Fresh Water Distillate Pump

Fresh piss supply Distillate PumpINTRODUCTION .There was MOD vas on the port and this vessel required a sweet-smelling piss for the 50 crew on the direct. So i have to make a system to produce fresh weewee on that ship. But the problem is that the ship is at port and there is lot of licentiousness present in the port ocean piddle system such as thoroughgoing waste which contain briny(prenominal)ly garbage ,untreated sewage which tin discharge directly or indirectly in the ocean.treaces of big(p) metals also present mercury,cadmium,,chromium these heavy metals are dangerous to health and also to the environment.heavy metals such as zinc and lead may sticks corrosion .beside of these there was sone anthropogenetic source of waste present which are listed be beginning.Mining effluentsDomestic effluentsIndustrial effluentsShipping activities including those of motorised boats and burn downoes.Fertilizers pesticidesAtmospheric sources such as gas flaring, incineration of d omestic waste manly garbage.Petroleum industries activities.According to uk wet regulation the perctange of some heavy metals essential be at certain levelCALCULATIONBefore choosing any(prenominal) generator I have to calculate the irrigate system which fulfil the requirement of 50 persons.In a ship one person can MAXIUM 600 to 800 litres per twenty-four hour period. A person can use the fresh piss for washing clothes, washing utensils, wash room, inebriation, cooking, bathing, and etc.If we calculate the fresh water for the 50 persons is800*50= 40000 litres per dayso i have to chose a system which is capable for the work of minim 40000 liter per dayTYPES OF FREH WATER GENERATORin an efficient locomotive, but about half of the agitate in the fuel is converted into useful work some of the Heat energy is lost in the cool down systems and secrete gas. but some of the heat lost is recovered . the Modern highly pressure charged engines have a enormous amount of energy in s cavenge air cooling wateer and this can be provide as the source of heat up to the bunkering .an different source of heat is jacket water cooling and it also contain considerable amount of heat and this heat can be recovered in the fresh water evaporator system which ope prescribe at the pressure giving a corresponding saturation temperature fo water downcaster the the jacket water entering in to the heating strong buck .gasses dissolve when water is heated to its saturation temperature.There are cardinal methods for generating fresh water,1.Reverse Osmosis2. distillate.is generally use were large quantities of relatively low tint water is required. typical examples of water produced areTreatmentTotal HardnessCalcium HardnessSilicaSodium ChlorideTDSSea Water250200141500015000EvaporatorReverse Osmosis205After Demineraliser0Trace.DistillationThe most comm yet use freshwater generation is evaporative distillation, which uses engine jacket cooling water or steam heat from exhaus t or gas fired boilers to evapo place sea water, which is consequently condensed into fresh water. Evaporation distillers comes in deuce main forms, 1.multistage flash2 multi effect evaporators.Simple single effect evaporatorThe system above shows an evaporator typically heated by Main Engine Jacket water with means to supply steam when the engine is shut downSingle and multi stage resistance distillation was one of the early types of fresh water generation. It uses heat spining finished and through submerged coils or subway bundles immersed in sea water to produce the distillate, which when condensed becomes the fresh water.Single Stage Flash Evaporatorflash e evaporationatorit represent of twain parts1.condensor2.evaporatorgenerally the heating method use is main engine heat or by heating oil usually the water boils at vitamin C degree. But in the freshwater generator the water inside(a) the system usually boiled at 60 to 70 degree. By using ejector or edecutor.basically an alternative arrangement to the shell evaporator is the flash evaporator were heating takes place externally, the hot soak enters the low pressure chamber into a weir where some of the water flashes off. Water over runing the weir is either out or enlightened on to a second stage. Multi stage units with to each one stage maintained at a lower pressure discontinue improved efficiency and high outputs. to check into the percentage of salt salinoemetre is used. its is important to use salinometere because if the percentage of salt in water became high then it can detect it and raised the alarmMulti Stage Flash Evaporatorflash flow diagramrin this ferment we use two evaporation stages in order to get a better typical multi stage flash system is base upon preheating of a pressurised sea water stream, or more typically a recycle brine stream to which the collapse sea water is added the stream is heated in the heat input voice brine heater. Double