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Refinery Crude Oil Distillation Process Complete Full HD

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Language: en

00:00:00.210
one of the key elements of many process
00:00:02.929 00:00:02.939 plants is a distillation system it's
00:00:05.450 00:00:05.460 important for operators to understand
00:00:07.220 00:00:07.230 how distillation systems work because
00:00:09.650 00:00:09.660 it's part of their job to make sure the
00:00:11.240 00:00:11.250 systems run properly the purpose of any
00:00:14.060 00:00:14.070 distillation system is to separate a
00:00:16.250 00:00:16.260 liquid mixture into two or more
00:00:18.109 00:00:18.119 components the separation takes place in
00:00:20.900 00:00:20.910 a distillation column or tower the
00:00:23.630 00:00:23.640 liquid mixture is called feed or charge
00:00:25.880 00:00:25.890 and the components into which it
00:00:27.980 00:00:27.990 separated are called cuts or fractions
00:00:30.580 00:00:30.590 let's take a look at a simplified
00:00:32.650 00:00:32.660 representation of a distillation system
00:00:34.610 00:00:34.620 in this example the feed is stored in a
00:00:38.540 00:00:38.550 tank during operation a pump is used to
00:00:41.990 00:00:42.000 move the feed from the tank to a pre
00:00:43.670 00:00:43.680 heater in the pre heater the mixture is
00:00:47.000 00:00:47.010 heated under pressure to just below its
00:00:48.979 00:00:48.989 boiling point the pressure in the tower
00:00:51.500 00:00:51.510 is lower than the pressure in the pre
00:00:53.420 00:00:53.430 heater so when the feed enters the tower
00:00:55.939 00:00:55.949 it starts to boil the vapors from the
00:00:59.180 00:00:59.190 boiling liquid which primarily contained
00:01:01.549 00:01:01.559 the lighter components in the feed rise
00:01:03.979 00:01:03.989 in the tower the remaining liquid which
00:01:07.730 00:01:07.740 consists primarily of the heavier
00:01:09.380 00:01:09.390 components in the feed moves down the
00:01:11.600 00:01:11.610 tower and collects at the bottom some of
00:01:14.840 00:01:14.850 this liquid is drawn off as the bottoms
00:01:16.789 00:01:16.799 product and some of it's routed to a
00:01:18.950 00:01:18.960 device called a reboiler which is
00:01:21.109 00:01:21.119 connected to the bottom of the tower the
00:01:23.870 00:01:23.880 reboiler is usually a heat exchanger
00:01:25.969 00:01:25.979 that's designed to vaporize the lighter
00:01:28.010 00:01:28.020 components that remain in the liquid
00:01:29.749 00:01:29.759 from the bottom of the tower vapors from
00:01:32.810 00:01:32.820 the reboiler or in some cases a mixture
00:01:35.420 00:01:35.430 of vapors and liquid re-enter the tower
00:01:38.080 00:01:38.090 the vapors then rise up in the tower
00:01:40.929 00:01:40.939 these vapors and the heat they contain
00:01:43.880 00:01:43.890 are often referred to as boil up the hot
00:01:47.569 00:01:47.579 boil up provides heat that's needed for
00:01:49.580 00:01:49.590 the distillation process to take place
00:01:51.139 00:01:51.149 in the tower the vapors that rise up in
00:01:54.469 00:01:54.479 the tower are routed to a condenser the
00:01:57.469 00:01:57.479 purpose of the condenser is to cool and
00:01:59.600 00:01:59.610 condense the vapors into liquid from the
00:02:02.660 00:02:02.670 condenser the liquid flows into a
00:02:04.609 00:02:04.619 receiver or accumulator the receiver
00:02:07.280 00:02:07.290 provides a reservoir for the liquid part
00:02:10.880 00:02:10.890 of the liquid from the receiver is
00:02:12.380 00:02:12.390 pumped back
00:02:13.400 00:02:13.410 to the top of the tower and part of it
00:02:15.500 00:02:15.510 is drawn off as the towers overhead
00:02:17.720 00:02:17.730 product well we've just looked at one
00:02:20.930 00:02:20.940 simple example of a distillation system
