Gas pretreatment equipment for gasification gas and gas pretreatment method

Abstract

To provide gas pretreatment equipment for gasification gas and a gas pretreatment method.SOLUTION: The equipment comprises: a gasification gas introduction line L1 for introducing gasification gas having an unsaturated hydrocarbon compound containing at least acetylene; a hydrogenation treatment device 13 equipped with a noble metal catalyst that hydrogenates gasification gas from the gasification gas introduction line to produce hydrogenated gas; a reforming furnace 16 that reforms the hydrogenated gas 14; and a reformed gas delivery line L4 that delivers reformed gas 14c reformed in the reforming furnace to the downstream side.SELECTED DRAWING: Figure 1A

Description

Technical Field

[0001] The present invention relates to gas pretreatment equipment for gasification gas and a gas pretreatment method.

Background Art

[0002] Conventionally, as a pre-process of a steam reforming apparatus, a hydrodesulfurization (hydrodesulfurization) reactor has been provided as equipment for removing sulfur components in raw material gas that act as catalyst poisons for the steam reforming catalyst (Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, when effectively using the gasification gas produced or generated by subjecting waste, biomass, etc. to partial oxidation treatment in a gasification furnace, when providing a hydrogenation (also referred to as "hydrogenation") reactor as a pretreatment of a reforming apparatus, if the gasification gas contains a large amount of unsaturated hydrocarbons such as ethylene, acetylene, propylene, butene, etc., a significant temperature rise occurs due to the heat generation by the hydrogenation (hydrogenation) reaction of the unsaturated hydrocarbons, deviating from the operating temperature range of the hydrogenation reactor, so there is a problem that it cannot be used as a raw material gas. Depending on the hydrogenation catalyst and reaction conditions used together, there is also a problem that a significant temperature rise occurs due to the hydrogenation (methanation) of carbon dioxide gas and carbon monoxide in the gasification gas.

[0005] 2 In addition, when the gasification gas contains a large amount of carbon monoxide (CO), on the reforming catalyst, carbon is deposited by the Boudouard reaction (2CO → CO

[0006] Moreover, among unsaturated hydrocarbons, acetylene in particular has high reactivity. In the case of a hydrogenation reaction at high temperature, heavy oil components resulting from the polymerization of acetylene are likely to be generated, which causes carbon deposition on the reforming catalyst and blocks the catalyst layer. When acetylene is introduced onto the reforming catalyst without hydrogenation treatment, there is also a problem that carbon deposition occurs on the reforming catalyst due to its high reactivity and the catalyst layer is blocked.

[0007] An object of the present invention is to provide a gas pretreatment facility and a gas pretreatment method for gasified gas that can effectively utilize, as a raw material gas for producing valuable substances, gasified gas having a high content of unsaturated compounds including acetylene.

Means for Solving the Problems

[0008] The gas pretreatment facility for gasified gas according to the first aspect of the present invention includes a gasified gas introduction line for introducing gasified gas having an unsaturated hydrocarbon compound containing at least acetylene, a hydrogenation treatment device equipped with a noble metal-based catalyst for hydrogenating the gasified gas from the gasified gas introduction line to obtain a hydrogenated treatment gas, a reforming furnace for reforming the hydrogenated treatment gas, and a reformed gas delivery line for delivering the reformed gas reformed in the reforming furnace to the downstream side, and is characterized by comprising these components.

[0009] The gas pretreatment method for gasified gas according to the second aspect of the present invention includes a hydrogenation treatment step of hydrogenating gasified gas having an unsaturated hydrocarbon compound containing acetylene discharged from a gasification facility with a noble metal-based catalyst to obtain a hydrogenated treatment gas, and a reforming step of reforming the hydrogenated treatment gas, and is characterized by comprising these steps.

Effects of the Invention

[0010] According to the present invention, the pretreatment of gasified gas containing acetylene generated from a gasification facility can be efficiently performed, and the pretreatment gas can be effectively utilized as a raw material gas for valuable substances.

