A process plant including a Claus reaction furnace, a means of Claus gas cooling, a Claus conversion section, a means for Claus tail gas oxidation and a sulfuric acid section, wherein a sulfuric acid outlet of the sulfuric acid section is in fluid communication with an inlet of said Claus reaction furnace, as well as a related process. The process has the associated benefit of such a process avoiding undesired production of sulfuric acid, as well as reducing the Claus process gas volume.

A process plant including a Claus reaction furnace, a means of Claus gas cooling, a Claus conversion section, a means for Claus tail gas oxidation and a sulfuric acid section, wherein a sulfuric acid outlet of the sulfuric acid section is in fluid communication with an inlet of said Claus reaction furnace, as well as a related process. The process has the associated benefit of such a process avoiding undesired production of sulfuric acid, as well as reducing the Claus process gas volume.

The present invention, in general, relates to portable/transportable apparatuses, methods, and systems for generating and delivering sulfur trioxide on-site or near an item to be treated. The present invention also relates to portable/transportable apparatuses, methods, and systems for removing hydrocarbon contaminants including waxes, paraffins, resins, and ashpaltenes from surfaces and treating the surfaces to reduce hydrocarbon contaminant build-up on the surfaces.

The present invention, in general, relates to portable/transportable apparatuses, methods, and systems for generating and delivering sulfur trioxide on-site or near an item to be treated. The present invention also relates to portable/transportable apparatuses, methods, and systems for removing hydrocarbon contaminants including waxes, paraffins, resins, and ashpaltenes from surfaces and treating the surfaces to reduce hydrocarbon contaminant build-up on the surfaces.

A vanadium-based catalyst comprises an active phase carried on a carrier. The active phase comprises vanadium oxide, potassium sulfate, sodium sulfate, and assistants. The carrier comprises ultra-large-pore silicon dioxide and diatomite, the average pore size of the ultra-large-pore silicon dioxide ranges from 100 nm to 500 nm, and the diatomite is a refined diatomite having a silicon dioxide content of higher than 85% after refinement. The preparation method for the vanadium-based catalyst comprises: 1) mixing potassium vanadium and potassium hydroxide, and allowing a prepared mixed solution and sulfuric acid to carry out a neutralization reaction; and 2) mixing a neutralization reaction product in step 1) with the carrier and sodium sulfate, and carrying out rolling, band extrusion, drying and roasting to prepare the vanadium-based catalyst, assistant compounds being added in step 1) and/or step 2).

A vanadium-based catalyst comprises an active phase carried on a carrier. The active phase comprises vanadium oxide, potassium sulfate, sodium sulfate, and assistants. The carrier comprises ultra-large-pore silicon dioxide and diatomite, the average pore size of the ultra-large-pore silicon dioxide ranges from 100 nm to 500 nm, and the diatomite is a refined diatomite having a silicon dioxide content of higher than 85% after refinement. The preparation method for the vanadium-based catalyst comprises: 1) mixing potassium vanadium and potassium hydroxide, and allowing a prepared mixed solution and sulfuric acid to carry out a neutralization reaction; and 2) mixing a neutralization reaction product in step 1) with the carrier and sodium sulfate, and carrying out rolling, band extrusion, drying and roasting to prepare the vanadium-based catalyst, assistant compounds being added in step 1) and/or step 2).

In a production mode a process for preparing sulfuric acid may involve oxidizing sulfur to sulfur dioxide in a first oxidation stage, and catalytically oxidizing the sulfur dioxide to sulfur trioxide in a second oxidation stage. The sulfur trioxide may be absorbed in at least one absorption stage. In the production mode, process gases from a last of the at least one absorption stage with respect to a flow direction are discharged. In a standby mode of the process, at least one heating stage for heating the process gases is connected. The process gases exiting from the at least one absorption stage are conveyed to the heating stage, and the process gases are circulated via the heating stage, the second oxidation stage, and the absorption stage.

In a production mode a process for preparing sulfuric acid may involve oxidizing sulfur to sulfur dioxide in a first oxidation stage, and catalytically oxidizing the sulfur dioxide to sulfur trioxide in a second oxidation stage. The sulfur trioxide may be absorbed in at least one absorption stage. In the production mode, process gases from a last of the at least one absorption stage with respect to a flow direction are discharged. In a standby mode of the process, at least one heating stage for heating the process gases is connected. The process gases exiting from the at least one absorption stage are conveyed to the heating stage, and the process gases are circulated via the heating stage, the second oxidation stage, and the absorption stage.

The invention is a method and a sulfuric acid plant design for reduction of start-up SO.sub.2, SO.sub.3 and H.sub.2SO.sub.4 emissions in sulfuric acid production, in which SO2 is converted to SO.sub.3 in n successive catalyst beds, where n is an integer >1. The final catalytic beds are used as absorbents for SO.sub.2 to SO3 during the start-up procedure, and one or more of the m beds downstream the first bed are purged, either separately or simultaneously, with hot gas, where m is an integer >1 and m<n, during the previous shut-down. Also, one separate purge with hot gas is used on the final bed.

The invention is a method and a sulfuric acid plant design for reduction of start-up SO.sub.2, SO.sub.3 and H.sub.2SO.sub.4 emissions in sulfuric acid production, in which SO2 is converted to SO.sub.3 in n successive catalyst beds, where n is an integer >1. The final catalytic beds are used as absorbents for SO.sub.2 to SO3 during the start-up procedure, and one or more of the m beds downstream the first bed are purged, either separately or simultaneously, with hot gas, where m is an integer >1 and m<n, during the previous shut-down. Also, one separate purge with hot gas is used on the final bed.