stage FWG is similar to the sin gle stage FWG, the only difference being that the whole single stage process is repeated doubly in 2-stage generator From here the recycle stream is passed into the starting time stage of a series of flash chambers. Here the pressure is released, permitting a portion of the brine stream to flash to form salt-free vaporization which is condensed to give the fresh water. In condensing the vapour gives off its latent heat to the recycle brine stream. From the first stage the news bulletin brine stream is passed to the second stage which is kept at a slightly lower pressure more vapour flashes off. In the same way the flashing brine stream passes to the next stage and so on through the plant with a portion of the vapour flashing off at each stage. A heat balance shows that the heat supplied in the brine heater has to be rejected. This is done in the last two stages of the plant which are cooled by a sea water stream which subsequently passes to waste.Modern Developments.Large Multi- effect Alfa laval evaporatorIn 1990 Alfa-Laval Desalt introduced its D-TU concept-a ME desalination system based on tube type distillers, by using the evaporation under vacuum with the rising film principle. This is thath means the inner surfaces of the tube are ever so covered with a then film of the feed water . heating medium is circulates on the outside of the tubes in the heat exchangerss.and The vacuum is created by water ejectors connected to each effects. A controlled amount of sea water is led to the bottom of each of the effect. where it is mixes with the brine from the previous effect and into the tubes in the heat exchanger, where it is heated. The generated blues enter a separator where the brine droplets from the wet vapour are separated. The dry vapour pass through the separator to the following effect where they condense. The stay sea water which has been converted to brine, flows to the next effect as feed water. The brine is taken out and discharged overboard. Th e latent heat in the megrims from the previous effect is used as a heating medium in the following effects. The process continues until the last effect where the generated vapours condense cooled by sea water. The condensate vapours flow from one effect to the next, and are retained in a collecting tank as distilled water. If a low temperature evaporator is to be used for domestic purposes certain restrictions apply. Operation is not allowed within 25 miles of the coast or 50 miles of an estuary. Chromate jacket water treatment must never be used. The condensate must be treated in order to destroy bacteria. Care must be taken if chemicals are used to inhibit marine growth in pipe work.Vapour CompressionThe boiler section is initially filled with fresh water. When the system is operating feed water is supplied via the level control valve. Hot steam is created in the boiler which passes over into the main section. Here the steam is mixed with a brine spray. roughly of the steam is co ndensed and some of the brine spray is flashed off. The combined steam passes over to the vapour section via a scrubber. Flow of vapour occurs due to the action of the compressor which increases the vapour pressure increaseing its saturation temperature.Reverse OsmosisOsmosis describes the process whereby a fluid will pass from a more dense to a less dense root word through a semi-permeable membrane. It is very important to the water absorption processes of plants. RO is a process which uses a semi permeable membrane which retains both salt and impurities from sea water musical composition allowing water molecules to pass. Filtration of up to 90% is possible thus making the produced water unsuitable for boiler feed without further turn backing. Improved quality is possible using a two or more pass system.diagram showing osmotic headThe parchment paper acts as the semi-permeable membrane and allows the water molecules to pass but not the larger salt molecules.Reverse osmosis is t he process whereby a pressure greater than the osmotic head pressure is applied to a solution of high density. Fluid is forced from the high density side to the less dense side. For desalination plants the pressure is applied to sea water and the water is forced through the semi-permeable membrane.The semi permeable membrane which is typically made of polyamide membrane sheets wrapped in a spiral form near a perforated tube resembling a loosely transgress toilet roll.Design of the cartridges is therefore such that the sea water feed passes over the membrane sheets so that the washing action keeps the surfaces clear of deposits. A dosing chemical is also injected to assist the action.Make up of membraneThe two membranes sealed on the satellite three edges, enclose porous under- work through which the permeate spirals to primeval collecting tubeSchematic of RO plantPressurised feed water passes lengthways