How To Draw a P&ID - P&ID Tutorial - Reactor & water cooling

if you followed my four step guide to draw and paint ideas the first thing you do is is draw yourself a PID map and and figure out what's what you're going to put on the P&ID so we kind of already thought that one through a little bit for you you might want to move the borders around a little bit that's fine as long as we get all the P and ideas done that's that that's what that's what counts the next thing you probably will want to do is you probably want to have thought through the sort of top-down mass balance and and and flows around the process so you probably want to just take a sheet of paper and just think through what are the major controls that need to be on there just to control the whole process so feed flow control maybe pressure control in a couple of places so that that's a good idea just do it with a PFD almost that's that's good enough to get you started on it and then and then you really can you can kind of dive into the actual individual P and IDs now I'm going to I'm going to sort of quantify this this is a lesson in drawing P and IDs but there's going to be some stuff that we leave off these peen IDs there's going to be a few things like line line numbers and line sizes specs that we're going to leave off on these paint IDs so really these are kind of a hybrid between what people will call a process flow diagram and a full set of peen IDs or maybe just better refer to as a first draft set of p90s that the process engineers would work on and then there's a whole bunch of other people that would get involved in the p90s and add a lot more information too so with that kind of said what we really need to do is we need to make sure that we've got all the in line instrumentation on the P&ID use because our next step really is is to get the pump sized and unless you know what the inline instrumentation is you really can't get the pump size you don't know whether you've got a flow meter in the line and you don't know whether you have control valves in the line or not we've got to get that under under under control and so this exercise will do a very good job of getting that it will also give you a really good sense of the controls that need to be on a full process so and we're not going to talk just about the basic process control we're going to talk about the interlocks as well so I think that'll be a nice little extension to your existing knowledge about controls so the next step after that really is to think well we've got a certain number of pieces of equipment we want to put on the P&ID so we need to kind of organize it a little bit this morning I got up and I thought it through a little bit and threw together a couple of just rough sketches of P&ID is just mostly thinking about where I want to put the equipment on the on the piece of paper and I think I was fighting with myself as to whether I want to put the the steam drum on the left-hand side or the right-hand side of the reactor and it probably doesn't make much difference in the end so basically the first step then is to is to get a title block on the drawing here and start to lay some of the some of the actual equipment onto the end of the drawing so let's put the major piece of equipment on here we know we have a reactor so let's get that on there and we'll just draw it kind of like a heater changer because we know it's going to look like a heat exchanger like that and like that and we'll throw some tubes on there for now you may want to come back and revise this a little bit later a little bit of a tilt here and we also know that we're going to have a steam side of this in a steam drum system so let's draw the steam drum and we'll put it here give ourselves a little you want to get as much space here as we can because there's going to be quite a bit of instrumentation on this steam drum okay we we probably want to put our our normal liquid level on here and we'll put our low liquid level on here for now and we'll put a high liquid level because we know this is a separator so the high liquid level is going to be somewhere on halfway so that seems pretty straightforward the the other aspects that we need to get in here are we need to put a cooler on because on the next P&ID we go into the separator so we're going to show ourselves a little bit of a cooler and maybe we'll put it roughly here this marker is not the darkest marker and try and draw its I draw with a kind of sideways then it gets a little darker like that now you guys should you guys should have an equivalent list and you probably know what this equipment looks like I suspect because of some of the temperatures involved this may actually be a YouTube u2 changer so maybe we'll draw that as a you tube heat exchanger once you show a little couple of little youtubes in there just to make it a little bit more clear and there's different conventions around how you're going to actually show equipment but I find it really helps to show the pieces of equipment with a sense of what their how they're going to actually be built ok so there's there's our cooler and we're going to need some nozzles so if you want to if you want to make the nozzles look really nice then you can draw them like that the other convention is to just draw them as a tee that like that if you want to make them really cool-looking you rub that out you make a little bit of an ellipse and they look and they look actually like almost real vessels oh man this marker is going to cause me problems isn't it so if you do that it just gives a little bit more of an artistic look that's the art of peen IDs ok so that's that the other piece of equipment we've got to get on there is looks like we have a cooler going into the reactor for now so let's draw that we might not actually have space on here to do that but we'll try and get it on there this may be a case where we have to push it onto one of the other peen IDs I will put it here and it's pretty hot so again is it I don't know what did you guys do anybody sighs that is a you tube heat exchanger or how did you saw a floating head or how did you guys size that