NZ624591B2 - Paraffin wax - Google Patents
Paraffin wax Download PDFInfo
- Publication number
- NZ624591B2 NZ624591B2 NZ624591A NZ62459112A NZ624591B2 NZ 624591 B2 NZ624591 B2 NZ 624591B2 NZ 624591 A NZ624591 A NZ 624591A NZ 62459112 A NZ62459112 A NZ 62459112A NZ 624591 B2 NZ624591 B2 NZ 624591B2
- Authority
- NZ
- New Zealand
- Prior art keywords
- fischer
- paraffin wax
- tropsch
- carbon atoms
- tropsch derived
- Prior art date
Links
- 239000012188 paraffin wax Substances 0.000 title claims abstract description 104
- 125000004432 carbon atoms Chemical group C* 0.000 claims abstract description 60
- 238000002844 melting Methods 0.000 claims abstract description 18
- 238000004146 energy storage Methods 0.000 claims description 20
- 239000011232 storage material Substances 0.000 claims description 17
- 239000000463 material Substances 0.000 claims description 10
- 239000001993 wax Substances 0.000 claims description 9
- 235000019809 paraffin wax Nutrition 0.000 description 75
- 235000019271 petrolatum Nutrition 0.000 description 75
- 238000000034 method Methods 0.000 description 21
- 238000004821 distillation Methods 0.000 description 18
- 230000000052 comparative effect Effects 0.000 description 9
- 239000012071 phase Substances 0.000 description 7
- 229910052799 carbon Inorganic materials 0.000 description 6
- 238000000113 differential scanning calorimetry Methods 0.000 description 5
- 238000005984 hydrogenation reaction Methods 0.000 description 4
- 101700068145 AP25 Proteins 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 3
- 239000007788 liquid Substances 0.000 description 3
- 238000003786 synthesis reaction Methods 0.000 description 3
- 230000002194 synthesizing Effects 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 238000010309 melting process Methods 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- KWKXNDCHNDYVRT-UHFFFAOYSA-N Dodecylbenzene Chemical compound CCCCCCCCCCCCC1=CC=CC=C1 KWKXNDCHNDYVRT-UHFFFAOYSA-N 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 150000001336 alkenes Chemical class 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 239000003242 anti bacterial agent Substances 0.000 description 1
- 239000003963 antioxidant agent Substances 0.000 description 1
- 239000004566 building material Substances 0.000 description 1
- CURLTUGMZLYLDI-UHFFFAOYSA-N carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 231100000078 corrosive Toxicity 0.000 description 1
- 231100001010 corrosive Toxicity 0.000 description 1
- 239000010779 crude oil Substances 0.000 description 1
- 150000001924 cycloalkanes Chemical class 0.000 description 1
- 239000004744 fabric Substances 0.000 description 1
- 239000000945 filler Substances 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 238000005338 heat storage Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- 239000003112 inhibitor Substances 0.000 description 1
- 230000002401 inhibitory effect Effects 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- 239000002667 nucleating agent Substances 0.000 description 1
- 239000002002 slurry Substances 0.000 description 1
- 239000007790 solid phase Substances 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C9/00—Aliphatic saturated hydrocarbons
- C07C9/14—Aliphatic saturated hydrocarbons with five to fifteen carbon atoms
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C9/00—Aliphatic saturated hydrocarbons
- C07C9/22—Aliphatic saturated hydrocarbons with more than fifteen carbon atoms
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C09K5/00—Heat-transfer, heat-exchange or heat-storage materials, e.g. refrigerants; Materials for the production of heat or cold by chemical reactions other than by combustion
- C09K5/02—Materials undergoing a change of physical state when used
- C09K5/06—Materials undergoing a change of physical state when used the change of state being from liquid to solid or vice versa
- C09K5/063—Materials absorbing or liberating heat during crystallisation; Heat storage materials
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
- C10G2/00—Production of liquid hydrocarbon mixtures of undefined composition from oxides of carbon
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
- C10G2300/00—Aspects relating to hydrocarbon processing covered by groups C10G1/00 - C10G99/00
- C10G2300/20—Characteristics of the feedstock or the products
