Quit Stalling! Avoid Heat Exchanger Stalling with Armstrong International

WEBVTT
Kind: captions
Language: en

00:00:06.430
well hello my name is Randy Waldron with
00:00:09.220 00:00:09.230 Armstrong International and today we
00:00:11.379 00:00:11.389 want to take a few minutes to clarify
00:00:14.070 00:00:14.080 some issues that are common problems in
00:00:17.890 00:00:17.900 heat exchanger drainage throughout a
00:00:20.710 00:00:20.720 multiple of different industries we're
00:00:23.920 00:00:23.930 lucky enough today to have a working
00:00:28.689 00:00:28.699 model of a glassy exchanger that most
00:00:33.040 00:00:33.050 process engineers don't actually get to
00:00:35.170 00:00:35.180 see what happens inside the piping or
00:00:37.030 00:00:37.040 inside the heat exchange equipment so
00:00:39.459 00:00:39.469 what we're going to do is kind of run
00:00:40.930 00:00:40.940 you through the system that we have and
00:00:42.760 00:00:42.770 then we'll go through some different
00:00:44.440 00:00:44.450 variables that take place in the process
00:00:46.660 00:00:46.670 loop that will hopefully allow you to
00:00:51.160 00:00:51.170 troubleshoot systems better evaluate
00:00:54.279 00:00:54.289 potential issues that they have and come
00:00:57.760 00:00:57.770 up with intelligent solutions to solve
00:01:00.340 00:01:00.350 their problems to start off with to let
00:01:03.610 00:01:03.620 you know what we have is we have a glass
00:01:05.499 00:01:05.509 shell and tube heat exchanger in this
00:01:08.260 00:01:08.270 case we have a process fluid coming in
00:01:12.310 00:01:12.320 in this case which is water flowing
00:01:16.060 00:01:16.070 through the tubes we have the process in
00:01:19.719 00:01:19.729 the tubes and the steam in the shell the
00:01:23.080 00:01:23.090 water coming in on the right hand side
00:01:25.060 00:01:25.070 as you can see is a variable flow we
00:01:29.109 00:01:29.119 have the ability to vary that flow just
00:01:32.440 00:01:32.450 like you would see a different process
00:01:34.149 00:01:34.159 demand on any kind of heat exchanger the
00:01:37.210 00:01:37.220 beauty about the lesson we're going to
00:01:38.649 00:01:38.659 learn today is that heat exchange
00:01:41.530 00:01:41.540 equipment the variables we're going to
00:01:43.749 00:01:43.759 talk about are common whether you're
00:01:47.289 00:01:47.299 heating air or whether you're heating
00:01:49.660 00:01:49.670 glycol or ethylene okay the variables
00:01:54.399 00:01:54.409 that we're going to point out are always
00:01:56.679 00:01:56.689 areas that can change within the system
00:01:59.950 00:01:59.960 and when those changes take place they
00:02:03.520 00:02:03.530 have different effects on both the
00:02:05.920 00:02:05.930 equipment itself and the downstream
00:02:07.749 00:02:07.759 equipment like our traps like our pumps
00:02:09.880 00:02:09.890 and the other products that we made we
00:02:14.170 00:02:14.180 are feeding the shell side of this heat
00:02:16.479 00:02:16.489 exchanger with saturated steam
00:02:19.930 00:02:19.940 we're coming off of a 50 pound header
00:02:25.930 00:02:25.940 dropping down coming through one of our
00:02:29.350 00:02:29.360 control valves where the control valve
00:02:34.040 00:02:34.050 has the ability to modulate the steam
00:02:37.640 00:02:37.650 flow based on the process demand we have
00:02:41.890 00:02:41.900 inherently built in a control panel over
00:02:45.620 00:02:45.630 here that allows us to stroke this valve
00:02:48.680 00:02:48.690 and simulate different process variables
