NORM in Geothermal Projects for - PDF document

1 NORM in Geothermal Projects for Greenho
NORM in Geothermal Projects for Greenhouse Horticulture (NL) Gert Jonkers Lonneke van Bochove Independent Consultant Stralingsupport BV NORM formation and options for reduction Gert Jonkers (presenter) & Lonneke van Bochove September 2019 1 GeJo (TE)NORM September 2019 2 GeJo ( TE)NORM OUTLINE – Geothermal NORM 1. Setting the Scene – Geothermal Energy 2. Geothermal Greenhouse Heating & NORM – Schematics 3. Implementation of EC Directive 2013 / 59 Eura

2 tom 4. Reducing NORM Production Septembe
tom 4. Reducing NORM Production September 2019 3 GeJo ( TE)NORM 1 Setting the Scene Geothermal Energy September 2019 4 Geothermal Family GeJo ( TE)NORM Ground Source Heat Pumps (GSHP) Vertical (or Horizontal) ( 100 m); Limited Power 100 kW th ; 1000 ’ s installed, individual houses Heat/Cold Storage Aquifer Thermal Energy Storage “ Shallow ” Aquifers; up to 250 m (T = 5 – 30 ° C); Power 0.1 – 10 MW th ; ~ 1000 installed (mainly heating/co

3 oling offices); 1 – 3 M€ ‘ Deep
oling offices); 1 – 3 M€ ‘ Deep ’ Geothermal Energy (direct use) Doublets (close loop, heat transfer via heat exchangers), Depths from 1000 m (T from 40 ° C); ~ 10 installed 5 – 20 M€ ‘ Ultra - Deep ’ Geothermal Energy Systems (Enhanced Geothermal Systems)/Hot Dry Rocks Depths from ~ 3500 m; Temperatures from 100 ° C; � 100 M€ Crust Core Mantle September 2019 5 Energy Consumption & Generation the Netherlands ( 2010 d

4 ata) GeJo ( TE)NORM the Netherlands cons
ata) GeJo ( TE)NORM the Netherlands consumes 3,500 PJ/year • 38 % heating with T � 100 o C, • 30 % heating & cooling with T 100 o C, • 20 % transport, and • 12 % electricity. Dutch energy demand generated by combusting fossil fuels. • 9.1 % Coal • 37.2 % Oil • 47.1 % Natural Gas remainder nuclear power and renewables ( 3.8 %) 90 % of the total heat demand provided by Natural Gas costs of products from greenhouse horticulture: 20 t

5 o 30 % due to energy (natural gas) co
o 30 % due to energy (natural gas) consumption September 2019 6 Geothermal Heating of Horticulture Greenhouses - Principle GeJo ( TE)NORM greenhouse heating by fresh water circuit separated from source water geothermal heat ( 80 – 100 ° C) transferred from hot formation water pumped from 2 to 3 km depth greenhouses exchanger: transfers heat from formation water to fresh water no transfer of Naturally Occurring Radionuclide ’ s (NOR ’ s) from sou

6 rce water to fresh water circuit NOR â€
rce water to fresh water circuit NOR ’ s dissolved in source water: 226 Ra, 222 Rn, 210 Pb, 228 Ra & 224 Ra September 2019 7 GeJo ( TE)NORM 2 Geothermal Greenhouse Heating & NORM – Schematics September 2019 8 Geothermal Doublet - Wells GeJo ( TE)NORM Geochemistry – hot water pumped up (heat insulated well head = producer ): ➢ hot (T = 80 - 100 o C ) brines (Total Dissolved Solids � 35 g/L) in chemical equilibrium with rock forming min

7 erals, so many elements (as cations not
erals, so many elements (as cations notably [Pb 2 + ], anions) are present, incl. NOR ’ s. Also low Z elements present as complex anions ( e.g. HCO 3 - ), but virtually no SO 4 2 - . ➢ Starting a new well as soon as possible after drilling co - produced reservoir material shows 11 Bq [ 210 Pb]/g[ ‘ sand ’ ] Proces sing (next slides) Geochemistry – cooled water going down (non - insulated well head = injector ): ➢ cool (T = 20 - 30 o C ) brines

8 with some diminished elemental concent
with some diminished elemental concentrations (due to processing) September 2019 9 Processing of Geothermal Waters – Gas Separation GeJo ( TE)NORM Process chemistry - gas removal, change in pressure, temperature • dry CO 2 is not corrosive, but CO 2 in combination with water creates an acidic environment � corrosion of iron pipe work � pH decreases to ~ 5.5 • at the iron/liquid interface, an anodic reaction may oxidise Fe according Fe(s)

