Desalination is a process that removes soluble salts from water to render it suitable for drinking, irrigation or industrial uses.
With limited sources of fresh water available to growing populations, finding new sources of potable water is an increasingly important issue. Improved methods of water treatment are making desalination plants a more attractive method for solving this problem.
Today there are two main desalination technologies, based on membranes and thermal processes.
Membranes desalination uses the principle of osmosis to remove salt and other impurities, by transferring water through a series of semi-permeable membranes. Membranes desalination includes Reverse Osmosis, Nanofiltration, Electrodeionization, Electrodialysis reversal.
Thermal desalination uses heat, often waste heat from power plants or refineries, to evaporate and condense water to purify it. Such technologies include multiple-effect distillation (MED), multi-stage flash evaporation (MSF), Vapor compression.
Some of the technologies to be applied to this type of process are listed to follow:
Off Shore
The off shore systems require not only the deep knowledge of the process, but also the capability to take into account very severe environmental condition, lack of space, the respect of very strict standard requirements (as an example NORSOK specification).
Gemwater has an extensive experience in off- shore water treatment, as demonstrated by its reference list and staff experience list.
Some of the processes to be applied in this market are listed to follow:
SODIUM HYPOCHLORITE PRODUCTION THROUGH ELECTROLYSIS
Gemwater is proud to present the range of products for the Sodium Hypochlorite Production. Thanks to the integration of qualified personnel to the existing structure and the creation of strategic alliances, Gemwater is able to realize any size of plant, following any type of Standard requirement from Customer and End Users.
Electrochlorination is the preferred system to control biofouling in piping and in system which use big quantities of seawater for cooling. Electrochlorination plants are present in several industrial fields such as in Power plants, Refineries, Desalination plants and others.
The core of the plant is the electrolysis section which provides the hypochlorite solution, through electrolysis of seawater or brine. The type of electrodes devices depends on the different application foreseen.
We may identify two main categories which are described in detail in the dedicated sections, depending on the raw feed fluid interested (seawater or artificial brine).
In hypochlorite production from seawater, electrode cells can be ‘plate type’ electrodes. The cells are of different sizes, modular, and combined they can provide any range of production required.
In offshore installations the preferred electrode cells are named Concentric Tubular Electrodes (CTE), characterized by easy handling and maintenance, no requirement of acid cleaning, very compact layout.
Sodium Hypochlorite production from brine is used in the disinfection for potabilization, in agriculture, in chemical industries, in housekeeping market, in fertilizers, pharmaceutical and in many other fields. In this case, electrode cells can be membrane or diaphragm type electrodes.
Some of the technologies to be applied to this type of process are listed to follow:
Extraction of oil from reservoir wells is always accompanied by a production of water, called “Produced Water”, which is usually a mix of formation and connate water (which are the water naturally present in the reservoir), as well injection water which can be previously injected in the oil wells.
Produced water is usually a salty water normally containing:
• Dissolved Gases (Hydrocarbon, Carbon Dioxide, Hydrogen Sulfide, Ammonia)
• Oil & grease
• Suspended solids
Over time, as the reservoir tend to depletion, the quantity of produced water increases. Therefore, treatment of the water to comply with specification for injection as well as with legislation for disposal, is recognized a key aspects of the oil business.
Many key aspects shall be evaluated in the selection of the proper treatment technology, like:
• Water flow rate and variability in flow oil concentration solids etc.
• Water quality in (from wells, separators): oil droplet & solids particle concentration and size distribution,
production chemicals
• Water quality out (specification for discharge PWRI)
• Weight and footprint, operability, redundancy, expandility, etc.
There are a wide range of physical processes for produced water treatment. Main tasks of the produced water treatment processes for water injection and disposal are the removal of oil and suspended solids. In case of treatment for water reuse (industrial and agricultural), the task is the removal of salts, organics, silica and colloidal by means of Thermal Evaporation.
Some of the technologies to be applied to this type of process are listed to follow:
