VACUUM CONDENSATION SYSTEM BY USING EVAPORATIVE CONDENSER AND AIR REMOVAL SYSTEM COUPLED TO CONDENSING TURBINES IN THERMOELECTRIC PLANTS

Abstract

A VACUUM CONDENSATION SYSTEM BY USING EVAPORATIVE CONDENSER AND AIR REMOVAL SYSTEM COUPLED TO CONDENSING TURBINES IN THERMOELECTRIC PLANTS, made of stainless steel, metal alloys or other materials. This condensing system includes an evaporative condenser, air removal ejector system and condensers, turbine exhaust steam collector system with pipelines, collection and return systems of the condensate to the boiler. The exhaust steam generated in the turbine is driven by steam collector system, condensed in the evaporative condenser, and the air is removed from the system by the air removal (ejectors) and the condensed air is returned to the boiler by the condensed system.

Claims

1-8. (canceled)

9. Vacuum condensation system by using evaporative condenser and air removal system coupled to condensing turbines in thermoelectric plants, comprising: a vacuum condensation system formed from stainless steel and further comprising an exhaust steam collector, a steam duct, an evaporative condenser, ejectors and ejectors condensers; wherein the steam duct is suspended by supports and collects the exhaust steam from the condensing turbine through the steam collector; the exhaust steam already at low pressure is led to the evaporative condenser, where the steam is into condensed water which is done with the aid of the recirculating water; the turbine exhaust steam passes through the duct and is distributed by the ducts in the steam input chamber, distributed in the tubular pipe bundles and drained at a bottom of steam exit chambers of the evaporative condenser; condensate of this steam is drained on the base of the exit chambers of the evaporative condenser and stored in the condensate tank; a condensate tank serves as a condensate reservoir that is pumped by pumps for a turbine cycle; the condensate tank is suspended on a base and receives condensed water from the entire vacuum condensation system; the duct exhaust steam, condensate of the evaporative condenser, steam condensate from the intermediate condenser and a trap condensate of a steam separator; the system has pipes that discard the condensate from the evaporative condenser, an intermediate condenser, the steam separator and the steam duct in the tank; the water of the condensate tank is withdrawn by two pumps of condensate connected by piping; all the condensate is removed through drains in the lower part of the duct, in this area there is a level monitoring point and two more monitoring points are installed in the duct.

10. Vacuum condensation system by using evaporative condenser and air removal system coupled to condensing turbines in thermoelectric plants, according to claim 9, wherein the evaporative condenser comprises a heated air exhauster, steam chambers, a bundle of tubes, the condensate tank, a filter, recirculation pumps, spray nozzles for water, troughs, a grid for mist elimination, baffles, a support and an access platform; the condenser has the exhauster moved by an electric motor that drives the propeller and moves the air forming an air flow in the center of the evaporative condenser, which exhausts the heat away from the equipment.

11. Vacuum condensation system by using evaporative condenser and air removal system coupled to condensing turbines in thermoelectric plants, according to claim 9, wherein the recirculation system that wets tube bundles of the condenser and the incondensable are removed by the ejector, thereby maintaining the vacuum in the system which propagates to the rotors of the vacuum condensation turbines.

12. Vacuum condensation system by using evaporative condenser and air removal system coupled to condensing turbines in thermoelectric plants, according to claim 9, wherein the spray nozzles that receive water from the pump of recirculation stored in a trough are positioned on the condenser base; recirculation is done by pumping water to the nozzles above the tubular bundles; the recirculation pump receives the water from the troughs and goes through a pipe that pass as inside the intermediate and final condenser, from this the water exits and goes to a set of spray nozzles forming a curtain of water over the tubes; this recirculation of water is utilized to cool the interior of the intermediate and final condenser to condense driving steam of the ejector that is together with air and is discarded by the ejectors.

13. Vacuum condensation system by using evaporative condenser and air removal system coupled to condensing turbines in thermoelectric plants, according to claim 9, further comprising filters that prevent debris from getting to spray nozzles clogg the suction of a recirculation pump.

14. Vacuum condensation system by using evaporative condenser and air removal system coupled to condensing turbines in thermoelectric plants, according to claim 9, further comprising an ejector steam system that removes the air.

15. Vacuum condensation system by using evaporative condenser and air removal system coupled to condensing turbines in thermoelectric plants, according to claim 9, further comprising an intermediate condenser and a final condenser.

16. Vacuum condensation system by using evaporative condenser and air removal system coupled to condensing turbines in thermoelectric plants, according to claim 9, wherein the steam separator that separates the steam from the condensed before powering up the ejectors.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0023] FIG. 1a: isometric view of vacuum condensation system.

[0024] FIG. 1b: isometric view of the steam duct that integrates the turbine in the evaporative condenser.

