BVT-Merkblatt zu Abwasser- und Abgasbehandlung

Annexes
sponding to the conversion efficiency values prescribed in § 4 of this article, the emissions of
SO2 and SO3 must be further reduced by alkaline scrubbing, or by means of equivalent measures.
§ 3. The wet catalytic process is allowed only with molybdenum sulphide roasting and for flue
gas desulphurisation.
§ 4. The daily average conversion rate must be at least:
1. when use is made of the single-contact process:
a) with a feed gas containing less than 6 % SO 2, a conversion rate of at least 97.5 % must
be achieved
b) with a feed gas containing 6 % SO 2 or more, a conversion rate of at least 98.5 % must be
achieved;
2. when use is made of the double-contact process:
a) with a feed gas containing less than 8 % SO 2, a conversion rate of at least 99 % must be
achieved
b) with a feed gas containing 8 % SO2 or more, a conversion rate must be achieved of at
least:
� 99.5 % with varying gas conditions
� 99.6 % with constant gas conditions;
3. when use is made of the wet catalytic process, a conversion rate of at least 97.5 % must be
achieved;
4. when any other process is used, a conversion rate must be achieved of at least 99 %.
§ 5. As a derogation from the provisions of chapter 4.4, the following emission limit values apply
for:
1. sulphur dioxide: 1700 mg/Nm 3 , without prejudice to the
conversion rate prescribed in article
5.7.5.1;
2. sulphur trioxide:
� with constant gas conditions: 60 mg/Nm 3 ;
� in the other cases: 120 mg/Nm 3 .
§ 6. In addition, in the environmental licence limit values may be imposed for the mass flow of
the SO 3 and H 2SO 4 emissions (expressed in SO 3) in the emitted waste gases.
§ 7. The conversion efficiency values indicated in § 4 of this article do not apply for SO3generators
of category 3 which are used to stimulate the emission of fly ash by the injection of
SO3 in the flue gases of heating installations. For the flue gases treated in this way, the SO3
emission standards of the corresponding heating installation apply.
Section 5.7.4 The production of nitric acid
Art. 5.7.4.1
§ 1. The provisions of this section are applicable to the nitric acid producing plants referred to
in subsection 7.1 of the classification list.
§ 2. As a derogation from the provisions of chapter 4.4, for nitrogen oxides in emitted gaseous
effluents - expressed in NO 2 - an emission limit value applies of: 450 mg/Nm 3 .
In addition, the gaseous effluents may only be emitted colourless into the ambient air. In order
to achieve this, and without prejudice to the limit value prescribed in the first paragraph, the
NO 2 emission may not exceed the value resulting from the calculation of the formula below:
NO 2 concentration =
1200
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open width of the chimney mouth in dm
Waste Water and Waste Gas Treatment 367