AQUALYNG

Aqualyng: The low energy consumption solution

Aqualyng: Turning salt water into fresh water

More than one billion people have no access to acceptable drinking water. Less than one percent of the Earth’s water is drinkable in its natural state. The situation has turned critical with increased pollution of rivers and lakes, prolonged drought, non-sustainable use of ground water and the population explosion. One of the UN’s targets for sustainable development is to supply fresh water to 280.000 more people. Per day! This requires better methods for producing drinking water with low energy consumption.

Desalination of seawater is a known method, but has up to now been very energy intensive. Aqualyng has developed a new technology for desalinating water using minimum energy. The technology is fully effective in various sized desalination plants

Aqualyng – The``record`` low energy consumption solution  

Aqualyng AS offers complete, custom-fitted, turn-key desalination plant solutions based upon reverse osmosis. It is according to a total service agreement with plants complete and ready to operate on delivery.

Aqualyng AS offers very flexible alternatives with ready assembled standard modules and a modular building system.

Combining different lines enables construction of a broad range of capacities and we are also flexible to tailor-make and can make plant adaptation to your specific volume and design requirements.

The materials and components used are of the highest quality and are manufactured in industrial environments operating according to the strict specifications set by the oil, offshore and shipping industry. This is due to strong company focus on the aspect of plant adaptation and durability.

Aqualyng AS is dedicated to being environmentally positioned, and we have the tools and the know-how to help you move in the same direction.

Aqualyng AS offers it’s own patented pressure recovery system, called the Recuperator, and plant solutions are based upon a low energy consumption / chemical usage and feature the world’s lowest energy consumption.

Products: Aqualyng Seawater Reverse Osmosis Desalination Plants

The Aqualyng Plant

Aqualyng AS manufactures a range of high quality and compact modules of seawater or brackish water Reverse Osmosis desalination plants of the latest technology with very flexible solutions.

The standard delivery includes:

1. Membrane rack complete in skids
2. Bag filtration
3. Energy recovery system, the Recuperator
4. Feeding tanks
5. High pressure pumps
6. Booster pumps
7. Electrical/control cabinet

Aqualyng can also supply and incorporate other equipment, such as:

• Sand filtration
• Extra bag filtration / finer bag filtration
• Membrane cleaning / flushing system
• Chemical addition systems

All units are preinstalled in skids and can be installed in standardized industrial buildings with the smallest units, up to 1 500 m3/d, installed in containers. The equipment can also be installed on floating badges.

The standard unit sizes offered are:

• 500-700 m3/day  
• 1 000-1 500 m3/day  
• 2 000-2 500 m3/day  
• 4 000-5 000 m3/day  
• n x 5 000 m3/day

Combinations of these standard modular units enable us to construct Reverse Osmosis Systems to almost any size. Aqualyng can also tailor-make plant adaptation and can successfully adapt to your specific volume and design requirements.

Reverse Osmosis Module: 500-700
Very compact solution. It is designed to be installed inside a container. High efficiency and low energy consumption.
Fresh water production capacity: 500-700 m3/day (0.132 - 0.185 Mgal./d)
 
Reverse Osmosis Module: 1000-1500
Very compact and efficient system. Includes all our standard equipments. Optimal surface use. Only 60 m2. High quality fresh water at incredibly low energy consumption rates. Designed to be installed in containers.
Fresh water production capacity: 1000-1500 m3/day (0.264 - 0.37 Mgal./d) 

Reverse Osmosis Module: 2000-2500
Robust and compact conception. Low energy consumption.
Fresh water production capacity: 2000-2500 m3/day (0.53 - 0.66 Mgal./d)  

Reverse Osmosis Module: 4000-5000
Modular design. Starting point for our larger plants. High quality and production capacity from a single module. Only 200 m2 of building required.
Fresh water production capacity: 4000-5000 m3/day (1.06 - 1.32 Mgal./d)

Reverse Osmosis Module: 10000
Solution is based on 2 lines of 5000 m3/d each. An example of our flexibility regarding plant adaptation to customer demands. Aqualyng can deliver complete plants with buildings including office, warehouse, chemical and electrical/control rooms.
Fresh water production capacity: 10 000 m3/day (2.64 Mgal./d)

Technology: The Aqualyng System, Recuperator, Reverse Osmosis

The Aqualyng System

The energy consumption rates for a conventional system (with Pelton turbine as energy recovery device) are around 3 - 4.5 kWh/m3 of fresh water produced from Atlantic seawater. The energy consumption of desalting Atlantic seawater at 200C temperature using the Aqualyng system is 2.0 kWh/m3 of fresh water produced.

