WO2013000896A1 - Method and apparatus for circulating a glycol stream containing a concentration of divalent cations, and method of producing a natural gas product stream - Google Patents
Method and apparatus for circulating a glycol stream containing a concentration of divalent cations, and method of producing a natural gas product stream Download PDFInfo
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- WO2013000896A1 WO2013000896A1 PCT/EP2012/062327 EP2012062327W WO2013000896A1 WO 2013000896 A1 WO2013000896 A1 WO 2013000896A1 EP 2012062327 W EP2012062327 W EP 2012062327W WO 2013000896 A1 WO2013000896 A1 WO 2013000896A1
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- glycol
- stream
- chemical
- natural gas
- recovered
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C29/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring
- C07C29/74—Separation; Purification; Use of additives, e.g. for stabilisation
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/26—Drying gases or vapours
- B01D53/263—Drying gases or vapours by absorption
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C29/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring
- C07C29/74—Separation; Purification; Use of additives, e.g. for stabilisation
- C07C29/94—Use of additives, e.g. for stabilisation
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10L—FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G, C10K; LIQUEFIED PETROLEUM GAS; ADDING MATERIALS TO FUELS OR FIRES TO REDUCE SMOKE OR UNDESIRABLE DEPOSITS OR TO FACILITATE SOOT REMOVAL; FIRELIGHTERS
- C10L3/00—Gaseous fuels; Natural gas; Synthetic natural gas obtained by processes not covered by subclass C10G, C10K; Liquefied petroleum gas
- C10L3/06—Natural gas; Synthetic natural gas obtained by processes not covered by C10G, C10K3/02 or C10K3/04
- C10L3/10—Working-up natural gas or synthetic natural gas
- C10L3/101—Removal of contaminants
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10L—FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G, C10K; LIQUEFIED PETROLEUM GAS; ADDING MATERIALS TO FUELS OR FIRES TO REDUCE SMOKE OR UNDESIRABLE DEPOSITS OR TO FACILITATE SOOT REMOVAL; FIRELIGHTERS
- C10L3/00—Gaseous fuels; Natural gas; Synthetic natural gas obtained by processes not covered by subclass C10G, C10K; Liquefied petroleum gas
- C10L3/06—Natural gas; Synthetic natural gas obtained by processes not covered by C10G, C10K3/02 or C10K3/04
- C10L3/10—Working-up natural gas or synthetic natural gas
- C10L3/101—Removal of contaminants
- C10L3/102—Removal of contaminants of acid contaminants
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10L—FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G, C10K; LIQUEFIED PETROLEUM GAS; ADDING MATERIALS TO FUELS OR FIRES TO REDUCE SMOKE OR UNDESIRABLE DEPOSITS OR TO FACILITATE SOOT REMOVAL; FIRELIGHTERS
- C10L3/00—Gaseous fuels; Natural gas; Synthetic natural gas obtained by processes not covered by subclass C10G, C10K; Liquefied petroleum gas
- C10L3/06—Natural gas; Synthetic natural gas obtained by processes not covered by C10G, C10K3/02 or C10K3/04
- C10L3/10—Working-up natural gas or synthetic natural gas
- C10L3/107—Limiting or prohibiting hydrate formation
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2252/00—Absorbents, i.e. solvents and liquid materials for gas absorption
- B01D2252/20—Organic absorbents
- B01D2252/202—Alcohols or their derivatives
- B01D2252/2023—Glycols, diols or their derivatives
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/14—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by absorption
- B01D53/1425—Regeneration of liquid absorbents
Definitions
- the present invention relates to a method and
- the present invention relates to a method of producing a natural gas product stream.
- Recirculation of glycol is often used in a context of transportation of a mixture of hydrocarbons comprising natural gas, water, and dissolved salts in production pipelines from an off-shore located (mineral) hydrocarbon reservoir to a land based or floating top-side facilities for processing the mixture to recover the desired
- lean glycol relatively low water content glycol
- the glycol comprising natural gas, water, and dissolved salts, and then extract the glycol as so-called rich glycol from the process fluid at the top-side facilities.
- the rich glycol has a higher water content than the lean glycol.
- the glycol often selected for this purpose is mono ethylene glycol (MEG) , in which case the lean glycol is referred to as lean MEG and the rich glycol is referred to as rich MEG.
- MEG mono ethylene glycol
- the glycol stream should be recirculated.
