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Heat Exchanger Fouling and Corrosion

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Language: en

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welcome to chemical engineering world in
00:00:02.840 00:00:02.850 this video we will discuss about how to
00:00:06.110 00:00:06.120 repair the common problems of heat
00:00:07.940 00:00:07.950 exchanger fouling and corrosion peat
00:00:11.060 00:00:11.070 exchange fouling is defined as the
00:00:13.249 00:00:13.259 accumulation and deposit of unwanted
00:00:15.440 00:00:15.450 substances that form on the external and
00:00:18.080 00:00:18.090 internal surfaces of a variety of
00:00:20.090 00:00:20.100 processing equipment called heat
00:00:22.160 00:00:22.170 exchangers this nuisance material can
00:00:25.670 00:00:25.680 include but isn't limited to algae scale
00:00:29.200 00:00:29.210 insoluble salts and suspended solids
00:00:32.770 00:00:32.780 fact is in today's industries fouling
00:00:37.340 00:00:37.350 can cause major economic drain major
00:00:40.400 00:00:40.410 industry fouling costs for
00:00:42.380 00:00:42.390 industrialized nations are estimated
00:00:44.900 00:00:44.910 over 4.4 billion dollars USD it is
00:00:48.110 00:00:48.120 estimated that 15 percent of maintenance
00:00:50.540 00:00:50.550 costs are attributed by fouling next is
00:00:54.819 00:00:54.829 some heat exchanger costs which are
00:00:57.799 00:00:57.809 associated with fouling include one
00:01:01.330 00:01:01.340 production loss associated with
00:01:03.590 00:01:03.600 efficiency deterioration two production
00:01:07.609 00:01:07.619 loss associated with unplanned and
00:01:09.649 00:01:09.659 planned operation shutdown due to
00:01:11.780 00:01:11.790 fouling three maintenance costs from
00:01:15.469 00:01:15.479 removal of heavy fouling deposits with
00:01:17.630 00:01:17.640 the use of chemicals for maintenance
00:01:21.170 00:01:21.180 costs associated with replacement of
00:01:23.719 00:01:23.729 plugged equipment cleaning costs for
00:01:26.899 00:01:26.909 industries range between $40,000 to
00:01:30.160 00:01:30.170 $50,000 per cleaning her heat exchanger
00:01:33.580 00:01:33.590 now next is Effects of fouling on heat
00:01:36.620 00:01:36.630 exchangers fouling and corrosion can
00:01:39.920 00:01:39.930 cause minor and major problems for the
00:01:42.140 00:01:42.150 majority of industries who rely on heat
00:01:44.480 00:01:44.490 exchanges to keep their operation
00:01:46.609 00:01:46.619 running efficiently some major
00:01:48.649 00:01:48.659 detrimental fouling effects for heat
00:01:50.899 00:01:50.909 exchange units include loss of
00:01:54.260 00:01:54.270 transferred heat this can be seen by the
00:01:57.109 00:01:57.119 sudden pressure increase and temperature
00:01:59.300 00:01:59.310 drop in the charge outlet
00:02:01.920 00:02:01.930 under deposit pollution and corrosion
00:02:04.460 00:02:04.470 blocked process pipes where fouling in a
00:02:08.460 00:02:08.470 heat exchanger has become hot as in
00:02:11.100 00:02:11.110 steam generators it can cause problems
00:02:13.830 00:02:13.840 with the formation of local hot spots
00:02:16.130 00:02:16.140 this can result in the ultimate failure
00:02:19.050 00:02:19.060 of the equipment common types of fouling
00:02:22.670 00:02:22.680 fouling comes in many forms some of the
00:02:26.520 00:02:26.530 most common fouling found in industries
00:02:28.770 00:02:28.780 include chemical fouling it is formed
00:02:32.760 00:02:32.770 when there are chemical changes within
00:02:34.530 00:02:34.540 the fluid these changes caused a layer
00:02:37.500 00:02:37.510 of fouling to form onto the surface of
00:02:39.720 00:02:39.730 the tube equipment one of the most
00:02:42.120 00:02:42.130 common examples of chemical fouling is
00:02:44.370 00:02:44.380 known as scaling this can be seen in a
00:02:47.340 00:02:47.350 boiler or kettle which is caused by the
00:02:49.410 00:02:49.420 hardening salt deposits on two heating
00:02:51.870 00:02:51.880 elements when the salt solubility
00:02:54.840 00:02:54.850 reduces it can cause an overall increase
00:02:57.449 00:02:57.459 in the temperature this type of fouling
00:03:00.570 00:03:00.580 can be minimised by maintaining careful