00:02:51.949 00:02:51.959 within the loop we come up we feed the
00:02:56.030 00:02:56.040 top side of the exchanger over here on
00:02:58.820 00:02:58.830 the right-hand side and that's where the
00:03:02.240 00:03:02.250 steam comes in to the top side of the
00:03:04.010 00:03:04.020 shell
00:03:05.740 00:03:05.750 we then of course have the condensate
00:03:08.090 00:03:08.100 outlet coming right out the bottom in
00:03:12.650 00:03:12.660 the case that we have right now the
00:03:14.750 00:03:14.760 scenario that we're simulating is
00:03:17.090 00:03:17.100 strictly going from the exchanger over
00:03:20.630 00:03:20.640 to some type of steam trap whether that
00:03:24.740 00:03:24.750 be an F and T trap that we have at the
00:03:26.780 00:03:26.790 top a thermostatic trap that we have in
00:03:29.870 00:03:29.880 the middle the IB trap or at the bottom
00:03:33.890 00:03:33.900 a northeast height trap we have the
00:03:39.560 00:03:39.570 ability in this system to open another
00:03:43.310 00:03:43.320 motorized valve that allows us to feed
00:03:45.740 00:03:45.750 our pumping trap system now that we've
00:03:49.640 00:03:49.650 kind of laid out what our piping
00:03:50.990 00:03:51.000 arrangement is let's talk about some of
00:03:54.020 00:03:54.030 the problems that we commonly incur with
00:03:58.009 00:03:58.019 exchangers one is variable flow rates as
00:04:02.410 00:04:02.420 we look at right now what the condensing
00:04:05.270 00:04:05.280 rate is you can notice that as you see
00:04:09.590 00:04:09.600 the liquid going through the tubes
00:04:11.330 00:04:11.340 you'll see that there's continual amount
00:04:14.300 00:04:14.310 of bubbles that travel through those
00:04:17.270 00:04:17.280 tubes
00:04:17.960 00:04:17.970 that's entrained air in the actual
00:04:21.830 00:04:21.840 process flow okay one reason it's so
00:04:25.520 00:04:25.530 important to get it out over here with
00:04:28.760 00:04:28.770 our ball float air vent on the process
00:04:30.770 00:04:30.780 side of the
00:04:31.350 00:04:31.360 livvie what we're going to do now is I'm
00:04:36.839 00:04:36.849 basically going to increase a little bit
00:04:42.600 00:04:42.610 of pressure on the bundle you'll note
00:04:45.360 00:04:45.370 that right now the gauge is showing an
00:04:48.629 00:04:48.639 outlet pressure on the heat exchanger of
00:04:52.110 00:04:52.120 five pounds let me take a minute to
00:04:56.159 00:04:56.169 emphasize the importance of where
00:04:59.490 00:04:59.500 pressures are taken as we try to
00:05:02.540 00:05:02.550 troubleshoot these systems the inlet
00:05:06.719 00:05:06.729 pressure that spent to a heat exchanger
00:05:08.939 00:05:08.949 is normally always dependent on what the
00:05:13.409 00:05:13.419 process flow is telling this control
00:05:15.689 00:05:15.699 valve then it needs however what affects
00:05:21.209 00:05:21.219 all of this equipment down here whether
00:05:25.800 00:05:25.810 it's steam traps
00:05:26.999 00:05:27.009 whether it's pumping traps is the actual
00:05:31.080 00:05:31.090 outlet pressure of the exchanger the
00:05:35.129 00:05:35.139 outlet pressure varies based on how much
00:05:40.559 00:05:40.569 process flow we're trying to heat how
00:05:44.369 00:05:44.379 much surface area we have to achieve
00:05:49.019 00:05:49.029 that heat transfer and also by how much
00:05:56.779 00:05:56.789 back pressure we have here that affects
00:06:00.809 00:06:00.819 the total throughput of any of this
00:06:04.290 00:06:04.300 equipment so we have to understand what
