Global CemPower Conference and Exhibition 2012
14-15 June 2012, London, UK
Conference review - by Robert McCaffrey, conference convenor
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The 1st Global CemPower Conference and Exhibition on waste heat recovery in the cement and allied industries took place in London on 14-15 June 2012, at the historical Salters Hall – one of the birthplaces of the global chemical industry. 103 delegates from 25 countries attended the event. The 2nd Global CemPower Conference will take place on 4-5 June 2013, in London, UK.
As the first speaker at the Global CemPower Conference, Gill Ringland of SAMI spoke about scenarios for the future of renewable energy. Renewables will only slightly grow their share of the energy mix to 2030. Gill described three scenarios with varying economic growth, level of green values and level of technical innovation. New buildings in one scenario would be modularised, high tech, factory fabricated and include low employment. Smart grids, diversified energy sources and high use of renewables are suggested in other scenarios. Other scenarios suggest a continued emphasis on cheap and dirty fossil fuels, while a 'Deep Green' scenario, where a green society is achievable but only at the cost of economic growth, would be driven by a society which deeply values 'green values.' The audience was strongly in favour of a scenario with weak green values and moderate or strong growth.
Robert McCaffrey gave a listing of the seven megatrends that will shape the future of the global cement industry, including demographic trends (aging of both developing and developed nations), urbanisation (with 70-75% of humanity due to live in cities by 2050), the growth of new super-powers, the possibility of further climate change, paradigm shifts in the cement industry business model, ever-increasing energy costs and the influence of Rumsfeldian known- and unknown-unknowns.
Joe Harder gave a presentation on trends in waste heat recovery. Joe pointed out that the delta temperature of the system drives the energy recovery process, so that a heat sink must be present for cooling the working fluid - whether it is ambient air or for example sea water. WHR systems have higher efficiency with higher gas temperatures, but cannot achieve more than 40-50%. Potential increases in efficiency can be achieved by reducing heat losses, by increasing the heat source temperature, by decreasing the cold end temperature, using an appropriate working medium and by optimising the pressures in the system. The cement industry has a particular problem with WHR and that is the presence of dust in the hot gas. Despite this, larger cement plants can produce upwards of 45kWh/t of clinker (depending on the efficiency of the pyroprocessing system) and 15MWe in total. In the steam Rankine cycle (SRC), water at >250°C is used as the working fluid. In the organic Rankine cycle (ORC), a lower temperature can be used, down to 125°C. The Kalina cycle uses water and ammonia. Larger plants are of course more expensive, but have lower specific power generation costs. A typical payback period is from four years, depending on the local cost of electricity.
In the global cement industry there are already 520 WHR systems installed or under construction and 99% are conventional SRC systems. According to Dr Harder, Kawasaki Heavy Industries (KHI) is the world leader, then Sinoma EC, Nanjing Triumph, Dalian East and then JFE Engineering. The majority of WHR units are operating in China (more than 400 WHR plants) followed by Japan (23), India, Thailand, Pakistan, Turkey and the Philippines. Joe forecast that by the end of the decade, 1560 WHR systems will have been installed in the global cement industry, with orders dropping past the middle of the decade as all of China's plants are equipped with units. Joe suggested that ORC and Kalina systems will have a growing market share. A back-of-the-envelope calculation suggests that the total value of WHR system installed in the cement industry over the coming decade will be in the order of US$50bn.
Mark Mutter of JamCem Consultancy next gave a presentation on the comparative merits of Chinese and 'Western' cement plant projects (not specifically WHR units). He pointed out that he had no ulterior motives for his conclusions, and that there is obviously room for all suppliers in the industry, since they are all achieving significant orders. He pointed out that Chinese plant suppliers now have a 'history' and have proven their effectiveness. Technical developments have historically come from European manufacturers, but Chinese equipment manufacturers have achieved a significant global market share in a short time, largely based on lower cost (typically 25-30% lower than European costs). Chinese plants had positives and negatives, as with the European suppliers. Successful projects tended to have identified weaknesses in Chinese suppliers' offering, and to have taken appropriate measures (such as using well-defined contracts, improving documentation and training, having independent project management and making sure that all equipment is produced as specified). Mark suggested that the cost of these measures might total US$10m on a typical cement plant project. He suggested that a European plant might cost $174m, verses $140m for a Chinese plant, even including 'extras.' Net Present Value and Internal Rate of Return would be higher for a Chinese-built plant in a number of different scenarios, but not in all of them. Much debate followed.