Brief Description of the Drawings

[0011]

Fig. 1A

Fig. 1B

Fig. 2

Fig. 3

Fig. 4

Fig. 5

Mode for Carrying Out the Invention

[0012] Hereinafter, the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited by the following mode for carrying out the invention (hereinafter referred to as the embodiment). In addition, the constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art, substantially the same ones, and those within the so-called equivalent range. Furthermore, the constituent elements disclosed in the following embodiments can be combined as appropriate.

[0013] [Embodiment 1] FIG. 1A and FIG. 1B are schematic diagrams of a gas pretreatment device for gasification gas according to Embodiment 1. As shown in FIG. 1, the gas pretreatment device 100A-1 for gasification gas according to the present Embodiment 1 includes a gasification gas introduction line L for introducing a gasification gas (raw material gas) 12 having an unsaturated hydrocarbon containing at least acetylene 1 and a hydrogenation treatment device 13 that hydrogenates the gasification gas (raw material gas) 12 from the gasification gas introduction line L (hereinafter referred to as "hydrogenation treatment") to obtain a hydrogenated treatment gas, and a hydrogenated treatment gas supply line L for supplying the hydrogenated treatment gas (hereinafter referred to as "hydrogenated treatment gas") 14 from the hydrogenation treatment device 13 1 and a hydrogenated treatment gas supply line L 2 and a hydrogenated treatment gas supply line L 2is equipped with a booster 15 that is interposed and compresses the hydrogenation treatment gas 14, a reforming furnace 16 that reforms the compressed compressed gas 14b, and a reformed gas delivery line L that delivers the reformed gas 14c reformed in the reforming furnace 16 to the downstream side as a raw material gas for the valuable substance 17 4 and. In FIG. 1, reference numeral 20 denotes steam, 21 denotes a blower, and F denotes fuel (either oil or gas) supplied to the reforming furnace 16.

[0014] Here, as the gasified gas (raw material gas) 12 containing unsaturated compounds, in a gasification facility (not shown), it is a gasified gas obtained by subjecting a material to be treated such as biomass or waste to partial oxidation at a high temperature in a gasification furnace and removing halides such as chlorine and sulfur compounds. This gasified gas contains, for example, hydrogen (H 2 ), saturated hydrocarbons, unsaturated compounds (unsaturated hydrocarbons: for example, ethylene, acetylene, propylene, butene, etc.), carbon monoxide (CO), carbon dioxide (CO 2 ), nitrogen (N 2 ), argon (Ar), etc. Note that the content of unsaturated compounds in the raw material gas refers to those exceeding 1 DRYmol%, although it depends on the object to be gasified.

[0015] This gasified gas 12 is sent through a gasified gas introduction line L 1 to a hydrogenation treatment device 13 having a hydrogenation treatment catalyst, where the gasified gas 12 is hydrogenated.

[0016] If the inlet temperature of the hydrogenation treatment device 13 does not reach the predetermined catalyst setting temperature, a preheater such as an electric heater or a steam heater may be separately provided at the inlet side of the hydrogenation treatment device 13 as necessary.

[0017] Also, when a large amount of acetylene, which may explode when pressurized at a high concentration as an unsaturated compound in the raw material gas, is contained, when being reformed in the reforming furnace 16, since it is compressed by the booster 15, it is desirable to convert acetylene to ethylene or ethane in advance in the hydrogenation treatment device 13.

[0018] Here, examples of the hydrogenation catalyst of the hydrogenation treatment apparatus 13 include noble metal-based catalysts such as ruthenium (Ru), palladium (Pd), platinum (Pt), and rhodium (Rh), but the present invention is not limited thereto.

[0019] Here, as the hydrogenation catalyst, the catalytic reaction temperature of catalysts such as ruthenium (Ru), palladium (Pd), platinum (Pt), and rhodium (Rh) is preferably from room temperature to about 250°C, more preferably from 50°C to 220°C, and still more preferably from 150°C to 200°C. Note that the method of heating (temperature holding) the catalyst is not particularly limited.