- rich MEG is typically regenerated to form lean MEG and then reused as hydrate inhibiting agent in the production lines.
- Rich MEG usually contains remains of the hydrocarbons, high water levels, corrosion products, production chemicals and a mixture of dissolved mineral salts .
- divalent cations notably Ca ⁇ +
- solubility of salts formed from such divalent cations is relatively low compared to mono-valent salts such as NaCl or KC1.
- WO 2011/028131 discloses a device and method for recovering MEG after use as hydrate inhibiting agent in production lines of gas- and oil fields.
- the process fluid from the production lines is subjected to a
- Divalent cations are precipitated from the aqueous fraction of rich MEG by injecting chemicals, such as NaOH or K2CO3 or others, to achieve sufficient alkalinity and heating of the aqueous fraction.
- Solid particles are removed from the aqueous fraction of rich MEG by purging the liquid with a purging gas and skim off the foam forming on the surface of the aqueous fraction. Subsequently, the MEG is regenerated whereby a fraction of lean MEG is recovered.
- a drawback of the method disclosed in WO 2011/028131 is that it requires a relatively high amount of
- the present invention provides a method of circulating a glycol stream containing a concentration of divalent cations, comprising
- the stream of recovered glycol comprises a least a first portion and a second portion, wherein the first portion of the recovered glycol has passed through the chemical divalent cation removal step whereby divalent cations are removed from a first part of the glycol which passes through said chemical divalent cation removal - - step, and wherein the second portion of said recovered glycol has not passed through the chemical divalent cation removal step.
- the present invention provides an apparatus for circulating a glycol stream containing a concentration of divalent cations, comprising:
- an inlet separation system at the downstream location, arranged to receive the process stream with the glycol- containing stream and to separate the process stream with the glycol-containing stream into at least an aqueous phase and a natural gas phase, said aqueous phase
- glycol recovery system comprising an recovery system inlet in fluid communication with the inlet separation system, said glycol recovery system arranged to receive the aqueous phase via the recovery system inlet and to recover glycol from the aqueous phase to form a stream of recovered glycol, said recovery system further comprising a recovery system outlet for discharging the stream of recovered glycol, wherein said glycol recovery system comprises a chemical divalent cation removal unit
- glycol injection line fluidly connecting the recovery system outlet with the injection point, said glycol injection line arranged to transport the stream of recovered glycol from the glycol recovery system to the injection point;
- glycol recovery system further comprises a second path between the recovery system inlet and the recovery system outlet, which second path bypasses the chemical divalent cation removal unit so that the
- stream of recovered glycol comprises a least a first portion and a second portion, wherein the first portion of the recovered glycol has passed through the chemical divalent cation removal unit whereby divalent cations are removed from a first part of the glycol which passes through said chemical divalent cation removal unit, and wherein the second portion of said recovered glycol has not passed through the chemical divalent cation removal unit .
- the present invention provides a method of producing a natural gas product stream, comprising:
- said recovering of glycol from the aqueous phase comprises a chemical divalent cation removal step and wherein the stream of recovered glycol comprises a least a first portion and a second portion, wherein the first portion of the recovered glycol has passed through the chemical divalent cation removal step whereby divalent cations are removed from a first part of the glycol which passes through said chemical divalent cation removal step, and wherein the second portion of said recovered glycol has not passed through the chemical divalent cation removal step circulating a glycol stream
- Figure 1 schematically illustrates a method and apparatus for circulating a glycol stream, involving a glycol recovery system, in a method and apparatus for producing a natural gas product stream;
- Figure 2 schematically illustrates a reference case for the glycol recovery system not according to the invention
- Figures 3 to 7 each schematically illustrates various embodiments of a glycol recovery system that can be employed in embodiments of the invention.
- the present disclosure relates to circulation of a glycol stream involving injecting of a glycol containing stream into a pipeline at an upstream location through which pipeline the glycol containing stream is conveyed to a downstream location together with a process stream, and recovering of the glycol at the downstream location and transporting the stream of recovered glycol back to the upstream location for reinjection.
- only a first portion of the recovered glycol has passed through a chemical divalent cation removal step whereby divalent cations are chemically removed from only the part of the glycol which passes through said chemical divalent cation removal step.
- a second portion of said recovered glycol has not passed through the, or preferably any, chemical divalent cation removal step since its most recent injection into the pipeline.
- the chemical consumption in the divalent cation removal step is lower and a smaller amount of chemicals is required to be injected.