- C10G2300/30—Physical properties of feedstocks or products
- C10G2300/302—Viscosity
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
- C10G2300/00—Aspects relating to hydrocarbon processing covered by groups C10G1/00 - C10G99/00
- C10G2300/20—Characteristics of the feedstock or the products
- C10G2300/30—Physical properties of feedstocks or products
- C10G2300/308—Gravity, density, e.g. API
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
- F28D20/00—Heat storage plants or apparatus in general; Regenerative heat-exchange apparatus not covered by groups F28D17/00 or F28D19/00
- F28D20/02—Heat storage plants or apparatus in general; Regenerative heat-exchange apparatus not covered by groups F28D17/00 or F28D19/00 using latent heat
Abstract
Disclosed herein is a Fischer-Tropsch derived paraffin wax comprising paraffins having from 9 to 24 carbon atoms, which Fischer-Tropsch derived paraffin wax has a melting point in the range of 15 to 32°C, wherein the amount of Fischer-Tropsch derived paraffins having from 16 to 18 carbon atoms is at least 85 wt% based on the total amount of Fischer-Tropsch paraffins having from 14 to 20 carbon atoms or wherein the amount of Fischer-Tropsch derived paraffins having from 18 to 20 carbon atoms is at least 10 80 wt% based on the total amount of Fischer-Tropsch paraffins having from 16 to 22 carbon atoms, and wherein the Fischer-Tropsch derived paraffin wax has a kinematic viscosity at 40°C above 3.0 cSt, and a kinematic viscosity at 100°C above 0.5 cSt, and density at 40°C from 0.60 to 0.85 kg/m3. least 85 wt% based on the total amount of Fischer-Tropsch paraffins having from 14 to 20 carbon atoms or wherein the amount of Fischer-Tropsch derived paraffins having from 18 to 20 carbon atoms is at least 10 80 wt% based on the total amount of Fischer-Tropsch paraffins having from 16 to 22 carbon atoms, and wherein the Fischer-Tropsch derived paraffin wax has a kinematic viscosity at 40°C above 3.0 cSt, and a kinematic viscosity at 100°C above 0.5 cSt, and density at 40°C from 0.60 to 0.85 kg/m3.
Description
PARAFFIN WAX
The present invention provides a Fischer-Tropsch
paraffin wax and a thermal energy storage material
comprising the paraffin wax. Furthermore, the present
invention provides the use of a paraffin wax as phase
change material in thermal energy storage applications.
Paraffin wax may be obtained by various processes.
US 2,692,835 discloses a method for deriving paraffin wax
from crude oil. Also, paraffin wax may be obtained using
the so called Fischer-Tropsch process. An example of such
process is disclosed in , EP 1 498 469 and
In this specification where reference has been made
to patent specifications, other external documents, or
other sources of information, this is generally for the
purpose of providing a context for discussing the
features of the invention. Unless specifically stated
otherwise, reference to such external documents is not to
be construed as an admission that such documents, or such
sources of information, in any jurisdiction, are prior
art, or form part of the common general knowledge in the
art.
It has now surprisingly been found that specific
Fischer-Tropsch derived paraffin waxes can be
advantageously used in thermal energy storage materials.
Described herein is a Fischer-Tropsch derived
paraffin wax comprising paraffins having from 9 to 24
carbon atoms, which Fischer-Tropsch derived paraffin wax
has a melting point in the range of 15 to 40°C.
More specifically, the present invention provides a
Fischer-Tropsch derived paraffin wax comprising paraffins
having from 9 to 24 carbon atoms, which Fischer-Tropsch
derived paraffin wax has a melting point in the range of
to 32°C, wherein the amount of Fischer-Tropsch derived
paraffins having from 16 to 18 carbon atoms is at least
85 wt% based on the total amount of Fischer-Tropsch
paraffins having from 14 to 20 carbon atoms or wherein
the amount of Fischer-Tropsch derived paraffins having
from 18 to 20 carbon atoms is at least 80 wt% based on
the total amount of Fischer-Tropsch paraffins having from
16 to 22 carbon atoms.
An advantage of the present invention is that the
paraffin wax has a surprisingly high latent heat, which
high latent heat results in the reduction of the amount
of paraffin wax needed in a storage material for any
particular low-temperature thermal energy storage
application.
