RU2012829C1 - Regenerative heater of feeding water of ejector - Google Patents

Abstract

FIELD: heat power engineering. SUBSTANCE: active water ring nozzle encloses active water nozzles. A mixing chamber provided with inlet branch pipe is separated into sections for supplying condensed vapor of different parameters. Walls of the section within the mixing chamber are made of hollow funnel-shaped diaphragms which are converged in the direction of heater outlet and oriented in the direction of flow. Outlet section of the diaphragms is made of an auxiliary active water ring nozzles. Inner diameter of diaphragms in the zone of their outlet section is determined by a given relationship. A directing unit is mounted in the section and made of an assemble of funnel-shaped nozzles provided with flexible tips at their ends. Inner diameter of the outlet section of the nozzles does not exceed inner diameter of the outlet section of the diaphragm located downstream of the assemble. Vanes are mounted at an angle to nozzle axis at outlet part of the main nozzle. EFFECT: enhanced efficiency. 3 cl, 4 dwg

Description

 The invention relates to steam turbine construction and can be used in heat engineering.

 A multi-jet condenser is known in which cooling water supplied by a separate pump flows from the nozzles at high speed in continuous discrete jets. In the receiving chamber, intermediate cones are installed, forming many channels through which the spent steam enters the mixing chamber. The steam, in contact with the surfaces of the jets, condenses, and air and other non-condensable gases are carried away by friction on the outer surfaces of the jets. After this, jets of heated water with the air carried by them enter the diffuser. The operation of the ejector capacitor is the more effective, the greater the ratio of the perimeter of each jet to its cross-sectional area and the smaller the diameter of the jet. However, an increase in the number of jets is advisable only to a certain limit, since with a decrease in nozzle diameter, losses in them increase. The advantages of an ejector capacitor are compactness, simplicity of the device.

 This known technical solution has the following disadvantages: limited use - suitability for condensation of only one flow of exhaust steam due to the inability to create sealed sections for discrete streams of water for steam flows with different parameters; if supplying such a condenser through the corresponding channels of steam flows with different parameters in the displacement chamber of the latter, a certain average pressure would be established for all steam flows, which would lead to the shutdown of regenerative samplings having pressures lower than the indicated average pressure; large hydraulic losses due to the installation of a displacer in the center of the capacitor, on which the water jets rub, and also due to the installation of a large number of intermediate cones; as experiments have shown when working in cold water, it is optimal to install three intermediate cones for one steam stream; no measures are provided to maintain the stability of the device in partial and transient modes.

 A multi-jet injector-condenser of a steam turbine installation is known, containing a central active steam nozzle, a confuser displacement chamber and peripheral nozzles for supplying a passive medium, the area of each of which is 0.0265. . . 0.0275 of the output section area of the active nozzle, while the mixing chamber has a length of 6.15. . . 6.3 its equivalent diameters.

 This known technical solution has the following disadvantages: limited use - suitability for condensation of only one stream of saturated steam; no measures are provided to maintain the stability of the device in partial and transient modes.

 Known multi-jet ejector capacitor containing an active nozzle for heating steam, active water nozzles, a displacement chamber with a pipe for supplying condensable steam and a diffuser.

 The condenser has the following disadvantages: limited use - unsuitable for condensation of several steam streams from the steam turbine offsets simultaneously, having different pressures and different degrees of overheating; no measures are provided to maintain the stability of the device in partial and transient modes.

 The purpose of the invention is to increase the efficiency of regenerative heating of feed water of a steam turbine plant.

- tg

, где D_gi - внутренний диаметр i-й диафрагмы в ее выходном сечении, м;
D_o - средний диаметр основного активного водяного кольцевого сопла в его выходном сечении, м;
d₃ - внутренний диаметр цилиндрического участка камеры смешения, м;
l_ci - расстояние между срезами основного и i-го вспомогательного активного кольцевого водяного сопла, м;
L - расстояние от среза основного водяного кольцевого сопла до середины цилиндрического участка камеры смешения, м;
Р_р - давление рабочей воды перед основным кольцевым водяным соплом, Па;
Р_н.п. - наименьшее давление инжектируемого пара, например из последнего отбора турбины, Па;
d_ро - калибр основного водяного кольцевого сопла, м;
d_ро =

