5th Global Fuels Conference 2011
12-13 April, Kuala Lumpur, Malaysia
Conference review by Robert McCaffrey, conference convenor
Image gallery for the 5th Global Fuels Conference 2011
The 5th Global Fuels Conference for cement and lime has successfully taken place in Kuala Lumpur, Malaysia, on 12-13 April, with around 100 delegates from 20 countries in attendance, 50% of whom were cement and lime producers. The 6th Global Fuels Conference for alternative fuels for cement and lime will take place in Aachen, Germany, in 2012.
The 5th Global Fuels Conference for cement and lime took place at the five-star Sheraton Imperial hotel in Kuala Lumpur, a short distance from the spectacular Petronas Towers, formerly the tallest buildings in the world. The conference was opened by the event's convenor, Dr Robert McCaffrey, who outlined possible future trends in alternative fuels around the world. In the US, despite the continuing focus on cost-cutting, the permitting regime and well-meaning but misguided environmentalist lobbying have combined to make the increased use of alternative fuels (AF) very difficult if not impossible - much to the detriment both of the cement industry and the environment. Europe is well-recognised as having a great deal of experience with AF and continues to push the boundaries of what is possible in this area - partly by demonstrating that AF leads to lower overall emissions. The Middle East - due to its energy-wealth - seems not to be enthusiastic about AF. However Iran, despite its oil reserves, is now starting to become serious about using more AF, largely due to the elimination of fuel subsidies by the government. South east Asia currently has low AF fuel use but will use more as expertise is transferred, while it seems certain that China will become one of the leading users of AF in its cement industry, over a very short time-span and certainly within the next decade. Due to competition with other industries, the cement industry is destined to become more like a waste-processing industry, in order to provide itself with fuels based on domestic waste, a trend that has already been witnessed in a number of countries around the world.
Jan Theulen of HeidelbergCement (HC) went on to point out that - in his view - sustainability is the only way for a cement company to remain profitable in the long term. HC reduced its dust emissions (g/t clinker) by 35% between 2000 and 2008, while at the same time reducing its NOx emissions by 19% and its SOx emissions by 30%, partly by increasing its use of AF by 17% over the period. The company has a target of 22% thermal substitution rate (TRS) of AF by 2012 and 30% by 2020 (and a biomass rate of 6% and 9% respectively), by which means it will retain its place as the cement company with the highest TSR in the world. Europe already has high TRS rates, so that the majority of the improvements will come from changes in fuel mixes in Asia. Jan pointed out that fuels vary from region to region and he said that to successfully use AF in Asia it is important to have active people working on the ground - these are not schemes that are driven by the corporate office, but rather they become successful due to the commitment of local teams. Jan Theulen suggested that the cement industry is a service provider when it comes to waste usage, which requires a different mind-set from its normal role as cement producer. He pointed to a number of HC's AF projects in Asia, including a sewage sludge project for its plant in Guangzhou, China, which has saved around 25,000t of coal usage each year, a rice husk processing project in Indonesia which has led to a TSR rate of 20% and which saves 40,000t of coal each year and a mixed hazardous liquid waste, rice husk and sawdust project in the same country which can provide significant TSR at a feed rate of 10t/hour without deleterious impact on production, emissions or product quality.
Rezaul Karim next expostulated on the use of palm oil fuel ash (POFA) and rice husk ash (RHA) in cement blends due to their pozzolanic properties and pointed out that at low levels of substitution, they both increase the final compressive strength of mortar cubes and also increase sulphate resistance.
Alexander Koshi of PEG India was next up and forecast that the Indian cement industry would continue to grow through the period to 2014, largely due to India's 12th Five Year Plan, which specifies major infrastructure investment, especially in cement-intensive industrial zones and highways. However, largely due to unconstrained industry expansion over the last few years, profitability 'continues to be elusive' (despite the cartel-like behaviour of the cement market) and environmental regulations are becoming ever more stringent. Fuel costs make up around 29% of total costs for the industry and will tend to increase in the future, particularly after Coal India recently raised prices by 30%. A flight to increased AF use is all-but inevitable. India's population of 1.2bn people currently produces around 200,000t of waste each day, or 38Mt/year. At the present time, 95% of municipal waste is dumped in landfill (but not until all the valuable fractions such as metals, plastics and paper have been picked out by an entire caste of people). Alexander pointed out that as GDP grows in India, the valuable fraction of municipal solid waste (MSW) will probably increase while the inert fraction will decrease, potentially making MSW more attractive to the cement industry as AF. Needless to say, there is a huge potential use of AF in India.