- the equipment associated with performing the chemical divalent cation removal step can be kept smaller.
- the chemical divalent cation removal step may be a wet chemical divalent cation removal step. Such a wet chemical divalent cation removal step allows for
- the divalent cation load in the pipeline can stay below a pre-selected value.
- the relative amount of glycol in the first portion compared to the total amount of recovered glycol is selected such that the concentration of divalent cations arriving in the
- pipeline at the downstream location is maintained below a pre-selected value. This can be done typically by controlling a split ratio of the flow rate of the first part of the glycol that is passed to the chemical divalent cation removal step and the total flow rate of glycol passing through the downstream location into stream of recovered glycol. - -
- the term "recovered glycol” is used for lean glycol that has passed through the glycol recovery system once after for the last time having been received at the downstream location from the pipeline and has not yet been reinjected in the pipeline at the upstream location since it was for the last time received at the downstream location from the pipeline.
- the recovered glycol stream also comprises freshly added glycol from another glycol source, such glycol is not considered to be recovered glycol .
- the chemical divalent cation removal unit typically comprises a chemical component injecting system fluidly connected to a source of a chemical component, which chemical component is reactable with the divalent
- divalent cations examples include Fe ⁇ + , Ca ⁇ -1- , Mg2+, Ba2+, Sr2+. Others exist in addition to these examples.
- Ca ⁇ + is considered to be of most pertinence in the context of the present invention, because it is usually the most abundant divalent cation in formation water .
- a pipeline 10 extends from an upstream location A to a downstream location B, for conveying a process stream 11 containing natural gas from the upstream location A to the downstream location B.
- the pipeline has an upstream end 12 at the upstream location A, and a downstream end 14 at the downstream location B.
- the injection point 20 is schematically indicated in the pipeline 10 between its upstream end 12 and its downstream end 14, but this is not a requirement of the invention. It may be located upstream of the upstream end 12, such as in a connection
- the upstream location A is often situated off-shore, but this is not a main requirement of the invention.
- glycol injection is desired when conveying process streams containing natural gas and water from an off-shore location through an underwater pipeline.
- the downstream location B can be on shore, as will often be the case, or off-shore on a hydrocarbon processing platform such as on a floating production, storage and offloading unit.
- a transit zone C Between the upstream location A and the downstream location B is typically a transit zone C, in which essentially the process stream 11 is transported from the upstream location A to the downstream location B.
- a stream of recovered glycol 50 is transported through the transit zone C from the downstream location B to the upstream location A.
- An inlet separation system 30 is provided at the downstream location B.
- the pipeline 10 is connected to the inlet separator 30 via its downstream end 14.
- the inlet separation system 30 is arranged to receive the process stream with the injected glycol-containing - - stream, and to separate the process stream with the glycol-containing stream into at least an aqueous phase 40 and a natural gas phase 60.
- the aqueous phase 40 contains at least a part of the glycol originating from the glycol containing stream.
- the natural gas phase does not have to consist purely of natural gas, but it
- the inlet separation system 30 of Figure 1 comprises a high-pressure separator 31 in the form of a three-phase separator, and a low-pressure separator 37.
- the high- pressure separator 31 is fluidly connected to a
- hydrocarbon condensate discharge line 32 a high-pressure aqueous phase discharge line 33, and a high-pressure gas phase discharge line 34.
- the low-pressure separator is connected to the high-pressure aqueous phase discharge line 33 via respectively an optional heater 35 and a pressure reduction valve 36. In the low-pressure
- the high-pressure aqueous phase 33 is separated into an aqueous phase and a low pressure gas phase, and low pressure condensate phase, each of which being discharged from the low-pressure separator 37.
- the low-pressure separator is connected to a low-pressure condensate phase discharge line 38, a low- pressure gas phase discharge line 39 and a low pressure aqueous phase discharge line 40.
- the aqueous phase 40 from the inlet separation system 30 is drawn from the low-pressure separator 37.
- One or both of the high-pressure gas phase discharge line 34 and the low-pressure gas phase discharge line 39 may be connected to a natural gas phase line 60 to covey the - - natural gas phase to a natural gas treatment system 200 as shown by dotted lines.
- Pressure adjusting equipment for instance selected from a pressure-reduction valve, an expansion turbine, a compressor, may be inserted as needed to adjust the pressure of the high-pressure gas phase and/or the low-pressure gas phase to obtain a target natural gas treatment pressure.