The Fischer-Tropsch derived paraffin wax according
to the present invention is derived from a Fischer-
Tropsch process. Fischer-Tropsch derived paraffin wax is
known in the art. By the term “Fischer-Tropsch derived”
is meant that a paraffin wax is, or is derived from, a
synthesis product of a Fischer-Tropsch process. A
Fischer-Tropsch derived paraffin wax may also be referred
to as a GTL (Gas-to-Liquids) paraffin wax. An example of
a Fischer-Tropsch process is given in , EP
1 498 469 and , the teaching of which is
incorporated by reference.
The Fischer-Tropsch derived paraffins are primarily
n-paraffins. Preferably, as referenced below, the
Fischer-Tropsch derived wax according to the present
invention comprises more than 90 wt% of n-paraffins,
preferably more than 95 wt% of n-paraffins.
According to the present invention, the Fischer-
Tropsch derived paraffin wax comprises paraffins having
from 9 to 24 carbon atoms; the Fischer-Tropsch derived
paraffin wax comprises preferably at least 70 wt%, more
preferably at least 85 wt%, more preferably at least 90
wt%, more preferably at least 95 wt%, and most preferably
at least 98 wt% of Fischer-Tropsch derived paraffins
having 9 to 24 carbon atoms based on the total amount of
Fischer-Tropsch derived paraffins, preferably based on
the amount of Fischer-Tropsch derived paraffins having
from 9 to 30 carbon atoms.
Suitably, the kinematic viscosity at 40°C (according
to ASTM D445) of the Fischer-Tropsch derived paraffin wax
according to the present invention is above 3.0 cSt,
preferably above 4.0 cSt, more preferably above 4.5 cSt.
Typically, the kinematic viscosity at 40°C (according to
ASTM D445) of the Fischer-Tropsch derived paraffin wax
according to the present invention is below 20 cSt,
preferably below 15 cSt, more preferably below 10 cSt.
Also, the kinematic viscosity at 100°C (according to
ASTM D445) of the paraffin wax is above 0.5 cSt,
preferably above 1.0 cSt, more preferably above 1.5 cSt.
Typically, the kinematic viscosity at 100°C (according to
ASTM D445) of the paraffin wax is below 15 cSt,
preferably below 10 cSt, more preferably below 5 cSt.
Further, the paraffin wax preferably has a density
at 40°C (according to ASTM D1298) from 0.60 to 0.85
kg/m , more preferably from 0.70 to 0.80 kg/m , and most
preferably from 0.75 to 0.77 kg/m .
Preferably, the density at 15°C (according to ASTM
D1298) of the paraffin wax is from 0.65 to 0.90 kg/m
more preferably from 0.70 to 0.85, more preferably from
0.75 to 0.80, and most preferably from 0.77 to 0.80
kg/m .
It is preferred that the specific heat capacity
(according to ASTM E 1269-05) of the Fischer-Tropsch
derived paraffin wax according to the present invention
is in the range of 2.10 to 2.40 J/g°C, more preferably in
the range of 2.15 to 2.40 J/g°C, more preferably in the
range of 2.15 to 2.35 J/g°C, and most preferably in the
range of 2.18 to 2.30 J/g°C. This relatively high
specific heat capacity of the Fischer-Tropsch derived wax
is of advantage as it will be able to absorb and store an
high amount of heat per degree in temperature.
It is especially preferred that the Fischer-Tropsch
derived paraffin wax according to the present invention
has a latent heat (according to ASTM E793 via Mettler
Toledo Differential Scanning Calorimetry (DSC)) between
150 and 220 J/g, preferably between 160 and 210 J/g, more
preferably between 180 and 210 J/g. As the latent heat of
the Fischer-Tropsch derived paraffin wax according the
present invention is surprisingly high, this wax may
advantageously be used as phase change materials in
thermal energy storage applications, as discussed below.
In a first embodiment the Fischer-Tropsch derived
paraffin wax described herein comprises a major amount
(i.e. > 50 wt%) of Fischer-Tropsch derived paraffins
having from 14 to 20, preferably from 16 to 18 carbon
atoms; preferably the amount of Fischer-Tropsch paraffins
having from 16 to 18 carbon atoms is at least 70 wt%,
more preferably at least 75 wt%, more preferably at least
80 wt%, more preferably at least 85 wt%, more preferably
at least 90 wt%, and most preferably at least 95 wt%
based on the total amount of Fischer-Tropsch paraffins
having from 9 to 24 carbon atoms, preferably from 14 to
carbon atoms.
