4th Global Fuels Conference 2010
26-27 May, Washington DC, USA
The 4th Global Alternative Fuels Conference for cement and lime took place at the end of May in Washington DC, a few blocks away from the White House and a short jog from the US Capitol building, heart of America’s governmental process. The conference was co-sponsored by the US Portland Cement Association, and attracted representatives from practically all US cement producers, as well as a number of Mexican, Central American, Canadian and international producers as well. A large number of lime companies were also represented at the event, from North America and abroad.
Dr Tyrone Wilson of the PCA started the conference with an explanation of the current state of legislation in the US for alternative fuels (AF). In essence, the US Environmental Protection Agency (EPA) has been asked to update the regulations. At the start of the process, the EPA seemed to be positive about the possibility of burning AF in cement kilns, and appeared ready to apply a ‘light touch’ approach. However, when the draft regulations were published at the start of May 2010, it was apparent that a significant change of heart had occurred and the EPA now seems likely to apply stringent emissions regulations (rules that currently only apply to industrial incineration facilities) to cement plants. The cement industry is not happy about this possibility, since it would certainly increase its costs and might potentially lead to the closure of a number of US cement plants. The PCA and other industry representatives are now very busy trying to make the EPA see that by making it harder for the cement industry to use AF, the materials are likely just to end up in landfill, which is not a particularly good way of protecting the environment. The final regulations are due to be published before the end of 2010.
Following on from Ty Wilson was industry stalwart Michael Blumenthal of the Rubber Manufacturers’ Association. He pointed out that tyres are currently viewed as a waste, unless significant processing steps are undertaken to create a specified product, such as reduced-metal chipped tyres. However, under the proposed new EPA rules, if the raw material is a waste, then it will remain a waste and the cement kiln user will have to be regulated under the onerous incinerator rules. Michael stated that once the new rules have been published, they will be immediately challenged by either the environmental lobby (for being too lax), or the cement industry (for being too harsh) or possibly both (for being too harsh and too lax at the same time). A final decision is not expected before 2014, but the cement industry hopes for a ‘business as usual’ scenario in the meantime.
Rob Davies of IPP (see right, making a point) next surveyed the landscape of AF technology for the cement industry (and some of the factors that influence usage). He gave details of wind, solar, mechanical-biological treatment (MBT), anaerobic digestion, algae-based fuel, gasification and pyrolysis, the use of engineered fuels, bio-solids and pellet and cube fuels. Rob concluded that the US has a very long way to go to catch up with the Europeans in the area of AF use and resource conservation.
Next up was an eye-opening presentation on the concept of landfill mining, by US firm Schreiber, Yonley and Associates. The company says that it can be done - and can provide fuels for cement production - but that there are a number of hurdles that would have to be cleared even before starting to dig. The most significant regulatory requirements are those under the Resource Conservation and Recovery Act and those under the Clean Air Act. After gaining your permits to dig (no small matter), landfill mining would consist of resource definition (as with any mine) through drilling or by using geophysical exploration, probably accelerated methane production, excavation, separation, possible beneficiation of separated fractions, stockpiling and dispatch. The economics of the process are critical and no two landfills are the same.
Rahim Vaseghi of the Islamic Azad University of Iran was the next speaker and detailed the unusual situation in Iran with regards to AF. Since the Islamic Revolution in 1979, the government has effectively subsidised the cost of energy for both domestic and industrial consumers (alongside a number of other commodities, including bread, making Tehran one of the cheapest capital cities to live in anywhere in the world). However, due to an economic crisis and ongoing budget deficit, the government has been forced to drop its subsidy, so that industry will go from paying next-to-nothing for its energy to having to pay ‘top dollar.’ The 70Mt of cement production capacity in Iran (which is now comparable in size to America’s own domestic industry) is now very actively looking at the possibility of using AF. However, also in common with America, there is little compunction not to just put waste in a big hole in the desert. One way or another, the Iranian AF industry is about to be born.
