A Feasibility Study - Aaltodoc - Aalto-yliopisto

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The relative roughness is a dimensionless number which gives the ratio between the roughness of the surface and the inner diameter of the pipe. The Reynolds number is also a dimensionless number which describes the type of flow, whether it is laminar (smooth and calm) with a low Reynolds number or turbulent (violent and chaotic) with a high Reynolds number. The equation describing the Reynolds number is where is the dynamic viscosity of water, which is 1,0049∙ 10 - kg/ms at 20 ºC. Pressure losses also arise always when the geometry of the pipeline changes e.g. at the intakes, outlets, valves or divisions of the pipes. A standard way to calculate the pressure loss in each case is to use the formula where is the loss coefficient for various geometric changes, easily obtainable from the literature for different cases. A pipeline can have numerous changes in its geometrics, each contributing a small pressure loss. Therefore the following principle is usually applied. Combining Equations 4 and 7 gives the following Thus the pressure loss from each change in geometrics can be converted to a pressure loss due to travelled distance. Furthermore, all pressure losses resulting from changes in the geometrics can be summed up giving 38 (6) (7) (8) (9) ∑ (10)
where is the equivalent length, causing the same pressure loss as the various geometric changes. In conclusion, the pressure loss in a pipeline can be calculated from where the first factor signifies the pressure change due to change in elevation, the second factor signifies the pressure loss due to friction and the third factor signifies the pressure loss from changes in the geometrics of the pipeline. 8.3 Rerverse osmosis Reverse osmosis (RO) is currently the leading desalination technology and also the salt separation method chosen for <strong>Aalto</strong>RO. The operating principle of RO was described in detail in Chapter 5.2. As a brief summary, it utilizes the osmosis phenomenon, a semipermeable membrane and pressure to separate various ions from water. RO facility usually consists of four major components: pre-treatment, semipermeable membranes, post-treatment and energy recovery. Pre-treatment ensures the safe operation of the membranes by removing sufficient amounts of harmful components from seawater. Membranes do the actual separation of salt ions and water molecules, producing permeate (fresh water) and concentrate (brine, water with a high level of salts). Post-treatment ensures that the water is safe for drinking by e.g. adjusting the pH. Energy Recovery Device (ERD) utilizes the pressure that is still left in the concentrate thus improving the energy efficiency of the entire system. 8.3.1 Pre-treatment The main goal of the pre-treatment system is to produce sufficient quantities of adequate quality seawater for the reverse osmosis (RO) membranes. The seawater incorporates many substances that can be harmful for the RO membranes, e.g. particulates, suspended solids and microbial contaminants. (Voutchkov 2010). Pretreatment must remove sufficient amounts of these foulants, so that no excessive damage or loss of performance is experienced by the RO membranes. Therefore, designing an optimum pre-treatment system is one of the most challenging tasks in desalinating seawater (Wetterau 2011). Pre-treatment can be categorized into two methods: conventional and membrane pre-treatment. The two are not exclusive and can include sections from each other. 39 (11)
Page 1 and 2: Department of Energy Technology Mar
Page 3 and 4: Tekijä: Markus Ylänen Työn nimi:
Page 5 and 6: Table of Contents List of symbols .
Page 7 and 8: List of symbols a Amplitude m cs mo
Page 9 and 10: 1 Introduction 1.1 Framework “Wat
Page 11 and 12: LITERATURE REVIEW 2 Ocean Waves Wav
Page 13 and 14: Figure 2. How waves interact with e
Page 15 and 16: Analyzing waves and their movement
Page 17 and 18: 2.3 Wave energy resource The global
Page 19 and 20: 3 Fresh water The fresh water situa
Page 21 and 22: 3.2 Water usage and price Water usa
Page 23 and 24: 4 Electricity - availability and co
Page 25 and 26: Cost of electricity ($/kWh) 80 70 6
Page 27 and 28: 5 Desalination The importance of de
Page 29 and 30: collected as the product water and
Page 31 and 32: early 1970s (Buros 2000). This also
Page 33 and 34: Figure 19. Filtration capabilities
Page 35 and 36: Figure 21. Possible combinations of
Page 37 and 38: 5.3 Desalination market At present,
Page 39 and 40: 6 Concluding remarks In the Literat
Page 41 and 42: 8 AaltoRO concept The main purpose
Page 43 and 44: In practice, WaveRoller resembles a
Page 45: 8.2.3 Pressure loss Due to the fact
Page 49 and 50: Figure 29. UF pre-treatment. Adapte
Page 51 and 52: additional sheet of plastic which a
Page 53 and 54: 8.3.3 Post-treatment The permeate f
Page 55 and 56: flow rates. However they generally
Page 57 and 58: 9 Case study A case study will be p
Page 59 and 60: Figure 35. ROSA Feedwater Data -scr
Page 61 and 62: Lastly, an economical evaluation is
Page 63 and 64: 9.3 Determining an optimum pressure
Page 65 and 66: Load factor 1 0,9 0,8 0,7 0,6 0,5 0
Page 67 and 68: Recovery (%) 50 45 40 35 30 25 20 3
Page 69 and 70: Cost of water (€/m³) 1,6 1,4 1,2
Page 71 and 72: Cost of water (€/m³) 5 4,5 4 3,5
Page 73 and 74: With the nominal pump capacity of 0
Page 75 and 76: 10 Results and discussion The objec
Page 77 and 78: Figure 53 represents the relationsh
Page 79 and 80: Table 10 presents some figures on t
Page 81 and 82: impediments commencing out of imper
Page 83 and 84: 11 Conclusion This thesis presented
Page 85 and 86: Burger, D. 2011, "Energy and Water"
Page 87 and 88: EPA 2009, 2006 Community Water Syst
Page 89 and 90: Hicks, D.C., Pleass, C. & Mitcheson
Page 91 and 92: Nexus Energia 2011, Canary Islands
Page 93 and 94: Water Corporation 2011, Desalinatio
Page 95 and 96: 14 Appendix B Figure B.1. Site 1 Pe
Page 97 and 98:
Figure B.5. Site 3 Performance curv
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