JP5313737B2 - Mixed gas supply device and composition variation adjustment method in mixed gas supply device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mixed gas feeder suitable for stabilizing the calorific value of a fuel gas such as a town gas, and to provide a composition fluctuation-regulating method therefor. <P>SOLUTION: The mixed gas feeder is constituted as follows. An attaching position (X) of a gas offtake part is set based on the whole length (L) of the effective part of an adsorption column so as to satisfy the relation of L/2&lt;X&lt;L. A deviation is caused in the phases of the composition fluctuation between the gas from the gas outlet and the gas from the offtake part X. As a result, the composition fluctuation can be further reduced by canceling the fluctuations by mixing of both the gases downstream of the absorption column. Especially, it is proved that the composition fluctuation-reducing effect is maximized at the vicinity of X=0.75. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

The present invention relates to a mixed gas supply device and a composition variation adjusting method thereof, and more particularly to a mixed gas supply device suitable for stabilizing a calorific value of fuel gas such as city gas and a composition variation adjusting method thereof.

In recent years, LNG (liquefied natural gas) satellite bases have been built with increasing demand for city gas in regions far from metropolitan areas. The LNG satellite base is a facility equipped with an LNG storage tank and a vaporizer. After transporting LNG from the coastal LNG receiving terminal by lorry and storing it in the LNG storage tank, the LNG is vaporized to industrial parks and residential areas. It is for supply as city gas.
In such an LNG satellite supply system, there may be a problem of supply gas composition fluctuation (calorific value fluctuation) at the start of carburetor operation, load fluctuation, temperature change and the like. For this reason, various techniques for stabilizing the calorific value of the supply gas have been proposed. Among them, as a useful technique, a calorific value adjusting method and system using an adsorbent are disclosed (for example, patents). References 1 to 3).

The applicants have proposed a technique that focuses on the phase of composition variation as a more advanced composition variation stabilization technique. That is, Patent Document 4 is an invention using two or more kinds of adsorbents having different adsorption / desorption characteristics, and Patent Document 5 is an invention in which one or more branch pipes are provided to overlap the phases of fluctuation. Furthermore, Patent Document 6 suppresses composition fluctuation by arranging a plurality of adsorption towers filled with adsorbents having different adsorption / desorption characteristics and selecting an optimum adsorption tower according to the gas composition and temperature. .

FIG. 12 shows a configuration of a combustion gas supply device 100 according to Patent Document 5, in which LNG in the LNG storage tank 101 is gasified by the vaporizer 102, and an adsorption tower 103 provided in parallel in the path of the branch pipes 105a and 106a. 104. Valves 109 and 110 are disposed in each branch pipe path. In the adsorption tower, the amount of generated heat is suppressed by the action of the adsorbent in the adsorption tower, passes through the pipes 105b and 106b after passing through the adsorption tower, and is supplied as fuel gas after merging. Here, the extension on the pipe 105b side is longer than the pipe 106b side, and the pipe 105b is provided with a plurality of outlets 107, and the pipe extension is variable.
The combustion gas supply device 100 performs a combination of flow rate ratio adjustment by adjusting the opening degree of the valves 109 and 110 and pipe extension adjustment of the pipe 105b based on the measurement value of the calorimeter 108, thereby enabling to suppress the calorific value fluctuation.

JP 2004-331948 A JP 2005-273753 A JP 2005-305218 A JP 2008-201890 A JP 2008-214565 A JP 2008-231357 A

  According to Patent Documents 4 to 6, a higher degree of composition fluctuation suppression can be achieved as compared with the conventional technique. However, according to the technique of Patent Document 4, two or more types of adsorbents having different adsorption characteristics are required, and the techniques of Patent Documents 5 and 6 require a plurality of adsorption towers, which makes the apparatus configuration complicated and large. . For this reason, it becomes a subject to provide a composition variation suppression technique using a simpler configuration and a single adsorbent.