, где f_ро - площадь выходного сечения основного кольцевого водяного сопла, м₂; подогреватель снабжен по меньшей мере одним направляющим устройством, установленным в виде пакета, по крайней мере из двух воронкообразных насадок с эластичными наконечниками на конце, при этом внутренний диаметр выходного сечения насадок не превышает внутренего диаметра выходного сечения расположенной за пакетом диафрагмы; основное водяное кольцевое сопло в его выходной части снабжено лопатками, установленными под углом к оси сопла.This is achieved by the fact that an ejector-type regenerative feedwater heater containing an active nozzle for heating steam, active water nozzles, a bias chamber with a condensate steam supply pipe and a diffuser is equipped with an active ring water nozzle covering active water nozzles, and a bias camera with a supply pipe is divided at least two sections for supplying condensable steam flows of different parameters, while in the displacement chamber the walls of the sections are made in the form of hollow funnel-shaped diaphragms, tapering I towards the exit from the heater and oriented in the direction of flow, and the output section of the funnel-shaped diaphragms is made in the form of auxiliary active water annular nozzles and the inner diameter of the diaphragms in the area of their output section is determined from the mathematical expression
D _gi = D ₀ + d _ro -2l

- tg

where D _gi is the inner diameter of the i-th diaphragm in its output section, m;
D _o - the average diameter of the main active water annular nozzle in its output section, m;
d ₃ - the inner diameter of the cylindrical section of the mixing chamber, m;
l _ci is the distance between the slices of the main and i-th auxiliary active ring water nozzle, m;
L is the distance from the slice of the main water annular nozzle to the middle of the cylindrical portion of the mixing chamber, m;
R _p is the pressure of the working water in front of the main annular water nozzle, Pa;
R _n.p. - the lowest pressure of the injected steam, for example, from the last turbine extraction, Pa;
d _ro - caliber of the main water ring nozzle, m;
d _ro =

where f _ro - the area of the output section of the main annular water nozzle, m ₂ ; the heater is equipped with at least one guide device installed in the form of a packet of at least two funnel-shaped nozzles with elastic tips at the end, while the inner diameter of the outlet section of the nozzles does not exceed the inner diameter of the outlet section located behind the packet of the diaphragm; the main water annular nozzle in its output part is provided with blades mounted at an angle to the axis of the nozzle.

 In FIG. 1 shows the proposed heater; in FIG. 2 is a section AA in FIG. 1; in FIG. 3 - node I in FIG. 1; in FIG. 4 is a diagram of the relationship of the basic geometric parameters of the regenerative heater.

 The regenerative heater comprises a housing 1, a water chamber 2, a mixing chamber 3, a multi-section pipe 4 for supplying condensable steam flows of different parameters, an active nozzle 5 for heating steam, active water nozzles 6 located around the circumference around the nozzle 5, the main active water ring nozzle 7 with blades 8, hollow funnel-shaped diaphragms 9 with nozzles 10 and outlet sections 11 turning into auxiliary active water annular nozzles 12, guiding devices made in the form of a package of funnel-shaped nozzles to 13 with elastic tips 14, a displacement chamber 15 of a cylindrical type with a confuser inlet and a diffuser 16.

 The nozzle 7 is equipped with blades 8 mounted at an angle to the axis.

 A package of funnel-shaped nozzles 13 with elastic tips 14 is fastened to the diaphragm 9 using studs 17 and intermediate sleeves 18.

In FIG. 4 shows a diagram of the relationship of the basic geometric parameters of the regenerative heater. Here are displayed:
D _gi is the inner diameter of the i-th diaphragm in its output section;
D _o - the average diameter of the main active water annular nozzle in its output section;
d ₃ - the inner diameter of the cylindrical section of the displacement chamber;
l _ci is the distance between the slices of the main and i-th auxiliary active water ring nozzle;
L is the distance from the slice of the main water annular nozzle to the middle of the cylindrical section of the displacement chamber;
d _ro - caliber of the main water ring nozzle.

 Regenerative heater operates as follows.