Jay Narayama of PEC Consulting reviewed the factors that are critical to the applicability of a WHR project, and the factors that control which system is installed. Of the 830kCal/kg clinker of heat input, only about 230kCal is recoverable by a WHR system, and the rest is either not recoverable or is used in clinkerisation. Heat in the boiler exit gas is around 90kCal, so that only around 140kCal/kg clinker is useable by the WHR systems, with a conversion efficiency of perhaps 20%. Jay pointed out that generation of 1kWh of coal power generates about 1kg of CO2. WHR units offer a continuity of reliable supply, a fact which has a value of its own, particularly in isolated plants or plants with unreliable electricity supply. Long dry kilns offer good possibilities for WHR, while high moisture levels will reduce power output, since more energy will be required to dry the raw materials. Covered stockpiles are, in any case, a sensible move to reduce feed moisture levels. Jay stated that an economic WHR system must have low investment cost, low maintenance cost, high boiler efficiency, high efficiency of the thermodynamic cycle, a choice of optimised systems for specific conditions and a small footprint, particularly for retrofits. Economic viability depends on the waste gas conditions, the capacity of the WHR plant, the cost of electricity and other local factors. Typical installation costs are US$4-6m, depending on size, and the break-even electricity cost is calculated to be around US$0.10/kWh. Jay pointed out that the best approach is to try to minimise the amount of waste heat which is produced, and only then to try to generate electricity from it.
Mr Junichi Shobayashi of Kawasaki Heavy Industries spoke about the company's WHR systems. The company started its WHR business in the 1980s, and saw the division as a hybrid of its cement and power divisions. The company has built over 1000 waste heat recovery boilers in a variety of industries worldwide, based on the 'conservative but reliable' steam Rankine cycle. KHI offers a double or even a triple pressure system, if it is favourable for the client, and has optimised its systems to use low levels of water: the systems are also compatible with the use of alternative fuels in the cement pyro-process. 181 waste heat recovery plants have been built by KHI for the cement industry since its first project in 1982 for Taiheiyo Cement, with the majority (150) in China. In the last three years, 13 projects have been completed in Europe and Eastern Europe. KHI started its WHR business for the steel industry, but has found that the cement industry has dramatically increased its uptake of the technology in the last five years. The company has experience with a variety of effluent gases, with variations in dust concentration and dust characteristics. The KHI unit features vertical heat exchange tubes, with a hammering system to dislodge dust which is then recovered and reused. KHI's largest WHR system is for Sungshin Cement in South Korea, which will use waste heat from three kilns and which will produce 30.5MW. The company is currently installing a WHR plant in Turkey, for CIMSA Cement. KHI's WHR plants in China are now saving approximately $350m in electricity bills each year. Power output above guarantees and very high availability rates are also claimed for the systems. Mr Shobayashi concluded that the profitability of WHR generation will not be undermined by increased fuel costs in the future.
Li Hao from Sinoma Energy Conservation spoke about the Chinese cement industry and the development of WHR in China. Mr Li pointed out that increasingly sophisticated cement technology tends to lead to a lower effluent gas temperature, which can be expected to decrease yet further in the future. WHR systems have been applied to 58% of cement lines in China, around 800 lines according to Mr Li, but 18% of all lines are not suitable for the installation of WHR systems. Mr Li mentioned that by applying an air cooled condenser system, the water consumption can be reduced to 0.9t/ hr. Sinoma's system is designed not to increase the fuel consumption of the pyro system, and no tertiary air is used, so that before installation of the Sinoma EC system, the waste heat balance of the system as a whole must be optimised. Sinoma has designed, supplied and built 200 WHR plant around the world, with seven for Lafarge, three from Holcim and one each for HeidelbergCement and Cemex. Sinoma also offers the conventional steam Rankine cycle in its WHR units. A vertical boiler can rely on gravity, but a horizontal boiler must rely on a pump to drive water consumption, requiring its own electricity consumption. Single pressure, double pressure, flasher system and combined systems are all available for the cement industry. Sinoma's own Nantong Wanda Boiler Company is used to supply boilers for its WHR systems.
