ABSTRACT
A motorized rice de-stoning machine was designed, fabricated and evaluated for performance.

The traditional method of rice de-stoning machine characterized with a lot of deficiency in terms local rice containing smaller stones during de-stoning operation.

A lot of energy is expended in solving the problem of operation.

The rice de-stoning consists of the following part: Hopper, Vibrating Sieve, Machine Frame, Pulley, Eccentric Shaft, and Blower.

The factors investigated were feed rate (500g/min) and variety off rice (Bokola, Kodoqiche, AlhajiA’aba).

The result of the evaluation reveals that in Stone Separation Efficiency the third variety has the highest efficiency of (77.3%) and the first variety has the lowest efficiency of 72.6%, while in Rice separation efficiency the third variety also has the highest efficiency of 81.0% and the second variety has the lowest efficiency of 79.0%, the Impurity levels after separation are 7.8%, 7.5% and 6.5% respectively, the Tray losses remains the same.

The rice de-stoning machine was powered by 1hp electric motor and the cost of production was estimated to be 108,700.

CHAPTER ONE
1. INTRODUCTION
1.1 Background of the study
Rice (Oryza sativa) is a cereal belonging to the Gramineae, a large monocotyledonous family of some 600 genera and around 10,000 species (Wibberley, 1989).

It is valued as the most important staple food for over half of the world population (International Year of Rice, 2004) and ranks third after wheat and maize in production on world basis.

More than half of the world’s population depends on rice as the major source of calories (FAO, 2003).

he amount consumed by all these people ranged from100kg to 240kg per annum in the year 2000 alone (FAO,2003).

Two species have emerged as our most popular cultivated rice,Oryza sativaand Oryzaglaberrima; of these two species the more widely produced is Oryza sativa.
Rice is cultivated in almost all part of the globe including Nigeria. By 2015, it has been estimated that over three-fifth of the world population will depend on rice as their staple food (Echiegu, 2009).

Rice is one of the staple foods in Nigeria and it is cherished by almost all the ethnic groups and it is prepare into various delicacies.

For instance, in the northern part of Nigeria, rice can be milled and used for flour and also molded and fried into cakes. Large acres of plantation can be found in these areas, Lafia (northern Nigeria), Beneu state (Middle Belt), Osun state (Western Nigeria), Abakaliki (Eastern Nigeria) and several other places.
In Nigeria, rice consumption has risen tremendously at about 10% per annum due to changing consumer preference (Akande, 2003).

However, (Ebuehi and Oyewole, 2007) discovered that most Nigerians prefer to consume imported rice brands as compared to local rice varieties.

The reason is that most Nigerian rice processors lack adequate technology of rice processing to meet international standard.

It is valued as the most important staple food for over half of the world population (International Year of Rice,2004) and ranks third after wheat and maize in production on world basis.

More than half of the world’s population depends on rice as the major source of calories(FAO, 2003).

The amount consumed by all these people ranged from100kg to 240kg per annum in the year 2000 alone (FAO,2003).

Two species have emerged as our most popular cultivated rice,Oryza sativa and Oryzaglaberrima; of these two species the more widely produced is Oryzasativa.
In Nigeria, rice consumption has risen tremendously at about 10% per annum due to changing consumer preferences (Akande, 2003).

However, Ebuehi and Eyehole (2007) discovered that most Nigerians prefer to consume imported rice brands as compared to local rice varieties.

The reasons that most Nigerian rice processors lack adequate technology of rice processing to meet international standard.

It is one of the most important staple crops in Nigeria, and local production of the commodity has increased several folds in the last 4 decades.

Despite the increasing trend in local production, Nigeria is still a net importer of rice.

n the local markets there is a greater consumer preference for imported rice compared to the locally produced commodity because of some quality issues associated with the local rice.

Presence of stones in locally processed.
Nigerian rice has been identified as one of the major quality problems.

The small Engleberg rice processing mill used by majority of rice processors in Nigeria, which includes a dehusking element and a polisher do not come with de-stoners. De-stoners are found only in a few high-tonnage integrated mills or are sold as separate equipment.
It was in the above context that the DFID-sponsored Promoting Pro-Poor Opportunities in Commodity and Service Markets (PrOpCom, 2012) engaged the services of M & A’s Greenery Ltd to conduct a survey of improved drying and de-stoning techniques and technologies in Nigeria.
1.2 The aim and objectives of the project
The aim of the projects to de-stone rice in other to have clean rice for human consumption.
The specific objectives are to:
i. develop a rice de-stoning machine
ii. evaluate the rice de-stoning machine in terms of impurity level after separation, tray loss, rice separation efficiency and stone separation efficiency.
1.3 Justification of the project
This project leads to the followings, to improve the quality of rice, to increase production, to minimize time and reduce human labor, to reduce losses in de-stoning of rice compare to the local method, to reduce import of rice to the country and to produce job opportunity for the youths in the country.