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New bag house filtration for improved emission control – an Egyptian case study: Salvatore Gallo, Boldrocchi (Italy)

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

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Good afternoon, so today we're talking about a new bag house filtration technology we can see, to improve that's the mission control, and so some theory and some projects, where we realize this kind of design. Let's start to describe some Pulse Jet Bag Filter's principle to understand what are the main parameters that we have to take into account during the design of each filter that we realize.

So first of all, the first parameter, important parameter is the air to cloth ratio. It measures the velocity of the gas passing through the bag surface that we usually keep below one cubic meter per square meter. And second parameter is the can velocity, that is velocity of the gas, approaching gas from the bottom to the top approaching the free empty space among the bags.

And you can see, that can velocity parameter should be kept below 1.3 for kiln and raw mill and the clinker cooler integrated system and we have to take care to keep below one meter per second on the coal mill and bypass and cement mill. It can be, can be also varies. And the other two parameters are related to the inlet flange gas velocity to optimize distribution inside and the hopper flange velocity that it should be below the five meter per second.

Well, now we will explain how we found to improve the dust emission control and pollution control with our systems. So, we developed two key points. The first one is improving the optimization of the gas distribution inside the back filters and we will see how is possible to do it. And the second point we will see that we realised a special ventory system to optimise and say compress of their system.

So, first point we realize through the CFD simulation what the CFD simulation is the computation of through aerodynamics. So it's the process development inside distribution through 3D modelling and the assistant aided by the computer. And the three main steps, the three main stages which is for the executional, see if the simulation the first one is the three modeling design that means that we have to design in three dimensions the bag filter, the bag house casing, hopper and [xx] want to realize.

Second stage is the Iteration steps. Iteration steps means that we have to repeat and repeat the process distribution particles of gas and dusty gas inside the filters. To understand as you can see by red color, yellow coloring, velocity inside. So to take control about this distribution and then basing on the results that we got from the iteration step to apply modification architecture and modification on the filter.

This is to optimized distribution so that means that our filters are always tailor made design. So, each filter is checked by CFD simulation. Let's go in details about high dust bag filter technology. This is a picture showing our testing control room in our headquarter, Boldrocchi headquarter in Milan. You can see here that we're testing different length of specs starting from six to 12.

We have seen in the last years that many companies bag houses, company suppliers are fabricated and installing bags starting from 6-12 meters, for many reasons. For layout reasons, for dust reasons, etc., but as it's written here we can choose any length. But the importance is not the length that we use, but the importance is how much each bag works during the operation in the cycle, cleaning cycle because you can see that we can install bags 12 meter length. But if the gas is approaching part of these bags, it means that we are not using the full surface.

So, part of this surface is not needed and is useless, so money, cost and dust emission level not controlled as well and finally also compressing their system that is important, in new operation. So, how would it realize the optimization of distribution. The basic design of this filter model for high dust concentration is consisting in the double-feeding of the dusty gas through the bags.

So, the first part of the gas is going from the bottom to the top, as classic technology of the bag house filters and part of this gas is approaching the bags from this side. So as we said it means that part of the gas is approaching the bags on the bottom, so the bottoms of surface is used it and part of the gas is approaching from the sides, so even the upper part of this surface is used it.

We can start now a short movie of the CFD simulation as I shown before. So, you can see the gas approaching inside the bag filter, you can see the different color of that showing the velocity of the gas. And we will see in details, but now you can see that part of the gas is approaching from the bottom to the top, and part is approching by side, and then going out on the same outer flange.

So, this is the half filter section that we have seen. This is the gas inlet, starting, you can see through the buffles installed inside going out to the bottom part. Now here you can see the velocity is lower, and is approaching from the bottom and going up, and here you can see the part of this gas is diverted for side approach. So, the bags are used in the bottom by this part of dusty gas, and part of dusty gas is diverted through some deflectors you can see that we realize, for the side approach.

And the same you can see how the gas is going out here and part is going out here. This is the second key point, if you can see this is the CFD simulation of the compressor gas system, this is a section of the pipes of the blow pipes, each venturi installed is for each bag. You can see from the movie if we can show it again, you can see that this is velocity of the compressed air circuit completely in the venturi system.

This is to avoid some leakage of compressed air so it means that almost 100% is used to clean each bag. The result of course is to save, to have compressed air and less kilowatts power saved. So, we have seen there's a special venturi design that thanks to the design, thanks to the viscosity friction we can have almost 100 compressed air section into the venturi system for each bag.

So, let's see some results of this study. The first study we have seen the optimization of the distribution of gas inside. After we studied this technology, this distribution we found, 60% of the gas of the flow rate is going up to the top as we say classic technology, and 40% of this flow rate is from the side. So, this is to highlight how is important to use the full length of the bag.

So the advantages of this double side gas approach into the bags, through the bags and venturi design are, first of all less pressure drop through the filter, flange to flange measured. The results is power saving at the exhaust form of course. The 100% filtration surfaceworking, we can achieve low emission level and cost saving because we can install less filtration to face compared to the classic technology and longer bags life because in this case the berks can work properly in the full surface so that the backslide is longer.

And finally we have seen how less compress air consumption that means power saving for compressor. So, totally we can say this technology results is that low operation cost for the end user. This is the theory. Now, we go to the projects, how we executed this projects? One of the first filters installed with these technology is the one we finished the completion. Boldrocchi finished the completion in the 2013 so we collected all data and results during 2014. Now, we are here showing.

We are in Helwan Cement plant is Suez Company, part of Itel Cement. The company is located in Cairo, in Helwan close to Cairo. The plant of Helwan consisting two lines with total production 11, 000 tonnes per day. This copper works was the complete dismantling of existing ESP, both ESP for each lines.

