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Sulphuric Acid on the WebTM Technical Manual DKL Engineering, Inc.

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Sulphuric Acid on the Web

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DKL Engineering, Inc.

Handbook of Sulphuric Acid Manufacturing
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Preface
Contents
Feedback

Sulphuric Acid Decolourization
Order Form
Preface
Table of Contents

Process Engineering Data Sheets - PEDS
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Table of Contents

Introduction

Bibliography of Sulphuric Acid Technology
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Preface
Contents

Sulphuric Acid Plant Specifications
 

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Acid Regeneration - Methyl Methacrylate (MMA) Spent Acid
February 25, 2002

Introduction
Typical Composition
Associated Links

Alkylation Spent Acid
Ammonium Sulphate Spent Acid


Introduction

Methyl methacrylate is an intermediate used in the manufacture of acrylic resin, plastics, and paints.  Most of the MMA produced in the world uses the acetone cyanohydrin (ACH) process which uses acetone as the feedstock.  ICI (UK) produces approximately 85% of the world’s supply in plants located in the UK, USA and Taiwan.

The process uses concentrated sulphuric acid as part of the catalysis system and as a carrier in the reactor train.  The MMA product is boiled of leaving an aqueous solution (spent acid) of ammonium sulphate, sulphuric acid and various organic compounds.  Approximately 3 tonnes of spent acid is produced for every tonne of MMA produced.

The relatively low sulphuric acid concentration of the spent acid makes the spent acid difficult recover economically without employing additional technology and process steps.  First the acid is preconcentrated which removes a larger portion of the water content.  This has the effect of reducing fuel consumption, furnace size and downstream plant size.  SO2 concentration is increased resulting in a smaller sulphuric acid plant contact section.

The degree of preconcentration is a function of the solubility of ammonium sulphate in solution.  It is desirable to have the solution remain as a single phase.

Oxygen enrichment is also required to achieve satisfactory economics for the process.  Varying degrees of oxygen enrichment can be done all the way to 100% oxygen.

Typical Composition

Component Formula wt%
Ammonium Sulphate (NH4)2SO4 44.4
Sulphuric Acid H2SO4 14.0
Water H2O 34.3
Ammonium Acetone Disulphonate C3N2S2H12O7 2.0
Tars as C14N2S2H35O14 3.3
Light Organics as CH3OH 0.4
Heavy Organics as C4H6O 1.4
Methacrylic Acid (Vinyl Acetate) C4H6O2 0.4