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Many sugar mill boilers with baffled convection banks are susceptible to tube erosion failure. SRI has successfully reduced tube erosion at many sugar factories by redesigning convection banks using the CFD (Computational Fluid Dynamics) code FURNACE. In some cases where relatively small changes have been made to extend the life of a tube bank by a few years, a significant reduction in convection bank heat transfer performance has occurred. This reduces boiler efficiency and increases bagasse consumption. The FURNACE code has been able to predict whether or not modifications to convection bank design will change heat transfer performance but has not been able to accurately predict the magnitude of these changes. This paper describes modifications that have been made to the FURNACE code to improve the prediction of heat transfer performance. Comparisons with boiler operating data are used to assess the upgraded FURNACE code. In this work the ability of the FURNACE code to predict the changes in convection bank heat transfer performance caused by baffle modifications has been improved significantly. The upgraded FURNACE code successfully predicted most of the increase in convection bank exit gas temperature caused by convection bank baffle modifications in two boilers. For one boiler the model predicted a convection bank gas exit temperature rise of 33C versus an actual temperature rise of 36C. The predicted convection bank gas exit temperature rise for the other boiler was 76C and the actual temperature rise was 92C. Further testing of the model will be performed using data from other boilers with a wider range of convection bank baffle configurations. The model will be applied in the future to achieve the combined aims of improved heat transfer and reduced wear in convection banks and other boiler components.

Canegrub Damage; Remote Sensing; Satellite Imagery; Mapping; Object-based Image Analysis

CANE TRANSPORTATION

EARTHWORM SPECIES

ADMINISTRATION, COMPUTER SYSTEMS

PAN STATION

ASSCT CONFERENCE PROCEEDINGS, PAN STATION

The design of Roberts evaporators in the Australian sugar industry is currently based on parameters evolved from experience with a limited amount of experimentation into some of the critical design criteria. Numerous configurations of juice inlets and outlets, calandrias and downcomers exist in the industry. Experimental and computational fluid dynamics (CFD) modelling studies were undertaken to identify design modifications to Roberts evaporator vessels that could lead to an increase in throughput capacity. Residence time and heat transfer trials were conducted on an existing evaporator set to provide data for fluid dynamics modelling. A CFD model of the first vessel of the set was developed. In addition, two alternative evaporator configurations were explored with CFD. The following conclusions are drawn from the experimental and modelling work. The optimal flow pattern of juice inside an evaporator vessel is plug flow, with no internal recirculation, stagnant regions or bypassing. The calculated benefits from plug flow on the throughput capacity of an effect range from 4% for the No. 1 effect to above 30% for the final effect. The evaporator vessels, which typically have three peripheral juice inlets and a single central juice outlet, showed significant mixing and recirculation of the juice, as well as short-circuiting of juice from the feed inlet to the outlet. This was seen in both the experimental data and the CFD model predictions. CFD modelling of alternative evaporator configurations has indicated that the preferred configuration is a vessel with fully distributed feed and a single central outlet.

Top-Shoot Borer; Scirpophaga excerptalis; Estimating Losses

CANE TRANSPORTATION

WATER MANAGEMENT

CLARIFIER STATION, INSTRUMENTATION AND CONTROL

K-factor methods are used for estimating pressure losses in fittings; but for massecuite handling systems operating at low Reynolds number, information from raw sugar factories suggested that the pressure loss due to fittings may be overestimated. This re

Stage I of a major research, development and demonstration program has been completed by the Sugar Research Institute and the University of Queensland on behalf of the Queensland Biomass Integrated Gasification (QBIG) group. The aim of the QBIG group is to develop advanced (gasification) cycles for increased power export from the sugar industry. This first stage is aimed at providing the necessary technical and financial input required to progress the research program to the full prototype development and demonstration stage. The paper describes progress in five critical path components of the project, namely: • The development of an experimental facility to establish the kinetics associated with bagasse char gasification. • The design construction and testing of a unique continuously feeding device for delivering bagasse and blends including other biomass fuels into a pressurised gasifier. • A site-specific technical and economic evaluation of the implementation of bagasse gasification power generation technology located at an Australian raw sugar factory. • The development of a high pressure and temperature experimental facility to determine bagasse ash characteristics during gasification. • The design, construction and testing of a prototype dry cane separation plant as a means of recovering sufficient cane trash as fuel to provide the size and associated economies of scale for the economic viability of gasification technology. An overview of the work to date in these areas as well as future plans, is presented.

Pachymetra Root Rot; Surveys; Tully; Spores

MAINTENANCE