CN110835567A - Method for lowering freezing point of LNG (liquefied Natural gas) - Google Patents

Method for lowering freezing point of LNG (liquefied Natural gas) Download PDF

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Publication number
CN110835567A
CN110835567A CN201911083430.3A CN201911083430A CN110835567A CN 110835567 A CN110835567 A CN 110835567A CN 201911083430 A CN201911083430 A CN 201911083430A CN 110835567 A CN110835567 A CN 110835567A
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CN
China
Prior art keywords
lng
parts
freezing point
short
chain hydrocarbon
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Pending
Application number
CN201911083430.3A
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Chinese (zh)
Inventor
赵延兴
公茂琼
王宪
王峰渊
李振明
陈盼盼
于国鹏
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Technical Institute of Physics and Chemistry of CAS
Sinopec Engineering Inc
State Grid Corp of China SGCC
State Grid Zhejiang Electric Power Co Ltd
China Electric Power Research Institute Co Ltd CEPRI
Original Assignee
Technical Institute of Physics and Chemistry of CAS
Sinopec Engineering Inc
State Grid Corp of China SGCC
State Grid Zhejiang Electric Power Co Ltd
China Electric Power Research Institute Co Ltd CEPRI
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Application filed by Technical Institute of Physics and Chemistry of CAS, Sinopec Engineering Inc, State Grid Corp of China SGCC, State Grid Zhejiang Electric Power Co Ltd, China Electric Power Research Institute Co Ltd CEPRI filed Critical Technical Institute of Physics and Chemistry of CAS
Priority to CN201911083430.3A priority Critical patent/CN110835567A/en
Publication of CN110835567A publication Critical patent/CN110835567A/en
Pending legal-status Critical Current

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    • 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
    • C10L3/12—Liquefied petroleum gas
    • 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
    • C10L10/00—Use of additives to fuels or fires for particular purposes
    • 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
    • C10L3/003—Additives for gaseous fuels

Abstract

According to the method for lowering the freezing point of the LNG, the short-chain hydrocarbon compound is added into the conventional LNG, the conventional LNG mainly comprises over 95 percent of methane and a small amount of short-chain alkane or olefin components, and the short-chain alkane or olefin components such as ethane, propane, n-butane, isobutane, n-pentane, ethylene, propylene and the like have lower freezing point and higher combustion heat value, and the short-chain hydrocarbon compound is added into the conventional LNG, so that the freezing point of the LNG can be obviously lowered, and the combustion heat value of the LNG is not greatly influenced.

