US2626005A

US2626005A - Method and apparatus for removal of ammonia in boiler feedwater systems

Info

Publication number: US2626005A
Application number: US69926A
Authority: US
Inventors: Joseph F Sebald
Original assignee: Worthington Corp
Current assignee: Worthington Corp
Priority date: 1949-01-08
Filing date: 1949-01-08
Publication date: 1953-01-20
Anticipated expiration: 1970-01-20

Description

Jan, 20, 1953 SEBALD METHOD AND APPARATUS FOR REMOVAL OF AMMONIA IN BOILER FEEDWATER SYSTEMS Filed Jan. 8, 1949 TRAP CONDENSATE K VENT To BQILER$\ 20 8 I-KSTEAM SUPPLY 1 l2 1 2 DE SPF'IE CONDENSATE 9 CONDENSED EVARVAPOR & GA R P EZTECTOR CONDENSATE l0 4. DEGASXFIED MAKE UP &

ETECTOR CONDENSATE CONDENSER EvAP. VAPOR (Mm: UP)

EVAPORATOR Q ETRAP CONDENSATE verg'rj To BOILERS gQ-STEAM SUPPLY Ll v ;0NDENSATE CONDENSED EVAP. VAPOR & DEG'ASF ER PUMP I ETECTOR CONDENSATE DEG-AS|F\ED MAKE UP & EII'ECTOR CONDENSATE 3| Ia. EVAP.

CONDENSER EVAP. con. BRAINS EVARAPQR (MAKE up) EVAPORATQR CONDENSATE fl6a TRAP CONDENSATE 'g TO BOILERS awn-STEAM SUPPLY l J 33 DEG'ASIFIER couozusao EVAP. VA POR T; P '0 & EU'ECTQR CONDENSATE d. DEG-ASIFIED MAKE UP & :5 EJECTOR CONDENSATE F165 Hex TRAP

JOSEPH-F. SEBALD IN VEN TOR.

Patented Jan. 20, 1953 METHOD AND APPARATUS FOR REMOVAL OF AMMONIA IN BOILER FEEDWATER SYSTEMS Joseph F. Sebald, Bloomfield, N. J., assignor to Worthington Corporation, Harrison, N. J., a corporation of Delaware Application January 8, 1949, Serial No. 69,926

This invention relates to boiler feedwater systems of power plants and the primary object of the invention is to provide a method and apparatus for removing ammonia from boiler feedwater.

Ammonia which is present in some degree in the water utilized in boiler systems is detrimental and causes corrosion of copper base alloy metals much of which is used in the apparatus of a boiler feedwater system of a power plant, and the present invention provides means for removal of substantially all of the ammonia from such water by degasification and scrubbing of the water, particularly the water from the evaporator make-up and the condensate from the ejectors employed for withdrawing the'non-condensible gases from the system.

With these and other objects in view, as may appearfrom the accompanying specification, the invention consists of various features of construc tion and combination of parts, which will be first described in connection with the accompanying drawings, showing a method and apparatus for removal of ammonia and other gases in boiler feedwater systems of a preferred form embodying the invention, 'and the features forming the invention will be specifically pointed out in the claims.

In'the drawings:

Figure 1 of the drawings shows a diagrammatic view of one form of the ammonia and other gases removing method and apparatus.

Figure 2 is a diagrammatic view of another form of the apparatus and method of removing ammonia and other gases from boiler feedwater difiering slightly from the system illustrated in Figure 1.

Figure 3 is a diagrammatic view of still another form of the ammonia and other'gases removing system wherein an independent condenser is employed for condensing the vapor from the makeup water evaporator instead of utilizing either the inter or after condenser of the ejector for such wear.