[0025] FIG. 2: top view of the cogeneration energy system using the vacuum condensation system to condensate the exhaust steam.

[0026] FIG. 3: side view of the vacuum condensation system showing the components of the capture of the exhaust steam condensed.

[0027] FIG. 4: side view of the vacuum condensation system showing the components of the water recycling system.

[0028] FIG. 5: isometric view with the cut of the evaporative condenser showing the baffles.

[0029] FIG. 6a: isometric view with a cut of the evaporative condenser showing the input of the steam and the exit of the condensed, as well as an indication of the steam flow (26).

[0030] FIG. 6b: isometric view of the tube representing the condensation that happens in the tubular pipe bundle (41) of the evaporative condenser.

[0031] FIG. 7: top view of the condensed tank system and condensed pumps.

[0032] FIG. 8a: side view of the steam duct representing the level sensors.

[0033] FIG. 8b: front view with a cut of the steam duct representing the level transmitter.

[0034] FIG. 8c: front view with a cut of the steam duct representing the level sensors.

[0035] FIG. 9: detailed view showing the system starting ejectors.

[0036] FIG. 10: detailed view of the air removal system demonstrating the ejectors of first and second stage.

DETAILED DESCRIPTION

[0037] As it can be inferred from the accompanying drawings that are an integral part of this description invention patent it is revealed in this document a VACUUM CONDENSATION SYSTEM BY USING EVAPORATIVE CONDENSER AND AIR REMOVAL SYSTEM COUPLED TO CONDENSING TURBINES IN THERMOELECTRIC PLANTS preferably made of stainless steel, metal alloys and other materials. This condensation system is basically composed of an exhaust steam collector (02), a steam duct (01), an evaporative condenser (03) and ejectors (15, 16, 17) with ejectors condensers (13, 14). The operation of the system for energy cogeneration begins with the burning of bagasse of the sugarcane in boilers that produce high-pressure steam. This steam is injected in the turbine to move the rotors and produce electricity. The exhaust steam that that comes off the turbine is collected by the steam collector and is routed to the evaporative condenser for condensation and the condensate formed is pumped to power the boiler as shown in FIG. 2.

[0038] The steam produced in the high-pressure boilers is sent to the turbines moving the rotors attached to the axle that generates mechanical energy. In the turbine axle there is a generator that converts mechanical energy into electrical energy. Since the rotors are positioned in sequential operation on the turbine from the first (input of high pressure steam) to the last (exit of the steam to the condensing system) the vacuum created by the system follows the flow of the steam, thus ensuring lower pressure in the last rotors. In this last stage the rotors of a condensing turbine are designed to work with low pressure steam. For better description the system causes the pressure inside the turbine to change from positive to negative in the last condensation stage of the turbine. The temperature of condensation at atmospheric pressure is 100 C. while the condensation temperature in a vacuum with 0.11 bar (or smaller) is 48 C.

[0039] The steam duct (01) suspended by supports (22) collects the exhaust steam from the condensing turbine through the steam collector (02) using the second law of thermodynamics: For the steam to produce work, it is necessary to have a differential of temperature and pressure. The exhaust steam already at low pressure is led to the evaporative condenser (03), where happens the transformation of steam into condensed water which is again done with the aid of the recirculating water. The turbine exhaust steam passes through the duct (01) and is distributed through distribution ducts (04) in the steam input chamber (05), distributed in the tubular pipe bundles (41) and drained at the bottom of the steam exit chambers (08) of the evaporative condenser (03).

[0040] The condensate of this steam is drained on the base (24) of the exit chamber (08) of the evaporative condenser (03) and stored in the condensate tank (27). The condensate tank (27) serves as a condensate reservoir that is pumped by pumps (31) for the turbine cycle. The condensate tank (27) is suspended on a base (29) and receives condensed water from the entire vacuum condensation system by the pipes (28). More specifically it receives the condensed water from the duct exhaust steam (01), condensate of the evaporative condenser (03), steam condensate from the intermediate condenser (13) and the trap condensate (67) of the steam separator (47).

[0041] The system has pipes (71, 72, 73, 74) that discards the condensate from the evaporative condenser (03), intermediate condenser (13), a steam separator (47) and a steam duct (01) in the tank (27). These pipes of condensate discharge should be submerged in the tank, that is, it must have a minimum level of water in the condensate tank to keep the pipes immersed and not break the vacuum.

[0042] The water of the condensate tank (27) can be withdrawn by two pumps of condensate (31) connected by piping (30), during the operation a pump is turned on and the other remains as a reserve. The condensate level in the tank is controlled by a level transmitter installed on the bottom of the tank (27) and a control valve in the exit line. When the condensate level reaches the lowest point, the valve closes and when the condensate level begins to reach a higher point, the valve opens. When the level reaches the top edge it triggers the level switch. To help lower the tank level, the condensate pump (31), that was standing by, is turned on, and that status is maintained until the level is lowered. The condensate pumps (31) are sealed with external water, for safety one actuated valve is placed in the water input ensuring that no pump will turn on when the valve is closed. In the water input of the seal of each pump has a manual valve, it should remain open.

