JP2019168207A - Liquefied gas manufacturing system - Google Patents

Abstract

To provide a liquefied gas manufacturing system that can improve economic performance by reducing energy used when cryogenic separation and liquefaction are performed for liquefaction objective gas, and is maintenance free.SOLUTION: A liquefied gas manufacturing system includes: a thermoacoustic engine 90 provided with at least one or more engines 70 and provided with at least one or more acoustic heat pump parts 80; a liquefaction objective gas flow passage La for leading a liquefaction objective gas to a heater 71 and a heat absorber 81 in this described order; and a liquefaction natural gas flow passage Lt for leading a liquefaction natural gas to a radiator 82 and a cooler 72 in this described order.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a liquefied gas production system for liquefying a liquefied gas by using the cold heat of liquefied natural gas.

  Conventionally, a liquefied gas production system is known in which liquefied gas such as nitrogen and oxygen is liquefied by cryogenic separation or the like using the cold heat of liquefied natural gas at an LNG terminal (see Patent Document 1). In the cryogenic separation, the low-boiling point oxygen is first liquefied by compressing the air with a compressor and cooling the liquefied natural gas with cold heat, and then the lower-boiling point nitrogen is liquefied, thereby separating the two. Liquefy.

JP 2003-106723 A

In the technique disclosed in Patent Document 1, the cooling heat applied to the liquefied gas is less than the cooling heat generated when the liquefied natural gas is vaporized, considering the heat exchange efficiency. For this reason, the processing amount per unit time for liquefying the liquefied target gas is limited by the amount that can be liquefied by the cold energy of the liquefied natural gas vaporized per unit time.
Further, the technique disclosed in Patent Document 1 discloses that when liquefying a liquefied gas having a boiling point lower than the boiling point of liquefied natural gas (−162 ° C.) (for example, nitrogen having a boiling point of −196 ° C.), In order to increase the pressure of the compressor, it is necessary to adopt a configuration that always includes a compressor, and since much electric power (energy) is consumed for the operation of the compressor, there is room for improvement from the viewpoint of energy efficiency and economy.

  The present invention has been made in view of the above-mentioned problems, and its object is to reduce the energy associated with the cryogenic separation and liquefaction of the liquefied gas and improve the economic efficiency, and also to produce maintenance-free liquefied gas. To provide a system.

A liquefied gas production system for achieving the above object is as follows.
A liquefied gas production system for liquefying a liquefied gas using the cold heat of liquefied natural gas,
Its characteristic configuration is
An acoustic cylinder filled with a working medium and in which sound waves propagate, a heater that heats the working medium from the outside, a cooler that cools the working medium from the outside, and the acoustic energy of sound waves between the heater and the cooler At least one prime mover comprising a prime mover side regenerator that amplifies the heat, a heat absorber that absorbs heat from the outside of the working medium, a radiator that dissipates heat from the working medium to the outside, the heat absorber, and the radiator A thermoacoustic engine provided with at least one acoustic heat pump unit composed of an acoustic-side regenerator that compresses and expands in a form in which sound waves consume acoustic energy,
A liquefaction target gas flow path for guiding the liquefaction target gas in the order described in the heater and the heat absorber;
It is in the point provided with the liquefied natural gas flow path which guides the liquefied natural gas to the radiator and the cooler in order of description.

According to the above characteristic configuration, the liquefaction target gas flowing through the liquefaction target gas passage is cooled by collecting the cold heat from the cooler with the heater of the prime mover and at the heat absorber of the acoustic heat pump unit. It is cooled in a form in which warm heat is recovered by acoustic energy. As a result, the amount of cold energy recovered per unit time by the gas to be liquefied is larger than the amount of cold heat generated when liquefied natural gas is vaporized per unit time, and the flow rate of liquefied natural gas per unit time is the same. In some cases, it is possible to increase the amount of liquefied natural gas liquefied by the cold as compared with the prior art.
Furthermore, in the acoustic heat pump unit, the temperature of the liquefied gas is increased by the heat pump effect that pumps heat from the liquefied gas passing through the heat absorber to the liquefied natural gas passing through the radiator by the acoustic energy generated by the prime mover. The boiling point of liquefied natural gas (−162 ° C.) can be lowered by about 30 ° C. As a result, the gas to be liquefied having a boiling point lower than that of the liquefied natural gas can be liquefied without increasing the pressure by the compressor, so that it is possible to reduce the driving power of the compressor that occupies most of the power consumption in the prior art. , Energy efficiency can be increased and economic efficiency can be increased.
Moreover, since there are no mechanical moving parts, the risk of failure can be reduced, and a maintenance-free system can be realized.