Referring more particularly to the system shown in Figure 1 of the drawings, I indicates the surface condenser of a boiler feed system which may be of any approved type of surface condenser employed for condensing the exhaust steam from the prime mover such as a turbine orother engine (not shown). As is well known in boiler feed systems, the condensate from the condenser I is returned to the boiler for conversion into steam or vapor for reuse. However, noncondensible gases such as oxygen or air leak into 17 Claims. (Cl. 183-25) the system and to prevent the corrosion and erosion of the various pieces of apparatus in a boiler feed system such non-condensibles are removed and in the diagram shown in Figure 1 of the drawings the non-condensibles are withdrawn from the condenser I by a combination mult'i-jet ejector and condenser structure 2 of any approved construction. The ejector 2 operates in the usual manner of ejector, withdrawing the non-condensible gases from the-condenser I with steam as a motive power. The steam utilized in the ejectors is condensed in an inter-condenser 3 for the first stage of the ejector and an after condenser I for the last or 'final stage. Any noncondensibles released in the inter and after condensers 3 and 4 by the condensation of the steam or condensible vapors is vented through a suitable vent 5. In the system shown in Figure 1 of the drawings the condensate from the condenser is pumped by a condensate pump 6 through the coils or tubes 1' of the inter and after condensers 3' and 4 and from thence to the boilers through a suitable line 8. All of the above is standard construction and arrangement of apparatus in boiler feed systems. In the present invention the condensate from the inter and after condensers 3' and '4 pass into a suitable condensate or hot well-9 from which it is picked up by a transfer pump I0 and delivered to adegasifier I I.

The degasifier II maybe of any approved type preferably a direct contact degasifier or feedwater heater such as --those disclosed in Patents 2,308,719 or 2,308,721, although any approved type of direct contact degasifier -may be employed which will provide substantially complete degasification of the, condensate delivered thereto by the pump I0 and at the same time provide a scrubbing action of the condensate by steam. Steam is delivered to the degasifier II from any suitable source of steam supply as indicated at I2 and the degasified liquid condensate passes from the storage space at the bottom of the degasifier II through a suitable trap I3 back into the condenser I through a, suitable pipe or conduit I4, Thefeedwater or condensate from the degasifier II while being shown returned to the system through the condenser I may be returned into the system at any suitable point without departing from the spirit of the invention.

It is necessary to supply make-up water to the system to compensate for water lost during circulation through the system and such make-up water is delivered from any suitable source of supply (not shown) through suitable conduit means I5 to an evaporator I6 in which the makeup water is evaporated by steam from any suitable source (not shown) which is delivered to a suitable steam coil I'l within the evaporator and passes from the coil I! through a suitable conduit IB into the condenser I where it is condensed with the exhaust steam or the system. The vapor from the evaporator I6, that is, the evaporated make-up water delivered thereto is so passed through a suitable conduit I9 into the inter condenser 3 of the evaporator structure 2 where it is condensed and passes with the ejector. condensate into the condensate or hot well 9 from which it together with the evaporator condensate is delivered by the transfer pump II) to the degasifier I I and it is consequently returned into the system from the degasifier II with the degasified ejector condensate.

The ammonia and any other vapors released in the degasifier II are vented therefrom to waste or to atmosphere through a suitable vent 20 so that the degasified make-up water and ejector condensate are returned to the boiler feed system practically free of ammonia.

In the modified system shown in Figure 2 of the drawings, the same apparatus as shown in Figure 1 is employed such as, the condenser I, condensate pump' 6, ejector structure 2', inter condenser 3, after condenser l', hot well 9, transfer pump. I, degasifier I I, and evaporator I6.

Thesystem shown in. Figure 2 differs from the systemshown in Figure 1 of the drawings in that the. evaporated make-up water is delivered from the evaporator I6 tothe after condenser 4,, instead of to the inter condenser 3' of the ejector structure. The point to which the vaporized make-up water is delivered, that is whether it is delivered to the inter condenser or the after condenser of the ejector structure depends upon the pressures in the system, some systems making it practical to deliver the evaporated make-upwater to the inter condenser while the pressures in other systems will make it practical to deliver the evaporated make-up water to the after condenser of the ejector.