[0043] All the steam condensate in the duct (01) should be taken out ensuring that it does not return to the turbine. The condensate is removed through drains (33) in the lower part of the duct (01), in this area there is a level monitoring point and for safety two more monitoring points (34, 35) are installed in the duct (01). The system redundancy with the installation of three level instruments serves to ensure that the operator is informed and that the action be taken.

[0044] The system has a security control that prevents the turbine operation with a high level of condensate in the duct, thereby preventing the arrival of liquid in the turbine rotors. This system is composed by a level transmitter (36) and a level switch which monitors the level in the duct. If it reaches the level of the first key (high attention level), the operator will be notified in order to check the operation of the drainage system in the duct (pumps). If the level continues to rise and reaches the second key (operating emergency level) the operator is alerted that the turbine steam supply will be shut down in X seconds and the whole system will shut to protect the condensate return to the turbine. The system will be stopped until all the condensate is removed from the duct and the drainage system checked.

[0045] The system main component is the evaporative condenser (03), a device that uses thermodynamic principles to accomplish the condensation of turbine exhaust steam and generate vacuum in the rotor in the last stage of the turbine. The main components of the evaporative condenser are exhaust heated air (10), steam chambers (05, 08), bundle of tubes (41), condensate tank (27), filter (44), recirculation pumps (46) spray nozzles (40) of water, troughs (76), grid for mist elimination (92), baffles (06), support (09) and access platform (68).

[0046] This condenser (03) has a constructive and operational improvement. Constructively this equipment was perfected to condense by vacuum the turbine exhaust steam via a tubular bundle system (41) cooled by the joint action of the air current produced by the exhauster (10) and the water spray by the nozzles (40) forming the physical effect of wet bulb temperature. The turbine exhaust steam is led through the steam duct and distributed through the distributor duct in the steam input chamber (05) and distributed in tube bundles (41) of the evaporative condenser (03). On the tube bundle (41) there is a set of nozzles sprays (40) which spray water on the outer surface of the tubes (90) through the water curtain where there is a flow of air moved by the exhauster (10) which cools the water to the wet bulb temperature. The steam in contact with the cooled wall of the tube undergoes condensation, and this condensate moves to the steam exit chambers, at the bottom there is a drain to remove this condensate and forwards it to a reservoir (27) of condensed water. It is worth noting that the turbine exhaust steam condensed inside the tubular pipe bundle circulates only inside the beams and the cooling water responsible for cooling the tubes have no direct contact with the vapor to be condensed. This evaporative condenser is symmetrically equal, it has two tube bundles (41), two spraying systems (40), triangular troughs (91), trough or cooling water reservoir (76) positioned at opposite sides.

[0047] The condenser (03) has an exhauster (10) moved by an electric motor (12) that drives the propeller (18) and moves the air forming an air flow in the center of the evaporative condenser (03), which exhausted the heat away from the equipment. This movement of air along with the water spray on the tubular bundle (41) promotes the condensing effect using the wet bulb temperature. For this exhaust not to drag the water the evaporative condenser has a screen which eliminates the drag of the drops.

[0048] The recirculation system wets the tube bundles (41) of the condenser and the incondensable are removed by the ejector (air), thereby maintaining the vacuum in the system which propagates to the rotors of the vacuum condensation turbines. In this condensing system the ejectors (15, 16, 17) are positioned on top of the evaporative condenser. They remove the air as a way to make exchange of heat more efficient, since the air gases are incondensable.

[0049] The system of spray nozzles (40) (sprays) receives water from the pump (46) of recirculation stored in the trough (76) and drains by pipe (78) positioned on the condenser base (03). This water from the evaporative condenser trough is continuously recirculated to maintain the outer wall of the tubes wet (93). The recirculation is done by pumping the water to the nozzles (40) above the tubular bundles. The recirculation pump receives the water from the troughs (76, 75) goes through the pipe (45) that pass inside the intermediate (13) and final (14) condenser, from this the water exits and goes to the set of spray nozzles (40) forming a curtain of water over the tubes. This recirculation of water is utilized to cool the interior of the intermediate (13) and final (14) condenser to condense the driving steam of the ejector that is together with air and is discarded by the ejectors (15, 16, 17).

[0050] This water sprayed over the hot tubes (93) along with the air movements promotes the evaporation of part of this cooling water which is constantly replenished in accordance with the level of the water troughs (76). This water control is performed by a level transmitter (43) which detects the level of the trough (76) and by the modulation of the replacement water input control valve (42) to maintain the water level according to the desired level. This replacement of water is calculated according to the amount evaporated being 1: 1, that is, for every 75 t/h of steam condensate it is necessary to replace 75 t/h of water. Comparing with conventional condensing systems it is necessary to replace less amount of water.

