Title: Optimisation of fuel in fire tube saturated steam boiler

Authors: Uzair Ibrahim; Sarah Farrukh; Arshad Hussain; Muhammad Bilal Khan Niazi

Addresses: Department of Chemical Engineering, School of Chemical and Material Engineering, National University of Sciences and Technology, Islamabad-44000, Pakistan ' Department of Chemical Engineering, School of Chemical and Material Engineering, National University of Sciences and Technology, Islamabad-44000, Pakistan ' Department of Chemical Engineering, School of Chemical and Material Engineering, National University of Sciences and Technology, Islamabad-44000, Pakistan ' Department of Chemical Engineering, School of Chemical and Material Engineering, National University of Sciences and Technology, Islamabad-44000, Pakistan

Abstract: Considerable improvements have been made to minimise the fuel consumption in industrial boilers since a sizable portion of the operational cost can be reduced with fuel optimisation. In this study a combination of air preheater and condensing economiser is proposed to optimise the fuel usage in a fire tube heat boiler. The process utilises 10% excess air that is preheated to 96°C in an air preheater using the heat of stack flue gases. This improves the boilers efficiency by 3%. Moreover, makeup water is also heated to 84°C in the condensing economiser using the heat of stack flue gases coming from the air preheater. This proposed assembly extracts most of the energy from stack flue gases before it start to condense. A simulation using ASPEN HYSYS® shows that using preheated make up water and preheated combustion air, fuel demand in the boiler is reduced by 10%, thus making the process more economical.

Keywords: fire tube boiler; fuel optimisation; air preheater; condensing economiser; efficiency; sensitivity analysis; ASPEN HYSYS; flue gas; saturated steam; natural gas; combustion air; combustion efficiency.

DOI: 10.1504/IJEDPO.2019.101722

International Journal of Experimental Design and Process Optimisation, 2019 Vol.6 No.2, pp.189 - 200

Received: 27 Oct 2018
Accepted: 04 Jun 2019
Published online: 22 Aug 2019 *

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