The present invention is for solving the above-described problem, and the composition variation is kept constant without increasing the adsorbent filling amount of the adsorption tower by the single adsorbent and the mixed gas supply device by one adsorption tower. It is an object of the present invention to provide a mixed gas supply device that enables gas supply while being limited to a range.
The gist of the present invention is as follows. That is, the mixed gas supply device according to the present invention is
(1) A mixed gas supply apparatus comprising an adsorption tower filled with an adsorbent in a mixed gas supply line path whose gas composition varies with time, and the adsorption tower is connected to an upstream pipe of the supply line An adsorbing tower, a gas outlet connected to a downstream pipe (main pipe) of a supply line, and a gas outlet at a position downstream from the middle of the gas inlet and the gas outlet. On the downstream side, the flow rate ratio of the mixed gas passing through the downstream pipe and the bypass pipe in the bypass pipe connecting the gas extraction part and the junction of the downstream pipe and the path to the junction of the downstream pipe And a flow rate ratio control unit that adjusts and can control the composition fluctuation range of the mixed gas after merging.

The amount of suppression of the gas composition fluctuation range is originally determined by the adsorbent filling amount, but according to the present invention, the fluctuation range suppression exceeding the above limit is made possible by utilizing the fact that the phase difference of the gas composition fluctuation differs depending on the position of the adsorption tower outlet. Is possible. Here, “phase” is a concept that means the time and timing until the result appears on the downstream side when a periodic or aperiodic composition fluctuation occurs. Furthermore, the “phase difference” is a concept that means a phase shift.
FIG. 1 is a diagram schematically showing the configuration of the present invention. The attachment position (X) of the gas extraction part is set so that L / 2 <X <L with respect to the full length (L) of the adsorption tower effective part. By setting at this position, a phase shift occurs in the composition variation between the gas from the gas outlet and the gas from the extraction portion X. Therefore, by mixing both gases on the downstream side of the adsorption tower, the fluctuation is canceled and the composition fluctuation can be further suppressed.

In the present invention, “gas composition variation” is not limited to periodic variation, but includes non-periodic variation, and includes not only continuous variation but also single variation.
In the present invention, the “mixed gas” is a concept including a raw material gas, a by-product gas, an exhaust gas, a produced gas by biomass, and the like in the chemical industry.
In addition, as the “adsorbent” used in the present invention, activated carbon, zeolite, silica gel, mesoporous silica, activated alumina, organometallic complex, and the like can be used. Examples of the activated carbon include coal raw material activated carbon, coconut husk activated carbon, charcoal, petroleum raw material activated carbon, bamboo charcoal, phenol resin activated carbon, rayon-derived activated carbon, acrylonitrile-derived activated carbon, grass charcoal, sawdust charcoal, and peat.

(2) In the above invention, the gas extraction portion can be provided at a position of 0.6 L or more and less than 1.0 L with respect to the effective length (L) of the adsorption tower.
(3) More preferably, a gas extraction part can be provided in the position of 0.75L vicinity with respect to the said adsorption tower effective length (L).
As will be described later, it has been proved that the composition variation suppressing effect is maximized in the vicinity of X = 0.75.
(4) In each of the above inventions, the composition fluctuation phase difference generating means is further provided in at least one of the downstream pipe or the bypass pipe.
By producing a difference in the phase of composition fluctuation of the gas passing through both pipes, it is possible to further promote suppression of composition fluctuation of the gas after merging.
As the “phase difference generating means”, a pipe flow path difference, a pressure difference, or the like can be used.
(5) In the above (4), as the phase difference generation means, means for extending the pipe length of the downstream pipe or the bypass pipe can be used.
By extending the length of either one of the pipes, the phase of the mixed gas passing through the pipe can be delayed.
(6) In each of the above inventions, fuel gas can be used as the “mixed gas”.
(7) Moreover, it can be set as city gas which has methane as a main component.

