process control in sugar industry
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GROUP MEMBERSJunaid korai 14CH03Imtiaz Bhurt 14CH17Faisal Bhangwar 14CH30Abdul Haseeb 14CH34Muhammad Saleh 14CH41Abdullah Gopang 14CH51
Instrumentation in sugar industryInstrumentation is the art and science of
measurement and control of process variables within a production or manufacturing area. The process variables used in industries are Level, Pressure, Temperature, Humidity, Flow, pH, Force, Speed etc.
When a device is designed to perform without the need of human inputs for correction it is called automatic control
Goal InstrumentationInstrumentation and control engineers works
with the goal of improving.
Productivity,Optimization,Stability,Reliability,Safety,Continuity.
SensorsSensor measure the physical quantity and
converts into signal which can be observed by observer or by an instrument.
E.g, thermocouple measure the temperature and converts it into the voltage which can be observed by voltmeter.
Process steps in sugar industry Cutting or slicing
Juice Extraction
Clarification (juice purification)
Evaporation
Crystallization
Centrifugaling
Drying and Screening
CUTTING or SLICINGThe cane is cut into small pieces.
Here, We control the flow rate of cane towards the cutter & the size of pieces.
& the flow rate is depend upon capacity of the cutter.
Juice extractionHere the juice is extracted from sugar cane
Juice extraction is the process of squeezing the juice from the cane under a set mills using high pressure between heavy iron rollers. Those mills can have from 3 up to 6 rolls.
Before , entering in the rollers there is electric magnetic drum which removes the metallic parts present in raw material.
Juice extraction During grinding, hot water is sprayed on to
the sugarcane to dissolve any remaining hard sugar. The smaller pieces of cane are then spread out on a conveyer belt.
Juice clarificationIn juice clarification tank , a PH detector is
fitted which measure the PH of the juice .
Sugar cane juice has a pH of about 4.0 to 4.5 which is quite acidic. Calcium hydroxide, also known as Milk of lime or limewater, is added to the cane juice to adjust its pH to 7.
Here the Controlling Variable is PH maintaing.
PH measuring methodsMeasuring PH by using indicator.
Hydrogen electrode method.
Semi-conductor sensor method.
PH imaging.
Evaporator• Generally the evaporators are used to
remove the water percentage from the Juice,
• three vacuum-boiling cells or bodies are arranged in series so that each succeeding body has a higher vacuum (and therefore boils at a lower temperature).
• The syrup leaves the last body continuously with about 65 percent solids and 35 percent water.
Controlling variable in EvaporatorThe controlling variable in Evaporator are
Feed flow rateConcentration (composition)TemperatureSteam flow rate
Crystallization & CentrifugingThis syrup is further concentrated under
vacuum in a vacuum boiling pan until it becomes supersaturated.
This method boils the sugar liquors in three stages, called A-, B- and C-.
The mother liquor from the first crystallization step (A-product) is again crystallized in vacuum pans and then passed through continuous sugar centrifuges
Crystallization & CentrifugingThe mother-liquor is again crystallized in
vacuum pans for sufficient to exhaust molasses (called massecuite).
Then the massecuite is re-heated in order to reduce its viscosity and then purged in the C-produced centrifugals.
The remaining mixture is a thick mass of large crystals, which is sent to a centrifuge to spin and dry the crystals. The dried product is raw sugar
DryerDryer removes the Moisture content from
sugar Granulators.
Controlling variables areFeed flow rate,Hot air flow rate,Moisture
ScreeningHere the sieve separates the regular and
irregular granulators.
The irregular crystals are recycled to the Crystallizer.
Regular crystals go towards to the Packing section
Solid level measuring sensorsVibrating point level sensorsUltrasonic level sensors.Laser sensorsLoad cellRadar sensorsMicrowave level sensorsfloat level sensorsoptical level sensors