Subscribe
Share
Share
Embed
Welcome to the FM Energise Podcast by Forbes Marshall, where we explore manufacturing excellence, energy efficiency, and industrial sustainability. This show goes beyond just optimizing processes, it’s about creating smarter, more efficient operations through industrial automation, digital services, and embracing the future with Industry 4.0 and IOT.
In each episode, we dive into topics such as process control and instrumentation, steam engineering, and thermodynamics, all while keeping sustainability at the forefront. We’ll also discuss how to create a great place to work where people feel valued, nurture a culture of trust and collaboration, and inspire positive change through social initiatives & CSR efforts that align with every organization’s core values.
If you’re passionate about leading your company toward sustainable growth, improving operational efficiency, and creating a culture that empowers your team, the FM Energise Podcast is your go-to source for expert advice and inspiring conversations.
ANANT
Hello everyone and welcome to a fresh episode of the FM Energise podcast. When we talk about steam and condensate systems, the thermal parameters often get a lot of attention. But to discuss another equally important area, we have with us Aditya Kanitkar to discuss the area of impact of steam and condensate cycle chemistry on performance of plants. Welcome Aditya. Yeah, thank you. So one of the first things I wanted to ask you is that water chemistry often gets not that much of an attention when we talk about plant performance parameters. But it is actually a very important area from the perspective of uptime, from the perspective of overall efficiency, unplanned shutdowns, things like that. Okay, so is it just the corrosion on boiler water tubes or are we looking at other parameters also?
ADITYA
If you talk about water chemistry, I will first get into why that becomes slightly ignorant area. Okay, if you see any parameters, whether you take a temperature, pressure or even parameters like vibration, they, you know, whenever they are changing from normal values, you have some alarms, you have some set points and you can take corrective action very quickly and you can restore them. Water chemistry is one of the, I would say challenges is today, if there is a disturbance in water chemistry, you will not see effect immediately. Okay, there will be sometime weeks, sometime months and sometime years to go before you actually see issues and effect of those disturbances in, you know, operational chemistry and that can impact multiple ways. It can impact in terms of efficiencies, it can impact in terms of life of that equipment like boiler or turbine or third, it can have impact even from a safety perspective. So you can come across the situation that there is a sudden failure of some parts and you cannot find out root cause in last two weeks or three weeks. So there are no events in last two or three weeks which are actually supporting that kind of failure. Because it's a very delayed effect. Yeah, so it takes a lot of time to actually see effect. So cause and effect has a huge, you know, gap sometime. And also, that means whenever such kind of failure customer or user is facing, they need to do really good root cause analysis.
So it's like a forensic study of failure parts of those high pressure parts, then you will find actually root cause back somewhere where you are not operating, you know, system as per chemistry parameters recommended, you deviated somewhere and then you see effect today. And that's why I would say one of the reasons that water chemistry is slightly ignored when you come from an operation perspective because their output or, you know, starting plant quickly, you know, those are first priorities for users. Whereas when you talk about issues related with the water chemistry, okay, it's not going to cause me any major issue tomorrow. So I can just ignore sometimes those alarms and go ahead. But that impacts in the long term in terms of efficiency of that equipment, in terms of life of that equipment, and also sometime there can be catastrophic failures of pressure parts which can lead to accidents also.
ANANT
Right. Yeah, so it's very critical. It's a very critical safety aspect also.
ADITYA
Correct. So that's why it's very, very important that this need to be monitored, circuits very continuously so that whenever you face any issues or challenges, you can look back for old data and actually come out with actual root cause of these failures and you can avoid those in future. Right. Yeah. So it's very, very important to have a proper monitoring of complete water cycle chemistry to actually maintain it on a required levels. Understood.
ANANT
So we talked about different water chemistry parameters. Correct. So can you give us a few examples of what potential problems or potential failures that you see if the water chemistry parameters are not correctly monitored? So you mentioned corrosion, for example.
