The Anglesea Power Station (APS) project involves retrofitting and integrating a flue gas desulphurization process with the power station. The power station comprises a 160-MW boiler and utilizes brown coal mined from a dedicated mine at the site. The brown coal has a high sulphur content averaging 3.5%, which produces relatively high sulphur dioxide (SO2) emissions via the existing chimney. The purpose of the project is to reduce stack SO2 emissions and thus ground level concentrations in surroundings areas. Building on an earlier Hatch study, the technology selected is Wet Limestone Slurry/Forced Oxidation (WLSFO).
The project comprises a proven engineering solution for reducing sulphur-based emissions by treating 100% of the exhaust flue gases in a scrubber at 93% SO2 removal efficiency. The sulphur in the gas is treated with limestone to chemically remove the sulphur dioxide with the resulting by-product converted to a stabilized gypsum byproduct. The limestone reagent is sourced locally and gypsum potentially used in both industrial and agricultural markets.
The project scope includes the following components:
- WLSFO FGD process design; energy, mass and materials balances; process support for limestone reactivity assessment
- Limestone receiving, handling, grinding and storage facilities
- Gas path ductwork modifications, new dampers and flue gas booster fans
- Absorber island complete with recirculation pumping system and forced oxidation system
- Primary and secondary gypsum dewatering, handling and storage facilities
- New chimney designed for wet flue gas
- HV/LV power and control system
- Plant-wide infrastructure and utilities
- Modifications to the existing plant facilities to integrate the new FGD system and related works.
Hatch conducted a feasibility study to retrofit and integrate a wet flue gas desulphurization system into a brown-coal-fired power station to reduce ground level concentrations of sulphur dioxide. The power station is owned by Alcoa World Alumina and supplies 45% of local smelter power needs.
The study included site studies, design engineering, estimating and implementation planning, consulting with environmental agencies and affected stakeholders, and services for securing all needed environmental approvals and permits for the project.
An integrated team was established comprising client site personnel, local Hatch project management and engineers with specialist support from other Hatch offices in Canada, Newcastle and Wollongong.
The feasibility study was completed on schedule and met all the customer key criteria associated with capital cost, operating expenses, energy efficiency, reliability/maintainability and utilization of raw materials and utilities.
Value-added outcomes of the project included:
- Strategic contracting strategy that achieved overall CAPEX savings
- Customised limestone receiving facility and vertical mill preparation equipment to match the local soft limestone
- Limestone reactivity review and reactivity testing support
- Identified opportunity for flue gas heat recovery to mitigate CO2 emissions and water requirements
- Gas path bypass system to improve reliability and flexibility of power station
- Utilization of centrifuges for dewatering of gypsum to meet current and potential product quality requirements
- Integration of process equipment, structures, utilities and footprint to minimize overall costs
