The Project will be located within the existing site
of the CPPS. A brief description of
the construction and operation of the Project is provided in the following
sections.
2.1
Construction of the Project
2.1.1
Demolition and Relocation of Certain
Existing Facilities
While the existing generating units will remain in their current
locations, some of their auxiliary and common facilities to the south of the
generating units at CPB may be demolished or relocated within CPPS to provide
space for the FGD, SCR and related facilities. The following demolition / relocation
works are envisaged to be required:
·
demolition
of CPB Fuel Oil Day Tank (FODT);
·
demolition
of Dangerous Goods (DG) Store;
·
re-routing
of underground pipeworks;
·
relocation
of CO2 storage tank;
·
relocation
of the LPG storage tanks; and
·
relocation of the Intermediate Pressure Reduction Station
(IPRS).
2.1.2
Installation of the New Emissions Control
Equipment and Facilities
New facilities to be installed for the Project will include the SCR and
FGD equipment, reagent and by-product handling and storage facilities
associated with the SCR and FGD operations. An additional berthing facility for the
loading and unloading of reagents and by-products will also be required. These are described in the following
sections.
Installation of SCR and FGD Facilities
The SCR and FGD facilities will be retrofitted to the CPB generating
units. The exact footprint of these
facilities will be finalized upon design optimisation.
Provision of Reagent and By-product Handling and
Storage Facilities
The major reagent and by-product handling facilities for FGD operations
will include limestone storage facilities, limestone slurry tanks, gypsum
dewatering and storage facilities, and handling and storage facilities for
lower grade gypsum. SCR systems
will require urea as the ammonia supply reagent, urea
storage facilities, dissolvers, urea solution storage tanks and urea-to-ammonia
reactors will be required.
Provision of Additional Berthing Facility
The SCR systems could require about 40,000 tonnes per annum (tpa) of urea, while the FGD
systems could consume about 150,000 tpa of limestone
and generate about 257,000 tpa of gypsum as
by-product. The quantities of
reagents required and by-product produced will be finalised during the design
engineering phase. An additional
berthing facility will be needed for the loading and unloading of process
reagents and by-product.
The provision of additional berthing is by extending the existing Heavy
Load Berth to form a multi-purpose wharf, providing a straight quay with the
potential to accommodate ships with a wide range of loaded draft
requirements. It is anticipated
that the extension work will require some small-scale dredging
for the foundations of the deck and for providing a sufficient turning basin
for the different marine vessels’ loaded draft requirements.
The
preliminary general arrangements of the proposed facilities are shown in Figures
2.1.
2.2
Operation of the Project
The operations involved in the control of emissions from CPB are
summarised in the following sections:
2.2.1
Selective
Catalytic Reduction Process
In the selective catalytic reduction (SCR) process, a nitrogen-based chemical
reagent in the form of ammonia (NH3) is injected into the flue gas upstream
of the SCR catalyst. The ammonia
will be generated from a urea-to-ammonia conversion system and will selectively
react with nitrogen oxides (NOx) in the presence of a catalyst
to form nitrogen (N2) and water vapour (H2O).
The reactions are essentially the conversion of various nitrogen oxides
in the flue gas to nitrogen gas (N2).
The oxygen removed from the nitrogen oxides combines with hydrogen to
form water (H2O). The
products of the reactions, nitrogen gas (N2) and water (H2O), are innocuous and exist naturally in
the atmosphere in large quantities.
2.2.2
Limestone Flue Gas
Desulphurisation (LS FGD) Process
In a LS FGD system, the flue gas enters a
large vessel (usually known as the ‘absorber’), where it is sprayed with or
bubbles through limestone slurry in the absorber. The calcium carbonate (CaCO3) from limestone in the slurry reacts with
the sulphur dioxide (SO2) in the flue gas to form calcium sulphite (CaSO3).
The calcium sulphite initially formed in the absorber is nearly 100%
oxidised to form gypsum (CaSO4, calcium sulphate) by the provision of oxidation air into the sulphite
slurry in a separate vessel, or in-situ,
depending on the technology design.
The gypsum generated can be commercially recycled.
The schematics of the emissions control systems are presented in Figure 2.2.
2.3
Proposed Project
Programme
Subject to timely agreement of a long-term environmental policy with the
HKSAR Government and the successor regulatory regime, the currently envisaged
project milestones are as follows:
|
Key Stage of the
Project |
Indicative Date |
|
Finalisation of other major permitting requirements |
2006 |
|
Completion of front-end engineering design |
1st half of 2007 |
|
Commencement of relocation of existing facilities |
1st half of 2007 |
|
Award of major contracts |
2007 |
|
Commencement of retrofit site work |
End 2007 |
|
Start-up of the retrofitted units |
End 2009 to 2011 |