[0020] This is because, in the case of a catalytic reaction exceeding 250°C, rapid heat generation due to the methanation of carbon dioxide gas or carbon monoxide occurs, and there is an increased possibility that highly reactive acetylenes polymerize to generate heavy oil components, which is not preferable.

[0021] The pressure in the catalytic reaction can be any pressure from atmospheric pressure to about 1 MPa, but it is preferably near atmospheric pressure. By using the noble metal-based catalyst in this way, it is possible to selectively hydrogenate acetylene while suppressing the generation of heavy oil components without causing rapid heat generation due to the methanation of carbon dioxide gas and carbon monoxide.

[0022] According to this embodiment, the concentration of acetylene (C 2 H 2 ) in the outlet gas of the hydrogenation treatment apparatus 13 is zero (below the detection limit), and the composition ratio of H 2 / CH 4 / CO 2 / CH 4 has the performance of being almost unchanged from the inlet of the hydrogenation treatment apparatus 13.

[0023] When a sulfur component or a halide component such as chlorine is present in the raw material gas 12, which is a gasification gas, it is preferable to use, as the raw material gas, a gas that has been previously adsorbed and removed, such as activated carbon modified with an active component or, for example, a NaO (sodium oxide) catalyst.

[0024] Alternatively, as shown in the gas pretreatment device 100A-2 of Fig. 1B, when sulfur components and chlorine components cannot be removed from the introduced raw material gas 12, it is preferable to install a desulfurization or dechlorination (halogenation) treatment device 18 for performing desulfurization treatment and dechlorination treatment before the hydrogenation treatment device 13 to remove them.

[0025] At this time, as shown in Fig. 1B, in the gas pretreatment device 100A-2, a measuring instrument 19 for measuring the components in the raw material gas 12 is provided in the gasification gas introduction line L 1 . And when it is determined in the measuring instrument 19 that there are sulfur components and chlorine components in the raw material gas 12, the switching valve V is switched to change the introduction of the raw material gas 12 from the gasification gas introduction line L 1A to the bypass line L 1B , and the desulfurization treatment or dechlorination treatment may be performed in the desulfurization or demineralization treatment device 18. Note that the desulfurization or demineralization pretreatment device 18 may perform only one of the desulfurization treatment or dechlorination (halogenation) treatment, or may perform the desulfurization treatment and dechlorination (halogenation) treatment simultaneously.

[0026] A booster 15 for compressing the hydrogenation treatment gas 14 is installed in the hydrogenation treatment gas supply line L 2 that sends the hydrogenation treatment gas 14 to the reforming furnace 16. Note that the installation of the booster 15 is not limited here.

[0027] The compressed gas 14b compressed by the booster 15 is sent to a reforming furnace 16 having a reforming catalyst for steam reforming, and is reformed here together with the steam 20 separately introduced. Here, as the reforming catalyst, a known reforming catalyst can be used. As the reforming catalyst, for example, Ni / Al 2 O 3 , Ni / MgOAl 2 O 3 , Ru / Al 2 O 3 and the like are exemplified, but the present invention is not limited thereto.

[0028] The steam reformed gas 14c reformed in the reformer 16 is delivered to the reformed gas delivery line L 4 The gas is then sent downstream as a raw material gas for valuable resources 17 via the gas separator 14. Here, as the reformer 16 of this embodiment, a steam reformer using steam is exemplified, but as another reforming device for reforming gas, for example, an autothermal reformer may be used.

[0029] In addition, acetylene, an unsaturated hydrocarbon, is a gas that may explode when pressurized at a high concentration and must be handled with care. However, by carrying out a hydrogenation reaction at a low pressure close to normal pressure before pressurizing with the booster 15, it is possible to hydrogenate unsaturated hydrocarbons containing, for example, acetylene.