- the high-pressure gas phase discharge line 34 connects to the natural gas phase line 60 as this makes optimal use of the already available pressure in the pipeline 10.
- the high-pressure separator 37 may typically be operated at a pressure of between 40 and 100 bara, such as about 70 bara, and the low-pressure separator may typically be operated at between 10 and 40 bara, such as about 25 bara.
- Such pressures are examples, and not limiting on the invention.
- the glycol recovery system 100 comprises a recovery system inlet 105 in fluid
- the glycol recovery system 100 is arranged to receive the aqueous phase 40 via the recovery system inlet 105, and further to recover glycol from the aqueous phase 40 to form a stream of recovered glycol 50.
- the recovery system 100 further comprises a recovery system outlet
- the glycol recovery system 100 comprises a chemical divalent cation removal unit 130 arranged in a first path 110 extending through the divalent cation removal unit 130 from the recovery system inlet 105 to the recovery system outlet 107. Possible arrangements of the divalent cation removal unit 130 within the glycol recovery system 100 will be discussed in more detail below. - -
- the apparatus described so far with reference to Figure 1 can be employed to circulate a glycol stream from a starting point at the upstream location A via the transit zone C to the downstream location B where it arrives as a rich glycol stream; through a regeneration process wherein the rich glycol stream is regenerated to form a lean glycol stream; and in the form of the lean glycol stream back from the downstream location B via the transit zone C to the upstream location A to the starting point.
- Glycol storage means may be provided in the glycol circulation loop as desired.
- a rich glycol storage tank may be provided to temporarily store the aqueous phase 40 in the downstream location B upstream of the glycol recovery system 100.
- a lean glycol storage tank may be provided to temporarily store the recovered glycol stream 50 at the downstream location B prior to conveying it to the upstream location A.
- the process stream 11 containing natural gas is conveyed from the hydrocarbon production well 5 via connection 15 through the pipeline 10 from the upstream location A to the downstream location B.
- the glycol containing stream is injected into the pipeline 10 at the injection point 20, and conveyed with the process stream 11 through the pipeline 10 to the downstream location B.
- the process stream 11 with the glycol-containing stream is separated into at least the aqueous phase 40 and the natural gas phase 60.
- the aqueous phase 40 contains at least a part of the glycol originating from the glycol containing stream.
- the natural gas phase 60 contains at least a part of the natural gas from the process stream 11. - -
- Glycol is recovered from the aqueous phase 40 to form a stream of recovered glycol 50, wherein the recovering of glycol from the aqueous phase 40 comprises a chemical divalent cation removal step executed in the chemical divalent cation removal unit 130.
- the recovered glycol 50 is conveyed in a glycol injection line that fluidly connects the recovery system outlet 107 at the downstream location B with the
- the glycol injection line is arranged to transport the stream of recovered glycol 50 from the glycol recovery system 100 to the injection point 20.
- the stream of recovered glycol 50 is transported to the injection point 20 and added to the glycol containing stream being injected.
- a natural gas treatment system 200 is provided, in fluid communication with the inlet separation system 100. This natural gas treatment system 200 is arranged to receive the natural gas phase 60 via a treatment system inlet 205, and to further treat the incoming natural gas phase 60 to form a natural gas product stream 70.
- the natural gas treatment system 200 thus further comprises a treatment system outlet 207, for discharging the natural gas product stream 70.
- the natural gas treatment system 200 may comprise one or more of gas treatment units in a natural gas treatment path 202 extending between the treatment system inlet 205 and the treating system outlet 207 as selected from the group consisting of: dew pointing unit, dehydration unit, acid - - gas removal unit, mercury removal unit, natural gas liquids extraction unit, cooling unit, liquefying unit, nitrogen removal unit, helium removal unit.
- Figs. 2 to 7 there are shown a few examples of glycol recovery systems which could be used as the glycol recovery system 100 in Fig. 1.
- All systems comprise a chemical divalent cation removal unit 130 arranged in a first path 110 between the recovery system inlet 105 and the recovery system outlet 107.
- This chemical divalent cation removal unit 130 comprises a chemical component injecting system 132 that is fluidly connected to a source 133 of a chemical component. The chemical component is reactable with the divalent
- the chemical component After injecting the chemical component into a first part of the glycol which is subject to the chemical divalent cation removal step 130, it can react with at least a portion of the divalent cations present in the first part of the glycol.
