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[MUSIC] >> Narrator: Welcome to the Energy Assessment
module, the second in our series on Air Toxics Standards for Area Source Boilers.
The goal of an energy assessment is to identify energy saving opportunities within a boiler
and the processes that it supports. Please note that the energy savings opportunities
are not required to be implemented. If you have an existing oil, biomass or coal-fired
unit with a heat input capacity of 10 MM Btus per hour or greater, you are subject to the
one-time Energy Assessment rule requirement. New and limited use boilers are excluded as
are facilities that operate under an energy management program compatible with ISO 50001
where effected units are included. As a reminder, the compliance date for this
requirement is March 21, 2014. Your energy assessment must be performed by
a qualified energy assessor. This person or company should have the background, experience
and expertise to evaluate energy savings opportunities for the types of boilers or energy use systems
located at your facility. The energy assessor may be either a company
employee or an outside specialist. For more complicated boiler or energy use systems or
facilities with multiple boilers, a group such as a consulting firm or a company's engineering
staff could perform the required assessment. To help you in selecting a qualified assessor,
EPA has defined a list of skill-sets and capabilities that the person conducting the assessment
will need to possess. This list can be accessed through EPA's website at the address on your
screen. So where does one find a qualified energy
assessor? We sat down with Dr. Herb Eckerlin from the Department of Mechanical & Aerospace
Engineering of North Carolina State University and asked.
>> DR. HERB ECKLERLIN: What I would recommend that people ask the perspective assessor for
a resume, education and experience. That would be the
first thing I'd do. Secondly I'd ask all for a listing of the facilities that he or she
has assessed and also a list of contact people and contact numbers that you would have and
then thirdly, some sample reports. With that kind of information I think you're able to
make a reasonable judgment and then of course talking
to other folks is quite helpful. That's what I would recommend.
>> NARRATOR: Once you have secured the services of an energy assessor, you might be asked
to provide facility information in advance of their site visit.
>> DR. HERB ECKERLIN: Typically the information that I would ask for, that I would recommend
that is to be filled out is boiler operational information in others words, the type of boiler,
when it was built, the make, the capacity, be a boiler horsepower or pounds of steam,
fire tube or water tube, pressure, operating pressure, feed water temperature, perhaps
heat recovery if there's an economizer involved or not, stack temperature. Just general boiler
operation. And this gives the person some preliminary information before he gets. He
knows what to expect and it makes the whole situation much more effective.
Also as I've indicated in my forms the two forms I have one is for the boilers and one
is for the boiler house. In other words the boiler house information would involve things
like deaerators, condensate return tanks, heat recover. That may not be covered on the
boiler form.
>> NARRATOR: The energy assessor then schedules a meeting and walk-through of the facility.
The complete assessment could take anywhere from a few hours to a day depending on the
number of boilers and size of the facility. Here is what a typical energy assessment might
look like. The seven items that must be included as part of your assessment are identified.
The assessor first reviews the completed information forms with the Boiler Plant Superintendent
to ensure accuracy. >> DR. HERB ECKLERLIN: The information you've
completed here indicates that the operating pressure's about 120 pounds?
>> PAUL REYNOLDS: That is correct. >> ECKERLIN: Right. Feed water temperature's
233? >> REYNOLDS: Yes.
>> ECKERLIN: : From the deaerator? For oil atomization you're using compressed air on
the smaller boilers? >> REYNOLDS: Yes.
>> ECKLERLIN: And steam atomization on the big one?
>> REYNOLDS: That is correct. >> ECKERLIN: All of these boilers are pressurized
boilers which means that there's just an FD fan
no ID fan? >> REYNOLDS: That is correct.
ECKLERIN: The small boilers, the fire tube boilers do not have any heat trap like an
economizer? >> REYNOLDS. No.
ECKLERLIN: But the large boiler does. >> REYNOLDS: That is correct.
>> ECKERLIN: Stack temperature is measured? >> REYNOLDS: Yes.