Miss Wang from Schneider Electric continued on to speak about her company's automation solutions for WHR with Sinoma, so-called Schneider Electric Ecostruxture, including EOS and remote access. The Energy Optimisation System, EOS, is a real time energy management and optimisation system for energy monitoring and analysis which allows optimisation of WHR unit operation. Remote access is made available using SCADA software, allowing remote monitoring and supply of advice, while KPIs can be visualised using a graphic 'dashboard.'
S.P. Ganeshan of Tecpro Systems, Chennai, India, next spoke about the status of WHR in India. Tecpro is a specialist in captive power plants, including those powered by coal, lignite, petcoke, gas and biomass, and also produces WHR plants for a variety of industries. The company has a collaboration with Nanjing Triumph Company, part of China’s CNBM, which has a 35% market share in China with 121 units installed, to supply WHR units to India. Tecpro has installed, or is installing, five WHR units in India, mainly dual pressure SRC units ranging from 4MW to 18MW. Tecpro supplied its first WHR system to Shree Cement and commissioned it only in May 2012, after only 13 months of construction, with a boiler from NTK, China. The design of the AQC boiler (air quenched cooler boiler) has been optimised by Tecpro, as have the structural characteristics of the PH (preheater) boiler and both horizontal and vertical boilers.
Ben Rankin of Evergreen Recycling gave a view of the cement industry from the point of view of North America. His company takes all sorts of wastes and transforms them into byproducts and products for other industries, including cement, steel, pulp and paper, smelters, foundries, automobiles and the semiconductor industry. The company offers both 'inside the fence' and 'across the fence' waste heat and waste organic energy solutions for industrial customers. Ben pointed out that the US cement industry produces around 70Mt of cement per year, but that many plants are small, with 80% of them being 'foreign-owned.' Plants have closed and others a closing due to cost inefficiencies, emissions regulations and active objectionable local citizenry. The typical delivered coal price is US$3 per gigajoule, with an electricity price of around US$0.06/kWh. Many plants are currently working at 60% capacity, but some kilns, for example in Florida, may be working at closer to 30%. Ben stated that hazardous fuels and waste oil are declining in use as an alternative fuel, but that bio-solids, refuse-derived fuels and woody biomass are all growing in significance for the cement industry. He stated that one major obstacle to the use of alternative fuels is the fact that there are few restrictions on landfilling, and where there are restrictions, the cost of landfilling is typically rather low, down to US$10/t. At the moment though, Florida seems to be the state that is most advanced in alternative fuels use.
Challenges to WHR use in the US include low electricity cost, low current run times and perceived technical challenges. He stated the perennial cement industry problem: "When the production rate is low, there is no money: When the production rate is high there is no time." However, there are growing economic, social and Federal governmental drivers that are leading towards greater WHR system use. Two states will subsidise up to 50% of the project cost, for projects less than 2MW, while utilities in one state offer US $1300/kW of installed capacity and 12 states include WHR in their renewable portfolio standards obligations for utilities, meaning that utilities may pay a premium for this WHR power in order to be able to meet their renewables mandates. Ben suggested that WHR systems are well-suited for third-party project development when a cement company does not consider electrical energy production as a core function. Many questions have to be answered before WHR becomes common in the US.
After a communal walk through the heart of historic London, a popular informal social evening took place at a Thames-side venue.