00:03:02.880 00:03:02.890 control over the temperature of the tube
00:03:04.949 00:03:04.959 wall that is in contact with the fluid
00:03:06.720 00:03:06.730 with the occurrence of this type of
00:03:08.820 00:03:08.830 fouling it can only be removed by
00:03:11.070 00:03:11.080 mechanical to scaling or chemical
00:03:13.199 00:03:13.209 treatment processes biological fouling
00:03:17.330 00:03:17.340 biological fouling is generally caused
00:03:19.680 00:03:19.690 by the overgrowth of different organisms
00:03:21.930 00:03:21.940 within the fluid this is then deposited
00:03:24.600 00:03:24.610 onto the surface area of the heat
00:03:26.789 00:03:26.799 exchanger the type of biological fouling
00:03:30.060 00:03:30.070 is typically influenced by the material
00:03:32.280 00:03:32.290 choices used one notable material that
00:03:35.580 00:03:35.590 can influence the layers of fouling is
00:03:37.620 00:03:37.630 that of non-ferrous brassey's which are
00:03:39.930 00:03:39.940 poisonous to some organisms corrosion
00:03:43.410 00:03:43.420 fouling it occurs when a layer of
00:03:46.380 00:03:46.390 corrosion materials build up on the
00:03:48.449 00:03:48.459 inorganic surface area or tubing this
00:03:51.630 00:03:51.640 creates a high thermal resistant layer
00:03:54.090 00:03:54.100 of corrosion by carefully choosing the
00:03:56.610 00:03:56.620 construction materials the effects can
00:03:59.340 00:03:59.350 be minimized
00:04:00.360 00:04:00.370 for example corrosion resistant
00:04:03.000 00:04:03.010 materials including nickel-based alloys
00:04:05.430 00:04:05.440 and stainless steel are now available to
00:04:08.160 00:04:08.170 manufacturers of heat exchange units
00:04:11.809 00:04:11.819 position fouling it occurs when fluid
00:04:15.199 00:04:15.209 particles settle onto the inorganic
00:04:17.210 00:04:17.220 surface area this is generally seen when
00:04:20.659 00:04:20.669 the velocity of fluid falls below
00:04:22.879 00:04:22.889 critical levels peat exchanger
00:04:25.879 00:04:25.889 monitoring one Inlet and outlet
00:04:29.060 00:04:29.070 temperature for cold fluid to Inlet and
00:04:33.290 00:04:33.300 outlet temperature for hot fluid three
00:04:36.469 00:04:36.479 mass flow rates for both cold and hot
00:04:39.230 00:04:39.240 fluid for hot and cold fluid pressure
00:04:43.339 00:04:43.349 change across the heat exchanger heat
00:04:46.670 00:04:46.680 exchange monitoring tips to help keep
00:04:49.939 00:04:49.949 the heat exchange system running
00:04:51.920 00:04:51.930 effectively tips are following one
00:04:55.150 00:04:55.160 understand all available data associated
00:04:58.249 00:04:58.259 with pressure flow and temperature
00:05:00.460 00:05:00.470 indicators to find out and assess what
00:05:04.640 00:05:04.650 flows pressures and temperatures are
00:05:07.400 00:05:07.410 recorded by operators on their daily
00:05:09.589 00:05:09.599 routines three continuously check the
00:05:13.730 00:05:13.740 pressure or differential pressure
00:05:15.770 00:05:15.780 tracking on the shell side or the tube
00:05:17.839 00:05:17.849 of a heat exchanger can be extremely
00:05:20.120 00:05:20.130 valuable information if the differential
00:05:22.670 00:05:22.680 pressure builds up over a period of time
00:05:25.129 00:05:25.139 it means that something is restricting
00:05:27.649 00:05:27.659 the flow for to record any temperature
00:05:31.580 00:05:31.590 day to information it is best to utilize
00:05:34.249 00:05:34.259 a handheld temperature gun infrared
00:05:37.310 00:05:37.320 temperature guns can help you monitor
00:05:39.320 00:05:39.330 the temperature of the system
00:05:40.520 00:05:40.530 effectively throughout its operation
00:05:43.210 00:05:43.220 fouling mechanisms and stages fouling
00:05:47.600 00:05:47.610 can easily be divided into a range of
00:05:49.879 00:05:49.889 different mechanisms and stages several
00:05:53.089 00:05:53.099 fouling mechanisms generally occur at
00:05:55.580 00:05:55.590 the same time with each one requiring
00:05:57.950 00:05:57.960 different techniques when it comes to
00:05:59.990 00:06:00.000 prevention these major fouling stages
00:06:03.379 00:06:03.389 and mechanisms are as follows one
00:06:06.610 00:06:06.620 initiation delay period this is the