anybody remember should I just draw it as YouTube then it's the cooler and going into the reactor what's that called feed cooler or something like that I can't actually see it on my on my drawing so I think it's probably called the feed cooler I'm going to draw it as YouTube here we go okay so we have our reactor our steam drum those are the two major pieces of equipment our feed cooler which put some nozzles on that Wow does anybody have a better marker this is really dodgy it's the best one I have but yeah I steal it from you is it better than mine you lie Haley's calling you a red one Noah was like oh there we go oh that's that's it those are usually good yeah I know these are usually good I lost I lost my version of this oh that's good yes these are awesome thank you let's use your let's use your marker I'll buy you a new one there we go that's what we need much better much better now you can see it so afraid the camera wouldn't even see it okay better okay that seems pretty simple right do we have any more liquid levels we have to put on here not really do any more equipment do any more equipment what do you guys think are we missing any pumps or anything like that put some nozzles on here while you guys think about whether we need pumps or not anybody see if we need any pumps or not you got asked you got to be thinking about this game what do you guys think any thoughts we need a pump what do we need a pump for pump water through the jacket okay we might okay so if we didn't do that we're going to need to put the pumps probably at ground level we're going to put them in here okay I think we can run the the jacket with a thermo siphon might be debatable but I think we can run it without without actually having a pump we just need to have the water we need to have the elevation is far enough that the liquid level in here is going to flow into the jacket of the heat exchanger it's going to boil it and percolate it back up into the end of the steam drum like that so we don't need a pump for that to think we need any other pumps so what kind of what kind of pressure we operating that steam drum at any thoughts 700 what 700 what was it kPa okay so I'm just going to write that down here 700 kPa and so that's 7 bar what's the saturated steam temperature at 7 bar 165 Celsius okay so if our process is at 220 right that's where roughly where our process is in terms of temperature we're going to be probably a little bit too cold at 165 we probably need to be closer to about 200 degrees Celsius on the steam side which is going to boost this pressure up to something higher than 7 bar where did the 7 bar come from that's the blower feed water right right so we've got boiler feedwater at 7 bar coming into the sheet but we need to use it at 200 200 degrees Celsius well that's going to be more like 10 or 12 bar or something like that I am working I don't know whether you guys have got the numbers handy or not anybody got high sis open check the check the exchanger operating pressure maybe I'm not sure whether it's built into that bond or not so I would say though that if we've got 6 bar coming in the sheet and we're trying to operate the steam system at 10 or something like that bar we need some feed pumps in here so my recommendation then is to put some pumps in here and if you think about this if these pumps fail and we lose our cooling water to the reactor what's going to happen what's the what's the implications of losing cooling water to the reactor reactors going to get extremely hot maybe we could certainly damage the catalyst and anybody work out how much cattle what the cost of our catalyst is in the last assignment over a million dollars okay so so if there's a power blip and we lose cooling water in a fairly short period of time you're going to be writing a check for over a million dollars how many power blips do we get a year several could be writing several several million dollar checks every year that could be a bit of a problem so what we might want to do is we might want to have an electric motor and we might also want to have a steam turbine to keep the pump running so one pump with a shaft electric motor on one side of the the pump and a steam turbine on the other side of the shaft and maybe the steam system is a little bit more reliable than the electrical system in either way we can we could run one or two of the pumps on with a backup system so the other thing you want to also do is you want to have two pumps so because the pump it could be a power failure but it could be just a failure in the pump as well so we would definitely want to have redundant pumps here can you follow that that sort of line of thinking does that make sense to you guys okay so whether we put a steam could get away maybe with putting a steam turbine just on one pump but it might not be the best idea to do that we might want to have a motor and a steam turbine on both pumps so the reason you're going to have two pumps probably is you want to do maintenance on the pumps on a regular basis and so you want to be able to flip those pumps back and forth put start one and run the other might rotate those motors and things like that have a good eraser here I'm just going to use this and move this stuff around a little bit oh that's ugly okay so let's put the motor in I'll put the steam turbine in like that okay okay so that's I think all the equipment I miss any equipment you guys seen any other equipment we need to have on there so it's really just a question of piping it seems pretty straightforward so we know we're going to have boiler feed water coming in the side of the drawing here it's going to come in from a utility peen ID so we don't need to show the drawing number for that because we haven't drawn the utility P and ID's yet we've got our lower feed water coming in here now what you're going to find is the pumps this one's kind of these are special pumps crews are going to put steam turbines on them but in general when you put a motor on when you put a pump and a motor on there's like a kind of a standard envelope of stuff that's just going to basically come my recommendation is maybe