# Exergy Analysis of Sulfuric Acid Production: A Systematic Framework Using UniSim Design

## TL;DR

This paper introduces a framework for analyzing energy efficiency in sulfuric acid production using simulation software.

## Contribution

A systematic exergy analysis framework implemented directly in UniSim Design for industrial chemical processes.

## Key findings

- The sulfur-burning furnace and heat exchangers cause over 70% of exergy destruction.
- Increasing steam pressure reduces lost work by 1.33% and boosts potential power generation by 16%.
- Exergy efficiency rises from 21.02% to 48.25% when product stream exergy is considered.

## Abstract

This study proposes a systematic framework for exergy
analysis
of chemical processes implemented directly in UniSim Design and demonstrates
its application to sulfuric acid production via the double contact
process. Thermal, mechanical, and chemical exergies are evaluated
within the simulator, enabling an integrated assessment of unit- and
plant-level irreversibilities. Results indicate that the sulfur-burning
furnace and major heat exchangers account for more than 70% of total
exergy destruction. Increasing steam pressure from 42 to 60 bar reduces
lost work by 2381 kW (1.33%) and increases potential power generation
by 16%, whereas optimization of selected heat-exchanger outlet temperatures
yields only marginal improvements. Process rearrangement of the furnace
and heat recovery section confirms that the associated irreversibilities
are unavoidable and endogenous. The overall plant exergy efficiency
is 21.02%, increasing to 48.25% when product stream exergy is included.
Grassmann diagrams are used to visualize exergy flows and losses.
The results demonstrate UniSim Design as a robust and transparent
platform for applied exergy analysis of industrial processes.