Global Cement and Concrete - Review 2011

2nd Global Cement and Concrete Conference and Exhibition 2011
22-23 March 2011, Jeddah, Saudi Arabia

A review by conference convenor Dr Robert McCaffrey

Image gallery for the Global Cement Arabia Conference 2011

The second Global Cement and Concrete Conference and Exhibition Saudi Arabia has successfully taken place in Jeddah, Saudi Arabia, on 22-23 March 2011, with 22 papers, 30 exhibitors and around 200 registered delegates. The conference was co-sponsored by both the Arab Union for Cement and Building Materials and by Saudi Readymix, the largest concrete company in the Middle East.

The conference started with a welcome by conference convenor Dr Robert McCaffrey, who mentioned that Saudi Arabia has around US$23.5 trillion of proven recoverable oil in the ground (at $100/barrel) and that 38% of the population of Saudi Arabia is under 15 years of age. Those are two statistics that show that – whatever happens in the Middle East over the next 50 years – Saudi Arabia is probably the most robust long-term cement and construction market in the world.

The first technical paper was given by Abdullah Sarhan of the National Committee for Clean Development Mechanism (CDM). The CDM concept encourages CO2-efficient projects in non-Kyoto Protocol countries, and allocates the projects CO2 certificates which can be traded or sold. CDM projects have to comply with the condition of 'Additionality' in that reductions in emissions must be in addtional to any that would occur in the absence of the project. Potential projects must be registered before they start and can be certified for three periods of seven years, or for one period of ten years. Nuclear, avoided deforestation and geological storage are excluded from the scheme. Mr Sarhan suggested that the 13 cement companies in Saudi Arabia, with a current 49Mt of cement production capacity, could apply a number of different CO2-reduction strategies, including fuel switching, waste heat recovery and the usage of slag and fly ash in cement and concrete blends. He pointed out that around 35% of the energy consumed by a cement plant is vented as flue gas with a temperature of above 300°C – a perfect energy source.

In the Concrete technologies session, Sultan Faden, head of the founding group of the Saudi Green Building Council, spoke about 'Green building and concrete in Saudi Arabia,' giving as a prime example the King Abdullah University of Science and Technology. The project was the first LEED project to be classed as 'Platinum' in Saudi Arabia, even though 470,000m2 of the project was completed in less than two years.

Redwan Hameed, Technical Director of Saudi Readymix, next gave a well-received presentation on self-compacting concrete. He pointed out that good quality concrete requires good workmanship, including good compaction, to get rid of entrapped air. This makes the concrete stronger and more durable. For example, decreasing the amount of entrained air in concrete by 1% increases its strength by around 5%, partly due to the increased bond between the concrete and the rebar. Compaction is usually achieved using poker vibrators, but this can be difficult in big pours and in practice a significant proportion of each pour may remain uncompacted, while some structures cannot be manually compacted, such as walls and pilings. In addition there may not be enough workers, vibrators or vibrators of the right size on a job, or the rebar may be 'congested.'

As Redwan Hameed demonstrated, self-compacting concrete (SCC) is a highly-flowable non-segregating mix which spreads into place, even around congested rebar. SCC reduces man-power, makes pumping and placing easier and leads to a better surface finish, with no repair work required, while improving the bond strength with the rebar. SCC is manufactured from OPC I cement, fly ash (<5µm, 13,000 Blaine), silica fume, coarse and fine aggregates, 'sweet' water and a polycarboxylate-based HRWRA superplasticiser. Despite its superior performance, SCC has come up against resistance from the market for a number of reasons, including that actual results on the job site can be different from laboratory trials, inconsistency of raw materials (including due to varying set times and product fineness of cement), pumping effects and due to the risk-aversion and conservative outlook of specifiers. Mr Hameed underlined the point that education and awareness are important to grow the market for SCC. It is also important to maintain strict quality control and to modify and optimise the mix throughout the project.