The system shown inFigure 3.0f the drawings includes the condenser Ia, condensate pump 6a which delivers the condensate from the condenser through the tubes or coils Ia of. the ejector structure M for condensing th steam utilized by the ejector structure 2a. for withdrawing the noncondensable gases and non-condensed vapor from the condenser la. In the structure shown in Figure 3 the condensate from the condenser Ia, after passing through the tubes or coils Ta, of the inter condenser 3a and after condenser 4a ofthe ejector structure 2ais passed through the tubes of a secondary surface type condenser30 and fromthence to the .boilers through the conduit 8a. in the system shown in Figure 3 the evaporated make-up water passes from the evaporator IGa through a, suitable conduit 3I into the secondary condenser 35 Where it is condensed. The condensate from the secondary condenseri30 passes through a suitable conduit 32. into the hot well 911 where it mixes with the condensate from the inner condensate 3a. and the after condenser' ia. The mixedcondensate is taken from the .hot well 9a by the transfer pump. Illa and. delivered to the degasifier Ila, which may be the same construction as the degasifiers II and II where the condensate is degasified and thoroughlyscrubbed by hot steam andthe ammonia vapor and any noncondensable vapors released in the degasifier Ila are vented towaste through the-vent 20a. The

degasified and scrubbed ejector condensate and condensed make-up water are delivered back into the boiler feed system through the conduit I la either into the condenser id or any other suitable point in the system. The steam utilized in the coil I'Ia ofthe evaporator I60, is shown as delivered to the condenser m but in practice, this steam may be delivered to the condenser Ia as shown to the secondary condenser 33 or to the degasifier I la if it is so desired without departing from thespirit of the present invention.

In all three forms of the systems shown, a vent condenser 33 is indicated in the degasifiers and the tubes of such vent condenser are connected .to the conduit which delivers the condensate from the condensate pump of the main con- -denser to the boilers so that a part of the condensate will flow through the vent condensers 33 for condensing any condensible vapor which passes thereto from the 'degasifier. The use and theconstruction of such vent condensers with degasifiers or deaerators'is Well-known in the art and such vent condensers are shown in'the two 'abovementioned patents disclosing suitable degasifiers for use in the systems just disclosed. Various" traps are installed in the systems, as shown in the 'drawingsfor the usual purpose of such traps, that is, to prevent the back flow of the various vapors and condensates flowing through the system.

Theterm non-condensible is employed in the claims to designate all gases, such as carbon dioxide, sulphur dioxide, oxygen, nitrogen, and anyof the many other gases which may be present, and which under the temperature and pressure conditions that are found in power plant operation, will not condense.

It will be understood that the invention is not to be limited to the specific construction or arrangement of parts shown, but that they may be' widely' modified within" the invention defined by the'claims.

What is claimed is: 1. The method of removal of ammonia from a boiler'feed system ofa power plant wherein condensate is delivered from a main condenser to a boiler which comprises withdrawing a mixture of non-condensed vapor and non-condensible gas fromthe main condenser of a boiler feed system; condensing the vaporand thereby releasing" the non condensible gas of the mixture to waste, supplying'evaporated make-up waterlto the boiler feedsystem at'a-point in advance of delivery-of"the'condensate" to the boiler, mixing the vaporofth'e' evaporatedmake-up water with the non-condensed vapor and non-condensible mixture withdrawnfrom the main condenser. of the'system,condensing the'non-condensed vapors of 'themixtureand make-up water, releasing the non-condensibles to waste, heating and scrubbing the condensed vapor'with' steam and flashvapor ofthe-withdrawn mixture and theva porizedmake-up-water.

3. The method of removal of ammonia from boiler feed systems of power plants as claimed in claim 1 wherein the condensate is passed from the flashing and condensing operation to the main condenser of the boiler feed system.

4. The method of removal ofammonia from a boiler feed system of a power plant wherein condensate is delivered from a main condenser to a boiler which comprises withdrawing a mix-.

ture of non-condensed vapor and non-condensi-J ble gas from a main condenser of a boiler feed system, condensing the vapor and thereby releasing the non-.-condensible gasof the mixture to waste, supplying evaporated make-up water to the boiler feed system at a point in advance of delivery of condensate to the boiler, condensing the non-condensed vapors of the evaporated make-up water, mixing the condensed make-up water with the condensed vapor of the mixture Withdrawn from the main condenser, heating and scrubbing the mixed vapors with steam, flashing and condensing the heated scrubbed vapor to release the ammonia content of the vapor, venting the released ammonia to waste and delivering the relatively ammonia-free condensate to the boiler feed system at a point in the system in advance of delivery of condensate to the boiler.