just draw one of those on on some graph paper and then photocopied a bunch of times and then when you want to when you're drawing your big drawings you can just kind of move those around until you're happy with where they're placed but the standard sort of the standard controls here is to motor control center in that's shown with an interlock symbol and I in a diamond and I know this is kind of cramped down here but you'll see why in a second okay and then we need to have a local start/stop so that's an HS in a balloon and a dashed line from the HS down into the interlock so that gives us the ability to start and stop the pump and also to put it into Auto so we're going to write on off and auto when it's in Auto that allows the dcs to start and stop it on off auto like that and then we also want to know whether the we want to be able to start and stop the pump from the computer control system the DCs and so we're going to put an HS with a box and I circle around it and align through it like that so that gives us the basic controls for the electric motor there most of the time in terms of the piping now you'll want to know what the pressure is on the inlet to the pump you'll want to know what the differential pressure is so most people measure the inlet pressure by putting a P I in there so we need to do that so there's our pressure gauge P I most of the time the pumps actually are the piping actually goes down align sides going into the pump so you can show a reducer now it's confusing that that looks like a turbine it's not a turbine it's a pipe introducer like that so that's going into the pump and then if you start to work backwards one of the things you probably want to have when your pumps is while we need to be able to switch between the pumps so we need to put some manual valves like that and it's pretty common to have some dirt in the water system during startup so people will put a why strainer in and if you want to Google what a why strainer is you spelt like this so put yourself a little wise strainer in your pumps that will save you from destroying your pumps and put a little valve on the Y strainer because you need to be able to drain the Y strainer okay so we've got an isolation valve a Y strainer you might sometimes people put a drain valve in there as well or sometimes they'll just drain off the Y strainer and then a pressure indicator and then a reducer into the pump and you're pretty much set for your pump now you come out of the pump and you want to put a pipe expand your end pipe expansion in so that's just a reducer put in backwards and then you probably want to know what the discharge pressure is on the pump like that so put a PI in there and then generally you want to put a check valve in so the check valve prevents a liquid or water in this case from flowing backwards through the pump that's particularly useful when you want to start the pump up and then we need to put another block valve in so it's another manual valve and then we can join the pumps together so then we're just basically going to duplicate that we'll come back and do the controls on the steam turbine later is they're called they can be a little complicated like that and we're done okay so I kind of showed you the controls the piping and the valves on one all in one shot that's kind of the block that you want to just carry around to different places now let's pipe the whole process here and then we come back into the controls and the rest of stuff okay so this is going to give us our water supply into into the steam drum so let's draw that in and we're going to have to put some controls on this but I'm going to draw the line and then just go back and erase it so I can put the controls in okay so we've got water coming into the steam drum the water is going to come down oops here we go racer doesn't work very well okay and then this has got to come back into the steam drum so we'll need to come in either on the top might as well just do it on the top then kick come in on the side if we want but most will come in on the top and we're going to do that pretty straightforward we're going to get over there so we've got our sin gas feed here and that's coming from sheet on that computer shutdown what she does that you guys in the above III okay the other give it a sheet number or just give it a different drawing number two different conventions there doesn't really matter okay and that's got to go in here we're going to come out here and we got to get into that reactor there so we've got to weave our way around here a little bit I think I'm going to cut it across here and okay so horizontal lines break vertical lines when they're major process lines you could argue that this syngas is more important than the utility water which case it should break it no matter what direction it is okay go up here break myself break my way through this one then I'm into the reactor nice if you want you can throw a couple little arrows on there just to help people understand what direction things are going just cosmetic really voila okay that's the syngas going in then we probably would have put the syngas on the shell side is that where you guys put this in guess on that heat exchanger out through there and we need to go off to what sheet numbers I think it's sheet two or three or something like that I get my computer there we go she too to the three-phase separator okay kind of squeeze it in my title block here I'll move my title block later okay so that's the syngas coming through cooled through the reactor through the heat exchanger and away we've got our boiler feedwater coming in it's coming into the steam drum here it's mixing with the the returning water coming down being boiled through the through the reactor back through here what are we missing are we missing any major lines cooling water yeah yep we need some cooling water so I think because it's YouTube and it's horizontal what I want to do is bring my cooling water in the bottom of the heat exchanger so it floods upwards and pushes any air out of the heat exchanger so I'm going to do it that way and I'm just going to go right off the