Login

High efficiency cement cooling for cement milling: Nick Sutherland, Solex Thermal Science Inc (Canada)

Filmed at Cemtech MEA 2015, 8-11 February, Grand Hyatt Dubai, UAE

Already a subscriber? Login

Subscribe to get access to all News, Articles and Video sections of the CemNet.com website.

Subscribe

Just a little bit of background before I start on the presentation, I'll just flick on to the agenda, I'm just talk over that. This is a paper which is based on a pilot study that we did in Canada, Lafarge's Exshaw plant of the [xx] rocky mountains. We don't yet have a full surge unit in operation, it's still sort of early days. But we are hoping in the next few months to secure orders for one or two units around the world. So, if you bear that in mind when we come to the questions.

Some of this information is actually coming from Lafarge Exshaw, I did this as a joint paper with Red Ambary who is the Process Developer Manager at Lafarge Exshaw. So, he added some of the background to it. So, why do we need a cool cement? There's lots of reasons, there's current demand from the customer for tighter and tighter cement controls is the problem it potentially causes you in the silos for blockages.

So, we know cement is a hydroscopic product, it will absorb moisture from the atmosphere if it's temperatures are not in balance. Maybe not so apparent at the moment but I remember the good days when you could sell every ton of clinker you could make or turn it into cement. So, a lot of the problems with feed going straight from the kiln or the cooler straight to the cement mill with no possibility of cooling in between. So, quality a few reasons for the cement cooling trends. I'll skip through to one or two of the slides just to give you some background. Obviously, I don't want to teach you the cement industry, I'm sure you all know where a cement cooler sits. And this is the conventional technology if a cement plant actually needs a cooler at all. And this type of unit, as we know as a cascading water fall down on the outside and then the product being driven up through the middle.

Couple of photographs to the line these are actually from Exshaw, even when you put a [xx] around it over period of time it turns into a cement blanket and when it comes to do the repairs it's a really pain to get rid off. I got a picture on the top, the amount of build up you can incur their.

So, the customer being Lafarge so the [xx] down a few issues that causes blockage into the drains because the cement gets into the water, it goes down to the drains and it starts to build up and it causes floods, it causes all sorts of problems. I'm sure you know all the issues that you have with traditional cement type coolers. After you've been running for a while you start to loose the efficiency because the water attracts only a part of the surface you know if you've lost surface area, if you lost the cooling capacity.

So, a quick look at our technology, this technology has been around for about 25 years, but only in recent times have we looked at cement as an application for our technology. This particular example is actually cooling sand. So, this is actually a two bank units, fed from the top, this is coming from a sound drier and then cooled through our unit through a mass flow core and now though a rotary valve.

And this is sort of a representation of what's actually inside there, sort of heat exchanging plates with water going through indirectly transfer from the product to the plate into the water and then taken away through the water flow. So, these are the two things the two technologies are in competition.

One thing that our technologies scores very highly on is energy usage because apart from the rotary valve which is controlling the flow rate and maybe an elevator to get it into the unit itself. If that's required, there's no energy import, we use gravity which is free. So, a brief history of the industry or of the technology.

So, it was about 25 years ago that it was developed. It was developed by a fertilizer company in Canada that was also a mining company [xx]. We've actually achieved over 450 now, we're about 500 units worldwide on all sorts of different applications, from things as diverse as a breadcrumb cooler in the UK which she's keeping the breadcrumb sort of almost chilled before it goes into making sausages. Now, there is one end of the spectrum, the other end is a plant in United States that's cooling carbon, blackened graphite from 2000 degrees C, yeah I said 2000 degrees C using out technology.

Okay, there is a certain amount of re-fracture lining, water jacketing to actually control that but we put the unit in and it's been very successful. So, basically any product that looks or resembles those along the bottom be it polymers, seeds, sugar, chemicals, bio solids, grains, all sorts of products, provided it has free flowing properties and will fall through our units, we can handle it.

A little bit out of date, we've just recently moved offices but I like to keep this one in because we own the office and we used to lease a little bit out to Lafarge, just a nice little addition. So, we're based out of Canada in Calgary just at the foot of, well about an hour drive east from the rocky mountains. And as you can expect we've got contact agents and sales offices around the world.

So, being based in the U. K and covering Middle East among other countries. So what is the technology? What's the principle of operation? It combines two things and that's mass flow and an indirectly heat transfer. So, you have the products falling by gravity between the plates and then you have water in the sandwich of the plate in turbulence flow extracting the heat, taking the heat out of the product. So, no contact between the product and water.