Suitably, the Fischer-Tropsch derived paraffin wax
comprising Fischer-Tropsch derived paraffins having from
9 to 24 carbon atoms, preferably 14 to 20 carbon atoms,
and more preferably 16 to 18 carbon atoms, has a melting
point (according to ASTM E794) in the range of 10 to
50°C, preferably in the range of 15 to 40°C, more
preferably in the range of 15 to 32°C, more preferably in
the range of 15 to 30°C, more preferably in the range of
to 30°C, more preferably in the range of 20 to 25°C,
more preferably in the range of 20 to 24°C, and most
preferably in the range of 21 to 23°C.
Preferably, in the first embodiment of the present
invention a Fischer-Tropsch derived paraffin wax
comprising paraffins having at least 85 wt% of 16 to 18
carbon atoms, based on the total amount of Fischer-
Tropsch derived paraffins having from 9 to 24 carbon
atoms, preferably 14 to 20 carbon atoms, has a melting
point (according to ASTM E794) in the range of 21 to
23°C. Also, the Fischer-Tropsch derived paraffin wax
comprising paraffins having at least 85 wt% of 16 to 18
carbon atoms, based on the total amount of Fischer-
Tropsch derived paraffins having from 9 to 24 carbon
atoms, preferably 14 to 20 carbon atoms, has a latent
heat between 180 and 210 J/g.
In a second embodiment the Fischer-Tropsch derived
paraffin wax described herein comprises a major amount
(i.e. > 50 wt%) of Fischer-Tropsch derived paraffins
having from 16 to 22, preferably 18 to 20 carbon atoms;
preferably the amount of Fischer-Tropsch derived
paraffins having 18 to 20 carbon atoms is at least 65
wt%, more preferably at least 70 wt%, more preferably at
least 75 wt%, more preferably at least 80 wt%, more
preferably at least 85 wt%, more preferably at least 90
wt%, and most preferably at least 95 wt% based on the
total amount of Fischer-Tropsch derived paraffins having
from 9 to 24 carbon atoms, preferably 16 to 22 carbon
atoms.
Suitably, the Fischer-Tropsch derived paraffin wax
comprising Fischer-Tropsch derived paraffins having from
16 to 22, preferably 18 to 20 carbon atoms has a melting
point (according to ASTM E794), in the range of 10 to
50°C, preferably in the range of 15 to 40°C, more
preferably in the range of 15 to 32°C, more preferably in
the range of 15 to 30°C, more preferably in the range of
to 30°C, more preferably in the range of 25 to 30°C,
and most preferably in the range of 26 to 28°C.
Preferably, in the second embodiment of the present
invention a Fischer-Tropsch derived paraffin wax
comprising paraffins having at least 80 wt% of 18 to 20
carbon atoms, based on the total amount of Fischer-
Tropsch derived paraffins having from 9 to 24 carbon
atoms, preferably 16 to 22 carbon atoms, has a melting
point in the range of 26 to 28°C. Also, the Fischer-
Tropsch derived paraffin wax comprising paraffins having
at least 80 wt% of 18 to 20 carbon atoms based on the
total amount of Fischer-Tropsch derived paraffins having
from 9 to 24 carbon atoms, preferably 16 to 22 carbon
atoms, has a latent heat of between 180 and 210 J/g.
Known to those skilled in the art is that the
temperature and pressure at which the Fischer-Tropsch
process is conducted influences the degree of conversion
of synthesis gas into hydrocarbons and impacts the level
of branching of the paraffins (thus amount of
isoparaffins). Typically, the process for preparing a
Fischer-Tropsch derived wax may be carried out at a
pressure above 25 bara. Preferably, the Fischer-Tropsch
process is carried out at a pressure above 35 bara, more
preferably above 45 bara, and most preferably above 55
bara. A practical upper limit for the Fischer-Tropsch
process is 200 bara, preferably the process is carried
out at a pressure below 120 bara, more preferably below
100 bara.
The Fischer-Tropsch process is suitably a low
temperature process carried out at a temperature between
170 and 290°C, preferably at a temperature between 180
and 270°C, more preferably between 200 and 250°C.