00:02:22.840 00:02:22.850 not all distillation systems are the
00:02:25.340 00:02:25.350 same but most of them have the basic
00:02:27.620 00:02:27.630 equipment that we've just seen at the
00:02:30.170 00:02:30.180 heart of a distillation system is the
00:02:32.150 00:02:32.160 distillation tower basically a
00:02:34.700 00:02:34.710 distillation tower is a series of
00:02:36.680 00:02:36.690 distillation processes or stills stacked
00:02:39.530 00:02:39.540 on top of each other the process of
00:02:42.320 00:02:42.330 distillation is sometimes referred to as
00:02:44.260 00:02:44.270 fractional distillation or fractionation
00:02:47.030 00:02:47.040 and distillation towers are sometimes
00:02:49.850 00:02:49.860 called fractionators fractionation is
00:02:53.090 00:02:53.100 distillation that occurs at different
00:02:54.440 00:02:54.450 levels in a tower this is a simplified
00:02:58.640 00:02:58.650 illustration of the inside of one type
00:03:00.530 00:03:00.540 of distillation Tower this tower uses
00:03:03.230 00:03:03.240 trays called sieve trays to separate
00:03:05.360 00:03:05.370 vapors and liquid the trays are spaced
00:03:07.910 00:03:07.920 throughout the tower
00:03:08.980 00:03:08.990 they're called sieve trays because they
00:03:11.390 00:03:11.400 have many openings in them like a sieve
00:03:13.510 00:03:13.520 here's a closer view of some of the
00:03:15.950 00:03:15.960 trays we've exaggerated the size of the
00:03:18.650 00:03:18.660 openings to make them easier to see the
00:03:21.440 00:03:21.450 openings in the trays allow vapors to
00:03:23.150 00:03:23.160 rise through the trays on their way up
00:03:24.800 00:03:24.810 the tower each tray is also designed to
00:03:28.490 00:03:28.500 hold liquid dams or Weir's on each tray
00:03:31.550 00:03:31.560 allow liquid to build up on the tray
00:03:33.970 00:03:33.980 liquid that overflows the Weir's flows
00:03:36.620 00:03:36.630 into downcomers the downcomers channel
00:03:39.500 00:03:39.510 the liquid from tray to tray down the
00:03:41.300 00:03:41.310 tower when the upward moving vapors and
00:03:44.420 00:03:44.430 the downward flowing liquid come in
00:03:46.790 00:03:46.800 contact on each tray the vapors transfer
00:03:49.640 00:03:49.650 some of their heat to the liquid two
00:03:51.410 00:03:51.420 things happen the heavier components of
00:03:53.960 00:03:53.970 the vapors become cooler and condense
00:03:55.850 00:03:55.860 into liquid and the lighter components
00:03:58.010 00:03:58.020 of the liquid boil the vapors then rise
00:04:00.860 00:04:00.870 toward the next tray as this process
00:04:03.500 00:04:03.510 continues the rising vapors contain a
00:04:05.900 00:04:05.910 higher concentration of lighter
00:04:07.460 00:04:07.470 components and a lower concentration of
00:04:10.040 00:04:10.050 heavier components so this is how the
00:04:14.030 00:04:14.040 distillation process is repeated on each
00:04:16.250 00:04:16.260 tray as the vapors rise through the
00:04:18.289 00:04:18.299 tower now not every distillation tower
00:04:20.990 00:04:21.000 is designed in the exact same way
00:04:22.810 00:04:22.820 however every tower can be divided into
00:04:25.909 00:04:25.919 three basics
00:04:27.640 00:04:27.650 the middle section is where the feed
00:04:30.050 00:04:30.060 enters the tower and part of the feed
00:04:31.969 00:04:31.979 vaporizes this vaporization is commonly
00:04:35.150 00:04:35.160 known as flashing so this section of the
00:04:37.790 00:04:37.800 tower is often called the flash zone the
00:04:41.120 00:04:41.130 section above the flash zone is called
00:04:42.920 00:04:42.930 the rectification section in this part
00:04:45.740 00:04:45.750 of the tower the concentration of
00:04:47.450 00:04:47.460 lighter components increases the section
00:04:51.020 00:04:51.030 of the tower below the flash zone is
00:04:52.700 00:04:52.710 called the stripping section in this