sheet here we're going to put some controls on here so hang on to your hat there that's that one we're going to need the same thing here I'm a little bit cramped in here but I could draw it coming in through the sheet here I could also extend that line down and pick it up just try that see if we can make that work definitely not gonna have any enough room for the steam turbine controls that's that and now this is a utility and it's horizontal so you would think because it's horizontal should be breaking that line but because that's a major process line we're going to break the utility instead there you go and I broke the utility around this one both of them are basically utilities so horizontal is breaking vertical sounds reasonable I missing anything else yeah okay what am i what am i missing though paper exit yeah we got to get rid of this team somehow so let's put that here so steam header okay now do we have pretty much everything are you guys saying I miss anything yet now okay so now we need to work through our controls then if we have them if we haven't missed anything at this point time where should we start our controls let's start with the process maybe so the syngas feed and the control system for the syngas feed is probably off the sheep so or it is off the sheet so let's let's not worry too much about whether it's what the flow rate is trying to control the flow rate it's coming through it's being cooled through this heat exchanger we might be interested in what the actual temperature is going into that heat exchanger are coming going into the end of the reactor so we probably want to measure the temperature here we may not actually control change my mind we do want to control that so let's put it a little bit closer to where we're going to put the controls for the cooling water there's the TE there we're going to put a TI C in like that and then we need to put a control valve in to do that control so let's put that in right there let's fail it open because cooling this system off is probably a good idea in the event of a failure like that and most of the control valves are aligned size smaller than the actual pipe so it's a generally a safe assumption that you're going to need a pipe reducer on the inlet and the outlet of the control valve it may not be the case but you might as well throw it in there because it's probably going to end up that way so there's a simple simple single-input single-output control loop you might want to give the valve at an instrument balloon so because it's on temperature control then it's just basically a tea a temperature valve and we might be concerned with whether that temperature gets high or low so put a temperature alarm high and attempt to arm low in there it's conceivable that we want to isolate this from the cooling water so we should probably put some manual valves in there and I'm boxed myself out in terms of manual valves theirs in terms of space so see if I can erase that a little bit move it around a bit like that there you go okay so that's easy let's keep on going the next thing we will probably want to do is is we probably want to know what that pressure is into the reactor this pressure is going to be an important factor in the molecular weight so let's put ourselves let's add a pressure indicating transmitter put that into a pressure indicating controller and somewhere that pressure in a KD controller needs to control something - and we have decided where that pressure control is going to come from but essentially it's got to come from the system that is doing the pressure control for us in in this whole big loop and I'm going to leave that for you guys to think about a little bit because there's a couple of different variables that need to be picked up to control pressure pressure in the system so that's that we might even be interested in what the composition is so if we have lots of money we could put an analyzer in on that single speed put an analyzer indicator in like that may not control the process off it but it might be really good information just to have in the control room and if you want to indicate what we're actually going to be measuring then you just put that beside it so we might be measuring the CEO and the h2 or whatever else we want to we want to measure there so an analyzer is probably not a bad idea in this in this particular process onwards and upwards coming out of here the temperature might be higher or lower so we are going to need to control the temperature coming out of the reactor so we better measure the temperature and then we put a better put a pressure temperature indicating controller in like that and we most certainly want to have an alarm on that probably high and low and then we're going to send that signal somewhere where we going to send that signal to you guys how are we going to how are we going to control the temperature in the reactor thoughts dreams the water through the reactor if you say Rudy sorry you just gotta say it louder because I can't hear you over there slow rate of the cooling water kind of you guys can read this qe coos you a delta delta t lawn right with an F factor in there if you needed it where does flow rate come into that because that's that's what dictates the heat transfer in a heat exchanger not the flow rate not directly the flow rate anyway if we add more boiler feedwater we're just going to overflow this game drum yeah we could if it got too hot we could go back and we could say let's reduce the the flow rate of sing gas but most likely the pressure in the system would start to drop okay so if we change if we change the pressure of the of the steam drum here then it changes the boiling point the changes the boiling point is changing the temperature if it's changing the temperature is changing the LM TD of the heat exchanger bingo so what we need is what what do we need to do that we need to measure the pressure okay so let's get that on there let's put it here put a pressure transmitter in like that so we got a transmitter now what do we do now what else do we need we need to regulate the vapor flow rate out of the out of here exactly