AbstractsEngineering

Process analysis and energy efficiency improvement on Portland limestone cement grinding circuit

by Sixto Humberto Aguero




Institution: University of British Columbia
Department: Mining Engineering
Degree: Master of Applied Science - MASc
Year: 2015
Record ID: 2058345
Full text PDF: http://hdl.handle.net/2429/52867


Abstract

Worldwide cement production is a high energy consuming industry; 90% is thermal and 10% is electrical energy. This is the third most anthropogenic related carbon dioxide emitting industry in the world. With a rising price of energy and a growing emphasis on environmental issues the cement industry is facing significant challenges to both remain a competitive and sustainable. Composite cement manufacturing is one alternative that is used reduce energy use and greenhouse gas emissions. The dry grinding process used for finished product represents 40-50% of electrical energy consumption. It is a very inefficient process generally ranging around 1% efficient. This research evaluated the process of a typical Portland cement grinding circuit in order to identify inefficiencies in the process and how the operating parameters may be changed in order to improve the system’s performance. Tests were conducted using samples from a B.C. cement producer and results analyzed in order to characterize and build a high accuracy model that can be used as a bench marking tool. Representative sampling and mass balance were performed on the circuit using real steady state operative conditions data provided by process plant managers. Major research findings are: • Air separator efficiency is rated 46.06% efficiency at fractions below 35 microns. • High dust load feed and agglomeration are the main reasons for this low separator efficiency. • Agglomeration effect is related to overgrinding, high energy impacts and the use of limestone. • Whiten model is an adequate tool to fit and correct experimental data on cement air separators and to provide quantification of operating factors to evaluate the separation process. • Low grinding kinetics at ball mill compartment 01, suggests improper size grinding media selection and high wear rate for the case studied (for media and liners).