On the second day off the conference, Kevin Happ of FLSmidth introduced Tom Gibbons, who spoke about the Kalina cycle for use in the cement industry. He said that when choosing a technology to offer to the cement industry, FLSmidth decided not just to be another 'me too' steam Rankine cycle equipment supplier, but to offer the 'best' possible system to the cement and lime industry. "This is a fully realised system that has just been waiting for its day in the sun. You will see more FLSmidth Kalina systems coming on-stream in the near future,” said Kevin. DG Khan Cement's 8.6MW system is to be commissioned in 2012 and Star Cement in the UAE has contracted with FLSmidth for a 4.75MW system. Tom Gibbons, consultant, gave details of the Kalina cycle, which uses a binary working fluid of water and ammonia, the composition of which can be continuously varied through distillation and condensation within the system. This allows higher levels of efficiency of heat transfer than other WHR systems, up to around 50%, with the highest comparative gains coming at lower heat source temperatures. Tom mentioned a number of examples of the Kalina system in use on industries such as waste incineration, geothermal projects and solar hot water. He pointed out that there is no need to use special materials in a Kalina system compared to a Rankine cycle system. Tom did say that control of water quality is important, demineralising it to reduce sulphate, chloride and nitride ions, and deaerating it to reduce oxygen and other gaseous species, while also controlling pH, all just the same as in the Rankine cycle. Tom suggested that there is no evidence of nitriding of steels, even with the working fluid at a temperature of 465°C. Tom mentioned the possibility of corrosion by ammonium carbamate, but if CO2 is removed from the system, carbamates will not form. Stress Corrosion Cracking has not been seen in operating plants and low working temperatures and the high pH of the system also mitigate against this occurring. "It is important to treat the plant like any other power generation system with regards to the control of water quality," concluded Tom Gibbons.
Mark Boocock of Econotherm spoke about a technology that is not currently used in the cement industry, but certainly could be. Waste heat in the US represents 10% of all energy supplied by the US energy grid, or the equivalent generation of 400Mt of CO2. Mark suggested that barriers to WHR projects might include the aggressiveness of exhaust gas in terms of dust and chemical composition, the possibility of a WHR system interrupting the critical core process, and possible very long periods when it may not be possible to service the WHR system. Mark suggested that conventional waste heat recovery units may be vulnerable to thermal stress cracking, corrosion and wear. Econotherm's technology is based on thermal superconductors, which are 1000 times more thermally conductive than copper and which are now commonly used in exotic applications. Mark's company has developed an industrial version which involves the hot gas passing by the superconducting heat pipes, then other ends of which are used to heat water in a separate chamber. Each heat pipe operates independently, so that damage is not an issue, and they can be used in aggressive environments. The units are designed to be cleaned easily, either manually or automatically. The units can be used in lower temperature applications, have 'high efficiency,' have low pressure drop, and are modular and highly scalable. 80 units have been installed globally, including one in the gypsum industry. In this gypsum industry example, waste heat is recovered from the gypsum kettle, to provide preheated air back into the process. The gas was highly adhesive and had high particulate levels, while the low temperature of the gas required the unit to work close to the dew point. A horizontally-oriented heat pipe preheated was developed with transparent inspection windows to monitor any material build-ups and with individually replaceable heat pipes. The temperature of the exhaust gas was 135°C, with a 34 month payback. Mark also mentioned a case study in the ceramics industry, which had even more aggressive and problematic gases to deal with, for which Econotherm developed an automatic patented self-cleaning unit.
