Method for apparatus for treating sulfur dioxide containing gasses

A method comprising:

• (a) obtaining a first gas stream containing a first concentration of sulfur dioxide from a first source of sulfur dioxide;
• (b) subjecting the first gas stream to catalysis to produce a first treated gas stream containing sulfur trioxide and sulfur dioxide;
• (c) obtaining a second gas stream containing a second concentration of sulfur dioxide from a second source of sulfur dioxide;
• and,
• (d) subjecting the first treated gas stream and the second gas stream together to catalysis to produce a second treated gas stream containing sulfur trioxide and sulfur dioxide.

An apparatus comprising:

• (a) a first catalyst bed;
• (b) a first gas stream passage positioned upstream from the first catalyst bed and connecting in fluid flow communication a first source of sulfur dioxide with the first catalyst bed;
• (c) a second catalyst bed positioned downstream from the first catalyst bed;
• (d) a treated gas passage connecting the first and second catalyst beds in fluid flow communication;
• and,
• (e) a second gas stream passage positioned upstream from the second catalyst bed and connecting in fluid flow communication a second source of sulfur dioxide with the second catalyst bed.

An apparatus comprising:

• (a) a first catalyst bed;
• (b) a first gas stream passage positioned upstream from the first catalyst bed and in fluid flow communication with the first catalyst bed, the first gas stream passage providing sulfur dioxide to the first catalyst bed, the first catalyst bed having a volume of catalyst which does not limit conversion of sulfur dioxide to sulfur trioxide;
• (c) a second catalyst bed positioned downstream from the first catalyst bed;
• (d) a treated gas passage connecting the first and second catalyst beds in fluid flow communication;
• and,
• (e) a second gas stream passage positioned upstream from the second catalyst bed and in fluid flow communication with the second catalyst bed, the second gas stream passage providing sulfur dioxide, which has not passed through the first catalyst bed, to the second catalyst bed.