Optimized Rice Processing Equipment and Solutions

Rice is possibly the grain that has been cultivated for a longer time and more extensively, occupying approximately 9% of the total arable land and is the second cereal in importance for human nutrition, after wheat. It is currently the food base of two-thirds of the world’s population.

Grinding in rice differs completely from that of wheat. Wheat is milled to obtain flour, while rice grinding includes husking, bran removal and finally separation of broken and damaged grains.

Rice from the field is the whole, known worldwide as “paddy” or paddy rice; contains fibrous and inedible outer shell called husk (glumes and glumes). When the peel is removed, but the pericarp (the bran) and the germ are preserved, brown rice is obtained, which after polishing is transformed into white rice. Rice is produced only for human consumption as a feed.

The most important quality criteria for rice are the grinding efficiency, the appearance of the raw grain, the cooking behavior and the texture and aroma of the cooked grain. The milling yield is a measure of the proportion of unbroken whole grains and reflects the variety, conditions of cultivation, harvesting and subsequent management. In the appearance of the raw grain the biometry (dimensions and shape of the grain), the color and characteristics of the pearl (dark areas of the grain, without crystallinity) participate.

The rice is transported to the rice mill plant, then it is emptied into hoppers, which using elevators and conveying augers is taken to the silo receiving damp rice, and from there they are distributed to the different towers of drying, according to the size of the modern rice mill plant. In these towers, the rice is subjected to a drying process by air or heat to reduce the moisture of the grain, to the optimal parameters for its storage (12.5% – 13.5%).

During storage, the rice is attacked by insects, rodents and fungi, which will affect the product under different weather conditions. The reduction can influence the quantity; hence, corrective measures are taken to prevent these agents from being combated quickly and efficiently.

The rice, after being dried and stored, passes to the rice milling machine where it will be processed for the consumption of the population.

Mill plant layout and Design

As a first step, the dry paddy rice is passed to a cleaning machine, which will give it a final purification process. Then they are moved to a rubber roller shell where the grain is separated from the shell by 95%, expelling is covered, and the product is peeled with part of it. These peeled grains are sent to the densimetric table where the separation of rice is done. The peeled grain follows the process towards the rice polishers, where the removal of the surface layer or bran is done; this method is called grain polishing. Rice bran or “powder” is used as animal feed; the polished rice is transported towards the classifiers where the whole grain is separated, and the broken grain is classified.

After the rice is processed, it is transferred to the packer to be packed either in plastic bags or bags.