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Chapter 5: Solvent and other product use
5.1 Sector overview (CRF 3)
This sector includes emissions from chemical cleaning substances used in dry-cleaning, printing, metal degreasing and from the use of paints, lacquers, thinners and related materials. The emissions arise from the evaporation of the volatile chemicals when solvent-based products are exposed to air.
In 2006, emissions from the “solvent and other product use” sector comprised 40.3 Gg of NMVOC. This is a decrease of 1.2 Gg (3.0 per cent) from 41.5 Gg in 1990. The categories dominating the sector are NMVOC emissions from “paint application” and “other domestic and commercial use” (Figure 5.1.1).
Figure 5.1.1 Change in emissions of NMVOC from the solvent and other product use sector from 1990 to 2006 (all figures Gg NMVOC)
See figure at its full size (including text description). In 2006, N2O emissions from anaesthesia use totalled 0.13 Gg N2O or 40.3 Gg CO2-e. There has been no change from 1990 when emissions from anaesthesia totalled 0.13 Gg N2O.
5.1.1 Description
Ethanol and methanol are the only solvents produced in New Zealand and the majority of both products are exported. All other solvents are imported, including some ethanol and methanol (for quality and price reasons).
5.1.2 Methodological issues
Detailed methodologies for emissions from solvents and other product use are not provided in the revised 1996 IPCC guidelines (IPCC, 1996). Two basic approaches for estimating emissions: consumption and production-based estimates are documented. The IPCC guidelines note that for many applications of solvents, the end uses are too small-scale, diverse and dispersed to be tracked directly. Therefore, emission estimates are generally based on total consumption and an assumption that once these products are sold to end users, they are applied and emissions produced relatively rapidly. For most surface coating and general solvent use, this approach is recommended. The New Zealand inventory estimates solvent emissions with a consumption-based approach. Activity data is obtained by an industry survey (CRL Energy Limited, 2006). Details of emission estimates for solvent and other product use are included in the excel workbooks available for download with this report from the Ministry for the Environment’s website.
Emission factors are developed based on the likely final release of NMVOC to the atmosphere per unit of product consumed. The emission factors are applied to sales data for the specific solvent or paint products. The subcategories of solvents and other products specified in the common reporting format are detailed below.
Paint application
Consumption and emissions from paints and thinners are based on information from Nelson (1992) and the Auckland Regional Council (1997). Additional activity data for 1993 to 1996 was provided by the New Zealand Paint Manufacturers Association.
Degreasing and dry-cleaning
Most dry-cleaners in New Zealand use perchloroethylene and a small number use white spirits. Trichloroethylene has never been used in dry-cleaning but it is used in degreasing, for instance in the leather manufacturing industry. In general, solvent losses from the dry-cleaning industry have reduced substantially as closed circuit machines and refrigerated recovery units are increasingly used. Consumption of perchloroethylene and trichloroethylene are assumed to equal the volume of imports. Import data is supplied by Statistics New Zealand.
Chemical products (manufacturing and processing)
The solvents tetrabutyl urea and alkyl benzene are used in the production of hydrogen peroxide. Emissions of NMVOCs are provided by Degussa Peroxide Limited. The hydrogen peroxide plant has an on-line, continuous, activated-carbon solvent recovery system. Solvent losses are recorded annually as the difference between input solvent and solvent collected for incineration.
Losses of ethanol (and other minor components such as methanol, acetaldehyde and ethyl acetate) are monitored in the three ethanol plants in New Zealand. Using these values, an emission factor for NMVOC of 6 g/litre has been calculated. Ethanol used for alcoholic beverage production has been reported under food and drink production in the industrial processes sector.
Other – printing ink use
There is one major printing ink company in New Zealand with approximately 50 per cent of the solvent ink market share. The company provided a breakdown on the type of ink used. Approximately 50 per cent of inks used are oil inks (paste inks) which contain high boiling temperature oils. These are evaporated off during “heat setting” but the volatiles are generally treated in a solvent burner that minimises emissions. The remaining 50 per cent of inks are liquid of which 60 per cent are solvent inks (the remaining 40 per cent are water based).
Other – aerosols
Approximately 25 million aerosol units are sold in New Zealand each year. The average propellant charge is 84 grams and 95 per cent are hydrocarbon-based, total NMVOC emissions in 2006 were 2.0 Gg. This is based on the assumptions that the units are fully discharged within two years of purchase.
Other – domestic and commercial use
This category includes NMVOC emissions from domestic and commercial solvent use in the following areas: household products, toiletries, rubbing compounds, windshield washing fluids, adhesives, polishes and waxes, space deodorants, and laundry detergents and treatments. Emissions for this category are based on a per capita emission factor. The emission factor used is 2.54 kg NMVOC/capita/yr (United States EPA, 1985). It is assumed that the emissions rate per capita derived by the United States Environmental Protection Agency is applicable to the average product use in New Zealand (CRL Energy Limited, 2006). Population data is from the Statistics New Zealand website.
N2O for anaesthesia
Activity data for 2006 were obtained from the sole importer of bulk N2O into New Zealand. The importer supplies its competitor with its requirements so the figure represents full coverage of N2O use in New Zealand. Most of the N2O is used for anaesthesia and the production of Entonox (a half-and-half mixture of nitrous oxide and oxygen for pain relief). There is a very small amount used in motor sports and in scientific analysis.
5.1.3 Uncertainties and time-series consistency
Estimates of uncertainty are based on information provided by industry in the questionnaires and discussions with respondents (CRL Energy Limited, 2006). The overall uncertainties are shown in Table 5.1.1
Table 5.1.1 Uncertainties in “solvent and other product use” (CRL Energy Limited, 2006)
| HFC source | Uncertainty estimates |
|---|---|
|
Paint application |
Combined uncertainty ± 40% |
|
Degreasing/dry-cleaning |
Combined uncertainty ± 30% |
|
Chemical products |
Combined uncertainty ± 20% |
|
Printing |
Combined uncertainty ± 50% |
|
Aerosols |
Combined uncertainty ± 20% |
|
Domestic/commercial use |
Combined uncertainty ± 60% |
|
Anaesthesia (N 2 O) |
Combined uncertainty ± 10% |
5.1.5 Source-specific recalculations
The 2007 industrial processes survey (CRL Energy Limited, 2007) revealed some inconsistencies in the activity data for nitrous oxide use in New Zealand for the period 2002–2005. Using the latest activity data for the period was updated by linear interpolation.
5.1.6 Source-specific planned improvements
There are no planned improvements for this sector. There are large uncertainties, however the emission levels from the solvents and other products sector are negligible compared with other sectors. In accordance with good practice, New Zealand will continue to focus its inventory development on key source categories (IPCC, 2000).