- the reacted divalent cations may be removed from the chemical divalent cation removal unit 130 in the form of a slurry stream 136.
- the chemical divalent cation removal unit 130 may comprise means, preferably a glycol centrifuge (not shown) , to separate the slurry from a liquid bulk 138.
- the liquid bulk 138 is also discharged from the chemical divalent cation removal unit 130, which contains the aqueous phase including glycol, from which the slurry stream 136 has been removed.
- the liquid bulk 138 is then passed further through the glycol recovery system 100 towards the recovery system outlet
- the slurry stream 136 may be pumped out to a further treatment and/or disposal.
- the chemical component is an alkaline component.
- the glycol recovery system 100 preferably comprises an acid injecting system 162 to inject an acid into the recovered glycol 50 to neutralize the alkalinity caused by the injection of the alkaline component.
- the acid injecting system 162 is fluidly connected to an acid source 163.
- a suitable acid for this purpose is HC1, but other acids may be employed at choice .
- the alkaline component may for instance be selected from the group consisting of hydroxide alkalines (for example potassium hydroxide and sodium hydroxide) and carbonate alkalines (for example potassium carbonate) and combinations thereof.
- a hydroxide may be selected if the aqueous phase 40 if there is enough CO2 in the chemical divalent cation removal unit 130 (typically brought in via the aqueous phase 40) for the hydroxide to react with and form carbonate.
- a carbonate alkaline may be preferred if there are insufficient amounts of CO2 in the chemical divalent cation removal unit 130 to form carbonate .
- the alkaline component is injected at an alkaline injection rate sufficient to bring the pH inside the chemical cation removal unit 130 to a sufficiently high value for divalent cations to form precipitates.
- Figure 2 relates to a reference case, which is not according to the invention.
- the chemical divalent cation removal unit 130 it comprises a
- regenerator 140 regenerator 140 and an optional reclamation unit 150.
- the regenerator 140 is arranged to separate water from the glycol in a regeneration step. Such a
- regenerator 140 may be arranged within the glycol
- a central element in such a regenerator 140 is typically a glycol distillation column. Water boils off from the glycol- containing aqueous phase 40, and water vapour with very low concentration of glycol (e.g. less than 1000 ppm by weight) is discharged as overhead stream from the glycol distillation column. Said water vapour is typically condensed in a reflux condenser and fed to a reflux drum.
- Any non-condensed vapour 142 may be routed to a flare or disposed of in any other suitable way.
- Part of the condensed liquid is fed back to the top of the glycol distillation column as reflux stream (typically assisted by a reflux pump) ; the remainder is drawn from the regenerator 140 as produced water stream 144 to be further treated.
- a small hydrocarbon condensate stream 146 may also be drawn from the reflux drum and disposed of.
- Lean glycol is discharged from the bottom of the glycol distillation column, and part of it is reboiled and sent back to the glycol distillation column as stripping vapour.
- the remainder of the lean glycol may be discharged from the regenerator 140 in the form of - - regenerated glycol stream 148.
- the optional reclamation unit 150 is typically a distillative reclamation unit, and serves to perform a reclamation step wherein to reclaim glycol from salts by distillation rather than chemically. Herewith, also monovalent and high solubility salts are removed from the glycol .
- the glycol is flash-separated in a flash separator, by reducing the pressure preferably to a sub-atmospheric pressure.
- the salt-free lean glycol is flashed off and discharged from the flash separator as overhead stream, which is
- the stream of salt-free lean glycol is discharged from the reclamation unit via line 158.
- a mixture of glycol with crystallized salts is drawn from the bottom of the flash separator. After removing the crystallized salts from this mixture (typically using centrifuge techniques), the glycol is heated and recycled back to the flash separator either as a separate stream or together with the glycol feed stream to the flash separator.
- a recycle pump may be employed to assist the recycling. Salts are removed from the process via salt line 152 for further treatment and disposal.
- An antifoam agent may be used upstream of the
- regenerator 140 and/or the optional reclamation unit 150 to prevent foaming in these. It is expected that such - - agent may only be needed occasionally during specific upset conditions.
- the optional reclamation unit 150 may be disposed in the glycol recovery system 100 between the recovery system inlet 105 and the regenerator 140, or as shown in the embodiment of Figure 2, between the
- the optional reclamation unit 150 is disposed in the glycol recovery system 100 between the recovery system inlet 105 and the regenerator 140.
