Water Journal : Water Journal May 2012
refereed paper water in mining water MAY 2012 71 Abstract Origin Energy and Shell (formerly Arrow Energy) are major players in the coal seam methane market in Queensland. Australia's carbon tax and emissions trading scheme (ETS) will make coal-fired electricity increasingly more expensive. The intention of an Energy Trading Scheme is to motivate major CO2 producers to switch from coal to natural gas and/or renewables. Aquatec- Maxcon has provided a number of micro- turbines ranging from 30kW to 1MW for gas well heads in the coal seam gas (CSG) market, which provide power directly at the source of the gas. Through this relationship Aquatec-Maxcon was requested to provide a number of containerised integrated micro-filtration (MF) and reverse osmosis (RO) plants that can be dismantled, connected to a new storage dam and recommissioned if required at different well locations. The design of the RO plant is challenging, as it needs to deal with a wide range in raw water conductivity, as water can vary vastly over the region and is mainly drawn from the Artesian basin. The integrated membrane plant includes screening, microfiltration (MF), reverse osmosis (RO), as well as acidication and antiscalant dosing. Both the MF and RO systems are designed with a conservative flux in order to treat a high bacterial and organic load from open dams. The RO system has been designed to operate as either two or three stages depending on the feed water conductivity at the particular extraction area in the gas field. We have completed two plants for Shell at Dalby and Moranbah. The plant at Dalby has two stages and operates at 75 per cent. The plant at Moranbah and at Talinga for Origin Energy is a three-stage RO system capable of operation up to 85 per cent. Aquatec-Maxcon has a fabrication workshop in Ipswich, and it was a requirement of the client to house all the technology and equipment, including air compressors, pumps and clean-in-place systems, inside 40ft (12m) containers. The client also requested that the plants include interconnecting pipework with quick-release fittings, electrical type plug and sockets, and removable pipework and cable trays. This was to ensure the plant could be transported easily to another site where water demand is required for industrial, agricultural or domestic use. Introduction Aquatec-Maxcon has been involved in the coal seam gas (CSG) market for over four years. When the Energy Trading scheme started to take shape, the company got involved in clean energy and became the distributor for capstone micro-turbines in Australia. Typically, CSG companies compress gas and transfer it down pipelines to a centralised power station. However, there was no electrical grid network around Talinga. Origin Energy wanted to construct a 20 ML/d membrane treatment facility in Talinga. Origin Energy purchased gas turbines from Aquatec-Maxcon on their gas wells to provide standalone power up to 3MW for their site facilities and reverse osmosis plant at Talinga. To date, we have provided over 150 of these gas engine turbines to Origin Energy. Using CSG to generate electricity instead of coal, we can reduce greenhouse emissions by up to 70 per cent. These gas engines have one moving part and operate on air bearings. The turbines don't suffer issues with corrosion due to sulphides in methane gas. These units are standalone co-generation facilities providing low-grade waste heat and electrical power. It was at that time that we were asked as a water company to provide integrated membrane systems to accompany these power generation units. Aquatec Services and its electrical company MPA provide backup service and support to Origin and Arrow Energy from Chinchilla as required. General Background The Australian coal seam gas (CSG) industry has grown significantly in recent years and several multi-billion dollar developments have occurred in the CSG fields of central and eastern Queensland (see Figure 2). Arrow Energy is a $2.3 billion vertically integrated specialist CSG company, with a huge domestic acreage position over eastern Australian coal beds with 1,430 PJ of reserves and 5,084 PJ of additional gross reserves. Arrow Energy has a wide alliance with Royal Dutch Shell and Petrochina. Origin Energy is a $7 billion integrated A Davey, R Howick, R Armbruster TREATMENT OF COAL SEAM METHANE WATER IN TALINGA, DALBY AND MORANBAH Figure 1. A 3MW gas co-generation facility for the Talinga treatment plant.
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