The amount of isoparaffins is suitably less than 20
wt% based on the total amount of paraffins having from 9
to 24 carbon atoms, preferably less than 10 wt%, more
preferably less than 7 wt%, and most preferably less than
4 wt%.
Suitably, the Fischer-Tropsch derived paraffin wax
according to the present invention comprises more than
90 wt% of n-paraffins, preferably more than 95 wt% of n-
paraffins. Further, the paraffin wax may comprise iso-
paraffins, cyclo-alkanes and alkyl benzene.
The Fischer-Tropsch process for preparing the
Fischer-Tropsch derived wax according the present
invention may be a slurry Fischer-Tropsch process, an
ebullated bed process or a fixed bed Fischer-Tropsch
process, especially a multitubular fixed bed. The product
stream of the Fischer-Tropsch process is usually
separated into a water stream, a gaseous stream
comprising unconverted synthesis gas, carbon dioxide,
inert gasses and C1 to C3, and a C4+ stream.
The full Fischer-Tropsch hydrocarbonaceous product
suitably comprises a C1 to C200 fraction, preferably a C3
to C200 fraction, more preferably a C4 to C150 fraction.
Suitably, the Fischer-Tropsch derived paraffin wax
according to the present invention is obtained from the
Fischer-Tropsch hydrocarbonaceous product by
distillation. Commercially available equipment can be
used. The distillation may be carried out at atmospheric
pressure, but also reduced pressure may be used.
Preferably, the hydrocarbonaceous product stream of
the Fischer-Tropsch process, comprising a C3 to C200
fraction, preferably a C4 to C150 fraction is
hydrogenated before distillation, in order to remove
oxygenates and olefins. Further, such hydrogenated
product stream is more stable and less corrosive, making
transport and/or storage more easy.
The hydrogenation step is suitably carried out at a
temperature between 150 and 325°C, preferably between 200
and 275°C, a pressure between 5 and 120 bar, preferably
between 20 and 70 bar.
Lighter fractions of the Fischer-Tropsch product,
which suitably comprises C3 to C8 fraction, preferably C4
to C7 fraction, are separated from the Fischer-Tropsch
product by distillation thereby obtaining a first
Fischer-Tropsch product, which suitably comprises C9 to
C200 fraction.
Subsequently, a second Fischer-Tropsch product,
which suitably comprises C9 to C24 fraction, is obtained
by separation of a heavy fraction, which heavy fraction
suitably comprises C25 to C200 fraction, preferably C25
to C150 fraction, from the first Fischer-Tropsch product
by distillation. Suitably, the distillation is carried
out at a pressure of in between 50 to 70 mbara and at a
temperature of from 125 to 145°C in the top section of
the column.
After, a light fraction, which suitably comprises C9
to C13 fraction is separated from the second Fischer-
Tropsch product by distillation, thereby obtaining a
third Fischer-Tropsch product, which suitably comprises
C14 to C24 fraction. It is preferred that the
distillation is carried out at a pressure of 500 to 700
mbara and a temperature of 230 to 250°C in the bottom
stripping section of the column.
Hereafter, the Fischer-Tropsch derived paraffin wax
according to the present invention is separated from the
third Fischer-Tropsch product. Suitably, the distillation
is suitably carried out in the rectifying section in the
column at a pressure of in between 200 to 250 mbara and
at a pressure of 450 to 500 mbara in the stripping
section of the column. Also, the distillation is
preferably carried out at a temperature of from 200 to
250°C in the rectifying section of the column.
Preferably, to obtain a Fischer-Tropsch derived
paraffin wax comprising paraffins having from 14 to 20
carbon atoms, preferably 16 to 18 carbon atoms from the
third Fischer-Tropsch product the temperature in the
distillation column is between 220 to 230°C.
Preferably, to obtain a Fischer-Tropsch derived
paraffinic wax comprising paraffins having from 16 to 22
carbon atoms, preferably 18 to 20 carbon atoms from the
third Fischer-Tropsch product the temperature in the
column is between 225 to 240°C.
