GRP PIPES AND FITTINGS CURAÇAO SEAWATER DESALINATION PLANT DEGREMONT

Transcription

1 The most complete solutions in GRP PIPES AND FITTINGS CURAÇAO DEGREMONT (Netherland Antilles) 2008 / D-2 C A S E S T O R Y SWDP

2 desalination PROTESA MANUFACTURES, SUPPLIES AND INSTALLS THE PROCESS PIPING IN G.R.P. FOR THE CURAÇAO SWDP Job: Low pressure pipe erection in the Seawater Desalination Plant Client: Degremont. Site: Santa Barbara Area - Curaçao (Netherland Antilles). Capacity: m 3/day. Technology: Reverse Osmosis. Treated water quality: TDS = 300 ppm. Steps: 1.- Seawater discharge pipe. 2.- Chemical pretreatment. 3.- Filtration through sand filters. 4.- Filtration through cartridge filters. 5.- Suction pipe to the high pressure pump. 6.- Reverse osmosis - collecting pipe of permeate of the first step and second step and second step feeding pipe. 7.- Product water pipe. 8.- Brine pipe (after turbine discharge). 9.- Auxiliary systems: a) Sand filter washing system. b) Membrane chemical washing system. c) Displacement pipe. d) Osmotic equilibrium tank. Fig.1.- Illustrative diagram of plant equipment

3 CURAÇAO C A S E S T O R Y SWDP PROTESA's scope begins with the fabrication and supply of the entire pipe mentioned above, as well as all the parts and fittings which are proper of the installation of a desalination plant (flanges, reducers, elbows, etc.). In the same manner, an erection team has been provided for the pipe installation. All of it means the execution of chemical welds, inserts, etc. all of them executed in the field, apart from other necessary actions for the correct installation of the pipe. Technical counseling has been carried out, at all times, through the Engineering and Erection Departments of PROTESA in order to establish a dynamic communication in the resolution of the possible problems derived from execution of the works. CHEMICAL PRETREATMENT. For the elimination of bacteria and disinfection of water, a chemical pretreatment is performed by means of the application of sodium hypochlorite. Afterwards, an acidifying agent is applied by means of the application of sulfuric acid in order to prevent the precipitation of calcium carbonate in the membranes upon the concentration of seawater. The application of these chemical products is performed in the seawater discharge line itself. Fig. 2.- View of the discharge header with the chemical reagents dosing equipment. The storage of such products is performed in the purple color tanks.

4 desalination Besides, due to the environmental characteristics of the zone (tropical climate), the water presents a high biological culture which is eliminated by means of an active carbon filtration step. In this manner, we eliminate the bacteria present in the water and we make it colorless and odorless. The water supply to the filters as well as their outlets and the entire circulation pipe of the same is performed with PROTESA pipe. Fig Start of the filter piping arrangement installation Fig. 4.-Front view during the erection stages (inlet of water to be filtered).

5 CURAÇAO C A S E S T O R Y SWDP Fig. 5. Complete erection of active carbon filter, with the incorporation of valves and equipment of metering and automation. SIDE VIEW. Fig Complete erection of active carbon filters pipe with the incorporation of valves and equipment of metering and automation. FRONT VIEW. FILTRATION BY MEANS OF SAND FILTERS The following step is the filtering of the sand or other particles in suspension of intermediate size, which undoubtedly would damage the osmosis membranes. The water is filtered by means of the so called "sand filters". The body of these is located in the outside wall of the building, while its piping front is in the inside. All of the canalization has been designed with GRP piping supplied and installed by PROTESA. Fig. 7.- View of the connection collectors between filters Fig. 8.- View of the collectors of connection between filters, practically having completed their erection.