5. The method of removal of ammonia from boiler feed systems of power plants as claimed in claim 4 wherein the condensate from the main condenser is employed as a cooling medium to effect condensation of the vapor of the vaporized make-up water. v .6. Means for removing ammonia from boiler feedwater in a boiler feed system of a power plant including in combination, a main condenser, an ejector for withdrawing non-condensed vapor and non-condensible gases from the main condenser, a secondary condenser for condensing the vapor passed through the ejector and releasing the non-condensibles to Waste, an evaporator for evaporating makeup water sup-. plied thereto, means for delivering vapor from said evaporator to said secondary condenser for mixture with the vapor passed through the ejector and condensed therewith, a degasifier, a transfer pump for delivering the condensate from the secondary condenser to said degasifier, and means for delivering condensate from the degasifier to the main condenser.

'7. Means for removing ammonia from boiler feedwater in a boiler feed system of a power plant including in combination, a main condenser, means for delivering condensate from the main condenser to a boiler, an ejector for Withdrawing non-condensed vapor and non-condensible gases from the main condenser, a secondary condenser for condensing the vapor passed through the ejector and releasing the noncondensibles to waste, an evaporator for evaporating makeup water, means for delivering vapor from said evaporator to said secondary condenser for mixture with the vapor passed through the ejector and condensed therewith, a degasifier, a transfer pump for delivering the condensate from the secondary condenser to said degasifier, means for delivering condensate from the degasifier into the boiler feed system at a point therein in advance of said means for delivering condensate from the main condenser to a boiler, and means for delivering condensate from said main condenser to said secondary condenser for serving as a cooling medium in the secondary condenser.

8. Means for removing ammonia from boiler feedwater in a boiler feed system including in combination, a main condenser, means fordelivering condensate from the main condenser to a boiler, an ejector for withdrawing'non-c'ondensed vapor and non-condensibles from the main condenser, an inter and after condenser for condensing vapors passed through said ejector and releasing the non-condensibles to waste,'an evaporator for evaporating makeup water, means for delivering vapor from said evaporator to said inter condenser for mixture with the condensa tion from said inter condenser, a degasifie'r, a transfer pump for delivering condensate from the inter and after condensers to said degasifier, and means for delivering condensate'from the degasifier into the main boiler feed system at a point in advance of said means for delivering condensate from said main condenser to said boiler. I

9. Means for removing ammonia from boiler feedwater in a boiler feed. system including in combination, a main condenser, means for delivering condensate from the main condenser -'to a boiler, an ejector for withdrawingnon-condensedvapor and non-condensibles from the main condenser, an inter and after condenser for con densing vapors passed through said ejector and releasing the non-condensibles to waste, an evaporator for evaporating makeup water, means for delivering vapor from said evaporator to said after condenser for mixture with the condensation from said after condenser, a degasifier, a transfer pump for delivering condensate from the inter and after condensers to said degasifier, and means for delivering condensate from the degasifier into the main boiler feed system at a point in advance of said means for delivering condensate from said main condenser to said boiler.

10. The method of removal of ammonia from a boiler feed system of a power plant wherein condensate is delivered from'a main condenser to a boiler which comprises withdrawing a mixture of non-condensed vapor and non-condensible gas from the main condenser of aboiler feed system, condensing the vapor and thereby releasing the non-condensible gas of the mixture to waste, supplying makeup Water to the boiler feed system at a point in advance of delivery of condensate to the boiler, evaporating the makeup water, condensing the condensibles of the makeup water, releasing the non-condensibles from the makeup water to waste, heating and scrubbing the condensed vapor with steam and flashing and condensing the heated scrubbed vapor to release the ammonia content of the vapor, venting the released ammonia to waste and delivering the relatively ammonia-free condensate to the boiler feed system at a point in the system in advance of delivery of condensate to the boiler.

11. The method of removal of ammonia from boiler feed systems of power plants as claimed in claim 10 wherein condensate from the main condenser of the boiler feed system is employed as a cooling medium to effect condensation of the vaporized makeup water.

12. The method of removal of ammonia from boiler feed systems of power plants as claimed in claim 10 wherein a part of the condensate from the main condenser is passed in non-contacting heat exchange relationship with the condensed makeup water.

