M.Sc. (New Brunswich), Ph.D.(B.C.)
- Rotary Kilns
- Steel ReHeating Furnaces
- Greenhouse Gas Issues
The objective of my research is to improve the processing of materials and encompasses traditional metallurgy; e.g. limestone calcination, reheating of steel, deoxidation of steel and emerging technologies such as biomass combustion and recycling of steelmaking slags. Quantitative understanding of complex processes is best achieved using mathematical models supported by experimental data. The application of this technology is within industry and several of the models have been placed in industry at BHP (Australia), ISCOR (South Africa), Northwest Mettech (Vancouver), Cerro Matoso (Colombia) and Hatch Associates and have been routinely used by operating and design groups. This technology transfer required both the development of user interfaces and inclusion of internal ‘rigour’ sufficient to reliably accept a wide range of operating conditions.
A summary of the key elements of the research is:
A rotary kiln model has been developed and applied to numerous industrial kilns processing a variety of materials. The model has been a key element in developing new business opportunies for Canadian consulting companies totalling ~$100 millio including the design of the 200 tonne per hour staged-combustion laterite pre-reduction kiln for Cerro Matoso (Colombia) The initial modelling work was awarded the 1991 Extractive Metallurgy Award by TMS and the CIM Light Metals Award, 1993 (co-authored). Model capabilities were significantly augmented by related work on modelling flow and segregation within the bed (Boateng, Ph.D., 1993, Dhanjal 2001) and fluid flow and combustion within the freeboard (Alyaser, Ph. D., 1998). The UBC pilot rotary kiln facility has been progressively upgraded and is frequently employed by industry for examining processing options, usually in conjunction with the mathematical model for scale-up. Based on pilot kiln work, both lignin (a waste product in the Kraft process paper mill) and BioOil obtained by flash pyroysis of wood waste have been shown to be a viable fuels for lime recovery kilns.
Steel Reheating Furnaces
Steady-state models were developed for pusher-type and walking-beam-type reheating furnaces and installed at BHP (Newcastle) for thebloom-mill walking-beam furnace and the merchant mill (pusher-type) furnace as well as at ISCOR for the pusher-type furnace serving the HSM. The W-B model was employed for the steady-state optimization of furnaces at AltaSteel and Manitoba Rolling Mills. The modelingwas enhanced in the mid-1990’s (Scholey, Ph.D., 1996) and an expert system developed (Mui, M.A.Sc., 1998) to assist furnace operators. A model for transient furnace operation was developed in collaboration with Slater Steel while, more recently a fast transient model has been developed for control applications (2003).
BioOil Combustion in the Rotary Lime Kiln (Dynamotive Technologies)
Dynamotive is a Vancouver-based company operating a pilot-scale (20 t/day) flash pyrolysis unit for producing a medium heating valueliquid fuel (under the tradename BioOil) from wood waste and is exploring marketing opportunities, particularly as a greenhouse-gas neutral fuel for the lime-mud kilns operating within the BC forest industry. A 14 month program on the UBC pilot rotarykiln generated a detailed assessment of woodwaste-derived BioOil as a fuel for the rotary lime kiln and also addressed peripheralissues such as fuel handling and atomization. Using natural gas as the baseline,BioOil was assessed on the basis of heat release profile, lime quality , energy consumption, off-gas volume and Nox emmisions. Scale-up to commercial kiln operations was made using the existing kiln model and indicate a small (5%) penalty in either energy consumption or off-gas volume (a limiting factor in many lime-mud kilns within the pulp and paper industry. Dynamotive is proceeding with commercialization of the process and has completed successful trials with Alcan.
Oxy-fuel Fired Rotary Scrap Melting Furnace
A continuous process for melting of steel scrap in an oyfuel-fired rotary furnace has been proposed by the applicant as an alternative to electric arc furnace. Preliminary mathematical modelling (Barr and Meadowcroft, 2002) suggest significant advantages in terms of energy consumption and environmental impact. Subsequent to this a pilot-scale furnace has been designed and constructed and has recently completed a full campaign of trials as part of an extensive experimental and modeling evaluation of the process (Zhang, PhD, 2007). As the initial modeling work had flagged the issue of heat transfer through the thin slag layer protecting the melt, this was examined experimentally in order to obtain more detailed data on the thermal resistance of oxide melts with induced stirring (Cao, M.A.Sc, 2005).
Greenhouse Gas Issues
Previous work has shown that by oxidation of the Fe component followed by quench cooling the cementitious properties of steelmaking slag can be enhanced sufficiently to make the ground clinker a viable additive to Portland cement clinker (Murphy, M.A.Sc 1997, Ionescu, Ph.D 1999). This technology has the potential to reduce CO2 emissions by the domestic cement industry by ~ 1 million tonnes/yr. Work is currently in progress with RWBlacktop for the complete redesign of the heater train for Hot Inplace Asphalt Recycling. This system will reduce CO2 emissions by up to 1000 tons per lane kilometer relative to repaving from hot-mix asphalt. Current work also includes development of a mathematical model for the Nexterra gasifier operation including validation against the pilot-plant operating data. This is viewd as a key element in the scale-up from the pilot gasifier.
- Y. Zhang, P.V. Barr and T.R. Meadowcroft; “Scrapmelting in a Continuous Process Melting Furnace: Bench-scale Furnace Trials” Ironmaking & Steelmaking, V35, No.8, 2008, pp 600-609
- Y. Zhang, P.V. Barr and T.R. Meadowcroft; “Scrapmelting in a Continuous Process Melting Furnace: Model Development of the Model”, Ironmaking & Steelmaking, V35, No.8, 2008, pp 610-620
- S. Dhanjal, P.V. Barr and A.P. Watkinson, “Heat Transfer in the Transverse Plane of the Rotary Kiln”, Metallurgical and Materials Transactions B, V35B, Dec.2004, pp 1059-1070
- Y. Zhang, P.V. Barr and T.R. Meadowcroft; “A Heat Transfer Model for Continuous Process Rotary Melting Furnace”, Pyromet2007, Falmouth, UK, May 3-6 2007
- Y-H. Li, A.P. Watkinson and P.V. Barr, “Firing of a Pilot Lime Kiln with BioOil”, Science in Thermal and Chemical Biomass Conversion, Paper No. Pb06, Victoria, August, 2004
- D. Ionescu, T.R. Meadowcroft and P.V. Barr,”Hydraulic Potential of High Iron Bearing Steel Slags”, Jornada de Investgacion de la Facultad de Ingenieria, Universida Central de Venezuela, Dec. 2004
- P.V. Barr, Y-H Li and A.P. Watkinson, “BioOil Firing for Industrial Kiln Operations, Proc.6’th Int. Symposium on Waste Processing and Recycling, COM 2004, Hamilton
- P.V. Barr, “Development and Application of a Fast Transient Model for the Billet Reheating Furnace”, Process Control and Optimization in the Non-Ferrous and Ferrous Industry (Invited), TMS/ ISS, Chicago, Nov. 2003.
- P.V. Barr and T.R. Meadowcroft, “A Rotary Furnace for Remelting of Steel Scrap”, Proc. XX Electric Furnace Conference, Nov. 2001.