>> ECKERLIN: From a previous test I notice the temperature was perhaps on one of the
boilers was may be five hundred degrees which is a bit high, you know that?
>> REYNOLDS: Yes. >> ECKERLIN: We, ah, that suggests to us perhaps
that there may be a heat transfer problem possibly scale
or possibly soot buildup on the tubes themselves. So that's something we probably have to look
at in the future. >> NARRATOR [Voice Over]: After discussing
general boiler information the assessor reviews plant
and auxiliary equipment, engineering plans and drawings and evaluates fuel usage logs.
>> ECKERLIN: Do you wanna just quickly summarize what you have here?
>> REYNOLDS: Well this is just a layout of part of our distribution coming out of this
plant. We're generating the steam that goes to these
different buildings and then from those buildings we have the return of the condensate coming
back from those buildings. And the amount of condensate that we're getting back, we're
looking at how much condensate are we getting back at the producer end and if we're not
getting the returns that we're looking for, we can start pulling down to the building
to figure out which building's are not returning so we can kinda zero in on where the opportunities
are at. >> ECKERLIN: Right. Well condensate is so
important because if you lose half of your condensate, you're losing six percent efficiency
of your boiler steam system so that's critical. Also I'm glad you're paying such attention
to it because condensate represents not only water but it represents a lot of heat coming
back. If we go out to the plant later we'll look at the condensate return tank, the surge
tank as you call it, and see what that temperature is. I believe it
was perhaps 160 so you have 160 coming back and that's probably almost a hundred degrees
higher than the make-up water coming in so that's an energy savings and then an another
thing that people often forget is that condensate is chemically-laden water so it's already
been treated it's gonna save you in chemical costs and finally, it reduces more condensate
reduces make-up water so you save on the water bill, the energy bill and the chemical bill
all at once. So that's great. That's wonderful. Another
thing that people are concerned about is the startup and shutdown procedures on your boilers.
You know thermal stresses are a big part of rapid big problem with rapid start-up. What
is your, specifically your step-by-step process on startup and then shut down as you shift
from one boiler to the next? >> REYNOLDS: Our startup and shutdown is more
specific to the equipment that's in those buildings.
This one has the Cleaver Brooks fire-tube boilers in them.
>> ECKERLIN: Right. >> REYNOLDS: So we, it is a single burner.
We start a boiler at low fire and allow it to idle to allow
that expansion to start going through there. Allow it to build up the pressure within the
vessel before it would create enough steam pressure
to open the non-return. While we have another boiler
online generating the steam. Then we would slowly start increasing they firing rate on
the boiler we're bringing on the boiler that you would be taking off would respond by backing
off so we are starting to decrease the amount of fuel we're putting
in one as we're increasing the other one and trying to make the transition that a way.
So that kinda answers both questions at the same time. But uh. That that makes the entire
system more stable. >> ECKERLIN: Right.
>> REYNOLDS: We're not bringing something up quick, we're not thermal shocking it. We're
not changing our water load going through the
planet. We're trying to make it where it's just a transition.
>> ECKERLIN: Yeah. And that will extend the life of the boilers too.
>> REYNOLDS: Yes. >> ECKERLIN: Because you're not stressing
them so hard. >> REYNOLDS: And we're not stressing the refractory
and the things like that. >> ECKERLIN: Right
>> REYNOLDS: for our passes and the >> ECKERLIN: Right. Right, right. Well that's
and I guess for these fire tube boilers the start-up period would be about two hours?
>> REYNOLDS: Correct. Usually they'll warm up in about two hours to the point that we
start making them take on the load. We also usually
maintain one with a steam drum in the mud drum heater.
>> ECKERLIN: Oh okay that's good. >> REYNOLDS: By doing that, we're helping
maintain the chemistry within that piece of equipment
and it gives those a running start trying to bring one on. Because it's already at fifty
pounds of pressure before we actually put the fire.