The composition variation control method of the mixed gas supply apparatus according to the present invention is:
(8) The above mixed gas supply apparatus is characterized in that the composition fluctuation of the mixed gas after merging is controlled within a desired range by adjusting the flow ratio by the flow ratio control means.
(9) By adjusting the flow rate ratio of the fuel gas or city gas whose gas composition changes over time by the flow rate control means, the calorific value of the combined fuel gas or city gas is adjusted within a predetermined range. It is characterized by doing.
The calorific value adjustment device according to the present invention is
(10) The mixed gas supply apparatus according to the above (6) or (7), wherein the calorific value of the fuel gas or the city gas after passing through the adsorption tower can be adjusted within a predetermined range. And
Currently, city gas nationwide is classified into 14 types of gas groups based on the Wobbe index and burning rate index, and city gas companies can supply city gas of the specified gas type to consumers in the supply area. As required by the Gas Business Law. For example, 13A city gas mainly composed of methane is defined as 52.7 ≦ WI ≦ 57.8 and 35 ≦ MCP ≦ 47. Here, WI is the Wobbbe index, and MCP is the combustion rate index, and details such as specific numerical values are shown in the Gas Business Law, and are omitted here.
Therefore, by controlling the WI and MCP of the mixed gas after passing through the calorific value adjusting device according to the present invention within the range of, for example, 13A city gas, the city gas 13A equipment can be burned well in the supply area.

According to the present invention, it is possible to provide a mixed gas supply apparatus that enables gas supply while suppressing composition fluctuation within a certain range only by using a single adsorbent and a single adsorption tower.
Further, in the invention using fuel gas or city gas as the mixed gas, even if the gas accompanied by the calorific value fluctuation is supplied from the supply source, the calorific value fluctuation is suppressed to a certain range and the customer is It becomes possible to supply.

It is a figure which shows the structure of this invention typically. It is a figure which shows the pore size distribution of the activated carbon which is an adsorbent used for the test. It is a figure which shows the pressure-adsorption amount characteristic with respect to methane and propane of activated carbon same as the above. 1 is a diagram showing an outline of a test apparatus 1 of Example 1. FIG. It is a figure which shows the emitted-heat amount fluctuation | variation time transition at the flow rate ratio 80:20 in Example 1. FIG. It is the elements on larger scale of FIG. It is a figure which shows the calorific value fluctuation | variation time transition at the time of the flow ratio 62:38 in Example 1. FIG. It is the elements on larger scale of FIG. It is a figure which shows the relationship between the taking-out position in Example 1, a fluctuation range, and the time difference of a phase. It is a figure which shows the outline | summary of the test apparatus 20 of Example 2. FIG. In Example 2, it is a figure which shows the difference in the emitted-heat amount fluctuation | variation width by the presence or absence of a flow-path difference. It is a figure which shows the structure of the conventional calorific value adjustment apparatus.

  Hereinafter, in order to confirm the composition variation suppressing effect according to the present invention, the contents of a test using a combustion gas whose composition (heat generation amount) periodically varies as a test gas will be described.

(Test adsorption material)
Coal activated carbon was used as the adsorbent. The physical properties of the activated carbon are shown in Table 1, and the pore size distribution (by nitrogen adsorption DFT method) is shown in FIG. FIG. 3 shows the pressure-adsorption amount characteristics of activated carbon for methane and propane.

（試験ガス）
２分間、ＬＮＧ気化ガス（組成：CH4：90.8%、C2H6：5.0%、C3H8：3.0%、i-C4H10：0.6%、n-C4H10：0.6%）を流し、その後１分間、このガスに添加用ガス（プロパン：ブタン＝１：１）を添加するサイクルを繰り返すことにより、周期的に組成（発熱量）が変動するガスを調製した。試験ガスの発熱量変動は、４４．５〜５１．０（ＭＪ/ｍ３）であり、ΔＨ＝３．２５（ＭＪ/ｍ３）であった。ここに、ΔＨは ΔＨ＝（Ｈｍax−Ｈmin）／２、すなわち発熱量最大値Ｈｍaxと最小値Ｈminの差の１/２であり、発熱量変動幅比較の指標となる数値である。