In another embodiment the process according to the
present invention comprises hydrogenation of smaller
fractions obtained by distillation of the full
hydrocarbonaceaous product. Hydrogenation after
distillation avoids the need to hydrogenate a large
amount of Fischer-Tropsch product. For example, the
second Fischer-Tropsch product, which suitably comprises
a C9 to C24 fraction, is hydrogenated in one or more
separate fractions before being distilled into the
Fischer-Tropsch derived paraffin wax comprising paraffins
having from 14 to 24 carbon atoms, preferably 14 to 20
carbon atoms, more preferably 16 to 18 carbon atoms or
into a Fischer-Tropsch derived paraffin wax comprising
paraffins having from 16 to 22 carbon atoms, preferably
18 to 20 carbon atoms.
In a further aspect, the present invention provides
a thermal energy storage material comprising Fischer-
Tropsch derived paraffin wax according to the present
invention. Typically, the thermal energy storage material
may be used in many areas, for instances as the thermal
insulation of lines or pipes carrying fluids, in building
materials and fabric for attires. Also, the thermal
energy storage material may be based on phase change
materials (PCM).
PCMs are compounds with a high latent heat, which
melt and solidify at certain temperature ranges, and thus
are capable of storing or releasing large amounts of
energy (heat). The transition from solid to liquid phase
(melting process) is an endothermic process, which
results in absorption of energy. The material begins to
melt upon reaching the phase change temperature. During
this melting process the temperature stays almost
constant until the melting is finished. The heat stored
during melting is the latent heat. Equally, when the
phase change process is reversed (from liquid to solid
phase), the stored latent heat is released again at a
nearly constant temperature. Furthermore, to minimize the
physical size of the heat storage device, the latent heat
should be as high as possible and the density difference
between the solid and liquid should be as small as
possible.
An advantage of the use of the paraffin wax as PCM
in thermal energy storage material is that the thermal
energy storage material has surprisingly high latent
heat. This can give a substantial reduction in the
quantity of materials required for thermal energy
storage.
Suitably, the amount of paraffin wax according to
the present invention as PCM in thermal energy storage
material is preferably at most 100 wt% and preferably at
least 90 wt%, more preferably at least 95 wt%, and most
preferably at least 98 wt% based on the total amount of
thermal storage material. Further, the thermal storage
material may - in addition to the Fischer-Tropsch derived
paraffin wax as PCM – conveniently comprise additives
such as nucleating agents, anti-oxidant or anti-bacterial
agents, corrosion inhibitors or an insoluble filler
designed to improve its stability or a solvent designed
to control its viscosity, etc.
Accordingly, the present invention provides the use
of the paraffin wax according to the present invention as
phase change material in thermal energy storage
applications.
The person skilled in the art will readily
understand that the thermal energy storage material has
the similar kinematic viscosity, density, specific heat
capacity, latent heat and melting point as the paraffin
wax according to the present invention, provided that the
amount of paraffin wax used as PCM in the thermal energy
storage material is at most 100 wt% and at least 90 wt%,
preferably at least 95 wt%, and most preferably at least
98 wt% based on the total amount of thermal energy
storage material.
In the description in this specification reference
may be made to subject matter which is not within the
scope of the appended claims. That subject matter should
be readily identifiable by a person skilled in the art
and may assist in putting into practice the invention as
defined in the appended claims.
The term “comprising” as used in this specification
and claims means “consisting at least in part of”. When
interpreting statements in this specification and claims
which include the term “comprising”, other features
besides the features prefaced by this term in each
statement can also be present. Related terms such as
“comprise”, “comprises”, and “comprised” are to be
interpreted in similar manner.
The present invention is described below with
reference to the following Examples, which are not
intended to limit the scope of the present invention in
any way.
Examples
Preparation of Fischer-Tropsch derived paraffin waxes
Two Fischer-Tropsch derived paraffin waxes (Paraffin
wax 1 and Paraffin wax 2) were obtained using a Fischer-
Tropsch process. To this end, the Fischer-Tropsch product
as obtained in Example VII using the catalyst of Example
III of WO-A-9934917 was hydrogenated at a temperature
between 200 and 275°C and at a pressure between 20 and 70
bar. The obtained Fischer-Tropsch product comprised a C4
to C150 fraction. After hydrogenation, lighter fractions
of the Fischer-Tropsch product, which comprised C4 to C7
fraction, were separated from the Fischer-Tropsch product
by distillation, thereby obtaining a first Fischer-
Tropsch product.