9 + CO 2 + H 2 0 - � Fe 2 + + 2 H
+ CO 2 + H 2 0 - � Fe 2 + + 2 HCO 3 - + H 2 • P and/or T changes will change solubility product of scale forming minerals – suspended/deposited particles (baryte BaSO 4 , galena PbS, laurionite Pb(OH)Cl) September 2019 10 Geothermal Installation – NORM ( 1 ) Scale Formation by (super)saturation GeJo ( TE)NORM • Group II cations (Mg 2 + , Ca 2 + , Sr 2 + , Ba 2 + and Ra 2 + ) present in source water, but in low concentrations • Complex anions (

10 CO 3 2 - , SO 4 2 - ) present in source
CO 3 2 - , SO 4 2 - ) present in source water, but in (very) low concentrations so, ➢ NO (super)saturation by exceeding solubility product of group II carbonate or sulphate salts ( “ scale ” ) ➢ NO inclusion of Ra 2 + ions in the ionic lattice of group II carbonate or sulphate salts ( “ radioactive scale ” ) baryte scaling September 2019 11 Geothermal Installation – NORM ( 2 ) Formation of Suspended Particles by Electro - Chemical Reaction GeJo (

11 TE)NORM Pb 2 + - ions - present in sou
TE)NORM Pb 2 + - ions - present in source water (ppm) - are able to oxidize metallic Fe via a so - called electro - chemical supersession reaction; more noble metal (Pb) is deposited and lesser noble metal (Fe) is dissolved according to Fe(s) + Pb 2 + → Pb(s) + Fe 2 + ➢ small Pb particles (incl. 210 Pb) entrained/suspended in aqueous flow bore plan view cross section flow direction pitting corrosion O ring scales bore Iron (cast) W

12 elding seam Steel pipe ( drawn ) O rin
elding seam Steel pipe ( drawn ) O ring deposits hot brines (T = 80 - 100 o C ) may contain suspended reservoir particles if brine comes into contact with iron (Fe) lead (Pb) micro - particles may be formed, that become entrained in the aqueous brine flow (previous slide) coarse filtering – bag filter unit fine filtering – candle filter unit loading clean bags dirty filter unit folded paper removed filter dirty removed bags Pb stab contaminated by 210 P

13 b no contamination by NOR ’ s Septembe
b no contamination by NOR ’ s September 2019 12 Processing of Geothermal Waters – Suspended Solids GeJo ( TE)NORM September 2019 13 Geothermal Water - Heat Exchangers GeJo ( TE)NORM photographs top: heat exchangers in operation bottom left: dismantled plates source water side bottom right: dismantled plates fresh water side • corrugated plates diverting flow directions with separated hot source water (brine) flow and fresh water (heat transfer to gree

14 nhouses) flow compartment • brownish
nhouses) flow compartment • brownish colour of hot water side due to the applied corrosion inhibitor • dark brown spots (salt crystals) due to drying of plates after dismantling • blackish colour of the fresh water flow side due to applied (other) corrosion inhibitor • no enhanced contamination c.q . radiation levels detected on the dismantled plates September 2019 14 Typical NOR concentrations found in Geothermal Facilities GeJo ( TE)NORM Materiaa

15 l 226 Ra eq Bq/g 210 Pb eq Bq/g 228 Ra
l 226 Ra eq Bq/g 210 Pb eq Bq/g 228 Ra eq Bq/g 228 Th eq Bq/g tubing deposits 4 * 1600 1.9 * 1.6 * filter bag # 0.24 * 2350 0.08 * 0.04 Filter deposits 0.8 * 50 0.06 * 0.06 * * MDA = Minimal Detectable Activity # including filter material Red Highest value found in the Netherlands Green Average value (range 15 to 1000 Bq /gr) N.B. subscript eq denotes: relevant subseries is in secular ( 226 Ra eq , 210 Pb eq , 228 Ra eq , 228 Th eq ) or transient ( 228 Th

16 eq ) equilibrium with their short - liv
eq ) equilibrium with their short - lived (t ½ 1 week) daughters September 2019 15 GeJo ( TE)NORM 3 Implementation of EC Directive 2013 / 59 Euratom September 2019 16 1 . Exorbitant Rise in Filter Bag Disposal Costs GeJo ( TE)NORM February 6 , 2018 (Directive 96 / 29 Euratom) Disposed of by 3 distinct companies: Activity Concentration 300 – 900 Bq [ 210 Pb]/g Amount 9 000 kg Disposal costs € 1 500 per tonne Total costs € 13 500 � Februa

17 ry 6 , 2018 (Directive 2013 / 59 Eu
ry 6 , 2018 (Directive 2013 / 59 Euratom) Disposed of by 12 distinct companies: Activity Concentration 1 – 10 Bq [ 210 Pb]/g Amount 6 700 kg Disposal costs € 1 500 per tonne Activity Concentration � 10 Bq [ 210 Pb]/g Amount 28 500 kg Disposal costs € 2 000 per 60 kg Total costs € 960 000 September 2019 17 2 . Radiological Risks Pb stab / 210 Pb eq Deposits ( 1 ) GeJo ( TE)NORM The Dutch Association of Geoth

