Process Analysis for Emission Control withinthe Small Scale Coffee Roasting Industries in Kenya.

Abstract

Roasting of coffee has been practiced for decades since the beginning of the 20th Century. It is a vital stage in the coffee value chain in which the green coffee beans undergo chemical change giving the characteristic coffee flavor. In the beginning, much of the roasting was home based in small batches for personal consumption but later faded with the rise of the commercial coffee roasting companies. Continuous increase in global consumption of coffee products including beverage, fresheners and coffee flavor additives have seen the industry attract small, medium and large scale coffee roasting firms.Green coffee beans contain many chemical compound like proteins, fats, caffeine and organic acids and during roasting out of these compounds some decompose, oxidize while others volatize thus becoming pollutants. Since the emissions associated with coffee roasting process are inevitable, small scale firms in the industry continue to face emission control challenge thus inhibiting their growth and profitability. The purpose of this research was to develop an emission management plan for treatment, control and disposal of air pollutants for a small scale batch –type coffee roasting firm. Case study methodology was utilized to study the emission problem and data collection. Pareto analysis was done to rate the various emissions risk index. Process improvement techniques towards a clean coffee roasting process are presented for cleaning dust, chaffs and smoke which comprises ofvolatile organic compounds (VOCs) and fuel combustion compounds.It has been found that adopting the proposed designs for cyclones and smoke extract hood for a standard 60kg small batch-type coffee roastercouldclean and control the unwanted emissions.