US2384587A

US2384587A - System for generating steam

Info

Publication number: US2384587A
Application number: US522557A
Authority: US
Inventors: Badenhausen John Phillips
Original assignee: Individual
Current assignee: Individual
Priority date: 1944-02-16
Filing date: 1944-02-16
Publication date: 1945-09-11
Anticipated expiration: 1962-09-11

Description

Sept. 11, 1945. V .1. P. BADENHAUSEN 2,384,537

SYSTEM FOR GENERATING STEAM Filed Feb. 16, 1944 IN V EN TOR.-

Patented Sept. 11, 1945 UNITED STATES PATENT OFFICE 9 Claims.

This invention relates to systems for enerating steam and more particularly to such systems for generating and delivering steam free from objectionable carry-over of solids content.

In accordance with the present invention provision is made for the continuous generation of steam of high purity free from objectionable s01- ids content.

In accordance with the present invention also, provision is made for segregating and separating the extraneous solid materials in solid and in liquid form so that the same may be readily removed from time to time.

In accordance with the present invention also, provision is made for the continuous operation of high capacity steam generators without the necessity of shutdown for cleaning.

The present invention also contemplates the provision of simple apparatus for providing steam of higher purity than has heretofore been. obtained.

The invention further contemplates apparatus capable of use with existing installations for overcoming troubles heretofore encountered.

Other objects of the invention will be apparent from the annexe specification and claims.

The nature and characteristic features of the invention will be more readily understood from the following description, taken in connection with the accompanying drawing forming part hereof, in which:

Figure 1 is a diagrammatic view of a power plant known to the art which is included for purposes of explanation of the invention; and

Fig. 2 is a diagrammatic view of a preferred embodiment of the present invention.

It will, of course, be understood that the description and drawings herein are illustrated merely, and that various modifications and changes may be made in the structure disclosed Without departing from the spirit of the invention.

Referring more particularly to Fig. 1 of the drawing a typical power plant is illustrated diagrammatically which includes a steam generator ID, a turbine H to which steam is supplied from the steam generator I!) through a steam main I6, a condenser |2 for receiving exhaust from the turbine II, a return line |8 for the condensate, a make-up evaporator |3 heated by steam tapped from the turbine H at the desired stage and delivered through a pipe l1, and a feedwater heater H, the water for make-up being supplied to the make-up evaporator 3 through a pipe I5. In addition to the foregoing there is also shown a 10 superimposed steam 5 of the character employed in many modem or modernized steam power plants.

In the operation of the lower pressure portion of the system including the steam generator It, the turbine H and the condenser 2, without a generator 20 and topping turbine 2| n0 difficulties are encountered with the deposit of solids in the turbine H. In systems employing a superimposed steam generator 20 and a topping turbine 2|, difiiculties have been encountered not only in the superimposed steam generator where the presence or deposition of solid materials has caused unexpected tube failures, but also by reason of the carrying over from the steam generator 20 of certain solids which have deposited at certain locations in the system. No deposit has been noted in the topping turbine 2| but solid materials have deposited in the main turbine usually at a location where the temperature ranges from approximately 585 F. to 600 F. and at a pressure below approximately 275 pounds. Analysis of the deposits taken from the turbine blading indicated that the principal constituents were sodium hydroxide and sodium silicate although other boiler water salts were also found to be present. The solids deposited did not however reflect the same percentage of materials as those found in the boiler water.

Apparently upon the raising of the temperature and pressure of the steam to the high ranges required for the operation of topping turbines, such as the turbine 2|, some dissociation or vaporization of the salts therein occurs and upon subsequent reduction in temperature and pressure these materials are redeposited in the system in solid form. The velocity of flow of the steam particularly in the turbine I does not seem to be adequate for preventing such deposition.

Numerous instances have been recorded in which the output capacity of turbines has been continuously decreased by the deposit of solids, and to an extent of more than one-quarter in one months time. In other instances turbines have been out of service for considerable periods of time because of the solids deposited therein.

Various attempts have heretofore been made to remedy the situation. Washing of the steam with feedwater has been tried with only indifierent success. It has also been suggested that the feedwater treatment should be changed, but such changes have not produced any very marked improvement.

In a steam generating system such as those employed in central station service where the quantitles of steam are large and of the order of a million pounds of steam in from one to ten hours, and where the make-up is of the order of 2 or 3% the continuous introduction of even a relatively small quantity of solid material has a cumulative effect which may quickly become troublesome.

Referring now more particularly to Fig. 2, the power plant there shown diagrammatically, includes a steam generator I and main steam turbine II and a condenser I2 with provisions such as the line l8 for returning the condensate for continuous generation of steam. The superimposed steam generator 20 supplies steam to the topping turbine 2| which discharges to the main steam turbine ll. While two separate turbines are illustrated at 2| and II, it will, of course, be understood that the same could be readily embodied in a single casing with interstage supply of the steam from the steam generator In.

