ECOPROFILE OF HYDROGEN PEROXIDE

ECOPROFILE OF HYDROGEN PEROXIDE I Boustead & M Fawer A report for the Peroxygen Sector Group of CEFIC December 1996 1 CONTENTS PREFACE ............
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ECOPROFILE OF HYDROGEN PEROXIDE

I Boustead & M Fawer

A report for the Peroxygen Sector Group of CEFIC

December 1996

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CONTENTS PREFACE ................................................................................................................................. 4 1. INTRODUCTION ................................................................................................................ 5 2. USES OF HYDROGEN PEROXIDE ................................................................................. 5 3. PRODUCTION PROCESS ................................................................................................. 5 4. DATA SOURCES................................................................................................................. 7 5. ECOPROFILE RESULTS .................................................................................................. 8 5.1. ENERGY ................................................................................................................................ 8 5.2. PRIMARY FUELS ..................................................................................................................... 9 5.3. AIR EMISSIONS ..................................................................................................................... 10 5.4. WATER EMISSIONS ............................................................................................................... 11 5.5. SOLID WASTE ....................................................................................................................... 12 5.6. RAW MATERIALS................................................................................................................... 13 APPENDIX 1 - ECOPROFILE METHODOLOGY .......................................................... 14 A1. INTRODUCTION ........................................................................................................... 14 A2. OVERVIEW OF ECOPROFILE METHODOLOGY ................................................ 14 A3. IMPACTS AND INVENTORIES .................................................................................. 15 A4. INDUSTRIAL SYSTEMS .............................................................................................. 17 A5. INDUSTRIAL NETWORKS ......................................................................................... 19 A6. THE NATURE OF EXTENDED SYSTEMS ............................................................... 21 A7. FUELS AND ENERGY .................................................................................................. 22 A8. THE FUEL PRODUCING INDUSTRIES .................................................................... 23 A9. DESCRIBING THE PERFORMANCE OF A SYSTEM ............................................ 26 A10. CO-PRODUCT ALLOCATION.................................................................................. 27 A10.1. GENERAL PRINCIPLES ...................................................................................................... 27 A10.2. CO-PRODUCT ALLOCATION USING MASS ........................................................................... 27 A10.3. STOICHIOMETRIC PARTITIONING ...................................................................................... 29 A10.4. HYBRID ALLOCATION ....................................................................................................... 31 A11. CALCULATION ASSUMPTIONS ............................................................................. 31 A11.1. STEAM CO-PRODUCT ....................................................................................................... 32 A11.2. STEAM CONDENSATE ....................................................................................................... 33 A11.3. CO-GENERATION OF STEAM AND ELECTRICITY .................................................................. 33 A11.4. WASTE INCINERATION ...................................................................................................... 34

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A12. CALCULATING AVERAGES .................................................................................... 34 A13. PRESENTATION OF RESULTS ................................................................................ 37 A13.1. DATA CATEGORIES .......................................................................................................... 37 A13.2. ENERGY DATA ................................................................................................................. 38 A13.3. EMISSION DATA ............................................................................................................... 41 A13.4. RAW MATERIALS INPUTS ................................................................................................... 41 A14. INTERPRETING RESULTS ....................................................................................... 41

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PREFACE Eco-profiles are building blocks for use in life-cycle assessment (LCA) studies. While LCA’s are often described as ‘Cradle to grave’ studies, ecoprofiles, of the type reported here, can be regarded as ‘Cradle to gate’ studies and form an essential input to LCA’s. As with LCA’s, ecoprofiles take into account materials and energy inputs and outputs in the form of emissions to land, air and water. This report has been developed under an initiative of the CEFIC Peroxygen Sector Group in order to respond to the general increasing concern of the environmental impact of the production process for hydrogen peroxide and to provide accurate, industry-based information for use by external researchers needing data on the production of hydrogen peroxide. The report has been produced as a collaborative exercise between Dr Ian Boustead (Boustead Consulting Ltd, U.K.) and Dr Matthias Fawer (EMPA The Swiss Federal Laboratories for Materials Testing and Research), two independent experts in ecoprofile analysis.

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1. INTRODUCTION Hydrogen peroxide, H2O2, was first discovered by Thenard among others in 1818 by reacting acids with barium peroxide, BaO2. He called it oxygenated water, recognising that, relative to hydrogen, it contained twice as much oxygen as water. It resembles water in appearance being colourless in small quantities but blue when observed in thick layers. It decomposes to oxygen and water and this decomposition is promoted by heat and alkalis. Commercial grade H2O2 usually contains small amounts of stabilizers.

