The objective of the study, published in the journal Food and Bioproducts Processing, was to determine a more efficient industrial cocoa production method in order to boost revenue for the sector in Malaysia, which has seen a decline in cocoa bean tonnage output rates in recent years.
The authors explain that the computer-aided process simulation (CAPS) technique is an effective tool for process analysis and can help plants managers in their adoption of best practice processing methods for cocoa powder, butter, cakes and liquor products.
The CAPS modelling approach involves “the use of computers to perform steady-state heat and mass balancing, as well as sizing and costing calculations for a process,” they said.
It also enables the identification of missing parameters and predicts the behaviour of an integrated process under varying operating conditions. The CAPS tools that are equipped with economic analysis function can be used to pin-point the economic “hot-spot” of a process, continued the researchers.
They claim that cocoa processing, involving cleaning, roasting, winnowing and breaking, alkalisation, drying, grinding, crushing and pulverising steps, is normally operated in semi-continuous mode, and this adds to the difficulty in optimising the various unit operations involved.
The authors said that an industrial cocoa manufacturing process was modelled based on data collected from a production plant as well as from the literature. CAPS was used to identify the process bottlenecks, with several strategies then developed to remove these.
Economic evaluation was also performed on each debottlenecking scheme to identify the most viable method, they added.
Alkalisation was identified as the main process bottleneck, with tray drying also seen to be a process step inhibiting higher throughput gains.
“The alkalisation vessel limits the throughput of the current production scheme. In order to have higher production throughput, this bottleneck needs to be eliminated. This can be done by adding an additional alkalisation vessel operated in stagger mode with the existing vessel.
In practise, the newly added vessel will be operated in parallel with the exiting vessel, but at slightly different time. The simulation model will determine the appropriate start time of this newly staggered equipment… With the availability of the new vessel, the alkalisation process of a consecutive batch can now start before the end of an earlier batch,” they observed.
The researchers concluded that the schemes they developed, based on the stimulation model, showed that by staggering the bottleneck equipment, cocoa product manufacturers could double their current production rate to an output of 5,276 batches on an annual basis.
Source: Food and Bioproducts Processing
Published online ahead of print: doi:10.1016/j.fbp.2010.09.013
Title: Process Simulation And Debottlenecking For An Industrial Cocoa Manufacturing Process
Authors: D. C.Y. Foo, O. Alshekhli, C. Lik HII, C. Lim Law