IAEA Workshop Decontamination of Tubings

Transcription

1 IAEA Workshop Decontamination of Tubings Prof. Dr.-Ing. Sascha Gentes KIT University of the State of Baden-Wuerttemberg and National Research Center of the Helmholtz Association

2 Overview Naturally Occurring Radioactive Material (NORM) Development of scales inside tubing Classification and composition of contaminated deposits Currently used decontamination technologies Decontamination of tubings using vibration Analyses and simulation of scales Tool carrier and influencing factors on force, acceleration and frequencies Decontamination tools Feeding device and jig Investigations Preliminary investigation results Main Investigation Conclusions 2

3 Naturally Occurring Radioactive Material NORM (Naturally Occurring Radioactive Material) Uranium, Thorium, Potassium and its decay products Occurrence of Norm-Material metallurgical industry processing of phosphate ore preparation drinking water purification petrochemical industries TENORM (Technologically Enhanced Naturally Occurring Radioactive Materials) Material whose radionuclide concentrations or potential for human exposure have been increased above levels encountered in the natural state by human activities. 3

4 Development of scales inside tubing Removal and transportation of radionuclides and ions Decrease of solubility of materials inside the liquid because of change in temperature, pressure and ph-value Precipitation of NORM and other materials and accumulation in tubings and other installations of a petrochemical facility Compounds of Barium, Calciumsulfat, Calciumcarbonat, Strontium, Radium Scales Oil, Brine Ca+ Ba+ Ra 228 Sr+ Ra+ Ba+ Ca+ Sr+ Ra+ Ra 228 PB 210 HG PB 210 HG SO- PO- HCO- F- Ra 226 U 238 Th-232 Po210 Ra 226 F- SO- PO- HCO- 4

5 Classification and composition of contaminated deposits Classification of contaminated deposits from the exploration of oil and gas Sludges Scales (highest concentration of radioactivity) produced water Composition of the Scales Radioactive Materials ( radium, lead, polonium) Toxic Materials (mercury, heavy metals) Consistency Compounds of sulfate und carbonate hard, brittle and dry thickness: up to several millimeters Scales inside tubings used in exploration of naturals gas 5

6 Currently used decontamination technologies Abrasive-blasting Wet (Jet Blasting) Dry (Sand Blasting) Sandblasting of tubings Decontamination of 7km of tubing are causing 30t - 50t of sludges. Dry mass of scales of 7km of tubing are approx.: 15t Triplication of the contaminated materials through secondary waste Sandblasting of tubings Decontamination of Tubings

7 Scales from exploration of natural gas 7

8 In-situ measuring of scales Hardness according to mohs: 2-3 Impact tests Determined thickness of scales, generally: 1-3 mm 8

9 Simulation of scales The hazardous nature of the contaminated scales complicates the investigation Simulation of scales with similar but uncontaminated materials of the same consistency allows an easy handling Challenges: Determine of the mechanical and physical properties and finding proper classification units Hardness Consistency (brittleness, bond strength) Determination of thicknesses Finding of similar material and simulation of different thicknesses inside the tubings 9

10 Simulation of scales Inorganic material Plastic-modified cement polyester-based two-component filler Cements with different Hardness Classification of the scales Measuring of hardness, elasticity and plasticity and bond strength 50 mm 20 mm 10

11 Simulation of scales Application of materials in tubes consiting of two exact halves Rotation of the tubes with scales Dry season 11

12 Decontamination using vibration Tubing Contaminated Scales Feed Force Tool carier Vibration Tool 12

13 Tool carrier Unbalanced mass (1) supported inside a tube (2, 3) Connected via a flexible shaft to an electric motor Freely adjustable rotation speed up to rev/min Vibration and rotation of the tool carrier Source: wackerneuson.com 13

14 Influencing variables for force and acceleration Acceleration Force Rotation: 2 a = e Ω F = m a cos ( Ω t) Ω F e Force: Ω( t) F(t) F( t) = m e Ω 2 cos( Ω t) m e Increase of the occurring force through: Increase of the rotational speed quadratic influence Increase of mass is not always the point, given space conditions can result to a lower eccentricity and therefore a lower force 14

15 Different frequencies at the same energy level H 45S H m/s² Acceleration [m/s²] 839 m/s² 253 m/s² 13 Hz Frequency [Hz] 15

16 Relationship between frequency and acceleration Acceleration [m/s²] Frequency [Hz] 16

17 Force measurement on the tube shear force sensors Force measuring in two different directions Force in X - direction Force in Y - direction Force [N] Rotational speed level [Hz] Rotational speed level [Hz] 17

18 Tool geometry Possible forms of contact between tools and scales: pointed linear flat Factors of influence of a tool with edged geometry Edge angles Flank angle α β Direction of arrangement of the edges (longitudinal, radial, oblique) Length, height and diameter of the tool Number of edges α b β h 18

19 Decontamination tools 19

20 Wear signs on the tool after decontamination application and improvement options 20

21 Feeding device and Jig Adjusting Screws Changing of gear ratio Driving roller Flexibel Shaft 21

22 Removal of Scales ablation process 22

23 Before and after 23

24 Preliminary investigations to determine the tendency of the influencing factors v = 13 cm/s, 2 cm/s Scale thickness = 2 mm Influence of the frequency at feed rate of v = 13 cm/s Factor 8 Influence of the frequency at feed rate v = 2 cm/s Factor 2 6 experiments in total needed to remove 97 % of the scales Tube 1 24

25 Preliminary investigations to determine the tendency of the influencing factors v = 2 cm/s Scale thickness = 2 mm Influence of the frequency at the feed rate of v = 2 cm/s Factor: 8 Only two experiments in total needed to remove up to 89% of the scales Tube 2 25

26 Main Investigations Determination of the influences of the variables Frequency Feed rate/ feeding force Scale thickness Scale hardness Tool geometry Tool carrier Tubing diameter Main target: Removal performance Decontamination speed Complexity / Efficiency Wear Development of a model to combine all the different influences between the parameters. 26

27 Conclusions Environment-friendly decontamination without secondary waste Prevention of an accumulation of contaminated dust Saving of valuable resources Automated decontamination process Challenges: Determining the effects of the parameters Increase efficiency of the decontamination process 27

28 Thank you for your attention! 28