through the tubelike spiral wound membrane element. Freshwater permeate tra vels through the membrane layers as directed along a spiral bath inot a central perforated tube, while brine is discharged out the end of the membrane element..The fluid could be water and the solutions sea water. Under normal conditions the water would pass from the less sa hunt solution to the more saline solution until the saltiness was the same. This process will cease however if the level in the more saline side raises to give a difference greater than the Osmotic height.For practical use to allow the generation of large quantities of water. It is necessary to have a large surface area of membrane which has sufficient mechanical strength to resist the pressurised sea water.. The material used for sea water purification is spirally wound polyamide or polysulphonate sheets. One problem with any filtration system is that deposits accumulate and gradually blocks the get across. The sea water is supplied at a pressure of 60bar, a relief pitcher valve is fitted to the system. The Osmosis production plant is best suited to the production of large quantities of water rather than smaller quantities of steam plant feed quality.Pre-treatment and post treatment.Sea water feed for reverse osmosis plant is pre-treated before being passed through. The chemical sodium hexa phosphate is added to assist wash through of salt deposits on the surface of the elements and the sea water is sterilised to remove bacteria which could otherwise become resident in the pick up. Chlorine is reduced by compressed carbon stress while solids are removed by other filters. Treatment is also necessary to make the water drinkable.The disc tube module is supposed to have the main advantage over the spiral wound type in that it avoids the need for the difficult cleaning processes required. With long lasting membranes, typically 5 years and in built cleaning system the unit will recover 30% as pure water from sea water passing through it ringlet or Tube Seawater EvaporatorThis is a modern version of the type used when I was at sea in the 1960s they used heating coils in those days as opposed to the pipe nest heaters of today. The coils used to become carapaced in salt, with the attendant loss in output of distillate. I was in charge of the vaps and I remember the old chief coming down to the engine room on my watch and balling me out for the downturn in distillate. We were having problems with the boiler feed water purity (next article will cover the testing and treatment of boiler feed water) so I was blowing down the boiler regularly with the associated make-up requirement meant we needed more water pronto. Anyway I took him up to the vaps and showed him the scaling on the heating coils, reminding him that I was coreing Foss chemicals into the beast to sweat and break this away. He pushed me aside and shut off the seawater supply opening up the steam supply which rapidly dried the salt layer on the coils. He then opened the seawater inlet and hey presto the sal t scale cracked and fell of the coils. I used this system some(prenominal) times until I was up for Seconds ticket and examiner wasnt too pleased to hear of this method, called the old Chief several unprintable names. Today we dont have to lag to these measures as there is an innovative device which uses a material that emits oscillations counteracting the natural seawater oscillations, thereby altering its properties and preventing calcium carbonate scale. (I will note the website speech communication in the relevant section I am too old for this new technology). A tube and coil evaporator consists of a steel vessel which has a nest of heating pipes near the bottom of the vessel being fed by steam or, hot water from the main engine. There is a tube condenser cooled by seawater installed near the top of the vessel. A vacuum is drawn in the vessel by air ejectors operated by steam or pressurised seawater. Seawater is fed into the evaporator just covering the heating pipes. Heat is supplied to the pipes and, this combined with the vacuum conditions begins to boil the seawater producing steam. The steam rises up through a demister into the tube condenser where it is evaporated to distilled water. This is collected and pumped via the salinometer to the storageEVAPORATOR SCALE.There are numerous types of evaporators all working to produce pure water with concentrated sea-water as waste. This density effect can lead to the formation of damaging scales within the evaporator. Over concentration is usually prevented by having a continuous stream of sea-water passing through the unit thus maintaining a satisfactory dilution of the sea-water side of the evaporator. However, because of the high salt content, when sea-water is elevated to temperatures above 30 C scales can begin to form on heat transfer surfaces. Additionally as the majority of evaporators