00:04:55.339 00:04:55.349 section the lighter components are
00:04:57.230 00:04:57.240 vaporized or stripped from the heavier
00:04:59.270 00:04:59.280 liquid if a distillation tower worked
00:05:02.360 00:05:02.370 perfectly it would produce pure products
00:05:05.379 00:05:05.389 unfortunately that's not the case
00:05:07.159 00:05:07.169 the lighter products usually contain
00:05:09.439 00:05:09.449 some heavier fractions and the heavier
00:05:11.540 00:05:11.550 products usually contain some lighter
00:05:13.070 00:05:13.080 fractions this is sometimes referred to
00:05:15.529 00:05:15.539 as overlap distillation systems use
00:05:19.550 00:05:19.560 several methods to help maximize the
00:05:21.469 00:05:21.479 purity of the products one of these
00:05:23.839 00:05:23.849 methods is called refluxing the vapors
00:05:27.200 00:05:27.210 coming off the top of the tower are
00:05:28.879 00:05:28.889 condensed in a condenser and then
00:05:30.890 00:05:30.900 collected in a receiver part of the
00:05:33.469 00:05:33.479 liquid from the receiver is sent to
00:05:35.300 00:05:35.310 storage or to other units in the plant
00:05:37.310 00:05:37.320 as the towers overhead product the rest
00:05:40.520 00:05:40.530 of the liquid is pumped back into the
00:05:42.409 00:05:42.419 top of the tower the liquid that's
00:05:44.839 00:05:44.849 reintroduced into the tower is called
00:05:47.240 00:05:47.250 external reflux because it consists of
00:05:50.600 00:05:50.610 liquid that was cooled in the condenser
00:05:52.339 00:05:52.349 the external reflux is cooler than the
00:05:55.129 00:05:55.139 liquid in the top of the tower as the
00:05:57.499 00:05:57.509 external reflux cools the top of the
00:05:59.270 00:05:59.280 tower vapors made of heavier fractions
00:06:01.670 00:06:01.680 condensed liquid made of heavier
00:06:04.040 00:06:04.050 fractions flows down the tower and is
00:06:06.529 00:06:06.539 referred to as internal reflux meanwhile
00:06:09.830 00:06:09.840 the top of the tower is still hot enough
00:06:11.810 00:06:11.820 to keep the lighter fractions in vapor
00:06:14.029 00:06:14.039 form the vapors are drawn off the top of
00:06:16.820 00:06:16.830 the tower and into the condenser
00:06:19.689 00:06:19.699 refluxing increases the purity of the
00:06:22.159 00:06:22.169 overhead product because condensing the
00:06:24.439 00:06:24.449 vapors made of heavier fractions keeps
00:06:26.719 00:06:26.729 them out of the stream of vapors that
00:06:28.249 00:06:28.259 leaves the top of the tower another
00:06:31.399 00:06:31.409 method used to maximize product purity
00:06:33.529 00:06:33.539 is called reboiler the bottoms liquid
00:06:37.100 00:06:37.110 that's drawn off from the tower is sent
00:06:39.050 00:06:39.060 to a heater called a reboiler
00:06:40.989 00:06:40.999 the rest of the bottoms liquid is sent
00:06:43.239 00:06:43.249 to storage or to other units in the
00:06:44.949 00:06:44.959 plant as the towers bottoms product the
00:06:48.429 00:06:48.439 reboiler heats the liquid it receives so
00:06:50.829 00:06:50.839 that a mixture of vapors and liquid is
00:06:52.509 00:06:52.519 formed depending on the system either
00:06:55.359 00:06:55.369 vapors or the mixture of vapors and
00:06:57.399 00:06:57.409 liquid is then reintroduced into the
00:06:59.439 00:06:59.449 tower the hot vapors cause any lighter
00:07:02.529 00:07:02.539 fractions in the liquid at the bottom to
00:07:04.719 00:07:04.729 vaporize and move up the tower this
00:07:07.569 00:07:07.579 reduces the amount of lighter fractions
00:07:09.609 00:07:09.619 in the bottoms product the reboiler
00:07:12.699 00:07:12.709 provides the major portion of the heat
00:07:14.739 00:07:14.749 that's required to make the distillation
00:07:16.119 00:07:16.129 process work in the type of system we've
00:07:19.419 00:07:19.429 been discussing the heat supplied by
