Commission Implementing Decision of 28 February 2012 establishing the best available techniques (BAT) conclusions under Directive 2010/75/EU of the European Parliament and of the Council on industrial emissions for the manufacture of glass (notified under document C(2012) 865) (Text with EEA relevance) (2012/134/EU)

GENERAL CONSIDERATIONS

Averaging periods and reference conditions for air emissions

Unless stated otherwise, emission levels associated with the best available techniques (BAT-AELs) for air emissions given in these BAT conclusions apply under the reference conditions shown in Table 1. All values for concentrations in waste gases refer to standard conditions: dry gas, temperature 273,15 K, pressure 101,3 kPa.

For discontinuous measurements	BAT-AELs refer to the average value of three spot samples of at least 30 minutes each; for regenerative furnaces the measuring period should cover a minimum of two firing reversals of the regenerator chambers
For continuous measurements	BAT-AELs refer to daily average values

Table 1

Reference conditions for BAT-AELs concerning air emissions

Activities		Unit	Reference conditions
Melting activities	Conventional melting furnace in continuous melters	mg/Nm3	8 % oxygen by volume
	Conventional melting furnace in discontinuous melters	mg/Nm3	13 % oxygen by volume
	Oxy-fuel-fired furnaces	kg/tonne melted glass	The expression of emission levels measured as mg/Nm3 to a reference oxygen concentration is not applicable
	Electric furnaces	mg/Nm3 or kg/tonne melted glass	The expression of emission levels measured as mg/Nm3 to a reference oxygen concentration is not applicable
	Frit melting furnaces	mg/Nm3 or kg/tonne melted frit	Concentrations refer to 15 % oxygen by volume. When air-gas firing is used, BAT AELs expressed as emission concentration (mg/Nm3) apply. When only oxy-fuel firing is employed, BAT AELs expressed as specific mass emissions (kg/tonne melted frit) apply. When oxygen-enriched air-fuel firing is used, BAT AELs expressed as either emission concentration (mg/Nm3) or as specific mass emissions (kg/tonne melted frit) apply
	All type of furnaces	kg/tonne melted glass	The specific mass emissions refer to 1 tonne of melted glass
Non-melting activities, including downstream processes	All processes	mg/Nm3	No correction for oxygen
	All processes	kg/tonne glass	The specific mass emissions refer to 1 tonne of produced glass

Conversion to reference oxygen concentration

The formula for calculating the emissions concentration at a reference oxygen level (see Table 1) is shown below.

Where:

E_R (mg/Nm³)

:

emissions concentration corrected to the reference oxygen level O_R

O_R (vol %)

:

reference oxygen level

E_M (mg/Nm³)

:

emissions concentration referred to the measured oxygen level O_M

O_M (vol %)

:

measured oxygen level.

Conversion from concentrations to specific mass emissions

BAT-AELs given in Sections 1.2 to 1.9 as specific mass emissions (kg/tonne melted glass) are based on the calculation reported below except for oxy-fuel fired furnaces and, in a limited number of cases, for electric melting where BAT-AELs given in kg/tonne melted glass were derived from specific reported data.

The calculation procedure used for the conversion from concentrations to specific mass emissions is shown below.

Specific mass emission (kg/tonne of melted glass) = conversion factor × emissions concentration (mg/Nm³)

Where: conversion factor = (Q/P) × 10^–6

with

Q

=

waste gas volume in Nm³/h

P

=

pull rate in tonnes of melted glass/h.

The waste gas volume (Q) is determined by the specific energy consumption, type of fuel, and the oxidant (air, air enriched by oxygen and oxygen with purity depending on the production process). The energy consumption is a complex function of (predominantly) the type of furnace, the type of glass and the cullet percentage.

However, a range of factors can influence the relationship between concentration and specific mass flow, including:

• type of furnace (air preheating temperature, melting technique)

• type of glass produced (energy requirement for melting)

• energy mix (fossil fuel/electric boosting)

• type of fossil fuel (oil, gas)

• type of oxidant (oxygen, air, oxygen-enriched air)

• cullet percentage

• batch composition

• age of the furnace

• furnace size.

The conversion factors given in Table 2 have been used for converting BAT-AELs from concentrations into specific mass emissions.

The conversion factors have been determined on the basis of energy efficient furnaces and relate only to full air/fuel-fired furnaces.

Table 2

Indicative factors used for converting mg/Nm³ into kg/tonne of melted glass based on energy efficient fuel-air furnaces

a Specific cases correspond to less favourable cases (i.e. small special furnaces with a production of generally below 100 tonnes/day and a cullet rate of below 30 %). This category represents only 1 or 2 % of the container glass production.
b Specific cases corresponding to less favourable cases and/or non-soda-lime glasses: borosilicates, glass ceramic, crystal glass and, less frequently, lead crystal glass.
Sectors		Factors to convert mg/Nm3 into kg/tonne of melted glass
Flat glass		2,5 × 10–3
Container glass	General case	1,5 × 10–3
	Specific casesa	Case-by-case study (often 3,0 × 10–3)
Continuous filament glass fibre		4,5 × 10–3
Domestic glass	Soda lime	2,5 × 10–3
	Specific casesb	Case-by-case study (between 2,5 and > 10 × 10–3; often 3,0 × 10–3)
Mineral wool	Glass wool	2 × 10–3
	Stone wool cupola	2,5 × 10–3
Special glass	TV glass (panels)	3 × 10–3
	TV glass (funnel)	2,5 × 10–3
	Borosilicate (tube)	4 × 10–3
	Glass ceramics	6,5 × 10–3
	Lighting glass (soda-lime)	2,5 × 10–3
Frits		Case-by-case study (between 5 – 7,5 × 10–3)