The 'processing technologies' session at the conference started off with a presentation on energy-efficient kiln seals delivered by Anis Haider of ITECA. He pointed out that seals are critical to the efficiency of a cement plant, since false air reduces production and increases specific energy consumption. The larger the gap, the greater the money that will be lost. The ITECA system uses 'auto-lubricating' graphite blocks which tightly hug the kiln using counter-weights. The blocks have a lifetime of 4-7 years, with an expected wear rate of 3-5mm per year. Air can be blown into the casing of the blocks to cool them and Mr Haider claimed that the system leads to 'no leakage.'

Lars Seneberg Nielsen of Hasle Refractories next detailed the five critical areas for refractories and how to solve them. The five areas are burner pipes, the nose ring, the smoke chamber, the bull nose and the tertiary air damper. Hasle Refractories has both pre-cast and castable refractory solutions for all of these problem areas.

The popular 'maintenance' session of the conference started with Konrad Meyr of Elogic GmbH, a German company which is very active in the field of filtration in Saudi Arabia. Given that environmental legislation is becoming continually more stringent in the Kingdom, Elogic advocates doing as much as is necessary (to comply with the regulations) but as little as is possible. Konrad Meyr pointed out that his company's solutions for filtration might be more expensive to buy than some competitors, but that they include a 'real' warranty, improved emissions, supervision and lower shut-down costs.

ZK Zarif next spoke on behalf of American company Vezer's PIC on how to optimise corrective contractor work. Given that maintenance backlogs are now common throughout the industry due to the recent recession, many companies are bringing in contractors to try to complete the jobs. ZK emphasised that continuous evaluation of contractors is important, and that it is important to work out what is the 'right job' and then to do it right first time. He concluded that if your preventative maintenance regime continues unaltered but that the number of 'emergencies' increases, then your preventative maintenance regime is not working!

The final presentation of the day was given by Karl Haugen of Haugen System AB, which compared spillage management by investment in vacuum technology with outsourcing the function to a vacuum contractor. Karl pointed out that "Every European cement factory has a vacuum cleaning soltuion, either in-house or contracted-out. Of all the dust lost from a plant, 90% goes up the chimney but 10% is retained in the plant: this is valuable material which can be collected and sold and which might total perhaps 10,000t/year – or US$400,000 in value. Mr Haugen claimed that his mobile vacuum truck is capable of paying back its investment cost within a year and that it then has a lifespan of 15-20 years. Continuous cleaning can be used to establish the dustiest areas in a plant and can also help with prioritisation of maintenance.

The day concluded with a sumptuous banquet enjoyed by the assembled delegates, before they drifted off into the perfumed Jeddah night.

The second day of the conference started with a session on grinding and was kicked off by Dr Jürgen Brand with a presentation on the installation by Mertec of a 600t/d double shaft lime kiln at Ras Al Khaimah Lime Co. As Dr Brand stated, "In the year 2008 the Ras Al Khaimah Lime Comp. (NOORA) decided to increase its production capacity significantly by around 200,000t/y of burnt lime. The MERTEC technology group, with its headquarters in Switzerland, won the tender for the erection of a double shaft kiln with a capacity of 600t/d complete with materials handling, transport, storage and packing systems as a complete turn-key-project. The scope of supply included the screening and transport of the limestone to a new concrete silo, the transport from the silo via another screening station to the kiln, the double shaft kiln itself (executed in close cooperation with the Maerz company) with all auxiliary equipments necessary and the complete quick lime transport to a new big bag loading station – one of the largest big-bag loading stations in the world, capable of packaging 1t/minute. The erection was done in co-operation with the Mertec Middle East Maintenance Unit, based in Ras Al Khaimah, and other local companies. The site for the material handling systems was opened by end of 2009, the works for the kiln started in March 2010 and the successful commissioning took place in the middle of October 2010. All guaranteed values have been fulfilled by the project."