Riccardo Vescovo of Turboden, a company founded in 1980 to produce ORC turbogenerators and now part of Pratt & Whitney Power Systems, spoke about his company's solutions for the cement industry. Turboden offers standardised units up to 6MW, and customised units up to 15MW. The ORC system is a Rankine cycle which uses an organic working fluid for higher efficiency. An intermediate loop is used to transfer heat from the heat source to the working fluid, typically using thermal oil or pressurised water. This allows for ease of control of the system even with fluctuations in the primary heat source, as well as greater layout flexibility. Using a high molecular weight organic working fluid leads to a low enthalpy drop across the turbine, low turbine peripheral speed (with low mechanical stress and no reduction gear) a reduced number of turbine stages and high mass flow. The turbine efficiency can be greater than 80% and it retains good efficiency at part load. The organic fluids have no or low corrosion, leading to low maintenance requirements. No water is required for system operation. Turboden has three references in the cement industry. Ciments du Maroc operates a 2MW ORC system on a 5000t/d plant; Holcim commissioned a 4MW unit in Romania on a 4000t/d kiln in June 2012 and another unit in Slovakia, due for commissioning in 2013. Riccardo stated that is it very difficult to provide a straightforward rule to estimate the cost of a system, but the total might be in the region of Euro3000/kW installed, but up to Euro5000/kW. The economic results of a ORC WHR unit will depend on the cost of the unit, the cost of local electricity, the number of operating hours of the unit and the operation and maintenance cost for the unit. Payback time may range from three years in a best-case scenario, to eight years and beyond for more marginal projects. The numbers will change from project to project. Riccardo mentioned a WHR system installed on an electric arc furnace, which could recover 3-5% of the energy input of the furnace. He estimated that the amount of energy that could be recovered from the steel industry in Europe might be as high as 376MW, with around 145MW from cement and 107MW from the glass industry in Europe.
Nick Sutherland of Solex Thermal Science spoke about energy recovery opportunities in the mineral processing industries, including the cement industry. The company does not have any references in the cement industry, but continually receives queries from the industry, and is looking at the possibility of applying its technology for cement. The company started out by cooling fertilizers and now operates more than 450 coolers, heaters and dryers for all sorts of granular products. In the technology, product flows slowly by gravity between water-cooled plates, with the product flowing with uniform velocity in mass flow and the water flowing in counter current to the product. The amount of cooling or WHR is determined by the residence time of the water in the system. The modular design can be 'stacked' to increase capacity. Plates are laser welded and 'inflated' to create a quilt-like structure which can include baffles to increase turbulent flow and to increase heat transfer. The granularity and flow behaviour of the clinker would critically determine the effectiveness of the system in any cement plant application.
Giuseppe Bettella of Terruzzi-Fercalx Energy spoke about gasifiers for biomass, coke and coal. Through the acquisition of Vulcan Engineers of India, the company gained expertise in updraft gasification technology. Gasification is the substoichiometric conversion of a solid fuel into a synthetic gas, 'syngas.' His company couples the gasification plant with a rugged, fully automated biomass preconditioning system to ensure optimal drying and material characteristics. This syngas can be used for fuel in a kiln, can be used to generate combined heat and power (CHP) or can be used to generate power in an ORC system or internal combustion engine. Updraft gasification is more flexible and can treat a wider range of fuels than a downdraft system, including difficult-to-handle alternative fuels and a variety of biomass materials. The further the materials fall through the gasifier, the hotter they become, passing through a drying zone, then to a pyrolysis zone, then a reduction zone and finally through an oxidation zone. There is a counter flow of air and moisture/steam. Downdraft gasification tends to create a cleaner syngas, suitable for use in internal combustion engines for CHP. The technology can be combined with a briquetting plant, for easier material handling, and can be combined with a lime plant (or cement plant) to provide both syngas and fuel for the process.
Jan Theulen of HeidelbergCement spoke about the company's approach to sustainable energy: HC operates windmills and WHR already and is investigating biomass to electric projects as well as solar, hydro and geothermal energy. Jan stated that the potential for a biomass to energy project is high if a solid fee-in tariff exists. One project is on hold in Africa due to an unstable political situation. In another project, in Belgium, wood residue is used to create electricity and also to dry sewage sludge. The Lengfurt project was completed in 1999 and uses an ORC WHR system, while the Slite site in Sweden produces up to 6MW. Two projects have been completed in China, one in Guangzhou and one in Xian. The Canakkale plant in Turkey produced 15MW from two 6000t/day lines. Jan stated that (future) power prices, economies of scale, the investment level, the business model (100% investment or JV) and the sourcing of equipment are all strong contributors to the economic feasibility of a project. Jan stated that a WHR system made in China and installed in China can cost around Euro800/kW installed, 1000/kW installed in Asia and 1300-1800/kW if installed in Europe (again with equipment manufactured in China), based on a 5000t/d kiln with 3-4% moisture in the raw material. Jan stated that vertical and horizontal preheater boilers are equally reliable. HC has used NCDRI, Conch-Kawasaki and Sinoma EC Ltd as contractors for its WHR systems. Lessons learned include that you have to be able to specify the sub-suppliers for the main pieces of equipment, you need to be able to use a strong quality control process during the manufacturing process (having local representatives, having knowledge of which QC companies to trust, having time to check on the process yourself and also allowing time to allow for corrective measures). At Canakkale, there are two kilns, and a condensing flushing steam turbine with a 15.2MWe generator. Sinoma was the turnkey contractor. The total cost was US$24m, or US$1690/kW installed. Performance guarantees were achieved within four months of start-up. Problems included the fact that with a new kiln line the temperature in the cooler was higher than expected and the cooler intake point was too hot for the boiler, at above 500°C: temporary measures were taken to reduce the output of the WHR system, including the use of water sprays and the use of an extra cooler stack fan. Jan Theulen suggested that "Careful sourcing of qualified suppliers can considerably improve the payback ratio, while know-how transfer from supplier to operator is critical to the success of the project."