- the optional reclamation unit 150 can be arranged such that all of the recovered glycol in the recovered glycol stream has passed through the reclamation unit 150 similar as with the regenerator 140.
- the optional reclamation unit 150 is preferably provided between the chemical divalent cation removal unit 130 and the recovery system outlet 107 as shown in the embodiment of Figure 2, such that the reclamation step is downstream of the chemical divalent cation removal step.
- the reclamation unit 150 by its distillative nature also removes a large part of the alkalinity from the glycol, so that by positioning the - - reclamation unit 150 within the glycol recovery system 100 downstream of the chemical divalent cation removal step and/or unit 130, remnants of alkaline components that have been added are removed with the salts.
- an additional advantage is that the chemical consumption in the form of acid consumption is advantageously reduced at the same time.
- reclamation unit 150 because there is a reclamation unit bypass line 155 available.
- injection system 162 may be provided as described above with reference to Figure 2.
- the chemical divalent cation removal unit 130 is provided, together with the chemical component injecting system 132 and source 133.
- an essential difference between the embodiments according to the invention and the reference case resides in the presence of a second path extending between the recovery system inlet 105 and the recovery system outlet 107, which second path bypasses the chemical divalent - - cation removal unit 130.
- the second path follows a salt removal bypass line 125.
- the first path does not go through this salt removal bypass line 125, but follows a desalting slipstream 111, instead, which leads through at least the chemical divalent cation removal unit 130.
- the stream of recovered glycol 50 comprises a least a first portion of recovered glycol that has passed through the chemical divalent cation removal unit 130, and a second portion of the recovered glycol that has not passed through the chemical divalent cation removal unit 130.
- the second portion which has taken the salt removal bypass line 125, has not passed through any chemical salt removal apparatus and/or step.
- the chemical divalent cation removal unit 130 Only a first part of the glycol is split off and passed through the chemical divalent cation removal unit 130 in the form of the desalting slipstream 111. As a result, the consumption rate of chemicals in the chemical divalent cation removal unit 130 is lower and much less chemical flow is needed through the chemical component injection system 132. Moreover, the chemical cation removal unit 130 and optionally any other equipment associated with the chemical cation removal step such as any supply source for the chemical component (s) used in the chemical divalent cation removal unit 130, can be smaller due to the lower flow rates.
- the splitting off of the first part of the glycol is controlled by a controller 108.
- the controller 108 is arranged to control the relative flow rate of the first part of the glycol that is passed to the chemical divalent cation removal unit 130, compared to the total flow rate of glycol passing - - through the glycol recovery system (e.g. in line 40) into the stream of recovered glycol 50.
- the controller may cooperate with a flow control valve, such as the flow control valve 109 arranged in the desalting slipstream line 111 to control the relative flow rate of the first part of the glycol that is passed to the chemical divalent cation removal unit 130.
- the relative flow rate may be controlled in response to the concentration of divalent cations arriving in the pipeline 10 at the downstream location B.
- the relative flow rate of glycol in the first portion compared to the total flow rate of recovered glycol may be controlled such that the concentration of divalent cations arriving in the pipeline 10 at the downstream location B is maintained at a selected value below a pre-selected value.
- the pre-selected value can be pre-selected such as to prevent scaling in the regenerator 140. Generally, scaling is prevented if the concentration of each
- divalent cation in the rich glycol that is subjected to the regenerator is below its saturation level at the operating conditions experienced in the regenerator 140 (including pH value, pressure, temperature, etc) . It may be determined in any way suitable for the person skilled in the art, including empirically or by
- the saturation level itself may be influenced by controlling the pH value of the aqueous phase 40.
- the pH - - value of the aqueous phase 40 may be controlled by controlling the injection rate of the optional acid in response to the pH value.
- a target pH value is set low enough to achieve desired saturation level.
- the target pH value is in a range of from 5.5 to 6.9.
- An injection rate controller may thus be provided, coupled to a pH sensor which is capable of producing a pH signal indicative of the pH value of the aqueous phase 40 and coupled to a flow rate control valve within the acid injection system 162 (not shown) .
- the pH value may be established from a signal generated by a suitable sensor in any suitable stream, but preferred is anywhere downstream of the pipeline 10 but upstream of the regenerator 140.
- regenerator 140 is preferably controlled.
- a more direct prevention of scaling can be achieved if a regenerator 140 is provided by controlling the relative flow rate of glycol in the first portion
- the concentration of divalent cations fed to the regenerator 140 (and/or the regeneration step) is maintained at a selected value below a pre-selected maximum value.