Okay, the next line is a short animated video of the way it operates. So, hopefully this time it works. So you see the product falling in from the top, fills up the units, level control inside the inlet hopper, controls the feed-out of the units and discharge. That can be whatever the suitable discharge here is, whatever your rotary valve, [xx] feeder, vibrating feeder.

You see here the material falling between the plates and water in turbulent flow going through the plates. So cooling water is coming at the bottom and then coming out at the top. So, it's in a counter current direction which we find is the most efficient. This next part of the video I bolted on is just to walk around the 3D model of it, just to give you an idea of what it looks like.

So in this case it's a single bank, top parts is inlet hopper, bottom part is the discharge feeder as I say that controls the residence time. Because there is no moving parts, it's virtually maintenance free, you've got a few access points where you can inspect. The only real maintenance required is the occasional cleaning, particularly if you get upset conditions, abstrain of the operation, maybe you put too much water sprain in your cement mill and you actually get water in the cement itself.

With designing units we've complete full size doors for every bank, so not just for cleaning but should you have an eventuality where you have a damaged plate and you need to remove it. Unlike normal heat exchanges you can remove that one plate and continue running, or you can leave it in and just blank it off. On the back here the manifold's each plate has got a separate flexible manifold outside, connected outside of the flow of cement, so there's no possibility of contamination. See it's just an access point to the bottom, it will then just strip away the casing and show you how simple it is.

It's just a series of heat exchanger plates inside of a casing and material is allowed to cascade between. Now, it's a modular design, so should you increase capacity, it's as simple as building another module and bolting it on top. And as we use gravity that just increases the residence time, so you basically can increase the production throttle.

Very small foot print, so for retro fit into existing factory, you don't need a lot of floor space. It can be quite easily installed. All you need is a vertical space. What will the plates look like? They are actually lazer welded and dimpled and the way they are manufactured is, they are lazer welded around the outside, baffles are welded in between to actually get turbulent flow and then you've got these circular welds here, where the plate it starts as a flat plate and then it's inflated to 40 bar and it actually forms this like pillow shape. If any of you have been to the stand I've got a couple of bits of sample plate where you can what it actually looks and feels like, and that creates all these multi channels which gives a really good heat transfer across the floor surface.

As you can imagine we work in a lot of industries from the breadcrumbs right through to potash maybe solar evaporated potash from the dead sea is something in that line, where the fluid is very high in chlorides. We have to use titanium grade seven or something. For cement we would stick with three or four stainless for the plates and the outlet device and carbon steel for the casing was just no real need to go exotic on it.

I will not get through all these slides, is basically screen dump of the software. As you can imagine the knowledge and the expertise is like a [xx] these days is shocked into a software program. So, we can do the modelling of any product, any cooler, any temperature and we can tell you exactly what the exact temperature, with any part of the cooler across the section of it or from top to bottom.

This is just, on the right it just shows the temperature profile as it comes in between the plates unless [xx] cement this is maybe 40 millimeter spacing. The product is constant temperature and as it drops through between the plates you get a temperature profile always at the greater effect of the surface of the plate and a lesser effect to the center. With that in mind, when we get to larger units, multi-bank units, say two or three banks, the banks are actually are offset so the plates are actually offset which give almost like a mixing zone which is improves the efficiency. And this graph shows a three bank unit, the water is obviously coming at the bottom and it is heating up as it goes through and the product is cooling down as it drops through. And then you can see this red graph which is showing you the the temperature as measured at the plate.

So, you can see how it jumps at the transition zone as the hot product hits the cold plates and vice versa. One thing we sort of pride ourselves on is taken a lot of time to understand the product. With so many diverse products we really need to understand all the characteristics of it. In particular the flow ability that is the key to the success of our technology.

So, we always request a sample of we take to our laboratory, we do extensive testing through a flow model to establish the optimum plates placing because we don't want to be too wide. The unit becomes too large, it needs to be an optimum spacing between the plates. We'll also look at both density, we'll do our own fill of conductivity measuring so that we measure the sample as in both condition so inclusive of the voids and nothing but the aspects.

That's exactly how our units will see it. Specific heat, angle of repose, particle size, flow-ability, sheer cell, if it's a problem particularly difficult to handle. And we have learnt over the years that things don't always work. We tried to video a cement sample in the laboratory. You can just see the product moving and that's in real time.