>> ECKERLIN: And so that's a good deal of heat in there. . .
>> REYNOLDS: Yes. >> ECKERLIN: . . . there already. You know
as well as I do that stack loss is one of the big losses we have
in operating a boiler and something we have to be very cognizant of and sensitive to.
And the two big variables there are stack temperature and 02. The oxygen level in the
flue gas. Also one thing that we haven't talked about is when you have an increase in stack
temperature there is the possibility that the baffle in the back end of the boiler could
break out or have a hole in it then those flue gases go from the first pass to the fourth
pass and skip the two intermediate ones and so if you have a sudden increase in stack
temperature it could be a baffle problem which is something people have to be aware of.
And so there's some opportunities there I think that we have to look at also . . . [fade
down] >> NARRATOR [Voice Over]: A visual inspection
of the boiler and related equipment is then conducted.
>> ECKERLIN: Paul, in the typical Energy Assessment, one of the first things we want to do is to
evaluate the boiler house. By that I mean, how clean
is it, how well kept it is. That tells us a great deal about what we're dealing with,
what to expect. Now in a visual inspection we really want to focus on
three-year areas. One would be the steam pressure, we'll talk about that in a moment. The other
is the water level and thirdly the fuel. So let's look at the steam pressure first. Up
here, you see on the left hand side, you see a pressure controller. That boiler here is
controlled by steam pressure. As the pressure drops
the fuel will increase, as the pressure goes too high, the fuel will decrease. So that's
very important. These typical industrial boilers are pressure
controlled. The second controller up there has to do with a high pressure cut-off. In
other words, this boiler is operating at 120 pounds. If it goes to
130 or 135, we want that fuel to cut off. You don't want this thing to explode, okay?
So that's important. Those are the two functions there of that
steam pressure controller. One is the control itself one is the high
pressure safety. The second thing we want to focus on is water level.
That's very, very important. Up here, you see the water level in that glass tube.
That boiler has to maintain a certain water level; if that water level drops, you're gonna
burn up this boiler. That's not good. Okay? And if the water level goes too high, the
feedwater pump that controls cuts off. This is one part of the controller. If this control
does not work, we have an auxiliary water level control on the other side. So we have
a backup. That tells you how important water level is to the operation of this
fire tube boiler. You have a water tube boiler there's also a water level control on the
drum. So for a water tube boiler, fire tube the same principles apply. The third thing
I want focus on is fuel flow. Here we have the controller and we're measuring
the fuel oil flow on a continuous basis. That's very important. We measure this every day.
That tells us how much oil we're burning on a gallon basis every day.
It enables us to find out how effectively this boiler is running. I notice here this
is the bottom blow down valve for the front and you have another one in the back. Could
you just tell us the procedure you use when you do the bottom blow down procedure because
a lot of times people keep that valve open an awful long time and all they're doing is
dumping out water and we would like to avoid that if possible.
>> REYNOLDS: Yes. Well again, what we're trying to do is minimize the amount of water that
we're blowing down but yet, get a good blow down. First thing that we do is we open the
valve then we take your isolation valve and slowly warm up the line. Then we close the
valve, fully open your isolation valve. Then we take that valve and we open it for two
to three seconds. And then close it back. That allows whatever was there, a quick vortex
to pull that out. >> ECKERLIN: All that said sediment.
>> REYNOLDS: Sediment. We close it and whatever we've stirred up, give it a second or two
to settle down, give it another quick blow and close it. We usually do that twice on
each end. We do, we're on a 12-hour shift, so we're doing it at the first of each shift
so this gets blown down twice a day. >> ECKERLIN: Both ends?
>> REYNOLDS: Both ends. >> ECKERLIN: Okay that's good. That's a good
procedure. Can you review for us now the all adjustment of the air and the fuel? I think
you set up the air first and you do this I believe at low medium and high fire?
>> REYNOLDS: That is correct. >> ECKERLIN: And you start at low fire?
