Electric preheating of combustion air

Design of a cost-effective and compact electric combustion air preheater for the LSV® burner

Master thesis (2021)

Authors

B.M. van Veen Mechanical Engineering

Contributors

D.J.E.M. Roekaerts Fluid Mechanics - Mechanical, Maritime and Materials Engineering (mentor)
Iek Risseeuw Technip Benelux B.V. (mentor)
Faculty
Mechanical Engineering, Mechanical Engineering
Copyright: © 2021 Bas van Veen
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Published Date

09-07-2021

Language

English

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Faculty

Mechanical Engineering

Abstract

This thesis report discusses the design of a cost-effective and compact electric combustion air preheating for the LSV® burner. The industry has a complex problem to solve and an important role to play during the energy transition, that is needed because of global warming. Many industrial processes use heat generated by the combustion of fossil fuels. An alternative sustainable solution needs to be chosen in the future. Fossil fuels can be replaced by biofuels, hydrogen, electric power or a hybrid solution.

For this study a solution using electric power is investigated, which could also be used in a hybrid solution. Electric combustion air preheating can be used to shift the energy input from fuel energy to electrical energy. This is new since normally combustion air preheating is accomplished in the convective part of the fired heater. A system to heat up the combustion air to a temperature of 300°C is designed using correlations for tube banks and CFD modelling. An experiment is also conducted to investigate the impact of the combustion air preheater on the burner and fired heater performance. It is important that the burner and fired heater performance remain almost unchanged since the whole fired heater is designed around specific performance parameters.

The design includes a staggered and finned tube bank that can reduce CO2 emissions with 3.2 % by using green electricity when operating 3000 hours per year. This method for combustion air preheating will also result in an operating cost reduction and a payback time of less than five years. A drawback of this system is that the NOx emissions will increase by a factor of 2, which is bad for the environment since it is responsible for the formation of smog and the general acidification of soil and water. This could be avoided by improving the burner design or applying other combustion control mechanisms.

The outcome shows that electric combustion air preheater is suitable technology for CO2 emissions reduction in the short term for fired heaters. With the increasing CO2 emissions cost and increasing volatility of the electricity market, this is an attractive grid balancing equipment.