00:07:21.489 00:07:21.499 preheating the feed is not sufficient
00:07:24.039 00:07:24.049 for proper distillation the reboiler is
00:07:26.889 00:07:26.899 needed to provide enough additional heat
00:07:28.749 00:07:28.759 to vaporize the lighter fractions in the
00:07:30.969 00:07:30.979 tower so that the products meet
00:07:32.709 00:07:32.719 specifications although all distillation
00:07:35.649 00:07:35.659 towers serve the same basic function
00:07:37.749 00:07:37.759 they don't all have the same internal
00:07:39.429 00:07:39.439 components one type of tower uses trays
00:07:42.850 00:07:42.860 called sieve trays to separate vapors in
00:07:45.129 00:07:45.139 liquid that type of Tower is covered in
00:07:47.649 00:07:47.659 the tower operation part of this program
00:07:49.629 00:07:49.639 in this part will look inside to other
00:07:53.079 00:07:53.089 types of distillation towers and see how
00:07:55.449 00:07:55.459 their internal components differ let's
00:07:58.839 00:07:58.849 start with a tower that uses trays with
00:08:00.729 00:08:00.739 bubble caps the holes in each tray are
00:08:04.119 00:08:04.129 covered with caps called bubble caps the
00:08:07.209 00:08:07.219 slots in these bubble caps disperse the
00:08:09.399 00:08:09.409 rising vapors through the liquid on the
00:08:11.229 00:08:11.239 tray each bubble cap has many slots and
00:08:14.919 00:08:14.929 each tray has many bubble caps to spread
00:08:17.199 00:08:17.209 out the vapors this ensures a maximum
00:08:19.989 00:08:19.999 contact between vapors and liquid so
00:08:22.359 00:08:22.369 that maximum heat transfer can take
00:08:23.919 00:08:23.929 place
00:08:25.589 00:08:25.599 another type of tower called a packed
00:08:28.269 00:08:28.279 tower contains layers of devices called
00:08:30.789 00:08:30.799 packing instead of trays with bubble
00:08:32.829 00:08:32.839 caps there are many different types of
00:08:35.649 00:08:35.659 packing some towers have sections that
00:08:38.799 00:08:38.809 are filled with cylindrical rings like
00:08:40.600 00:08:40.610 the one Illustrated here it's known as a
00:08:42.939 00:08:42.949 rash agreeing another type of packing is
00:08:45.939 00:08:45.949 known as a burl saddle the packing
00:08:49.150 00:08:49.160 breaks up the liquid so that it flows
00:08:50.740 00:08:50.750 over a large amount of surface area this
00:08:53.379 00:08:53.389 exposes more of the
00:08:54.670 00:08:54.680 liquid to the vapors and increases heat
00:08:56.860 00:08:56.870 transfer from the vapors to the liquid
00:08:59.370 00:08:59.380 packing can be made for many different
00:09:01.480 00:09:01.490 materials including porcelain copper
00:09:03.910 00:09:03.920 aluminum and iron the main requirement
00:09:07.150 00:09:07.160 is that the material must be compatible
00:09:09.070 00:09:09.080 with the liquid in the tower and the
00:09:11.139 00:09:11.149 conditions under which the tower is
00:09:12.579 00:09:12.589 operated this is a section of another
00:09:15.579 00:09:15.589 type of packing from a distillation
00:09:17.199 00:09:17.209 tower it's called a packing grid each
00:09:20.980 00:09:20.990 layer in the grid has spaces for vapors
00:09:23.290 00:09:23.300 to rise through the packing on their way
00:09:24.970 00:09:24.980 up the tower liquid flows over these
00:09:27.639 00:09:27.649 surfaces which channel the liquid as it
00:09:29.860 00:09:29.870 flows down the tower the packing grid
00:09:32.440 00:09:32.450 provides a great deal of surface area
00:09:34.300 00:09:34.310 where contact between the vapors and the
00:09:36.100 00:09:36.110 liquid can take place so heat transfer
00:09:38.680 00:09:38.690 is maximized temperature control is
00:09:41.260 00:09:41.270 crucial to the operation of a
00:09:42.699 00:09:42.709 distillation system correct temperatures
00:09:45.070 00:09:45.080 are necessary to vaporize the lighter
