Use of high silicon Cr Ni steel in H.sub.2 SO.sub.4 manufacture
AssigneeC-I-L Inc.
InventorsFrederick W. S. Jones, Frank Smith
Life of this patent
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Abstract
Apparatus and process for the manufacture of sulphuric acid by the contact process of the type comprising at least one gas-concentrated sulphuric acid contacting unit and a sulphuric acid heat exchanger characterized in that the contacting unit and/or heat exchanger is formed of high silicon content austenitic steel. The steel is also of use in sulphuric acid concentrators. Reduced corrosion rates are provided.
Claims19
In a process for making sulphuric acid from sulfur dioxide and oxygen in a contact process system which employs at least some sulfuric acid stream having a concentration of 90-100% and temperatures of above 40.degree. C., the improvement consisting of the use of a corrosion resistant wrought austenitic steel consisting of 17.5.+-.0.5% Cr, 17.5.+-.0.5% Ni, 4.6-5.8% Si, balance essentially Fe as as the material of construction for the portion of the system in contact with said 90-100% sulfuric acid above 40.degree. C. streams.
In a process for making sulfuric acid from sulfur dioxide and oxygen in a contact process system which employs at least some sulfuric acid stream having a concentration of 90-100% and temperature of above 40.degree. C. and one or more gas-concentrated sulfuric acid contacting units A, said unit being optionally provided with a mist eliminator B and an acid distributor C;
- a heat exchanger D;
- and a circulation system comprising a pump tank E, acid pump F and a pipe and valve system G, the improvement consisting of the use of a corrosion resistant wrought austenitic steel consisting of 17.5.+-.0.5% Cr, 17.5.+-.0.5% Ni, 4.6-5.8% Si, balance essentially Fe as the material of construction for the whole or a part of one or more of said integers A to G contact with said 90-100% sulfuric acid above 40.degree. C. streams.
In a process for concentrating sulfuric acid from a strength of at least 90% acid of the type comprising the step of heating the acid in a concentrator vessel the improvement consisting of the use of a corrosion resistant wrought austenitic steel consisting of 17.5.+-.0.5% Cr, 17.5.+-.0.5% Ni, 4.6-5.8% Si, balance essentially Fe as the material of construction for the portion of the concentrator vessel in contact with said sulfuric acid.
Dependencies are inferred from the claim text.