00:06:08.219 00:06:08.229 those variables are to make a proper
00:06:11.399 00:06:11.409 determination of why we have issues or
00:06:13.709 00:06:13.719 have potential issues okay as we go
00:06:17.909 00:06:17.919 through the traps we see that we have
00:06:20.189 00:06:20.199 five pounds on the inlet and right now
00:06:22.829 00:06:22.839 we're going to zero PSIG on the outlet
00:06:26.490 00:06:26.500 side that's because we're going to drain
00:06:29.339 00:06:29.349 as we continually try to help our
00:06:32.760 00:06:32.770 customers optimize these systems we know
00:06:35.579 00:06:35.589 that hot ton and sayd is worth a lot of
00:06:38.730 00:06:38.740 money
00:06:39.170 00:06:39.180 so typically we always try to recommend
00:06:42.290 00:06:42.300 capturing this Commons
00:06:45.000 00:06:45.010 but when we start capturing condensate
00:06:48.010 00:06:48.020 that also creates other issues for us
00:06:50.140 00:06:50.150 okay
00:06:51.450 00:06:51.460 like back pressure in low pressure
00:06:55.330 00:06:55.340 systems back pressure is one of the most
00:06:58.870 00:06:58.880 common problems that we incur when we
00:07:04.780 00:07:04.790 try to evacuate condensate from a steam
00:07:07.060 00:07:07.070 space what we're going to do now is I'm
00:07:11.920 00:07:11.930 going to slowly valve out this
00:07:15.909 00:07:15.919 atmospheric mouth and we're going to
00:07:20.860 00:07:20.870 slowly as you can see start to build up
00:07:23.230 00:07:23.240 level in the condensate return piping as
00:07:27.420 00:07:27.430 you see the condensate being drained
00:07:31.890 00:07:31.900 through the trap the differential
00:07:36.760 00:07:36.770 initially on this trap was five pounds
00:07:39.730 00:07:39.740 we had five pounds on the outlet of the
00:07:41.830 00:07:41.840 heater coming into the trap
00:07:43.800 00:07:43.810 we had zero PSIG at the drain right now
00:07:49.630 00:07:49.640 what we've just done by valving in the
00:07:52.480 00:07:52.490 condensate header is we're slowly
00:07:54.880 00:07:54.890 inducing back pressure on the trap we're
00:07:59.260 00:07:59.270 inducing the back pressure by allowing
00:08:00.909 00:08:00.919 the liquid head to generate look at the
00:08:03.279 00:08:03.289 level down the level is almost to the
00:08:05.830 00:08:05.840 top
00:08:06.450 00:08:06.460 but remember one PSI for every two feet
00:08:09.540 00:08:09.550 there's a foot there's a foot there's a
00:08:12.850 00:08:12.860 foot there's a foot so we're slowly
00:08:16.600 00:08:16.610 cutting back on the differential across
00:08:19.029 00:08:19.039 this trap by generating that amount of
00:08:22.180 00:08:22.190 liquid head the other thing we always
00:08:26.560 00:08:26.570 have to remember is not only do we have
00:08:29.800 00:08:29.810 liquid head in the vertical rise but we
00:08:33.219 00:08:33.229 also have the pressure that exists in
00:08:36.579 00:08:36.589 the condensate header itself that we run
00:08:40.140 00:08:40.150 usually in an overhead return scenario
00:08:44.130 00:08:44.140 what we want to do now is I want to
00:08:48.370 00:08:48.380 slowly actuate a valve that will allow
00:08:52.660 00:08:52.670 us to observe
00:08:55.070 00:08:55.080 our pumping track system and how we can
00:08:59.060 00:08:59.070 optimize those exchangers by allowing
00:09:02.660 00:09:02.670 them to run in the lowest possible
00:09:04.100 00:09:04.110 pressure again as steam experts we all
00:09:08.990 00:09:09.000 understand that the latent heat content
