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Alternative fuels: technology, performance and challenges: Dr Arif Bashir, DG Khan (Pakistan)

Filmed at Cemtech Asia 2015, 21-24 June, Grand Hyatt, Bangkok, Thailand

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Ladies and gentlemen, good afternoon. My today's topic is Technology Perfomance and challenges of using alternative fuels. In my presentation, I'll be giving you a brief on the Pakistan Cement Industry and introduction about DG Khan Cement and then the type of alternative fuels that we have been using and more importantly are some operation results I'd like to share with you and thereafter the challenges that we're facing and it's going to be a very interesting session. That I attended the presentation yesterday and today and realized that alot of people have alot of experience about alternative fuels so the challenges that I'm going to talk on, I'm sure that in question and answer sessions, we're going to talk in more detail.

For those who are not familiar with the Pakistan cement industry, here is a map showing Pakistan neighboring Afghanistan, Iran top with China and here we're sharing our boarder with India. All those red marks are indicating the location of cement plants in Pakistan, all in all we have 26 cement plants in operation, with a production capacity nearly 46 million tonnes per annum.

DG Khan Cement Company is located somewhere here with the production capacity of 7,000 tonnes from a single line and then we have second plant somewhere here with a total production capacity from two plants 6,700 tonnes a day. The third plant that we're going to put up here, is in the South near Arabian Sea.

We'll be having a production capacity of 8,500 tonnes clinker per day. As I said that in Pakistan we're operating 26 cement plants nearly 45 million tonnes of production capacity and last year the capacity utilization was close to 76.7% but I'm so glad to share with you that this year's situation is totally different and we're touching a capacity utilization figure of about 85%. With economic development in the country, political stability, the economy is transferring to the booming stage.

If you look at the market share in Pakistan then we have a market share of DG Khan Cement close to 11.3% with the top coming from Lucky Cement having 15.8% market share. As I said we have two production lines in operation in the center of the country and two production lines are giving us total 6,700 tonnes per day where we have installed conventional ranking cycle and that can produce 10.4 megawatt of electricity from waste heat recovery unit. In the second plant which is situated at Khairpur, we have got 7,000 tonnes per day clinker production and 8.6 megawatt is the power generation from a new technology called Kalina Cycle. All in all in our plants we have been able to successfully substitute about 30% of our power from the waste heat recovery units.

It's the plant which is at Khairpur and I'm going to present before you some operational results on this beautiful plant where we have substituted imported coal with a locally made alternative fuels coming from different sources. If you look at the cost breakup of last financial year ending June 2014, then the major cost input are coming from fuel which is nearly 39% and power which is nearly 20%. Now these were the two key areas where our group started working during past three years and successfully we have substituted the imported coal with locally made waste materials. All in all, we have been using over a period of time, 23 different kinds of waste materials coming from industrial waste, agriculture waste, municipal solid waste, tyre derived fuel and poultry waste.



On the industrial waste front, we are using
waste coming from textile industry, sugar industry, shoe industry, paper industry and in the agriculture sector we have been using wheat straw, rice husk and other waste materials. Now municipal solid waste is one that is generated in the cities and we have entered into a contract with Lahore Municipal Authority where we are getting about 1,000 tonnes of EM mixture everyday. Now from the the City of Lahore after processing this waste we take the RDF in finished form to our factory where complete equipment is installed for feeding and dosing to the consignor. Now for the tyre derived fuel we also installed state of the art equipment comprising the shredders and the iron ore removal equipment then feeding and dosing to the consignor and also we are using the poultry waste. These are the tyre chips that we are using, we have the capability to put the entire tyre into the shredder then converting into small pieces as six inches to eight inches size and then further shredding can bring it down to 15-20 millimeter.

We were attending here yesterday a presentation on the feeding of complete tyre to the kiln system but here the difference is that we are removing the steel wires from tyres and for that we have installed a complete set of equipment comprising another shredder that can remove steel wires from rubber. What we have so far experienced that about 15 to 20% of steel can be removed with this wire cleaning machine which is coming from Elgin of Denmark and that steel can be sold in the market as a scrap material at a much higher price compared to what we are paying for the purchase of tyres and it can definitely add to the profitability.

Very clean rubber pieces in the size range of 15 to 20 millimeter are then taken to the storage area and then from there after proper weighing, it is fed into the consignor for complete burning. We have a reducing lone consignor which is a large consignor, it has sufficient residence time for the tyre pieces to be burned in the consignor.