operate under vacuum there is a tendency for the make-up water side to foam, which can give rise to carry-over an d contamination of the pure water stream.Four scales which are principally found in evaporators areCalcium Sulphate (CaSO4)-1200ppm, scale formation is principally on density, remains in solution below 140oC and/or 96000ppm.The worst scale forming salt forming a thin hard hoary scaleMagnesium Hydroxide Mg(OH)2remains in solution below 90oCMagnesium Bi-Carbonate 150ppmsoluble below 90oC, forms a soft scale, prevention by belongings operating temperature of evaporator below 90oCAbove 90oCbreaks down to form MgCO3 and CO2 and then Mg(OH)2 and CO2Calcium bicarbonate Ca(HCO3)2 180ppmSlightly solube, above 65oC breaks down to form insuluble calcium carbonate forming a soft white scale. scale formation prevented by chemical treatment Ca(HCO3)2 = Ca + 2HCO32HCO3 = CO3 + H20 + CO2If heated up to approximately 80oCCO3 + Ca = CaCO3If heated above 800CCO3 + H20 = HCO3 + OHMg + 2OH = Mg(OH)2Hence if sea water in the evaporator is heated to a temperature below 80oC calcium carbonate predominate s. If it is heated above 80oC then magnesium hydroxide scale is deposited.Sodium Chloride 32230 to 25600ppm -generally ignoredSoluble below 225000ppm forms a soft encrustation, free ions promote galvanic action. It is unlikely to precipitate and is slow removedSupersaturationThis is where the concentration of dissolved salts exceed their solubility at the particular temperature encountered and precipitation begins to occur. When deposition occurs under these conditions heavy scale deposits can rapidly micturate up and lead to a loss of heat transfer efficiency. Scale deposition due to supersaturation is often localised in areas of elevated temperature such as heat transfer surfaces in heat-exchangers. This is because of localised over concentration of salts with respect to the temperature of the thin water layer at the surface of the metal. Scale deposition can therefore occur on heat-exchange surfaces even when the conditions in the bulk of the water are not scale forming.FINALLY SELECTED GENERATORVACCUM VAPOUR COMPRESSION freshwater GENERATORMAKER.. ALFA LAVALTYPE.. ORCA OFFSHORE SERIESCAPACITY20-70m3/per dayvacuum vapour compression is the efficient method of production of fresh water for both drinking and other use. by using this method we can convert the sea water in to fresh water by vacuum distillation process using electricity. The system has simple compact designee made from te heat exchanger plates with combined fresh water and feed water system. the system has low maintance cost any work on start and forget operation .and can produced very high quality of fresh water .BASIC Equipment.titanium plate heat exchanger for the combination evaporator and condenserstainless steel distiller shell,air ejectorfreshwater pumpcompressorUL approved panelbuilt in freshwater quality monitoring system.ADDITIONAL Equipmentfresh water pH adjustment filter.silver-ion or we can say UV sterilisersVACCUME DISTILLATION PROCESS.vacuum distillation is the process use to c onvert sea water in to fresh water. by this process constant supply of fresh water with low coarseness level and be achieved with continuous controlling the water quantity.WORKING PRINCIPAL .0feed water enter in to the lower section of the plate packs.plates is warmed by heating medium, heating medium is either a jacket water cooling medium or a closed circuit heating mediumwater is then evaporated at 40-60 degree centigrade in the vacuum of 85-95 %the vapour produces is raised between the plates in the middle section of plate pack. At this point seawater is almost completely removed.these droplet falls back in to the brain sump by the gravity at the bottom of the fresh water generator.only the clean fresh water can enter in to the condenser section and the water is cooled by flow of sea water. at that point vapour is condensed in to fresh water and pumped out by the fresh water pump.GHARP SHOWS THE % TONS PER DAY PRODUCTIONTechnical specifications (standard units without optional equipment)Water nobleman type ORCA seaward 20 ORCA Offshore 30 ORCA Offshore 40 ORCA Offshore 50 ORCA Offshore 60 ORCA Offshore 70Length (L) mm/inch Width (W) mm/inch Height (H) mm/inchDry burthen kg/lbsOperating weight kg/lbs FW pump motor kW/hpBrine pump motor kW/hpSW pump motor kW/hp (option)Circ. pump motorElectric power (kW installed)Power consumption kwh/m3 fresh water Fresh water qualityDimensions *)THE gulp SHOWS ORCA OFFSHOREE SERIES WITHOUT OPTIONS2450 / 96 2150 / 85 2400 / 943700 / 8175 3865 / 85211.3 / 1.7 1.3 / 1.7 12.5 / 1 1.9 / 2.678.518WHO standard, less than 5 ppm NaCl2800 / 1102150 / 852400/944000 / 8818 4185 / 92261.3 / 1.7 1.8 / 2.4 12.5 / 17 3.6 / 4.98118SLOW SAND FILTER (SSF) FOR THE REMOVAL OF HEAVY METAL. muffled gritrock filters (SSFs) are probably the most effective, simplest and least