00:09:11.600 00:09:11.610 in lower pressure steam gives us a lot
00:09:15.260 00:09:15.270 more heat value per pound then does the
00:09:18.140 00:09:18.150 higher pressure steam so what it makes
00:09:21.410 00:09:21.420 sense for us to do is to run those
00:09:24.410 00:09:24.420 exchangers at the lowest possible
00:09:26.450 00:09:26.460 pressure to optimize their performance
00:09:29.410 00:09:29.420 okay what we wanted to do was continue
00:09:32.600 00:09:32.610 and show you what we've done to actually
00:09:36.070 00:09:36.080 equalize our pumping system into the
00:09:39.800 00:09:39.810 outlet pressure of an exchanger what we
00:09:43.010 00:09:43.020 wanted to show is graphically show you
00:09:45.230 00:09:45.240 that our ability to continually drain an
00:09:49.870 00:09:49.880 exchanger regardless of its condensing
00:09:53.000 00:09:53.010 rate regardless of its outlet pressure
00:09:55.840 00:09:55.850 regardless of all of those variables
00:09:58.250 00:09:58.260 that we just discussed that can cause
00:09:59.960 00:09:59.970 issues if we engineer the downstream
00:10:03.320 00:10:03.330 side of these exchanges correctly we can
00:10:06.170 00:10:06.180 ensure that we never corrode the tube
00:10:08.960 00:10:08.970 bundles because we always keep the
00:10:12.350 00:10:12.360 surface area dry on the exchange that's
00:10:16.190 00:10:16.200 a very very large value to all of our
00:10:18.770 00:10:18.780 customers regardless of the heat
00:10:22.010 00:10:22.020 transfer setup whether it's an air coal
00:10:23.870 00:10:23.880 or a heat exchanger or reboiler okay
00:10:27.410 00:10:27.420 what we've done was we actuated the
00:10:29.900 00:10:29.910 valve on the outlet of the exchanger
00:10:32.390 00:10:32.400 that allows us to free drain down into a
00:10:37.100 00:10:37.110 closed-loop pump track scenario we
00:10:42.800 00:10:42.810 realized that now we have products that
00:10:46.510 00:10:46.520 incorporate both the pump and the trap
00:10:50.090 00:10:50.100 together however for us to graphically
00:10:53.210 00:10:53.220 and visually allow you to see what takes
00:10:58.460 00:10:58.470 place in these processes we wanted to
00:11:01.070 00:11:01.080 keep this separate so you can see what
00:11:04.820 00:11:04.830 happens with the traps and how the pumps
00:11:07.550 00:11:07.560 were
00:11:08.120 00:11:08.130 in conjunction with the traps right now
00:11:11.090 00:11:11.100 you'll see the outlet pressure of the
00:11:12.620 00:11:12.630 exchangers at five pounds like it has
00:11:14.900 00:11:14.910 been no different we have five pounds
00:11:18.080 00:11:18.090 coming in we have five pounds coming
00:11:20.450 00:11:20.460 around and we have five pounds that
00:11:24.530 00:11:24.540 should be coming right to the steam trap
00:11:26.360 00:11:26.370 okay and remember this this is critical
00:11:30.350 00:11:30.360 it's a common mistake that even some
00:11:33.710 00:11:33.720 seasoned veterans may I don't care what
00:11:36.680 00:11:36.690 pressure you feed that exchanger what
00:11:39.740 00:11:39.750 matters to us is what's on the outlet of
00:11:44.030 00:11:44.040 that exchanger okay we can see that we
00:11:48.500 00:11:48.510 have a float and thermostatic trap on
00:11:50.840 00:11:50.850 the downstream side of the pump this
00:11:53.300 00:11:53.310 trap is installed so that if the outlet
00:11:58.040 00:11:58.050 pressure of this exchanger coming
00:12:01.160 00:12:01.170 through the system exceeds the back
00:12:04.100 00:12:04.110 pressure that we have trying to lift