Heated condensate (feed water) is supplied under pressure, for example, by a condensate pump, to a chamber 2 built into the housing 1, from which it enters the nozzles 6 and 7. In the latter, the potential energy of the condensate working stream is converted into kinetic energy of the jets, which carry the streams the steam entering the pipe section 4 from the turbine take-offs. In this case, passive steam flows with higher pressures flow into sections closer to the cylindrical displacement chamber 15 with a confuser inlet. In order to prevent steam from flowing from the section with higher pressure to the section with lower pressure, a hollow cone-shaped condensate stream is formed with the help of a water ring nozzle 7, and hollow diaphragms 9 with water ring auxiliary nozzles 12 (diaphragm nozzles) are adjacent to the outer surface. Condensate is supplied to the latter through the nozzles 10 along the cavities in the diaphragms 9. The annular jets flowing from the nozzles 12 are directed along the surface of the specified hollow cone-shaped jet, covering the latter from the outside, and give it additional kinetic energy, preventing its erosion and stabilizing the ejection process. In addition, this creates the necessary seals between the sections of the mixing chamber 3 with passive steam flows. These circumstances provide an ejection of at least one of two steam streams having different parameters. To maintain tightness between adjacent sections of the mixing chamber, it is sufficient to fulfill the conditions
P $\genfrac{}{}{0ex}{}{\text{aux}}{\text{dean}}$ _i ≥ ΔP _stati , where P $\genfrac{}{}{0ex}{}{\text{aux}}{\text{dean}}$ _i is the dynamic pressure of the i-th auxiliary water annular jet created using the corresponding diaphragm nozzle;
ΔP _stati is the differential pressure at the boundary between the corresponding adjacent sections.

 As a result of this, as well as due to the energy consumption of the main and auxiliary water ring jets (from nozzle 7 and nozzle 12), discrete water jets (from nozzle 6) and steam jet (from nozzle 5), the distribution of the passive steam flows in the mixing chamber is established static pressures increasing to its outlet, while maintaining different pressure gradients at the boundaries between adjacent sections, which leads to the separation of the main and annular water jet moving and interacting with steam flows of different parameters into autonomous e compartments. At the same time, the temperature of the working (nutrient) water increases as it moves toward the exit from the heater. However, experiments show that an increase in the temperature of water does not affect its ejection ability, while the ratio of the pressure at the inlet to the cylindrical section of the mixing chamber to the pressure of the injected steam is practically independent of its temperature, although the pressure recovery at the outlet of the heater decreases. However, in the proposed heater, additional pulses supplied from the remaining jets lead to an increase in the static pressure of the heated feed water (condensate) in the cylindrical section of the mixing chamber 15, where the steam condensation process is completed, and then in the diffuser 16.

The pressure ratio P _2i / P _ni / P _2i is the pressure of the medium in the region of the cutoff of the corresponding diaphragm nozzle 12, P _ni is the pressure of the injected vapor in the corresponding section of the supply chamber 4 is mainly controlled by the flow of water through the nozzles 6 and 7, and they are adjusted by supplying the corresponding amount of water through the nozzle orifice 12. since in this case the ratio P _2i / P _HI does not depend on the pressure of the injected steam P _HI, the inlet pipe section sequentially injected steam 4 flows with increasing pressure values _HI P in any case does not lead to homogenization pressures of all the sections of the mixing chamber. As a result, in the proposed regenerative heater, condensation of steam flows in an overheated state occurs, since the stream of superheated steam is previously compressed, moving from one section to another, to a higher pressure at which it becomes saturated at a given temperature. In order to condense steam with a high degree of overheating, it is necessary to first reduce its degree of overheating by cooling it in some kind of additional heat exchanger. High superheating of the steam is usually achieved in the selection of medium and high pressure turbines.

 In order for each of the passive steam flows in the sections of the displacement chamber 3 to be uniformly distributed in the form of thin layers on the corresponding sections of the outer surface of the hollow cone-shaped water jet, guide devices are used, made in the form of a package of funnel-shaped nozzles 13 with elastic tips 14. In this case, the elastic tips 14 act as non-return valves and prevent the occurrence of return flows of passive steam within each section, and also act as dampers. These return flows usually appear due to weakening of the ejection ability of water jets, due to inevitable pressure pulsations during steam condensation on the surface of water jets, and also due to the presence of gaps between water jets and guiding devices, which increase during operation in partial and variable modes, when geometric characteristics change jets. Instead of the elastic tips 14, flap valves or tips in the form of orifice plates can be used.

 To improve the mixing of steam with condensate (feed water), the hollow cone-shaped jet is twisted using blades 8. In addition, the swirling of the hollow jet leads to the appearance of centrifugal forces, which press the jet to the auxiliary ring jets, which are formed sequentially along the main stream, which prevents erosion of the latter.

