Analysis of the contribution made by the clinker cement manufacturing process to greenhouse gas emissions in Uganda.

Abstract

The cement industry is a major contributor to global warming and climate change. Cement raw materials produce emissions. The manufacturing operations are also extremely energy intensive, requiring a lot of fuel and ultimately resulting in emissions. The cement industry produces tons of carbon dioxide (CO2), sulphur dioxide (SO2), nitrogen dioxide (NOX), carbon monoxide (CO) total organic carbon (TOC), and nitric Oxide (NO) each year. This research provides an analysis of cement operations and emissions produced in a developing country like Uganda where intense construction activities are being undertaken. This research aimed to determine the major indirect and direct greenhouse gas emissions produced during the clinker production stage of cement production in Uganda. The second aim of the research was to analyze the factors that largely influence the GHG emissions while the third aim of this research was to determine the optimum level for producing less greenhouse gas emissions. Emissions were identified at the clinker production stage by taking daily recordings using data sheets. For the indirect emissions, electricity data in kWh consumed by running factory machinery per day was recorded. This was multiplied by an emission factor for grid electricity in Africa to get the carbon dioxide produced per day. The direct emissions were recorded daily on data sheets for a period of 8 weeks. These readings were recorded from the continuous emission monitoring system (CEMS) machine. CO2 was produced indirectly by the electricity consumed to run the machines with a minimum of 29 kg/t and a maximum of 274 kg/t. The direct GHG emissions produced during the clinker stage include CO and NOX producing 1053mg/Nm3, and 576mg/Nm3 respectively as the highest emissions to answer objective one. Furthermore, with a 95% confidence level, raw materials (kiln feed) used significantly affects TOC, CO2, and CO. Biomass significantly affects TOC, CO2, and CO. Heavy fuel oil significantly affects TOC, CO2, and SO2, Coal significantly affects TOC, CO2, SO2, and CO. The number of kiln operating hours and the level of clinker production significantly affect CO2 an indirect emission. The results also pointed to the production of more clinker leads to less GHG emissions emitted direct and indirect emissions except for total organic carbon which increases greatly as the clinker being produced increases.