It is very difficult because cement is grey and the background is grey, you may say 50 shades of grey, that was a joke. We put some polystyrene balls on the top to trying and give it some contrast, because without that you would hardly see where the product stopped and started. But to give you a better idea, so that cement being tested to give you a better idea, this is a mine potash going through the unit. It's a lot easier to see is the granular form so you can see it better. You can actually look at the sort of speed that the product going through between the plates. The reason I like to include this little video is normally we get people questioning the reliability, and life of the plates and they say with cement or potash or sand you're going to wear those plates out in minutes.

Not true, it doesn't matter how abrasive the product is, if there is no kinetic energy you don't get the attrition. So we found this is moving so slowly that it doesn't actually wear at all. One or two customers, that use it on the sand have insisted we put like caps on top of the plates. They are really not required, [xx] keep the sand level in the hopper of both the plates and don't let it hit in contact what it's feeling you are okay.

So, onto the pilot test, we see some data about the mill and what we actually carried out. It was a close circuit mill capacity about 130 tonne an hour, it was producing type one general cement. The mill outlet temperature as measured was 97 degrees and the cool inlet temperature because these plants had two traditional coolers already in place. So, we measure the outlet of the milk and also the inlet of the cooler, so you can see there's a certain amount of cooling takes place, just in the air flow through the cyclones, the thermo separator etc.

And they where trying to achieve a 45 degree cement outlet temperature. Our pilot unit which is basically a baby sort of scaled down version, we plugged it in under process conditions, we ran cement through it and then returned it back into the system. We were running it 115, 150 and 250 kilos an hour. Okay, that's not a lot but it was a small unit with water going through it, and we were cooling from 80 to 40. It was a little bit higher than the cooler inlet temperature because we stubbed into it, slightly further back up the line, and was achieving 40 degrees outlets quite easily without a challenge.

This is a few photographs of the set up. So this was the main feed pipe which was going to the two coolers and that was after the filters, the back house, the [xx] filters, everything was connected and then going into these two existing coolers. So, we just stabbed into above it, put a valve in as our inlet hopper. There's the actual cooling bank of cooling plates.

You've got a discharge cone here, and a rotary valve. And we even had an aerated cone in case we had problem with getting the product to move. Although we used it, we didn't need it we can use a plain wedge to wedge mass flow count. We even left it overnight, so we left it sort of from 6 PM in the evening, came back about at 10 AM the next morning, left fuller cement overnight, we turn on the rotary valve and it flowed right out.

No problems, no build up, no blockage. Even I was surprised at that. So here's a quick look at the sort of a typical schematic and G8 design, as most cement plants install two coolers. It's traditional that there's always two I guess one is, they're probably designed to be 60% of the capacity each. So you got a bit of capacity [xx] together and if you lose one you can still put cement through the other one.

So, we looked a comparable design using 265 tonne coolers with a target of 7045. It would be a two bank units, a control device from the top controlling the outlets device and then a water control module to control the amounts of water and the temperature of that water going into the unit. And then that could be all interlink to the cement plant existing DCS system and this is roughly what it looks like in a 3D drawing about 12 meters top to bottom, two meters square foot print and two banks.

And then a wedge to wedge mass flow count. It was a comparison of the old technology with the new. This is the existing tube cooler, this is our plate cooler, both on the same duty. Right through to the available water temperature, the difference came when we looked at the water usage. We can make more use of the water because it was a multi-pass through the heat exchanger plates and you can probably imagine controlling the amount of water cascading down the outside of a tube is not that not controllable really. So, we were a little less water usage, that was quite key for action because while they drew water from the river the environmental rules, we're saying that they were able to stop that and they were able to use a close intel water circuits and they were looking for a close loop system.

So this meant less water usage through the system, and I look at the power, each of the vertical traditional coolers have 90 kilowatt motors on them and we estimated 22 kilowatt elevator would be sufficient to feed both coolers. So, quick talk about the general design advantages. It's a compact installation, so it lends itself very easily for retrofit. It's a modular design so you can build for any future expansion. You got full access bank doors for cleaning purposes and maintainance, I'll also say there's zero maintenance on these.

And you get slow and control movement of the product, it doesn't degrade the product, not really critical for cement, but similar sugar industry they don't want any abrasion or any degradation of the production as it goes through, and it's got a high stable performance. Just one or two photographs of the unit from the static, this is the access store, these are just cones that keep the plates spaced together, they're quite easily removable to replace the plates.

