abstract
The utility model relates to an energy-saving device suitable for a boiler blow-down system, which comprises a steam drum, a primary continuous blow-down flash tank, a secondary blow-down flash tank, a steam ejector and a deaerator, wherein the steam drum is provided with a continuous blow-down outlet and a periodic blow-down outlet, the primary continuous blow-down flash tank is provided with a continuous blow-down inlet, a primary steam outlet and a first sewage outlet, and the secondary blow-down flash tank is provided with a blow-down water inlet, a periodic blow-down inlet, a secondary steam outlet and a second blow-down water outlet. The steam ejector is provided with a working steam inlet, an injected steam inlet and a mixed steam outlet, and the deaerator is provided with a deaerator steam inlet. The utility model is particularly suitable for some enterprises which can not further recover the heat of the sewage through the desalted water, can effectively improve the heat recovery rate and the working medium recovery rate of the boiler sewage, and realizes the utilization of quality improvement.
Description
Technical Field
The utility model relates to various industrial fields, in particular to an energy-saving device suitable for a boiler blow-down system.
Background
Steam in the energy era plays a vital role in industrial and social development, and is used as blood to continuously convey heat energy and power for the production process in various industrial fields, thereby promoting continuous innovation of the energy field technology. The boiler uses water as a working medium and becomes important steam generating equipment by converting chemical energy into heat energy, steam is continuously evaporated to cause that dissolved salts, colloid, water slag and the like brought into a system by feed water are continuously accumulated and concentrated to influence the steam quality, the equipment is corroded and even potential safety hazards are brought, continuous pollution discharge and periodic pollution discharge need to be set for controlling boiler water quality, and the pollution discharge is an important measure for ensuring the safe and stable operation of the boiler.
The blowdown water is saturated water under the steam pocket pressure, and temperature and pressure are all higher, and the blowdown rate is about 2 ~ 5%, and the continuous discharge has caused certain heat loss and the waste of water resource, reduces system net efficiency, still needs to consume partial circulating water or production water simultaneously and cools off. At present, the better method for recovering energy of most enterprises is to recover secondary steam by arranging a continuous drainage flash tank, the secondary steam directly enters a deaerator, and the residual continuous drainage water is used for heating demineralized water through a heat exchanger; the periodic sewage is not beneficial to recovery due to overlarge instantaneous quantity, the secondary steam is directly exhausted to the atmosphere, and the residual continuous drainage and the fixed drainage are discharged to a sewage-discharging cooling pool or a cooler according to the requirement of the discharged temperature, are cooled by production water or circulating water and are sent out by a sewage-discharging pump for treatment. Because the salt content of the sewage is higher, the demineralized water heat exchanger is easy to scale, and the heat exchange effect is reduced after long-term operation.
For some enterprises, especially in the coal chemical industry, petrochemical engineering project, demineralized water has exchanged heat to higher temperature level with condensate water or technology material before advancing the oxygen-eliminating device, the dilatation steam of arranging in succession usually directly connects to the oxygen-eliminating device and uses, cause the oxygen-eliminating device operating pressure to correspond the unable recovery of heat of temperature level below the saturation temperature, recovery pressure is low excessively, and difficult suitable heat trap that matches, the economic nature is relatively poor, so the atmosphere is directly diffused to the heat, some enterprises middling pressure deoxidization system continuous emission heat recovery is about 31 ~ 66%, high pressure deoxidization system continuous emission heat recovery is about 59 ~ 71%, the high recovery rate that produces vapour pressure is high more high. The regular exhaust is not suitable for recycling due to interruption and overlarge instantaneous quantity, the heat is also directly diffused into the atmosphere, the waste of partial heat and working media is caused, and meanwhile, the steam exhausted into the atmosphere also worsens the operation environment of enterprises, and the local heat pollution and the heat island effect are caused.
Therefore, the inventor provides an energy-saving device suitable for a boiler blow-off system by virtue of experience and practice of related industries for many years, so as to overcome the defects in the prior art.
SUMMERY OF THE UTILITY MODEL
The utility model aims to provide an energy-saving device suitable for a boiler sewage system, which is particularly suitable for part of enterprises which can not further recover heat of sewage through desalted water, can effectively improve the heat recovery rate and working medium recovery rate of boiler sewage, and realizes quality improvement and utilization.
The object of the utility model is achieved by an energy-saving device suitable for a boiler blow-down system, comprising:
a steam drum having a continuous blowdown outlet and a periodic blowdown outlet;
the primary continuous sewage discharge flash tank is provided with a continuous sewage discharge inlet, a primary steam outlet and a first sewage discharge outlet, and the continuous sewage discharge outlet and the continuous sewage discharge inlet can be connected in a switching mode;
the secondary pollution discharge flash vessel is provided with a pollution discharge water inlet, a periodic pollution discharge inlet, a secondary steam outlet and a second pollution discharge water outlet, the periodic pollution discharge outlet and the periodic pollution discharge inlet can be connected in an on-off manner, and the first pollution discharge outlet and the pollution discharge water inlet can be connected in an on-off manner;
the steam ejector is provided with a working steam inlet, an injected steam inlet and a mixed steam outlet, the primary steam outlet is connected with an external steam pipe network in a switching way, the primary steam outlet and the external steam pipe network are both connected with the working steam inlet in a switching way, and the secondary steam outlet is connected with the injected steam inlet in a switching way;
the deaerator is provided with a deaerator steam inlet, and the mixed steam outlet is connected with the deaerator steam inlet; the steam inlet of the deaerator can be connected with an external steam pipe network in a connection and disconnection manner.