00:09:47.050 00:09:47.060 components of a liquid mixture while
00:09:49.180 00:09:49.190 keeping the heavier components in the
00:09:50.710 00:09:50.720 vapors to a minimum if the temperatures
00:09:53.470 00:09:53.480 at certain points in the system are
00:09:55.180 00:09:55.190 either too high or too low
00:09:57.120 00:09:57.130 acceptable products won't be produced
00:09:59.579 00:09:59.589 let's go over several points in the
00:10:01.930 00:10:01.940 distillation system where temperature is
00:10:03.820 00:10:03.830 monitored as we do keep in mind that the
00:10:06.850 00:10:06.860 mixture will be referring to is a binary
00:10:09.040 00:10:09.050 liquid mixture that is a mixture that
00:10:11.410 00:10:11.420 has two components we'll begin with the
00:10:14.410 00:10:14.420 temperature at the top of the tower the
00:10:16.840 00:10:16.850 temperature at the top of the tower
00:10:18.070 00:10:18.080 should be at or slightly above the
00:10:20.140 00:10:20.150 boiling temperature of the desired
00:10:21.970 00:10:21.980 overhead product at the operating
00:10:23.949 00:10:23.959 pressure of the tower if the temperature
00:10:26.620 00:10:26.630 at the top of the tower is higher than
00:10:28.240 00:10:28.250 it should be more of the heavier
00:10:30.220 00:10:30.230 components will vaporize and become part
00:10:32.650 00:10:32.660 of the overhead product instead of
00:10:34.690 00:10:34.700 flowing down the tower as a liquid on
00:10:36.390 00:10:36.400 the other hand if the temperature at the
00:10:39.220 00:10:39.230 top of the tower is lower than it should
00:10:41.350 00:10:41.360 be less of the lighter components will
00:10:43.720 00:10:43.730 vaporize some of the lighter components
00:10:46.269 00:10:46.279 will remain as a liquid and flow down
00:10:48.100 00:10:48.110 the tower the temperature at the bottom
00:10:51.010 00:10:51.020 of the tower is also important the
00:10:53.710 00:10:53.720 temperature at the bottom of the tower
00:10:55.150 00:10:55.160 is usually slightly below the boiling
00:10:57.130 00:10:57.140 point of the heavier component if the
00:10:59.260 00:10:59.270 00:11:00.610 00:11:00.620 is too high more of the heavier
00:11:02.860 00:11:02.870 components will vaporize and move up the
00:11:04.750 00:11:04.760 tower instead of remaining as a liquid
00:11:06.940 00:11:06.950 if
00:11:08.199 00:11:08.209 the temperature at the bottom of the
00:11:09.429 00:11:09.439 tower is too low less of the lighter
00:11:11.829 00:11:11.839 00:11:13.660 00:11:13.670 tower another place where temperature
00:11:16.809 00:11:16.819 control is important is at the feed
00:11:18.819 00:11:18.829 point the temperature at the feed point
00:11:21.189 00:11:21.199 should be within the boiling range of
00:11:22.900 00:11:22.910 the mixture the temperature at the feed
00:11:25.090 00:11:25.100 point should be close to the temperature
00:11:27.009 00:11:27.019 of the feed tray the temperature of the
00:11:29.319 00:11:29.329 feed tray depends on its physical
00:11:31.090 00:11:31.100 location in the tower for example the
00:11:34.059 00:11:34.069 lower the feed tray is in the tower the
00:11:36.340 00:11:36.350 higher its temperature will be if the
00:11:38.949 00:11:38.959 temperature at the feed point is higher
00:11:40.509 00:11:40.519 than it should be more of the heavier
00:11:42.579 00:11:42.589 00:11:44.919 00:11:44.929 tower instead of moving down the tower
00:11:46.960 00:11:46.970 as a liquid on the other hand if the
00:11:49.869 00:11:49.879 feed point temperature is too low less
00:11:52.629 00:11:52.639 of the lighter components will vaporize
00:11:54.009 00:11:54.019 and more lighter components will end up
00:11:57.129 00:11:57.139 in the bottom of the tower while the
00:11:59.769 00:11:59.779 temperatures at various points in a
00:12:01.419 00:12:01.429 distillation system are important the