Further features of the liquefied gas production system
A first heat exchanger that exchanges heat between the liquefied gas and the liquefied natural gas;
The liquefaction target gas flow path is a flow path that guides the liquefaction target gas in the order described in the heater, the first heat exchanger, and the heat absorber,
The liquefied natural gas passage is a passage that guides the liquefied natural gas in the order described in the radiator, the cooler, and the first heat exchanger.

When the flow rate of the liquefied natural gas per unit time is sufficiently larger than the flow rate of the liquefied target gas per unit time, the liquefied target gas can be appropriately liquefied.
On the other hand, when the flow rate of the liquefied target gas per unit time increases, the liquefied target gas may not be completely liquefied even after passing through both the heater and the heat absorber. is assumed.
According to the above characteristic configuration, after the liquefied gas passes through the heater, in the first heat exchanger, the liquefied gas is pre-cooled with the liquefied natural gas that retains the residual cold heat, and then the liquefied gas is Since it is cooled to the boiling point, it is possible to promote the temperature drop by cooling the liquefied target gas while effectively using the residual cold heat of the liquefied natural gas.
As a result, as compared with a configuration in which the first heat exchanger is not provided, the processing amount of the liquefaction target gas per unit time can be increased.

Further features of the liquefied gas production system
A second heat exchanger for exchanging heat between the liquefied gas and the liquefied natural gas;
The liquefaction target gas flow path is a flow path that guides the liquefaction target gas in the order described in the heater, the first heat exchanger, the second heat exchanger, and the heat absorber,
The liquefied natural gas flow path includes a first liquefied natural gas flow path that guides the liquefied natural gas to the radiator, the cooler, and the first heat exchanger, and the liquefied natural gas to the second heat exchanger. It has a second liquefied natural gas passage for guiding natural gas.

  According to the above characteristic configuration, the liquefied gas is cooled by the heater and the first heat exchanger, and then is liquefied natural gas flowing through the second liquefied natural gas flow path by the second heat exchanger. Since it is cooled, it is led to the heat absorber in a sufficiently cooled state, and the state is more reliably changed to a liquefied state below the boiling point by the heat absorber.

Further features of the liquefied gas production system
The downstream end of the second heat exchanger in the second liquefied natural gas passage is at least connected to the downstream side of the radiator in the first liquefied natural gas passage.

The liquefied natural gas after passing through the second heat exchanger of the second liquefied natural gas passage has latent heat, depending on the heat exchange amount in the second heat exchanger and the amount of liquefied target gas. In other words, the temperature is likely to be the boiling point (−162 ° C.) of liquefied natural gas.
Therefore, the liquefied natural gas after passing through the second heat exchanger of the second liquefied natural gas passage is led downstream from the radiator that cools the liquefied gas to the boiling point, and the cooler and the first It can be used for cooling the liquefied gas in the heat exchanger. Thereby, in the heat absorber, the temperature of the liquefying target gas can be appropriately lowered to the boiling point and liquefied, and further energy efficiency can be improved.

Further features of the liquefied gas production system
In a configuration in which a plurality of the prime movers are provided,
The liquefied natural gas flow path is a flow path that guides the liquefied natural gas in series to a plurality of the coolers,
The liquefaction target gas passage is a passage that guides the liquefaction target gas in parallel to the plurality of heaters.

In thermoacoustic engines, research on multi-stage prime movers is underway in order to increase the thermoacoustic conversion energy while lowering the oscillation temperature.
On the other hand, since liquefied natural gas has a lot of latent heat, the temperature is likely to be maintained at the boiling point even after the heat is recovered by passing through the cooler of the prime mover.
Therefore, in a system having a plurality of prime movers, in addition to being able to guide liquefied natural gas maintained at the boiling point in each cooler by guiding liquefied natural gas in series to a plurality of coolers. Since there is no risk of pressure drop due to branching of the flow path, it can be pumped with a single pump.
On the other hand, the liquefaction target gas can be increased in throughput by flowing a plurality of heaters in parallel.

It is a schematic block diagram of the liquefied gas manufacturing system which concerns on 1st Embodiment. It is a schematic block diagram of the liquefied gas manufacturing system which concerns on 2nd Embodiment. It is a figure which shows the arrangement | positioning conditions of the motor | power_engine and the acoustic heat pump part in the case of simulation. It is a graph which shows a simulation result.

The liquefied gas manufacturing system 100 according to the embodiment of the present invention relates to a system that is low in energy and is maintenance-free with low-temperature separation and liquefaction of the liquefied target gas.
Hereinafter, the liquefied gas production system 100 according to the embodiment will be described based on the drawings.