In a preferred embodiment of the present invention, the deaerator is a medium pressure deaerator, and the working pressure of the deaerator is 0.2 to 0.5mpa.g, the pressure in the steam drum is greater than or equal to 0.8mpa.g, the pressure of the primary steam output from the primary steam outlet is greater than or equal to 0.5mpa.g, and the pressure of the external steam output from the external steam pipe network is greater than or equal to 0.5 mpa.g.
In a preferred embodiment of the present invention, the deaerator is a high pressure deaerator, and the operating pressure of the deaerator is 0.518mpa.g, the pressure in the steam drum is greater than or equal to 5.9mpa.g, the pressure of the primary steam output from the primary steam outlet is greater than or equal to 1.0mpa.g, and the pressure of the external steam output from the external steam pipe network is greater than or equal to 1.0 mp.g.
In a preferred embodiment of the present invention, the total extracted steam amount per unit time at the injected steam inlet is 1.2 to 1.5 times the sum of the primary steam amount per unit time at the primary steam outlet and the secondary steam amount per unit time at the secondary steam outlet.
In a preferred embodiment of the present invention, the external steam output by the external steam pipe network is superheated steam, and the superheated temperature of the superheated steam is greater than or equal to 5 ℃.
In a preferred embodiment of the present invention, the steam ejector includes at least two stages of ejectors connected in series in sequence, each stage of ejector having a high pressure steam port, a low pressure steam port and a mixed steam port, the mixed steam port of the ejector of the previous stage being connected to the low pressure steam port of the ejector of the next stage; the high-pressure steam ports form a working steam inlet, the low-pressure steam port of the first-stage ejector forms an injected steam inlet, and the mixed steam port of the last-stage ejector forms a mixed steam outlet.
In a preferred embodiment of the utility model, the single-stage injection coefficient of each stage of injector is greater than or equal to 0.2, and the total amount of steam in unit time of the plurality of high-pressure steam ports is not more than 60% of the gas consumption of the deaerator.
In a preferred embodiment of the utility model, the working pressure of the secondary pollution discharge flash tank is normal pressure or vacuum pressure, and the operating temperature is greater than or equal to 85 ℃; and when the working pressure of the secondary pollution discharge flash tank is normal pressure, the height of the bottom surface of the secondary pollution discharge flash tank from the ground is at least 5 m.
In a preferred embodiment of the present invention, the secondary steam outlet can be connected to the deaerator steam inlet in a switching manner.
In a preferred embodiment of the present invention, the continuous blowdown outlet is connected with the continuous blowdown inlet through a continuous blowdown pipe, and a continuous blowdown gate valve is arranged on the continuous blowdown pipe; the periodic blowdown outlet is connected with the periodic blowdown inlet through a periodic blowdown pipe, and a periodic blowdown switch valve is arranged on the periodic blowdown pipe; the first sewage draining outlet is connected with the sewage draining inlet through a first sewage draining pipe, a first control valve is arranged on the first sewage draining pipe, and the opening degree of the first control valve is controlled by the liquid level in the primary continuous sewage draining flash tank; a second sewage discharge pipe is connected at the second sewage discharge outlet, a second control valve is arranged on the second sewage discharge pipe, and the opening degree of the second control valve is controlled by the liquid level in the secondary sewage discharge flash tank; the secondary steam outlet is connected with the injected steam inlet through a secondary steam pipe, and a secondary steam gate valve and a secondary steam check valve are arranged on the secondary steam pipe;
the primary steam outlet is connected with a primary steam pipe, the output end of the external steam pipe network is connected with a first external steam pipe and a second external steam pipe, the end parts of the primary steam pipe and the first external steam pipe are both connected with the first end of the working steam pipe, the second end of the working steam pipe is connected with the working steam inlet, the primary steam pipe is provided with a primary steam gate valve and a primary steam check valve, the working steam pipe is provided with a third control valve, and the opening degree of the third control valve is controlled by the pressure in the secondary steam pipe; a steam outlet pipe is connected to the mixed steam outlet, the end part of the second outer steam pipe is communicated with the end part of the steam outlet pipe and then is connected with the steam inlet of the deaerator through the deaerator steam pipe, a fourth control valve is arranged on the second outer steam pipe, and the opening degree of the fourth control valve is controlled through the pressure in the deaerator; a steam bypass pipe is also connected to the secondary steam pipe, the end of the steam bypass pipe is connected to the steam outlet pipe, and a bypass gate valve is arranged on the steam bypass pipe.
In a preferred embodiment of the present invention, the first control valve, the second control valve, the third control valve and the fourth control valve are all pneumatic valves, the first control valve is an air source failure switch, the second control valve is an air source failure switch, the third control valve is an air source failure switch, and the fourth control valve is an air source failure switch.
In a preferred embodiment of the present invention, the design pressure of the secondary blowdown flash tank is the same as the design pressure of the deaerator when the third control valve fails or the steam ejector fails.
In a preferred embodiment of the utility model, the flow rate of the injected steam inlet is 40-50 m/s, and the flow rate of the working steam inlet is 20-30 m/s; the flow velocity in the secondary steam pipe is 10-20 m/s, and the flow velocity in the steam outlet pipe is 10-20 m/s.