Well that's more for access to clean them, should you need to and cleaning is, cement, you can probably just allow low pressure air in the fertilizer and then to it can get very chocked and sticky. They use [xx] but maybe that's not the right sort of thing in the cement industry. I think air would be more than sufficient. This is looking in the top of the hopper which shows you the plates spacing and then this is the actual connection of the manifolds to each individual plate where we use a flexible hose to accommodate any expansion and use a little bit of flexibility for the installation.

Okay, I'm getting towards the end now, no electrical power input apart from maybe if you go to [xx] or rotary valve but their fractional powers may be 2.2 kilowatts maximum, it's totally close, no dust emissions, no dust or water contact, it's low maintenance and low running cost, there's no bearings to grease and maintain, there's no lubrication to carry out, there's no ware parts to replace, you've got a lot control device from the hopper to keep the hopper filled, to control the outlet, and it can be easily interfaced with the UDCS system, giving a low life cycle cost solution, I talked about different discharge devices from a vibrating feeder to a hogan feeder this is similar to a vibrating feeder, but it's actually got [xx] as well, so you can damp material out very quickly, a gate discharge, circular feeder, I'm sure you are all familiar with this different technologies, what we are looking at for the cement industry is a rotary valve or a mass flow screw, which are both proven technology in the cement industry mention this module in design, and this sort of explains it, from a one bank two three four five, we've actually gone to five bank units in the and they sound cooling industries, very small footprint and you can use your fine space for this with an existing plant so a single banker unit five to seven meters to a full bank which is about 20 meters.

This few example projects, this is the one I showed earlier the Sun cooler, we also supplied a close loop cooling system, so they wanted mineralized water to avoid any corrosion, and it's circulated through the cooler, and then outside to some air blast coolers dry-coolers and then pump back into the system.

So that was sand in France, this is potassium sulphate in Belgium, [xx] of cement in terms of it's fineness, consistency and flow-ability. On this case it was a small units, so we actually use vibrating feed, I think that was in the drug chain. This is not a fertilizer application on ammonium phosphate in granular form again it was just pictures to give you an idea of what it looks like in the size of it within a typical building.

And I've just closed with a couple of slides because we're getting more and more enquiries as people start to realize this could be useful technology for energy recovery because we use water as the cooling medium. And now you can put it through a high temperature cooling application and potentially generate pressurized hot water which you can flash off into steam. It's possible we're looking at that with several companies at the moment particularly in the shell oil gas areas around Alberta in Canada. Here's an example of basically using off gas maybe from your cooler grade, 250 degrees Celsius, putting it through as an air as a medium into our unit and actually preheating a raw material. And then dumping gas back out through the stack. So, this is an air top unit, where you built this planet in shape it's almost side.

So there's an opportunity. I put these from other industries that I think may be apparent and relevant for the cement industry. Here's a little opportunity of putting hot product through and putting water through to actually cool it and generate pressured of water flashing off into stain then if you got a turbine or something you can use that stain.

I think that is the end thanks for your time.

Cemtech Europe 2024

Cemtech ASIA 2024

Cemtech MEA 2024

Cemtech Europe 2023

Cemtech Asia 2023

Cemtech MEA 2023

Cemtech Webinar 2022

Cemtech MEA 2022

Cemtech Americas 2021

Cemtech Asia 2021

Cemtech Webinar 2021

Cemtech Webinar 2020

Cemtech MEA 2021

Cemtech Virtual 2020

Cemtech Europe 2019

Cemtech Asia 2019

Cemtech MEA 2019

Cemtech Europe 2018

Cemtech Asia 2018

Cemtech MEA 2018

Cemtech Europe 2017

Cemtech Asia 2017

Cemtech MEA 2017

Cemtech Europe 2016

Cemtech Asia 2016

Cemtech MEA 2016

Cemtech Americas 2015

Cemtech Europe 2015

Cemtech Asia 2015

Cemtech MEA 2015

Cemtech Europe 2014

Cemtech MEA 2014

Cemtech Europe 2013

Cemtech Asia 2013

Cemtech Jakarta 2012

Cemtech MEA 2013

Cemtech Geneva 2012

Cemtech MEA 2012

Cemtech Europe 2011

Cemtech Europe 2010

Cemtech Middle East 2010

Cemtech Europe 2009

Cemtech Dubai 2009

Cemtech Florida 2008

Cemtech London 2008

Cemtech Singapore 2008

Cemtech Dubai 2008

Cemtech Florida 2007

Cemtech Prague 2007

Cemtech Abu Dhabi 2007

cemtech florida 2006

Cemtech Rome 2006

Cemtech Barcelona 2005