Following these global, regional and national studies, the conference turned to look at more technical subjects. John Tiernan and Hyder Busheri of AFS Technology firstly gave an interesting paper on the use of suspension burning for tyres. Suspension forks in the precalcining chamber are used to hold the tyres in the gas flow, where they combust without adding to NOx and where the tyres’ influence on the sulphur cycle can be minimised. The technique appears to have promise for future development and industrial application.
Stefan Laux and Jeff Moscari of Praxair next detailed the benefits of using oxygen-enhanced combustion for AF. Without doubt, the approach is of great economic benefit in sold-out markets, where the use of AF can be increased with minimal reduction in production (or production can be increased in the absence of AF). If markets are not sold-out, then the use of oxygen enhanced combustion may be marginal or sub-economic, but the markets will become sold-out again, and then oxygen will be back.
David Lahaie of Evergreen Recycling then gave details of an anaerobic digestion process for pulp mill residuals and dairy waste that could provide not only methane as a burner fuel but also a solid (de-watered) fuel for use in cement kilns.
ABB’s Eduardo Gallestey then went on to explain how ‘Advanced Process Control’ not only stabilises the pyroprocessing system, but also allows the increased use of AF.
Gala Dinner and Global Fuels Awards
The Gala Dinner at the conference took place at the historic Anderson House of the Society of the Cincinnati, an opulent mansion in Washington that many of the delegates present at the conference had no idea even existed. After the dinner, the Global Fuels Awards took place, having been nominated by conference delegates. Lehigh Cement’s Union Bridge plant was awarded the ‘Alternative fuels project of the year,’ for its hard-fought-for bio-solids project. Cadence Environmental Technology was awarded the ‘Most innovative technology for alternative Fuels’ prize for its Mixing Air technology and process. Cemex was given a special prize for ‘Best electrical energy project’ for its new EURUS wind power project, while the ‘Alternative fuel company of the year’ award went to Vexor for its VEF - Vexor Engineered Fuel. The Global Fuels ‘Personality of the year’ prize was awarded to Michael Blumenthal of the Rubber Manufacturers’ Association, who, during his long career in rubber, has been responsible for - literally - moving mountains (of tyres) into cement kilns. A funky soul band entertained delegates late into the sultry night.
Second day
Early next morning, presenters from Vexor and Schnarre Engineering recounted their experiences with testing an engineered fuel (VEF) in kilns and calciners. VEF has a number of benefits and advantages over coal and its use is growing in the cement industry. Vexor points out that it would be useful to have a national AF pre-qualification system, so that an AF tested in one state would automatically be qualified for use in all other states (which is not the case at the moment).
Luc Rieffel of Walter Materials then gave details of two of its AF projects, one at Lafarge and one with Holcim. Both involved storage, handling and dosage and they both demonstrated the company’s wide capabilities in AF processing.
Loubana El Atasi of Napier University, Scotland, then spoke about Taiheiyo Cement’s use of recycling waste as alternative fuels in Japan. The company has been using alternative fuels for nearly a decade and accepts a very wide variety of materials, including shredded pachinko machines (pachinko is a kind of Japanese vertical pinball). The company also uses an ash-washing process to remove chlorides from municipal incinerator bottom ash, so that it can be used as a raw material for cement manufacture.
Well-known engineering company IKN USA was next up, to speak about the optimum means of AF use in a number of case studies. Lengthening the residence time of AF particles, to ensure complete burnout and to reduce NOx, is critical and can be accomplished with the adaptation or construction of a separate calcining chamber, or by other means.
Peter Windmoeller of Vecoplan detailed a case study of AF preparation and storage at a North American cement plant. The company’s storage facility has an inherent homogenisation function and the AF thus produced has a steadying effect on kiln conditions (and can thus increase clinker production capacity) at the same time as using AF: a win-win situation.