Compared to conventional systems with turbines, the Aqualyng system results in a saving of minimum 1.5 kWh/m3. However, the system becomes more advantageous as the feed water salinity increases and savings of 2-3 kWh/m3 is, for example, to be expected for most cases of Red Sea and Persian Gulf applications.

The Aqualyng system uses the brine energy in a special equipment, called the Recuperator, to pressurise seawater to the same pressure as the brine. The process is actually a pump, of the reciprocating principle, hydraulically driven by the brine. The capacity of this ``pump``, in terms of flow and pressure, is the same as the brine stream.

There are no moving parts in the Recuperator, as opposed to other pressure recovery devices, and this increases the durability of the system.

A small booster pump is required to compensate for the pressure drop in the membranes and the piping system. This booster pump increases the pressure of the pre-treated seawater that has gone through the ``pressure recuperator`` up to the operating pressure required at the membranes inlet. As the process delivers seawater at the same flow rate as the brine rejected by the Reverse Osmosis membranes, then the capacity of the high-pressure pump will be equal to the fresh water produced by the membranes.

This means that with a system recovery rate of 40%, 60% of the feed water is delivered by the Recuperator system and only 40% from the high pressure pump.

In conventional Seawater Reverse Osmosis desalination systems; all feed water has to go through the high-pressure pump which only has a modest efficiency, 70-85%, dependent on type and size. The Recuperator has an efficiency of around 98% and this is where the big difference lies.

The Aqualyng Recuperator

The Aqualyng Recuperator consists of two vertical towers and a set of valves. The brine enters through a three-way valve and the flow is diverted to the bottom of one of the towers, which by then is filled with seawater and pre-pressurised. The brine flows into the bottom of the Recuperator and displace the seawater out from the top through the outlet one-way valve and into the booster pump.

At the same time, the other tower is depressurized by a small special heavy-duty depressurizing valve and then the brine is dumped at the bottom through a larger drain valve. While this happens, the same tower is filled up with seawater through another one-way valve at the same rate as the brine is being dumped at the bottom.

When the tower is filled up with seawater and all the brine is drained, then the tower is pressurized again. All this happens before the brine-seawater interface in the other tower has reached the top. Then the three-way valve switches the flow smoothly over to the other side (seawater-full tower).

All the large valves are operated after the pressure is equalized, leading to smooth operation and continuous flow of seawater to the booster pump and the membranes.

With this system we have been able to produce fresh water of very high quality with a minimum of chemicals use and at very low energy consumption rates.

Natural Osmosis and Reverse Osmosis

Natural Osmosis occurs when a membrane separates two solutions with different concentration in water. If the membrane is ideally semi-permeable (permeable to water and not to the solute) then there will be a flow of water from the least concentrated solution to the most concentrated solution.

This flow through the membrane continues up until the two solutions reach equilibrium in their concentrations or the pressure in the most concentrated solution reaches a certain value. This differential pressure between the two solutions is called osmotic pressure. If that value is applied to the solution with higher concentration, the the water will flow in the opposite direction, to the least concentrated solution. That is what is known as Reverse Osmosis (RO). 

Reverse Osmosis is the most complex technique in membrane separation technologies. High pressures of about 35-80 atmospheres (depending mainly on the feed water salinity, temperature and recovery rate) are required in order to overcome the high osmotic pressures across the membrane.

Reverse Osmosis membranes concentrate low molecular weight organic materials and salts while allowing water to pass through them so separating the feed water stream into two flows. The one called product water or permeate with a very good quality, and the other called brine containing high amounts of salts rejected in the membranes and high pressure which is used by Aqualyng’s Recuperator for energy recovery purposes.

Reverse Osmosis has been the most widely used technology for desalting seawater and reclaiming brackish well water in the last 25 years.

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