Description

Method for lowering freezing point of LNG (liquefied Natural gas)
Technical Field
The invention relates to the technical field of natural gas liquefaction, in particular to a method for reducing the freezing point of LNG.
Background
The energy is an important material basis of national economy, and compared with traditional energy sources such as coal, petroleum and the like, natural gas has the advantages of high heat value, safe use, cleanness and the like, and becomes an important component part in energy structures of various countries in the world. Liquefied Natural Gas (LNG) is a product of Natural Gas processed by desulfurization and low-temperature liquefaction technologies, and has the characteristics of convenient transportation and storage. However, in the process of liquefying natural gas, the main heat exchanger works in a low-temperature state, and the damage of blocking pipelines and valves due to condensation of LNG can occur.
On the other hand, resources in China are unevenly distributed, energy projects such as west-east power transmission, west-east gas transmission, offshore wind power and LNG stations are built in an accelerated mode, and meanwhile the superconducting power transmission technology is developed rapidly. The LNG cooling superconducting cable is utilized to realize power/LNG integrated transmission, an energy channel is shared, the energy transmission efficiency can be improved, and the cost is reduced. However, superconducting cables are typically operated at temperatures below 90K, at which conventional LNG, whose main component is methane, may freeze and block the pipeline, and the temperatures of the two cannot be well matched.
The above-mentioned problems are caused by the high freezing point of conventional LNG.
Disclosure of Invention
In view of the above, there is a need to provide a method for lowering the freezing point of LNG that can significantly lower the freezing point of LNG without significantly affecting the heat value of combustion thereof, in response to the drawbacks of the prior art.
In order to achieve the purpose, the invention adopts the following technical scheme:
in a first aspect, the present invention provides a method for lowering the freezing point of LNG, comprising the steps of: the freezing point of LNG is reduced to 90K or less by adding short-chain hydrocarbon compound to LNG, wherein the short-chain hydrocarbon compound is at least one of ethane, ethylene, propane, propylene, n-butane, n-butene and n-pentane.
In some preferred embodiments, the LNG is further added with at least one of liquid nitrogen, tetrafluoropropane, or liquid oxygen.
In a second aspect, the present invention provides a method for lowering the freezing point of LNG, comprising the steps of: adding short-chain hydrocarbon compounds to LNG to reduce the freezing point of the LNG to be between 80K and 90K, wherein the short-chain hydrocarbon compounds comprise the following substances in parts by mole: 1-15 parts of ethane, 1-15 parts of propane, 1-17 parts of n-butane, 1-28 parts of isobutane, 1-2 parts of n-pentane, 1-15 parts of ethylene and 1-15 parts of propylene.
In some preferred embodiments, the LNG is further added with at least one of liquid nitrogen, tetrafluoropropane, or liquid oxygen.
In a third aspect, the present invention provides a method for lowering the freezing point of LNG, comprising the steps of: adding short-chain hydrocarbon compounds to LNG to reduce the freezing point of the LNG to be below 80K, wherein the short-chain hydrocarbon compounds comprise the following substances in parts by mole: 16-64 parts of ethane, 16-71 parts of propane, 16-36 parts of ethylene and 16-66 parts of propylene.
In some preferred embodiments, the LNG is further added with at least one of liquid nitrogen, tetrafluoropropane, or liquid oxygen.
In a fourth aspect, the present invention provides a method for lowering the freezing point of LNG, comprising the steps of: adding short-chain hydrocarbon compounds to LNG to reduce the freezing point of the LNG to be below 90K, wherein the short-chain hydrocarbon compounds comprise the following substances in parts by mole: 1-64 parts of ethane, 1-71 parts of propane, 1-17 parts of n-butane, 1-28 parts of isobutane, 1-2 parts of n-pentane, 1-36 parts of ethylene and 1-66 parts of propylene.
In some preferred embodiments, the LNG is further added with at least one of liquid nitrogen, tetrafluoropropane, or liquid oxygen.
The invention adopts the technical scheme that the method has the advantages that:
the method for lowering the freezing point of the LNG provided by the invention has the advantages that the main components of the conventional LNG comprise more than 95% of methane and a small amount of short-chain alkane or olefin components, and the short-chain alkane or olefin such as ethane, propane, n-butane, isobutane, n-pentane, ethylene, propylene and the like has lower freezing point and higher combustion heat value, and the freezing point of the LNG can be obviously lowered by adding the short-chain hydrocarbon compound into the conventional LNG, and the combustion heat value of the LNG is not greatly influenced.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 shows the main component methane (CH) from LNG as provided in example 1 of the present invention4) And ethane (C)2H6) Propane (C)3H8) N-butane (nC)4H10) Isobutane (iC)4H10) Ethylene (C)2H4) Propylene (C)3H6) And a binary mixed solid-liquid equilibrium phase diagram.
FIG. 2 shows the main component methane (CH) from LNG as provided in example 2 of the present invention4) Ethane (C)2H6) And CAlkane (C)3H8) The solid-liquid equilibrium phase diagram of the ternary mixture of the components.
