Number

273-EN

Section

General Section

Use

Abstract

Bio-pitch can be mixed with char-coal to obtain electrodes. The study presents results of tests carried out with bio-pitch electrodes obtained under various conditions from eucalyptus oil.

Substituted substances

Alternative Substances

Reliability of information

Internet information: data are from an internet document and only a basic and partial evaluation could be performed

Reason substitution

CMR

Hazard Assessment

Substance to be substituted: Coal tar pitch is a classified EU carcinogen 1B, it may cause cancer Alternative substance: Bio-pitch is made from eucalyptus oil that is not known to be carcinogenic; it is not listed in the SUBSPORTplus screening criteria (SDSC) database for hazardous substances

Description of Substitution

Coal tar pitch is obtained as a by-product in coal processing and is used in various processes including manufacturing of electrodes. It has a complex composition with a high proportion of polycyclic aromatic hydrocarbons (PAHs) which are generally hold responsible for its carcinogenic effect. Research is carried on to find safer, suitable alternatives. A pilot study prepared calcined and graphited electrodes from mixtures of eucalyptus oil pitch and charcoal. Tests were made to determine their composition and compare them to electrodes made with coal or petroleum tars. The eucalyptus wood oil was obtained by slow pyrolysis at low temperatures (260 ⁰C, about 100 ⁰C lower than for coal or petroleum pitches) and reduced pressure (0.05MPa). The yield in bio pitch was around 50 %wt. The bio pitch was mixed with ground charcoal and pressed at 60MPa to obtain cylindrical electrodes that were afterwards calcined (1000⁰C) and graphited (2700⁰C). Composition analyses showed a high rate of polar compounds in the bio-pitch (80-86%) most of them monoaromatics, while in coal tar pitch polyaromatics are preponderant. Tests were made on the sample electrodes for electrical resistivity, Young’s modulus, density, porosity and other parameters. The conclusion of the study was that bio pitch may be considered as a possible alternative for coal tar pitch in electrodes.

Case/substitution evaluation

Making bio-pitch from biomass has the advantage of using renewable resources, reducing the carbon footprint and the sulphur emissions, a major contributor to acidification. The composition of bio-pitche obtained from eucalyptus is considered safer because of the low content in PAHs and by comparison with different types of eucalyptus oils (CAS 84625-32-1/ 85203-56-1) that are not known to be carcinogens but are self-classified by some sources as skin sensitisers, so handling with precaution is needed. Some companies in Brazil (where the study was made) turned to bio-oil recovery putting it on the market at a competitive price.

State of implementation

Pilot study

Date and place of implementation

pilot study in 2001, in Brasil

Availability of Alternative

pilot study

Type of information supplier

Research

Contact

J.D.Rocha, A.R.Coutinho and C.A. Luengo (2002), Biopitch Produced from Eucalyptus Wood Pyrolysis Liquids as a Renewable Binder for Carbon Electrode Manufacture, Brazilian Journal of Chemical Engineering

Type of publication and availability

Article in scientific journal, free access

Publication source: author, company, institute, year

The description is based on the article by Rocha, J.D., Coutinho, A.R., & Luengo, C.A.. (2002)' Biopitch produced from eucalyptus wood pyrolysis liquids as a renewable binder for carbon electrode manufacture', Brazilian Journal of Chemical Engineering, 19(2), 127-132.

Publication source

Type of publication and availability

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0104-66322002000200002

Date, reviewed

November 26, 2021