ADITYA
So if you see water chemistry related issues, you can bucket them into, generally, broadly, in two categories. One is issues related with the deposition, and second, issues related with the corrosion.
Issues related with the deposition is like deposition of scales in tubes which will reduce thermal efficiency and heat transfer from one media to another media. And this kind of issues can also lead to some failures also. Like there is an under deposit corrosion. So there are deposits, then below deposit there is a localised corrosion, and then it leads to failures. Second issues apart from deposits is the corrosion related issues where actually part of metals corrode. So there are different mechanisms. So it can be reaction with oxygen, dissolved oxygen in feed water or oxygen which actually oxidise metal, which leads to failure of, you know, because then locally it gets weakened, there are pitting, and then there is a failure. Or there can be stress corrosion cracking. So elements like chlorides, chlorides, sulphate can cause stress corrosion of high pressure parts. And then there is something like a flow assist corrosion where actually because there is a water or steam is flowing through pipelines. So water corrosion products is actually scratching surfaces and it can lead to like erosion. So there are different corrosion mechanism, but broadly I can say these are problem related with the deposition, problem related with the corrosion. And both can need to be tackled when you operate any high pressure steam and water cycle or circuits. It can be power generation where you actually generate steam, use it on a steam turbine, get it back as a condenser, put it back as a Ranking cycle. Or it can be one Cogen plant or process plants where steam is generated and utilised in plant and then you recovered that steam as a condenser and put it back into system. In both cases, you need to be very careful about overall purity and contamination locations where there can be ingress of impurities in this cycle and can lead to failures related with a deposition or corrosion.
ANANT
That's interesting actually. And I also like the point that you mentioned with respect to both uptime and efficiency actually getting affected because of this. So I have heard about boiler tubes failing because of issues like corrosion, which actually shut down the plant for considerable amount of time, which is a huge loss to the operators or to the customers. So is that the only instance or do you see any other areas where both uptime and efficiency are affected?
ADITYA
Yeah, so I will talk first about, I would say uptime. So as you rightly mentioned that any failure of these parts will put down the plant for long shutdowns. Okay, so if you talk about boiler or steam generators, if you really see history of operations for any plants, you will see 40 to 50 percent of failures in boilers are because of water tube failures or tube failures. So tube failure is the biggest contributor of loss of uptime in boiler. Same way, if turbine is down, it is generally because of high vibration or any other issues. But if you again go back in a root cause, that is a deposition of impurities or salts on the surfaces of turbine blades, erosion of turbine blades, which lead to forced outages or shutdowns in these plants.
ANANT
Even the depositions can lead to vibrations, which are going to cause subsequent shutdowns. So ultimately, it boils down to water chemistry again.
ADITYA
Correct, so end of the day, if you go to root causes of any of the unplanned shutdowns or forced outages, they will mostly point towards water chemistry. And which is not yesterday or two days before yesterday's issues, those are long accumulated issues which suddenly forced to, you know, such kind of outages. Now, if I talk about efficiency, so you know, or everyone knows that deposition in boiler tubes will reduce heat transfer rates considerably, reducing thermal efficiency of the boiler. But at the same time, such kind of deposits on steam turbine blades. Okay, because steam turbine is very critically machined component where it is designed for a high efficiency where actually even slight change in the surface roughness of these parts of steam turbine can lead to reduction in efficiency. And you can imagine that a steam turbine which is generating 800 or 660 megawatt of power, and if there is a loss of even one or two percent efficiency, is a huge loss in terms of actual efficiency of the plant. Actual delivered output. Yeah, so to get a same delivered output, now you are burning more coal, more oil, more fuel. Right. So, best way if you can maintain purity of steam and water entire cycle, that will actually not only will help you to improve efficiency, but also will help you to unclamp shutdowns which are used cost. So, you imagine if you go for a shutdown for 800 megawatt plants. So, it's not just a small machine that you just started with a key. So, you need to restart. So, considerable amount of fuel you will burn for restarting. And whole process you will lose huge man hours as well as huge time in terms of loss of productivity. So, loss of productivity is actually biggest contributor when sun and sun shut down.
