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.

A process for oxidizing a sulfur stream includes supplying at least one sulfur stream into a furnace; supplying oxygen-enriched combustion air into the furnace; separately supplying pure oxygen into the furnace; and at least partially oxidizing the at least one sulfur stream in the furnace. A related apparatus is also provided and includes a furnace; an inlet for supplying at least one sulfur stream into the furnace; an inlet for supplying a stream of an oxygen-enriched combustion air into the furnace; and an inlet for supplying a pure oxygen stream into the furnace separately from the supplying of the oxygen-enriched combustion air.

A process for oxidizing a sulfur stream includes supplying at least one sulfur stream into a furnace; supplying oxygen-enriched combustion air into the furnace; separately supplying pure oxygen into the furnace; and at least partially oxidizing the at least one sulfur stream in the furnace. A related apparatus is also provided and includes a furnace; an inlet for supplying at least one sulfur stream into the furnace; an inlet for supplying a stream of an oxygen-enriched combustion air into the furnace; and an inlet for supplying a pure oxygen stream into the furnace separately from the supplying of the oxygen-enriched combustion air.

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.

Improved systems and methods are disclosed for producing sulfuric acid or for producing liquefied sulfur dioxide. The systems comprise a reactor for the combustion of sulfur to sulfur dioxide, a reactor gases heat exchanger, and either a contact apparatus and absorption apparatus combination or an absorption subsystem and liquefaction apparatus combination for producing either sulfuric acid or liquid sulfur dioxide respectively. By appropriately incorporating two recycle circuits, the first after the reactor gases heat exchanger and the second after the absorption apparatus or liquefaction apparatus, several advantages can be obtained. These include reductions in equipment size, complexity, power consumption energy losses, and suppression of NOx.

Improved systems and methods are disclosed for producing sulfuric acid or for producing liquefied sulfur dioxide. The systems comprise a reactor for the combustion of sulfur to sulfur dioxide, a reactor gases heat exchanger, and either a contact apparatus and absorption apparatus combination or an absorption subsystem and liquefaction apparatus combination for producing either sulfuric acid or liquid sulfur dioxide respectively. By appropriately incorporating two recycle circuits, the first after the reactor gases heat exchanger and the second after the absorption apparatus or liquefaction apparatus, several advantages can be obtained. These include reductions in equipment size, complexity, power consumption energy losses, and suppression of NOx.

A sulfuric acid generating system can include: a primary burn chamber; an exhaust pipe extending from the burn chamber at a first end to an opposite second end; a secondary burn chamber located between the first end and second end; and a primary venturi pump having a gas inlet coupled to an outlet at the second end of the exhaust pipe and having an aqueous media inlet and having a fluid outlet. A method of producing sulfurous acid can include: providing sulfur to the primary burn chamber; burning a first portion of the sulfur in the primary burn chamber to form a first portion of sulfur dioxide; burning a second portion of the sulfur in the secondary burn chamber to form a second portion of sulfur dioxide; and mixing the first portion and second portion of sulfur dioxide with an aqueous composition so as to produce aqueous sulfurous acid.

A sulfuric acid generating system can include: a primary burn chamber; an exhaust pipe extending from the burn chamber at a first end to an opposite second end; a secondary burn chamber located between the first end and second end; and a primary venturi pump having a gas inlet coupled to an outlet at the second end of the exhaust pipe and having an aqueous media inlet and having a fluid outlet. A method of producing sulfurous acid can include: providing sulfur to the primary burn chamber; burning a first portion of the sulfur in the primary burn chamber to form a first portion of sulfur dioxide; burning a second portion of the sulfur in the secondary burn chamber to form a second portion of sulfur dioxide; and mixing the first portion and second portion of sulfur dioxide with an aqueous composition so as to produce aqueous sulfurous acid.

A novel integrated system utilizing sulfur as alternative carbon-free fuel in an ammonia primary reformer combustion zone, with co-production of sulfuric acid from concentrated SO.sub.2 off-gas stream. Such integration shall reduce hydrocarbon fuel consumption, minimize CO.sub.2 emissions, and optimize overall energy utilization.