00:12:03.759 00:12:03.769 relationships between the temperatures
00:12:05.679 00:12:05.689 are also important the temperature
00:12:07.989 00:12:07.999 decreases is the material moves higher
00:12:09.970 00:12:09.980 in the tower the gradual decrease in
00:12:12.429 00:12:12.439 temperature from the bottom of a
00:12:13.809 00:12:13.819 distillation tower to the top is called
00:12:16.059 00:12:16.069 the temperature gradient the temperature
00:12:18.999 00:12:19.009 gradient is measured in terms of the
00:12:20.889 00:12:20.899 difference between the temperature at
00:12:22.419 00:12:22.429 the bottom of the tower and the
00:12:24.160 00:12:24.170 temperature at the top of the tower in
00:12:27.669 00:12:27.679 order to maintain the proper temperature
00:12:29.470 00:12:29.480 gradient temperatures at critical points
00:12:31.660 00:12:31.670 in the system must be controlled
00:12:33.509 00:12:33.519 temperatures in a distillation system
00:12:35.439 00:12:35.449 are typically controlled in three ways
00:12:38.400 00:12:38.410 one way is to control the temperature of
00:12:41.049 00:12:41.059 the feed mixture by using a pre heater
00:12:43.090 00:12:43.100 this regulates the temperature at the
00:12:45.369 00:12:45.379 feed point at the bottom of the tower
00:12:47.949 00:12:47.959 temperature is controlled by the amount
00:12:49.720 00:12:49.730 of heat that is added by the reboiler
00:12:51.660 00:12:51.670 this added heat is referred to as boil
00:12:54.519 00:12:54.529 up the temperature at the top of the
00:12:57.639 00:12:57.649 tower is controlled by the amount or the
00:12:59.559 00:12:59.569 temperature of the cool liquid that's
00:13:01.569 00:13:01.579 pumped back into the tower from the
00:13:03.309 00:13:03.319 overhead receiver this is called the
00:13:05.829 00:13:05.839 reflux rate increasing the reflux rate
00:13:08.999 00:13:09.009 decreases the temperature at the top of
00:13:11.109 00:13:11.119 the tower some distillation systems
00:13:14.439 00:13:14.449 contain equipment known as pump arounds
00:13:16.449 00:13:16.459 the purpose of a pump around is to
00:13:18.909 00:13:18.919 remove hot liquid from the tower and
00:13:20.650 00:13:20.660 palm
00:13:21.250 00:13:21.260 through a cooler the cooled liquid is
00:13:23.650 00:13:23.660 then reintroduced at a higher level in
00:13:26.080 00:13:26.090 the tower a pump around helps control
00:13:28.510 00:13:28.520 the temperature of the internal reflux
00:13:30.160 00:13:30.170 since pressure affects the boiling
00:13:32.350 00:13:32.360 temperature of a liquid it's an
00:13:34.060 00:13:34.070 important factor in the distillation
00:13:35.590 00:13:35.600 process if precious in a distillation
00:13:38.470 00:13:38.480 system are not correct product purity
00:13:40.810 00:13:40.820 could decrease tower pressure is often
00:13:44.200 00:13:44.210 controlled by a pressure control valve
00:13:46.120 00:13:46.130 located on the overhead receiver this
00:13:49.270 00:13:49.280 valve controls pressure by releasing
00:13:51.370 00:13:51.380 vapours and any non condensable gases
00:13:53.560 00:13:53.570 that have collected in the receiver in
00:13:55.620 00:13:55.630 some cases a vacuum system draws gases
00:13:59.170 00:13:59.180 from the receiver to control tower
00:14:00.670 00:14:00.680 pressure another pressure that's
00:14:03.490 00:14:03.500 important to an operator is the towers
00:14:05.590 00:14:05.600 differential pressure the towers
00:14:08.140 00:14:08.150 differential pressure is the difference
00:14:10.090 00:14:10.100 between the pressure at the bottom of
00:14:11.680 00:14:11.690 the tower and the pressure at the top of
00:14:13.750 00:14:13.760 the tower this difference in pressure is
00:14:16.480 00:14:16.490 caused by the flow of vapors in the
00:14:18.460 00:14:18.470 tower without vapor flow there is no
00:14:21.670 00:14:21.680 differential pressure generally if the