ANANT
Even if we talk about a power boiler or a cogent boiler, they are huge equipment. Even the shutdown will take considerable amount of time just for the system to cool down.
ADITYA
Yeah, so numbers says that for 800 megawatt, if you go for any unplanned shutdown and you want to restart again, in that one restart you lose something around two corrodes of Indian rupees. Wow. So, it's a huge loss of productivity. You keep aside actually cost of repairs, cost of equipment. Those are actually peanuts in front of loss of productivity and how many days you will lose in just restarting that plant.
ANANT
So, water chemistry seems like a very critical element. And do you see the industry actually waking up to this fact that they are actually monitoring the systems better? And if there are any gaps, where do you see those gaps coming out from the criticality perspective?
ADITYA
Yeah, so if I see an overall industry scenario today, if you go to all large power plants, there are slightly awareness is better. I would say some of the users are actually not only going in the depth of these measurements, but also trying to find out root causes, try to take a corrective action in operations to restore and to maintain plant at highest efficiency and uptime. But as I mentioned, steam as a utility is used not only for power generation, it also uses in process. So, there is a lot of awareness required in the process industry and users of water to boilers where still like cojen plants and captive power plants still need to go. There are a lot of improvement areas where I can see you can actually monitor this chemistry properly and take corrective actions automatically. As I mentioned, for water chemistry, most of the actions are taken manually. Though monitoring is done automatically or through instruments, but still actions today are taken manually. And then, because tomorrow, nothing going to fail. That's one of the reasons. But down the line, over the years, you will lose efficiency as well as uptime for entire equipment. And sometimes, some customers also face catastrophic failures of these pressure parts leading to accidents, which is actually a huge loss of even reputation for those companies. So, if you see all these aspects, I think maintaining water chemistry is a quite important aspect of operation which every user should be aware of and should get into depth of what needs to be done in terms of corrective actions.
ANANT
Understood. So, in terms of water chemistry, I mean, we discussed corrosion, which is typically accounted for with the presence of oxygen. So, do you think oxygen is always the culprit or do you have any other aspects like particulates or you have some silica content? So, what are the different parameters that need to be monitored closely for water chemistry?
ADITYA
So, as I mentioned before, we have two kinds of issues. One related with the depositions, one related with the corrosion. So, what cause depositions? So, first of all, elements like hardness-related causing salts, calcium, magnesium salts, and silica. These are major reasons which can cause deposits on a boiler parts or as well as on a turbine. I would say most of water to boiler, at least today, are using demineralised water. So, DM plants actually take care of major issues related with, I would say, hardness causing salt or salt causing deposits. Though some elements like silica are very difficult to take it out from water because of their nature, sometime it goes as a colloidal form, sometime it goes into reactive form. So, that kind of treatments need to be enhanced for avoiding deposition-related issues. But when you talk about corrosion-related issues, those are mainly because of if you cannot maintain pH or oxygen levels in cycle. So, when water enters into boiler circuit, once demineralising DM plant, this demineralised water also need to have some actions need to be taken in terms of enhancing its pH on alkaline side. So, we put some chemicals to enhance pH on alkaline side and also you need to take care of dissolved oxygen because any reaction between matter and oxygen is a corrosion. It is actually one of the areas. So, most of the feed water treatment for boilers are actually segregated or categorised based on how you are going to handle oxygen and pH together. So, there are different treatments which actually adopted for feed water of boilers.
ANANT
Okay, and this will also depend on the metallurgy of the boiler components.
