Processing in addition to harvesting11/28/2006 In the future, Ghana will not only harvest cocoa beans, but also process them into cocoa mass, cocoa butter, and cocoa powder. Bühler is supplying the necessary systems. Ghana is the second-largest cocoa-growing country in the world after its neighbor, Côte d’Ivoire. Up to now, Ghana exported almost its entire crop. But the government under President John Agyekum Kufuor has set itself the goal of broadening the Ghanaian cocoa business by investing in cocoa processing facilities. The target of the government is to process at least 40 percent of the annual cocoa crop of 500.000 metric tons in the country itself.
Exclusive technical partner
The German company MAN Ferrostaal AG was therefore commissioned to update and expand the facilities of the Cocoa Processing Company Ltd. in Tema, in which the state holds a majority stake. The port city of Tema is located in the southwestern part of Ghana on the Gulf of Guinea and – with over 300.000 inhabitants – is the second-largest city in the Greater Accra area. The contract signed with the state, which is worth more than 20 million euros, includes the design and supply of a complete cocoa processing plant including the infrastructure. The capacity of the existing small plant was to be increased to 65.000 metric tons of cocoa beans a year.
MAN chose the Bühler Chocolate & Cocoa business unit as its sole technical partner for handling this large-scale project – thanks to the unit’s outstanding track record. The contract with Bühler was signed in the autumn of 2003 and comprised the design and supply of a complete cocoa processing facility “from the green bean to the cocoa mass.”
The expansion of the cocoa processing facility was designed in two stages. The first phase included the system for processing cocoa beans into cocoa mass. In an initial operation, the dried, green beans are cleaned, weighed, and binned as clean raw material. In a second operation, the beans are debacterized – that is, subjected to a thermal treatment under high pressure and a temperature of 220 °C so that all germs, spores, and bacteria are destroyed. This is followed by bean toasting, during which the moisture is extracted. Finally, the cocoa beans are crushed, and the hulls are separated from the bean fragments called nibs. Only now is it possible to grind the cocoa nibs in two process stages. During this mechanical grinding operation, heat is generated, which makes the cocoa mass melt. The liquid cocoa mass (liquor) with a temperature of about 80 °C is directed to storage tanks, where it is cooled to 45 to 50 °C. From the tanks, the mass is moved to a cooling tunnel, where the heat is extracted and the cocoa mass is formed into blocks weighing 25 kilograms each.
In service since October 2005
The new cocoa processing facility has a capacity of four metric tons per hour. This makes it the most advanced plant of its kind in the whole of Africa. The new cocoa processing line is computer-controlled from a centralized location. It is operated in three shifts, with four persons present per shift. Two mechanics and one electrician take care of maintenance. The staff received in-depth, on-site training from Bühler to prepare them for their demanding tasks. One particular feature of the facility is its emergency generating set which produces 2.500 kilowatts’ power and guarantees an uninterrupted supply of electric power to the entire plant.
The installation and start-up of the new cocoa processing facility in the also new building structure constructed by the customer took about seven months. The plant was inaugurated in a ceremony in October 2005 by President Kufuor. The new facility has been operating without a glitch ever since.
At present, the second construction phase is being executed. It comprises the modernization of the existing plant for further processing of the cocoa mass into cocoa butter and cocoa powder.
The Western African state of Ghana covers 238.537 square kilometers, making it almost six times as big as Switzerland. Formerly known as the “Gold Coast,” Ghana was a British colony since the early 19th century. It gained its independence in 1957. Ghana is one of the major gold production countries and the world’s second-largest cocoa producer. Gold accounts for 32 and cocoa for 20 percent of the country’s exports.