'MODIFIED EVAPORATOR CONFIGURATION FOR ACHIEVING EFFICIENT STEAM REDUCTION MEASURES TAKEN TO SUSTAIN IT, TO SUIT INTEGRAL SUGAR COMPLEX'

摘要

Heat recovery aspect in case of evaporators is an important development in Sugar Industry. Application of Rellieux principles in case of vapour bleeding from intermittent effects of Multiple effect evaporators is a well known practice in steam economy, nevertheless more pronounced in the scenario of Cogeneration. Considering the present day need, this is an attempt to device an effective evaporator scheme involving Falling film Evaporators in conjunction with Continuous pans for all massecuite boiling & adopting various heat recovery devices to achieve & sustain the reduction in steam consumption. The availability of Exhaust at comparatively higher. Pressure in Cogeneration plants from Extraction cum condensing turbines, enable continuous & steady supply to evaporator station at a desired pressure. We have chosen a Pressure of 1.25 kg/cm~2.g (124 saturation temperature) & the last effect vapours @ 55 deg C @ 0.16 kg/cm~2.abs to have a ΔT of 69 deg. C, results in rearrangement of bleeding pattern. For this application Quintuple effect is more suited than other schemes considering the vapour load conditions. Further we have considered various heat recovery devices such as condensate flash recovery system, Direct contact heaters & replacing medium pressure & low pressure steam applications in Super heated wash water system, Sulphur melting, Seed melting; Molasses conditioning & pan washing etc, brings down the steam consumption at evaporator station considerably. The enthalpy balances for each effect is worked out to estimate the exact, exhaust steam requirement in previous publications & achieve steam economy to the extent of 2% @ evaporator station, which generate substantial revenue both in terms of Bagasse saving & surplus power generation. The concept of floating bodies in case of Evaporators & Continuous pans are Judiciously used to sustain uninterrupted working, which is of paramount importance in case of integral & Cogeneration plants. Here a case of 5000 TCD plant producing plantation white sugar is considered.