[0030] <Test Example> The gas component is "H 2 / CO / CO 2 / CH 4 / C 2 H 4 / C 2 H 2 When a mixture of simulated gases of "C = 27.2 / 30.3 / 22.4 / 14.2 / 2.3 / 3.6%" was supplied, acetylene (C 2 H 2 A reaction test was conducted to hydrogenate . For the selective hydrogenation of acetylene in this test, a palladium (Pd) catalyst supported on a gamma alumina carrier was used (Test Example 1). As comparative catalysts, a Co-Mo based catalyst (Comparative Example 1) and a Ni-Mo based hydrodesulfurization catalyst (Comparative Example 2) were used. Here, as the catalyst in this test example 1, "Aeronite gAl-Pd005-sp2_4" (product name: manufactured by Itochu Ceratec Corporation) was used.

[0031] FIG. 5 shows the relationship between the temperature (°C) at the outlet of the catalyst layer in the catalytic reaction section of the test device and the outlet acetylene concentration (vol%). As shown in Fig. 5, in the Pd catalyst of Test Example 1, the catalyst reaction proceeded with almost no deterioration over time. In the low temperature range of 200 °C or lower, acetylene completely reacted, and no acetylene was detected at the outlet. There was no significant change in the other component ratios compared to the inlet.

[0032] On the other hand, in the Co-Mo catalyst of the comparative example (Comparative Example 1) and the Ni-Mo hydrodesulfurization catalyst (Comparative Example 2), no low temperature activity was observed, and acetylene completely reacted from around 300 °C or higher. However, in both catalysts, an oily component (presumably a heavy oil component) was generated, perhaps due to some polymerization of acetylene.

[0033] In contrast, no generation of liquid components was observed in the Pd catalyst of Test Example 1.

[0034] Regarding all the catalysts, no significant heat generation or increase in methane concentration was observed due to methanation.

[0035] In any of the catalysts, about 1% of C 4 compounds (for example, C 4 H 8 ) was generated. This is considered to be due to the reaction of acetylene with each other.

[0036] When these hydrogenated gases were introduced into the steam reforming reaction process, (using the same steam reforming catalyst for all), in the gas passing through the palladium (Pd) catalyst of Test Example 1, no deterioration of the reforming catalyst was observed and the reaction continued, and no deposition of carbon powder was observed.

[0037] On the other hand, in the catalyst passing gases of Comparative Examples 1 and 2, regardless of the presence or absence of acetylene, the pressure loss of the steam reforming catalyst increased within a few hours, and carbon powder was deposited on the steam reforming catalyst. As a result, it is speculated that acetylene and heavy oil components have an adverse effect on the reforming catalyst, but C4 compounds do not affect the steam reforming reaction.

[0038] As described above, when producing useful substances by performing steam reforming or the like on an acetylene-containing gas, by performing hydrogenation using a noble metal-based catalyst as a pretreatment process as in the present invention, it has been found that it leads to catalyst protection and extended life of the subsequent reforming process, and stable operation of the apparatus is expected.

[0039] [Embodiment 2] FIG. 2 is a schematic diagram of a gas pretreatment apparatus for gasification gas according to Embodiment 2. For the same configurations as those in Embodiment 1, the same reference numerals are given and duplicate explanations are omitted. The gas pretreatment apparatus 100B for gasification gas according to the present Embodiment 2 includes a recycle line L that recycles a part of the hydrogenated treatment gas (hereinafter referred to as "hydrogenated treatment gas") 14. 3-1 and the recycle line L 3-1 and a gas extraction line L that extracts a part 14a of the hydrogenated treatment gas 14 from the recycle line L. 3-2 This is for the case where the acetylene concentration in the raw material gas 12, which is gasification gas, increases more than expected and the temperature in the reactor 13 continues to rise above the set temperature due to the heat generation of the hydrogenation reaction. By circulating a part of the cooled hydrogenated treatment gas 14, it has the effect of keeping the inside of the reactor constant.

[0040] In the gas pretreatment apparatus 100B for gasification gas of the present embodiment, in the hydrogenation treatment apparatus 13, a recycle line L for recycling the hydrogenated treatment gas 14 is formed on the inlet side of the hydrogenation treatment apparatus 13. 3-1 This recycle line L 3-1 is provided with a heat exchanger 22, which exchanges heat between the gasification gas 12 in the gasification gas introduction line L 1 and the hydrogenated treatment gas 14. The hydrogenated treatment gas 14 after heat exchange is cooled by a cooler 23 to a predetermined temperature. The recycle ratio is desirably from 0 (no recycling) to 10 times.

