Low-temperature desulfurization (DeSOx)

DeSOx System Low-temperature desulfurization

All data in enclosure passport.
Price on request.

Description:
Low-temperature desulfurization (DeSOx) system for boilers K8, K9, K10, and K11 at the heating plant operated by TAMEH Czech s.r.o. (now Vitkovice Energy s.r.o.).

Key Details:
Purpose: Removal of sulfur oxides (SOx) from flue gases at low temperatures.

Coverage: Installed on boilers K8, K9, K10, and K11.

1. Equipment description

1.1 Basic data and functional characteristics

The desulphurisation plant is used to reduce emissions of SO2 and particulate matter from the flue gases of boilers K8 (100 t/h steam), K9 (200 t/h steam), K10 (200 t/h steam), K11 (230 t/h steam). The desulphurisation building is connected to the outlets of the existing smoke fans behind the electrostatic precipitators of boilers K8 to K11 by new flue pipes.

The key component of the desulphurisation process, using the so-called semi-dry method, is the 2 vertical fluidised bed absorbers, consisting essentially of a large diameter high cylindrical upper section and a small diameter and much shorter cylindrical lower section, the two cylindrical sections being connected by a transition piece in the form of a venturi nozzle. The flue gas enters the absorber through the flue pipe where it is cooled to a temperature of about 80-105°C by water injection. The desulphurising agent calcium hydroxide Ca(OH)₂ is dosed into the absorber. In the absorber, the flue gases react with calcium hydroxide. After the reaction in the fluidised bed, the mixture of flue gas, fly ash and calcium hydroxide leaves the absorber and enters a fabric filter with four modules. Here, the flue gas is cleaned of any residual fly ash. The settled ash and dust residues in the filter media with the addition of reacted Ca(OH)₂ are called the desulphurisation product (unreacted, i.e. active Ca(OH)₂ in the product ranges from 4 - 12%, optimum up to 10%).

To ensure maximum availability, the desulphurisation plant has 2 absorbers. Each absorber is designed for 528,750 Nm³/h of dry flue gas, corresponding to 75% of the rated output, for a maximum inlet SO₂ concentration of [value missing]. For a lower inlet SO₂ concentration of up to 600 mg/Nm³, it is possible to operate one absorber with a flue gas quantity of 620,000 Nm³/h. For the quantity of flue gases to be desulphurised, see the following section.
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This flue gas cleaning procedure is called semi-dry flue gas cleaning - the substances entering the absorber (calcium hydroxide and the return product) should not have a moisture content higher than 1.5%.

Equipment included:
Fluid absorbers 2x 620000Nm3/h
Silo CaO 450 m3
Silo Ca(OH)2 300 m3
Silo desulphurisation product 1000 m3
Scale fan 2x 240 m3/s
Compressor station main 3x 1398 m3/h
Backup compressor station 1x 310 m3/h
Absorption dryers 2x 1916 m3/h
Dieselagregate 80 kW