US 4,732,590 AGranted

Flash economizer

OwnerJohn A. McNeilinventor

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Abstract

A flash economizer employing an enclosed upright container has upper, intermediate and lower chambers for flashing pressurized blowdown effluent in the nature of moisture-contaminated steam. It is constructed to initially separate and remove pure steam in its upper so-called flashing chamber and to thereafter maximize, principally in the intermediate chamber, an indirect transfer of heat from the remaining heat-containing condensate or water to a clean effluent, such as make-up water. An upwardly spiraled tubing array positioned about and along the intermediate chamber receives the clean effluent and advances it in an upwardly spiraled counterclockwise path therealong, while the heat-containing condensate is directed in a downflow, counter or clockwise-spiraled path along the tubing array. The tubing array is carried by an enclosing support structure that defines a spiral downflow path for the heated condensate therealong and therabout. Enlarged inlet and outlet tubing members extend into and along the lower and into the intermediate chamber in a spaced relation with respect to each other, with the outlet or return tubing member extending along an inner periphery of the tubing array and along a substantially central supporting structure about which the array extends within the intermediate chamber. Downflow of heated condensate is proportioned to maintain a full spiral downflow within the enclosing structure along the tubing array while providing a central downflow along the inside of the central supporting structure.

In a flash economizer for initially separating-out the dry steam content of a blowdown effluent and for then maximizing a transfer of the heat of its heat-containing condensate to a make-up effluent such as feed water wherein:

an upright elongated enclosed processing container has an upper flashing chamber provided with a side inlet for introducing blowdown effluent therein and an upper outlet for removing flashed dry steam therefrom, has an intermediate heated condensate receiving and make up liquid circulating and heating chamber, has a lower cooled condensate receiving and discharging chamber provided with an outlet for discharging cooled condensate, and has a centrally positioned and vertically extending cylindrical inner wall member extending along its said intermediate chamber;
said inner wall member having a cross-extending closing-off top end wall provided with at least one relatively small open portion therein for restricted entry of heated condensate into said inner wall member, said inner wall member being open at its lower end into said lower chamber, said inner wall member defining thereabout an outer circular condensate-downflow area in a radially inwardly spaced relation with respect to and along a side wall of said container, a heat-exchange tubing array positioned to extend vertically along and to substantially fill said downflow area;
said array having a group of continuous individual vertically extending heat-exchange coils, each said coil having upwardly spiraled convolutions in a substantially cross-aligned and in a spaced relation with convolutions of the other coils of the group, a lower header in an upper end of said bottom chamber to which lower ends of said coils are connected to receive make-up effluent to be heated, an upper header in a lower end of said upper flashing chamber to which upper ends of said coils are connected to deliver heated make-up effluent thereto, means set to assure maintenance of a level of heated condensate in the lower end of said flashing chamber above said closing-off top end wall and said upper header and in cooperation with said open portion to provide a full and maximum downflow of heated condensate along and about said coils of the tubing array as well as a downflow along and within said inner wall member into said lower chamber, first means connected to said lower header to supply make-up effluent to be heated thereto, and second means connected to said upper header for removing heated make-up effluent therefrom.

Abstract

Claims9