[0041] [Embodiment 3] FIG. 3 is a schematic diagram of a gas pre-treatment apparatus for gasified gas according to Embodiment 3. For the same configurations as those in Embodiments 1 and 2, the same reference numerals are given and duplicate descriptions are omitted. The gas pre-treatment apparatus 100C for gasified gas according to the present Embodiment 3 is obtained by further installing a degassing line L in the gas pre-treatment apparatus 100B for gasified gas shown in FIG. 2 3―2 on the downstream side of the gas booster 15 of the gas, and is provided with a converter 30 having a reforming catalyst for reforming CO contained in the compressed gas 14b. Here, as the CO reforming catalyst, a known reforming catalyst can be used and is not limited. Here, as the reforming catalyst, an Fe-Cr catalyst can be exemplified, but the present invention is not limited thereto.

[0042] Here, when the CO concentration in the gas supplied to the steam reforming section is high, the Boudouard reaction (2CO → CO 2 + C) proceeds, carbon deposition occurs, and there is a problem that the activity of the steam reforming catalyst decreases or the catalyst layer is blocked.

[0043] As in the present embodiment, by disposing a CO converter (converter) 30 having a CO reforming catalyst on the downstream side of the booster 15 of the degassing line L 3-2 in front of the reforming furnace 16, the shift reaction (CO + H 2 O → CO 2 + H 2 ) is allowed to proceed to reduce the CO concentration (for example, reducing the CO concentration from 23 DRY mol% to 2 DRY mol%). After reducing the CO concentration in the compressed gas 14b introduced into the reforming furnace 16, by supplying it to the steam reforming catalyst, even a raw material gas 12 containing a high concentration of CO can be used as a raw material gas for steam reforming.

[0044] According to this embodiment, by mixing the gasification gas 12, which is a raw material gas containing a high concentration of unsaturated hydrocarbon and a high concentration of carbon monoxide, with the hydrogenation treatment gas 14, which is a recycle gas from the hydrogenation treatment apparatus 13, and sending the mixture back to the hydrogenation treatment apparatus 13 for hydrogenation, heat generation can be suppressed. Further, by reducing the CO concentration with the transformer 30, when reforming treatment is performed in the reforming furnace 16 thereafter, carbon is not deposited by the Boudouard reaction on the reforming catalyst, and cracking, pulverization, and activity reduction of the reforming catalyst, and blockage of the catalyst layer by the deposited carbon powder do not occur, and the steam reformed gas 14c can be stably obtained, and the raw material gas of the valuable substance 17 can be efficiently produced.

[0045] In addition, in the gas pretreatment apparatuses 100A-1 and 100A-2 for the gasification gas of Embodiment 1, a transformer may be installed in the same manner as in this embodiment.

[0046] [Embodiment 4] FIG. 4 is a schematic diagram of a gas pretreatment apparatus for a gasification gas according to Embodiment 4. For the same configurations as those in Embodiments 1 to 3, the same reference numerals are given, and duplicate explanations are omitted. The gas pretreatment apparatus 100D for a gasification gas according to this Embodiment 4 is the gas pretreatment apparatus 100C for a gasification gas shown in FIG. 3, and further, on the downstream side of the reforming furnace 16, a decarburization apparatus 31 for reducing the content of carbon dioxide (CO 2 ) in the reformed gas 14c is provided in the reformed gas delivery line L 4 .

[0047] In this embodiment, when removing carbon dioxide (CO 2 ), for example, a decarburization apparatus 31 for reducing the CO 2 gas concentration in the steam reformed gas 14c is installed.

[0048] As the decarburization apparatus 31, a carbon dioxide recovery apparatus including an absorption tower and a regeneration tower by the amine absorption method can be used. In addition, other than the amine absorption apparatus of the decarburization apparatus 31, a physical adsorption apparatus for dissolving CO 2 in a liquid and separating and recovering it, a CO 2A solid adsorption device that separates and recovers using a solid absorbent, CO 2 Examples include a membrane separation device that separates and recovers using a membrane having a separation function, but the present invention is not limited thereto.