okay so we need to basically put a control valve in right like that we want to fill it open or fill it closed I think they lit open who thinks we should fill it open who thinks we should failed closed only one person is willing to stick their neck out on this one eh well let's try it as fill open and we can come back and look at it from a hazard analysis later on so they'll open by putting a little arrow sticking up there sorry there we go tidy it up a little bit okay what else do okay so we've got a valve now what do we need to make that actually work we need a we need a controller right okay so let's put ourselves let's give ourselves a pressure controller here if we can we can go from left to right in this situation so this makes it fairly easy to read hopefully we need electric wire going from the constrains Manor into the controller and then electric wire from the controller into the valve okay that's good but how do we relate that temperature how do we get that temperature to control that pressure controller so what we need to do right is we need to be able to adjust that pressure to anything we want so the set point of that pressure maybe it's 10 bar maybes 12 bar maybe it's 10 and a quarter bar or whatever the pressure is we want that that we want that pressure to be adjustable and we want that pressure to be adjustable based on what the temperature is down here does that make sense so what we need to do is we need to send a signal from that temperature controller to that pressure controller what we really want is we want the setpoint of that pressure controller so I'm going to put a little SP on there and that setpoint needs to come from the output of that controller right there and so since they're both in the computer control system all we need to do is draw a software line piece of khang we just need to figure out how we're going to wind it around that's all and that is called a cascade loop you guys everybody see how that works makes sense the other thing we might be worried about on this reactor is is differential pressure so if the catalyst is doing something funny we we might want to know that so let's put a pressure differential indicating transmitter in with a signal into the DCs so a pressure differential indicator in the dcs like that and we might as well just pick it right up off the reactor itself like that put some valves in so we can isolate it if we want to here we go I guess is some insight into what's happening in the reactor we know we know the inlet temperature we know the outlet temperature we know the inlet pressure and we know the differential pressure across the transmitter there with a differential pressure the only thing we don't really know is what the temperatures are actually in the bed so it'd be nice to know what the radial temperatures are in the tubes would be nice to know what the longitudinal temperatures are down through the reactor we might want to try and do that it's going to be really tricky to do though because it's a bunch of tubes and we would somehow we would somehow have to get a temperature element down into the tubes like this and you'd probably want to pick off a couple of temperature elements like this problem is the temperature I'll depend on how big the tubes are themselves the the actual temperature thermal Wow or whatever we're going to use to do that could kind of interfere with some of the flow rates so it may not be super accurate and the temperature element is probably going to fail at some point in time as well so but anyway you might want to try and do it anyway not uncommon for people to try and get some sort of temperature measurements into the reactors that's going to take that would take a long time to figure out how we're going to do that exactly because of the mechanical design of what we've got there okay we got anything else we come out of here then we would need to cool it and we're trying to hit what did you guys optimize that temperature to what was it anybody got a optimization to optimize temperature for the exit of that cooler 65 okay so we need to measure the temperature now one thing you'll see is is I try and put the temperature element in an elbow like that because that's essentially how they're that's essentially how they're going to be installed here's a pipe elbow here and they're going to put a thermal well into the pipe element like into the pipe like that and then they're going to insert the the TE into the thermal wall like that and so you have really good flow and good turbulence over the over the T so if you can you try and show it on the on the P&ID like that and we need a tempter indicating controller in order to do that like that we need some cooling water controls it's cooling water sighs fail it open actually what we can do is come down here there okay so that's our cooling water let's put a manual valve on that and a manual valve on here we might actually be interested in knowing what the cooling water supply temperature is and the cooling water inlet pressure so we can put a P I and there's a kind of a cool little device that actually combined two P I and a temperature and a temperature gauge all in one so that's kind of handy to have and we'll just put that on here as well if you had to you just do it with separate gauges as well piti like that that gives us inlet pressure inlet temperature just in case you want to walk out to the field and just actually look at what the differential pressure of the heat exchanger is on the water side is that it for the process side it's not much else we can really control here is there the flow rate control and the recirculation control is all done on the compressor so if you want to actually control flow rates you've got to go to the compressor PID and start to manipulate the the way the compressor operates so you'll have to probably take that P&ID that we did for the PHA and a bunch of you guys notice that the speed indicating controller on that compressor kind of goes off the page like this and it goes somewhere else and so you need to hook the controls up for that okay so that's the process side now let's look at some more