(Test gas)
Flow LNG vapor (composition: CH4: 90.8%, C2H6: 5.0%, C3H8: 3.0%, i-C4H10: 0.6%, n-C4H10: 0.6%) for 2 minutes, then add to this gas for 1 minute By repeating the cycle of adding gas (propane: butane = 1: 1), a gas whose composition (calorific value) fluctuates periodically was prepared. The calorific value variation of the test gas was 44.5 to 51.0 (MJ / m3), and ΔH = 3.25 (MJ / m3). Here, ΔH is ΔH = (Hmax−Hmin) / 2, that is, 1/2 of the difference between the maximum calorific value Hmax and the minimum value Hmin, and is a numerical value serving as an index for comparing the calorific value fluctuation range.

(Test equipment)
As shown in FIG. 4, the test apparatus 1 was used as an adsorption tower by filling a horizontally placed container 2 (with an internal volume of 30 cc) with 12 g of an adsorbent. In addition to the gas inlet 10 and the gas outlet 11, the container 2 is provided with gas outlets A, B, and C on the side surfaces. The gas outlets A, B, and C are set to positions L / 4, L / 2, and 3L / 4 from the gas inlet 10 as the total container length (L), respectively.
Hereinafter, taking the case of connecting to the outlet C as an example, the gas that exits the outlet 11 and passes through the main pipe 4 and the gas that exits the outlet C and passes through the bypass pipe 5 are connected at the downstream junction 6. Merge. A throttle valve 7 and a calorimeter 8a (manufactured by Advantica, product name: GasPT) are attached to the main pipe 4, and a mass flow meter (MFC) 9 and a calorimeter 8b are attached to the bypass pipe 5. The same applies when connecting to the outlets A and B. However, the pipe length from each outlet to the mass flow meter 9 is adjusted to be constant so that there is no difference in the fluctuation phase due to the flow path difference.

(Test method)
A test gas was allowed to flow into the container 2 under an inflow condition of a superficial velocity of 2000 h ⁻¹ (supply amount 1 L / min) and a temperature of 25 ° C. Next, the mass flow meter 9 and the throttle valve 7 were used to adjust the flow ratio (F1: F2) between the main pipe 4 side flow rate and the bypass pipe 5 side flow rate to (a) 80:20 or (b) 62:38. . In this state, the calorific value fluctuation of the gas flowing through both pipes was measured by calorimeters 8a and 8b, respectively. The same measurement was performed when the bypass pipe 5 was connected to the outlets A and B.

(Measurement result)
FIG. 5 shows the time transition of the calorific value fluctuation of the gas from the outlet 11 and the outlets A, B, C when the flow ratio is 80:20. FIG. 6 is a partially enlarged view thereof. Table 2 shows the numerical values of the phase time difference from the outlet 11 and the fluctuation range. From these, it can be seen that there is a clear phase difference between the outlet 11 and the outlets A, B, and C. It can also be seen that there is a phase difference between the outlets.

The other conditions were the same as the above measurement, and only the flow rate ratio (F1: F2) was changed to 62:38, and the temporal change of the calorific value variation was measured. The results are shown in FIGS. Table 3 shows the time difference from the outlet 11 and the numerical value of the fluctuation range.

(Evaluation)
The results of the above test are summarized as shown in FIG. 9 when the relationship between the outlet position, the fluctuation range, and the phase time difference is summarized. For any flow rate ratio, the fluctuation width at the outlet C was the smallest, and the fluctuation phase difference with the outlet 11 was also the largest. On the other hand, the fluctuation range is larger than that at the outlet 11 at the outlet B position, and the phase difference is less likely to occur.
From the above results, it can be said that the phase difference that can cancel out the fluctuation range without exceeding the fluctuation range of the outlet 11 occurs in a range where L is 0.6 or more and less than 1.0. Further, the vicinity of L = 0.75 is considered as the optimum position.