[0049] In addition, for decarboxylation treatment, the "CO / CO 2 / H 2 ratio" of the steam reformed gas 14c is adjusted to an optimal concentration as the raw material gas of the valuable substance 17 used on the downstream side.

[0050] As described above, according to the present invention, by treating a gasification gas having a high concentration of unsaturated hydrocarbons and a high CO concentration, it is possible to perform pretreatment of the raw material gas of the valuable substance 17 in a general synthetic facility for chemical raw materials using oxogas or the like having CO and H 2 as the main components.

[0051] Examples of the valuable substance 17 include methanol, ethanol, acetic acid, polyurethane, synthetic oil, etc., but the present invention is not limited thereto.

[0052] In addition, in the gas pretreatment devices 100A-1 and 100A-2 of the gasification gas in Embodiment 1, a decarboxylation device 31 may be installed in the same manner as in the present embodiment.

Industrial Applicability

[0053] The present invention can be used for gas pretreatment facilities and gas pretreatment methods for pretreating the gasification gas discharged from a gasification furnace.

Explanation of Signs

[0054] 100A-1, 100A-2, 100B to 100D Gas pretreatment devices 12 Gasification gas 13 Hydrogenation treatment device 14 Hydrogenation treatment gas 14a Extracted hydrogenation treatment gas 14b Compressed gas 14c Steam reformed gas 15 Gas booster 16 Reformer 17 Valuable item 30 Transformer 31 Decarbonization device 32 Carbon dioxide gas L 1 Gasification gas introduction line L 2 Hydrogenation treatment gas supply line L 3-1 Recycling line L 3-2 Gas extraction line L 4 Reformed gas delivery line F Fuel

Claims

1. A gasification gas introduction line for introducing a gasification gas having an unsaturated hydrocarbon compound containing at least acetylene, A hydrogenation treatment device equipped with a noble metal-based catalyst for hydrogenating the gasification gas from the gasification gas introduction line to obtain a hydrogenated treatment gas, A reforming furnace for reforming the hydrogenated treatment gas, A reformed gas delivery line for delivering the reformed gas reformed in the reforming furnace to the downstream side, The gas pre-treatment equipment for gasification gas, characterized in that it is provided with the above.

2. A recycle line for recycling the hydrogenated treatment gas from the hydrogenation treatment device to the gasification gas introduction line, The gas pre-treatment equipment for gasification gas according to claim 1, characterized in that it is provided with a gas extraction line for extracting a part of the hydrogenated treatment gas from the recycle line.

3. The gas pre-treatment equipment for gasification gas according to claim 1 or 2, characterized in that a converter having a shift catalyst for shifting CO contained in the extracted hydrogenated treatment gas is provided on the upstream side of the reforming furnace.

4. The gas pre-treatment equipment for gasification gas according to claim 1 or 2, characterized in that a decarburization device for reducing the carbon dioxide content in the reformed gas is provided on the downstream side of the reforming furnace.

5. A hydrogenation treatment step of hydrogenating a gasification gas having an unsaturated hydrocarbon compound containing acetylene discharged from a gasification facility with a noble metal-based catalyst to obtain a hydrogenated treatment gas, A reforming step of reforming the hydrogenated treatment gas, The gas pre-treatment method for gasification gas, characterized in that it has the above.

6. A gas recycling step of recycling the hydrogenated treatment gas from the hydrogenation treatment step, A gas extraction step of extracting a part of the hydrogenated treatment gas from the recycling step and sending it to the reforming step, The gas pre-treatment method for gasification gas according to claim 5, characterized in that it has the above.

7. The gas pre-treatment method for gasification gas according to claim 5 or 6, characterized in that it has a CO shift step of shifting CO contained in the extracted hydrogenated treatment gas.

8. The gas pre-treatment method for gasification gas according to claim 5 or 6, characterized in that it has a decarburization step of reducing the carbon dioxide content in the reformed gas from the reforming step.

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