00:14:24.970 00:14:24.980 rate at which the vapors move up the
00:14:26.500 00:14:26.510 tower decreases the differential
00:14:28.900 00:14:28.910 pressure will also decrease and if the
00:14:31.900 00:14:31.910 00:14:33.280 00:14:33.290 tower increases the differential
00:14:35.590 00:14:35.600 pressure will increase changes in the
00:14:39.040 00:14:39.050 differential pressure may indicate that
00:14:40.660 00:14:40.670 a problem exists for example an increase
00:14:43.690 00:14:43.700 in differential pressure could be an
00:14:45.430 00:14:45.440 indication that the feed rate is too
00:14:47.380 00:14:47.390 high too much feed entering the tower
00:14:49.690 00:14:49.700 will overload it if this happens the
00:14:52.450 00:14:52.460 differential pressure will increase and
00:14:54.280 00:14:54.290 the tower will be unable to make the
00:14:56.110 00:14:56.120 desired separation in this case it might
00:14:59.020 00:14:59.030 be necessary to decrease the feed rate
00:15:01.470 00:15:01.480 now changes in the towers differential
00:15:04.240 00:15:04.250 pressure may be caused by other problems
00:15:06.490 00:15:06.500 for example if the differential pressure
00:15:09.000 00:15:09.010 increases the boil up rate may be too
00:15:11.770 00:15:11.780 high in other words the reboiler may be
00:15:14.590 00:15:14.600 returning too much vapor or vapor liquid
00:15:16.840 00:15:16.850 mixture to the tower this problem can be
00:15:19.930 00:15:19.940 corrected by reducing the boil up rate
00:15:22.620 00:15:22.630 another problem that may affect the
00:15:24.790 00:15:24.800 towers differential pressure is a
00:15:26.290 00:15:26.300 decrease in condenser efficiency if the
00:15:29.440 00:15:29.450 condensers tubes are plugged or there's
00:15:31.570 00:15:31.580 not enough cooling water flowing through
00:15:33.010 00:15:33.020 the condenser the
00:15:34.500 00:15:34.510 pressure will increase as a result the
00:15:37.860 00:15:37.870 flow of vapors from the tower to the
00:15:39.420 00:15:39.430 condenser will decrease and so will the
00:15:42.090 00:15:42.100 vapor flow up the tower this means that
00:15:44.760 00:15:44.770 the tower top pressure will increase and
00:15:46.950 00:15:46.960 the differential pressure will decrease
00:15:48.900 00:15:48.910 if a condenser problem is suspected the
00:15:52.560 00:15:52.570 condenser should be checked and
00:15:54.060 00:15:54.070 corrective actions should be taken if
00:15:55.980 00:15:55.990 necessary now changes in the towers
00:15:59.460 00:15:59.470 differential pressure may have other
00:16:01.050 00:16:01.060 causes in addition to the ones we've
00:16:02.610 00:16:02.620 identified so it's important to
00:16:04.860 00:16:04.870 carefully evaluate any situation before
00:16:07.290 00:16:07.300 corrective action is taken one of these
00:16:09.570 00:16:09.580 00:16:12.930 00:16:12.940 00:16:14.550 00:16:14.560 00:16:16.590 00:16:16.600 00:16:19.200 00:16:19.210 00:16:21.030 00:16:21.040 00:16:23.040 00:16:23.050 00:16:26.250 00:16:26.260 00:16:28.140 00:16:28.150 00:16:30.570 00:16:30.580 00:16:32.970 00:16:32.980 00:16:36.330 00:16:36.340 00:16:38.040 00:16:38.050 00:16:40.860 00:16:40.870 liquid in the top of in this topic we
00:16:43.500 00:16:43.510 looked at two key factors in the
00:16:45.090 00:16:45.100 distillation process temperature and
00:16:47.220 00:16:47.230 pressure remember that although we
00:16:49.950 00:16:49.960 discussed them separately temperature
00:16:51.960 00:16:51.970 and pressure work together both of these
00:16:54.360 00:16:54.370 factors must be correct for the
00:16:55.920 00:16:55.930 distillation process to work properly
00:16:57.950 00:16:57.960 now try to answer some practice
00:17:00.510 00:17:00.520 questions to check your understanding of
00:17:02.730 00:17:02.740 what we've gone over

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