Metallgesellschaft Aktiengesellschaft

Sachtleben Chemie Gmbh

Roland Fach

Hartmut Wagner

Georg Schmidt

Egon Winkler

Volker Wichert

Ronald Apel

Gunter Okon

Klaus Engels

Peter-Bernhard Stougie

Dieter Knoblich

Edgar Czudnochowski

Stefan Leuchtenberger

Fritz Volz

Process for preparing sulphuric acid from gasses containing SO and gaseous nitrosylsulphuric acid (NO HSO or HO SONO) by contact with 94% to 98% sulphuric acid, wherein the gases flow through at least one cooler and are cooled down to 160&deg; C. to 130&deg; C. to condense out nitrosylsulphuric acid before being brought into contact with the sulphuric acid.

Process for preparing sulphuric acid from gases containing SO3 and gaseous nitrosylsulphuric acid

Nitrosylsulphuric acid is mixed in a mixing reactor with sulphuric acid saturated with SO,. The acid mixture is led into a saturating reactor into the bottom region of which water and an SO,-containing gas are introduced. The gas partially serves as stripping gas inside the saturating reactor. SO,-saturated, No,-free sulphuric acid with 5 to 60 wt % H,SO,is removed from the bottom region of the saturating reactor and part thereof is mixed with nitrosylsulphuric acid in the mixing reactor.

Process for removing NOx from nitrosylsulphuric acid

The process of concentrating a dilute sulfuric acid in a three-stage vacuum evaporation plant includes feeding an entry dilute sulfuric acid to a first evaporation stage of a vacuum evaporation plant to form an overhead vapor (6), withdrawing a finally concentrated sulfuric acid from the third evaporation stage (3), using steam or the overhead vapor (6) of the first evaporation stage as a heating fluid in the three-stage vacuum evaporation plant, maintaining the entry dilute sulfuric acid under a pressure of 0.4 to 0.7 bar and at a temperature of 80.degree. to 120.degree. C. in the first evaporation stage (1), maintaining the partially concentrated sulfuric acid under a pressure of 0.02 to 0.06 bar and at a temperature of 50.degree. to 90.degree. C. in the second evaporation stage (2), maintaining the further concentrated sulfuric acid under a pressure of 0.02 to 0.06 bar and at a temperature of 80.degree. to 120.degree. C. in the third evaporation stage (3), and condensing overhead vapors (8,8a) formed in the second and third evaporation stages. Each evaporation stage (1,2,3) includes an evaporation vessel (1b,2b,3b) and a connected recycle line including a shell-tube heat exchanger (1a,2a,3a) and pump. The process also includes continuously feeding about 30 to 95% of the entry dilute sulfuric acid (4) to the first evaporation vessel in the first evaporation stage (1) and continuously feeding the balance of the entry dilute sulfuric acid to the second evaporation vessel in the second evaporation stage (2).

Process of concentrating a dilute sulfuric acid in a three-stage

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Schermbeck, Germany

Roland Fach