Dynamic Boiler Performance: Modelling, simulating and optimizing boilers for dynamic operation

Research output: Book/ReportPh.D. thesisResearch

Abstract

Traditionally, boilers have been designed mainly focussing on the static operation of the plant. The dynamic capability has been given lower priority and the analysis has typically been limited to assuring that the plant was not over-stressed due to large temperature gradients.

New possibilities for buying and selling energy has increased the focus on the dynamic operation capability, efciency, emissions etc. For optimizing the design of boilers for dynamic operation a quantication of the dynamic capability is needed.

A framework for optimizing design of boilers for dynamic operation has been developed. Analyzing boilers for dynamic operation gives rise to a number of opposing aims: shrinking and swelling, steam quality, stress levels, control system/philosophy, pressurization etc. Common for these opposing aims is that an optimum can be found for selected operation conditions.

The framework has been developed as open, i.e. more dimensions and their corresponding quanti- cation can be added. In the present study the dynamic capability has been quantied and the feasible set for the optimization has been limited by means of a number of constraints. The constraints are: (i) simple constraints related to the geometry and min/max gradients and/or load changes, and (ii) constraints derived from dynamic models related to shrinking and swelling and steam space load. Two boiler types were selected and an experimental verication of the dynamic model for one of these has been carried out.

As a result of the analysis for selected operating conditions the optimum design for dynamic operation of the plants has been assessed.

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Traditionally, boilers have been designed mainly focussing on the static operation of the plant. The dynamic capability has been given lower priority and the analysis has typically been limited to assuring that the plant was not over-stressed due to large temperature gradients.

New possibilities for buying and selling energy has increased the focus on the dynamic operation capability, efciency, emissions etc. For optimizing the design of boilers for dynamic operation a quantication of the dynamic capability is needed.

A framework for optimizing design of boilers for dynamic operation has been developed. Analyzing boilers for dynamic operation gives rise to a number of opposing aims: shrinking and swelling, steam quality, stress levels, control system/philosophy, pressurization etc. Common for these opposing aims is that an optimum can be found for selected operation conditions.

The framework has been developed as open, i.e. more dimensions and their corresponding quanti- cation can be added. In the present study the dynamic capability has been quantied and the feasible set for the optimization has been limited by means of a number of constraints. The constraints are: (i) simple constraints related to the geometry and min/max gradients and/or load changes, and (ii) constraints derived from dynamic models related to shrinking and swelling and steam space load. Two boiler types were selected and an experimental verication of the dynamic model for one of these has been carried out.

As a result of the analysis for selected operating conditions the optimum design for dynamic operation of the plants has been assessed.

Original languageEnglish
Place of PublicationAalborg
PublisherInstitut for Energiteknik, Aalborg Universitet
Number of pages184
ISBN (Print)87-89179-52-8
StatePublished - 2004
Publication categoryResearch

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