Pure water for MHI in Turkmenistan TGF plant
21 Dec 2018
The Turkmenistan Garabogaz Fertiliser, also known as TGF, will be the largest fertiliser plant in Turkmenistan.
TGF is a complex based upon a huge ammonia plant with production capacity of 2,000 tons per day and 3,500 tons per day of Urea. It will be the pioneer of many other similar projects in the near future. The TGF project has been developed by Mitsubishi Heavy Industries with Cannon Artes as its partner for the water treatment facilities.
Mitsubishi Heavy Industries (MHI) with 83,000 employees is an industrial giant involved in very diversified sectors including, Chemicals & Fertilisers, Power Generation, Infrastructure, Aircraft, Defense & Space.
MHI, together with the Consortium consisting of Mitsubishi Corporation and GAP Insaat Yatirim ve DIS Ticaret A.S. companies, has been contracted by Turkmenhimiya, a public Turkmenistan company, for the engineering, procurement and construction and start up of this massive fertilizer plant located in Garabogaz, north-west part of the country, on the Caspian sea.
The country underwent an economic boom in the most recent years and for this reason the Turkmen government is implementing a plan seeking to enhance the value of natural gas, of which Turkmenistan is rich, by converting it into Nitrogen-based fertilisers products.
The installation of a fertilizer plant is accordant with the strategy of giving extra value to the area. The plant will employ at least 700 people when in operation and will allow a relevant increase of the export of fertiliser s in response to the growing request of agricultural food.
For such a huge complex, Mitsubishi involved Cannon Artes, a Company part of the Cannon Group, for the design and construction of all the involved water treatment facilities.
The water treatment plant, as part of the TFG project, is fully designed and realized by Cannon Artes’ expert engineers and technicians, and installed in a 10,000 sqm building (170 meters long and 60 meters wide, 1.5 times a football field).
Cannon Artes supply consists of different stages: pretreatment, desalination, demineralization, condensate polishing and waste water treatment: from high-salinity sea water to ultra-pure demineralized water suitable to feed high-pressure boilers.
The desalination system will be fed with Caspian Sea water to produce demineralized water through several steps.
The capacity of the plant is 300 m3/h when seawater is used as feedstock and of 230 m3/h using the return steam condensate from the process.
The desalination plant is definitely crucial for the TGF complex: as abundant fresh water is not locally available, the water necessary for the process and utilities is taken only from the Caspian Sea and treated to produce demineralized water through several steps. Desalination is achieved with Reverse Osmosis (RO) technology where water is pumped across semipermeable membranes, permeable just to salt-free water, while a concentrate stream collecting all salts is then returned to the sea.
Furthermore, the design of the system had to take into account also that seawater is a “live” environment, rich with algae and microorganisms, and a key point in seawater desalination is the pre-treatment designed to prevent the fouling of the Reverse Osmosis membranes.
In the pretreatment section, seawater, after mixing with coagulant and hypochlorite, is sent to Dual Media Filters arranged on a double pass with different filtration rates.
Filtered water is then mixed with antiscalant and dechlorination agent and is fed to cartridge filters prior to RO system.
Due to its high salinity seawater, It has to be pumped at high pressure in order to win the osmotic pressure and to achieve in this way an acceptable recovery of the water itself. Medium-voltage electrical motors and variable frequency drivers (VFDs) are implemented to manage the high pressure (ab. 70 bar), the large capacity and the necessity to optimize the operational efficiency with the actual required flow.
On the other side the desalinated water coming from Reverse Osmosis section proceeds to the demineralization system for removal of residual ions. Such system is arranged on two trains, one cationic and one anionic vessel.
Polishing is the last step for the water treatment system: before feeding the boilers, the demineralized water coming from demineralization section is mixed with the recovered steam condensate coming from the process and undergoes a further treatment with Mixed Bed Exchangers to remove traces of ions and reach an electrical conductivity close to that of pure water. Also dissolved silica is reduced down to parts per billion. Cannon Artes’ scope of supply also includes the complete regeneration system of the ion exchangers which consist of Sulphuric acid and caustic soda handling facilities (tanks, dosing pumps, regeneration pumps and dilution system).
Another key factor that was duly taken into account in the design stage was the accurate selection of materials owing to the fact that seawater is responsible for a highly corrosive environment due, in particular, to the Chloride content.
Cannon Artes’ supply for TGF also included the waste water treatment plant for the whole complex, composed by a de-oiling system based on Corrugated Plates Interceptor to remove oil and suspended solids from the contaminated rain water and a neutralization system capable to adjust the pH before discharge.
The strong point contributing to the success and the satisfaction of the customer has been the care and attention that Cannon Artes has dedicated to the project from the very beginning to the end: the process and detailed engineering were entirely developed in its own offices in Milan and Salerno, the plant was manufactured, pre-assembled and tested in their own 40,000 sqm factory of Oliveto Citra, near Salerno. Cannon Artes personnel has also carefully supervised erection, pre-commissioning, commissioning and start-up on site.
The plant is a flagship for Cannon Artes because, for such a significant project , it was able to use its own “know how” and every competence in all expertise areas.
Artes is proud to have put together all these water treatment technologies water in a single and integrated system. Moreover, the capability to adapt the plant during construction when new environmental requirements emerged, is reason for pride.
TGF will be able to provide further news and details once the overall plant is totally completed.