Next, as shown in FIG. 10, instead of the test apparatus 1, the bypass pipe 5 is connected to the outlet C and the phase difference generating mechanism 21 (extension pipe = 38 m) is attached to the main pipe 4. A test apparatus 20 having a flow path difference between them was used. The calorimeter 8c was disposed on the downstream side of the junction 6. The same test as in Example 1 was performed with the flow ratio (F1: F2) set to 62:38. For comparison, a test was conducted in the case where no flow path difference was provided.
FIG. 11 shows an enlarged view of the temporal change of the calorific value fluctuation. When the flow path difference was provided, ΔH = 0.47 MJ / m 3, and the calorific value could be further stabilized as compared with the value when the flow path difference was not provided, 0.70 MJ / m 3.

  The present invention is widely used not only for suppressing the calorific value of fuel gas but also for suppressing the composition of a mixed gas composed of a plurality of gas components whose composition varies, such as raw material gas, by-product gas, exhaust gas, and produced gas by biomass in the chemical industry. Is possible.

1, 20 ··· Test device 2 ··· Container (adsorption tower)
4 ... Main piping 5 ... Bypass piping 7 ... Throttle valves 8a, 8b, 8c ... Calorimeter 9 ... Mass flow meter 10 ... Gas inlet 11 ... Gas outlet A, B, C ... Gas outlet

Claims (10)

A mixed gas supply apparatus comprising an adsorption tower filled with an adsorbent in a mixed gas supply line path whose gas composition changes over time,
The adsorption tower is
A gas inlet connected to the upstream piping of the supply line;
A gas outlet connected to the downstream piping of the supply line;
A gas extraction part at a predetermined position downstream from the middle of the gas inlet part and the gas outlet part,
On the downstream side of the adsorption tower, a bypass pipe connecting the gas extraction part and the junction of the downstream pipe,
In the path leading to the merging point downstream piping, and Ru ratio of the flow amount adjustment pollock of the mixed gas flow ratio control means for passing the downstream pipe and the bypass pipe,
The flow rate ratio adjustment of the flow amount ratio control means, the composition fluctuation range of the mixed gas after merging and repressible configured within the desired range, the mixed gas supply apparatus characterized by. Said predetermined position, the effective length of the adsorption tower (L), or 0.6 L, and mixed gas supply device according to claim 1, characterized in that the position of less than 1.0L . The mixed gas supply apparatus according to claim 1, wherein the predetermined position is a position in the vicinity of 0.75L with respect to the effective length (L) of the adsorption tower. In any one of Claims 1 thru | or 3 , The phase difference generation | occurrence | production means which produces | generates a phase difference in the composition fluctuation | variation of mixed gas based on a pipe flow path difference in at least one path | route of the said downstream piping or the said bypass piping, A mixed gas supply device, further comprising:   The mixed gas supply apparatus according to claim 4, wherein the phase difference generating means is an extension pipe of the downstream pipe or the bypass pipe. The mixed gas, mixed gas supply device according to any one of claims 1 to 5, characterized in that a fuel gas.   The mixed gas supply device according to claim 6, wherein the fuel gas is a city gas containing methane as a main component. The mixed gas supply apparatus according to any one of claims 1 to 7,
A composition fluctuation control method in a mixed gas supply apparatus, wherein the composition fluctuation of the mixed gas after merging is suppressed within a desired range by adjusting the flow ratio by the flow ratio control means. The mixed gas supply apparatus according to claim 6 or 7,
By adjusting the flow rate ratio of the fuel gas or city gas whose gas composition changes over time by the flow rate control means, the calorific value of the combined fuel gas or city gas is required by the Gas Business Law . A calorific value adjustment method in a mixed gas supply device, wherein the adjustment is performed within a range. 8. The mixed gas supply device according to claim 6 or 7, wherein the calorific value of the combined fuel gas or city gas can be adjusted within a predetermined range required by the Gas Business Law. A calorific value adjustment device.

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