13. Means for removing ammonia from boiler feed water in a boiler feed system of a power plant including in combination, i a Z'main ;oondenser, means for delivering. condensate .2 from thezmain' condenser. to :a'boil'er, .an. ejector'r-fo'r withdrawing "vapor land-:non-cohdensible gases from the mainv condenser, asecondary-condenser, an evaporator for evaporating makeup water, means for deliveringmakeup water tosaidevaporator, means for delivering vaporfrom said evaporator to said secondary condenser, a degasifier, a transfer pump for delivering thev condensate from the secondary condenser. to .said .degasifier, and means for delivering condensate from the degasifier to the boiler feedzsystem at a point in advance of said means for delivering condensate from said main condenser to a boiler.

14. Means for removing ammonia from boiler feed'water in a boiler feed system of a power plant including in combination-a main 'condenser, means for delivering condensate from said main condenser to a boiler, an ejector for Withdrawing vapor and non-condensiblegases from the main condenser, a secondarycond'enser, an evaporator for evaporating makeup water, means for delivering makeup water to said evaporator, means for delivering evaporating steam to said evaporator, means for delivering evapo rating steam from said evaporator to said main condenser, means for delivering evaporated makeup water from said evaporator to said secondary condenser, a 'degasifier, a transfer pump for delivering the condensate from. the secondary condenser to said degasifier, and means for delivering condensate from the degasifier into the boiler feed system at a point in advance of said means for delivering condensate from said .main condenser to a boiler.

15. Means for removing ammonia from boiler feed water in a boiler feed system of a power plant including in combination, a main condenser, an eiector' for withdrawing-vapor and non-condensible gases from the main condenser, a secondary condenser, an evaporator for evaporating makeup water, means for delivering makeup water to said evaporator, means for delivering evaporating steam to said evaporator, means for delivering evaporating steam from said evaporator to said maincondenser, means for delivering evaporated makeup water from said evaporator to said secondary condenser, a degasifier, a transfer pump for deliveringtthe con densate from the secondary condenser to said degasifier, and means for delivering degasified condensate from said degasifier to said main condenser.

16. The method of removal of ammonia from'a boiler feed system of a power plant whereincondensate is delivered from a main condenser to a" bO iIEIIWhiCh" comprises withdrawing azmixture of rnonecondensed vapor and non-condens'ible gas from theimain condensersoffia boiler'feed: system, condensinglithe' vaporLandither'eby releasing the non-condensibles of the mixture to waste, :supplyingmake-up water to theboiler feed system at apointin advanceof delivery of: condensate to the boiler, passing the make-up water in noncontacting heat exchange relationship with steam to evaporateithe"make-upwater, passing the steam usedto evaporate the make-upwater to the main condenser,. condensingithe condensibles of the make-up water, releasing the non=condensibles' from the makeeup water to Waste, "heating. and scrubbing the: condensed make-up water vapor with steam and flashing and condensing the'heated scrubbed vapor to.'release the ammonia'content of the water, venting the'released ammonia to waste and delivering the relatively ammonia-free condensate to the boiler feed=system at a point in advance of delivery of the condensate to the boiler.

' 17. 'Means for removing ammonia from boiler feed-water in a boiler feed system. ofa power plant including in combination, a main .condenser, means for delivering condensate'from the main condenser to 'a boiler, an ejector for withdrawing non-condensed vapor and non-condensible gases from" the main condenser, a secondary condenser for condensing the vapor passed through the ejector and releasing the non-condensibles to waste, an evaporator for evaporating make-up water, means for delivering vapor from said evaporator to said secondaryconderiser for mixture with the vapor passed through the ejector and condensed therewith-a dega'sifiena transfer pump for delivering the condensate from the secondary condenser to said 'degasifier, means for delivering condensate from the degasifier into the boiler feed system at a point therein in advance of'said meansfordelivering condensate from the main condenser to. a boiler, means'for delivering steam to said evaporator for evaporating make-up water therein, and means for delivering condensed rheating :steam from said evaporator to said main condenser.

' JOSEPH SEBALD.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name, Date 1,408,574 Fothergill et-al 'Mar. 7, 1922 v2,308,721 Sebald Jan. 19, 1943 2,452,716 Bergquist Nov. 2, I948