Page 44 - Industrial Plant 2020

technical plan to reduce air pollutants and
noise emissions to extremely low levels – this is now Boldrocchi APC solutions
have been tailored
the lowest emitting biomass power plant in Italy.
Boldrocchi was commissioned by for plants firing
the Customer to achieve extremely
low levels of air pollutants and • Waste or virgin wood chips
Biomass pellets (and other dry biomass)
•
noise - this is now the biomass • Straw
power plant in Italy with the lowest • Bagasse
emissions • Green waste

Reducing air pollution for process control at the catalyst reactor.
Boldrocchi experts in FGT designed and manufactured When a tail-end solution is chosen, particular attention
a tailored-made multi-pollutant removal solution for the must be paid to the operating temperature to avoid
plant’s operation, in compliance with air pollutant catalyst poisoning and/or obstruction, due to
reduction targets but keeping a close watch on the ammonium sulfate formation on the catalyst surface,
budget. that would reduce its performance. For this reason, the
To attain those results, the flue gas line was engineered specialized Boldrocchi team decided to install a main
as following: gas burner for flue gas temperature control and
• Cyclones to act as particulate pre-separators; catalyst thermal regeneration.
• A Dry Reactor that nearly eliminates acid gases Finally, also the De NOx reactor sizing was conceived
using bicarbonate of micronized sodium to grant a maximum operational flexibility: the casing
injections; holds 2 active layers and a spare layer in order to allow
• A pulse-jet fabric filter (baghouse) that completes greater flexibility on operational parameters and
the acid abatement reaction; minimize the downtime if maintenance is required.
• A DeNOx SCR (Selective Catalytic Reduction) Boldrocchi achieved these objectives with specific
system for dropping NOX using aqueous urea. choices and technological details based on experience
acquired in the sector.
The choice to install a dry reactor for SOx/HCl removal In particular, regarding chemical compound emissions,
was included considering the need for a compact and during the Performance Tests we registered extremely
flexible design approach that would include a fraction low emissions and – in some cases – (almost) zero
of the capital, operational and maintenance costs vs. emissions (Table 1).
the installation of a wet system. Furthermore, the
resulting by-product could have been used as filler or
landfilled – without additional costs for treatment. Reducing noise pollution
A similar CAPEX/OPEX analysis resulted into the Boldrocchi was also contracted to reduce noise. The
decision of a DE NOx SCR system. specific objective was to reduce the sound pressure to
A complete De NOx system was supplied using urea scale A and to under 60 dB (A) from the perimeter
as a reagent (which is transformed into ammonia once fence 7 meters from a pipe linked to the smoke line
evaporated). The system includes the urea preparation, where the original noise level was 67 dB (A).
gasification, injection, and a dedicated NOx analyzer Boldrocchi’s noise specialists did a precise and

DEDUSTING TREATMENT FILTERING TREATMENT EXTRACTION

HEAT
CYCLONES REACTOR BAG FILTER DeNOx STACK FAN
EXCHANGER

Flue Gas Temperature Sodium Bicarbonate Filter Pre-heating System Urea Storage and Dosing Silencer and Exhaust Stack
Control Storage and Dosing

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IndustrIal Plants - May 2020
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