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

Abstract

The contaminants of acid gas feed to the Claus process plants such as benzene, toluene, ethylbenzene, and xylene (BTEX) increase the operational cost through catalyst deactivation and high fuel gas consumption and impact the sulfur recovery efficiency and the emission of toxic gases (such as CO and SO 2 ). In this study, a detailed and validated reaction mechanism for Claus feed combustion is utilized to simulate the Claus process plant by integrating Chemkin Pro and Aspen HYSYS software. The effect of oxygen enrichment of air on sulfur recovery, BTEX destruction, toxic gas emissions, and fuel gas consumption is studied. Upon increasing the oxygen concentration in air, BTEX concentration decreased substantially due to their enhanced oxidation by SO 2 and O 2 . An increase in oxygen concentration resulted in (a) increased SO 2 emission and decreased CO 2 emission from the incinerator, and (b) decreased fuel gas consumption in the incinerator. Interestingly, CO emission increased with increase in oxygen concentration in air as the furnace temperature increased up to 1350 °C, but it decreased with the further increase in the furnace temperature at higher oxygen concentrations. The reaction path analysis is presented to understand this decrease in CO emissions at high oxygen concentrations. The results demonstrate that a high oxygen concentration in air can be utilized to decrease fuel gas consumption and CO and CO 2 emissions in the Claus process. The oxygen concentration, required to minimize the emission of aromatics, SO 2 , CO, and CO 2 , was dependent on the feed composition, and the developed reaction mechanism can assist in optimizing the oxygen enrichment level required for a given feed in a Claus process plant.

Efficiently Selective Oxidation of H2S to Elemental Sulfur over Covalent Triazine Framework Catalysts

“…4,5 Therefore, selective elimination of H 2 S from industrial processes is extremely necessary and urgent, which has received great efforts in both basic research and practical applications in recent years. 3,6−9 To date, the available techniques for H 2 S elimination include the Claus process, 6−8 FeSO 4 aqueous catalytic oxidation, 12 condensation, 13 adsorption, 9,10 and selective catalytic oxidation. 11,12 The classical technique applied for the removal of high-concentration H 2 S (15−40%) in the industry is the Claus process.…”

“…However, the Claus process exhibits disadvantages such as high cost, needs a very large space, and the tail gas contains a certain amount of H 2 S even for the case of SuperClaus (∼3%) due to thermodynamic limitation. 5,8,13,14 For the removal of lowconcentration H 2 S, selective adsorption and separation were thought to be suitable methods. To make the process green and sustainable, various kinds of solid adsorbents such as nitrogen-doped activated carbons, 15−18 molecular sieves, 19,20 porous organic polymers, 21,22 and metal−organic frameworks 23−25 have been developed.…”

“…Hydrogen sulfide (H 2 S), one of the most toxic gaseous pollutants, mainly originates from scalable utilization of coal, petroleum, and natural gas in the industry. − H 2 S is a kind of acidic, corrosive, and harmful waste gas, and its free emission results in rather serious problems, such as acid rain, destruction of facilities, and threaten to the health of human beings. , Therefore, selective elimination of H 2 S from industrial processes is extremely necessary and urgent, which has received great efforts in both basic research and practical applications in recent years. ,− To date, the available techniques for H 2 S elimination include the Claus process, − FeSO 4 aqueous catalytic oxidation, condensation, adsorption, , and selective catalytic oxidation. , The classical technique applied for the removal of high-concentration H 2 S (15–40%) in the industry is the Claus process. The Claus reaction usually involves two steps: (i) one-third of the initial H 2 S was transformed into SO 2 in a combustion chamber at high temperatures (1000–1200 °C) and (ii) the obtained SO 2 further reacts with H 2 S to produce elemental sulfur under relatively mild conditions in the presence of suitable catalysts.…”

“…The Claus reaction usually involves two steps: (i) one-third of the initial H 2 S was transformed into SO 2 in a combustion chamber at high temperatures (1000–1200 °C) and (ii) the obtained SO 2 further reacts with H 2 S to produce elemental sulfur under relatively mild conditions in the presence of suitable catalysts. However, the Claus process exhibits disadvantages such as high cost, needs a very large space, and the tail gas contains a certain amount of H 2 S even for the case of SuperClaus (∼3%) due to thermodynamic limitation. ,,, For the removal of low-concentration H 2 S, selective adsorption and separation were thought to be suitable methods. To make the process green and sustainable, various kinds of solid adsorbents such as nitrogen-doped activated carbons, − molecular sieves, , porous organic polymers, , and metal–organic frameworks − have been developed.…”

Detailed Reaction Mechanism To Predict Ammonia Destruction in the Thermal Section of Sulfur Recovery Units

“…The furnace is also deployed for the destruction of associated feed impurities including NH 3 (up to 40%), C 1 –C 4 hydrocarbons (<1%), and aromatic hydrocarbons such as benzene, toluene, ethyl-benzene, and xylene (BTEX) present in low concentrations . Out of these impurities, NH 3 is the most resistant one to thermal destruction, and its complete destruction generally ensures that hydrocarbon impurities including BTEX (that require furnace temperatures above 1050 °C) are completely eliminated in the furnace. It is essential to ensure the complete destruction of NH 3 in the Claus furnace because of its capability to pose several technical problems to the SRU operation.…”