According to the energy-saving device, primary steam produced by the primary continuous blowdown flash tank and secondary steam produced by the deaerator heating steam injection secondary blowdown flash tank are used for heating steam of the deaerator; the heat recovery rate of boiler blow-off water is greatly improved, the working medium recovery rate is improved, the consumption of steam outside the deaerator is reduced, the consumption of production water or circulating water is reduced, the problems of low-grade heat recovery and low-grade heat utilization are solved, and the device has the advantages of energy conservation and consumption reduction, strong operability, safe and reliable system operation, mature and stable equipment, convenience in manufacturing, improvement of enterprise economy and the like.
Drawings
The drawings are only for purposes of illustrating and explaining the present invention and are not to be construed as limiting the scope of the present invention. Wherein:
FIG. 1: the utility model provides a schematic structural diagram of an energy-saving device suitable for a boiler blow-down system.
FIG. 2: the steam ejector provided by the present invention is an enlarged view when a two-stage ejector is used.
The reference numbers illustrate:
1. a steam drum; 11. a continuous blowdown outlet; 111. a continuous sewage drain pipe; 1111. a continuous blowdown gate valve; 12. a periodic blowdown outlet; 121. a periodic sewage draining pipe; 1211. a periodic blowdown switch valve;
2. a primary continuous blowdown flash tank; 21. a continuous blowdown inlet; 22. a primary steam outlet; 221. a primary steam pipe; 2211. a primary steam gate valve; 2212. a primary steam check valve; 222. a working steam pipe; 2221. a third control valve; 23. a first sewage discharge outlet; 231. a first sewage draining pipe; 2311. a first control valve;
3. a secondary pollution discharge flash tank; 31. a sewage draining inlet; 32. a periodic blowdown inlet; 33. a secondary steam outlet; 331. a secondary steam pipe; 3311. a secondary steam gate valve; 3312. a secondary steam check valve; 332. a steam bypass pipe; 3321. a bypass gate valve; 34. a second sewage outlet; 341. a second sewage draining pipe; 3411. a second control valve;
4. a steam ejector; 41. an ejector; 411. a high pressure steam port; 412. a low pressure steam port; 413. a mixed steam port; 4131. a steam outlet pipe;
5. a deaerator; 51. a deaerator steam inlet; 511. a deaerator steam pipe;
6. an external steam pipe network; 61. a first outer steam tube; 62. a second outer steam tube; 621. a fourth control valve.
Detailed Description
In order to more clearly understand the technical features, objects, and effects of the present invention, embodiments of the present invention will now be described with reference to the accompanying drawings.
As shown in fig. 1 and 2, the present embodiment provides an energy saving device suitable for a boiler blow-down system, comprising:
a steam drum 1 having a continuous blowdown outlet 11 and a periodic blowdown outlet 12;
the primary continuous blowdown flash tank 2 is provided with a continuous blowdown inlet 21, a primary steam outlet 22 and a first blowdown water outlet 23, and the continuous blowdown outlet 11 and the continuous blowdown inlet 21 can be connected in a switching mode;
the secondary pollution discharge flash vessel 3 is provided with a pollution discharge water inlet 31, a periodic pollution discharge inlet 32, a secondary steam outlet 33 and a second pollution discharge water outlet 34, the periodic pollution discharge outlet 12 and the periodic pollution discharge inlet 32 can be connected in an on-off manner, and the first sewage discharge outlet 23 and the pollution discharge water inlet 31 can be connected in an on-off manner;
the steam ejector 4 is provided with a working steam inlet, an injected steam inlet and a mixed steam outlet, the primary steam outlet 22 is connected with the external steam pipe network 6 in a switching mode, the primary steam outlet 22 and the external steam pipe network 6 are both connected with the working steam inlet in a switching mode, and the secondary steam outlet 33 is connected with the injected steam inlet in a switching mode;
the deaerator 5 is provided with a deaerator steam inlet 51, and the mixed steam outlet is connected with the deaerator steam inlet 51; the deaerator steam inlet 51 is connected to the external steam pipe network 6 in a switchable manner.
The steam for steam production is in multiple grades aiming at industries such as petrochemical industry and coal chemical industry, the whole plant is a pipe network with several fixed steam grades according to the characteristics of the steam for steam production, and the external steam pipe network 6 is used for providing external steam.
When the steam drum runs normally, the steam drum 1 continuously discharges continuous sewage from the continuous sewage discharge outlet 11, the continuous sewage enters the primary continuous sewage discharge flash tank 2 through the continuous sewage discharge inlet 21, and primary steam generated by the primary continuous sewage discharge flash tank is discharged from the primary steam outlet 22, mixed with external steam output by the external steam pipe network 6 and then enters the steam ejector 4 through the working steam inlet; the waste hot water produced by the primary continuous blowdown flash tank 2 is discharged from the first blowdown outlet 23 and then enters the secondary blowdown flash tank 3 through the blowdown inlet 31, meanwhile, the periodic blowdown water discharged from the periodic blowdown outlet 12 of the steam drum 1 also enters the secondary blowdown flash tank 3 through the periodic blowdown inlet 32, and the secondary steam produced by the secondary blowdown flash tank 3 is discharged from the secondary steam outlet 33 and then enters the steam ejector 4 through the ejection steam inlet; the secondary steam is raised to the use pressure of the deaerator 5 through the primary steam and the external steam, and the mixed steam is discharged from a mixed steam outlet and then enters the deaerator 5 through a deaerator steam inlet 51 for heating use; the residual steam to be heated in the deaerator 5 is supplemented by external steam output by an external steam pipe network 6. When the steam pocket 1 discharges the sewage regularly, pressure fluctuation is caused due to large instantaneous quantity, and the influence on the pressure of the deaerator 5 is reduced by adjusting the steam quantity of the primary steam and the steam quantity of the external steam.
