CN201434624Y

CN201434624Y - Combined heat exchanger with multiple phase change units

Info

Publication number: CN201434624Y
Application number: CN2009200913230U
Authority: CN
Inventors: 张志宇
Original assignee: Individual
Current assignee: Individual
Priority date: 2009-07-06
Filing date: 2009-07-06
Publication date: 2010-03-31
Anticipated expiration: 2019-07-06

Abstract

The utility model relates to a combined heat exchanger with multiple phase change units, which comprises an upper header, a lower header, and independent single phase change units communicated with heat exchange pipes, wherein an inner chamber and two outer chambers are formed in the upper header via tube plates, a tube penetrates the inner chamber and is provided with openings in the two outer chambers, the inner chamber of the upper header is communicated with the heat exchange pipes, a liquid over flow needle valve is mounted on the heat exchange pipes between the inner chamber of the upperheader and the lower header, a needle valve for pollution discharge is arranged on the lower header, a branch pipe is connected between the outer chambers of the upper header and the inner chamber thereof, a liquid spherical valve and an exhaust needle valve are mounted on the branch pipe, and an exhaust spherical valve is mounted on the pipelines between the liquid spherical valve and the exhaust needle valve; the upper header, a water inflow header and a water outlet header are connected in parallel into the combined heat exchanger with multiple phase change units between the independent single phase change units, the minimum wall temperature of the tail heating surface of a boiler is controlled higher than the flue gas acid dew point, and the stack gas temperature is reduced to 15 DEGC higher than the minimum wall temperature of the heat-exchange surface; and the combined heat exchanger can be arranged not only in a horizontal flue but also in a vertical flue. Therefore, the combined heat exchanger is flexible in structural design and layout, and conserves space.

Description

Combined heat exchanger with multi-phase change units

Technical field

The utility model relates to a kind of alternative tubular type, heat exchange of heat pipe and complex phase-change heat exchanger, when the lowermost wall surface temperature of heated surface at the end of boiler can be controlled at automatically more than the flue gas acid dew point, exhaust gas temperature can be reduced to only than high about the 15 ℃ combined heat exchanger with multi-phase change units of heating surface control minimum wall temperature.

Background technology

As everyone knows, owing to SO in the boiler smoke ₃Existence, the exit gas temperature of back-end surfaces air preheater is restricted.Exhaust gas temperature is low excessively, will cause serious dewing corrosion taking place with stifled grey because heating surface lowermost wall surface temperature is lower than flue gas acid dew point.So the boiler design exhaust gas temperature can not be low excessively, the design exhaust gas temperature of tubular air preheater is usually at 140 ℃～160 ℃ or higher; The design exhaust gas temperature of rotary regenerative air preheater is usually at 130 ℃～140 ℃.Even if like this, the corrosion of heating surface and clogging phenomenon are still unavoidable.The lowermost wall surface temperature of rotary regenerative air preheater is controlled at more than the flue gas water dew point usually, so ubiquity cold end corrosion in various degree.So-called its has stronger anti-cold end corrosion, be meant that cold end corrosion can heat exchanging not cause tangible influence in to a certain degree, but the bigger additional energy consumption of being brought of leaking out is that it can't overcome one's shortcomings, and the recovery flue gas heat is lacking flexibility than tubular air preheater aspect the distribution of feedwater and air-supply.Complex phase-change heat exchanger can reduce exhaust gas temperature significantly under the prerequisite of keeping higher lowermost wall surface temperature, only can effectively exhaust gas temperature be controlled at higher about 15 ℃ (when for example controlling 100 ℃ of wall temperatures than lowermost wall surface temperature, about 115 ℃ of exhaust gas temperatures), can under the prerequisite of face generation cold end corrosion that keeps from heat, reduce exhaust gas temperature significantly.But,, limited its space and can arrange scope because reasons in structure phase transformation section heating surface must be arranged on the horizontal flue.

Summary of the invention

The purpose of this utility model is to overcome the deficiencies in the prior art and provides a kind of and guaranteeing that back-end surfaces is not under the prerequisite of dewfall, reclaim fume afterheat by the method that reduces exhaust gas temperature, and the heat that reclaims is used to heat low-pressure low-temperature water, the boiler air-supply, to improve the steam generator system thermal efficiency and to utilize the combined heat exchanger with multi-phase change units of boiler afterheat, it is that unit forms a plurality of independently phase change cells with the heat exchanger tube row perpendicular to the flow of flue gas direction, each phase change cells is by endotherm section (evaporator section), heat release section (condensation segment) is formed, by the heat-transfer surface form of preferred arrangement endotherm section and heat release section, structure and heat exchange area obtain needed minimum control wall surface temperature.

