Commercial production of sulfuric acid is almost entirely accomplished nowadays using the contact process. And the trend is to increase conversion efficiency and reduce emissions of unconverted sulfur dioxide. By using a special combination of contact catalyst beds, a single contact single absorption (SCSA) system can be engineered to achieve the conversion and emission capabilities of conventional double contact double absorption systems. Thus, the complexity and cost of incorporating a second absorption tower and associated heat exchanger in the system can be omitted. In the SCSA system, the initial catalyst bed or beds comprise vanadium oxide catalyst and the last catalyst bed or beds comprise platinum catalyst operating at a much lower temperature than the initial beds.

Commercial production of sulfuric acid is almost entirely accomplished nowadays using the contact process. And the trend is to increase conversion efficiency and reduce emissions of unconverted sulfur dioxide. By using a special combination of contact catalyst beds, a single contact single absorption (SCSA) system can be engineered to achieve the conversion and emission capabilities of conventional double contact double absorption systems. Thus, the complexity and cost of incorporating a second absorption tower and associated heat exchanger in the system can be omitted. In the SCSA system, the initial catalyst bed or beds comprise vanadium oxide catalyst and the last catalyst bed or beds comprise platinum catalyst operating at a much lower temperature than the initial beds.

Power is provided to an electrochemical cell. The electrochemical cell includes an anode side and a cathode side. A solution is flowed to the anode side. The solution includes hydrogen sulfide dissolved in water. Water is flowed to the cathode side. The water flowed to the cathode side can be in the form of steam. Providing power to the electrochemical cell facilitates production of sulfur dioxide on the anode side. Providing power to the electrochemical cell facilitates production of hydrogen on the cathode side. A membrane separating the anode side from the cathode side prevents flow of hydrogen sulfide, water, and sulfur dioxide from passing through the membrane while allowing hydrogen cations and oxygen anions to pass through the membrane. Sulfur dioxide is flowed out of the anode side. Hydrogen is flowed out of the cathode side.

Power is provided to an electrochemical cell. The electrochemical cell includes an anode side and a cathode side. A solution is flowed to the anode side. The solution includes hydrogen sulfide dissolved in water. Water is flowed to the cathode side. The water flowed to the cathode side can be in the form of steam. Providing power to the electrochemical cell facilitates production of sulfur dioxide on the anode side. Providing power to the electrochemical cell facilitates production of hydrogen on the cathode side. A membrane separating the anode side from the cathode side prevents flow of hydrogen sulfide, water, and sulfur dioxide from passing through the membrane while allowing hydrogen cations and oxygen anions to pass through the membrane. Sulfur dioxide is flowed out of the anode side. Hydrogen is flowed out of the cathode side.

A process for preparing sulfuric acid may involve melting elemental sulfur in a melting stage to give molten sulfur. Sulfuric acid is subsequently produced from the molten sulfur. Further, sulfur-containing offgases formed in the melting stage may be subjected to oxidation in a supplementary oxidation stage in which sulfur-containing components of the offgases are oxidized to sulfur dioxide. The process may further involve processing the sulfur dioxide to give at least one reaction product. The melting stage may be operated without emissions by processing all of the offgases from the melting stage. An apparatus may be employed for carrying out such a process.

A process for preparing sulfuric acid may involve melting elemental sulfur in a melting stage to give molten sulfur. Sulfuric acid is subsequently produced from the molten sulfur. Further, sulfur-containing offgases formed in the melting stage may be subjected to oxidation in a supplementary oxidation stage in which sulfur-containing components of the offgases are oxidized to sulfur dioxide. The process may further involve processing the sulfur dioxide to give at least one reaction product. The melting stage may be operated without emissions by processing all of the offgases from the melting stage. An apparatus may be employed for carrying out such a process.

The invention relates to shaped catalyst bodies for the oxidation of SO.sub.2 to SO.sub.3, which comprise vanadium, at least one alkali metal and sulfate on a silicon dioxide support material, wherein the shaped body has the shape of a cylinder having 3 or 4 hollow-cylindrical convexities, obtainable by extrusion of a catalyst precursor composition comprising vanadium, at least one alkali metal and sulfate on a silicon dioxide support material through the opening of an extrusion tool, wherein the opening of the extrusion tool has a cross section formed by 3 or 4 partly overlapping rings whose midpoints lie essentially on a circular line having a diameter of y, wherein the rings are bounded by an outer line lying on a circle having an external diameter x1 and an inner line lying on a circle having an internal diameter x2.

The invention relates to shaped catalyst bodies for the oxidation of SO.sub.2 to SO.sub.3, which comprise vanadium, at least one alkali metal and sulfate on a silicon dioxide support material, wherein the shaped body has the shape of a cylinder having 3 or 4 hollow-cylindrical convexities, obtainable by extrusion of a catalyst precursor composition comprising vanadium, at least one alkali metal and sulfate on a silicon dioxide support material through the opening of an extrusion tool, wherein the opening of the extrusion tool has a cross section formed by 3 or 4 partly overlapping rings whose midpoints lie essentially on a circular line having a diameter of y, wherein the rings are bounded by an outer line lying on a circle having an external diameter x1 and an inner line lying on a circle having an internal diameter x2.

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.