Luc Rieffel of the ATS Group, part of Walter Materials Handling, next gave details of an AF project at SOCOCIM in Senegal, which used jatropha and groundnut residues as fuel, despite its 50% moisture content. A front-end loader was used to load around 10t/hour into a hopper and weighbelt feeder, which then fed into a pneumatic system that led to the main burner: a 40% TSR was achieved with the system. Another project at Siam Cement in Thailand used oil and sewage sludge, but two extra waste streams were also required - a fine stream consisting of powders and shredded plastic and a coarse stream composed of car headlamps and other bulky materials. The two new streams allowed an increase in TRS of 8%. A final case study at Holcim in the Philippines sought to use shredded rubber and plastic, while trying to minimise the introduction of false air in the system, through the use of a specially-designed double airlock valve featuring a cycle time of only six seconds and a counter-weight system to ensure full closure of each airlock. The practical details in the presentation were much appreciated by the assembled cement and lime producers.
A pair of presentations from FLS were next. Avinash Karrahe outlined FLSmidth's alternative fuels solutions, including the Hotdisc, the SLC-D downdraft calciner, Pfister Rotoscales for dosing, the Duoflex burner, a pipe-conveyor solution for AF and the OBA (oil burner atomiser) burner set. C.C. Leong of FLSmidth Pfister then gave further details of the company's feeding and dosing solutions for problematic alternative fuels. The FLS Pfister Rotor-weighfeeder is mounted on load cells and is much simpler than an equivlanet belt weighfeeder: it also measures actual weight, rather than density, is compact and is capable of handling both sludge and refuse-derived fuel (RDF). Mr Leong mentioned an AF project in Korea which used waste vinyl but which had been plagued with pneumatic conveyor blockages. Wood chips were added to the vinyl shreds, which absorbed moisture and made the combined material 'conveyable.'
Wai Chung Aw then gave a paper on behalf of Air Products, a company that uses oxygen to improve alternative fuel use. Mr Aw pointed out that AF often has a high moisture content and lower volatility which can reduce production when used with normal air (the nitrogen content of which absorbs heat and reduces flame temperatures). With an increased concentration of oxygen in the flame (and reduced nitrogen), flame stability and temperature are increased, available heat and heat transfer rates are increased and combustion efficiency is increased. CO and total hydrocarbon emissions are reduced and kilns are quicker to recover from temperature excursions. With the use of oxygen, a great variety of AF can be used - especially hard-to-burn materials or higher moisture materials - and oxygen can also be used to overcome ID fan or combustion air limitations. Production can be increased while product quality can be maintained, even while using AF. Depending on the fuel mix and the market conditions, payback can be as short as two months.
Matthias Mersmann of Aixergee next gave the assembled delegates an intriguing definition of AF: 'everything that burns that wasn't produced to be burned.' He went on to say that cement plants are normally designed to burn 'noble' fuels, but that AF can very from day to day, from season to season, from region to region and from country to country. There are many disadvantages to burning AF and all of them have to be addressed. Matthias pointed out that, against common belief, it is not always the case that primary air should be increased with the use of AF. In fact, it is important to understand the process to be able to design or to change the system to your needs: the final result should not necessarily be to maximise the TSR, but should be to arrive at the best (ie most profitable) economic situation (and highest TSR and greatest profitability are not necessarily achieved at the same level of AF use). Matthias concluded that to effectively burn AF, you should understand and optimise a number of different factors, including burnout times, flight residence times, flame shape, feed points and temperature and gas velocity distributions in the pyrprocessing system.
The final paper on the first day of the conference was given by Sebastian Devroe of Fives FCB. He described the company's low NOx precalciner, which is optimised for AF-firing and which reached 'zero-NOx' in 2005. Further research has allowed the system to be designed to achieve up to 70% TSR. In the company's D-NOx system, fuel residence time has been increased to achieve high burnout and low CO levels. Selective non-catalytic reaction (SNCR) ports can be tuned to meet NOx guarantees with low ammonia consumption. The design uses around 20% additional 'staging' or post-combustion air, which leads to a reduction in the NOx produced by the kiln.