The purpose of this utility model is achieved in that and comprises upper header, lower collector pipe and be connected upper header, the single phase change cells of independence that each heat exchanger tube between the lower collector pipe becomes airtight integral body to become by inner chamber UNICOM, it is characterized in that: in independent single phase change cells, the tube sheet that is provided with by two in the inside of upper header forms two exocoels at an inner chamber and two, in this inner chamber, passed tubulation, the opening of tubulation is arranged in two exocoels at two, the inner chamber of upper header and each heat exchanger tube are connected, on the heat exchanger tube of connecting between the inner chamber of upper header and the lower collector pipe, topping up overflow needle valve is installed also, lower collector pipe is provided with the blowdown needle valve, between the inner chamber of the pipeline of the exocoel that leads to upper header and upper header, connect arm is arranged, topping up ball valve and exhaust needle valve are installed on this arm, on the pipeline between topping up ball valve and the exhaust needle valve, venting ball valve are installed; The composition combined heat exchanger with multi-phase change units is connected in parallel after connecting by upper header and water inlet collector and water outlet collector between described each independent single phase change cells.

Temperature measurer is installed between upper header, is provided with from control regulation valve on the bypass water route that is connected with water inlet collector and water outlet collector, temperature measurer is connected with self-con-tained unit, self-con-tained unit be connected from control regulation valve.

Each upper header is formed becomes endotherm section lowermost wall surface temperature phase change cells together.

The utlity model has the key property of complex phase-change heat exchanger, when the lowermost wall surface temperature of heated surface at the end of boiler can be controlled at automatically more than the flue gas acid dew point, exhaust gas temperature can be reduced to only high about 15 ℃ than heating surface control minimum wall temperature.The more important thing is that it promptly can be arranged in horizontal flue, also can be arranged in vertical gas pass, increased structural design and on-the-spot flexibility of arranging greatly, save the production area usage space.

Description of drawings

Fig. 1 is a single phase change cells structural representation of the present utility model.

Fig. 2 is a combined heat exchanger with multi-phase change units structure diagram of the present utility model.

The specific embodiment

As Fig. 1, shown in 2, the utility model comprises upper header 6, lower collector pipe 2 and be connected upper header 6, the single phase change cells 14 of independence that each heat exchanger tube 3 of some between the lower collector pipe 2 and specification becomes airtight integral body to become by inner chamber UNICOM, it is characterized in that: in independent single phase change cells 14, the tube sheet 4 that is provided with by two in the inside of upper header 6 forms two exocoels at an inner chamber and two, in this inner chamber, passed tubulation 5, the opening of tubulation 5 is arranged in two exocoels at two, the inner chamber of upper header 6 and each heat exchanger tube 3 are connected, on the heat exchanger tube of connecting between the inner chamber of upper header 6 and the lower collector pipe 2, topping up overflow needle valve 10 is installed also, lower collector pipe 2 is provided with blowdown needle valve 1, between the inner chamber of the pipeline of the exocoel that leads to upper header 6 and upper header 6, connect arm is arranged, topping up ball valve 9 and exhaust needle valve 7 are installed on this arm, on the pipeline between topping up ball valve 9 and the exhaust needle valve 7, venting ball valve 8 are installed; The composition combined heat exchanger with multi-phase change units is connected in parallel after connecting by upper header 6 and water inlet collector 15 and water outlet collector 16 between described each independent single phase change cells 14.Temperature measurer 11 is installed between upper header 6, is provided with from control regulation valve 9 on the bypass water route 13 that is connected with water inlet collector 15 and water outlet collector 16, temperature measurer 11 is connected with self-con-tained unit 12, self-con-tained unit 12 be connected from control regulation valve 9.

Connect into the airtight integral body of an inner chamber UNICOM by the heat exchanger tube 3 of last

lower collector pipe

6,2 and some and specification, promptly independent single phase change cells 14.For the needs of topping up and exhaust, be provided with blowdown needle valve 1, exhaust needle valve 7, topping up ball valve 9, venting ball valve 8 and topping up overflow needle valve 10 specially.The heat exchanger tube 3 of some and specification is formed the endotherm section (evaporator section) of phase change cells; The double tubular heat exchanger of doing of upper header is made up of tubulation 5, tube sheet 4 and housing, is referred to as heat release section (condensation segment).The heat release section tube side is by needing the condensate water or the demineralized water (soft water) of heating, shell side and heat exchanger tube UNICOM.The single phase change cells of some is combined, be arranged in the main part of just having formed combined heat exchanger with multi-phase change units in horizontal flue or the vertical gas pass, be equipped with from control regulation valve, temperature measurer and self-con-tained unit and finally form combined heat exchanger with multi-phase change units.