FIG. 3 shows the main component methane (CH) from LNG as provided in example 3 of the present invention4) Ethane (C)2H6) And ethylene (C)2H4) The solid-liquid equilibrium phase diagram of the ternary mixture of the components.
FIG. 4 shows the main component methane (CH) from LNG as provided in example 4 of the present invention4) Ethylene (C)2H4) And propylene (C)3H6) The solid-liquid equilibrium phase diagram of the ternary mixture of the components.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In a first aspect, the present invention provides a method for lowering the freezing point of LNG comprising the steps of: the freezing point of LNG is reduced to 90K or less by adding short-chain hydrocarbon compound to LNG, wherein the short-chain hydrocarbon compound is at least one of ethane, ethylene, propane, propylene, n-butane, n-butene and n-pentane.
In a second aspect, the present invention provides a method for lowering the freezing point of LNG, comprising the steps of: adding short-chain hydrocarbon compounds to LNG to reduce the freezing point of the LNG to be between 80K and 90K, wherein the short-chain hydrocarbon compounds comprise the following substances in parts by mole: 1-15 parts of ethane, 1-15 parts of propane, 1-17 parts of n-butane, 1-28 parts of isobutane, 1-2 parts of n-pentane, 1-15 parts of ethylene and 1-15 parts of propylene.
In a third aspect, the present invention provides a method for lowering the freezing point of LNG, comprising the steps of: adding short-chain hydrocarbon compounds to LNG to reduce the freezing point of the LNG to be below 80K, wherein the short-chain hydrocarbon compounds comprise the following substances in parts by mole: 16-64 parts of ethane, 16-71 parts of propane, 16-36 parts of ethylene and 16-66 parts of propylene.
In a fourth aspect, the present invention provides a method for lowering the freezing point of LNG, comprising the steps of: adding short-chain hydrocarbon compounds to LNG to reduce the freezing point of the LNG to be below 90K, wherein the short-chain hydrocarbon compounds comprise the following substances in parts by mole: 1-64 parts of ethane, 1-71 parts of propane, 1-17 parts of n-butane, 1-28 parts of isobutane, 1-2 parts of n-pentane, 1-36 parts of ethylene and 1-66 parts of propylene.
The method for lowering the freezing point of the LNG provided by the invention has the advantages that the main components of the conventional LNG comprise more than 95% of methane and a small amount of short-chain alkane or olefin components, and the short-chain alkane or olefin such as ethane, propane, n-butane, isobutane, n-pentane, ethylene, propylene and the like has lower freezing point and higher combustion heat value, and the freezing point of the LNG can be obviously lowered by adding the short-chain hydrocarbon compound into the conventional LNG, and the combustion heat value of the LNG is not greatly influenced.
In some preferred embodiments, the LNG is further added with at least one of liquid nitrogen, tetrafluoropropane, or liquid oxygen to further lower the freezing point of the LNG.
The above technical solution is described in detail with reference to specific embodiments below.
Example one
Referring to FIG. 1, the present invention provides a LNG fuel with methane (CH) as the main component4) And ethane (C)2H6) Propane (C)3H8) N-butane (nC)4H10) Isobutane (iC)4H10) N-pentane (nC)5H12) Ethylene (C)2H4) Propylene (C)3H6) The solid-liquid equilibrium phase diagram of the binary mixed working medium. Wherein, when the binary mixture composed of methane and ethane is calculated according to the mole ratio parts of 68 parts of methane and 32 parts of ethane, the binary mixed medium can reach the lowest eutectic temperature of 68.93K.
Example two
Refer to FIG. 2, which is a conventional one according to the present inventionMethane (CH) as the main component of LNG4) And ethane (C)2H6) Propane (C)3H8) The solid-liquid equilibrium phase diagram of the formed ternary mixed medium. When the molar ratio parts of methane 60 parts, ethane 21 parts and propane 19 parts, the ternary mixed medium can reach the lowest eutectic temperature of 64.35K.
EXAMPLE III
Referring to FIG. 3, the present invention provides a LNG fuel containing methane (CH) as the main component4) And ethane (C)2H6) Ethylene (C)2H4) The solid-liquid equilibrium phase diagram of the formed ternary mixed medium. When the molar ratio parts of methane 60 parts, ethane 30 parts and propane 10 parts, the ternary mixing medium can reach the lowest eutectic temperature of 67.81K.
Example four
Referring to FIG. 4, the present invention provides a LNG fuel containing methane (CH) as the main component4) And ethylene (C)2H4) Propylene (C)3H6) The solid-liquid equilibrium phase diagram of the formed ternary mixed medium. When the molar ratio parts of methane 62, ethane 13 and propane 25 are counted, the lowest eutectic temperature of 65.51K can be reached by the ternary mixing medium.
EXAMPLE five
Referring to table 1, in the embodiment of the present invention, the solid phase is precipitated only when the temperature is 70.45K.
TABLE 1 Quaternary mixed cold-storage medium ratio
Methane Ethane (III) Ethylene Propane
Parts by mole ratio 70 10 10 10
The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
Of course, the positive electrode material for lowering the freezing point of LNG according to the present invention may have various modifications and variations, and is not limited to the specific structure of the above-described embodiment. In conclusion, the scope of the present invention should include those changes or substitutions and modifications which are obvious to those of ordinary skill in the art.