Therefore, in the energy-saving device in the embodiment, the primary steam produced by the primary continuous blowdown flash tank 2 and the secondary steam produced by the secondary blowdown flash tank 3, which is injected by the steam for heating of the deaerator 5 (namely, external steam), are used for heating the deaerator 5; the heat recovery rate of boiler blow-off water is greatly improved, the working medium recovery rate is improved, the consumption of steam outside the deaerator 5 is reduced, the consumption of production water or circulating water is reduced, the problems of low-grade heat recovery and low-grade heat utilization are solved, and the device has the advantages of energy conservation, consumption reduction, strong operability, safe and reliable system operation, mature and stable equipment, convenience in manufacturing, improvement of enterprise economy and the like.
In a specific implementation manner, considering the requirement of dissolved oxygen and economic efficiency, and effectively improving the heat recovery rate, the energy saving device in this embodiment is mainly applicable to the deaerator 5 at medium pressure and above, and specifically is: when the deaerator 5 is a medium-pressure deaerator, the working pressure is 0.2-0.5 Mpa (G), the pressure in the steam drum 1 is more than or equal to 0.8Mpa (G), the pressure of primary steam output by the primary steam outlet 22 is more than or equal to 0.5Mpa (G), and the pressure of external steam output by the external steam pipe network 6 is more than or equal to 0.5Mpa (G). When the deaerator 5 is a high-pressure deaerator, the working pressure is 0.518mpa (G), the pressure in the steam drum 1 is more than or equal to 5.9mpa (G), the pressure of the primary steam output by the primary steam outlet 22 is more than or equal to 1.0mpa (G), and the pressure of the external steam output by the external steam pipe network 6 is more than or equal to 1.0mpa (G). All pressures mentioned here are gauge pressures.
Preferably, in the design of the steam ejector 4, the total extracted steam amount at the ejected steam inlet in unit time is 1.2-1.5 times the sum of the primary steam amount output in unit time at the primary steam outlet 22 and the secondary steam amount output in unit time at the secondary steam outlet 33, so as to reduce the influence of the instantaneous amount caused by periodic pollution discharge on the outlet pressure of the secondary pollution discharge flash tank 3 (namely the pressure of the secondary steam outlet 33).
The external steam output by the external steam pipe network 6 is preferably superheated steam, and the superheated temperature of the superheated steam is greater than or equal to 5 ℃, so that the efficiency of the steam ejector 4 is improved.
Referring to fig. 2, the steam injector 4 includes at least two stages of injectors 41 connected in series in sequence, each stage of injector 41 having a high pressure steam port 411, a low pressure steam port 412, and a mixed steam port 413, and the mixed steam port 413 of the previous stage of injector 41 is connected to the low pressure steam port 412 of the next stage of injector 41. The plurality of high pressure steam ports 411 constitute a working steam inlet, the low pressure steam port 412 of the first stage ejector 41 constitutes an injected steam inlet, and the mixed steam port 413 of the last stage ejector 41 constitutes a mixed steam outlet. The steam ejector 4 is composed of at least two stages of ejectors 41, the pressure of a mixed steam outlet can be guaranteed to reach the service pressure of the deaerator 5, the deaerator 5 can be guaranteed to stably and normally operate, and waste heat of sewage can be fully recovered.
The single-stage injection coefficient of each stage of injector 41 is greater than or equal to 0.2, and the total amount of steam in unit time of the plurality of high-pressure steam ports 411 (namely the maximum total driving steam amount in unit time of the steam injector 4) is not more than 60% of the gas consumption of the deaerator 5, so as to ensure flexible and stable operation of the deaerator 5.
Further, the working pressure of the secondary pollution discharge flash tank 3 is normal pressure or vacuum pressure, and the operating temperature is more than or equal to 85 ℃; the installation height H (namely the height of the bottom surface of the secondary pollution discharge expansion tank 3 from the ground) is preferably at least 5m at normal pressure, and the installation height H can be determined according to the allowable lifting height at vacuum pressure; within the allowable range of the lifting height of the equipment and the allowable range of the injection coefficient of the injector, the pressure can be reduced to improve the heat and working medium recovery rate.
Further, in order to ensure the safety of the secondary blowdown flash tank 3 in use when a fault occurs, the secondary steam outlet 33 can also be connected on and off with the deaerator steam inlet 51.
