Hydrochemistry and energy storage in aquifers - NHV.nu

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10°C between two cycles. We have to realize that at a certain distance, due to a gradual expansion of the sphere of influence, the lowest level as well as the top level of the temperature fluctuations raise. But in the mean time the initial temperature regime is transferred to an area at a larger distance from the 'hot' well. This creates a situation of different temperature regimes distributed throughout the aquifer related to the distance to the 'hot' well. Although the temperature levels are considerably lower, the same phenomenon of temperature fluctuations applies to the area around the 'cold' well. The aquifer is not a homogeneous sand body (as shown in Figure 3), therefore, the temperature zones are not symmetric around the wells. As shown in Figure 7, based on observations during cold storage at the national test facility, the distribution of these temperature zones in the aquifer becomes erratic. HYDROCHEMICAL AND MICROBIOLOGICAL ASPECTS As a result of the chemical interaction between groundwater and the surrounding sediment material, groundwater contains a wide variety of dissolved inorganic chemical constituents in various concentrations. The solubility of the minerals depends upon temperature. Changes in temperature will result in shifts in chemical equilibrium, resulting in a possible dissolution or precipitation of elements. An important equilibrium reaction for Dutch aquifers is: T> In reality the equilibrium is influenced as well by the presence of other minerals as by specific combinations of minerals. The microbiological equilibrium conditions as well are disturbed by a (sudden) change of temperature, by periodic temperature fluctuations, by the change of groundwater composition or by the increased groundwater flow. This may result in bacterial growth and slime production, or in bacterial mediated iron precipitation and metal corrosion by sulphate
educing bacteria. These activities decrease groundwater quality in a serious way. CORROSION AND SCALING Scaling occurs due to the disturbance of the hydrochemical equilibrium and a change in mineral concentration, oversaturation and hence precipitation occurs consequently. A change in hydrochemical composition may also create a fluid which is more aggressive with consequently an increased risk of rapid corrosion of the installation. The technical and economical performances of an aquifer thermal energy storage system are very sensitive to the consequences of corrosion and/or scaling. Corrosion of screens, casing, pipes and heat exchanger(s) may increase the depreciation beyond the economical limits. Scaling can cause clogging of screens and heat exchanger resulting in an unforeseen increase in cost of maintenance and increase of interruptions in the operation of the ATE3 installation. 8 APPROACH AND SOLUTIONS The most important approach to solve or to avoid the above stipulated problems related to aquifer thermal energy storage, is found in water treatment studies and experiments. Two options under consideration at present are: 1. Addition of chemicals. 2. Microbiological and/or fluid bed methods and/or mechanical removal of solids. Both methods are applied to compensate for the transition in hydrochemical composition of the (ground)water due to heating and (to a lesser extend) due to cooling. The first option bears the insurmountable disadvantage that with each cycle more chemicals have to be added (the same groundwater is used periodically) and consequently an increase in concentration of added chemicals is unavoidable. This method risks to deteriorate the
Page 1 and 2: 4 'Hydrochemistry and energy storag
Page 4 and 5: CONTENTS AUTHORS INTRODUCTION J.W.
Page 6 and 7: 4 Corrosion 5 Some conclusions Refe
Page 8 and 9: AUTHORS 0. Andersson VIAK AB P.O. B
Page 10 and 11: INTRODUCTION J.W. Lyklema This volu
Page 12 and 13: THE INTERNATIONAL ENERGY AGENCY AND
Page 14 and 15: 3 THE IEA The International Energy
Page 16 and 17: In addition to projects in the doma
Page 18 and 19: THE RELATION BETWEEN AQUIFER THERNl
Page 20 and 21: 3 VIABILITY ATES systems contribute
Page 22 and 23: Figure 4 Temperature fluctuations o
Page 26: groundwater quality so seriously th
Page 29 and 30: developed within Annex VI (Environm
Page 31 and 32: carbonate phase, the use of a high-
Page 33 and 34: generally contain sufficient organi
Page 35 and 36: precipitation from solutions at nea
Page 37 and 38: of the water for storage. These tre
Page 39 and 40: the higher ATES temperatures. There
Page 41 and 42: One of our research objectives is t
Page 43 and 44: COUDRAIN-RIBSTEIN, A. and GOBLET, P
Page 45 and 46: SPOSITO, G, and LeVESQUE, C.S. ; 19
Page 47 and 48: saturation with respect to calcite
Page 49 and 50: system would influence the hydroche
Page 51 and 52: columns were heated from 11°C to 9
Page 53 and 54: (Table 2), clearly shows that the i
Page 55 and 56: Plate 1: CaC03 grain from first cen
Page 57 and 58: decrease in ca2+ activity, to reach
Page 59 and 60: y thermodynamic equilibrium calcula
Page 61 and 62: HOLM, T.R., EISENREICH, S.J., ROSEN
Page 63 and 64: INTRODUCTION The use of aquifers fo
Page 65 and 66: As can be seen "cloggingn has been
Page 67 and 68: specific capacity of the well and c
Page 69 and 70: the water being injected. The reaso
Page 71 and 72: Figure 5 Simplified stability diagr
Page 73 and 74: 3.4 Clogging by organic slime Clogg
Page 75 and 76:
4 CORROSION 4.1 Forms of corrosion
Page 77 and 78:
When halogens are known to be prese
Page 79 and 80:
available on the market. SOME CONCL
Page 82 and 83:
BIOGEOCHEMICAL ASPECTS OF AQUIFER T
Page 84 and 85:
In accordance with Figure 1 mangane
Page 86 and 87:
at a neutral pH is kinetically dete
Page 88 and 89:
of such biocides used against desul
Page 90 and 91:
HYDROGEOCHEMICAL TRANSPORT MODELLIN
Page 92 and 93:
The complexity of the models with a
Page 94 and 95:
The comparison shows that inclusion
Page 96 and 97:
the component O2 (Oxygen) has been
Page 98 and 99:
The results of a recent solubility
Page 100 and 101:
The neutral "exchangeable" complex
Page 102 and 103:
SrC12 elution of Delft sediment, sh
Page 104 and 105:
The saturation ratios can be used i
Page 106 and 107:
Recovered water in the long term te
Page 108 and 109:
Cumulat~ve Flow (103m3) Cumulative
Page 110 and 111:
Dissolution of silicates is in much
Page 112 and 113:
KIRKNER, D.J., and REEVES, H.; 1988
Page 114 and 115:
WATER TREATMENT AND ENVIRONMENTAL E
Page 116 and 117:
Table 1 Ove~iew of chemical treatme
Page 118 and 119:
calculated with a computer model th
Page 120:
Figure 1 Schematic representation o
Page 123 and 124:
addition shows an increase in neces
Page 125 and 126:
Table 4 summarizes the primary envi
Page 127 and 128:
wsts for this overdimensioning may
Page 129 and 130:
_? Primary circuit Figure 7 Reactor
Page 131:
Problems with iron precipitation ca
Page 134 and 135:
RESEARCH ON HYDROCHEMISTRY AND WATE
Page 136 and 137:
ANNEX XI L - -1 I Figure 1 Relation
Page 138 and 139:
stores. F. To test selected water t
Page 140 and 141:
(Fe, Ca, Mg) solid solutions. The p
Page 142 and 143:
corrosion and scaling rates under d
Page 144:
the industry. For this treatment no
Page 149 and 150:
Water nuisance. Proceedings of Tech
Page 151:
No. 36 No. 37 No. 38 Urban storm wa
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