FOOD GRADE BLEACHING EARTH PLANT
Operating Instructions
Dryers
Check the air pressure, temperature and natural gas pressure at the furnaces. Adjust these parameters if any deviation is observed. Normally air pressure should be between 400-450 mm WC and furnace temperature between 415-425 ºC. Check and note them hourly.
Filters
Check the position of the filters, how many under charging and under washing pH to be made 3.0-3.5. When washing process of filters is completed apply hot air to the filters to compact the cake formed in the filters, before emptying them. Get the cake removed from the filters, stack properly in the cake room.
Supply Washing and Settling
Check the settling of slurry in Slurry Washing Pits at regular intervals. Slurry Pits in which slurry have settled up to the lower drain points, to be re-washed if their pH has reached 2.0-2.5. Slurry pits in which pH of the slurry has reached 2.0-2.5 can be lifted to the pressure vessel for charging the filters. Make vacuum of 550-560 mm Hg in the pressure vessel with the help of water ejection system and transfer the slurry of pits in to the vessel via rubber hose. There are two pressure vessels. One vessel will always be charging the filters and other vessel will be under filling from the Slurry Pit.
Reactors
Check the position of reactors. If already in operation, note the starting time of activation from the log sheet (mentioned by out going shift). Check the required quantity of reflux is coming. Check if the required steam pressure is maintained or not. Get it adjusted from the boiler house if any deviation is noted.
Drain the reactor batch in to the empty pit when activation is completed after 2½ hours reaction time. Collect slurry samples in the bottle and sent it to laboratory for testing. Fill the pit with water immediately (and required quantity of flocculent prepared). Charge fresh batch in to the empty reactor according to the instructions of supervisor.
Clay Drying and Pulverizing
Take round of pulverizer room after every two hour. Check the operation of pulveizers. In case of any abnormality, inform the supervisor. Check with physical observation when crashed clay being pulverised is within specified limits of moisture contents. In case of any doubt, send the sample to lab. Check the weight of pulverized clay bags. Pulverizers should be cleaned at the start of every shift.
Wet Grinding
Take round of wet grinding/slurry preparation plant hourly. Any abnormalities noted to be reported to supervisor. Check that specified quantity of clay and water is being added in specified time, in to the rotary grinding mill. Send the samples of slurry from prepared pit to the laboratory for checking its density. Send the samples of slurry from the outlet of rotary mill for checking its density from the lab. Any variation in the density of slurry, from specified limits, to be adjusted accordingly with addition of water or clay.
General
Note the production of dried production lumps bags taken out from the dryers in the morning general shift. Fill the log sheet hourly.
Take all necessary safety precautions during work. Rubber gloves, safety goggles to be used when working with acid.