The hazards of using AF were pointed out by Jörg Baldauf of Thorwesten Vent GmbH: as well as self-ignition behaviours, AF can give rise to explosive atmospheres that must be planned-for. His company’s explosion venting doors and explosion and fire prevention systems are acknowledged as among the best in their field.
John O’Brien’s presentation on behalf of Plattco Corporation concentrated on the crucial considerations when selecting valves for AF projects, specifically Plattco’s double-flap airlock valves. John showed that these valves are very well-engineered and should be a strong contender for any project feeding whole tyres into the riser duct.
Continuing the theme of AF handling, Michael Gramling of WTW Engineering detailed his company’s AF solutions, including the sweeping auger for discharge of AF, the truck docking station, chain conveyors and an active bottom discharger for AF, as well as giving information on AF projects in Poland and Ireland.
Thane Browning of Aumund partnered with Dennis Odom of Holcim to present a number of different handling options for AF, including the use of the Samson surface feeder. The Samson feeder, which does not require costly excavations to install and can be easily moved around on site, has a storage capacity large enough to take a full lorry-load of AF and can be covered to provide protection from the elements and to reduce dust and odour.
Tom Lowes gave the next presentation on behalf of Cinar Ltd and co-author Gina Nance of GCC and gave a pugnacious argument for the use of Computational Fluid Dynamics (CFD) to help solve AF-related problems and to optimise proposed AF-related projects.
FLSmidth Inc. and FLSmidth Pfister next gave a joint presentation on experience in designing complete AF solutions to meet permitted limits. CFD was once again used to optimise particle trajectories and burnout times, in order to decrease NOx production, and details were given of an AF project at Finnsementti at Lappeenranta, in Finland.
Ed Le, originally from Vietnam but now residing in Texas, next spoke on behalf of Cadence. Ed drew the audience’s attention to the possibility of using the fuel-lean gas-reburn method to reduce NOx production, by burning traditional fuels such as gas or oil in the oxidising zone at the back of the kiln, rather than using SNCR. Ed suggested that under many economic scenarios, the fuel-lean gas-reburn method can be cheaper to use and at least as effective as SNCR.
The penultimate paper in the programme was given by Jonathan Forinton of A TEC America, who spoke about techniques for the production of engineered AF, as well as the final destination of trace elements in the pyroprocessing system, including the most topical element of the moment, mercury. His conclusion was that mercury enters the pyro-system as a trace element in fuels and raw materials (including in batteries, thermometers, electronics and light bulbs in MSW). A small portion of Hg is absorbed into the clinker, but the majority is volatilised and circulates in internal cycles until it is emitted. The main strategy to reduce Hg emissions must be to reduce inputs, including separating out sources of mercury from MSW before combustion.
The final presentation at the conference was given by Tom Box, who espoused the use of two state-of-the-art techniques (Ewan Technology and the Cooper Process) combined together to form the CEFCO process, which is said to be able to eliminate practically all pollutants and CO2 from flue gas. If it is ever proved to be commercially applicable, it might just change the world.
Awards and prize giving
At the post-conference farewell party a number of awards were presented. Vecoplan won the prize for best exhibition stand. Jörg Baldauf was adjudged to have given the third best presentation for his paper on explosion prevention and protection and Luc Rieffel the second best for his presentation on AF handling. However the winner of the ‘Best presentation award’ was Ed Le for his popular paper on the fuel-lean gas-reburn method, given in an inimitable style with great panache.
Field trip
Following the conference, around 35 delegates took part in a field trip to Lehigh Cement’s Union Bridge cement plant, to see the company’s new bio-solids handling, dosing and firing solutions (left). The bio-solids project took several years to come to fruition, having to pass over many regulatory hurdles and to pass through many permitting hoops. Delegates were delighted to be given full access to all parts of the plant.
Conclusion
The conference questionnaires revealed that the event was extremely popular with the delegates, and that they had found it to be of exceptional usefulness. The ratings for the conference were the highest for any of the Global Fuels conferences.