00:12:06.920 00:12:06.930 this condensate and get into the header
00:12:09.760 00:12:09.770 we would have steam flowing all the way
00:12:13.160 00:12:13.170 through this if we had no steam trap as
00:12:16.750 00:12:16.760 you see now we have about eight feet of
00:12:21.830 00:12:21.840 lift roughly that's about four pounds
00:12:25.210 00:12:25.220 right on the outlet we're at about four
00:12:27.830 00:12:27.840 pounds so you can see through the flow
00:12:33.650 00:12:33.660 indicator that we have no flow through
00:12:36.650 00:12:36.660 the trap into the vertical rise into the
00:12:39.590 00:12:39.600 header we're currently at what we term
00:12:44.390 00:12:44.400 as a stall condition but in essence the
00:12:49.850 00:12:49.860 technical term for it is there is lack
00:12:52.610 00:12:52.620 of differential pressure there is no
00:12:54.650 00:12:54.660 pressure difference if anything we have
00:12:58.700 00:12:58.710 more back pressure than we have inlet
00:13:01.880 00:13:01.890 pressure to the trap so regardless of
00:13:05.420 00:13:05.430 how big this trap is when there's no
00:13:08.750 00:13:08.760 difference in pressure to push liquid
00:13:11.210 00:13:11.220 through it this trap will not operate
00:13:14.180 00:13:14.190 correctly on this
00:13:16.530 00:13:16.540 so what we're doing is we're continually
00:13:19.629 00:13:19.639 condensing in the exchanger you'll see
00:13:22.509 00:13:22.519 that we're at four pounds and four
00:13:23.980 00:13:23.990 pounds what I'm going to do now is
00:13:27.699 00:13:27.709 slowly modulates the steam control valve
00:13:32.889 00:13:32.899 to decrease the amount of steam flow to
00:13:37.900 00:13:37.910 the exchangers because we're going to
00:13:40.389 00:13:40.399 drop this outlet pressure and we want to
00:13:43.299 00:13:43.309 demonstrate to you that this system
00:13:46.600 00:13:46.610 allows the exchanger to run at either
00:13:49.419 00:13:49.429 five pounds a hundred pounds or in a
00:13:54.009 00:13:54.019 negative pressure because there goes the
00:13:57.790 00:13:57.800 pump I believe it just cycled you can
00:14:01.419 00:14:01.429 see now that there is flow coming in to
00:14:04.960 00:14:04.970 the trap and as we slowly start to build
00:14:10.509 00:14:10.519 pressure in the pump body you'll see the
00:14:14.799 00:14:14.809 pressure slowly build here as that
00:14:17.410 00:14:17.420 happens we will continually pump liquid
00:14:20.460 00:14:20.470 into and out of the trap and into the
00:14:23.710 00:14:23.720 header and we should as the pressure
00:14:27.249 00:14:27.259 bills in the pump we should see a flow
00:14:35.230 00:14:35.240 through the vertical rise here but note
00:14:38.110 00:14:38.120 this this is very important why is it
00:14:40.720 00:14:40.730 important for the reservoir on a pumping
00:14:42.759 00:14:42.769 trap because even though we are now in
00:14:46.179 00:14:46.189 the pump out cycle of the pump which
00:14:48.970 00:14:48.980 close the inlet check valve we're now
00:14:53.110 00:14:53.120 still condensing the same rate of liquid
00:14:55.509 00:14:55.519 in the heat exchanger we have to have an
00:14:59.289 00:14:59.299 adequate reservoir to take the amount of
00:15:03.879 00:15:03.889 liquid that we condensed in the
00:15:05.049 00:15:05.059 exchanger and allow it to gather
00:15:07.239 00:15:07.249 someplace while the pump is pumping the
00:15:10.629 00:15:10.639 liquid out through the steam trap okay
00:15:13.949 00:15:13.959 what you're going to see is the
00:15:17.199 00:15:17.209 continual rays of level in the glass
