First draft Part II default Emission Factors, Source Group 7 Chemicals and Consumer Goods



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7 a Pulp and Paper Production


In general terms, paper is a sheet of fibers with a number of added chemicals that affect the properties and quality of the sheet. Besides fibers and chemicals, manufacturing of pulp and paper requires large amounts of process water and energy (as steam and electricity). Pulp for papermaking may be produced from virgin fiber by chemical or mechanical means or by re-pulping of recovered paper. A paper mill may utilize pulp made elsewhere (= non-integrated pulp mills) or may be integrated with the pulping operations at the same site (= integrated pulp mills). Kraft pulp mills can be both non-integrated and integrated operations, whereas sulfite pulp mills are normally integrated with paper production.

For the purpose of the Toolkit, processes can be broken down into a number of classes. Although, wood is most commonly used as raw material for pulp making, it should be noted that also non-wood fibers such as cereal straw and reeds are used as raw materials for pulp and paper production. These fibers represent 6.5-11% of the world’s virgin pulp production. In developing countries or countries with limited forestry resources, non-wood fibers make up >35% of the total pulp production (Blanco et al. 2004). One of the major producers of pulp/paper from non-wood fibers is China (Zheng et al. 2001, Zheng et al. 1997). More information on raw materials for pulp and paper manufacture can be found in the BAT&BEP Guidelines.2

The production of pulp is the major source of environmental impacts from the pulp and paper industry.

From pulp and paper mills releases of PCDD and PCDF may occur via the following vectors:



  • Emissions to air (from burning of lignin and black liquor to generate steam);

  • Emissions to air from burning wood or bark to generate steam;

  • Emissions with process water (modern pulp mills operate totally effluent free);

  • Emissions into the pulp sludge, which may be applied on land, be incinerated or landfilled;

  • Emissions into the products (= pulp, paper), which enter the market as a valuable product.

In general terms, the process to make paper and paperboard consists of three steps: pulp making, pulp processing, and paper/paperboard making. A detailed description of the process is available in the BAT&BEP Guidelines.3

Emission Factors


PCDD/PCDF emission factors are listed according to the activity type in Tables X-X. To assist in estimating releases typical values in terms of μg TEQ/ADt (Air Dry tons) are given in the tables along with typical concentrations in effluent and solids – these can be used if mass flow data are unavailable. The emission factors for the wood fiber plants assume all plants have effluent treatment facilities producing sludge and effluent low in suspended solids. For non-wood, the concentration relates to the raw effluent before treatment.

Annual emissions with wastewater effluents and pulp and paper sludges (= residues) will be calculated by multiplying the concentration in the effluent (in pg TEQ/L) or the concentration in the sludge (in μg TEQ/t dry matter) with the annual discharge or production volume, respectively.



Detailed information on how these emission factors have been derived can be found in Annex 47.4

Guidance for classification of sources

Boilers


Class 1 includes black liquor boilers.

Class 2 includes boilers for sludge and biomass/bark.

Effluents and pulp sludges, pulp and paper products


Class 1 refers to the Kraft process, based on Cl2 gas, non-wood fibers potentially impacted by PCP.

Class 2 refers to the Kraft process, based on old technology (Cl2).

Class 3 refers to the mixed technology (TCF but Cl2 partially in 1st step).

Class 4 refers to sulfite papers, based on old technology (free chlorine).

Class 5 refers to the Kraft process, based on modern technology (ClO2).

Class 6 refers to sulfite papers, based on new technology (ClO2, TCF).

Class 7 refers to thermo-mechanical pulp.

Class 8 refers to recycling paper from contaminated waste paper.

Class 9 refers to recycling paper from modern papers.
Table X: PCDD/PCDF emission factors for the pulp and paper industry: boilers


7 a

Pulp and Paper Production

Emission factors - µg TEQ/ ADt pulp

Emission factors - µg TEQ/ t ash




Classification

Air

Residue

1

Black liquor boilers

0.07

NA

2

Boilers for sludge and biomass/bark

0.2

50

Table X: PCDD/PCDF emission factors for effluents and pulp sludges


7 a

Pulp and Paper Production

Emission factors

Water

Emission factors

Residue = Sludge




Classification

µg TEQ/ ADt pulp

pg TEQ/L

µg TEQ/ ADt pulp

µg TEQ/t in Sludge

1

Kraft process, Cl2 gas, non-wood fibers, PCP-treated

ND

300

ND

ND

2

Kraft process, old technology (Cl2)

4.5

70

4.5

100

3

Mixed technology (TCF but Cl2 partially in 1st step)

1.0

15

1.5

30

4

Sulfite papers, old technology (free

chlorine)















5

Kraft process, modern technology (ClO2)

0.06

2

0.2

10

6

Sulfite papers, new technology (ClO2, TCF)













7

Thermo-mechanical pulp

ND

ND

ND

ND

8

Recycling paper from contaminated waste paper*




30







9

Recycling paper from modern papers

ND

ND

ND

ND

* Wastewater from deinking system

Table X: PCDD/PCDF emission factors for pulp and paper products


7 a

Pulp and Paper Production

Emission factors - µg TEQ/ t of product




Classification

1

Kraft pulps from non-wood fibers, potentially impacted by PCP, Cl2 gas bleaching

30

2

Kraft pulps and papers from primary fibers, free chlorine bleaching

8

3

Mixed technology (TCF but Cl2 partially in 1st step)

3

4

Sulfite papers, old technology (free chlorine)

1

5

Kraft papers, new technology (ClO2, TCF), unbleached papers

0.5

6

Sulfite papers, new technology (ClO2, TCF)

0.1

7

Thermo-mechanical pulp

1

8

Recycling paper from contaminated waste paper

10

9

Recycling paper from modern papers

3


Activity rates


Data for pulp are commonly reported based on Air Dried tons (ADt), which refer to pulp at 90% dryness or 900 kg of bone dry pulp. For paper, the basis is the finished paper at the dryness that results, typically 94-96% dryness. Activity rates may be obtained from various sources, in particular:

  • Owners/operators of the relevant facilities (by questionnaires);

  • State, provincial, national and/or international agencies that gather centralized statistical information.


Uncertainty


Letter data quality rating is provided for the default emission factors



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