Subsequently, a second Fischer-Tropsch product was
obtained by separation of a heavy fraction, which heavy
fraction comprised C25 to C150 fraction, from the first
Fischer-Tropsch product by distillation at a pressure of
in between 50 to 70 mbara and at a temperature of 140°C
in the top section of the column.
After, a light fraction, which comprised C9 to C13
fraction, was separated from the second Fischer-Tropsch
product by distillation at a pressure of 500 to 700 mbara
and at a temperature of 230°C, thereby obtaining a third
Fischer-Tropsch product, which comprises a C14 to C24
fraction.
Paraffin wax 1 was separated from the third Fischer-
Tropsch product at a temperature of 221.4°C and at a
pressure of in between 200 to 250 mbara in the receiving
section of the distillation column and at a pressure of
in between 450 to 500 mbara in the stripping section of
the column. The properties of the obtained Paraffin wax 1
are listed in Table 1.
Paraffin wax 2 was separated from the third Fischer-
Tropsch product at a temperature of 227.9°C and at a
pressure of in between 200 to 250 mbara in the receiving
section of the distillation column and at a pressure of
in between 450 to 500 mbara in the stripping section of
the column. The properties of the obtained Paraffin wax 2
are listed in Table 1.
Table 1
Paraffin wax 1 Paraffin wax 2
carbon range C14-C20 C16-C22
amount of C16-C18 [wt%] 92 45
amount of C18-C20 [wt%] 45 84
melting point according 22.3 26.7
to ASTM E794 [°C]
density at 15°C 0.782 0.786
according to ASTM D1298
[kg/m ]
density at 40°C 0.769 0.770
according to ASTM D1298
[kg/ m ]
kinematic viscosity at 4.0 3.6
40°C according to ASTM
D445 [CSt]
specific heat capacity n.d. 2.27
according to ASTM E
1269-05 [J/g°C]
The sum of the amounts of [C16-C18] and [C18-C20] in
Paraffin waxes 1 and 2 is more than 100 wt% due to the fact
that both carbon ranges comprise the amount of paraffin C18.
Determination of the latent heat
Sample preparation for DSC latent heat measurements
Paraffin waxes 1 and 2 were prepared for the DSC latent
heat measurements comprising the following steps:
a) a sample of the paraffin wax was kept in an oven or
in a hot water bath until the sample was fully melted;
b) an empty pan was placed on a balance, tarred to
zero;
c) with the aid of a Pasteur pipette the homogenized
melted sample was withdrawn into the sample pan and a
weight of 0.01 mg was recorded;
d) a lid was put on the sample pan in order to close
the sample pan;
e) before analysis the total weight of the sample pan,
lid and sample was recorded.
ASTM E793 was followed for determining the latent
heat by DSC. The latent heat of Paraffin wax 1 (Example
1) and Paraffin wax 2 (Example 2) were measured with a
Mettler Toledo DSC equipped with Julabo intracooler FT100
chiller at heating and cooling rates of 10°C/min.
The melting points of the Paraffin waxes were
determined according to ASTM E794.
The latent heat and the melting points of the
Paraffin wax 1 (Example 1) and 2 (Example 2) are shown in
Table 2.
In order to show the increased latent heat of the
Fischer-Tropsch derived paraffin waxes according to the
present invention, the following commercially available
phase change materials were included as Comparative
Examples:
- Rubitherm® 20 (RT20; obtainable from DuPont, Meyrin,
Switzerland; Comparative Example A)
- Rubitherm® 27 (RT27; obtainable from DuPont, Meyrin,
Switzerland; Comparative Example B)
- Astorphase® 20B (AP20B; obtainable from International
Waxes Inc., Pennsylvania, United States; Comparative
Example C)
- Astorphase® 25 (AP25; obtainable from International
Waxes Inc., Pennsylvania, United States; Comparative
Example D)
Table 2
Comp Comp Example Comp Comp Example
Exam A Exam C 1 Exam B Exam D 2
carbon
C13-C22 n.d. C14-C20 C17-C20 n.d. C16-C22
range
melting
point 23.2 19.7 22.3 28.5 23.4 26.7
[°C]
latent
heat 113.41 110.48 197.10 131.33 127.46 207.0
[J/g]
paraffins 98.8 n.d. 93.9 99.8 n.d. 94.2
[wt%]
Discussion
The results in Table 2 show that with Fischer-Tropsch
derived Paraffin wax 1 (Example 1) a higher latent heat
was obtained compared to RT20 (Comparative Example A) and
AP20B (Comparative Example C), which both have similar
melting points as Paraffin wax 1.