- controller 108 and its operation as described with reference to Figure 3 can also be applied in other embodiments, including those shown in Figs. 4 to 7.
- regenerator 140 is arranged such that both the first and second portions of the stream of recovered glycol 50 at the glycol recovery - - system outlet 107 have passed through the regenerator 140 and/or the regeneration step.
- the optional reclamation unit 150 may be in one or both of said first path and said second path.
- said reclamation step such as e.g. in Figs. 3 and 4.
- the optional reclamation unit 150 is provided in the first path but not the second path.
- the first portion of the recovered glycol 50 (which is the portion that has passed through the chemical divalent cation removal unit and/or step) has also passed through the optional reclamation unit 150 and/or step while the second portion of the recovered glycol stream 50 (which has not passed through the chemical divalent cation removal unit and/or step) has not passed through the optional reclamation unit 150 and/or step.
- This allows for maximum removal of the alkaline components that have been added in the chemical divalent removal unit 130, while at the same time allowing for minimizing the required size of the optional reclamation unit 150.
- the glycol can pass through the reclamation unit 150 or bypass it independently of whether it has passed through the chemical divalent cation removal unit 130.
- the regenerator is arranged within the recovery system 100 between the recovery system inlet 105 and the chemical divalent cation removal unit 130, such that the chemical divalent cation removal step is downstream of the regeneration step in any single pass through the glycol recovery system 100.
- the flow rate that needs to pass through the chemical divalent cation removal unit 130 is even lower, because the stream that will be subjected to the chemical divalent cation removal step is based on regenerated glycol taken from the regenerated glycol stream 148, which has a relatively low water content compared to the aqueous phase containing rich glycol.
- the associated equipment can be even smaller.
- the likelihood of mercury contamination in the precipitated solids is smaller if the chemical divalent cation removal step is performed downstream of the regeneration step within the glycol recovery system. This facilitates the further disposal of the precipitated solids .
- Table I flow rate of Ca( 2+ ), KOH, and HC1, in kg/hr in various streams.
- regenerator 140 does not affect the Ca flow.
- the value of 27.5% was selected to achieve that the calcium flow rate in the pipeline 10 was maintained at a select value of 109 kg/hr.
- the invention also serves to reduce the consumption of acid (in cases where optional acid injection is applied) and to reduce the acid
- the natural gas phase 60 is further treated thereby producing the natural gas product stream 70.
- the stream of recovered glycol 50 is transported to the injection point 20 and added to the glycol containing stream being injected.
- the further treating of the natural gas phase 60 may comprise subjecting at least a fraction of the natural gas phase 60 to one or more gas treatment steps selected - - from the group consisting of: dew pointing, dehydration, acid gas removal, mercury removal, extraction of natural gas liquids, cooling, liquefying, nitrogen removal, helium removal.
- the natural gas product stream can be produced in the form of a liquefied natural gas stream, which may be stored at cryogenic temperature (typically below about -160 °C at near atmospheric conditions of 1.2 bara or less) and shipped in bulk form by tankers.
- cryogenic temperature typically below about -160 °C at near atmospheric conditions of 1.2 bara or less
- the natural gas treatment system 200 together with the glycol recovery system and optionally together with the inlet separation system may all be provided on a single floating platform for instance on a floating vessel comprising one or more storage tanks.
- the one or more storage tanks may be provided downstream of the natural gas treatment system 200, and arranged to receive and store the natural gas product stream until it can be offloaded .
- downstream location B is off-shore, since off-shore space for processing equipment is relatively scarce and comes at a high added cost.
