International Journal of Emerging Technology and Advanced Engineering Website: www.ijetae.com (ISSN 2250-2459, ISO 9001:2008 Certified Journal, Volume 4, Issue 3, March 2014) 730 Exergy Analysis of an Industrial Sulphuric Acid Plant William Ruiz Civetta 1 , Ricardo Vasquez Padilla 2 , Antonio Bula Silvera 3 , Arturo Gonzalez Quiroga 4 1,2,3,4 Department of Mechanical Engineering, Universidad del Norte, Km 5 Via Pto Colombia, Barranquilla, Colombia Abstract— This paper presents an exergy analysis of an industrial 45 Ton/day sulphuric acid plant. Magnitude and location of irreversibilities for the main equipment of the process have been quantified. Gross irreversibilities represent 78.4% and exergy gains represent 11.4%; i.e., net irreversibilities of the plant are 67.1%. Irreversibilities due to chemical reactions and heat transfer are 26.4% and 52.1%, respectively. For chemical reactions the greatest irreversibilities are located at the furnace, while for heat transfer the greatest irreversibilities are located in the waste heat boiler and the heat exchanging network of the catalytic converter. The obtained exergy efficiencies are consistent with those reported in the literature for sulphuric acid production plants. Further improvements in exergy efficiencies could be reached by resetting operating conditions and by reconfiguring the heat exchanging network of the catalytic converter. Keywords—Chemical Reactions, Exergy Analysis, Exergy Efficiency, Grassmann Diagram, Heat Transfer, Industrial Plant, Irreversibilities, Sulphuric Acid I. INTRODUCTION Sulphuric acid (H 2 SO 4 ) is considered the chemical with the highest total annual production around the world. Principal uses of H 2 SO 4 include ore processing, fertilizer manufacturing, oil refining, wastewater processing, and chemical synthesis (Chemsystems, 2009). One approach for increasing the efficiency of H 2 SO 4 production plants is related with decrease of energy expenses. This increase in efficiency could be attained through more efficient utilization of the thermal energy released during the production process. Exergy, as a measure of the quality of energy, can be considered to quantify and locate the relative magnitudes and the nature of energy degradation, and to expose the potential for improvements in the efficiency of the plant. Some previous studies have been focused on exergy analysis of the H 2 SO 4 manufacturing processes. Kotas (1985) carried out an exergy analysis on a conceptual H 2 SO 4 production plant where thermal energy is used in the process itself for sulphur melting, and steam production. In that study, exergy flows and irreversibilities were represented by means of the Grassmann Diagram. The exergy efficiency of a H 2 SO 4 production plant from liquid sulphur was evaluated by Rasheva & Atanasova (2002) with temperature and pressure data taken from the literature. The plant analysed by Rasheva & Atanasova (2002) presented two stages of conversion with intermediate adsorption; H 2 SO 4 throughput is not reported in this study. Magaeva et al., (2000) carried out and exergy analysis of a H 2 SO 4 production plant with SO 2 rich gases from metallurgical processes as raw material. So far, however, research has tended to focus either on literature data or real plant data without reporting pressure, temperature and exergy of each stream. This study presents an exergy analysis of an industrial 45 Ton/day H 2 SO 4 production plant. Real pressure and temperature for each stream are reported along with the calculated exergy. The magnitude and location of irreversibilities for the main equipment of the process are quantified. Results are depicted in a Grassmann diagram which allows identifying exergy flows along with exergy efficiencies. Results are compared with previous studies and the main differences that were found are explained. Finally, technical recommendations to reduce exergy losses are given. II. METHODOLOGY Process description The chemical reactions of the process consist of burning sulphur (S) in air to form sulphur dioxide (SO 2 ), converting SO 2 to sulphur trioxide (SO 3 ) using molecular oxygen (O 2 ) from air, and absorbing SO 3 in a diluted solution of sulphuric acid (H 2 SO 4 ) to form a concentrated solution of sulphuric acid (around 97.8%). Equations 1 to 3 represent the above mentioned chemical reactions (Kiss et al., 2010; IDAE 1982). () () ⇔ () () () ⇔ ()