<First Embodiment>
[Configuration related to thermoacoustic engine]
As shown in FIG. 1, the thermoacoustic engine 90 includes an acoustic cylinder T configured by connecting a first loop pipe T1 and a second loop pipe T2 through which a working medium is filled and a sound wave propagates through a connection pipe. In the present embodiment, a single prime mover 70 is provided in the first loop pipe T1, and a single acoustic heat pump unit 80 is provided in the second loop pipe T2.

  A heater 71 that heats the working medium from the outside, a cooler 72 that cools the working medium from the outside, and a motor-side regenerator 73 that amplifies the acoustic energy of sound waves between the heater 71 and the cooler 72. A description of the prime mover 70 will be added.

Although not shown in detail, the heater 71 includes a jacket portion (not shown) through which the gas to be liquefied flows and fins (not shown) extending from the jacket portion to the inside of the acoustic cylinder T. The heater 71 is heated by the liquefaction target gas through which the fins flow through the jacket portion, and heats the working fluid in a form that conducts heat from the fins to the working fluid inside the acoustic cylinder T.
In addition, although various things can be employ | adopted as liquefaction object gas, in the said embodiment, the gas which has a boiling point lower than the boiling point (-162 degreeC) of liquefied natural gas can be employ | adopted suitably, An example is nitrogen. In this embodiment, a configuration is employed in which nitrogen is produced from the air as liquefaction target gas while being separated with liquefaction.

  The cooler 72 includes a jacket portion (not shown) through which liquefied natural gas flows and fins (not shown) extending from the jacket portion to the inside of the acoustic cylinder T. The cooler 72 is cooled by the liquefied natural gas in which the fin flows through the jacket portion, and cools the working fluid in such a manner that cold heat is conducted from the fin to the working fluid inside the acoustic cylinder T.

The prime mover side regenerator 73 provided between the heater 71 and the cooler 72 is, for example, in a state in which the plate surface is aligned in a direction orthogonal to the cylinder axis direction of the acoustic cylinder T in the cylinder axis direction. It is comprised from the thin plate-shaped member (not shown) arranged in a line along.
For example, the thin plate member has a thickness of 50 μm or more and 100 μm or less, and is provided with about 300 to 600 sheets. The thin plate-like member is provided with a large number of through holes (not shown) penetrating in a direction along the cylinder axis direction with a diameter of about 200 μm to 300 μm.

The working fluid exists inside the acoustic cylinder T in a state in which minute fluctuations are generated in the cylinder axis direction. In other words, the sound wave propagating in the working fluid forms a traveling wave from one side to the other side and a traveling wave from the other side to the one side between the heater 71 and the cooler 72.
When forming a traveling wave from the cooler 72 to the heater 71, the sound wave propagating the working fluid passes through a plurality of through holes of a thin plate member as the prime mover side regenerator 73 in the vicinity of the heater 71. Sometimes it is heated in contact with the inner wall of the through-hole and is directly heated by the fins of the heater 71 to expand. On the other hand, when the sound wave propagating the working fluid forms a traveling wave from the heater 71 to the cooler 72 side, a plurality of through holes of the thin plate member as the prime mover side regenerator 73 in the vicinity of the cooler 72 When it passes through, it cools in contact with the inner wall of the through hole and contracts by being cooled directly by the fins of the cooler 72.
Thereby, the sound energy as the traveling wave causes self-excited vibration, and the thermal energy is converted into the acoustic energy of the sound wave in such a form that the acoustic energy is amplified.

  The working medium can be composed of a gas that propagates sound waves. Here, since it is desirable that heat exchange in the prime mover side regenerator 73 be performed quickly, helium and hydrogen having a high thermal diffusion coefficient are desirable as the working medium. For the purpose of power generation, since a gas having a high molecular weight is desirable, a gas such as argon may be mixed. In this embodiment, helium is used as the working medium because it is thermally stable.

The acoustic energy of the sound wave amplified by the prime mover 70 propagates from the first loop tube T1 of the acoustic cylinder T to the acoustic heat pump unit 80 of the second loop tube T2.
The acoustic heat pump unit 80 compresses and compresses the sound energy between the heat absorber 81 where the working medium absorbs heat from the outside, the heat sink 82 where the working medium radiates heat to the outside, the heat absorber 81 and the heat radiator 82 consuming acoustic energy. The sound side regenerator 83 expands.

  Although not shown in detail, the heat absorber 81 includes a jacket portion (not shown) through which the liquefying target gas flows and fins (not shown) extending from the jacket portion to the inside of the acoustic cylinder T. In the heat absorber 81, the fin absorbs heat from the gas to be liquefied flowing through the jacket portion, and the working medium inside the acoustic cylinder T absorbs heat from the fin.