6 desalination Fig. 9.- Side view of the inlet of piping coming from the filters to the inside of the plant. Fig.10.- Front view of filters from inside the plant, with practically all of the metering valves and elements installed

7 CURAÇAO C A S E S T O R Y SWDP FILTRATION BY MEANS OF CARTRIDGE FILTERS Once the intermediate size particles are eliminated, another filtration step is carried out by means of some cartridge filters for the full elimination of the small particles in suspension Before the inlet to the cartridges, the water undergoes a second treatment with the application of sodium bisulfate, in order to eliminate the residual chlorine which could oxidize in the membranes. An anti-scale agent is likewise dosed with the purpose of preventing the precipitation of calcium sulfates salts upon concentration of the seawater in the membranes. Likewise, if the circumstances so require it, an elimination of the matters in suspension is carried out by means of the addition of a coagulant, normally ferric chloride. Fig Top view of water inlet to the cartridge filters (in blue). Fig.12.- Bottom view of the cartridge filter headers (filtered water outlet).

8 desalination HIGH PRESSURE PUMP SUCTION PIPE As previously shown, the filtered water passes to the high pressure pumping system through some of the cartridge filters projecting collectors. From there it will be impelled at a pressure which can be of around 70 bar, in order to be able to overcome the osmotic pressure and make possible the process of reverse osmosis. The water circulation up to the pumps is performed by means of PROTESA GRP pipe. The high pressure pipe is of stainless steel. Fig Overhead view high pressure pumping equipment. In the upper part of the pump, the brine conduction is observed which, again recirculates the rejection water to a turbine solidary with the main pump shaft for better performance and energetic reuse. Fig Connection to pump of the water supply from the cartridge filters, to the high pressure pump.

9 CURAÇAO C A S E S T O R Y SWDP REVERSE OSMOSIS. LOW PRESSURE PIPE/SECOND PASS CIRCULATION. Below we indicate the pipe corresponding the skids, the pipe between the two passes of membranes and the product water collecting pipe after the osmosis process. Grupo Fig15.- Different views of the GRP pipes in the REVERSE OSMOSIS skids during the installation process.

10 desalación AUXILIARY EQUIPMENT: Membrane cleaning system. In order to lengthen the efficient life of the membranes, they must be cleaned periodically. For this reason, a product of chemical cleaning is recirculated through the membranes of a skid, after having stopped the same. The system of chemical cleaning consists of a cleaning tank, the recirculation pumps, one cartridge filter in order to filter the cleaning solution before entering into the membranes, the pipe of discharge to the membrane skid and the return pipe to the chemical cleaning tank. The water used for the preparation of chemical cleaning solution is impelled to the cleaning tank from an outside storage tank. The greater part of the washing water, will leave due to the rejection of the modules, together with the dissolved precipitates and small particles coming from the membrane fouling. This outlet water will again be taken to the cleaning tank, establishing a recirculation of the chemical product. Group Figs.16.- View of the pumping equipment for cleaning water impelling, from the washing tank to the membrane skids and of the circulation pipe of cleaning water in direction to the skids.

11 CURAÇAO SWDP C A S E S T O R Y Displacing Equipment. The purpose is to displace the salty water of the circuit (skids and turbine pumps) during the long periods of plant shutdown in order to avoid precipitations in the membranes. For this reason, treated water is recirculated from a tank located in the outside of the plant in order fill the pipe. This same tank could adopt the function of supplying the service water. The conduction of such canalization has also been executed in GRP, pipe fabricated in Protesa and installed on site by our field erection team. Sand filter washing. For washing of the sand filters, available is a pump room common to other applications, from where the blowing water is impelled and with the configuration of the suitable line, the direction of the rejection water of high sand concentration up to its discharge is obtained. Fig.17.- Pumping room. Washing Water of sand filters. Water of active carbon filter washing and reverse osmosis membrane washing Water. Osmotic equilibrium tank. In order to prevent that the membranes remain with water of high salt concentration, especially during the shutdowns due to electric supply cut-off, an osmotic equilibrium tank is placed above the membrane skids (Fig. 18) Fig.18

12 CURAÇAO-DEGREMONT Xavier Arasanz Corominas Sales Manager P R O T E C C I O N E S P L Á S T I C A S, S. A. c/industria, 3-5 Pol. Industrial Anoia SANT ESTEVE SESROVIRES Barcelona - España Tel. (+34) Fax (+34) protesa@protesa.es Producto certificado por BUREAU VERITAS Certification