More specifically, the continuous blowdown outlet 11 is connected to the continuous blowdown inlet 21 through a continuous blowdown pipe 111, and a continuous blowdown gate valve 1111 is provided on the continuous blowdown pipe 111. The periodic sewage outlet 12 is connected to the periodic sewage inlet 32 through a periodic sewage pipe 121, and a periodic sewage switching valve 12 is provided on the periodic sewage pipe 12111. The first waste water outlet 23 is connected with the waste water inlet 31 through a first waste water pipe 231, a first control valve 2311 is arranged on the first waste water pipe 231, and the opening degree of the first control valve 2311 is controlled by the liquid level in the primary continuous waste water flash tank 2 (a corresponding remote liquid level meter LT is arranged on the primary continuous waste water flash tank 2)1). The second drain outlet 34 is connected to a second drain pipe 341, a second control valve 3411 is provided on the second drain pipe 341, and the second control valve 3411 controls the opening degree of the secondary blowdown flash tank 3 through the liquid level therein (the secondary blowdown flash tank 3 is provided with a corresponding remote level meter LT2) And meanwhile, the secondary pollution discharge flash tank 3 can be ensured not to lose pressure. The secondary steam outlet 33 is connected to the injected steam inlet via a secondary steam pipe 331, and a secondary steam gate valve 3311 and a secondary steam check valve 3312 are provided on the secondary steam pipe 331 (the secondary steam check valve 3312 is located behind the secondary steam gate valve 3311 in the fluid conveying direction).
The primary steam outlet 22 is connected with a primary steam pipe 221, the output end of the external steam pipe network 6 is connected with a first external steam pipe 61 and a second external steam pipe 62, the ends of the primary steam pipe 221 and the first external steam pipe 61 are both connected with the first end of the working steam pipe 222, the second end of the working steam pipe 222 is connected with the working steam inlet (the second end of the working steam pipe 222 is connected with each high-pressure steam port 411), a primary steam gate valve 2211 and a primary steam check valve 2212 are arranged on the primary steam pipe 221 (the primary steam check valve 2212 is positioned behind the primary steam gate valve 2211 in the fluid conveying direction), a third control valve 2221 is arranged on the working steam pipe 222, the opening degree of the third control valve 2221 is controlled by the pressure in the secondary steam pipe 331 (a corresponding remote pressure gauge PT (a PT) is arranged on the secondary steam pipe 331)1). A steam outlet pipe 4131 is connected to the mixed steam outlet, the end of the second outer steam pipe 62 is connected to the deaerator steam inlet 51 through the deaerator steam pipe 511 after communicating with the end of the steam outlet pipe 4131 (the deaerator steam inlet 51 is at least one in number and is connected to the steam outlet pipe 4131), a fourth control valve 621 is provided on the second outer steam pipe 62, and the opening degree of the fourth control valve 621 is controlled by the pressure in the deaerator 5 (the fourth control valve 621 is provided on the second outer steam pipe 5)The deaerator 5 is provided with a corresponding pressure gauge PT2). A steam bypass pipe 332 is also connected to the secondary steam pipe 331, an end of the steam bypass pipe 332 is connected to a steam outlet pipe 4131, and a bypass gate valve 3321 is provided in the steam bypass pipe 332.
In order to ensure the safety of the system, the first control valve 2311, the second control valve 3411, the third control valve 2221 and the fourth control valve 621 are all pneumatic valves, the first control valve 2311 is opened due to air source failure, the second control valve 3411 is opened due to air source failure, the third control valve 2221 is closed due to air source failure, and the fourth control valve 621 is closed due to air source failure. The structure of the pneumatic valve is the prior art, and is driven by instrument wind, wherein the air source fault refers to the fault of the instrument wind; taking the first control valve 2311 as an example, it is always open when the air source is in failure, and when the air source is not in failure, the opening degree can be controlled by the level of the liquid level.
When the third control valve 2221 fails or the steam ejector 4 fails, in order to avoid overpressure of the secondary blowdown flash tank 3, the ejector bypass (i.e., the steam bypass pipe 332) is manually opened to discharge the expansion steam of the secondary blowdown flash tank 3 to the deaerator 5, so that the design pressure of the secondary blowdown flash tank 3 is the same as that of the deaerator 5. That is to say, the working pressure of the secondary blowdown flash tank 3 is adjustable, when the normal operation fails, the working pressure of the secondary blowdown flash tank 3 is smaller than the working pressure (i.e. the service pressure) of the deaerator 5, the pressure of the secondary steam generated by the secondary blowdown flash tank is smaller, lower, even normal pressure or negative pressure, and the driving steam formed by mixing the primary steam and the external steam is required to be lifted and supplied to the deaerator 5; when breaking down, the operating pressure of secondary blowdown flash vessel 3 is the same with the operating pressure of oxygen-eliminating device 5 to guarantee that the back is closed to third control valve 2221, the secondary steam of secondary blowdown flash vessel 3 output can directly supply to oxygen-eliminating device 5 through steam bypass pipe 332, guarantees to continue to retrieve the blow off water heat.
Further, the above-described working steam pipe 222 and secondary steam pipe 331 should be arranged compactly, reducing elbows/reducer sections and valves; the flow velocity of the injected steam inlet is 40-50 m/s, and the flow velocity of the working steam inlet is 20-30 m/s; the flow velocity in the secondary steam pipe 331 is 10-20 m/s, the flow velocity in the steam outlet pipe 4131 is 10-20 m/s, namely the pipe diameter of the secondary steam pipe 331 is determined to be selected according to the flow velocity of 10-20 m/s, the pipe diameter of the steam outlet pipe 4131 is determined to be 10-20 m/s according to the flow velocity, and the pressure loss is reduced while the ejection effect is ensured to the greatest extent.