  The radiator 82 includes a jacket portion (not shown) through which liquefied natural gas supplied from the outside flows, and fins (not shown) extending from the jacket portion to the inside of the acoustic cylinder T. In the radiator 82, the working medium inside the acoustic cylinder T radiates heat to the fins, and the liquefied natural gas is heated in such a form that the radiated heat is radiated to the liquefied natural gas flowing through the jacket portion.

The sound-side regenerator 83 provided between the heat absorber 81 and the heat radiator 82 is not different from the prime mover-side regenerator 73 in terms of shape and material.
The cylinder diameter, cylinder length, shape, and the like of the acoustic cylinder T are converted from thermal energy of the prime mover 70 to acoustic energy based on the diameters of the through holes of the prime mover side regenerator 73 and the acoustic regenerator 83, in particular. The efficiency is appropriately set so that the conversion efficiency from the acoustic energy of the acoustic heat pump unit 80 to the thermal energy becomes high.

Here, the acoustic heat pump unit 80 compresses when the sound wave propagating the working fluid forms a traveling wave from the heat absorber 81 to the radiator 82 side, and travels from the radiator 82 to the heat absorber 81 side. The heat absorber 81, the sound side regenerator 83, and the heat radiator 82 are disposed at appropriate positions in the acoustic cylinder T so that the heat absorber 81, and the sound side regenerator 83 and the radiator 82 are expanded. Note that an example of the arrangement of the acoustic heat pump unit 80 and the prime mover 70 for oscillation of the thermoacoustic engine is shown in FIG.
As a result, when the sound wave propagating in the working fluid forms a traveling wave from the heat absorber 81 to the heat radiator 82 side, the working medium absorbs heat while being compressed by the acoustic side regenerator 83 to raise the temperature and release heat. The heat is released in a state where the temperature is raised by the vessel 82 and becomes high. Thereby, in the heat radiator 82, the liquefied natural gas flowing through the jacket portion is heated in a form of heat exchange with the working medium having a temperature higher than that of the liquefied target gas flowing through the jacket portion of the heat absorber 81.
On the other hand, when the sound wave propagating in the working fluid forms a traveling wave from the radiator 82 toward the heat absorber 81, the working medium radiates and cools down while expanding in the acoustic side regenerator 83, and the heat absorber 81. The heat is absorbed in a state where the temperature is lowered at low temperature. As a result, in the heat absorber 81, the working medium that is sufficiently cooler than the liquefied natural gas flowing through the jacket portion of the radiator 82 from the liquefied target gas flowing through the jacket portion absorbs heat well.
Incidentally, as described above, in the step of absorbing heat while compressing by the acoustic side regenerator 83 and the step of releasing heat while expanding, the acoustic energy of the sound wave is consumed and the sound wave is attenuated, but the acoustic energy is received from the prime mover 70. Since the replenishment is performed sequentially, the heat pump function of the acoustic heat pump unit 80 is maintained.

  As described so far, the liquefied natural gas or the liquefied target gas flows through the heater 71 and the cooler 72 of the prime mover 70 and the heat absorber 81 and the radiator 82 of the acoustic heat pump unit 80, respectively. In order to optimize the efficiency of the thermoacoustic engine and improve the production amount of the liquefied target gas produced with respect to the liquefied natural gas per unit flow rate, both the flow path and the flow rate adjusting valve V are as follows: It is arranged like this.

The liquefaction target gas flow path La through which the liquefaction target gas flows is a flow path through which the liquefaction target gas such as air fed by a pressure feed pump (not shown) flows, and at least the heater 71 and the heat absorber 81. And liquefying target gas is arranged in the order described in the above.
Here, when the gas to be liquefied is nitrogen (usually air containing nitrogen), the gas to be liquefied needs to be finally cooled to the boiling point of nitrogen (−196 ° C.) by recovering sensible heat. Furthermore, it is necessary to recover the latent heat when the gas to be liquefied changes state from gas to liquid.
In this embodiment, the liquefaction target gas needs to be a product (liquid) from which heat has been most recovered after passing through the heat absorber 81 of the acoustic heat pump unit 80. For this reason, it is necessary to lower the temperature of the liquefaction target gas led to the heat absorber 81 to a temperature close to the boiling point (−196 ° C.) of the liquefaction target gas.
However, although depending on the flow rate and temperature of the liquefied target gas flowing through the heater 71 of the prime mover 70 and the flow rate and temperature and state (liquid or gas) of the liquefied natural gas flowing through the cooler 72, the heater 71 The gas to be liquefied after passing through may not be sufficiently cooled to a temperature close to the boiling point.
Therefore, in the present embodiment, the liquefaction target gas flow path La includes the first heat exchanger EX1 that exchanges heat between the liquefaction target gas and the liquefied natural gas after passing through the heater 71, and the first heat exchanger EX1. The gas to be liquefied is passed through the second heat exchanger EX2 that exchanges heat between the gas to be liquefied and the liquefied natural gas after passing through the heat exchanger in the order described.
In this embodiment, air is circulated through the liquefaction target gas flow passage La as the liquefaction target gas, but liquid oxygen is generated during the cooling process. Since the boiling point of the oxygen is −163 ° C., when the temperature passes through the heat absorber 81 and is lower than −163 ° C. and higher than the boiling point of nitrogen −196 ° C., a cryogenic separation or the like is performed by a rectification tower (not shown). Will be.

