Purification of gas containing sulfur dioxide or sulfur trioxide with the production of elemental sulfur

Claim 2

A PROCESS FOR PURIFYING A SULFUR DIOXIDE CONTAINING GAS BY MEANS OF AN AQUEOUS SOLUTION OF SODIUM CARBONATE AND WITH THE PRODUCTION OF ELEMENTAL SULFUR, COMPRISING THE STEPS OF (A) CONTACTING SAID GAS WITH AN AQUEOUS SOLUTION OF SODIUM CARBONATE SO AS TO DISSOLVE SAID SULFUR DIOXIDE IN THE FORM OF SODIUM SULFITE; (B) CONTACTING THE RESULTING SOLUTION WITH AN AQUEOUS SOLUTION OF AMMONIUM HYDROGEN CARBONATE OR A GASEOUS MIXTURE OF CARBON DIOXIDE AND AMMONIA SO AS TO FORM A MIXTURE OF A SODIUM HYDROGEN CARBONATE PRECIPITATE AND A LIQUID PHASE, SEPARATING SAID PRECIPITATE AND HEATING IT TO FORM CARBON DIOXIDE AND SODIUM CARBONATE, SEPARATING SAID CARBON DIOXIDE FROM SAID SODIUM CARBONATE, RECYCLING SAID CARBON DIOXIDE TO STEP (B) AND SAID SODIUM CARBONATE TO STEP (A); (C) REACTING SAID LIQUID PHASE OR ITS VAPORIZATION PRODUCTS WITH HYDROGEN SULFIDE TO PRODUCE SULFUR AND RELEASE A NH3 CONTAINING GAS, SEPARATING THE SULFUR AND RECYCLING THE NH3 CONTAINING GAS TO STEP (B).

Claim 3

A process according to claim 1, wherein the step (a) is carried out at a tEmperature of from 50* to 80*C. and the step (b) at a temperature of from 0* to 50*C.

Claim 4

A process according to claim 1, wherein the NH3 containing gas and the carbon dioxide are converted to ammonium hydrogen carbonate prior to being recycled to step (b).

Claim 5

A process according to claim 1, wherein additional carbon dioxide gas is supplied to step (b).

Claim 6

A process according to claim 1, wherein said sulfur dioxide containing gas also contains sulfuric anhydride.

Claim 7

A process according to claim 1, wherein said reacting of step (c) is carried out at 90*-170*C.

Claim 8

A process according to claim 1, wherein said liquid phase is reacted in step (c).

Claim 9

A process according to claim 1, wherein said vapor phase is reacted in step (c).

Claim 10

A process according to claim 1, wherein said gaseous mixture of carbon dioxide and ammonia is employed in step (b).

Claim 11

A process according to claim 6, wherein said reacting of step (c) is conducted with said vaporization products in contact with a member selected from the group consisting of a glycol, a glycol ester, a glycol ether, a polyalkylene glycol, a polyalkylene glycol ester, a polyalkylene glycol ether, a heavy alcohol, a phosphoric ester, N-methyl pyrrolidone and molten sulfur.

Claim 12

A process according to claim 1, wherein the resultant solution of sodium sulfite in step (a) is reacted with hydrogen sulfide before being subjected to step (b).

Claim 13

A process for purifying a hydrogen sulfide containing gas by means of an aqueous solution of sodium carbonate and with the production of elemental sulfur, comprising the steps of (a) contacting said gas with an aqueous solution of sodium carbonate so as to dissolve said hydrogen sulfide in the form of sodium sulfide; (b) contacting the resulting solution with an aqueous solution of ammonium hydrogen carbonate or a mixture or carbon dioxide and ammonia so as to form a mixture of a sodium hydrogen carbonate precipitate and a liquid phase, separating said precipitate and heating it to form carbon dioxide and sodium carbonate, separating said carbon dioxide from said sodium carbonate, recycling said carbon dioxide to step (b) and said sodium carbonate to step (a); (c) heating said liquid phase so as to release a gas containing H2S and NH3 therefrom; (d) reacting said H2S and NH3 containing gas with sulfur dioxide to produce sulfur and release a NH3 containing gas, separating the sulfur and recycling the NH3 containing gas to step (b).

Claim 14

A process for purifying a hydrogen sulfide containing gas by means of an aqueous solution of sodium carbonate and with the production of elemental sulfur, comprising the steps of (a) contacting said gas with an aqueous solution of sodium carbonate so as to dissolve said hydrogen sulfide in the form of sodium sulfide; (b) contacting the resulting solution with an aqueous solution of ammonium hydrogen carbonate or a mixture or carbon dioxide and ammonia so as to form a mixture of a sodium hydrogen carbonate precipitate and a liquid phase, separating said precipitate and heating it to form carbon dioxide and sodium carbonate, separating said carbon dioxide from said sodium carbonate, recycling said carbon dioxide to step (b) and said sodium carbonate to step (a); (c) heating said liquid phase so as to release a gas containing H2S and NH3 therefrom; (d) reacting said H2S and NH3 containing gas with sulfur dioxide to produce sulfur and release a NH3 containing gas, separating the sulfur and recycling the NH3 containing gas to step (b).

Claim 15

A process according to claim 12, wherein the step (a) is carried out at a temperature of from 50* to 80*C. and the step (b) at a temperature of from 0* to 50*C.

Claim 16

A process according to claim 12, wherein the NH3 containing gas and the carbon dioxide are converted to ammonium hydrogen carbonate prior to being recycled to step (b).

Claim 17

A process according to claim 12, wherein additional carbon dioxide gas is supplied to step (b).

Claim 18

A process according to claim 12, wherein said reacting of step (c) is carried out at 90*-170*C.

Claim 19

A process according to claim 12, wherein said liquid phase is reacted in step (c).

Claim 20

A process according to claim 12, wherein said vapor phase is reacted in step (c).

Claim 21

A process according to claim 12, wherein said gaseous mixture of carbon dioxide and ammonia is employed in step (b).

Claim 22

A process according to claim 16, wherein said reacting of step (c) is conducted with said vaporization products in contact with a member selected from the group consisting of a glycol, a glycol ester, a glycol ether, a polyalkylene glycol, a polyalkylene glycol ester, a polyalkylene glycol ether, a heavy alcohol, a phosphoric ester, N-methyl pyrrolidone and molten sulfur.

Claim 23

A process according to claim 12, wherein the aqueous sodium carbonate solution also contains sodium hydroxide.