Next in the grinding session was a presentation by Stefan Seemann of reknowned German engineering company KHD Humboldt Wedag, seen right. Stefan pointed out that KHD is currently 'getting closer' to its customers by establishing customer service centres in India, Asia-Pacific, the Americas, 'EMEA' (Europe-Middle East-Africa) and 'Others' (including China). Dr Seemann surpised the audience with his assertion that the roller press is the most energy-efficient means of cement grinding, allowing a 2-4.5kWh/t saving over the next most efficient method, the vertical roller mill, and leading to approximately US$2m/year in electical energy savings for a 7000t/d cement plant. KHD's roller presses can be used for raw meal and cement: for very abrasive materials such as slag, the rollers can be coated with autogenous wear protection stud-lining, leading to life-spans of up to 18,000 hours. Stefan emphasised that an effective separator is required for efficient grinding and that some years ago KHD invented the V-Separator static separator for a low-energy coarse cut, but which also acts as a multi-functional separator, de-agglomerator and dryer. For maximum efficiency, a dynamic separator must also be used: KHD's COMFLEX arrangement now means that the whole system can be as small as only 30m high. The COMFLEX system comes in single, double and triple versions and leads to flexibility and high throughput.

Mamoon Yassin of Magotteaux then spoke about the use of XCC composite alloy for cooler plates, pointing out that a common problem with cooler plates is the increasing gap between, above and below the plates due to wear and non-alignment. Using XCC plates leads to much lower wear-rates, particularly in the intermediate and cold zones, with – according to Mr Yassin -typically 3.8 times the service life of XCC cooler plants. The Magotteaux 'pocket grate' design fills with clinker and means that – due to this autogenous wear protection – the air holes in the plate do not become worn, leading to 'easily a double lifetime.'

Continuing on with the theme of the session, Jose Esteves of Manvia, Portugal, spoke about his company's professional ball-sorting service. Mr Esteves suggested that practically all the multinational cement companies outsource their ball sorting to Manvia, at only 10-12% of the cost of buying new balls. Typically, the Manvia ball-sorting truck will be driven to the factory and the built-in trommel screen will be loaded with a Bobcat or front-end loader. The sorted balls will then be delivered to a series of big-bags attached to the side of the trailer, which can then be lifted with a fork-lift truck for reloading into the kiln. The truck only needs a source of electricity but with two-person operation can then process up to 8t of balls per hour.

The penultimate session at the conference was on 'Environment, fuels and pyroprocessing.' Bodo Guse of Pillard started the session by supplying details of a case study at Riyadh Cement, where, due to erratic supplies of crude oil, the company decided to convert its firing system to heavy fuel oil (HFO). Due to its much higher viscosity, HFO requires heating to enable it to flow. This means – even in a hot country like Saudi Arabia – the HFO must be heated by a separate thermal oil heating system and containers and pipes must be carefully insulated. Bodo mentioned that tankers need to be maintained at 50-60°C to ensure pumpability. A new suction heater needed to be installed at the company's tank farm, as well as new diesel-powered boilers which were used to heat the thermal oil to around 250°C, with a return temperature of 190°C. The cement company found that it had a similar consumption of HFO to crude oil, but that HFO (a by-product of petroleum refining) was only half the price of crude oil. The payback time for the conversion project was expected to be as short as 18 months.

Conference stalwart Georg Rathwallner of Evonik Fibres GmbH proceded to give a presentation on P84 filter media. Georg pointed out that the ID (induced-draft) fan typically makes up 60% of the cost of a filter installation, so that lower pressure drop in the filter can save a great deal of money. Modern needle-felts can achieve clean air with 'single digit' mg/m3 dust loads, can be stored for years, are thermally and chemically stable and can even be used as an alternative fuel at the end of their lifetime. He further pointed out that since the P84 scrim has a higher permeability than glass-fibre-based felts, it has lower emissions at a lower pressure drop. The longer filtration cycles with P85 filter fabrics also lead to lower consumption of compressed air and lower mechanical stress on filter components and bags.