The liquefied natural gas passage Lt is a passage through which the liquefied natural gas flows, and is arranged so that the liquefied natural gas flows at least in the order described in the radiator 82 and the cooler 72.
The liquefied natural gas flow path Lt includes a first liquefied natural gas flow path Lt1 that guides liquefied natural gas in the order described in the radiator 82, the cooler 72, and the first heat exchanger EX1, and a second heat exchanger. After the liquefied natural gas is guided to EX2, the second liquefied natural gas flow path Lt2 is connected to the first liquefied natural gas flow path Lt1 between the cooler 72 and the first heat exchanger EX1.
At the upstream branch portion between the first liquefied natural gas flow path Lt1 and the second liquefied natural gas flow path Lt2, the first liquefied natural gas flow path Lt1 side and the second liquefied natural gas flow path Lt2 A flow rate adjustment valve V that can control the flow rate ratio of the liquefied natural gas to the side is provided, and the flow rate control valve V controls the flow rate ratio to an appropriate flow rate.

Second Embodiment
Now, in the liquefied gas manufacturing system 100 demonstrated in 1st Embodiment, the structural example provided with the single motor | power_engine 70 and the single acoustic heat pump part 80 was shown. A plurality of the prime mover 70 and the acoustic heat pump unit 80 may be provided. In particular, research is being conducted to lower the oscillation temperature of a thermoacoustic engine, which is generally as high as 300 ° C. to 700 ° C., by making the prime mover 70 multistage.
In the liquefied gas manufacturing system 100 according to the second embodiment, a configuration example in which two prime movers 70 are provided in the first loop pipe T1 is shown. In the liquefied gas manufacturing system 100 according to the second embodiment, the configuration including the two prime movers 70 and the flow path configuration associated therewith are different, and other configurations are related to the first embodiment. Since it is the same as the liquefied gas manufacturing system 100, description will be omitted.

  As shown in FIG. 2, the liquefied gas production system 100 according to the second embodiment includes the first prime mover 70a and the second prime mover 70b in the first loop pipe T1, and the first prime mover 70a constituting the first prime mover 70a. 1 heater 71a, 1st cooler 72a, 1st prime mover side regenerator 73a, 2nd prime mover 70b which constitutes 2nd prime mover 70b, each composition of 2nd cooler 72b, 2nd prime mover side regenerator 73b Are the same as the configurations of the heater 71, the cooler 72, and the prime mover side regenerator 73 of the prime mover 70 of the first embodiment.

Now, depending on the flow rate of the liquefied natural gas that flows through the radiator 82 of the acoustic heat pump unit 80 and the flow rate, temperature, and state (liquid or gas) of the liquefied target gas that flows through the heat absorber 81, the radiator 82. The liquefied natural gas after passing through may also have sufficient latent heat.
In such a case, the first liquefied natural gas flow path Lt1 is in series with the plurality of coolers (in the second embodiment, the first cooler 72a and the second cooler 72b). It is preferable to arrange the liquefied natural gas to flow therethrough. By adopting this configuration, compared with the case where the first liquefied natural gas flow path Lt1 is branched, the flow rate is sufficient for each of the plurality of coolers and the boiling point (-162 ° C.) is sufficiently low. Liquefied natural gas can be guided.

  On the other hand, the liquefaction target gas flow path La through which the liquefaction target gas flows is approximately the same between the heater 71 and the cooler 72 in each of the plurality of prime movers (first prime mover 70a and second prime mover 70b). In order to efficiently generate acoustic energy, it is preferable to adopt a configuration in which the liquefying target gas is guided in parallel to each of the first heater 71a and the second heater 71b. That is, in the liquefied gas manufacturing system 100 according to the second embodiment, the liquefying target gas flow passage La has the first liquefying target gas flow passage La1 that guides the liquefied target gas to the first heater 71a, and the second heating. And a second liquefaction target gas passage La2 that guides the liquefaction target gas to the vessel 71b.