And we don't have any problem so far for the un-burned material going into the kiln as far as tyres are concerned. The second material that we are using quite in large quantity is poultry waste and this poultry waste is available in the close vicinity of our plant area. This photograph showing the mixed MSW which is segregated as it comes from the municipal authority, we segregate and for that a complete set of equipment has been installed in Lahore and in the next slides I'm going to show you different equipment's that we have installed in Lahore and we have the capability to process about 1,500 tonnes of MSW which is coming into our processing line in Lahore.

There's the first light that shows you the super chopper that takes the tyre pieces and takes into the shredding system and lets the conveying into the shredder and up to the shredder, the particle size is reduced to 15 or 20 millimeter and that shows the wire cleaning machine installation. Some of the wire is removed with the help of magnetic separator and you can see here the wire which is sticking to the top of the magnet and the clean is passed through the belt conveyor leading towards the storage area. Now even we clean with the magnet the wires still the rubber pieces contain about 2-3% of the wire material and this rubber content is then removed in another shredder making it down to 2-3 millimeter size. This is our plant showing the feeding arrangement after storing these different kinds of waste materials in the known quantity and known chemistry homogenization, we feed the material to the consignor floor where a proper weighing system is installed and it goes to the consignor burning area. The picture showing the incoming material from the municipality authority in Lahore, we have large concrete parts where this material is spread to remove some of the moisture which is as high as 35-40% in the incoming material and on these concrete beds this is spread for at least seven days, where about 10 to 15% moisture is removed before it is going into the shredding equipment. This picture shows a Vecoplan, a German shredder and we take the material which is organic and inorganic material coming from households into the shredding machine and the particle size is reduced down to 60 or 50 millimeter. It has an output production or production is 35-40 tonnes an hour. After size reduction it goes through this belt to another area which is the vibrating screen, before vibrating screen is the magnetic separator to remove the metallic parts and this metal parts which are not in large quantity can be sold in the market on scrap rate. After passing through the magnetic separator, it goes to the vibrating screen area where you can see that vibrating screen is in operation and organic materials containing alot of minerals passes through this screen less than 50 millimeter size and that is taken out as a mineral or organic waste material.

The combustible material passes onto this belt and moves on to the next area which is called a Wind Sifter. Here we introduce air with a blower, and lighter particles are then taken away, whereas heavy particles some of the debris and stones, are removed from the bottom and those are taken out. Once a clean combustible material having good calorific value is passed through the wind sifter is taken to the bailing unit, here we see the wind sifter unit dropping down the material onto these conveyor that takes the material to the bailing unit. Now this bailing unit forms the bails automatically and large bails are then loaded onto the truck and taken to the factory where we have the burning facilities. For my presentation, I've shown you the TDF preparation, the MSWRDF preparation and the poultry waste that is available in the local area.

Now, for the results I've selected today, a coal combination of 70% with 10% MSW, 10% poultry waste and TDF 10%. So I'm going to present before you a comparison when we were using 100% of coal which is imported from South Africa. The operation results suggest that we have so far achieved 50% substitution in the consignor of the imported coal.

50% substitution in the consignor means, that overall we have achieved about 30% of the coal substitution from the cement manufacturing process. There's no production loss and that's very important finding. On the kiln size 7,000 tonnes per day with the large consignor, we don't experience any air stack emissions which are more than the permissible limits. The ID fan however, has a caution and we increase it by 1.5% because of the moisture content which is present in the MSW or RDF.

There is slight reduction in the trycrush insiligate but it does not affect the overall compressing strength of cement that we have observed over a period of three months. Though slight increase we have observed in the total alkali content, in particular in potassium oxide content and pre-lime is less than the permissible limit but there's slight increase in the pre-lime content as well.

Of course there is more tendency of quoting formation in cyclones and end ducts. Those who are sitting here coming from the cement industry must realize this, that alot of money we are spending on the refactories while we're going for the maintenance of the plants. So, this is an important finding of our research, that how this alternative fuel is going to affect the refactories and what are we going to remove those obstacles which reduces the financial profits.

Savings overall, we have experienced over a period of time between 20-25% in comparison to conventional imported coal. These are all attractive results but also we are facing a number of challenges. To start with high moisture content as I said 35 - 40%, inconsistent quality of RDF because it's collected from different zones and different areas and people have different eating habits and that is reflected when we receive MSW coming from different areas. Some debris, some chlorides once it contains some PVC material the chloride is a challenge. Ball formation in the the kiln and the coating indicate cyanide and cyclones that we have experienced over a period of time. Another challenge is the removal and disposal of organic waste, just to give you an idea that from hundred tons of MSW that we receive, it's nearly 60 tonne is the BTL which is organic waste and it has to be disposed off and then defect on the refectories. So these are the challenges that we have been facing and how we are affecting those challenges is quite interesting to see.