By optimizing the heat exchanger area that distributes each phase change cells heat release section, realize the different wall surface temperature designs of each phase change cells endotherm section, and wherein the wall temperature of certain phase change cells endotherm section is designed to minimum relatively.When system moves, as long as the wall surface temperature of control endotherm section lowermost wall surface temperature phase change cells 14 is higher than the control temperature, just can control whole combined heat exchanger with multi-phase change units endotherm section lowermost wall surface temperature and be higher than flue gas acid dew point, avoid the generation of device cold end corrosion.At the vapor phase space of endotherm section lowermost wall surface temperature phase change cells (upper header) temperature measurer 11 is installed, 13 are provided with from control regulation valve 9 in the bypass water route, and the heat release section tube side of each phase change cells is in parallel or be connected in series.Structure shown in Figure 2 is for being arranged in horizontal flue, the combined heat exchanger with multi-phase change units of heat release section tube side parallel connection.In the time of in being arranged in vertical gas pass, only need make each phase change cells and horizontal plane angled, last lower collector pipe has certain height difference, relies on gravity to realize reliable Natural Circulation to guarantee phase change cells intraluminal fluid attitude phase transformation medium.

Running is as follows: before the device operation, at first pass through topping up ball valve 9 to each phase change cells topping up, filling amount is by 10 controls of topping up overflow needle valve.Topping up finishes and can carry out exhaust.During exhaust, regulate earlier the internally piloted valve aperture, make endotherm section lowermost wall surface temperature be higher than 100 ℃, open exhaust needle valve 7 then and venting ball valve 8 carries out exhaust, continue approximately to get final product in 5～10 minutes.Be in operation, on-condensible gas occur in the phase transformation chamber and assemble influence and rerun after heat-transfer effect or system shutdown overhaul, all need repeat aforesaid operations, to reach best heat exchange effect.Flue gas is by endotherm section, and heat transfer agent is seethed with excitement after absorbing heat in the phase change cells, promptly undergoes phase transition.The steam that produces rises and enters the heat release section shell side and carry out heat exchange with the water of its tube side, and steam condenses by gravity reflux to endotherm section (or lower collector pipe), and heat exchange is carried out in the phase transition process of continuous evaporation and condensation.Because certain medium has constant phase transition temperature under given pressure, the heat exchange amount of regulating heat release section can change the pressure in the phase change cells, so the discharge that enters heat release section by change can be regulated the endotherm section wall surface temperature of this phase change cells.This device is at first set the minimum design wall temperature of endotherm section lowermost wall surface temperature phase change cells 14, need the condensate water of heating or demineralized water (soft water) enters each phase change cells through water inlet collector 15 heat release section, be sent to oxygen-eliminating device after being pooled to water outlet collector 16 after absorption heat temperature raises, the temperature signal that temperature measurer 11 records feeds back to self-con-tained unit, self-con-tained unit 12 is regulated the aperture from control regulation valve 9 on the bypass water route 13 automatically, and feasible minimum wall temperature with phase change cells 14 of minimum design wall temperature is in setting value all the time.Like this, the lowermost wall surface temperature of whole device is higher than setting value (flue gas calculation dew point) all the time, thereby has stopped the generation of low temperature acid corrosion.

Claims

1, a kind of combined heat exchanger with multi-phase change units, comprise upper header (6), lower collector pipe (2) and be connected upper header (6), the single phase change cells of independence (14) that each heat exchanger tube (3) between the lower collector pipe (2) becomes airtight integral body to become by inner chamber UNICOM, it is characterized in that: in independent single phase change cells, the tube sheet (4) that is provided with by two in the inside of upper header (6) forms two exocoels at an inner chamber and two, in this inner chamber, passed tubulation (5), the opening of tubulation (5) is arranged in two exocoels at two, the inner chamber of upper header (6) and each heat exchanger tube (3) are connected, on the heat exchanger tube of connecting between the inner chamber of upper header (6) and the lower collector pipe (2), topping up overflow needle valve (10) is installed also, lower collector pipe (2) is provided with blowdown needle valve (1), between the inner chamber of the pipeline of the exocoel that leads to upper header (6) and upper header (6), connect arm is arranged, topping up ball valve (9) and exhaust needle valve (7) are installed on this arm, on the pipeline between topping up ball valve (9) and the exhaust needle valve (7), venting ball valve (8) are installed; Between described each independent single phase change cells (14) by the composition combined heat exchanger with multi-phase change units that is connected in parallel after upper header (6) and water inlet collector (15) and water outlet collector (16) connection.

2, combined heat exchanger with multi-phase change units according to claim 1, it is characterized in that: temperature measurer (11) is installed between upper header (6), go up setting from control regulation valve (9) in the bypass water route (13) that is connected with water inlet collector (15) and water outlet collector (16), temperature measurer (11) is connected with self-con-tained unit (12), self-con-tained unit (12) be connected from control regulation valve (9).