Gala Dinner
On the evening of the first day of the conference, delegates were transported to the jungle setting of the Tamarind restaurant, high in the foothills surrounding Kuala Lumpur. After a pleasant meal, the Global Fuels awards were presented. Air Products was awarded the 'Technology of the year' award, and WTW Handling the award for 'Supplier of the year.' HeidelbergCement was awarded the Global Fuels 'Company of the year,' while Alexander Koshi was a popular winner of the Global Fuels 'Personality of the year' award. It was at the Gala Dinner that Aachen, Germany, was announced as the venue for the 2012 Global Fuels for cement and lime conference.
Second day
The first paper on the second day of the conference was given by Vincenzo Ferri of Italian company Cimprogetti. He mentioned that Italy's oldest lime company, the Zulian Lime Company, established in 1896, decided to build a greenfield lime plant and designed to be 100% fired with sawdust. A Cimprogetti twin-shaft regenerative kiln was used. Sawdust has a low heating value but also a low ash content (3% compared to up to 12% for some coals) and a moisture content of around 5%. A total of 36 burner lances are installed in each shaft to ensure uniform heat distribution. Since sawdust is considered to be CO2 neutral, the installation has resulted in a saving of 56,265t/year of CO2 compared to the use of coal. Mr Ferri went on to comment on his company's plans to use gasification of refuse-derived fuel (RDF) to create 'syngas' which would be used in place of natural gas. The characteristics of the syngas would depend on the RDF and the type of process used, but it would allow the maintenance of the quality of the final product while still consuming RDF.
Con Manias of FCT subsequently pointed out that there are dozens of different types of AF, all with differing characteristics. With this bewildering variety, FCT's approach to combustion design is to be thorough and systematic. For example, for a project at Turkey's Akçansa, FCT visited the plant and took measurements to determine the physical set-up of the pyroprocessing sytem, as well as determining all system constraints. FCT then modelled the system in a variety of ways including water-bead, alkali/acid modelling and CFD, before designing and optimising a new system that allowed the use of 100% petcoke through the main burner, up from a previous 30% maximum. The system also allowed production tonnages to be maintained while simultaneously providing a 10% increase in cement strength at 28 days. As Con pointed out, "Thorough mixing can be crucial for efficient combustion," while the lower calorific value (CV) and higher moisture content of AF can lead to lower peak flame temperatures and the subsequent reduction of process NOx. Con also mentioned his company's on-line continuous XRD mineral determination system, COSMA, which can be used to fine-tune the pyro-system towards greater efficiency.
Andrew Pal and his colleagues from Beta Analytic presented the company's methodology for determining the biomass component of alternative fuels via mass spectrometry of the carbon content of the fuel. Fossil fuels contain no C14, since it has a short half-life and practically none is left after 50,000 years. The determination of the biogentic component of AF is important, since non-fossil fuels can be removed from the greenhouse gas (GHG) emission inventory of a cement plant, and being biogenic do not require expensive emissions permits.
The penultimate paper at the conference was given by Wolfram Zschiesche of Vecoplan who presented case studies of AF reception, processing, handling, storage, reclaim and conveying. Wolfram went on to suggest that the future for AF in the cement industry would come with incoming AF being automatically allocated to different storage bins by a 'quality detector,' possibly on the basis of their moisture contents. These different quality fuels could then be blended (again automatically) to provide an homogenous fuel mix and consequent increased process stability.
The final paper at the conference was given by Vincent Grosskopf of Thorwesten Vent, who pointed out that AF brings many potential explosion and fire hazards to a cement plant, including the possibility of biodegradation and generation of highly explosive H2. Vincent pointed out that it is difficult to avoid explosion hazards and that therefore it is sensible to plan on how to handle them. He strongly suggested that explosion venting and self-reclosing vents should be fitted to AF silos to avoid any subsequent fire hazards after an explosion.
A final lively discussion session covered the importance of landfill costs and regulations in promoting the use of AF, the increasing costs of AF on the markets and methods to deal with blockages exacerbated by the increased alkali load consequent on AF usage.
At the farewell luncheon, the best exhibition stand award was given to ATS/WMH. Third place in the best presentation voting was taken by Jan Theulen of HeidelbergCement, while in second place was Matthias Mersmann of Aixergee. The winner of the best presentation award, as voted for by the delegates, was Con Manias for his paper on pyroprocess system optimisation.
Both exhibitors and delegates expressed their great satisfaction with the organisation and conduct of the event and all agreed that the choice of Aachen, Germany, for the 2012 Global Fuels Conference was an inspired location, given its central European location and strong links with the cement industry. We look forward to seeing you there!