ADITYA
Yes, correct. So, if you talk about boiler metallurgy, so in many circuits, I would not say only boiler metallurgy, it's a metallurgy of entire plant. So, if you have mixed metallurgy, for example, you have some iron and iron alloys because most of the pressure parts are made up of iron and iron alloys. But at the same time, if you have some copper cupronickel used in heat exchangers or condensers or LP heaters, then you have now two metals, two handles, okay, from corrosion perspective. So, you have iron and iron oxide, iron and iron alloys which you want to avoid oxidation and at the same time you have some copper cupronickel non-ferrous alloys where you want to avoid corrosion. Now, the problem is that when you talk about such mixed metallurgy, we say, you know, reaction of oxygen at different pH has a different rate of corrosion. So, in such mixed metallurgies, people are go for A, B, T, R treatment, all volatile treatment with reducing agent. What this treatment does, so you need to remove dissolved oxygen in totality from feed water completely to make it as low as possible, ideally zero. So, you use mechanical deaerators to deaerate water. In addition to mechanical deaeration, we add reducing agent which is we call oxygen scavengers like hydrazine, carbohydrate, which reacts with oxygen and kills oxygen in totality. And then there will be a small residual of these oxygen scavengers which you can monitor. So, by monitoring pH, dissolved oxygen, conductivity and residual hydrazine, you need to control actually dosing of this oxygen scavenger and pH boosters in A, B, T, R treatment. But at the same time, if you go for some circuits which are all ferrous metallurgy, okay, so now modern power plants are coming with only iron and iron alloys. So, they're going for alloys like P22 or P91, P92 for supercritical boilers. But their low pressure circuits or feed water circuit also includes carbon steel and iron alloys. So, if whole circuit is with a single metal, base metal, you can iron or iron alloys. In that case, you can actually go for better treatments also. So, new treatments were adopted in such plants which called AVTO treatment, all volatile treatment, oxidising environment and OT treatment, which is oxygenated treatment. Okay, in both these treatments, actually what we do, we try to maintain pH in a particular range and dissolve oxygen also in a particular range which will form a very strong oxide protective layer on iron which will be a very strong layer of oxides. So, oxygen will not penetrate through this layer to base metal and increase corrosion.
ANANT
So, you're actually monitoring oxygen. Instead of killing the oxygen completely, you're actually maintaining it at an optimum level to ensure that such layers are formed.
ADITYA
Correct. But to create such layers, you need to even maintain pH also in a certain band. So, pH will be maintained on alkaline side between say 9 to 9.8 or 8.5 to 9.5 in that range at various locations and dissolved oxygen is also maintained between say 80 to 120 ppb in that range. So, by maintaining these two, you can actually form oxide which is very strong oxide which is protective layer and there are some additional advantages also because in such cases, you are not dosing a third chemical in a process like oxygen scavenger which can have some other issues. At the same time, you can get lesser pressure drops in a steam water cycle and actually you can get better results out of this. So, these treatments are actually recommended internationally by IPWS, VGB, EPRI. They are actually now working a lot on these areas where you can actually go for these treatments. So, most of the large power plants already migrated from AVTR to AVT or OT treatments but still small power plants, captive power plants are on AVTR treatment because of mixed metallurgy in their entire cell.
ANANT
So, because it will require some capex also in terms of changing the equipment with mixed metallurgy components.
ANANT
One other question I had which is with respect to
ANANT
the changing load patterns. So, we are seeing a lot of renewables coming to the mix in a big way but they are unreliable. They are seasonal with respect to day-night cycles as well as season to season cycles. So, power plants tend to be base load still but their operations are no longer the steady state operation they used to be, maybe 10-15 years ago. So, are you seeing any operation related challenges coming out of it and how is it affecting the water chemistry side?