[0051] To prevent debris from being thrown in the spray nozzles (40) causing clogging it is installed a filter (44) in the suction of the recirculation pump (46). It is recommended to open the valve of the recirculation pump filter (46) at least once a day for a short period of time, to remove the dirt lying inside the filter (44). If is necessary to replace the water of the condenser (03) it should be opened the drain located at the bottom of the trough (76) or by the filter valve (44) of the recirculation pump (46) eliminating all the water.

[0052] Another advantage of this system is the fact that the air removal is performed with ejectors (15, 16, 17) causing an energy saving compared with systems that utilize vacuum pump, since the ejectors operate with high pressure steam and the pumps operate consuming electricity. Intermediate condenser (13) and the Final Condenser (14) are essential for the air removal system because two thrusters working in sequence to achieve the operating vacuum is necessary to place between the ejectors a condenser (13); whose function is to condense the steam which is disposed by the 1St stage ejector (16), and then for the 2.sup.nd ejector (17) to suck only air. The condensed vapor in the intermediate condenser (13) is discarded on the condensate tank (27) and the final condenser (14) is discarded in the troughs (76) of the evaporative condenser (03).

[0053] The ejectors (15, 16, 17) have the function of removing incondensable gases (air) from the system, this is done by high pressure steam passing through the nozzle that causes the decrease of the static pressure, thus dragging out the air from the equipment. The system mentioned in this document consists of one Starting Ejector (15), one 1.sup.st Stage Ejector (16) and a 2.sup.nd Stage Ejector(17) it may or may not have Reserve Ejectors (50, 52). As they are represented in the figures, the ejectors have a steam input, an air input, an air and steam exit and a nozzle that operate to remove the air from the system.

[0054] The 1.sup.st Stage Ejector (16), 2nd Stage (17) and Starting Ejector (15) have different characteristics, as follows: [0055] Starting Ejector (15): It is characterized by a greater flow of air, but it can't reach the operating vacuum, so it is used only at the start of the condenser and then it closes. [0056] 1st Stage Ejector (16): with a smaller air flow, but capable of reaching the operating vacuum when working together with the 2nd stage ejector, the 1.sup.st stage ejector is responsible for removing all the air from the Evaporative Condenser Chamber and discard it in the intermediate condenser. [0057] 2nd Stage Ejector (17): with a smaller air flow, but with the capability of achieving the vacuum operation, it just sucks the air ejected by the 1st Stage Ejector and discards it at the final condenser (atmosphere).

[0058] The system also has a steam separator (47) that separates the steam from the condensed before powering up the ejectors (15, 16, 17). The steam separator (47) is composed of the following items: Steam Separator's body that is used to separate debris that are in the pipeline and in the steam condensate; Steam Entry; Steam Exit for the ejectors; Exit of the condensate for the condensate tank; Drain Valve; Pressure Transmitter shut-off Valve; Pressure Transmitter seal tank; Pressure transmitter is used to monitor the steam pressure in the input line; Condensate exit Lock valve; Y filter used to protect the dirt trap from the trap system.

[0059] The steam power up of the ejectors (15, 16, 17) is directed by the separator (47) and pipes (54) until the ejectors. The steam goes two ways, one way it powers up the Starting Ejectors (15) and the other it powers up the 1.sup.st Stage(16) and 2nd Stage (17) Ejectors.

[0060] As shown in the figures this constructive arrangement of the ejectors (15, 16, 17) has an autonomously input steam system, when triggered to perform vacuum during the start it releases steam for the Start Ejectors (15) 1 Stage (16) and 2nd Stage (17) and when it reaches the starting vacuum (close to operation vacuum) blocks the steam entrance to the Start Ejectors (15).

[0061] Each ejector (15, 16, 17) has a manual valve in the steam input, which is used for system maintenance.

[0062] For system air removed in the beginning of the process it is used the Start Ejectors (15) that has a greater air flow.

[0063] The suction of the 1.sup.st Stage Ejector (16) is connected to the exit steam chambers of the evaporative condenser to remove air from the system and discard in the intermediate condenser (13), the 2.sup.nd Stage Ejector (17) is responsible for removing only the air from the intermediate condenser (13) and discarding in the final condenser (14) and all the air of the final condenser (14) exits to the atmosphere through the silencer (19).

[0064] As shown in the vacuum condensing system the air removal and the pressure of each evaporative condenser (03) is monitored and controlled with the aid of a vacuum meter and an absolute pressure transmitter.

[0065] For all that it was shown this invention patent document refers to a vacuum condensing system that may be designed and manufactured with different sizes and capacities.