Further, the working process of the whole energy-saving device is as follows:
in normal operation, the periodic blowdown switching valve 1211 is periodically opened, the bypass gate valve 3321 is closed, the continuous blowdown gate valve 1111 is always opened, the primary steam gate valve 2211 is kept opened, so that the primary steam pipe 221 is communicated with the first external steam pipe 61, and the secondary steam gate valve 3311 is kept opened; the steam drum 1 continuously discharges continuous sewage and enters the primary continuous sewage flash tank 2 through the continuous sewage pipe 111, and the generated primary steam is mixed with the external steam conveyed by the first external steam pipe 61 and then enters the steam ejector 4 through the working steam pipe 222. In order to ensure the steam-water separation effect of the primary continuous blowdown flash tank 2, a certain steam space in the primary continuous blowdown flash tank 2 needs to be ensured, the liquid level needs to be reasonably controlled, waste hot water produced by the primary continuous blowdown flash tank 2 is discharged to the secondary blowdown flash tank 3 through the first drain pipe 231 and the first control valve 2311, secondary steam produced by the secondary continuous blowdown flash tank enters the steam ejector 4 through the secondary steam pipe 331, the secondary steam is lifted to the use pressure of the deaerator 5 by utilizing the primary steam and external steam of the external steam pipe network 6, and enters the deaerator 5 through the steam outlet pipe 4131 for heating use. In order to ensure that the steam-water separation effect of the secondary blowdown flash tank 3 also needs to reasonably control the liquid level, the waste hot water produced by the secondary blowdown flash tank 3 is discharged to the normal pressure system through the second blowdown water pipe 341 through the second control valve 3411.
In order to ensure that the secondary blowdown flash tank 3 is not evacuated or overpressure, a third control valve 2221 is arranged on the working steam pipe 222, and the steam amount of the primary steam and the external steam conveyed by the working steam pipe 222 can be adjusted by controlling the opening degree of the third control valve 2221, so that the working pressure of the secondary blowdown flash tank 3 is adjusted, and the system stability is ensured. The residual steam required by the deaerator 5 is supplemented through an external steam pipe network 6, and specifically, external steam is conveyed to the deaerator 5 through a second external steam pipe 62. In order to ensure the working pressure of the deaerator 5, a fourth control valve 621 is provided on the second external steam pipe 62, and the external steam supply amount delivered by the second external steam pipe 62 can be adjusted by controlling the opening degree of the fourth control valve 621, so as to ensure the working pressure stability of the deaerator 5.
When the steam pocket 1 carries out periodical pollution discharge, the periodical pollution discharge switch valve 1211 is opened, the continuous pollution discharge gate valve 1111 is kept opened, the primary steam gate valve 2211 is kept opened, the secondary steam gate valve 3311 is kept opened, and the bypass gate valve 3321 is kept closed; at the moment, continuous sewage discharge and periodic sewage discharge are carried out simultaneously, and the continuous sewage discharge process is the same as that of the continuous sewage discharge process and is not described again; the periodic sewage is discharged to the secondary sewage flash tank 3 through the periodic sewage discharge pipe 121, the pressure fluctuation is caused by the large instantaneous amount, the steam amount of the primary steam and the external steam conveyed by the working steam pipe 222 is adjusted through the third control valve 2221, and the external steam supply amount conveyed by the second external steam pipe 62 is adjusted through the fourth control valve 621 to reduce the influence on the working pressure of the deaerator 5.
When the third control valve 2221 fails or the ejector fails, the third control valve 2221 is closed, the primary steam is merged into the external steam pipe network 6 through the primary steam pipe 221 and the first external steam pipe 61, and the secondary blowdown flash steam enters the deaerator 5 through the steam bypass by the manual control bypass gate valve 3321.
In summary, the energy saving device in this embodiment has the following advantages:
(1) and (3) heat recovery: in the embodiment, primary steam and steam originally used for heating the deaerator 5 (namely, external steam provided by the external steam pipe network 6) are used as driving steam to inject secondary steam for heating the deaerator 5 at medium pressure and above, so that the heat recovery rate is improved on the premise of no new energy consumption in the process; the heat recovery of the boiler blow-off water of the medium-pressure deoxygenation system can be improved by 20-80%, and the heat recovery accounts for 13-25% of the total blow-off amount; the high-pressure deoxygenation system can be increased by 21-35%, accounts for 16-20% of the total sewage discharge, and reduces the heat loss by about 0.01% -0.04%.
(2) The working medium is recycled and the quality is improved and utilized: compared with a conventional mode or a demineralized water heat exchange scheme, the heat of the primary steam and the steam for heating the deaerator 5 is fully utilized, the pressure energy of the original throttling loss is also utilized as the driving steam for increasing the pressure of the secondary steam, the secondary steam is directly matched to the deaerator pressure through the steam ejector 4 for heating and participating in the whole steam-water circulation, the energy grade is improved, and the throttling loss is reduced; and for secondary steam, the quantity and quality of the secondary steam are recovered while the heat is recovered, when the secondary steam is normal pressure, about 0.1-0.3% of working medium with rated steam production is correspondingly recovered, the steam consumption and the desalted water quantity of the corresponding deaerator 5 are resisted, and the recovery and quality improvement utilization of low-grade steam are effectively realized. The original throttling loss pressure energy means that steam used for heating the deaerator 5 needs to be matched with the steam inlet pressure of the deaerator 5 through the fourth control valve 621 and then enters the deaerator 5, the fourth control valve 621 can guarantee the steam pressure and the steam consumption of the deaerator 5, but throttling loss exists, and the pressure energy is completely lost; according to the method, a part of original throttling loss pressure energy is utilized to promote the secondary steam with lower pressure, the throttling loss of the heating steam is reduced, the recovery rate of the waste water is improved, and the quality improvement and utilization are realized.