Abstract
Description
Claims
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB1320793.1A GB2541151A (en) | 2011-06-27 | 2012-06-26 | Method and apparatus for circulating a glycol stream containing a concentration or divalent cations, and method of producing a natural gas product stream |
AU2012277884A AU2012277884B2 (en) | 2011-06-27 | 2012-06-26 | Method and apparatus for circulating a glycol stream containing a concentration of divalent cations, and method of producing a natural gas product stream |
KR1020147001377A KR101977426B1 (en) | 2011-06-27 | 2012-06-26 | Method and apparatus for circulating a glycol stream containing a concentration of divalent cations, and method of producing a natural gas product stream |
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP11171421.8 | 2011-06-27 | ||
EP11171421 | 2011-06-27 | ||
EP11171422 | 2011-06-27 | ||
EP11171422.6 | 2011-06-27 |
Publications (1)
Publication Number | Publication Date |
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WO2013000896A1 true WO2013000896A1 (en) | 2013-01-03 |
Family
ID=46466455
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/EP2012/062327 WO2013000896A1 (en) | 2011-06-27 | 2012-06-26 | Method and apparatus for circulating a glycol stream containing a concentration of divalent cations, and method of producing a natural gas product stream |
Country Status (4)
Country | Link |
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KR (1) | KR101977426B1 (en) |
AU (1) | AU2012277884B2 (en) |
GB (1) | GB2541151A (en) |
WO (1) | WO2013000896A1 (en) |
Cited By (2)
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---|---|---|---|---|
WO2016053586A1 (en) * | 2014-09-29 | 2016-04-07 | Cameron Solutions, Inc. | System and method for ph control of lean meg product from meg regeneration and reclamation packages |
WO2018115442A1 (en) * | 2016-12-23 | 2018-06-28 | Nov Process & Flow Technologies As | Hydrate inhibitor recovery system |
Citations (4)
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US20050072663A1 (en) * | 2002-10-28 | 2005-04-07 | Geraldine Laborie | Method of regenerating an aqueous glycol solution containing salts |
WO2007073204A1 (en) * | 2005-12-21 | 2007-06-28 | Statoilhydro Asa | Process and plant for the regeneration of glycol |
FR2899822A1 (en) * | 2006-04-12 | 2007-10-19 | Inst Francais Du Petrole | Regenerating hydration inhibitor solution, for use in transporting natural gas comprises distilling and contacting with ion-fixing solid to reduce water and ion contents |
WO2011028131A1 (en) | 2009-09-02 | 2011-03-10 | Aker Process Systems As | Device and method for recovering meg |
Family Cites Families (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2711650B1 (en) * | 1993-10-29 | 1995-12-01 | Elf Aquitaine | Process for the purification of a glycolic solution based on one or more glycols and containing, in addition, water and, as impurities, salts and hydrocarbons. |
FR2858247B1 (en) * | 2003-07-30 | 2005-09-09 | Inst Francais Du Petrole | PROCESS FOR TREATING GAS WITH A FILTERED GLYCOL SOLUTION |
-
2012
- 2012-06-26 AU AU2012277884A patent/AU2012277884B2/en not_active Ceased
- 2012-06-26 GB GB1320793.1A patent/GB2541151A/en not_active Withdrawn
- 2012-06-26 WO PCT/EP2012/062327 patent/WO2013000896A1/en active Application Filing
- 2012-06-26 KR KR1020147001377A patent/KR101977426B1/en active IP Right Grant
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20050072663A1 (en) * | 2002-10-28 | 2005-04-07 | Geraldine Laborie | Method of regenerating an aqueous glycol solution containing salts |
WO2007073204A1 (en) * | 2005-12-21 | 2007-06-28 | Statoilhydro Asa | Process and plant for the regeneration of glycol |
FR2899822A1 (en) * | 2006-04-12 | 2007-10-19 | Inst Francais Du Petrole | Regenerating hydration inhibitor solution, for use in transporting natural gas comprises distilling and contacting with ion-fixing solid to reduce water and ion contents |
WO2011028131A1 (en) | 2009-09-02 | 2011-03-10 | Aker Process Systems As | Device and method for recovering meg |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2016053586A1 (en) * | 2014-09-29 | 2016-04-07 | Cameron Solutions, Inc. | System and method for ph control of lean meg product from meg regeneration and reclamation packages |
US9757708B2 (en) | 2014-09-29 | 2017-09-12 | Cameron Solutions, Inc. | System and method for pH control of lean MEG product from MEG regeneration and reclamation packages |
US10232340B2 (en) | 2014-09-29 | 2019-03-19 | Cameron Solutions, Inc. | System and method for pH control of lean MEG product from MEG regeneration and reclamation packages |
WO2018115442A1 (en) * | 2016-12-23 | 2018-06-28 | Nov Process & Flow Technologies As | Hydrate inhibitor recovery system |
Also Published As
Publication number | Publication date |
---|---|
KR101977426B1 (en) | 2019-05-10 |
KR20140041764A (en) | 2014-04-04 |
GB2541151A (en) | 2017-02-15 |
AU2012277884B2 (en) | 2015-02-12 |
AU2012277884A1 (en) | 2013-02-28 |
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