In accordance with the present invention and for the purpose of supplying water of high purity for make-up, as well as for the initial supplying of water of high purity for operation of the system, a precipitator 30 is provided which is adapted to generate steam, preferably at a higher temperature and pressur than that of the superimposed steam generator 20, for the purpose of retaining in the precipitator 30, in solid and in liquid form, certain of the materials heretofore carried over in the steam. The precipitator 30 is preferably a steam generator capable of retaining such materials and capable of being readily cleaned and for this purpose a precipitator such as that shown in my priorapplication for Letters Patent filed December 22, 1943, Serial No. 515,245, or in my prior application for Letters Patent for Steam generating systems filed February 16, 1944, Serial No. 522,556, may be employed.

The precipitator 30 is of much smaller size than either of the steam generators 20 and I0 and has a capacity such to provide the requisite make-up for the system. The precipitator is preferably connected by a steam line 3| to a turbine 32 for the expansion of the steam to a predetermined level of pressure and temperature and for the extraction of the energy during the expansion. The turbine 32 is connected to a desuperheater or cooling unit 33 for the purpose of reducing its temperature, if required, to the desired range. The unit 33 is connected to a collecting chamber or tower 3'4 such for example as that shown in my application for Letters Patent for Steam generating systems, filed February 16, 1944, Serial No. 522,556, although any other suitable collector for the solids content of the steam may be employed. The tower 34 is connected to discharge steam to a heat exchanger or indirectly heated steam generator 35 such for exampleas that shown in my prior Letters Patent for Steam generators, No. 2,336,832, issued December" 14,-1943. The pipe 35 is provided for supplying the raw water which, after heating or in the form of steam, is supplied through the pipe '31 to the steam generator 30. The condensed steam from the heat exchanger 35 discharges through a pipe 38 and is supplied as makeup to the power plant through a supply pipe 39. If desiredfa portion of the condensate from the pipe 38 may be employed in the desuperheater or cooling unit 33, the pipe 40 being provided for delivery thereof,

The operation of the system in accordance with the present invention will now be pointed out, reference being had particularly to Fig. 2.

The steam generator 10 may be operated to deliver steam at a temperature of the order of 750 F. and at a pressure of the order of 275 pounds. The steam generator 20 may be operated to supply steam at a pressure of the order of 1,250 pounds and at a temperature of the order of 920 F. and water is supplied to the steam generator 10 and to the steam generator 20 at a temperature of the order of 400 F. The turbines 2i and II are operated by the steam supplied thereto from the steam generators 20 and i0 and the condensate from the condenser 12 is returned through the line l8.

For the purpose of supplying make-up free from solids content the precipitator 30 is preferably operated for the generation of steam at a pressure several hundred pounds higher than that of the steam supplied by the steam generator functioning at the highest pressure required by the turbine 2i. The precipitator 30 may be operated at a pressure of the order of 1,800 pounds and at a temperature of the order of 920 F. The precipitator 30 is supplied with water as hereinafter set forth in accordance with the make-up requirements through the line 31 and the temperature of the water thus supplied may be of the order of 400 F.

The raising of the temperature of the fluid within the precipitator 30 in the range from approximately 400 F. to approximately 920 F., with generation of steam at a pressure of the order of 1,800 pounds, will cause certain of the contaminating solids to be segregated so that they may be retained in the precipitator 30 in the form of solid incrustations on the tube walls and also dissolved in the water. By this character of operation the solids are not delivered in appreciable quantity beyond the precipitator 30. The separated and segregated solids deposited in solid form as tube incrustations may be removed by cleaning the tube surfaces of the precipitator 30 and the solids in dissolved form may be removed by discharging the water containing the same from the precipitator 30. Certain of the solids at high temperature ranges, as heretofore indicated, are vaporized or sublimed.

The steam from the precipitator 30 passes to and through the turbine 32 which for a fiow of steam of the order of 30,000 pounds per hour will be capable of generating approximately 1,000 kw. The pressure is reduced in passing through the turbine 32 to approximately 275 pounds and the temperature is reduced to approximately 599 F. The temperature is further reduced, but preferably not below about 585 F., at the desuperheater or cooling unit 33 by water sprayed therein from the pipe 40. This reduction will be effective for throwing down the solids content which may have carried over from the precipitator 30. The solids content will be in the form of precipitates or incrustations or other solid form. The reduction of temperature and pressure in the turbine to 599 F. and 275 pounds will bring the steam approximately to the range where the solids may be separated and collected. The furtheir reduction of temperature and pressure in the desuperheater or cooling unit 33 will be effective for this purpose and the solids thus separated are collected in the tower 34 in the form of precipitates or incrustations on the surfaces therein. The collected material may be removed from time to time as desired.

