CHEMICAL ENGINEERING TRANSACTIONS
VOL. 67, 2018
A publication of
The Italian Association
of Chemical Engineering
Online at www.aidic.it/cet
Guest Editors: Valerio Cozzani, Bruno Fabiano, Davide Manca
Copyright © 2018, AIDIC Servizi S.r.l.
I SBN 978-88-95608-64-8; I SSN 2283-9216
Mapping of Nonconformities that Impact the Performance of
Cooling Towers: Refinery Case
Jean M. P. Silva*
,a
, Jade S. Ávila
b
, Salvador A. Filho
a
, Reinaldo C. Mirre
a
, Rosana
L. L. Fialho
a
a
Federal University of Bahia, Salvador, Bahia, Brazil
b
Federal University of Campina Grande, Campina Grande, Paraíba, Brazil
jmarcel_7@yahoo.com.br
The current world outlook of supply and demand for basic inputs, such as in the case of water, has created an
alarming situation for all of society, especially the industrial sector. Cooling Towers are the equipment
responsible for the removal of heat from a stream of hot water from an industrial process and at the same time
they are the most water-consuming equipment in the industry. Their good performance is directly linked to the
sustainable consumption of water present in the environment. In this context, audits for the mapping of
nonconformities encountered frequently in tower operation become a useful tool to increase the efficiency of
the equipment. As a step in this mapping and work objective, discussions were carried out on two irregularities
commonly identified in operation, such as: (1) variation of the water feed load; (2) variation of air flow, in
addition to its main causes and impacts on the operation and efficiency of the equipment. Actual data were
obtained for the case study of a tower located in Petroleum Refinery in Brazil. The controlled variable chosen
for the study was the outlet water temperature of the tower. The model used to identify the output temperature
is based on Merkel's theory, using the Tchebeycheff method for numerical integration. Therefore, with the
variations carried out, it is possible to verify the direct influence on the outlet temperature and to identify
possible causes of the irregularities addressed in the study.
1. Introduction
The World Meteorological Organization (2016) states that the main causes of climate change and emissions
are related to anthropogenic emissions of greenhouse gases (GHG). According to the IPCC (2007), CO
2
emissions from burning fossil fuels in industrial processes contributed approximately 78% of the increase in
GHG emissions between 1970 and 2010.
With the modification of the environmental scenario, it is important to highlight the influence of climatic effects
on the reduction of water availability. According to Kim et al. (2014) and Kandu et al. (2017), the temperature
increase in the terrestrial troposphere is a critical factor in predicting and evaluating the future of water
resources. On the other hand, it is noticed that water is the basic input more used in most industrial
processes, standing out in the energy intensifying industries. The withdrawals of water for electric and electric
power generation, as well as for the refining of crude oil, are active and comprise 10% of water abstractions
(IEA, 2016).
Petroleum refineries represent one of the largest consumers of water in their production processes, being
directly related to processed oil (Hwang et al., 2011). According to Peres (2010), the applicability of the water
in the refineries is destined, mainly, for the towers of cooling, corresponding to 60-70% of all the water
consumed in the sector.
Cooling towers are equipment used to control process temperatures, with greater applicability in the industrial
sector. Its operation is based on the simultaneous principle of thermal exchange and mass transfer between
the process hot water flow and the cold ambient air flow. Cooling systems using towers are the most found in
the industry, mainly because they work at high water flows and temperature restrictions for cooling water
users (Ávila et al., 2013). Its application has become a critical factor in several productive processes, raising
DOI: 10.3303/CET1867097
Please cite this article as: Prazeres Silva J.M., Spinola Ávila J., Avila Filho S., Coelho Mirre R., Lopes Lima Fialho R., 2018, Mapping of
nonconformities that impact the performance of cooling towers: refinery case, Chemical Engineering Transactions, 67, 577-582
DOI: 10.3303/CET1867097
577