Effects of H₂O in the Feed of Sulfur Recovery Unit on Sulfur Production and Aromatics Emission from Claus Furnace

Abstract

An increase in the exploitation of sour reservoirs with a high content of acid gas (mainly H 2 S and CO 2 ) and the enforcement of stringent emission standards have triggered demand for high sulfur recovery efficiency in sulfur recovery units (SRUs). The high amount of H 2 O that is present in feed gases to the SRU can act as a diluent in the thermal section of the SRU and can also pose operational difficulties and have substantial chemical effect on the equilibrium-limited reactions of sulfur production and the destruction of impurities. This paper explores the role of H 2 O (0−12% in the furnace feed) in sulfur recovery and in the fate of undesirable aromatics, COS, and CS 2 in the thermal section using a detailed reaction mechanism and industrial SRU operating parameters. An increasing H 2 O concentration in the feed decreased the sulfur recovery efficiency in the thermal section significantly, as the equilibrium conversion of H 2 S to sulfur was affected. The higher H 2 O concentrations increased the concentrations of H 2 S, H 2 , and SO 2 at the furnace exit because of the production of OH radicals from enhanced chemical decomposition of H 2 O by active radicals such as SH, O, and H. It also increased the quantity of unwanted aromatics exiting the Claus furnace, but COS and CS 2 production declined because of the fall in the decomposition of CO 2 and feed hydrocarbons as the furnace temperature decreased. This study provides guidelines to increase sulfur production in the thermal section and reduce the number of catalytic stages to decrease SRU operational cost.

Investigating efficiency improvement in sulfur recovery unit using process simulation and numerical modeling

“…Not to mention, enriched acid gas streams should be free of water as in the presence of water, hydrogen sulfide reacts with iron in the construction material and promotes cracking the infrastructure [18]. Ibrahim et al [23] showed that the presence of water not only worsens the thermal efficiency in the reaction furnace, but also promotes the production of unwanted aromatic hydrocarbons.…”

Exergy Study of Sour Water Stripper Unit of Delayed Coker Unit in a Refinery plant: A Real Start-Up Plant

“…The overall energy balance equation is as follows: (11) The enthalpy difference is calculated based on the following equation (12) The kinetic energy is calculated based on the following equation: (13) The potential energy is calculated based on the following equation:…”

“…Hydrogen Sulphide is used as feed to sulphur recovery plants (SRU) to produce elemental Sulphur [9,10]. The main purpose of SRU plants is to prevent H2S emissions against environmental regulations in the world [11,12,13]. The modified Claus process is the most used one to produce Sulphur [14].…”

Effects of Oxygen Enrichment on Natural Gas Consumption and Emissions of Toxic Gases (CO, Aromatics, and SO2) in the Claus Process

“…The detailed mechanism used for the Claus furnace simulations has been validated using much experimental data from the laboratory-scale setups and the industrial Claus process plant in the UAE . Its submechanisms on H 2 S, CO 2 , COS, CS 2 , and hydrocarbon were validated successfully in refs and , while the H 2 O submechanism was validated in refs and . However, before using the adopted mechanism to substantiate the role of oxygen concentrations on the emissions of toxic byproducts such as CO and SO 2 in the Claus furnace, it was necessary to validate the CO submechanism using the recent experimental data on CO oxidation in the presence of CO 2 , N 2 , and SO 2 , in order to enhance the reliability of the simulation results.…”