of the utilities here the steam side I think it's going to be a little bit complicated here we know we have water coming in here water circulating around through here we might be interested in what the water temperature is going into the reactor may not be something we're actually going to measure sorry what we're actually going to control off but we might be interested in knowing what it is like that we could in theory actually if we really want to control that temperature there no I won't do that I was going to say we could cascade it into that we could control the water temperature instead of the process temperature but it's better just to control the process temperatures more direct so let's just make it an indication so that people can look at it any time they want it goes through the heat exchanger assuming there's not a lot of change in pressure here it's just changing phase so it's coming out of here to phase we measuring the temperature isn't going to be terribly useful you might want to do it anyway but it's it should basically be reading the same temperature so the only difference is the fact that there's going to be a slightly different pressure there so you can put it in there if they're different then you'd probably start to wonder it's trying to troubleshoot the process baby okay so that's kind of the water circulating around we might be interested in knowing what the flow rate is so if you've got enough differential pressure here you could put a flow meter in you can maybe try and find a very low pressure drop flow meter so let's put a flow indicator in there that might be useful just to know that just to know that you've got decent flow here if you had a pump in here you would definitely want to put a flow transmitter in there so debatable whether we want to put a pump in not in there or not but but certainly we would have a transmitter in there okay so now we've the whole issue here is if we lose water into the reactor it could be a very costly mistake so we want to make sure that we always have water going into the reactor and for the water to flow through that reactor properly we've got to hold the liquid level at a fairly constant level so right off the bat we know that we need to have a level transmitter and a level control of some sort so let's put that on there right now we need a nozzle probably going to have some valves I'll tell you right now it's going to be a 3-inch nozzle okay let's draw the level transmitter out here so we give ourselves a little bit of space okay that's good now the transmitters all electronic you may or may not actually trust the level transmitter so you might actually want to put a sight glass on the vessel as well that's pretty common in these in these situations so we can draw the sight glass here or we could draw the cyclops here another sometimes people if they're really cramped for space they'll actually draw the sight glass right on the kind of on the vessel it's a little bit confusing for some people but I'm going to do it just to kind of illustrate how that would be sort of shown so we'd show the nozzle like that we chill a valve like that and a sight glass is an LG so we do that come down here like that and just draw kind of like that so you can kind of see that it looks like a nozzle on the side of the belt on the side of the vessel it's just I could have just as easily put it here because I've got lots of space there all righty now what so we need to control the level how are we going to control the level in here how do you want to control the level you guys buts you mean the pressure control valve no because we've already got the pressure control valve tied up in an existing control loop we we'd end up with two controllers trying to get inputs from from two different measured variables that wouldn't really work any other thoughts how about the feed water pump the level gets low we put more water in good good call okay so let's put a control valve in here now I want you to think really hard in your experience of opening a pop can our pop bottle when you crack the lid on the pop bottle when I was to the level the level drops okay sometimes jobs because you're drinking it so all the gas starts to come up what happens what happens if you start to have that gas come out of solution that what happens to the level the level starts the level starts to rise sometimes it for a little while and then the level starts to drop again so I get Dyna it's like a dynamic thing right if we start to open and close that valve right there we can expect maybe the level to initially if we start to drop the pressure a little too quickly you can expect maybe the level to rise a little bit and then maybe for it to start to drop it starts to drop because as you drop the pressure we actually boil more steam right out of the steam drum so there's situations where that level might actually be moving around and that level transmitter might be measuring it but it might actually kind of be a false a false level measurement so we may not really want to respond to every little bit of blip in a level there what we might want to do is measure the flow rate here hold the flow rate fairly constant so we'll put a flow indicating controller in here and then our level indicating controller here can then send a signal down into the flow indicating controller and if we really wanted to we could even we could even send a signal from the pressure controller down so that the flow controller knows that the pressure actually is being manipulated and that's going to be a little complicated here so we're going to cheat we're going to do that and if you go on google three-element drum level control you get more of the details of how that control system actually works you can even write it down here three element drum level control my my recollection of that control system is a little hazy I think I've got it set up right but we might want to go and just check just to make sure I've got that right I'll go have a look after class maybe and if I make any mistakes I can just mark I can just revise them in red that's pretty good now one hazard we've introduced