The next presentation was given by Henrik Vittrup Pedersen of FLSmidth Airtech A/S. His message was that gas distribution inside the filter is important for filter efficiency. The use of screens in the filter to cause the dust to flow to the bottom of the filter can lead to direct collection of dust without it having to be collected on the filter bags, leading to a longer lifetime of the bags and fewer cleaning cycles. FLS's 'star cage' for bags means that the bags have less contact with the cage, while the fact that the bags are precision-made in the company's own factory means that they have a perfect fit to the cage, both factors leading to a longer bag life. The company's 'intelligent' cleaning sytem only cleans bags that need to be cleaned, leading to lower specific energy consumption.

The final paper in the 'pyro' session was given by Andreas Hand, again of KHD Humboldt Wedag. He emphasised the trend towards larger plants and low-NOx calciners operated under sub-stochiometic conditions (essentially a lack of O2). As an example of this trend he gave details of the four-string preheater at the 10,000t/day JP Himachal plant, which might have been yet larger had there not been a height limit on the preheater tower of 150m. He also pointed out that KHD can supply a number of types of innovative pyroprocessing equipment, including the Pyrostream burner – which can be adjusted using air-swirl channels - and the Pyrostep cooler for clinker quantities of up to 10,000t/day.

The final session at the conference concerned transportation and logistics, and was started by Firat Oezkan of Beumer Maschinenfabrik GmbH & Co. KG. Given that clinker can occasionally exit from the cooler at up to 180°C or higher, it is important that the clinker conveyor is as robust as possible. Firat reccommended the use of a Beumer belt-apron conveyor, which has garnered 119 references in the cement industry around the world. Savings compared to a chain conveyor derive from its lighter weight – so that less steel needs to be used in the civils - its higher conveying speed and its long service life. The air-gap between the belt and the carrying pan means that even with clinker at 600°C, the belt will effectively be insulated and will experience a maximum temperature of only 100°C.

Arturo Corella Monzon of CEFISA described his company's software approach to managing and optimising bulk, bagged and palletised bulk material production and dispatch.

The penultimate presentation at the conference was given by Sebahattin Akbas of Maschinenfabrik Mollers GmbH, where he described the company's palletless reverse hood packaging system, based on the use of stretch film. The system uses only 1kg of plastic to package 1t of cement, while the system creates a weatherproof package which is easily handled with a fork lift. The stretch film is also recyclable and the system means an end to the use of pallets for cement transport.

The last – but not the least – presentation at the conference was on high speed bag filling systems from Haver & Boecker. Claus Ohlmeyer started his presentation by saying "I'm very pleased to see so many of you here, even at the end of the conference," before describing the record-holding Haver Roto Classic. The new machines are more compact than before and fit the same number of spouts on a smaller diameter or more spouts on the same diameter. Due to the new compactness, it is now even possible to apply ultrasonic sealing to a machine with 16 spouts, while at the same time making the machines easier to maintain. Claus said that everyday maintenance is typically now twice as fast as before. The new machines open up fantastic possibilities for busy cement plants, which was illustrated by Claus Ohlmeyer using a photo of four Roto Packers being used to supply eight automatic truck loading stations.

Following the conclusion of the presentation programme at the event, delegates were invited to relax at the Farewell Party, where the Mertec-KHD stand was awarded the 'best exhibition stand award.' After counting up the delegate votes, Karl Haugen of Haugen System AB was awarded third place in the best presentation award, while second place went to Clause Ohlmeyer of Haver & Boecker. However the award for best presentation went to Redwan Hameed of Saudi Readymix for his very popular and informative presentation on self-compacting concrete.

The multinational audience – from more than 20 countries – then dispersed to the four corners of the world, many saying 'See you next time at the Global Cement Conference in Saudi Arabia – Inshallah!'