00:06:10.490 00:06:10.500 period of clean surface area before the
00:06:12.980 00:06:12.990 fouling accumulates relatively small
00:06:15.920 00:06:15.930 accumulations of fouling can help to
00:06:18.260 00:06:18.270 improve heat transfer heat a relatively
00:06:21.230 00:06:21.240 clean surface area can help give the
00:06:23.360 00:06:23.370 heat exchanger a negative fouling
00:06:25.519 00:06:25.529 eight along with a negative total
00:06:27.469 00:06:27.479 fouling amount to particulate fouling
00:06:31.129 00:06:31.139 and particle formation flocculation and
00:06:34.099 00:06:34.109 aggregation three mass migration and
00:06:38.389 00:06:38.399 transport to fouling sites for phase
00:06:42.649 00:06:42.659 separation and deposition five growth
00:06:46.759 00:06:46.769 hardening and aging of fouling this
00:06:49.699 00:06:49.709 period sees an increase in the strength
00:06:51.859 00:06:51.869 of the deposits it also affects the
00:06:54.769 00:06:54.779 erosion and removal of fouling chemical
00:06:57.919 00:06:57.929 cleaning of fouling in heat exchanger
00:07:00.169 00:07:00.179 tubes chemical cleaning techniques range
00:07:03.259 00:07:03.269 dramatically in the chemicals used in
00:07:05.359 00:07:05.369 the results that are gained this type of
00:07:08.509 00:07:08.519 cleaning method also features many
00:07:10.279 00:07:10.289 advantages which are more beneficial
00:07:12.529 00:07:12.539 against mechanical repair these
00:07:14.959 00:07:14.969 advantages include quicker cleaning
00:07:18.259 00:07:18.269 process less labor intensity
00:07:22.860 00:07:22.870 too difficult to clean components that
00:07:24.930 00:07:24.940 mechanical cleaning may struggle to
00:07:26.700 00:07:26.710 clean chemical cleaning solutions
00:07:29.580 00:07:29.590 provide the opportunity to clean fouling
00:07:31.770 00:07:31.780 more effectively without the need to
00:07:33.390 00:07:33.400 dismantle the heat exchanger overall
00:07:36.570 00:07:36.580 this speeds up the entire process and
00:07:39.390 00:07:39.400 allows the equipment to get back up and
00:07:41.490 00:07:41.500 operational in a reduced time this can
00:07:44.700 00:07:44.710 help to save time and money associated
00:07:47.160 00:07:47.170 with taking the system up flying for a
00:07:49.260 00:07:49.270 period of time basic chemical cleaning
00:07:52.380 00:07:52.390 process the following steps are
00:07:55.320 00:07:55.330 generally used in the chemical cleaning
00:07:57.420 00:07:57.430 procedure one alkaline clean let remove
00:08:01.350 00:08:01.360 the build-up of organic materials to
00:08:04.380 00:08:04.390 rinse this is generally completed using
00:08:07.770 00:08:07.780 a high flow water flusher this removes
00:08:10.620 00:08:10.630 any loose debris along with any
00:08:12.990 00:08:13.000 remaining residue from chemicals used 3
00:08:16.800 00:08:16.810 acid cleaning this is designed to help
00:08:19.950 00:08:19.960 dissolve and soften the fouling
00:08:21.450 00:08:21.460 materials more successfully for and
00:08:24.900 00:08:24.910 rinse heat exchange your manufacturing
00:08:28.890 00:08:28.900 to combat fouling in the design process
00:08:32.370 00:08:32.380 of a heat exchanger fouling is taken
00:08:35.100 00:08:35.110 into consideration
00:08:36.560 00:08:36.570 generally when they're constructed the
00:08:39.600 00:08:39.610 manufacturer applies different methods
00:08:41.850 00:08:41.860 of construction to help provide increase
00:08:44.070 00:08:44.080 heat transfer in certain areas that may
00:08:46.590 00:08:46.600 be affected by fouling fouling
00:08:49.470 00:08:49.480 tendencies all depend on the heat
00:08:51.270 00:08:51.280 exchange a type and the fluids which are
00:08:53.700 00:08:53.710 used throughout the design and stage
00:08:56.430 00:08:56.440 many manufacturers consider the
00:08:58.710 00:08:58.720 following to help with minimizing the
00:09:00.480 00:09:00.490 occurrence and build-up of fouling where
00:09:03.540 00:09:03.550 applicable allocate more fouling fluid
00:09:06.090 00:09:06.100 to the tube side design the exchanger
00:09:09.570 00:09:09.580 for a fouling fluid velocity of three
00:09:11.790 00:09:11.800 feet per second on the shell side and
00:09:14.070 00:09:14.080 five feet per second on the

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