Installation of new bag filters fans fand stack, old turn-key, mechanical, and electrical turn-key job. Some data about the gas flow. You can see the bag filters installed where 1.1 million cubic meter per hour and the dust inlet here is just below 300 grams normal cubic meter. This is first some pictures of installed in the completion phase.

The projects was part of Egyptian pollution apartment projects financed by the World Bank and we installed totally more than 5000 bags, length of each bag is eight meter. For a total filtration surface just below 20,000 square meter and the collected dust at the hoppers, the chain conveyor hoppers is 213,000 kilograms.

We installed bags with fiber glass with PTFE membrane and cages in carbon steel with cataphoresys special surface painting treatment. This picture shows how was the existing situation in Helwan. The first one was the original ESP and then upgraded in the 1997 with the second ESP in order to reduce the dust emission level, and then they decide to dismantle everything canned with the installation of the new back filters.

Well, here we can see how the theory and the process management works during the CFD simulation. We realize the 3D dimensional program, architectural modification inside the bag filters with baffle pipes and plates installed. This is to allow the gas to approach in a different way, and reduce the pressure drop.

And after the results, after we get the results from CFD, you can see here the that at the hopper, deflectors, pipes deflectors, and drilling holes to distribute homogeneously the gas inside there, the filter. And this is the really interesting approach we explained. We have installed some buffle plates on the central channel, the middle channel.

So this allow part of the gas approaching the bags even from side, from the side. So here, again is the theory and here you can see installed baffle plates to achieve the results that we are going to show. These are other pictures about the installation and showing all the plates, baffle plates to distribute.

You can see the central channel where the flow, the gas flow is going to entrance, and here you can see also some baffle plates going to the hopper and then approaching the bags from bottom to the top. Some pictures about lift and direction because this project was very critical in terms of time, realization time because the kiln shut down was very short. So, we pre-ascended everything on ground ground, and then we'll lift in three main pieces.

Only installation completed of insulation and everything. We will see also other pictures. Here you can see the casing, completely assembled casing in one lift we putting on the top of the hoppers. And here you can see, actually we're here on the, in the river empty river because we are in August. But the space was really, was very tight and the only possibility was to pre-assemble here on the banks of the river.

So also the project was very critical due to this reason. So, here the final assembly and the installation picture, all the complete erection and installation. We realised this installation without any modification on the existing concrete building. This is always to allow a shorter shut down of the kiln, and here are some numbers of this project.

The project schedule starting from the PO issue was 10 months for the first line, and the kiln shut down was 38 days. We installed totally steel and equipment, 1,740 tones and we involved two different companies with more than 130 workers for this job. And the biggest crane usage for the lift was 750 tonnes, so it's really a huge number for this kind of job of bag filters.

And let's, to show the most important numbers. So performances. The dust emission level measured one year after the first operation, so it means was October 2014. We guaranteed 10 milligrams per normal cubic meter and we measured below 5 milligrams or 4.8 per cubic meter. Pressure drop, total pressure drop guaranteed was 12 millibar and we found flange to flange 10.4 millibar. Compressed air consumption, we've seen below, we guaranteed below 187 normal cubic meter per hour.

And we measured with a flow meter at the compressed air station, 142. So, you can see how much we save this money and power with this numbers. And the power consumption at the fan because of good pressure drop of the filter. We guaranteed 980 kilowatts and we mentioned 870 kilowatts. So, we believe we are sure that this numbers are very important for end users.

Sometimes when big EBC contractors, we talked about this performances of course they are not so interested, you know, the prices, obvious. The most important aspect of the projects but the end users are usually looking to this because of custom energy now and power energy, this is really important to them.

This is just one slide to show that after the first project in Suez Helwan, we installed the technology, the same shape of filter in Hindenburg another plant. This is really really important, really interesting because as you can see the system was too fan system kiln and raw mill bag filter with 800 gram the normal cubic meter. And the results that we got from the customers are measured below one milligram per normal cubic meter, so the results has been really unbelievable.

If you need more clarification, more details and description about this you can visit our booth inside this conference. Let's very quick over view of the Boldrocchi group. Boldrocchi company was established more than 100 years ago, and with the core business manufacturing funds. The biggest factory in manufacturing funds is located in Milan and, but we have also workshops in India. In Chennai, Boldrocchi India for India market and the Brazil for the South Latin America market. And you can see also the ecologia division that air pollution control division, we're talking about where we're developing this bag house system. There are other division for other application like oil and gas, heat exchange, dampers etc.

that are not important here. The vision is the looping studying, working on fabric filters with high efficiency pulse jet filters as we have seen. But also electrostatic precipitators conversion from ESP into bag filter in the last years is really the usual to have these kinds of projects because of new regulations for the dust emission levels. High efficiency cyclones and multi-cyclones, gas conditioning tower and the gas reactors, SCR, SNSCR.

Not only for cement even for steel metal [xx] system. And this is the picture showing what I just described now. All kinds of funds manufactured in Italy, Kiln ID fund, Raw mill fund, coal mill fund, cement mill and everything, every kind of additional funds and all the bag filters, thus collecting system realized for the cement application in this case.

The important division, separated division of Boldrocchi Group, full dedicated to research and development. Every year our company is investing a lot of money on research and development because especially for technology of bag filtration, the gas filtration is very poor we say. It's nothing to invent but we have to research and develop to save cost, to allow customers to save money. So research and development is continuous is working for continuous improvement and this is the last light about our presence in the world. Since 1909 with more than 85, 000 orders delivered and more than 500 employers all around the world. We have a branch in India, in Egypt, in Brazil, Mexico, Germany and Milan and [xx] mostly, almost everywhere. So, this is some our contact address, you contact us with all the world wide presence, and with last born in Egypt during 2014. So, thank you very much.

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