expensive water treatment process. Micro-organisms and other particulate materials are effectively removed by SSFs. Considerable turn outment has been done on SSFs with respect to particle removal, but only a hardly a(prenominal) works have been reported in the context of the removal of heavy metals which are a severely toxic pollutant of surface waters. No extensive science lab or pilot studies have been carried out to determine the performance or the mechanisms of removal of heavy metals by SSFs. This research is concerned with an experimental investigation of the removal of heavy metals from surface water by SSFs. Four laboratory scale SSFs were built and run according to standard design criteria. Removal of four popular heavy metals copper (Cu), chromium (Cr), lead (Pb) and cadmium (Cd) were monitored. The filters were fed synthetic water made from tap water mixed with settled sewage, and each filter was process with one of the heavy metal salts. The concentrations of Cu, Cr, Pb and Cd in the influent were selected as 10 mg/l, 100 g/l, 60 g/l, and 100 g/l respectively considering their relative toxicity and WHO guidelines in drinking wate r. Settled sewage was added to vary the total primitive carbon (TOC) of the feed water. The diminution of heavy metal concentrations were monitored at various TOCs, filtration pass judgment and filter bed depths. The results showed that SSFs succeeded in removing heavy metals from water. The removals of Cu, Cr, Pb and Cd at the conventional flow rate and filter depth are 99.6,97.2,100 and 96.6 % respectively. The results also showed that an increase in TOC in the feed water improved metal removal while increases of flow rates caused a decrease of the removal of metals. The removal of heavy metals also decreased with a reduction in sand bed depth. The optimisation of design parameters for SSFs for the removal of heavy metals depends on the individual heavy metal and on the TOC content of the feed water. Model equations were developed for, and linear correlation was observed between each of the three control parameters and the removal of the selected metal. The removal of heavy met al by SSFs was achieved through the combination of a number of mechanisms. Settlement, adsorption to both sand and organic matter and microbialWORKING PRCEDUREslow and sand filter work through the formation of a layer know as hypogeal layer or schmutzdecke .hypogeal layer contain microorganism that remove bacteria and trap condiments particles.it consist of bacteria,fungi,portozoa,rotera and a range of aquatic insect larva. the hypogal layer provides effective purification in potable water treatment.as the water passes through the hypogeal layer particles of foreign matter are trapped in the mucilaginous matrix and dissolved organic material is adsorbed and metabolised by bacteria, fungi and protozoa. Water produced form a well managed slow sand filter is free from heavy metals and other hazards. Slow sand filter are simple, are easily used by small systems, and have been adapted to package plant construction . Slow sand filter are similar to single media rapid-rate filters in some respects, but there are crucial differences in functional mechanisms(other than the obvious difference in flow rate) the schmutzdecke removes suspended organic materials and microorganisms by biodegradation and other biological processes, instead of relying solely on simple filtration or physic-chemical sorption. Advantages of slow sand filtration include its low nutrition requirements (since it does not require backwashing and requires less frequent cleaning) and the fact that its efficiency does not depend on actions of the operator. However, slow sand filters do require time for the schmutzdecke to develop later on cleaning, during which the filtration performance steadily improves this interval is called the ripening period. The ripening period can last from six hours to two weeks, but typically requires less than two days. A two day filter-to-waste period is recommended for typical sand filters . Since fewer remedies are available to an operator when the process is ineffecti ve, slow sand filtration should be used with caution and should not be used without pre treatment or process modifications unless the raw water is low in turbidity, algae, and colour . Package plant versions with a granular activated carbon layer located beneath the slow sand filter can absorb organic materials that are resistant plenty to biodegradation to pass through the schmutzdecke. When used with source water of the appropriate quality, slow sand filtration may be the most suitable filtration technology for small systems (6). Slow sand filtration has demonstrated removal efficiencies in the 90 to 99.9999% range for viruses and greater than 99.99% for GuardiaFILTER DISCRUPTION.Square tankMedia depth 2-3 ftSurface area Filtration rate 2-10 gal/min-ft2Flow through filter 