6 The Production Process The criteria of purity and accuracy of grade are the primary goals of sulfuric acid production. The Contact Process, described here, is almost universally used to convert SO 2 to H 2 SO 4 Weak Acid Solution 93% Acid Stream SO 2 Gas Stream 98% Acid Stream SO 3 Gas Stream Acid Pumps Quench Tower: Weak acid jets remove particulate matter from hot process gasses Scrubber: Further contact with acid jets provides additional cooling and cleaning Electrostatic Precipitators: Acid mist and remaining dust particles removed Weak Acid Pump Tank 3. The Production Process Historically, sulfuric acid production was based on the Lead Chamber Process, involving the oxidation of sulfur dioxide by nitric acid and nitrogen oxides in the presence of water. This has been replaced by the Contact Process in which sulfur dioxide is oxidized by atmospheric air at high temperatures and in the presence of a vanadium pentoxide catalyst. Specifics will vary from one plant to another, but this description is provided as an overview of a typical Contact Process. The process begins with cleaning of the gas. The sulfur dioxide from smelting and roasting operations passes through a series of gas cleaning steps that ©N No o o or r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r rF F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F Falc c c c c c c c c c c c co o o o o o o o o o o o o. B B B B B B B B B B B B B B B B B B B B B B B B B B B B B B B B B B B B B B B B B B B B B B B B B B B B B B B B B B B B By y y y y y y y y y y y y y y y r r r r r r r r r r r r e e e e e e e e e e e e e e e e e e e e ead d d d d d d d d d d d d d d d d d d d d d di i i i i i i i i i i i i i i i i i i i i i i i in n n n ng g g g g g g g t t t t t t t t t t t t th h h h h h h h h h h h h h h h h h h h h h h h h h h h h h h h h h h h hi i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i is s s s s s s s s s s s s s s s s s s s s s s s s s s s s s s s s s s s s s s s s s s s s s s s s s d d d d d d d d d d d d d d d d d d d d d d d d d d d d d d d d d d d d d d d d d d d d d d d d d d d d d d d d d d d d d do o o o o o o o o o o o o o o o o o o o o o o o o o oc c c c c c c c c c c c c c c c c c c c c c c c c c c cu u u u u u u u u u u u u u u u u u u u u u u u u u u u u u u u u u u u u u u u u u u u u u um m m m m m m m m m m m m m m m m m m m m m m m m m m m m m 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p p p p p p p p p p p p p p p p p p pr r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r ro o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o od d d d d d d d d d d d d d d d d d d d d d d d d d d d d d d d d d d d d d d d d d d d d d d d d du u u u u u u u u u u u u u u u u u u u u u u uc c c c c ce e e e e e e e e a a a a a a a a a a a a a a a a a a a a a a a a a a a an n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n ny y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y y p p p p p p p p p p p p p p p p p p p p p p p p p p p p p p p p p p p p p p p p p p p p p p p p p p p p p a a a a a a a a a a a a a a a a a a a a a ar r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r rt t t t t t t t t t t t t t t 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t t t t t t t t t t t t t t t t t t t t t t t t t t t t t t t t t t t t t t t t t t ts s s s s s s s s s s s s s s s s s s s s s s s s s s s s s s s s s s s s s s s s s s s s so o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o oe e e e e e e e e e e e e e e e e e e ev v v v v v v ve e e e e e e e er r r r w w w w wi i i i i i i i i i it t t t t t t t t t t t t t th h h h h h h h h hou u u u u u u u u u u ut t t t t t t t t t t t t t t t th h h h he e e e e e p p p p p p p p pr r r r r r r r r r r r r r r r ri i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i io o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o or r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w wr r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r ri i i i i i i i i i i i i i i i i i i i i i i i i i i i i i it t t t t t t t t t t t t t t t t t t t t t t t t t t t t tt t t t t t t t t t t t t t t t t t t t t te e e e e e e e e e e e e e e e e e en n n n n n n n n n n n n n n n n n n n n n n n c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c co o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o on n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n ns s s s s s s s s s s s s s s s s s s se e e e e e e en n n n nt t t t t t t t t t t t t t t t t t t o o o o o o o o o o o o o o of f f f f f f f f N N N N N N N N N N N N N N N No o o o o o o o o o o o o o o o o o o o o o o o o o o o or r r r r r r r r r r r r r r r r rF F F F F F F F F F F F F F F F F F Falco. The criteria accu cu cu cu cu cura ra ra ra ra racy cy cy cy cy cy of g the primary g g g go g g lf i id d d d sulfuric acid prod d d d d d d du Th T T e Contact Pro o oc o o o o e de d d d d d d d scribed he er r r re r r r r , is al al al al al al a al al al l alm m mo m st univers sa a al a a a a ly used to to to to to to to to to to to c c c c c c c con o vert SO O O O 2 2 2 2 2 2 to H 2 SO Sc crubber: Further contact with aci a d jets provides de des e des es es des des e des d additiona a a a al c l c l c l c lc c l c l c c lc c l oo ool oo o o o o o o o ing g ng ng ng g g and cl cl cl cl l cl cl cl cl c c c ea ea ea ean e ea ea ea e e e ing ng ing ing ing ng ng ng ng g ing g ng