00:15:20.879 00:15:20.889 reservoir piping as we're trying to pump
00:15:25.059 00:15:25.069 out through the trap and in
00:15:26.900 00:15:26.910 the maternity header once we go through
00:15:30.620 00:15:30.630 this pump-out cycle I will go ahead then
00:15:34.670 00:15:34.680 and we'll go ahead and cycle the
00:15:36.260 00:15:36.270 exchanger to go into vacuum and show you
00:15:39.410 00:15:39.420 that it still basically allows you 100%
00:15:42.740 00:15:42.750 turn down on the rates and the variables
00:15:46.360 00:15:46.370 by allowing it to drain regardless of
00:15:48.980 00:15:48.990 what that pressure is note that the
00:15:52.460 00:15:52.470 steam pressure from the regulating valve
00:15:55.180 00:15:55.190 going into the pump track system that we
00:15:59.510 00:15:59.520 have it's set at about 8 pounds okay
00:16:04.930 00:16:04.940 so we're building we're feeding about 8
00:16:08.630 00:16:08.640 pounds into the pump note that now the
00:16:12.980 00:16:12.990 pressure is up to about 6 just for you
00:16:17.090 00:16:17.100 guys that are selling pumps all the time
00:16:18.770 00:16:18.780 remember this typically the pump case
00:16:23.360 00:16:23.370 pressure will never increase over about
00:16:28.250 00:16:28.260 10 pounds of what your total bike
00:16:30.980 00:16:30.990 pressure is where we're trying to pump
00:16:32.840 00:16:32.850 the liquid to because by the time the
00:16:35.600 00:16:35.610 pressure in the pump case builds to that
00:16:37.880 00:16:37.890 level the liquids already gone it's
00:16:40.340 00:16:40.350 already moving remember we had no
00:16:43.040 00:16:43.050 differential pressure we were stalled
00:16:45.730 00:16:45.740 we're inducing differential pressure now
00:16:49.070 00:16:49.080 by the high pressure feed into the pump
00:16:53.410 00:16:53.420 pressurizing up over the back pressure
00:16:57.160 00:16:57.170 coming in pushing it out through the
00:17:00.110 00:17:00.120 float trap and up into the header now
00:17:04.010 00:17:04.020 the pump out cycle is a fairly long
00:17:07.940 00:17:07.950 cycle in this demo simply because we
00:17:11.510 00:17:11.520 wanted you to have the last drive
00:17:14.650 00:17:14.660 typically the track downstream of your
00:17:17.930 00:17:17.940 pump should be able to take the max
00:17:21.950 00:17:21.960 condensate rate of the exchanger at a
00:17:24.170 00:17:24.180 quarter-pound differential so you don't
00:17:26.570 00:17:26.580 bottleneck the pump out cycle of the
00:17:29.660 00:17:29.670 pump because what happens when we
00:17:32.060 00:17:32.070 bottleneck the pump out cycle bottom
00:17:34.790 00:17:34.800 line is it takes more reservoir because
00:17:37.820 00:17:37.830 I have
00:17:39.130 00:17:39.140 more time for this to continue
00:17:40.840 00:17:40.850 condensing and I have to have a place
00:17:43.300 00:17:43.310 for more of this condensate together so
00:17:47.500 00:17:47.510 the function of the trap dictates what
00:17:51.340 00:17:51.350 the reservoir is the motive pressure to
00:17:56.350 00:17:56.360 the pumps dictate what the trap is so we
00:18:01.360 00:18:01.370 have to take into consideration all of
00:18:02.980 00:18:02.990 these things as we engineer a total
00:18:05.890 00:18:05.900 condensate return solution for the
00:18:09.070 00:18:09.080 exchanges
Office location
Engineering company LOTUS®
Russia, Ekaterinburg, Lunacharskogo street, 240/12

Phone: +7 343 216 77 75

E-mail: info@lotus1.ru

Sales phone

Russia: +7 343 216 77 75

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