Note: Descriptions are shown in the official language in which they were submitted.
1159732
1 SUMMARY OF THE INVENTION
4 Present high steam pressure systems have flash steam
loss due to the pressure drop required to return the condensate
6 through steam traps or other control methods. This is due to
7 the high temperature condensate bein~ blended with a small
8 amount of 70F., new make up water that is insufficient to
9 bring the temperature and pressure of the condensate down
enough to create a pressure drop sufficient to make a steam
11 trap operate properly and overcome the loss in the condensate
12 return line. The pressure drop required to make the system
13 work will vary according to how far removed the boiler room
14 equipment is from the process plant.
An object of my invention is to provide a closed
16 pressurized main feed water system in which the pressure drop
17 is controlled without loss of any flash steam in the main
18 system because the pressure drop in the main system is attained
19 by removing steam from the feed water system and feeding it
to the lower pressure process. The pressure drop through the
21 closed system is controlled without the need for using any
22 high temperature pumps to return the condensate.
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l BRIEF DESCRIPTION OF THE DRAWING
4 Figure 1 is a schematic illustration of my closed
pressurized feed water system using a deaerator as a part of
6 the system and the one receiving the new make up water.
8 Figure 2 shows a modified closed pressurized feed
o l water system which the deaeratcr is not used
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I DESCRIPTION OF THE PREFERRED EMBODIMEN~S
4 In caxrying out my invention, I show a steam boiler
A for generating steam at a temperature of 387.89F., and a
6 pressure of 200.3 PSIG, see Figure 1. The steam is conveyed
7 through steam pipes 1 and 2 to any type of high pressure
8 process indicated schematically at B. A val~e 3 controls
9 the flow of steam into the high pressure process B. The
condensate leaving the high pressure process B, through the
11 line 4 has a temperature of 387.89F., and it is forced through
12 a steam trap C shown diagrammatically in Figure 1. A conden-
13 sate line 5 leads from the steam trap C to a feed water system
14 shown at D. A boiler return line 6 including a;pump E, returns
the condensate back to the boiler A to complete the closed
16 circuit in my system. Processes that have a low percentage of
17 lost steam require a low percentage of new make up water.
18 The following illustration will be helpful. Assume
19 an operating steam pressure at 387.89F., and 200.3 PSIG, and
we wish to return 96.68% as a condensate back to the boiler A
21at 387.89F., and add 3.32% new make up water at 70~F.
22Return condensate 387.89F. X 96.68~ = 37501.2
23Make up water 70F. X _3.32% = 232.4
24100% 37733.6
25Divide: 37733.6.100 = 377.3~F, at approximate 179 PSIG.
26200.3 PSIG (original steam pressure) -179 PSIG-21.3
27PSIG pressure drop.
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1159732
1 This is an insufficient pressure drop to make the
2 closed system operate.
3 The 179 PSIG steam pressure, if flashed down to a
4 ten pound pressure will result in a flash steam loss of about
14~ of the total steam produced. With my system of no flash
6 steam loss this waste of 14~ of the steam is saved.
7 A condensate of 200.3 PSIG flashed down to 375F at
8 170 PSIG = 3.32~.
9 375F X 96.68 = 36255
70F X 3.32 = 232
11 100% 364.87 ~ 365=150 PSIG
12 200.3 PSIG - 150 PSIG = 50.3 PSIG drop.
13 There are pressurized condensate systems in use that
14 have high temperature transfer pumps in the system to return
the condensate back to the pressurized receivers or boiler.
16 These systems require a pump and closed condensate receivers
17 in the plant for each operating pressure in the process.
18 With my closed high steam pressure system the flash
19 steam produced from my pressuri~ed receiver in the boiler room
will control the pressure drop from the discharge of the traps
21 to the pressurized receiver from all of the high pressure
22 processes so that no pumps will be required. In Figure 1, I
23 show the high pressure process B and the steam trap C. The
24 hot- condensate in the pipe ~ from the steam trap flows into
the feed water system D and steam will be flashed from the
26 condensate within feed water system.
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1 The flash steam removed from the feed water system D
2 flows through a pipe 21 and then through a pipe 7 to a low
3 pressure process G, and this steam is controlled by a valve 6,
4 see Figure 1. A steam trap H controls the hot condensate from
the low pressure process G and directs this condensate in a
6 line 9 to the deaerator F. The type of deaerator used is the
7 one disclosed in my U.S. Patent No. 3,487,611, issued
8 January 6, 1970 and entitled, "Spray Flow Deaerator." The
9 water level in the deaerator F is shown at 10 and a pump ~ in
a line 11 removes the condensate from the deaerator and delivers
11 it to the feed water system D and from there the condensate is
12 returned to the boiler A by the line 6 and pump E.