 Then, in order to increase the degree of heating of the condensate (feed water) and to further increase the ejection ability of the device, heating steam is supplied through the central active nozzle 5, coming from a turbine with the highest steam parameters, or cooled steam from the boiler. The generated steam jet transfers additional kinematic energy to the working jets of the conedsat from the inside of the two-layer multi-jet structure formed by nozzles 6 and 7, and in addition, it heats the jets of the specified structure in contact with them. To increase the contact surface, the inner cone of the specified multi-jet structure, framing the steam jet, is formed using a large number of ordinary continuous condensate jets created by nozzles 6. After this, the resulting mixture of condensate and partially non-condensing steam enters the cylindrical section of the mixing chamber 15, where the steam finally condenses, and the heated condensate enters the diffuser 16. Having passed the diffuser, the flow of condensate (feed water) increases its pressure and is directed to consume ate or in the deaerator.

 The proposed technical solution took all measures to eliminate the shortcomings that exist in all known technical solutions: only two funnel-shaped nozzles were used to condense a single steam stream, not more of them (as is done in a multi-jet condenser), which reduces hydraulic losses, but at the same time, it facilitates the compression of the condensing vapor to the surface of the main water stream and thereby improves the heat transfer between them; the gaps between the discrete solid water jets and the ejected vapor stream are eliminated by the use of a continuous hollow main water jet and the compression of the condensed steam flows to the surface of the latter; return stall flows of steam within the mixing chamber and its sections are eliminated through the use of respectively sealing auxiliary water ring jets and elastic tips; the number of discrete water jets is limited, since their increase is advisable only to a certain limit.

 Thus, the measures taken increase the efficiency of the ejector type heater and ensure the stability of the processes occurring in it in comparison with the known heaters.

 The effectiveness of the proposed technical solution increases further due to the fact that it essentially combines several single-stage indicated known heaters for condensing several steam streams with different parameters. This combination has led to a sharp decrease in the number of pumps, heat exchangers and pipelines in the system of regenerative heating of feed water, and consequently, to a significant reduction in hydraulic losses and the cost of equipment.

 Based on the foregoing, the use of the claimed technical solution provides a reduction in the size and cost of the regenerative heating system of feed water of a steam turbine unit due to the compact arrangement of at least two sections-heaters in one device, due to the intensification of heat transfer, due to an increase in the contact surface of heat-exchange media; increasing the stability of the processes in the heater by maintaining a high ejection effect, uniform throughout the device, due to the uniform distribution of passive media within the sections with the exception of the return flow of media between the sections and within the sections of the mixing chamber. (56) Copyright certificate of the USSR N 872797, cl. F 04 F 5/02, 1978.

Claims (3)

1. REGENERATIVE HEATER OF EJECTOR TYPE WATER HEATER containing an active nozzle for heating steam, active water nozzles, a mixing chamber with a nozzle for supplying condenser steam and a diffuser, characterized in that the heater is equipped with an active water ring nozzle covering the active water nozzles, and a mixing chamber the supply is divided into at least two sections for supplying condensable steam flows of different parameters, while in the mixing chamber the walls of the sections are made in the form of hollow funnel-shaped diaphragms um, tapering towards the outlet of the preheater and oriented in the flow direction, and the output of funnel-shaped aperture portion is formed as a support ring of active water nozzles and an inner diameter of the diaphragms in the area of the outlet section is determined from the mathematical expression
D

= D ₀ + d

-2l

- tg

where D _di - the inner diameter of the i-th diaphragm in its output section, m;
D ₀ - the average diameter of the main active water annular nozzle in its output section, m;
d ₃ - the inner diameter of the cylindrical section of the mixing chamber, m;
l _ci is the distance between the slices of the main and i-th auxiliary active ring water nozzles, m;
L is the distance from the slice of the main water annular nozzle to the middle of the cylindrical portion of the mixing chamber, m;
P _p - pressure of the working water in front of the main annular water nozzle, Pa;
P _np - the lowest pressure of the injected steam, for example, from the last turbine extraction, Pa;
d _P0 - caliber of the main water annular nozzle, m,
d

=

,
where f _P0 is the area of the output section of the main annular water nozzle, m ² .  2. The heater according to claim 1, characterized in that it is equipped with at least one guide device installed in the section and made in the form of a packet of at least two funnel-shaped nozzles with elastic tips at the end, while the inner diameter of the outlet section of the nozzles is not exceeds the inner diameter of the output section located behind the package diaphragm.  3. The heater according to claim 1, characterized in that the main water annular nozzle in its output part is provided with blades mounted at an angle to the axis of the nozzle.

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