Number

005-EN

Section

General Section

Use

Abstract

An old paper company innovated its process for pH adjustment in the recycling process. After numerous laboratory and on-site trails, carbon dioxide was used efficiently instead of sulphuric acid.

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

skin/respiratory sensitizing
other toxic effects

Hazard Assessment

Substance to be substituted: Sulphuric acid is carcinogenic to humans (Group 1), according to the IARC Monographs and it fulfils the criteria to be listed in the Substance Database according to SUBSPORTplus Screening Criteria (SDSC). Alternative substance: Carbon dioxide (CO2) is not classified as toxic. In closed enclosures there is however the risk of suffocation by large amounts of leaked CO2. If CO2 does not come from recycled sources or was separated from the atmosphere, it contributes to the carbon footprint of the company, as it is a known greenhouse gas. Physical_hazards relating to installations using liquefied gases need to be controlled. » Check the Substance Database according to SUBSPORTplus Screening Criteria (SDSC)

Description of Substitution

The oldest paper manufacturer in North America produces paper products that conform to high technical specifications. Its paper is mostly made of cotton and other natural and synthetic fibres and the company is proud that it was used to announce the inauguration of the Statue of Liberty. The company innovated its paper reclaiming process as part of a toxic use reduction process. To reuse paper that does not meet requirements or was reclaimed from finishing operations, the paper must be reprocessed into slurry (“re-pulping”). Many papers made by the company have a high degree of permanent wet strength. This requires the use of alkalis and high temperatures, followed by a pH adjustment before reusing the slurry. The pH of the slurry used to be adjusted with sulphuric acid. The research unit of the company proposed to use carbon dioxide (CO2) instead. Initial laboratory tests were carried out at room temperature but had less than 50% efficiency. Pilot tests followed, using mobile CO2 sources and after several changes to process as well as equipment the united teams of the company and the CO2 supplier proved that the substitution was a viable option even under ambient conditions. The use of carbon dioxide as alternative to sulphuric acid improved the process control stability and reduced chemical risks. The project resulted in an overall 3% reduction in pulp production costs.

Case/substitution evaluation

The implementation of the substitution needs significant technological changes and training of operators. It eliminates the use of a very corrosive substance and the measures to manage it properly during transportation, storing and use. Hazards due to liquid CO2 need to be properly controlled. This case study shows a current substitution of a dangerous substance which is not yet state of the art, according to the BVT Information Sheet “Pulp and paper industry”.

State of implementation

In use

Enterprise using the alternative

 http://www.crane.com/

Availability ofAlternative

The substitute is available on the market but the technology needs to be readjusted to fit the needs of the application.

Type of information supplier

Authority

Other solutions

Commonwealth of Massachusetts, Executive Office of Environmental Affairs, Office of Technical Assistance (OTA) http://www.mass.gov/

Type of publication and availability

Internet presentation, freely available.

Publication source: author, company, institute, year

The description is based on the document “Crane & Company, Inc. Toxics Use Reduction Case Study Substitution with Carbon Dioxide Eliminates Major Use of Sulphuric Acid” published by the Office of Technical Assistance (OTA), a branch of the Massachusetts Executive Office of Environmental Affairs on its website in 2003.

Publication source

Type of publication and availability

http://hdl.handle.net/2452/116108

Date, reviewed

December 11, 2020