>> REYNOLDS: Yes. And we set the air first and then tune your fuel to the air.
>> ECKERLIN: At a particular load? >> REYNOLDS: At a particular load. We have
the ability to vent steam through a muffler. So we can take a boiler with no load on it,
just idling and make that set point. We can adjust it up to 25 percent, tune there.
Then go on up to 50 percent, 75 percent, full load. Then we track it back down and go back
through it again. So then we have the ability to be getting
the curve set for our fuel from low, 25 percent, 50 percent, 75 percent, and adjust it all
the way through the curve. >> ECKERLIN: Now you do that by adjusting
the cam? >> REYNOLDS: We do that by adjusting the cam.
>> ECKERLIN: On the fuel? >> REYNOLDS: On the fuel.
>> ECKERLIN: Ah that's good. >> REYNOLDS: So here's the temperature gage
and this is where as they're making their rounds they are able to record that. And they're
also recording their steam load and everything as they're doing it. So we can capture that
data, if there's a sudden change in it, we know that something's happened within the
boiler. Or if we need to look at, a temperature may be normal for what that load is we can
start comparing that temperature at that load at a different time. Would you like to look
at the flame pattern? >> ECKERLIN: Yes, let's do that.
Well a picture's worth a thousand words isn't it?
>> REYNOLDS: It is. >> ECKERLIN: It's beautiful. Very well done.
Well Paul I think we're here by the condensate tank or the surge tank as you call it. This
is where the condensate comes back from all of the facilities. That's sort of the liquid
gold because it's got energy, it's got chemicals in it, and it's water which doesn't have to
be made up. What's the temperature of the condensate tank here now?
>> REYNOLDS: Well it's around 150 to 160. That is a combination of the condensate that
is being returned plus that amount of soft water that we've added to it as make-up. So
this is our average temperature of the condensate and the make-up.
>> ECKERLIN: So actually then the condensate coming back is going to be higher than that.
>> REYNOLDS: Correct. Which is very good. >> ECKERLIN: Yeah. Also I notice here in this
facility that you have the piping which is color coded.
>> REYNOLDS: That is correct. >> ECKERLIN: You have the green which is the
condensate return. The yellow there is the make-up water. Then the steam, I guess that's
for some heating here? >> REYNOLDS: The heating here and then where
we're taking it out to the distribution. But the color coding makes it much easier to trace
down lines. Otherwise you'd just be seeing a lot of pipes up in the ceiling and it's
easy to get them crossed up. The color-coding is a great, great help.
>> ECKERLIN: That's something that you don't see. I don't see very often as you go around
the country so that's a real plus here. And then behind here, you have the condensate
tank, uh pumps. Which pumps the water to the deareator. Which is up, we'll see that later.
Are these variable speed pumps? >> REYNOLDS: Yes they are. So we're only using
the amount of energy necessary to achieve what we're trying to do. Which is take a volume
of water from here up to the next level. As we start making more steam, the deareator
will be using more water so this putting more water in the deareator so our equipment adjusts
according to whatever our load is. >> ECKERLIN: Are you adding any steam to this
tank at all here? >> REYNOLDS: No. All the steam is added at
the deaerator. >> ECKERLIN: Paul, we have here this continuous
condensate, not condensate, blow down heat recovery. Could you pass us through that please?
>> REYNOLDS: Well to maintain the chemistry in the boiler you have a continuous blow down
to maintain those solids. Of course that is boiler water that has all the heat in it.
So that water is piped to go through this heating exchanger. That's going through one
side and on the other side of this heat exchanger we have the make-up water that would be going
into our surge tank. So we are literally transferring the heat or part of that heat of what would
be being blown down to the drain and pre-heating the water that goes to our condensate receiver.
So we're capturing the heat instead of losing it.