350-3,500 gpmBackwash frequency every 24 houreCALCULATIONWe have required maximum 40000 litter per day production per day. and the filtration rate of this filter is max 51000 litter per day which fulfil our requ irement. and we have to put two filter in parellal for the standby and maintaince purpose. So that if one filter stop working we can use the other standby filter to run the system as per requirement.IMPORTANT POINTsthere is one get out line in slow sand filter before the water enter in to the sand filters. and this bypass meet the discharge line of distilled pump. The reason for this bypass is that if the ship is in the sea we can open the bypass valve and the fresh water then straight go to the mineraliser unit. because in the roiling and pitching condition the slow sand filter does not work properlythe sand filter unit is completely fixed with proper fitting. so that when the main engine runs it does not move from his place.one the important is that the system will take at least 2 day to start working .so for days the ship master has to arrange some external sources of drinking water.CLEANING METHODThere is two method of cleaning of sand filter1. the top few millimetres of fine s and is scraped off to expose a new layer of clean sand. Water is then decanted back into the filter and re-circulated for a few hours to allow a new Schmutzdecke to develop. The filter is then filled to sufficient depth and brought back into service2. The second method, sometimes called wet harrowing, involves lowering the water level to just above the Schmutzdecke, stirring the sand and thereby suspending any solids held in that layer and then running the water to waste. The filter is then filled to full depth and brought back into service. Wet harrowing can allow the filter to be brought back into service more quickly. POSITION.we can fit the sand filter before the discharge of distilled pump.CHEMICAL TREATMENT.VAPTREAT.chemical known as vaptreat is add in to the system before the point where sea water is going inside the system .because this chemical make the sea water soft.IMPORTANT PROPERTIESOdour OdourlessAppearance Liquid, pale yellow, soluble in waterContact with look Mild ly irritating to eyesContact with skin In cases of severe exposure, irritation may developInhalation Vapours or aerosols may cause irritation of eyes, nose and respiratory tractIngestion May cause gastro-intestinal disturbancesMINERALISER AND CHLORINE UNITAfter the discharge of distilled pump the water then pass through the mineraliser after the mineraliser chlorine is added to the water.capacity of mineraliser=3800liter/hourcapacity of chlorine unit.=3800liter/hourPUMPS REQUIREMENTSEjector PumpThe ejector pump is a single-stage centrifugal pump which supplies thecondenser with sea water and the brine/air ejector with jet water as well asfeed water for evaporation.Fresh Water/Distillate PumpThe single-stage centrifugal fresh water pump extracts the distillate from thecondenser and pumps it to the fresh water tank.POSITION OF EJECTOR PUMPThe pump is fitted after the suction of low sea chest. because at the low sea chest suction there is no oil present .and is the best point of winni ng the main sea water suction .TYPE OF PUMP.TEHNICAL DATACASING.. Cast iron, Nodular cast iron, Bronze, Stainless steelIMPELLER.. Cast iron, Bronze, Stainless steel utmost CAPACITY.850m3 per hourMAXIMUM DELIVER HEAD105MMAXIMUM LIQUID TEMPERATURE120 CENTIGRADEMAXIMUM PRESSURE.1000KPaMAXIMUM SPEED3600 rpmSalinometerThe salinometer continuously checks the salinity of the produced water.The alarm set point is adjustable. salinometer continuously check the quality of the distillate, a salinometer is provided at the outlet side of the distillate pump.If the salinity of the produced fresh water exceeds the chosen maximum value,the solenoid valve is activated to automatically dump the distillate to the bilgeand an alarm is soundedControl PanelThe control panel contains motor starters, running lights, salinometer andcontacts for remote alarm.DISTILLED WATER TRANSFER AND DISTRIBUTIONEach fresh water generator distillate pump discharges through a salinometerand a flow meter. Positioned before the flow meter is a solenoid valve. Thisopens when the salinometer detects too high a salinity level, diverting thedistillate pump output to the bilge.The discharge from the FW generators flows to either the distilled water tankwhich is situated in the steering gear room on the channelize side though inletvalve or to the fresh water tanks which are both situated on the port and starboard sides of the steering gear room.The distilled water tank supplies water to the boiler feed water tank via valveFresh water produced in the generator that is to be used for domesticpurposes is directed through a mineraliser and a chlorination sterilising unitbefore entering the fresh water tanks. The fresh water tanks supply water tothe d