18 ermal Operators (DAGO) had a study carr
ermal Operators (DAGO) had a study carried out into the radiological risks of lead ( Pb stab / 210 Pb) deposits for workers, public and environment in a “ from cradle to grave ” (cf. EC Radiation Protection 122 part 2 ) Scenario ’ s included: - all work in the drilling/mining phase • maintenance (filter exchange, any work on flow lines & heat exchangers) • well intervention - waste handling within different waste companies • vacuum distillation

19 • bulk / pyrolysis • incineration
• bulk / pyrolysis • incineration • decontamination • landfill Pb stab / 210 Pb eq denotes a deposit of stab le Pb - isotopes contaminated by 210 Pb radionuclides in secular eq uilibrium with 210 Bi and 210 Po September 2019 18 2 . Radiological Risks Pb stab / 210 Pb eq Deposits ( 2 ) GeJo ( TE)NORM Results ➢ specific exemption for 210 Pb eq up to 100 Bq /g is an option • all handlings with 210 Pb eq contaminated material are justified •

20 handlings intrinsically safe even in cas
handlings intrinsically safe even in case one is unaware of the presence of 210 Pb eq • radiological risks are very low: - occupational dose to all workers less than 50 µ Sv /annum - public dose less than 10 µ Sv /annum • optimisation due to DAGO / NOGEPA standard operational procedures and waste regulation • ADR (implementation of the IAEA Regulations for the Safe Transport of Radioactive Material ) is not applicable NOGEPA = Dutch Oil & Gas Explor

21 ation and Production Association Septemb
ation and Production Association September 2019 19 Effects of Implementing More Stringent Exemption Levels GeJo ( TE)NORM pre - 2018 100 Bq [ 210 Pb eq ]/g[material ] (Directive 96 / 29 Euratom EC RP 122 b) 2018 1 Bq [ 210 Pb eq ]/g[material] (Directive 2013 / 59 Euratom) 1 . Increasing Costs a) Every operator needs to apply for a licence b) Supervision needed always (additional workers to be trained as RPS) c) Almost all waste “ radioactive ” d) Disp

22 osal routes very limited and expensive 2
osal routes very limited and expensive 2 . Low dose/risk for 210 Pb below 100 Bq [ 210 Pb eq ]/g[lead] remains 3 . EL cannot efficiently be measured on - site with a contamination monitor Determining the risk of exceeding limit not possible in a direct way Dispersion into the environment not detectable All waste must be analysed prior to disposal Workers get confused about actual risk September 2019 20 GeJo ( TE)NORM 5 Reducing NORM Production September 2019

23 21 Limiting Options for Electro - Chemic
21 Limiting Options for Electro - Chemical Reactions ( 1 ) GeJo ( TE)NORM Injection of corrosion inhibitor inhibitor molecules adsorb (with their reactive side) on reactive sites of tubulars, flow lines and/or installation parts, by which the reactive sites become blocked. ➢ electrochemical exchange Fe � Pb prevented ➢ protection against oxidation of the inner walls of the installation before  2000 Bq [ 210 Pb eq ]/g[deposit] 2000 kg/a after

24  1000 Bq [ 210 Pb eq ]/g[deposit]
 1000 Bq [ 210 Pb eq ]/g[deposit] 250 kg/a September 2019 22 Limiting Options for Electro - Chemical Reactions ( 2 a) GeJo ( TE)NORM Carbon steel pipework and installation parts as far as possible replaced by materials not eligible for electro - chemical supersession of Fe and Pb: - GRE (Glass Fibre Reinforced Epoxy) - Stainless steel (AISI 316 ) - Polypropylene Tubulars (vertical pipes) may be coated with ‘ polymer ’ September 2019 23 Limitin

25 g Options for Electro - Chemical Reactio
g Options for Electro - Chemical Reactions ( 2 b) GeJo ( TE)NORM View inside GRE tube after one year of service NO inner surface contamination detected September 2019 24 Conclusions GeJo ( TE)NORM • Geothermal operations in the Netherlands ( 2018 ) generate about 30 tonnes of NORM waste, mainly in the form of 210 Pb eq contaminated filter bags • The implementation of the generic exemption level for 210 Pb leads to exorbitant costs for sustainable, but mar

26 ginal geothermal operations • Though a
ginal geothermal operations • Though a graded approach is advertised by the competent authority, despite the very low radiological risk of 210 Pb in practice specific exemption seems yet to be unmanageable • Geothermal operators work on options to reduce NORM generation September 2019 25 Acknowledgements GeJo ( TE)NORM Lonneke van Bochove Radboud Vorage Wart van Zonneveld September 2019 GeJo (TE)NORM 26 Q&A Thank You G.Jonkers 5 @ UPCmail.nl Tel + 31 6 4557