(3) Energy conservation, emission reduction and consumption reduction: this embodiment uses the factory as the border, when the flash steam is the ordinary pressure, reduced about 0.1 ~ 0.3% fuel consumption, medium pressure oxygen-eliminating device 5 reduces about 48% production water or circulating water quantity, high pressure oxygen-eliminating device 5 reduces about 60% production water or circulating water quantity, medium pressure oxygen-eliminating device 5 has retrieved 11 ~ 34% total waste water's working medium, compare conventional scheme and reduced about 6 ~ 9% of the outer discharge capacity of waste water, high pressure oxygen-eliminating device 5 has retrieved 15 ~ 32% of the working medium of total waste water, compare conventional scheme and reduced about 6 ~ 8% of the outer discharge capacity of waste water, better energy saving and emission reduction effect has.
(4) In the aspect of economy: the embodiment takes a plant area as a boundary, reduces the fuel quantity, the production water or circulating water consumption, the power consumption caused by the treatment of the external water discharge and the like of daily operation of the plant area by saving energy and reducing consumption, reduces the operation cost, brings certain economic benefit, has small investment and high enterprise investment return rate, and particularly has more remarkable economical efficiency in medium and large-scale devices. After a certain coal chemical engineering project power station is transformed, the cost can be saved by about 115 ten thousand yuan each year, and the investment recovery period is less than 5 months.
(5) And (3) environmental benefit: the embodiment has certain environmental benefit, and through energy saving and consumption reduction, the enterprise can reduce that carbon emission is considerable, can practice thrift 800t mark coal annually after certain coal chemical industry project power station is reformed transform. Meanwhile, the problem of white-fog-around thermal pollution and thermal island effect caused by atmospheric flash evaporation in a plant area is solved, and the operation environment of the plant area is improved.
(6) Operation stability and row fixing advantages: this embodiment is because the relative oxygen-eliminating device 5 steam consumption of secondary steam accounts for than less, and it is undulant to decide to arrange to bring the steam regulating variable to 5 pressure influences of oxygen-eliminating device less, and secondary blowdown flash vessel 3 design pressure has improved operation elasticity space with oxygen-eliminating device 5, has avoided deciding the influence of arranging instantaneous volume to secondary blowdown flash vessel 3.
(7) The method has the advantages of strong optimization operability, low investment, high thermal efficiency, safe and reliable system operation, convenient manufacture and the like. The boiler blow-off energy-saving device is suitable for deaerator 5 at medium pressure and above, is particularly suitable for partial enterprises which can not further recover the heat of blow-off water through desalted water, utilizes the continuously-arranged primary expansion steam and deaerator 5 for heating to inject the secondary expansion steam of the blow-off water of the boiler (namely, the secondary expansion steam is injected by the power steam which is used as steam injector 4 through the primary steam and the external steam) and is used for heating the deaerator 5, makes certain contribution to reducing the energy consumption of the enterprises and reducing the carbon emission, and simultaneously improves the economical efficiency.
The above are merely exemplary embodiments of the present invention, and are not intended to limit the scope of the present invention. Any equivalent changes and modifications that can be made by one skilled in the art without departing from the spirit and principles of the utility model should fall within the protection scope of the utility model.
Claims (13)
1. An economizer apparatus adapted for use in a boiler blow down system, comprising:
a steam drum having a continuous blowdown outlet and a periodic blowdown outlet;
the primary continuous sewage discharge flash tank is provided with a continuous sewage discharge inlet, a primary steam outlet and a first sewage discharge outlet, and the continuous sewage discharge outlet is connected with the continuous sewage discharge inlet in a switching mode;
the secondary pollution discharge flash tank is provided with a pollution discharge water inlet, a periodic pollution discharge inlet, a secondary steam outlet and a second pollution discharge water outlet, the periodic pollution discharge outlet and the periodic pollution discharge inlet can be connected in an on-off manner, and the first pollution discharge outlet and the pollution discharge water inlet can be connected in an on-off manner;
the steam ejector is provided with a working steam inlet, an injected steam inlet and a mixed steam outlet, the primary steam outlet is connected with an external steam pipe network in a switching mode, the primary steam outlet and the external steam pipe network are both connected with the working steam inlet in a switching mode, and the secondary steam outlet is connected with the injected steam inlet in a switching mode;
the deaerator is provided with a deaerator steam inlet, and the mixed steam outlet is connected with the deaerator steam inlet; and the steam inlet of the deaerator is connected with the external steam pipe network in a connection and disconnection manner.
2. The energy saving device for boiler blow-down system according to claim 1,
the deaerator is the middling pressure deaerator, and its operating pressure is 0.2 ~ 0.5Mpa.G, pressure more than or equal to 0.8Mpa.G in the steam pocket, the pressure more than or equal to 0.5Mpa.G of the primary steam of primary steam export output, the pressure more than or equal to 0.5Mpa.G of the outside steam of outside steam pipe network output.
3. The energy saving device for boiler blow-down system according to claim 1,
the oxygen-eliminating device is a high-pressure oxygen-eliminating device, the working pressure of the oxygen-eliminating device is 0.518Mpa.G, the pressure in the steam pocket is more than or equal to 5.9Mpa.G, the pressure of the primary steam output by the primary steam outlet is more than or equal to 1.0Mpa.G, and the pressure of the external steam output by the external steam pipe network is more than or equal to 1.0 Mpa.G.
