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Groundnut oil mill plant

Groundnut oil mill plant

Decortication, cooking and double pressing for groundnut, the highest-oil seed in common Indian use and the least forgiving of an uneven feed.

46%Oil content of the seed

2 line optionsHow the presses are set up

7Machines for this crop

See the full process line

Setting up in Gujarat? Groundnut and cottonseed oil mills for Gujarat

Why this crop is different

Crushing Groundnut

Groundnut carries one of the highest oil contents of the common Indian oilseeds, which makes it a straightforward double press but a demanding one: a high-oil seed floods a press that is fed unevenly, so feeding and cooking matter more here than on a low-oil seed. The cake is valuable as feed, which is why mills watch protein as closely as they watch oil.

Groundnut is decorticated before it reaches the press — the shell is abrasive and carries no oil, so pressing it wastes wear and dilutes the cake.
Decorticated groundnut and whole pods are different machines. Tell us which you are starting from.

Plan a line for this crop

Process flow

How a groundnut oil line works

Follow the seed from left to right. The numbers on the drawing match the steps below it, and every machine is explained in plain words. We build this line in 2 ways. Open each to compare.

Single-time crushing

Shells are cracked and removed first, then three presses work side by side from one shared feed. The oil is filtered twice to give pure crude oil.

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The line, step by step

Clean the seed

Seed arrives from the field with dust, straw and stones in it. All of that is taken out first, because it wears the press and spoils the oil.

1
Seed cleaner
Shakes the seed over screens to take out dust, straw and anything larger or smaller than the seed.
Cyclone and blower: Sucks away the light dust and drops it in one place, keeping the air in the mill clean.
2
Destoner
Removes stones, which are the same size as seed but heavier. One stone can damage the press.
3
Groundnut decorticator
Cracks the groundnut shells open so the nuts inside can be freed.
4
Shell vibro separator
Shakes the broken shells away from the nuts. Shell holds no oil, so it should not go to the press.
Shell goes to husk processing
5
Seed storage silo
Holds clean seed ready for pressing. A rotary valve at the bottom lets it out at a steady rate.

Moved between machines by: Bucket elevator, Screw conveyor

Warm the seed

Warm, evenly moist seed releases its oil far more easily than cold seed.

6
Boiler
Makes the steam that heats the cooker.
7
Seed cooker
Warms and stirs the seed with steam. Warm seed gives up its oil far more easily, like warm butter compared with cold.

Squeeze out the oil

This is where seed becomes two products: oil, and a dry cake known as meal.

8
Final press ×3
Oil expeller · Double chamber · Optiflow 30
The heart of the mill. A turning screw squeezes the seed harder and harder until the oil runs out through narrow gaps, leaving a dry cake.

Moved between machines by: Bucket elevator

Cool the cake

Optional

Cake leaves the press hot. A cooler brings it down before bagging so it stores well. Not every line needs this.

9
Meal cooler
A slowly turning drum with air drawn through it cools the warm meal, so it stores safely in bags.

Weigh and bag the meal

The meal is weighed into bags. It is valuable in its own right, usually as animal feed.

10
Batch hopper and weighing machine ×3
Holds the meal and weighs out each batch into a bag.
11
Bagged meal
The pressed seed, sold as animal feed or sent on for further processing.

Moved between machines by: Screw conveyor, Bucket elevator

Separate the oil from the solids

Oil leaves the press cloudy with bits of seed, called foots. These are sifted out and sent back to the press, and the oil moves on.

12
Vibro sifter
The oil from the press is cloudy with bits of seed, called foots. This vibrating screen lets the oil through and holds the bits back.
13
Paver chain conveyor
Carries the wet bits caught by the sifter back up, so they go through the press again and their oil is not wasted.
Solids return to the press
14
Settling oil tank
The oil rests here while the finer particles sink to the bottom, and a slow stirrer keeps the tank even.

Moved between machines by: Screw conveyor, Pump

Filter the oil

The oil is pushed through filters until it runs clear, then stored.

15
Pre filter press
The first filter. Takes out most of the fine solids that are left in the oil.
16
Second filter press
Filters the oil a second time, for a clearer finished crude oil.
17
Filtered oil tank
Stores the clear oil after filtering.

Moved between machines by: Pump

The oil ends here: Pure crude oil, ready for storage and distribution

Double-time crushing

Shells are removed first, then the seed goes through two presses in a row. The pre-press takes most of the oil, and the final press squeezes the same cake again. The oil is filtered once before it goes to storage and the refinery.

Swipe sideways to see the whole drawing.Open the full drawing