A method and system for cooling sulfuric acid aqueous solutions (H.sub.2SO.sub.4) belonging to the field of chemical processes, which is part of a contact process for production of sulfuric acid with or without energy recovery. The method comprises absorption of SO.sub.3, which produces heated concentrated sulfuric acid and indirectly cooling the hot acid. The method uses a sulfuric acid-inert coolant. A cooling step comprises an intermediate indirect acid-fluid cooling and a second fluid-water or fluid indirect cooling stepthird fluid, wherein when the process is of the type with energy recovery. A third step includes energy recovery, steam generation. A system to perform the method, which works next to the SO.sub.3 absorption tower comprises an acid cooling loop consisting of an intermediate acid-fluid heat exchanger; a second fluid-water heat exchanger, and when the process is of the type with energy recovery, said equipment further includes a steam generation boiler.

A process for preparing sulfuric acid may involve oxidizing sulfur to sulfur dioxide by way of dried air in a first oxidation stage. The sulfur dioxide may then be oxidized to sulfur trioxide in a second oxidation stage. The sulfur trioxide may be absorbed by sulfuric acid in at least one absorption stage. Further, heated sulfuric acid may be drawn off from the absorption stage and used for generating steam. Process gas from an intermediate absorption stage may be recycled to the second oxidation stage and, in some cases, a final absorption stage after the process gas flows through the second oxidation stage.

A process plant for production of sulfuric acid from a process gas comprising SO2, including a process gas inlet, a first SO2 converter having an inlet and an outlet, a first condenser having a gas inlet, a gas outlet and a liquid outlet, a gas mixing device having a first inlet, a second inlet and an outlet, a process gas heater having an inlet and an outlet, a second SO2 converter having an inlet and an outlet, a second condenser having a gas inlet, a gas outlet and a liquid outlet, one or more means for cooling and storage of sulfuric acid and a purified process gas outlet.

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 process for preparing sulfuric acid may involve oxidizing sulfur to sulfur dioxide by way of dried air in a first oxidation stage. The sulfur dioxide may then be oxidized to sulfur trioxide in a second oxidation stage. The sulfur trioxide may be absorbed by sulfuric acid in at least one absorption stage. Further, heated sulfuric acid may be drawn off from the absorption stage and used for generating steam. Process gas from an intermediate absorption stage may be recycled to the second oxidation stage and, in some cases, a final absorption stage after the process gas flows through the second oxidation stage.

In a converter for the catalytic oxidation of SO.sub.2 to SO.sub.3 in a sulfuric acid plant, which comprises a boiler section for the cooling of process gas between catalytic layers (beds), one or more water tube boilers (inter-bed boilers) having horizontal or slightly sloped tubes are used to cool the process gas between the catalytic layers (beds) in the converter. Each water tube boiler is provided with a process gas side bypass to control the temperature to the down-stream catalyst layer.

In a method for cooling of process gas between catalytic layers or beds in a sulfuric acid plant, in which sulfuric acid is produced from feed gases containing sulfurous components like SO.sub.2, H.sub.2S, CS.sub.2 and COS or liquid feeds like molten sulfur or spent sulfuric acid, one or more boilers, especially water tube boilers, are used instead of conventional steam superheaters to cool the process gas between the catalytic beds in the SO.sub.2 converter of the plant. Thereby a less complicated and more cost efficient heat exchanger layout is obtained.

Sulfur trioxide is produced from a feed stream comprising sulfur-containing compounds and dissolved metals, such as alkali metals, in a plant comprising an incineration furnace, a waste heat boiler, a dilution air heater, a dust removal absorber and an SO.sub.2 converter. The plant may further comprise a sulfuric acid condenser for the production of sulfuric acid.