2. USES OF HYDROGEN PEROXIDE Hydrogen peroxide is a strong oxidising agent and is widely used as a bleaching agent. In dilute solutions it is an efficient antiseptic. The uses of hydrogen peroxide have been changing in recent years as shown in Table 1. Table 1 Changing end uses of hydrogen peroxide. 1991 Textile bleaching 15.4% Chemical production 17.5% Wood pulp bleaching 56.5% Environmental uses 3.8% Miscellaneous uses 6.8%

1995 9.3% 14.9% 65.7% 3.0% 7.1%

3. PRODUCTION PROCESS Hydrogen peroxide is produced by reducing alkyl anthraquinones with hydrogen in the presence of a catalyst to the hydroquinone. After the catalyst has been removed to prevent decomposition of the hydrogen peroxide, the hydroquinone is oxidised, usually with air, back to quinone with a resultant co-production of hydrogen peroxide. The reaction scheme is of the form:

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O

OH R

R

+ H2 OH

O alkylanthraquinone

alkylhydroanthraquinone

O

OH R

R

+ O2

OH

+ H 2O 2

O

The hydrogen peroxide is removed and purified and the quinone is regenerated and returned to the reaction. The anthraquinone must be dissolved in a suitable solvent for the hydrogenation, oxidation and extraction reactions - this is usually referred to as the working solution. The solvent is usually a mixture because quinones dissolve readily in non-polar aromatic solvents, such as benzene and its derivatives, whereas hydroquinones dissolve well in polar solvents, such as alcohols and esters. A variety of different mixtures are in use but the aim is to satisfy a number of criteria, namely good solubility of both quinone and hydroquinone, good stability in both hydrogenator and oxidiser, low solubility in water and aqueous hydrogen peroxide solutions, sufficiently higher density than water to ensure separation of the two phases during extraction, low volatility, high distribution coefficient for hydrogen peroxide in the solventwater system and low toxicity.1 In the hydrogenator, the working solution is reacted with hydrogen in the presence of a catalyst. The process is exothermic and the heat of reaction is removed by cooling the working solution before it enters the hydrogenator, by cooling the reactor during hydrogenation and/or by cooling the hydrogenated working solution. After the hydrogenation reaction, the working solution must pass through a filtration stage to remove all traces of catalyst. Even small traces of catalyst in the oxidation and extraction stages leads to significant losses of hydrogen peroxide and could present safety problems. During the oxidation stage, air is passed through the hydrogenated working solution to convert the dissolved

1 Goor, G., Kunkel, W & Weiberg, O. Hydrogen Peroxide. In Ullman’s Encyclopedia of Industrial Chemistry. VCH Publishers.

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hydroquinones to quinones and form the hydrogen peroxide. The air outlet is passed over activated carbon adsorbers to recover solvent. Crude hydrogen peroxide is extracted from the oxidised working solution by treating with water. The working solution is then regenerated and fed back to the front of the process and the crude hydrogen peroxide (15-35 wt%) is fed to a treatment unit where the concentration is increased to 50-70 wt%. 4. DATA SOURCES The data used in the calculations leading to the results reported here were derived from four main sources. 1. Information on the production of hydrogen peroxide was supplied by nine plants in Belgium, Finland, France, Germany, Italy, Spain, Sweden and the United Kingdom. Most of these producers manufactured their own hydrogen using the reformer process but some use some electrolytic hydrogen. Information on the production of alkyl anthraquinone was provided by the principal producer in Europe. 2. Information on some chemical intermediates were derived from earlier work carried out for CEFIC and APME. 3. Information on the production of fuels and energy have been derived from the reports of the International Energy Agency.2,3,4 4. Data for supporting operations and transport have been obtained from other manufacturers and operators as part of an on-going exercise involved in maintaining a data-base for LCA calculations. No process data other than the fuel data noted above have been derived from the literature. The reliability of the data tables in this report inevitably depends upon the quality of the information supplied by individual operators. It is possible to carry out a number of elementary checks on quality such as checking mass and energy balances and ensuring that the data do not violate any of the basic physical laws. However, beyond these checks, the data quality is dependent on the quality of the records maintained by individual companies. The detail of 2

International Energy Agency. Coal Information 1994. ISBN 92-64-14530-3. OECD Paris 1995. 3 International Energy Agency. Oil and gas information 1994. ISBN 92-64-04494-9. OECD, Paris, 1995. 4 International Energy Agency. Electricity information 1994. ISBN 92-64-14547-8. OECD Paris, 1995.

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all calculations were referred back to individual companies before being incorporated into the final average to ensure that all information was transcribed correctly and that any anomalies were corrected.

5. ECOPROFILE RESULTS This section presents the results of the ecoprofile calculations. The background to ecoprofile calculations in general, the specific assumptions used in this work and some guidance on the interpretation of the tables are given in Appendix 1. 5.1. Energy The gross or cumulative energy associated with the production, of purified hydrogen peroxide is shown in Table 2. Table 2 Gross energy associated with the production of 1 kg of purified hydrogen peroxide. Fuel type Electricity/MJ Oil fuels/MJ Other fuels/MJ Total/MJ

Production & delivery 6.52 0.21 0.68 7.40

Delivered energy 2.91 1.30 11.09 15.30

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Transport 0.03 0.03 0.01 0.08

Feedstock energy 0.00 0.14 0.07 0.22

Total energy 9.46 1.68 11.86 23.00

5.2. Primary fuels The cumulative primary fuel and feedstock requirements for the production of hydrogen peroxide is given in Table 3. Table 3 Gross primary energy associated with the production of 1 kg of purified hydrogen peroxide. (Totals may not agree because of rounding) Coal Oil Gas Hydro Nuclear Lignite Wood Sulphur Hydrogen Recovered Peat Total

Fuel production 2.13 0.92 0.94 0.42 2.58 0.29 0.02