[Estimated results]
Regarding the liquefied gas production system 100 according to the second embodiment, the motor 70 and the acoustic heat pump when the thermoacoustic engine oscillates and liquefyes the liquefied target gas and when the configuration according to the second embodiment is adopted. A simulation was performed to show an example of the shape / arrangement state with the unit 80 and an example of the flow rate / temperature balance between the liquefied target gas and the liquefied natural gas in that state.
In the simulation, in the liquefied gas production system shown in FIG. 2, the acoustic cylinder T has an inner diameter of 30 mm, the hydraulic radius of the prime mover side regenerator 73 and the acoustic side regenerator 83 is 0.019 mm, the porosity is 85%, The mesh of the metal mesh as the thin plate member of the vessel was 0.057 mm, the wire diameter was 0.016 mm, and the working medium was 6 Mpa helium. Further, the axial length of the first motor side regenerator 73a is 0.03 m, the axial length of the second motor side regenerator 73b is 0.03 m, and the axial length of the acoustic side regenerator 83 is .0. It was 25 m.

  The wavelength is sufficiently long compared to the particle size (the particle velocity in the plane direction (axial direction) is sufficiently small, the pressure and density in the axial direction of the acoustic cylinder are constant, the inner wall surface of the acoustic cylinder On the condition that the thermal diffusion and viscosity dissipation depending on the distance from the cross section are averaged and made one-dimensional, the continuous equation [Equation 1], the Navier-Stokes equation [Equation 2], and the general equation for heat transport From [Equation 3], [Equation 4] was obtained.

〔数１〕、〔数２〕、〔数３〕において、ρは密度、ｕは軸方向粒子速度、ｖは軸径方向粒子速度、Ｔは温度、Ｃｐは定圧比熱、λは熱伝導率、ｘは軸方向座標、ｒは軸径方向座標、μは粘性係数である。

In [Equation 1], [Equation 2], and [Equation 3], ρ is density, u is axial particle velocity, v is axial radial particle velocity, T is temperature, Cp is constant pressure specific heat, λ is thermal conductivity, x is an axial coordinate, r is an axial radial coordinate, and μ is a viscosity coefficient.

ここで、Ｐは圧力振幅、〈ｕ〉_ｒは断面平均体積流速振幅（粒子速度振幅）、ｊは虚数、ωは角周波数、ρ_ｍは平均密度、Ｐ_ｍは平均圧力、γは比熱比、σはプラントル数、Ｔ_ｍは平均温度である。
また、χ_αは筒軸径方向での熱拡散分布の平均とし、χ_ｖは筒軸径方向での粘性散逸分布の平均である。

Here, P is a pressure amplitude, <u> _r is a cross-sectional average volume flow velocity amplitude (particle velocity amplitude), j is an imaginary number, ω is an angular frequency, ρ _m is an average density, P _m is an average pressure, γ is a specific heat ratio, σ is the Prandtl number and T _m is the average temperature.
Χ _α is the average of the thermal diffusion distribution in the cylinder axis radial direction, and χ _v is the average of the viscous dissipation distribution in the cylinder axis radial direction.

When the eigenvalues and eigenvectors of the matrix A in [Equation 4] are obtained and diagonalized, information on continuous x points is obtained using P (0) and U (0) at x = 0 (x _{0 in} FIG. 3). The following [Equation 5] is obtained.

ただし、

However,

  Further, the whole sound field is obtained by connecting [Equation 5] as shown in [Equation 6] below for each continuous space.

First, P (x ₀ ) and U (x ₀ ) at the start point of the first loop tube T1 in FIG. 3, U (x ₉ ) at the end point of the first loop cylinder T1, and [Equation 5] are obtained. using the transfer matrix C _e of the first loop pipe T1 which is, from the boundary condition that the pressure amplitude equal at the junction point between the start and end points of the first loop pipe T1, the following [Equation 7] is satisfied.

Similarly, P (x ₁₀ ) and U (x ₁₀ ) at the start point of the second loop pipe T2 in FIG. 3 and U (x ₁₅ ) at the end point of the second loop pipe T2 are connected to [Equation 5]. Using the obtained transfer matrix C _f of the second loop tube T2, the following [Equation 8] is established from the boundary condition that the pressure amplitude at the junction between the start point and the end point of the second loop tube T2 is equal.

Finally, the volume flow velocity amplitudes at the junction x _r1 between the connecting pipe and the first loop pipe T1 and at the junction x _r2 between the connecting pipe and the second loop pipe T2 are U (x _r1 ) and U (x _r2 ), respectively. Then, the following relationships [Equation 9] [Equation 10] exist.

The transfer matrix of the connecting pipe and C _r, the use of [number 9], [number 10], [Equation 11] is obtained.

