Systems and methods for producing sulfuric acid or liquefied sulfur dioxide

A system for the production of sulfur dioxide liquid comprising:

• a reactor for the combustion of sulfur to sulfur dioxide comprising an inlet for a supply of sulfur, an inlet for a supply of oxygen at ≥90% purity by volume, a recycle inlet for recycle gases, and an outlet for reactor outlet gases comprising sulfur dioxide;
• a reactor gases heat exchanger for cooling reactor outlet gases comprising an inlet fluidly connected to the reactor outlet and an outlet for cooled reactor outlet gases;
• an absorption subsystem comprising an absorption apparatus for absorbing sulfur trioxide into sulfuric acid to form more concentrated sulfuric acid, wherein the absorption subsystem comprises an inlet fluidly connected to the reactor gases heat exchanger outlet, an outlet for unabsorbed reactor outlet gases, and an outlet for the concentrated sulfuric acid;
• a liquefaction apparatus for the conversion of sulfur dioxide gas to sulfur dioxide liquid comprising an inlet connected to the absorption subsystem outlet, an outlet for liquefaction apparatus gases, and an outlet for liquid sulfur dioxide;
• a first recycle circuit comprising a first pump and fluidly connecting the reactor gases heat exchanger outlet to the recycle inlet of the reactor;
• and
• a second recycle circuit comprising a second pump and fluidly connecting the outlet of the liquefaction apparatus for liquefaction apparatus gases to the recycle inlet of the reactor.