here is we probably want to we may not want to fill that open actually we want to fit we may fail that closed that might introduce some hazards as well or we fail it open well let's just fill it open I know I'm changing my mind back and forth here if we fill it open then we might it potentially create some serious hazards here because we could potentially flood the steam header and that's going to create some serious problems if we fail it closed then we could potentially lose water into the end of the reactor and we can potentially damage the catalyst at some point in time this is a this is a question of I don't think there's a right answer or wrong it a right or a wrong answer here either way we are in deep trouble what you could do actually here's something you probably haven't heard of failing last position fail in last position looks like this that makes the control valve a lot more expensive it's tricky to do that but that might be the way to solve that so I think that's the basic process control system did I miss anything we're controlling the inventories in the system so here's here's our inventory of water on the water side our inventory control on the gas side is really there there really is no control valves on the gas side so the inventory is really the inventory the whole loop and that inventory control is kind of done with this P I T and P ic system and and some other manipulated variable the only thing maybe now to add is some safety systems here if you've been listening to me talk the last couple of days if that valve for some reason fails closed on us we need to have a way to send that water back to its supply system so that we don't deadhead the pump we don't want to have the pump just turning and putting power into that water and heating the water up we want to send a small flow back so we're what's known as a minimum flow bypass and it's all basically here okay so well if you water return okay that's that couple of other things we probably want to put in here you probably want to have a pressure indicator on here so we can put it off here put off the same nozzle if we want like that we know what the temperature is okay so we know the temperature the pressure the level we know what the flow rate in is we don't have the flow rate out of here we actually might want to know what the steam flow rate is so this might be a case where you actually want to you could create a cascade loop here as well and an F I in the DCs there so we know what the steam flow rate is going into the header that's a pretty common thing to want to know we're not gonna we're not going to try and control the steam header pressure we're just going to basically put steam into that header pressure and the header has to basically deal with that pressure or else get rid of the steam somehow now we need is probably some interlocks we need some safety systems here so if we start to get a low liquid levels here we could be getting into ourself are getting ourselves into trouble here so we might want to automatically start a pump up if the level starts to drop so what we should do is put a level switch low let's make it a Lolo okay this will have a level alarm high and a low and then that level switch low we maybe want to tie in to starting the pumps so we're going to do that basically by tying the control systems in here to the motor control center on the pubs like that so that level switch level switch Lolo is now capable of starting the starting the pumps probably good idea if if we got to a we might want to have a whole bunch other look we could have a low low low if we wanted to so for instance if we got if we got to an even lower level we might want to send that signal to an interlock to shut the syngas feet system off we could we could do one or two things we can actually isolate the reactor stop the syngas going into the reactor by putting a block valve in here or we could stop the compression system that's putting natural that's putting the syngas in another way we could do it is actually we could just open the the vent valve on the purge valve and just dump the contents of the reactor out to out to flare so I would call this the reactor shutdown interlock I would put a note here our SD reactor shutdown and then however we decide that we're going to actually do that shut down basically there would be another interlock like that on that other P&ID that gets that signal and activates it okay so we've got a low level here we've got a low low we might actually want to have a high level we've got a we've got a high-level just in software here so that might be good enough the only thing that's a sort of unsatisfactory about this is the fact that everything is your you're trusting the level transmitter so if the level transmitter fails for any reason then you're in trouble so you like you might be smart to do one of two things you might be smart to put a couple more nozzles on here with level switches like that and a level switch hi hi like that level alarm hi-hi like that in the DCs Oh No and maybe what you would do is actually do the start-stop of the pumps based on these level switches instead of the transmitter you could do it on both actually so you can easily in the software if either one of those basically goes low level then like that if either one of those low level measurements is detected then we're going to start the second pump so whichever pump is off we're going to turn on there's one thing that I was interested that I would be interested in knowing is how much pressure those pumps are putting out so I would put a pressure transmitter on there so that if the pumps for some reason are are not putting enough pressure out we could be alarming on that and we could be thinking about shutting the reactor down or even if we wanted to we could prevent the reactor from starting up unless we've actually got boiler feedwater pressure that might be a smart thing to do as well I think that's pretty much it oh I know really founds really Phelps we've got a potential bloody hazard here we need to make sure we put a relief valve on here there that looks a little bit confusing because