4. The energy saving device for boiler blow-down system according to claim 1,
the total extraction steam quantity of the injected steam inlet in unit time is 1.2-1.5 times of the sum of the primary steam quantity output in unit time of the primary steam outlet and the secondary steam quantity output in unit time of the secondary steam outlet.
5. The energy saving device for boiler blow-down system according to claim 1,
the external steam output by the external steam pipe network is superheated steam, and the superheated temperature of the superheated steam is more than or equal to 5 ℃.
6. The energy saving device for boiler blow-down system according to claim 1,
the steam ejector comprises at least two stages of ejectors which are sequentially connected in series, each stage of ejector is provided with a high-pressure steam port, a low-pressure steam port and a mixed steam port, and the mixed steam port of the ejector in the previous stage is connected with the low-pressure steam port of the ejector in the next stage; the high-pressure steam ports form the working steam inlet, the low-pressure steam port of the ejector forms the injected steam inlet, and the mixed steam port of the ejector forms the mixed steam outlet.
7. The energy saving device for boiler blow-down system according to claim 6,
the single-stage injection coefficient of each stage of the injector is more than or equal to 0.2, and the total amount of steam in unit time of the high-pressure steam ports is not more than 60% of the gas consumption of the deaerator.
8. The energy saving device for boiler blow-down system according to claim 1,
the working pressure of the secondary pollution discharge flash vessel is normal pressure or vacuum pressure, and the operating temperature of the secondary pollution discharge flash vessel is more than or equal to 85 ℃; and when the working pressure of the secondary pollution discharge flash tank is normal pressure, the height of the bottom surface of the secondary pollution discharge flash tank from the ground is at least 5 m.
9. The energy saving device for boiler blow down system according to claim 1,
the secondary steam outlet can be connected with the steam inlet of the deaerator in a connection and disconnection mode.
10. The energy saving device for boiler blow-down system according to claim 9,
the continuous sewage discharge outlet is connected with the continuous sewage discharge inlet through a continuous sewage discharge pipe, and a continuous sewage discharge gate valve is arranged on the continuous sewage discharge pipe;
the periodic blowdown outlet is connected with the periodic blowdown inlet through a periodic blowdown pipe, and a periodic blowdown switch valve is arranged on the periodic blowdown pipe;
the first sewage draining outlet is connected with the sewage draining inlet through a first sewage draining pipe, a first control valve is arranged on the first sewage draining pipe, and the opening degree of the first control valve is controlled by the liquid level in the primary continuous sewage draining flash tank;
a second sewage discharge pipe is connected at the second sewage discharge outlet, a second control valve is arranged on the second sewage discharge pipe, and the opening degree of the second control valve is controlled by the liquid level in the secondary sewage discharge flash tank;
the secondary steam outlet is connected with the injected steam inlet through a secondary steam pipe, and a secondary steam gate valve and a secondary steam check valve are arranged on the secondary steam pipe;
the primary steam outlet is connected with a primary steam pipe, the output end of the external steam pipe network is connected with a first external steam pipe and a second external steam pipe, the end parts of the primary steam pipe and the first external steam pipe are both connected with the first end of a working steam pipe, the second end of the working steam pipe is connected with the working steam inlet, a primary steam gate valve and a primary steam check valve are arranged on the primary steam pipe, a third control valve is arranged on the working steam pipe, and the opening degree of the third control valve is controlled by the pressure in the secondary steam pipe;
a steam outlet pipe is connected to the mixed steam outlet, the end of the second outer steam pipe is communicated with the end of the steam outlet pipe and then is connected with the steam inlet of the deaerator through a deaerator steam pipe, a fourth control valve is arranged on the second outer steam pipe, and the opening degree of the fourth control valve is controlled through the pressure in the deaerator;
a steam side pipe is also connected to the secondary steam pipe in a side manner, the end part of the steam side pipe is connected to the steam outlet pipe in a side manner, and a bypass gate valve is arranged on the steam side pipe.
11. The energy saving device for boiler blow down system according to claim 10,
the first control valve, the second control valve, the third control valve and the fourth control valve are pneumatic valves, the first control valve is opened for air source failure, the second control valve is opened for air source failure, the third control valve is closed for air source failure, and the fourth control valve is closed for air source failure.
12. The energy saving device for boiler blow down system according to claim 11,
and when the third control valve fails or the steam ejector fails, the design pressure of the secondary blowdown flash tank is the same as that of the deaerator.
13. The energy saving device for boiler blow down system according to claim 10,
the flow velocity of the injected steam inlet is 40-50 m/s, and the flow velocity of the working steam inlet is 20-30 m/s; the flow velocity in the secondary steam pipe is 10-20 m/s, and the flow velocity in the steam outlet pipe is 10-20 m/s.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN115301078A (en) * | 2022-06-30 | 2022-11-08 | 华电电力科学研究院有限公司 | Denitration system for pyrolyzing urea by utilizing energy of exhaust-heat boiler blowdown system |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115301078A (en) * | 2022-06-30 | 2022-11-08 | 华电电力科学研究院有限公司 | Denitration system for pyrolyzing urea by utilizing energy of exhaust-heat boiler blowdown system |
| CN115301078B (en) * | 2022-06-30 | 2023-06-23 | 华电电力科学研究院有限公司 | Utilize exhaust-heat boiler drain energy pyrolysis urea's deNOx systems |
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