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The JPCHEMICAL
The JPChemical legendThe JPChemical cleaning servicesLinks in GreeceLinks in the Far East Region(ELLHNIKA) Articles in Greek LanguageMARINE BOILERS REPAIRS LTDMARINE BOILER REPAIRSRULES AND REGULATIONSFIELDS
PlantsOil refineriesPower plantsMarine and ShippingInstallationsIMAGESBoilers. Definitions, Types & TerminologyHRSGHeat ExchangersPipelinesMaterialsIron & Carbon SteelStainless SteelObjectsCupreous metalsCoins and MedalsBuildingsMasonry buildingsCHEMICAL CLEANING AGENTS
Which materials & equipment?Acid CleanersAlkaline CleanersPassivation ChemicalsPumpsTesting and MonitoringSAFETY FIRSTSafety in Chemical CleaningSpill Cleanup RespondMSDS Hydrochloric AcidMSDS of Citric acidMSDS Ammonium bifluorideMSDS of Nitric AcidMSDS Caustic sodaMSDS Ammonium Hydroxide (10-35% )MSDS Trisodium phosphateMSDS of Sodium CarbonateMSDS of Sodium MetasilicateMSDS of Sodium NitriteCHEMICAL CLEANING TUTOR
Chemical Cleaning terminologySpecificationsCommon MistakesTo clean or not to cleanThe sequenceThe ChemistryGlossaryCHEMICAL CLEANING PARAMETERSChemistry UnitsConcentration unitsPhysics and chemistry unitsFlow RatesMathematics unitsWater Treatment|
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| Velocity and Volume Flow Rates In Chemical Cleaning, m/sec amd m3/hour |
| 1) Flow rates. 2) Volume Capasity of Pipelines in various sizes |
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| Principle Flow of a fluid can be expressed in terms of its velocity, its instantaneous volumetric or mass flow rate in terms or the total quantity passed (either volume or mass) in a given time. Velocity Fluids do not move at the same velocity at all points across a pipe - generally they move faster in the centre and slower near the walls. Thus the velocity of the fluid can be either its velocity at a given point (e.g. at the centre of the pipe etc.) or its average velocity. The SI unit for both point and average flow velocity measurement is metres/second. (m/s) Excessive velocity during chemical cleaning often leads to erosion corrosion. Generalized corrosion can proceed at accelerated rates if velocity is excessive. Velocity threshold values for erosion corrosion are often greatly reduced in boiler materials of construction at elevated temperatures and in the presence of solvents. Conversely, an insufficient velocity can result in improper chemical cleaning because a low velocity may not allow fresh chemical cleaning solvent to contact deposit/scale for purposes of promoting dissolution. Velocity during Chemical Cleaning of a Boiler Fluids do not move at the same velocity at all points across a boiler - generally they move faster in the small pipes like tubes centre and move slower near the big pipes as headers and drums. Thus the velocity of the chemical cleaning fluid can be either its velocity at a given point or its average velocity. The SI unit for both point and average flow velocity measurement is Meters/second. (m/s) Volumetric Flow Rate Volumetric Flow Rate = Average Velocity x Cross section Area of Pipe V=v x A Where: · Volumetric flow rate ( /s) · v = Average velocity (m/s) · A = Cross sectional area of pipe ( ) Taking in consideration an internationally accepted handbook as the ‘ HEAT TRANSFER AND FLUID SERVICE HANDBOOK’ 1991 HTFS, it is suggested to acid clean a boiler at circulation flow ranges of velocity 0.3-1.0 m/sec and finally to proceed in final flushing / rinsing at velocities greater than 1.8 m/sec in the largest cross-sectional area. This considered vital in chemical cleaning success, since only a small proportion of the material removed from the wall during chemical cleaning actually dissolves, the majority remaining as particles of deposits of varying sizes. Pipe/tube diameter in inches………..10..…8...….6……4…..2….1,5…….1….3/4 Diameter...in cm ......................…….25.…20…..15….10…..5…..3.75….2.5…1.875 Cross-sectional area cm2………….490.. 314…176…78,5..19.6…11…..4,9….2.75 (I) For flow velocity m/s 0.3 in 10'' tube (the minimum for Chemical Cleaning) the equivalent flow velocity in various sizes of tubes is.....................………0.3…0,47..0,83…1,87..7,50..13,36…30….53 Equivalent Volumetric flow is m3/hour 53 (pump needs) (II) For flow velocity m/s 1 in 10'' tube (the maximum for Chemical Cleaning) the equivalent flow velocity in various sizes of tubes is.....................……….1…1,56…2,78….6,24…25….44….100…176 Equivalent Volumetric flow m3/hour 176(pump needs) Pipe/tubes sizes and Volumes Pipe volume in m3 according to size in inches Formula: V= 3,14xd2x L/4 V= volume in m3 D= pipe diameter in m L= length in m 1’’….…..02,5cm=…..0,025m….….0,060m3/100m 2’’….…..05,0cm=…..0,050m….….0,190m3/100m 4’’……...10,0cm=…..0,100m….….0,780m3/100m 6‘’……...15,0cm=…..0,150m….….1,760m3/100m 8’’……...20,0cm=…..0,200m….….3,140m3/100m 10’’…….25,0cm=…..0,250m….….4,900m3/100m.…….0,490m3/10m 12’’…….30,0cm=…..0,300m….….7,060m3/100m.…….0,706m3/10m 14’’…….35,0cm=…..0,350m….….9,610m3/100m.…….0,961m3/10m 16’’…….40,0cm=…..0,400m…….12,600m3/100m.……1,256m3/10m 18’’…….45,0cm=…..0,450m…….15,890m3/100m.……1,589m3/10m 20’’…….50,0cm=…..0,500m…….19,620m3/100m…….1,962m3/10m 22’’…….55,0cm=…..0,550m…….23,740m3/100m…….2,374m3/10m 24’’…….60,0cm=…..0,600m…….28,960m3/100m…….2,826m3/10m 32’’…….80,0cm=…..0,800m…….50,240m3/100m…….5,024m3/10m 60''...........150..cm= ...1,500m.........176,00m3/100.m......17,65m3/10m |
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