The final speaker at the conference was Eng. Muayad Matar, who spoke about the latest kiln line, the 7000t/day No. 3 line, and the new WHR system at Najran Cement Company of Saudi Arabia. He stated that oil is a precious resource, even in oil-rich Saudi Arabia, so that government policy is to reduce consumption of oil to the lowest levels possible: there is considerable pressure on Saudi companies towards energy efficiency. Holtec Consulting is the consultant for the project, while NESMA is the turnkey contractor with China Electronics Import and Export Company as the main subcontractor. Hazemag, Gebr. Pfeiffer, Claudius Peters, Ventomatic and Wartsila are the main European providers of equipment, with other equipment, around 30%, coming from China. The project should be completed in 2013. A WHR system with capacity of 27.1MW will be installed by Sinoma EC, the first WHR system in Saudi Arabia and the largest air-cooled WHR system in the global cement industry to date. Around 22% of the waste heat from the system is recoverable and will be used for power generation. Five PH boilers and three clinker cooler exhaust gas air quenching cooler (AQC) boilers will be used on the three kiln lines and two steam turbine generator sets. Net energy generation will be 165GWh per year, providing 34% of the cement plant's overall needs and reducing the plant's HFO consumption by 37,200t. Cost of power generation will be approximately US$0.07/kWh.
At the end of the conference, delegate votes for their favourite presentations were counted and prizes awarded. In third place was Junichi Shobayashi of KHI, while in second place was Riccardo Vescovo of Turboden. However, the winner of the best presentation award was Jan Theulen of HeidelbergCement for his ‘insider’s-view’ of waste heat recovery in the cement industry.
Delegates rated the conference very highly, particularly for its technical content and for its potential for networking. The 2nd Global CemPower Conference and Exhibition will take place 4-5 June 2013, once again in London, UK.
Delegates comments on Global CemPower 2012:
- Well organised, very focused conference: congratulations!
- My favourite thing was: networking and the meet the delegates session, the open and warm atmosphere and being able to meet everyone
- Very efficient organisation provided good value for money in such a short time
- There was a good balance of speakers/suppliers/technologies
- Well run – I appreciated the crisp moderation
- Congratulations – very well done
- Good conference
- The evening networking session was very nice
- I enjoyed the professional but relaxed atmosphere
- My favourite thing was the quality of the participants, the overall organisation, the location, catering… you name it!
- The conference covered a large range of subjects/perspectives on waste heat recovery
- Very high level of speakers and attendees with the right balance of technicians and decision makers.
- I like this subject-focussed conference, with a small group allowing better exchange of information
Global CemPower 2012 presentations made available by conference speakers:
Seven megatrends in the global cement industry, Robert McCaffrey, Global Cement
Trends in waste heat recovery in the global cement industry, Dr Joe Harder, OneStone Consulting
Turn waste heat into value: Dependable Turboden ORC solutions, Riccardo Vescovo, Turboden
Energy recovery opportunities in the minerals processing industry, Nick Sutherland, Solex Thermal