>> ECKERLIN: That's a good energy conservation measure that people ought to consider all
of the time. >> REYNOLDS: Very good. Now we'll go up to
the deaerator where this is going. >> ECKERLIN: Well Paul here we are at the
deareator. This is the device that removes mechanically the oxygen from the feedwater.
>> REYNOLDS: Correct. >> ECKERLIN: Ah, typically this is at low
pressure. What is the pressure of this vessel here now?
>> REYNOLDS: Were probably eight to 10 pounds. >> ECKERLIN: Eight to ten pounds, and what
is the water temperature, the feedwater temperature? >> REYNOLDS: We're approaching 230.
>> ECKERLIN: Approaching 230 degrees. That's sort of what it shows here. That's great.
Ah, one of the problems people will often have with deaerators is they don't operate
at the proper pressure or the temperature. Sometimes they're below 212 and then it doesn't
really serve their purpose at all so it's good that you're up and above that 8 to 10
pounds, 230 so that indicates good operation in this particular instance. This is the storage
section here? >> REYNOLDS: Correct.
>> ECKERLIN: We're going around the corner now and we're going to look at the mechanical
section above it, is that correct? >> REYNOLDS: That is correct. The way that
we maintain the temperature is through a PRV valve. And that is feeding the mechanical
section of the deareator. As the load goes up the water would increase
going into it. You would have a pressure drop in
the PRV valve would open up and apply more steam. As the load goes down, there'd be less
water the PRV valve would close so that way we maintain a constant pressure
on the mechanical side of the deareator and the result is the storage tank
water is at a constant level around 230. From that storage tank,
it then goes to our feedwater pump that are located in the basement. They're located there
to where the head pressure going into the suction side
of the pump is maintained to keep that hot water from flashing in the pump.
And from there we can boost the water pressure back up to where we can put it into our boiler.
>> ECKERLIN: Roughly at 230 feedwater temperature. >> REYNOLDS: Water temperature entering the
boiler. >> ECKERLIN: That's a good description and
an important part of a boiler operation and mechanical removal of oxygen from the feed
water and it avoids the use of chemicals so that's so important.
This is a system where you take bottom blow down, not continuous, bottom blow down and
you have to prepare it so it's acceptable to the city. So you have to cool it. And this
is the cold water coming in. Can you explain then to the folks what's happening here?
>> REYNOLDS: The first step is to minimize how much bottom blow down you have. So by
minimizing that and having it where it's in shorter parts, that reduces how much water
weíre sending down the drain. >> ECKERLIN: That goes back to the 3 seconds
you were talking about? >> REYNOLDS: Correct. And it's also less water
that we're having to make up for what we're blowing down. So that water comes into this
accumulator tank and as it passes through, the automatic valve will open to cool that
water down for what was entering into their sewer system. So the first step is to minimize
how much blow down we have and then to minimize how much cooling water we're using to reach
the set point. So we'll do it to where it kinda dominoes up and dominoes down. We try
to minimize what we're doing to get the proper effect out of it and balance our water temperature.
>> ECKERLIN: The important thing for people to recognize is that this water here for cooling
is only for cooling so it's costing the university money to do that. So it's important to communicate that to the folks upstairs.
>> REYNOLDS: Right. >> ECKERLIN: Thank you.
>> NARRATOR: During the plant walk-through the assessor identifies a number of potential
measures that might improve energy efficiency of the facility. He then summarizes findings
for the plant supervisor. >> ECKERLIN: Well Paul, thank you so much
for a very interesting tour, very comprehensive tour. I just want to summarize my comments
with a few recommendations. Perhaps the first one would be in the area of stack temperature,
flue gas temperature, leaving the last point of heat recovery. That probably can be reduced.
Some other things you may want to look at would be soot on the flue gas side or scale
on the water side. Another item that people often don't check
which is important are the baffles, the condition of the baffles at the back end of the boiler.