it doesn't want in this team lining host atmosphere - atmosphere and that's our relief valve set at whatever our set pressure is okay get rid of this interesting what the actual operating pressures are at this point in time it gets messy with controls a when you start to really layer the controls on I think we've only actually probably just started this in terms of controls I could see us I could see this getting a little bit more complicated through here so if I was going to redraw this I think I'd start to shift stuff that way a little bit and give myself a little bit more space on than p90 so that's why doing it an eight-and-a-half by eleven is is a good idea just to just to do a prototype of your IV P&ID and OH what happens in your kettle over time it scales do you think we're going to have scaling in this system why not you think we will are you sure 96 97 % yeah you bet your career on it you would who else wants to bet we're going to have scaling or not have scaling I think we're going to have scaling what are we going to do about it a scaling what sorry yep we definitely we're going to have that boiler feedwater is going to be is going to have lots of chemical treatment in it but no matter what you still potentially have some scaling and some solids build-up and things like that you can't possibly have completely pure water we're going to we're basically going to pour thousands of pounds of our thousand pounds of water in here per hour we're going to boil it out of steam we're going to be left with the solids that came in with that so even if there's parts per million of solids that's going to build up over time that's going to be a problem so what do we do about it thoughts a water softener that this water is already soft this this water is as good as you can you can get it you're going to do what a manhole not a manhole now now there will be a manhole on the vessel but that's not a way that's not a way to treat to handle the possible water that's going to scale what do you guys think your chemical engineers you can probably solve your way through this now actually increase in the temperature tends to stop cause stuff to scale up more the solubility usually goes down with higher temperatures of some of those decrease the temperature yeah but the temperature is being controlled by the reactor you know any choice over the temperature any other ideas you're thinking about it at least what else can we do shut it down and clean it yeah okay could do that might have to do that anyways we can do anyways we can do it kind of continuously anti scaling that's that's already built into the water coming in here it's got its got a nice chemical treatment system but still it's not good enough what else can we do No can you design it for scaling um I guess you you could sort of design it for scaling but look at what look that's well what can we what can we do to try and get rid of those solids get rid of that that solid build up that scale build up maybe maybe that's gonna be tricky those gonna be heavy stuff that's gonna be heavy stuff where do you think where do you think this stuff would be in the bottom yeah I might be might be in the might be in the bottom here that's true yeah might be it might be kind of circulating around as well right yeah well what do we do yep now we could put a filter in maybe yeah yeah we can put a filter okay like put it where would we put it going in here yeah but that water is pretty clean going in Michelle you got somebody is a manual drain okay we could put a manual drain on there yeah what are we gonna do with the manual drain just like have a bucket there and you guys say it a little louder I can't hear you sir now let's make it small a drain a drain so how does it house it drain going to help us here so just a purge for the liquid okay and then we send it where we gotta get it up we gotta get off the sheet somehow that's going to be tricky how about if we go through here and because it's kind of a utility not a process we're gonna break it that way this we're gonna break like that okay how do we we put a manual valve on that or what are we gonna do how do we if we just leave that like that then there's going to be no water in the tank right it's just it's gone so how do we what do we do put a manual valve on okay like that and then how often do we know when to how often do we know when to open it or close it just a basic level gauge why the level the levels here right so yeah we could and you could drain a little bit off except of the level would probably refill as fast as you can drain it out of there can you see the that you see the solids you mean or see the level you might see the solids I doubt you - the solids because you really don't want to have that many solids in there you could you could be measuring conductivity yeah because the conductivity will go up is you have dissolved solids yeah so we could put an analyzer in there on conductivity so we could basically put a nozzle in or we could pull it off here let's pull it off here maybe analyze your element conductivity analyzer indicator conductivity yep we get to that mr. line okay no okay so we're gonna do that we might as well make it a controller right what are we going to control what should we control how about flow-rate yeah that's messy let's just fix it so it looks prettier like that okay so now what now what you can do is you can say based on conductivity we'll just basically purge more water out of there and this is this has a technical name it's called blowdown the only problem is there's quite a bit of heat in that water so you might end up if you start to get clever and start to think about this you might actually want to put a heat exchanger on there and maybe preheat water with it because you can imagine that's one of the energy losses in a system like this do we miss anything else I think that's probably it

Channel: CHEE470

Views: 140,589

Keywords: Chemical, Engineering, educational, Drawing (Visual Art Form), Education (Professional Field), P&ID, PFD, Process Flow Diagram

Id: 9WD-ZGXPDn8

Length: 83min 54sec (5034 seconds)

Published: Sun Nov 11 2012