Modern sugar-factory equipment for good recoveries, energy efficiency and low costs

摘要

In recent decades, traditional sugar factory equipment has been replaced by new designs aimed at the objectives of increased sucrose recoveries, improved energy efficiency and reduced costs of capital, maintenance and operation. This paper describes some of the most important of this equipment, including novel observations on their features and benefits. Space constraints limit the amount of detail on each item, but references are quoted for more comprehensive information on the equipment:Diffusion extraction to avoid the use of potentially exportable power, increase recoveries and save costs;Direct contact juice heaters for low cost heating without an increase in process's exhaust steam demand;Clarifier mud recycling, to avoid the enthalpy losses, sucrose degradation, condenser power, juice dilution, bagacillo fuel losses and costs of mud filter operations;'Direct clear juice' to further reduce enthalpy and sucrose losses in clarification and save costs;Long tube climbing film evaporators for high capacity, low cost 1st and 2nd effects that minimise sucrose losses and avoid pumping;Horizontally configured vertical tubecontinuous pans that use low grade vapour, avoid steaming out between boilings, avoid stirrers and achieve high exhaustions that minimise reboiling of massecuites;Sieve plate scrubbers for high efficiency cleaning of boiler flue gases at low energy and cost.Where appropriate, results are quoted to demonstrate that the use of these techniques and plant has enabled factories to achieve the desired objectives. Novel equipment covered includes a diffuser processing more than 20,000 t cane per day, a unique evaporator with built-in clear juice heater, and a scrubber achieving emission rates of less than 20 mg/Nm3 at a pressure drop of 600 Pa (60 mm water gauge).