ADITYA
Yeah. So, if you talk about particularly thermal power plants till date, most of the thermal power plants were designed for a base load operation. So, they were say today my power plant is designed for 500 megawatts. So, people used to talk about PLF, plant load factor. So, my plant is operating on a 499 to 500 and one, you know, so it's on full load. So, whenever you're talking about such a steady operation, everything is like in equilibrium. Yeah. Okay. You know chemistry also will be in equilibrium. You will have very steady rates of dosing. Okay. There are very small disturbances in load patterns. So, small changes in the levels of drum. So, everything is quite constant. But as renewable is coming into grid worldwide, not only for India, you know, operation patterns are going to change. Okay. So, if you talk about today's situation in India in 2025, today 50 percent install capacity is coming from renewable. Okay. In a grid. That's quite it's an install capacity. But at the same time, if you talk about real generation, it's around 38 percent. So, you have something which is a 50 percent can contribute to power grid. But now, it's contributing only 38 percent. But you need to have a grid stability, you need to have a constant voltage and, you know, frequencies. So, your now thermal power plant is has a job to absorb these you know fluctuations in a grid. Okay. So, traditionally you were operating very steady load pattern, constant load.
Now, each after 15 minutes, your power plant is getting new schedule. So, each within 15 minutes you need to go. Every 15 minutes. Yeah. So, for power plant users, it's actually very, you know, you can imagine it's like a disruption in the way you operate plant. When you talk about water chemistry also, now as there is a change in pattern of load, you need to adapt to that in terms of to maintain chemistry also because you are deviating away from equilibrium to somewhere, you very dynamic situation. So, when you talk about thermal power plants, you can categorise into three critical aspects. One is a start-up because earlier you used to start plant once in a year, twice in a year. Now, you need to restart your plant maybe weekly once or some plants even, you know, so quite more frequent start-ups. So, ramp up you do and when you ramp up this power generation, you need to go through various pressures. So, lot of challenges in that area. Secondly, you will go for a cyclic operation. As I mentioned, each 15 minutes today, power plants are getting new power or load they need to generate and give it to grid. So, that also has a lot of changes in flow or pressure, sliding pressures, which also lead to some issues related with the chemistry. And now, you will see some of the plants which are not very efficient need to be put off when you don't need power. So, you will see more shutdowns. So, even during shutdowns, you need to preserve boilers and entire cycle because standstill corrosion is also a new challenge. So, all three regimes of operation will have a direct impact on corrosion rates, direct impact on depositions, flow assist corrosion. So, you need to monitor entire cycle now more rigorously and you need to take some, you know, corrective action more real time also in terms of dosing rates, in terms of control of dissolved oxygen or pH. Now, it's going to be more real time. So, a lot of opportunity there for aspects like monitoring these equipments.
ANANT
Understood. So, I get where you're coming from. So, if it is running in equilibrium, then almost everything is going there. You monitor specific KPIs, if they're deviating, then you take the corrective action. But with everything changing with the frequency as strong as every 15 minutes, okay, under that condition, all of this becomes very much active, very much proactive. So, the real time monitoring becomes a very, very important parameter in that case. So, I get your point on this. So, my question to you to follow up on this is that would you have any specific recommendations to people who are operating such plants in terms of what they should look out for in a way?
ADITYA
So, from a steam and water cycle chemistry perspective, there are a lot of parameters are monitored today. So, you have a pH, you have various type of conductivities, dissolved oxygen, silica, sodium. So, those parameters are required as it is. But those need to be monitored and somewhere they need to be linked back to controls. Okay. So, that is going to happen and that is required to be looked at how you can get robust measurements and how you can utilise them for controls of these chemistry parameters.
ANANT
So, basically you're looking at measurement, analysis, then corrective action and control. Yes. Hopefully, we'll see with the rise of AI maybe we'll see an automated version of this entire cycle also.
