On the same day (Feb 11, 2008) when South Bound Lyari Expressway was inaugurated, another important project of Pakistan reached its opening milestone. This one is called the DHA Desalination and Power Plant. It is the first project of its kind in Pakistan which desalinates water from the Arabian Sea for human consumption as well as provides Electrical Power to the KESC Grid.
The Capacity:
The capacity of the Power plant is 94 MW (Mega Watts) and that of the desalination plant is 3 MIGD (Million Imperial Gallons per Day). Electrical Power generated here is supplied to the 132 KV (kilo-volt) KESC grid whereas the Desalinated Water is supplied to CBC/DHA for local distribution.
The fuel for the Power Plant is Natural Gas which will be provided by the Sui Southern Gas Company Limited (SSGCL) via 20″ diameter pipeline. The Electrical Power is generated by two turbines. One is Gas fired with the generation capacity of 67MW. The other is Steam fired with the generation capacity of 27 MW.
Who Did What:
The project is carried out by DHA Cogen Limited (DCL). It is a Public Limited Company which was incorporated in the city of Karachi on January 19, 2003. The company is a joint venture between Defence Housing Authority, Karachi (DHA) and Sacoden Investments, Singapore (SI). The contract for building the Power Plant was given to Siemens AG Germany (SAG) who also supplied the two turbines used in the plant. The Desalination Plant is built by Alfa Level, Copenhagen, Denmark (ALC) and the civil works is carried out by Siemens Pakistan (SPK).
Following is the photo of DHA Desalination Plant
The Civil Works component of the project was a huge task in itself which included the necessary support infrastructure in terms of fuel gas supply, seawater intake, 132KV Sub Station, water treatment, under ground storage, workshop, stores, control room and administration offices.
The Processes:
A neat thing about this project is that a by-product of power generation i.e. steam is used as a fuel to desalinate water. The two power turbines of the Power station are connected together (as a single shaft configuration) along with a Heat Recovery Steam Generator (HRSG). The steam turbine is designed to exhaust steam directly to the two MED (multi effect distillation) plants to provide energy input to the MED desalination process.
The photo to the above right shows MED desalination plant installed at HUBCO Karachi. It is similar in MED processes but much smaller in design to the DHA Desalination plant.
Another Success Story of Pakistani Engineers
Here I also want to mention yet another success story coming out of Pakistan’s Public universities. The local project Manager of Siemens AG Germany overseeing the work on the Power Plant is Mr. Yasir Jilani, a EE graduate from the NED University of Engineering and Technology, Karachi. I want to present it yet another success story of Engineering graduates coming out of Pakistan’s public Educational System.
Location of the Plant
Plant is located at the southern tip of DHA phase VIII. Google Earth has not been updated for Karachi for many years now therefore it still shows a flat ground in most of DHA phase VIII. The pointer in following image shows where the present day plant is located
In an age when Pakistan is facing serious power shortage, this plant is certainly a welcome addition.
Pakistan’s Other Water Desalination Plants:
1. A desalination plant was installed in 1987 in Saindak Copper Mines in Balochistan. This plant uses the brackish water Reverse Osmosis (BWRO) process.
2. Another desalination plant was installed in 1995 and commissioned in 1996 at the HUBCO power station outside Karachi. This plant uses Reheat type Multi-effect distillation (MED) desalination.
3. KANUPP near Karachi operates a Sea Water Reverse Osmosis (SWRO) desalination plant to meet its operating requirements.
References:
1. DHA Cogen Limited
2. Dawn Newspaper Report on Plant Inauguration
3. Google Earth
Owais
“Desalinated Water is supplied to CBC/DHA for local distribution.”
Desalinated water is not potable so it cannot be supplied via normal water supply channels. I am living in Saudi Arabia where almost all of the water used for domestic purposes is desalinated. However, we have to buy drinking and cooking water separately. In Pakistan normal households use tap water for drinking after some filtering / boiling. I do not know how they will divide normal water and desalinated water in the distribution system.
Other big concern of desalination is brine (residue salt from filteration process). The brine is pumped back into the sea effecting the ecosystem.
Anyhow, in this extreme scarcity of water and electricity, this plant may give some relief to Karachi.
Good work and congrats to Yasir, afterall he is our classmate so we can also take some pride:))
My friend’s company has been sub-contracted for a few important factors of the project.
In the midst of all the applause and appreciations, I have some bad news to report.
Interestingly, our diligent DHA planners and the Siemens consultant have failed to take the winter Sea level in account, and the power generation aspect of the project will seriously suffer during its winter operations.
The whole project feasibility has been drawn based on its 12 month average performance, and the power generation is one of the biggest income sources. At its trail run during November and December 2007, the plant management was seriously disturbed to find out the tides staying atleast 2 Km away from the turbines on most of the lower lunar cycles.
A suggestion has been floated to lay a pipe from the low tide level drawing the water to the plant, to atleast run the desalination plant during winters, however the costs and the power requirement for the whole process may even make it unfeasible aswell.
I am seriously hoping to be proved wrong on this, however.
How long would Sui Gas last? This isn’t the only oil / gas fired power plant being set up. Numerous others are popping up all over the country. Saif, AttockGen, Nishat and Nishat Chunian to name a few. But they’ll put more burden on either depleting gas or rising oil import bill. Look at what existing IPPs are doing on the following business recorder link:
Government to issue show-cause notices to IPPs: failure to maintain plants efficiency, fuel stocks
We desperately need alternative energy options.
The desalination plant is a good thing, being fueled by steam. That’s even better.
any idea to what extent this plant will remove water shortage in defence ?
this is a laudable effort and perhaps long overdue