Similar results were obtained with Fischer-Tropsch
derived Paraffin wax 2 (Example 2), with which a higher
latent heat was obtained compared to the latent heats of
RT27 (Comparative Example B) and AP25 (Comparative
Example D).
These observations indicate that a lower amount of the
Paraffin wax 1 and Paraffin wax 2 in thermal energy
storage materials is required to obtain the same latent
heat when compared to the amount of RT20, RT27, AP20B and
AP25.
C L A I M S
Claims (17)
1. A Fischer-Tropsch derived paraffin wax comprising paraffins having from 9 to 24 carbon atoms, which Fischer-Tropsch derived paraffin wax has a melting point in the range of 15 to 32°C, wherein the amount of 5 Fischer-Tropsch derived paraffins having from 16 to 18 carbon atoms is at least 85 wt% based on the total amount of Fischer-Tropsch paraffins having from 14 to 20 carbon atoms or wherein the amount of Fischer-Tropsch derived paraffins having from 18 to 20 carbon atoms is at least 10 80 wt% based on the total amount of Fischer-Tropsch paraffins having from 16 to 22 carbon atoms.
2. A paraffin wax according to claim 1, wherein the Fischer-Tropsch derived paraffin wax has a kinematic viscosity at 40°C above 3.0 cSt. 15
3. A paraffin wax according to claim 1 or 2, wherein the Fischer-Tropsch derived paraffin wax has a kinematic viscosity at 100°C above 0.5 cSt.
4. A paraffin wax according to any one of claims 1 to 3, wherein the Fischer-Tropsch derived paraffin wax has a 20 density at 40°C from 0.60 to 0.85 kg/m .
5. A paraffin wax according to any one of claims 1 to 4, wherein the Fischer-Tropsch derived paraffin wax has a density at 15°C from 0.65 to 0.90 kg/m
6. A paraffin wax according to any one of claims 1 to 5, 25 wherein the Fischer-Tropsch derived paraffin wax has a specific heat capacity in the range of 2.15 to 2.35 J/g°C.
7. A paraffin wax according to any one of claims 1 to 6, wherein the Fischer-Tropsch derived paraffin wax has a latent heat between 150 and 220 J/g.
8. A paraffin wax according to any one of claims 1 to 7, 5 wherein the amount of Fischer-Tropsch derived paraffins having from 16 to 18 carbon atoms is at least 90 wt% based on the total amount of Fischer-Tropsch paraffins having from 14 to 20 carbon atoms.
9. A paraffin wax according to claim 8, wherein the 10 Fischer-Tropsch derived wax has a melting point in the range of 20 to 24°C.
10. A paraffin wax according to any one of claims 1 to 7, wherein the amount of Fischer-Tropsch derived paraffins having from 18 to 20 carbon atoms is at least 85 wt% 15 based on the total amount of Fischer-Tropsch derived paraffins having from 16 to 22 carbon atoms.
11. A paraffin wax according to claim 10, wherein the Fischer-Tropsch derived paraffin wax has a melting point in the range of 25 to 30°C. 20
12. Thermal energy storage material comprising a paraffin wax according to any one of claims 1 to 11.
13. Material according to claim 12, wherein the material comprises at least 90 wt% of paraffin wax according to any one of claims 1 to 11. 25
14. Use of paraffin wax according to any one of claims 1 to 11 as phase change material in thermal energy storage applications.
15. A paraffin wax according to any one of claims 1 to 11 substantially as herein described with reference to any 30 example thereof.
16. Thermal energy storage material according to claim 12 or 13 substantially as herein described with reference to any example thereof.
17. Use according to claim 14 substantially as herein described with reference to any example thereof.
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP11187378 | 2011-11-01 | ||
EP11187378.2 | 2011-11-01 | ||
PCT/EP2012/071564 WO2013064539A1 (en) | 2011-11-01 | 2012-10-31 | Paraffin wax |
Publications (2)
Publication Number | Publication Date |
---|---|
NZ624591A NZ624591A (en) | 2016-08-26 |
NZ624591B2 true NZ624591B2 (en) | 2016-11-29 |
Family
ID=
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