13 New make up water at 70F., is delivered to the
14 deaerator F as required by a fresh water line 12 controlled
; by a valve 13. The fresh watex line 12 enters the deaerator
16 and has a spray nozzle 14 that causes the fresh water to enter
17 the hot condensate in the deaerator. The deaerator F has an
18 outlet pipe 15 for pe~mitting the non-condensable gases to
19 escape ~rom the deaerator. Also, steam can be fed from the
feed water system D into the deaerator F by a line 16 that is
21 controlled by a valve 17. There is a branch steam line 18
~ 22 connecting the steam line 1 to the feed water system D by a
-~ 23 line 21 and a valve 19 is placed in the line 18. Figure 1
-~ 24 further shows another steam line 20 leading from the steam
pipe 7 for conveying steam that is used for any purpose where
26 there is no condensate return back to the boiler. The purpose
~1 27 of the steam line 18 leading from the boiler A and steam
28 pipe 1 to the feed water system D is to control the steam
29 pressure in the feed water system D and add sufficient steam
for a stable operation.
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1 The present closed pressuxized feed water system can
2 ¦ be applied to any process equipment from which condensate is
3 ¦ to be returned to the steam boiler A without any loss from
4 ¦ flash steam regardless of the type of condensate drainage
5 ¦ installed such as steam trap systems, closed cascading
6 ¦ systems or systems using orifices. When condensate is
7 ¦ removed from a process in a system that also removes some
8 ¦ steam in order to remove the carbon dioxide CO2, my closed
9 ¦ system will salvage this steam as it is returned to the pressu-
10 ¦ rized receiver and then the steam is reused at a lower opera-
ll ¦ ting steam pressure. There are many systems in operation
12 ¦ that are flashing steam from the hot condensate in the process
13 ¦ plant through flash receivers, but none that first take the
14 ¦ condensate back to the feed water receiver in the boiler room
15 ¦ and then flash of the steam in the feed water system D to
16 ¦ create a pressure drop so that the condensate can be returned
17 ¦ to the feed water system without the use of any pumping. Then
1 18 ¦ the steam is returned through the separate line 7 for use at
l9 ¦ the lower pressure process G. My system can be applied to any
20¦ process that has a condensate return such as paper corrugators,
21 ¦ paper mills, plywood dryers, rendering plants, textile plants,
22 ¦ rubber plants, chemical plants, etc.
:: 23 ¦ With my present closed pressurized system the
24 ¦ pressure drop is controlled without any steam flash loss and
25 ¦ this is due to supplying this flash steam from the feed water
j~ 26 ¦ system D through the line 7 to the lower pressure process G,
1 27 ¦ as shown in Figure l. The pressure drop in the feed water
28 ¦ system D is sufficient to cause the steam trap C to operate
29 ¦ and return the hot condensate to the feed water system through
30 ¦ the line 5. The flash steam plus steam from the boiler A can
31 be supplied when required through the line 18 controlled by
32 ¦ the valve 19.
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1 In order to produce the best quality steam from the
2 boiler A it is better to deaerate the new make up water and
3 then add this water below the water level in the feed water
4 system D so that the corresponding water temperature in the
pressurized receiver will be below the corresponding pressure
6 to prevent the boiler feed water pump E from flashing.
7 The novelty of my closed pressurized steam and conden-
8 sate system is to create a maximum pressure drop in the boiler
9 feed water system with a minimum amount of new make up water
being added. A balanced pressure line 21 interconnects the
11 pressurized feed water system D, and the lower operating pres-
12 sure steam line 7 to insure a stable operation. A steam and
13 gas removal line 22 connects to the process B outlet line 4
14 and communicates with the feed water system D and its flow is
controlled by a valve 23 for increasing the efficiency of heat
16 transfer in the process B.
17 In Figure 2 I show a slightly modified form of the
18 closed system shown in Figure l. The deaerator F, shown in
19 Figure l, is not used in Figure 2. The new make up water is
added directly to the feed water system D through a fresh
21 water pipe 30. The closed modified system of Figure 2 in all
22 other respects is the same as that shown in Figure l and
23 similar parts are given like reference numerals, etc. A gas
24 removal line 31 connects with the feed water system D for
Z5 removing gases from the system.
26 Although I mention a trap C in F;igure l, I could
27 use an orifice which controls the condensate flow or a control
28 valve with a liquid level control. I therefore use the word
29 steam trap in a generic sense to include these other controls.
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