Shell-and-tube steam generator with economizer

Claim 3

The method of operating a vapor generator as recited in claim 1 wherein proportionately greater amounts of vaporizable liquid are preheated by heat transfer from said heating fluid as the inlet temperature of the liquid is increased.

Claim 4

The method of operating a vapor generator as recited in claim 2 in which the amount of vaporizable liquid passed in heat exchange relation with said vapor is decreased as the amount of vaporizable liquid passed in heat exchange relation with said heating fluid is increased.

Claim 5

The method of operating a vapor generator as recited in claim 1 wherein all of the vaporizable liquid is preheated by heat transfer from said vapor at liquid inlet temperatures of up to about 300* F., and all of said vaporizable liquid is preheated by heat transfer from said heating fluid at liquid temperatures of about 400* F. or higher.

Claim 8

The method of operating a vapor generator as recited in claim 5 wherein proportionately greater amounts of vaporizable liquid are preheated by transfer from said heating fluid as the inlet temperature of the liquid is increased.

Claim 9

The method of operating a vapor generator as recited in claim 6 in which the amount of vaporizable liquid passed in heat exchange relation with said vapor is decreased as the amount of vaporizable liquid passed in heat exchange relation with said heating fluid is increased.

Claim 10

The method of operating a vapor generator as recited in claim 5 wherein all of the vaporizable liquid is preheated by heat transfer from said vapor at liquid inlet temperatures of up to about 300* F., and all of said vaporizable liquid is preheated by heat transfer from said heating fluid at liquid inlet temperatures of about 440* F., or higher.

Claim 11

The method of operating a vapor generator as recited in claim 5 further including the step of superheating that part of the vapor from the evaporator portion that does not preheat the vaporizable liquid.

Claim 12

A vapor generator comprising: a. a vertically elongated pressure vessel; b. axially spaced tube sheets dividing the vessel into heating fluid inlet and outlet chamber and a vapor-generating chamber therebetween; c. a bundle of tubes extending through said vapor-generating chamber and having their ends communicating with said heating fluid inlet and outlet chambers for circulation of heating fluid through said tubes; d. means within said vapor-generating chamber defining an evaporator section and a preheat section; e. baffle means surrounding said tube bundle in concentrically spaced relation from the wall of said vessel to form an annular passage therebetween; said flow passage being in fluid communication with said evaporator section at the lower end thereof; f. means for admitting a portion of the vapor generated in said evaporator section to said annular flow passage; g. means for supplying vaporizable liquid to said vapor generator including: i. first supply for passing said liquid to said annular flow passage into heat exchange relation with the vapor present therein; and ii. second supply means for passing said liquid directly to said preheat section.

Claim 13

A vapor generator comprising: a. a vertically elongated pressure vessel; b. axially spaced tube sheets dividing the vessel into heating fluid inlet and outlet chamber and a vapor-generating chamber therebetween; c. a bundle of tubes extending through said vapor-generating chamber and having their ends communicating with said heating fluid inlet and outlet chambers for circulation of heating fluid through said tubes; d. means within said vapor-generating chamber defining an evaporator section and a preheat section; e. baffle means surrounding said tube bundle in concentrically spaced relation from the wall of said vessel to form an annular passage therebetween; said flow passage being in fluid communication with said evaporator section at the lower end thereof; f. means for admitting a portion of the vapor generated in said evaporator section to said annular flow passage; g. means for supplying vaporizable liquid to said vapor generator including: i. first supply for passing said liquid to said annular flow passage into heat exchange relation with the vapor present therein; and ii. second supply means for passing said liquid directly to said preheat section.

Claim 14

A vapor generator as recited in claim 10 wherein said baffle means is in open fluid communication with said evaporator section at the top and bottom ends thereof and the opening at the top of the said baffle means is effective to admit vapor from said evaporator section to said flow passage while that at the bottom admits heated liquid to said evaporator section.

Claim 15

A vapor generator as recited in claim 11 wherein said liquid is heated to substantially its saturation temperature in said flow passage.

Claim 16

A vapor generator as recited in claim 10 including control means for regulating the supply of vaporizable liquid through said first and second supply means in response to changes in the temperature of the liquid being passed.

Claim 17

A vapor generator as recited in claim 10 including control means for regulating the supply of vaporizable liquid through said first and second supply means in response to changes in load on said vapor generator. amounts

Claim 18

A vapor generator as recited in claim 14 wherein said control means includes means for passing all of the liquid supplied to said vapor generator through said first supply means during low load operation of said vapor generator, means for passing all of the liquid supplied to said vapor generator through said first supply means during high load operation of said vapor generator, and means for passing liquid through both of said supply means in controlled amounts during intermediate load operation of said vapor generator.

Claim 19

A vaPor generator as recited in claim 11 wherein said preheat section includes means for directing the flowing liquid in crossflow relation to the tubes extending therethrough.

Claim 20

A vapor generator as recited in claim 16 including means defining a superheat section in said vapor-generating chamber disposed above said evaporator section and said means including means for directing the flowing fluid in crossflow relation to the tubes extending therethrough.