ADITYA
Yeah. So, that also AI is going to contribute a lot because, as I mentioned, now you have data for years and now you can actually go for a real root cause of issues with that data. So, that's also going to contribute. But at the same time, you may need to have some additional parameters you can monitor. So, they are getting more and more popular like dissolved hydrogen or turbidity. These are getting more popular because of higher corrosion rates because, you know, corrosion is universal truth. You cannot avoid corrosion in totality. So, because of this operation regime change, you will see higher corrosion rates. So, people are going for some additional measurement to find corrosion products like using turbidity and other measurements. So, there are a lot of other measurements also coming in a picture which earlier were not so critical because you were working on a steady state. But at the same time, now I would say you will see more real-time importance of these measurements because I remember earlier plant is operating on a few hundred megahertz steady load. Even everything is steady. pH is also steady. Dissolved oxygen is maintained. But as you will deviate from it, you will see disturbances in even these parameters. You know, to restore condition, you have very less time. So, you need to actually go for some good technology for adopting these measurements and use them in a daily life. So, you will see change in operation the way people are operating plants also.
ANANT
That's actually right because if at an equipment level, the more carefully you actually maintain the equipment, the better time, the better efficiencies, all of that you'll get. And you've given an in-depth analysis of what all different parameters are responsible for it, what should be the corrective actions and so on and so forth. So, thank you. Thank you very much. Any last thoughts for our viewers in terms of what they can do in terms of improving performance at their specific plants?
ADITYA
So, I would say today, water chemistry, you know, till date was like slightly ignorant area. You have something which is going in parallel. So, you're operating plant your way. There are some alarms and set points you are taking care. But chemistry is going in its own way, you know, because it's done manually. Sometimes you have only some deviations you need to take care. But now, even integration of water chemistry measurements into daily operation is going to be very, very critical for all users. Wherever you're using steam and water as a utility, everywhere you will see more and more importance to these type of issues and monitoring. So, just see how you can have a robust, reliable measurement in place so that you can actually go for controls and future corrective actions as you go along.
ANANT
Right. So, even the awareness needs to be improved in that context in a way.
ADITYA
So, as I mentioned, in large power plants, awareness is good. But still small power users, small captive boiler users, they were not bothered about this kind of issues much. But this kind of issues can lead to permanent loss of efficiency, outages and also sometime some catastrophic failure of pressure parts, which can be avoided and we can change scenario in industry.
ANANT
Yeah. So, in terms of not only performance and uptime, but also from the perspective of safety, water chemistry becomes a very, very critical element. And it's good to see that it is becoming more and more mainstream. That awareness is increasing, but there is still some distance to go. Yeah, sure. Yeah. So, thank you. Thank you, Aditya, for your time. Just to summarise this for our audience, we talked in depth with respect to, there is a certain amount of awareness gap with respect to water chemistry parameters going into steam and condensate loop systems. The awareness is improving, but there is still a considerable amount to go. We need to be aware of different water chemistry parameters that are important to measure, such as pH, such as conductivity, such as dissolved oxygen, such as turbidity, and each of them will have a different impact on the system performance. So, unlike the olden days, today the water chemistry parameters are dynamic in accordance with the dynamic nature of the plant operation itself. And as a result, it becomes that much more important for the users, the operators of these particular plants, to ensure that these parameters are carefully monitored, that any deviation in their performance are captured, insights derived from that, and those insights are then communicated for effective corrective action, which will ensure not only a good efficiency as well as a good uptime, but it will be critical from the perspective of safety for steam and condensate loops like this. Additionally, going forward, we see a lot of digital technologies coming into the picture, and as a result, collecting all of this data, because historical data is considerably voluminous in terms of its availability. So, collecting all of this data and feeding it to a digital technology tool can give us better parameters, but only if the water chemistry channel is aligned with the other KPI channels of a particular plant. So, from that perspective, it is very, very important for people, for operators, for engineers, for supervisors, and plant heads also to be very aware of what different chemistry parameters they need to look out for. So, the awareness part is very, very important, and we recommend that you find more information about this. You learn more about this, educate yourself. If you need any help from us, please reach out to us, and subscribe to the Fobs Marshall YouTube channel for content similar to this, and look out for the FM Energise podcast upcoming episodes. Thank you.