  When [Formula 7], [Formula 8], and [Formula 11] are connected and P and U are deleted, the following [Formula 12] is obtained.

In [Equation 12], the terms of pressure amplitude P and cross-sectional average volume flow velocity amplitude <u> _r do not exist, so that the operating condition can be determined without depending on the magnitude of the vibration amount. When the regenerator temperature, the regenerator channel diameter, etc. included in the A matrix and the apparatus shape information included in the C matrix are changed, the condition satisfying [Equation 12] is the operating condition.

As conditions satisfying [Equation 12], the inventors of the present invention in FIG. 3, x ₀ = 0 m, x ₁ = 1.4 m, x ₂ = 1.43 m, x ₃ = 1.46 m, x ₄ = _{1.49m, x 5 = 1.54m, x} 6 = 1.57m, x 7 = 1.60m, x 8 = 1.63m, x 9 = 1.81m, x 10 = 1.5.62m, x 11 = 6.97 m, x ₁₂ = 7.00 m, x ₁₃ = 7.25 m, x ₁₄ = 7.28 m, x ₁₅ = 7.45 m, the shape and arrangement of the prime mover 70, the acoustic heat pump unit 80, and the acoustic cylinder T It was determined.

  Furthermore, when the initial state of the liquefied natural gas flowing through the first liquefied natural gas passage Lt1 is 100% liquid and the flow rate is 1 t / h, it passes when passing through the heat absorber 81 at −162 ° C. When the heat of 69 kW is recovered in a state of changing from 100% of the previous liquid to 50% of the liquid after passage and passing through the first cooler 72a at −162 ° C., the liquid 50% of the liquid 50% before passage is 50%. 30% of the heat is recovered in a form that changes from 71% to 71% liquid 29% after passing, and when passing through the second cooler 72b at -162 ° C, after passing from 71% liquid 29% gas before passing. It was estimated that 13 kW of heat was recovered while changing the state to 19% liquid and 81% gas, and then passed through the first heat exchanger EX1. Furthermore, the liquefied natural gas flowing through the second liquefied natural gas passage Lt2 has a flow rate of 1 t / h and passes through the second heat exchanger EX2 and the first heat exchanger EX1 in the order described.

Moreover, when the initial state of air (nitrogen) as the liquefaction target gas flowing through the first liquefaction target gas passage La1 is 100% gas and the flow rate is 3.8 t / h, the first heater 71a is By flowing in at 30 ° C. and flowing out at −30 ° C., 65 kW of heat was supplied. The liquefaction target gas flowing through the second liquefaction target gas passage La2 has a flow rate of 1.6 t / h, flows into the second heater 71b at 30 ° C., and flows out at −30 ° C. Estimated to supply heat. The liquefaction target gas that has flowed through the first liquefaction target gas passage La1 and the second liquefaction target gas passage La2 is cooled by the first heat exchanger EX1 and the second heat exchanger EX2, and then the flow rate is increased. It was estimated that 19 kW was dissipated in the form of 2.7 t / h of nitrogen at −162 ° C., passing through the radiator 82, falling to the boiling point of −196 ° C. and becoming 100% liquid.
It is confirmed that the above [Equation 12] is satisfied under the conditions, and 35 kW of acoustic energy is generated in the first prime mover side regenerator 73a, and 15 kW of acoustic energy is generated in the second prime mover side regenerator 73b. It was estimated that the acoustic energy of 50 kW was consumed by the device 83.
Further, the pressure amplitude, acoustic energy, and particle velocity amplitude at each position in the axial direction of the acoustic cylinder T were calculated as shown in FIG.

[Another embodiment]
(1) In the said embodiment, although the structure provided with the 1st heat exchanger EX1 and the 2nd heat exchanger EX2 was shown, when the flow volume of liquefied natural gas can fully ensure with respect to the flow volume of liquefaction object gas etc. Then, the structure which does not provide the said 1st heat exchanger EX1 and the 2nd heat exchanger EX2 may be employ | adopted, and the structure which provides either one may be employ | adopted.
Moreover, when not providing 2nd heat exchanger EX2, the structure which does not provide 2nd liquefied natural gas passage Lt2 is employ | adopted.

(2) In the first embodiment, the second liquefied natural gas passage Lt2 on the downstream side of the second heat exchanger EX2 is the first liquefied natural gas between the cooler 72 and the first heat exchanger EX1. The configuration in which the communication channel Lt1 is connected in communication is shown.
However, the second liquefied natural gas flow path Lt2 may be configured to be connected to the first liquefied natural gas flow path Lt1 between the heat absorber 81 and the cooler 72.
As a result, the cold heat of the liquefied natural gas after passing through the second heat exchanger EX2 can be used not only in the first heat exchanger EX1 but also in the cooler 72.
In addition, when the second liquefied natural gas flow path Lt2 on the downstream side of the second heat exchanger EX2 is in a state where it does not hold cold, it passes other equipment such as the first heat exchanger EX1. Alternatively, a configuration that leads to a downstream city gas passage (not shown) may be employed.