Claims (8)

1. A method of lowering the freezing point of LNG comprising the steps of: the freezing point of LNG is reduced to 90K or less by adding short-chain hydrocarbon compound to LNG, wherein the short-chain hydrocarbon compound is at least one of ethane, ethylene, propane, propylene, n-butane, n-butene and n-pentane.
2. The method for depressing the freezing point of LNG as claimed in claim 1 wherein at least one of liquid nitrogen, tetrafluoropropane or liquid oxygen is further added to said LNG.
3. A method of lowering the freezing point of LNG comprising the steps of: adding short-chain hydrocarbon compounds to LNG to reduce the freezing point of the LNG to be between 80K and 90K, wherein the short-chain hydrocarbon compounds comprise the following substances in parts by mole: 1-15 parts of ethane, 1-15 parts of propane, 1-17 parts of n-butane, 1-28 parts of isobutane, 1-2 parts of n-pentane, 1-15 parts of ethylene and 1-15 parts of propylene.
4. The method for depressing the freezing point of LNG as claimed in claim 3 wherein said LNG is further supplemented with at least one of liquid nitrogen, tetrafluoropropane or liquid oxygen.
5. A method of lowering the freezing point of LNG comprising the steps of: adding short-chain hydrocarbon compounds to LNG to reduce the freezing point of the LNG to be below 80K, wherein the short-chain hydrocarbon compounds comprise the following substances in parts by mole: 16-64 parts of ethane, 16-71 parts of propane, 16-36 parts of ethylene and 16-66 parts of propylene.
6. The method for depressing the freezing point of LNG as claimed in claim 5 wherein said LNG is further supplemented with at least one of liquid nitrogen, tetrafluoropropane or liquid oxygen.
7. A method of lowering the freezing point of LNG comprising the steps of: adding short-chain hydrocarbon compounds to LNG to reduce the freezing point of the LNG to be below 90K, wherein the short-chain hydrocarbon compounds comprise the following substances in parts by mole: 1-64 parts of ethane, 1-71 parts of propane, 1-17 parts of n-butane, 1-28 parts of isobutane, 1-2 parts of n-pentane, 1-36 parts of ethylene and 1-66 parts of propylene.
8. The method for depressing the freezing point of LNG as claimed in claim 7 wherein at least one of liquid nitrogen, tetrafluoropropane or liquid oxygen is further added to said LNG.
CN201911083430.3A 2019-11-07 2019-11-07 Method for lowering freezing point of LNG (liquefied Natural gas) Pending CN110835567A (en)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS49109281A (en) * 1973-02-21 1974-10-17
WO2008034526A2 (en) * 2006-09-23 2008-03-27 Linde Aktiengesellschaft Method for supplying natural gas
CN101228595A (en) * 2006-04-10 2008-07-23 住友电气工业株式会社 Superconducting cable
CN109628186A (en) * 2019-02-01 2019-04-16 北京石油化工工程有限公司 It is a kind of to pre-wash technique and device for synthesis gas cryogenic separation

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS49109281A (en) * 1973-02-21 1974-10-17
CN101228595A (en) * 2006-04-10 2008-07-23 住友电气工业株式会社 Superconducting cable
WO2008034526A2 (en) * 2006-09-23 2008-03-27 Linde Aktiengesellschaft Method for supplying natural gas
CN109628186A (en) * 2019-02-01 2019-04-16 北京石油化工工程有限公司 It is a kind of to pre-wash technique and device for synthesis gas cryogenic separation

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
张向宇: "《实用化学手册》", 30 October 2011, 北京：国防工业出版社 *
王建玲 等: "《普通化学》", 31 August 2018, 中国农业大学出版社 *

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