For the moisture content, as you're all very well aware, it increases the transport costs, high weigh rate of the shredders, high fuel consumption in the consignor and there'll be high power consumption as well because the ID fan is increased to 1.5%. Then the residents time of kiln consignor can be one of the challenges if the moisture content is high.

Some of the ideas that we put forward to remove this, to reduce the moisture content was, improving the sun drying on the concrete parts and that has improved significantly between 10- 15% moisture was removed because we have very hot weather in the Indian subcontinent, Pakistan-India. So we take full benefit of those five months when the temperature is quite high.

The second innovative idea was to have a drying unit to dry the MSW having higher moisture content and this drier was designed locally and we have been operating it with the help of burning some RDF and utilizing the waste heat which is coming out from the cooler area. It's partially successful in a sense that we've been able to reduce the moisture content further down to about 10%.

The other challenge is the removal of debris, grass, non-porous metals and mineral matter and that we've been able to do with a second stage screening, where we have installed a rotary screen with a 30 millimeter opening size and that is remove these debris and glass materials quite significantly. The organic waste as I said is still a challenge because we've got minerals and organic which can go to the landfill area, but we don't have the sufficient space of enabling the landfill area, so we need to do something with this organic waste to convert it into a profit center and to convert this organic business into profit center, we are now thinking of putting up a minting generation plant and a power generation plant which will be from the organic waste. This is the organic waste which is segregated after removing the combustible RDF. Just to give you an idea that how to do this organic waste and convert into useful product, that we have already done the receiving of RDF, preparation, removal of the and un-burned or debris and then the organic waste we're now thinking of putting up this digestor to generate biogas and from this biogas on the available scale that we have today, we'll be perhaps producing close to seven megawatt of electricity.

The total solids which are present in the organic waste material will be able to produce about seven megawatts of electricity. Then the remaining faction which is the residue after producing the biogas will be taken out into the composting unit and that we're going to do in this second phase.

All in all from the incoming material of MSW, we'll be using inorganic combustible material and a substitute for the coal, the organic material will be converted into biogas and the residue will be used as a compost material. So that's our outlook and that's our future planning. One of the area that I touched upon was the coating in the consignor and in the cyclone and the next slides I'm going to show you the type of coating that we're experiencing and then we have carried out extensive research on the chemical analysis of this coating that contains mostly potassium chloride and oxides of nitrogen. How to remove that or how to adjust our raw material chemistry and to introduce a coal having high sulphur content so that the alkalies come out as clinker as alkaline sulfates, that's what we have been doing and we are quite successful in doing that and removing these alkalies through clinker.

If someone bought material containing high moisture content and threw into the kiln, then it creates alot of unstable coating and boulder formation is there, those who are running cement plants must be aware of ball formation and the boulder formation. As a result of this ball and boulder formation and the excessive coating inside the kiln in different zones, the life of the factory is affected badly, both of the alumni and the magnesium brakes.

I can show you some of the inside pictures of the kiln and can see alot of coating all around the kiln. It reduces the part and then you can also see a ball which is coming here its a large size ball, which is coming to the clinker and enters into the cooler and creates all sorts of problem and choking of the crusher.

This is the size of ball I was talking about. Another view of the re-factory you can see excessive coating and some of these falling on bricks you can see here. We also noticed that there is a tendency of shell kiln, if we are using excessive alternative fuel and then there. So what we have done so far, we have carried out an extensive study of the entire kiln which is 5.6 meter in diameter and 66 meters in length, meter by meter we have taken the samples of bricks and the coating and that extensive study is showing the areas where spoiling takes place in the brick.

So these are the challenges that we have been facing today and with the adjustment of raw material chemistry and the coal, we have been able to reduce the effect of spoiling but it's not eliminated 100%. Another view of excessive coating OK, right because Keith asked me you tried to finish at least so that you leave some time for the questions.

If I may go up to the conclusion straight away despite various challenges in terms of processing and use of alternative fuels still it makes economic sense if proper makes his design to substitute imported coal and that's all about our work that we have been doing but in coming months we're sure that we'll be having more knowledge about biogas generation and composting plant, thank you very much.

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