The steam freed of the remainder of the solids content is then preferably utilized for heating the feedwater supplied to the precipitator 30 through the

pipes

36 and 31 to a temperature of the order of 400 F. The condensate is available in the

lines

38 and 39 for supplying Water, free from solids content, to the power plant through the line 39.

The operation of the precipitator 30 at a higher temperature and pressure range than that of the superimposed steam generator or highest pressure steam generator of the power plant permits of the separation of solid materials prior to the delivery of motive fluid for makeup to the main power plant and such solids as are carried in vapor form with the steam are collected and segregated at the tower 34 in an efiective manner. At the same, time the energy available in connection with the preparation of the makeup of high purity is effectively utilized.

I claim:

1. Apparatus for supplying make-up to a closed motive fluid circuit power plant having a high capacity main steam generator therein including a second steam generator for generating steam at a higher pressure than said main steam generator, expanding means including a prime mover connected to said second steam generator, means for reducing the pressure and temperature of the steam from said prime mover, and a chamber for receiving steam from said reducing means and for collecting solid materials carried by said steam, and fluid delivery connections from said chamber to said main steam generator.

2. Apparatus for supplying make-up to a closed motive fluid circuit power plant having a high capacity main steam generator therein including a second steam generator for generating steam at a higher pressure than said main steam generator and for retaining solid materials, expanding and power extracting means connected to said second steam generator, pressure and temperature reducing means connected to said expanding means, and means connected to said reducing means for collecting solid materials carried by said steam, and fluid delivery connections from said collecting means to said main steam generator for the delivery thereto of fluid free from solid materials.

3. Apparatus for supplying make-up to a closed motive fluid circuit power plant having a high capacity main steam generator therein including a second steam generator for generating steam at a higher pressure than said main steam generator and for retaining solid materials, means connected to said second steam generator for expanding the steam from said second steam generator and for reducing the temperature and pressure of the steam, means for receiving steam from said expanding and reducing means and for collecting solid materials carried by said steam, means for condensing the steam freed of the solid collected material and for feeding the same to said main steam generator.

4. Apparatus for supplying make-up to a closed circuit steam system having a high capacity main steam generator therein including an additional steam generator for generating steam at a higher pressure than said main steam generator and for retaining solid materials, means for reducing the pressure and temperature of the steam from said additional steam generator and for extracting power therefrom during said reduction, means for collecting solid materials thrown down by said reduction, a heat exchanger for condensing said steam for said make-up and for heating the fluid supplied to said additional steam generator with residual heat from said steam, and fluid delivery connections from said heat exchanger to said main steam generator for the delivery thereto of condensate freed of solid materials.

5. Apparatus for supplying make-up to a closed circuit steam system having a high capacity main steam generator therein including an additional steam generator for generating steam at a higher pressure than said main steam generator and for retaining solid materials, means for reducing the pressure and temperature of the steam from said additional steam generator and for extracting power therefrom during said reduction, means for collecting solid materials thrown down by said reduction, a heat exchanger for heating the fluid supplied to said additional steam generator with residual heat from said steam, and fluid delivery connections to said mainsteam generator for the delivery thereto of make-up free of solid materials.

6. Apparatus for supplying make-up to a closed circuit steam system having a high capacity main steam generator therein including an additional steam generator for generating steam at a higher pressure than said main steam generator and for retaining solid materials, means for reducing the pressure and temperature of the steam from said steam generator and for extracting power therefrom during said reduction, means for collecting solid materials thrown down by said reduction, a heat exchanger for condensing the steam from said collecting means for said make-up, and fluid connections from said heat exchanger for the delivery of said make-up.

7. Apparatus for supplying condensate of high purity including a steam generator for collecting and retaining solid materials in solid and liquid form, means including a prime mover for reducing the pressure and temperature of the steam from said steam generator, means for collecting solid materials thrown down by said reduction, and means including a heat exchanger for condensing the fluid from said collecting means.

8. Apparatus for supplying condensate of high purity including a steam generator for collecting and retaining solid materials in solid and liquid form, means for reducing the pressure and temperature of the steam from said steam generator, means for collecting solid materials thrown down by said reduction, and means including a heat exchanger for condensing the fluid from said collecting means.

9. Apparatus for supplying condensed steam of high purity including a steam generator, means including a prime mover for reducing the pressure and temperature of the steam from said steam generator, means for receiving the steam from said reducing means and for collecting solid materials thrown down by said reduction, and means for further reducing the temperature of the fluid from said receiving and collecting means.

JOHN PHILLIPS BADENHAUSEN.