If they break, the flue gases then make a short circuit from pass 1 to pass four which
would cause the temperature of that flue gas which you're monitoring pretty well,
would cause it to jump rather dramatically. In that way you're checking things you'll
catch that. That's something to be aware of. the same
thing goes for oxygen in the flue gas. That's a measure of excess air and you need to keep
close tabs on that. If the oxygen gets too high uh you'll need a burner tune-up which
cost maybe a thousand to twelve hundred dollars. That's often a good investment. Another important
item here that we have to keep in mind is whenever we're talking about stack temperature
or 02, we always have to keep in mind that that varies with load okay very load dependent.
So if you're measuring 02 or stack temperature measure it in high fire, mid-range, and low
fire and see how that goes. And if you do this on a regular basis checking stack temperature
and O2 on a regular basis, do it the same load every time. That's important. Lots of
times people will say, 'hey the stack temperature's 450 today isn't that great?'
Okay well it may be at low fire and that may be the reason it's lower. So load is an important
factor in both stack temperature and O2. Also when we're doing a stack, a flue gas analysis,
pay attention to CO, the carbon monoxide. That's a measure of incomplete combustion.
CO is actually a fuel. It has a heating value of 43.47 BTU's per pound. It's not nearly
what it what other fuels are but it is a fuel. And so you want to eliminate, minimize that.
Typically a guideline is to keep CO below 200 parts per million that would
be acceptable, that's a rule of thumb. Condensate return. We've talked a lot about that. I think
you're doing a good job on that. As I mentioned earlier, if you lose 50 percent of your condensate
that's representing a 6-percent energy loss. Okay? In addition to that you have chemical
and water losses too. So that's an important variable in your overall operation. Bottom
blow-down. You seem to have that under control on three-second cycles, just keep up the good
work in that area. One area that I think you're probably aware of is that blow down cooler
down there in the corner in the basement. You'd like to minimize using city water to
cool hot blow down. So that's an area for improvement perhaps. Steam trap maintenance
by the other staff not necessarily your operation or your responsibility. But steam trap maintenance
is so important particularly in a large facility like this where we have traps throughout the
steam distribution line and in the buildings themselves so that's important. Cold end corrosion.
It's another thing to pay attention to particularly when you're firing heavy oil that may become
more of a problem later when boiler number 4 begins to play a larger role here. And cold
end corrosion but you're doing something about that by raising the feed water temperature
to the economizer. So that's positive. Just be sensitive to cold end corrosion because
of the importance and the effect it has. Particularly on economizers. I go around the country and
I see a lot of economizers. And most of them are out of
service simply because of cold end corrosion. So you want to avoid that. But overall I think
you've done a nice job here and I really appreciate the tour that you've given us and I think
there's room for improvement but that's true in every facility. I want to thank you again.
Appreciate it very much. >> REYNOLDS: And when will I be having your
report? >> ECKERLIN: Oh, that's an important question.
In two weeks. >> REYNOLDS: Okay, very good.
>> ECKERLIN: You can hold me to it okay. >> REYNOLDS: Thank you.
>> ECKERLIN: Yes sir. Thank you. >> NARRATOR: Once you have received your energy
assessment, you will need to notify EPA. Initial notification of compliance status is due by
July 19, 2014. Be sure to keep your assessment with your records.
You can learn more under the reporting and recordkeeping module in this series.
Assessing your energy management practices and program can help you identify operational
and organizational strategies necessary to support and maintain boiler efficiency.
EPA, through its Energy Star program, can help you build into your energy program critical
practices that will keep your boilers operating efficiently. EPA's EnergyStar website provides
valuable resources to help. Department of Energy, through its Advanced Manufacturing
Office, can help you understand the energy assessment process and assist you in obtaining
an assessment. DOEís energy assessment webpage provides helpful information and resources.
[MUSIC]
Energy Assessment - Module 3 of 4 SCRIPT for EDIT 07/18/13
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Shooting Script CLIENT: Environmental Protection Agency
PRODUCER: Marsha Winstead, WinRock Productions, LLC