In the above-described embodiment, an example in which liquefied nitrogen is produced without pressurizing air is shown, but a configuration in which air is pressurized may be adopted. For example, by pressurizing the air to about 1 MPa, the liquefaction temperature of oxygen becomes about −155 °. Therefore, the second heat exchanger EX2 adopts a configuration in which oxygen is cryogenically separated by a rectification tower or the like (not shown). it can.
The pressure in the configuration for performing the pressurization is sufficiently lower than the pressurization pressure (for example, 3.7 MPa) in a conventional liquefied gas production facility that does not use a thermoacoustic engine. For this reason, it is possible to reduce power consumption. Moreover, since oxygen can be deep-cooled and separated by the second heat exchanger EX2, a simple configuration can be adopted as compared to the configuration described in the above embodiment.

  The configuration disclosed in the above embodiment (including another embodiment, the same shall apply hereinafter) can be applied in combination with the configuration disclosed in the other embodiment, as long as no contradiction occurs. The embodiment disclosed in this specification is an exemplification, and the embodiment of the present invention is not limited to this. The embodiment can be appropriately modified without departing from the object of the present invention.

  INDUSTRIAL APPLICABILITY The liquefied gas production system of the present invention can be used effectively as a maintenance-free liquefied gas production system that can improve the economy by reducing the energy associated with the cryogenic separation and liquefaction of the gas to be liquefied.

70: prime mover 71: heater 72: cooler 73: prime mover side regenerator 80: acoustic heat pump unit 81: heat absorber 82: radiator 83: acoustic side regenerator 90: thermoacoustic engine 100: liquefied gas production system EX1: first 1 heat exchanger EX2: second heat exchanger La: liquefaction target gas flow path La1: first liquefaction target gas flow path La2: second liquefaction target gas flow path Lt: liquefied natural gas flow path T: acoustic Tube

Claims (5)

A liquefied gas production system for liquefying a liquefied gas using the cold heat of liquefied natural gas,
An acoustic cylinder filled with a working medium and in which sound waves propagate, a heater that heats the working medium from the outside, a cooler that cools the working medium from the outside, and the acoustic energy of sound waves between the heater and the cooler At least one prime mover comprising a prime mover side regenerator that amplifies the heat, a heat absorber that absorbs heat from the outside of the working medium, a radiator that dissipates heat from the working medium to the outside, the heat absorber, and the radiator A thermoacoustic engine provided with at least one acoustic heat pump unit composed of an acoustic-side regenerator that compresses and expands in a form in which sound waves consume acoustic energy,
A liquefaction target gas flow path for guiding the liquefaction target gas in the order described in the heater and the heat absorber;
A liquefied gas production system comprising a liquefied natural gas passage for guiding the liquefied natural gas in the order of description to the radiator and the cooler. A first heat exchanger that exchanges heat between the liquefied gas and the liquefied natural gas;
The liquefaction target gas flow path is a flow path that guides the liquefaction target gas in the order described in the heater, the first heat exchanger, and the heat absorber,
2. The liquefied gas production system according to claim 1, wherein the liquefied natural gas flow path is a flow path that guides the liquefied natural gas in the order of the radiator, the cooler, and the first heat exchanger. A second heat exchanger for exchanging heat between the liquefied gas and the liquefied natural gas;
The liquefaction target gas flow path is a flow path that guides the liquefaction target gas in the order described in the heater, the first heat exchanger, the second heat exchanger, and the heat absorber,
The liquefied natural gas flow path includes a first liquefied natural gas flow path that guides the liquefied natural gas to the radiator, the cooler, and the first heat exchanger, and the liquefied natural gas to the second heat exchanger. The liquefied gas manufacturing system according to claim 2, further comprising a second liquefied natural gas passage for guiding natural gas.   The downstream end of the second heat exchanger of the second liquefied natural gas flow path is connected to at least a downstream side of the radiator of the first liquefied natural gas flow path. Liquefied gas production system. In a configuration in which a plurality of the prime movers are provided,
The liquefied natural gas flow path is a flow path that guides the liquefied natural gas in series to a plurality of the coolers,
The liquefied gas production system according to any one of claims 1 to 4, wherein the liquefaction target gas passage is a passage through which the liquefaction target gas is guided in parallel to the plurality of heaters.

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