JP3943042B2 - Tar-containing gas cleaning method and apparatus, and combustible gas production method and apparatus - Google Patents

Description

〔実施例２〕
図１に示すフローに従って、タールおよびダストの洗浄・除去を行った。
【００７０】
表２に示すように、タール分は２００ｇ／Ｎｍ³であった。原料中のタール分が実施例１と異なる以外は、実施例１と同様の操作を行った。結果を表２に示す。
【００７１】
【表２】

〔実施例３〕
図１に示すフローに従って、タールおよびダストの洗浄・除去を行った。
【００７２】
表３に示すように、タール分は５ｇ／Ｎｍ³であった。原料中のタール分が実施例１と異なる以外は、実施例１と同様の操作を行った。結果を表３に示す。
【００７３】
【表３】

〔比較例〕
図２に示すフローに従って、タールおよびダストの洗浄・除去を行った。ガス化炉Ｃから得られたガス２１１（組成を表４に示す）を温度７００℃でボイラ２０１に供給し、温度２００℃まで冷却し、水スクラバー２０２に供給した。この２００℃のタール含有ガスは３５℃の循環水２１３と接触し、タールは凝縮し、ダストは捕集され、循環水２１２中に洗浄・除去された。循環水２１２はスクラバーポンプ２０３で固液分離器２０５に送られ、固形物（重質タールおよびダスト）２１５が分離された。固形物を除去した循環水は冷却器２０４へ送られ、スクラバー２０２の運転に必要な温度まで冷却され、補給用の洗浄水２１６と混合され、スクラバー２０２に供給された。運転を続けていたが、２４０時間後に冷却器２０４の差圧上昇が認められ、冷却器２０４の開放点検を行ったところ、熱交換用のチューブにタールの付着が確認された。これにより、長期間の運転は困難であることが推定された。表４に、製品ガス２１４の組成および固形物の組成を示す。
【００７４】
【表４】

実施例および比較例に示すように、２塔式の油スクラバーおよび水スクラバーの組み合わせによる実施例ではタール分、ダストを含むガスを連続処理することができたが、比較例に示すように１塔式スクラバーでは連続運転が困難であった。
【００７５】
【発明の効果】
本発明により、タールを含むガス中のタールを長期間連続して除去することのできるガス洗浄方法および装置が提供された。また、ゴミやバイオマス等の含炭素物質をガス化して可燃性ガスを長期間連続して製造できる方法および装置が提供された。
【図面の簡単な説明】
【図１】図１は、本発明の実施の一形態を示すフロー図である。
【図２】図２は、従来技術を説明するためのフロー図である。
【符号の説明】
Ａ：ガス化炉
Ｂ：タール含有ガス洗浄装置
Ｃ：ガス化炉
１：タール含有ガス
３：油スクラビングされたガス
４：製品ガス
１１：循環洗浄油
１７：固形物（重質タールおよびダスト）
１８：補給用洗浄油
２１：循環洗浄水
２６：排水
３３：軽質タール
１０１：水急冷装置
１０２：油スクラバー
１０３：油スクラバーポンプ
１０４：固液分離器
１０５：洗浄油タンク
１０６：洗浄油ポンプ
１０７：洗浄油冷却器
１０８：水スクラバー
１０９：油水分離器
１１１：軽質タールポンプ
１１２：洗浄水ポンプ
１１３：洗浄水冷却器[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a gas cleaning method for obtaining a gas having a small tar content by removing tar from a gas containing tar. The present invention also relates to a method for producing a gas containing hydrogen and carbon monoxide, which is useful as an industrial raw material or fuel, using garbage such as general waste and waste plastic, biomass, and the like as raw materials.
[0002]
[Prior art]
Garbage such as general waste and waste plastic has conventionally been treated by complete combustion. However, technologies for producing hydrogen and carbon monoxide from such garbage or biomass have been developed from the viewpoint of effective use of resources or to realize a recycling-oriented society.
[0003]
For example, in recent years, a high-temperature gasification and melting furnace method has been attracting attention, in which biomass or the like is partially burned or partially oxidized to generate a reducing gas containing a large amount of useful industrial raw materials such as hydrogen. In this gasification and melting furnace method, a method of generating heat with a temperature exceeding 1,000 ° C. and melting the produced ash and dust to reduce the volume of waste is performed. Furthermore, the use of reducing gas as another chemical raw material is also being realized.
[0004]
There is also a method of gasifying biomass or the like by pyrolysis.
[0005]
In either case, a flammable gas is obtained. This gas contains tar, dust, and the like in addition to industrially useful components such as hydrogen, carbon monoxide, and hydrocarbons. When such a gas is used as an industrial raw material or fuel, the continuous operation of a chemical plant or a combustion apparatus may be hindered by tar or the like. For this reason, conventionally, tar and the like have been removed from the gas.
[0006]
Conventionally, tar and the like have been removed by using a one-column cleaning apparatus that performs cleaning with cleaning water as shown in FIG. In the single tower type cleaning apparatus, the gas 211 containing tar supplied to the scrubber 202 is cleaned using circulating cleaning water 213. In addition, a cooler (heat exchanger) 204 is installed to cool the wash water.
[0007]
In such a conventional technique, a viscous emulsion is formed in the wash water (circulated water) 212 in which the tar contained in the gas 211 is circulated, and may adhere to the tube or shell of the cooler 204. In addition, the dust in the gas 211 may be supplemented by the emulsion in the circulating water 212. As a result, the heat exchange capacity is reduced, or the tube is blocked, making it difficult to continuously operate the cleaning device. There was a case.
[0008]
Further, not only in the cooler but also in other parts, a phenomenon such as blockage of the flow path may occur due to condensation or adhesion of tar or the like.
[0009]
As a technique related to gas cleaning as described above, Patent Document 1 discloses a method of purifying gas by washing a gas containing dust and tar with water and filtering the dust and tar together from water. Yes.
[0010]
Further, Patent Document 2 discloses a method for decomposing a tar content contained in a gas by raising the temperature and removing the tar content from the gas.
[0011]
In addition, Patent Document 3 discloses a method of removing tar and dust in the gas by spraying the tar recovered from the gas. This method is characterized in that tar and dust are recovered by the tar content recovered from the gas, and at the same time, heat exchange is performed to lower the temperature of the gas.
[0012]
[Patent Document 1]
JP-A-11-57656
[Patent Document 2]
JP-A-7-324716
[Patent Document 3]
JP 56-106992 A
[0013]
[Problems to be solved by the invention]
The objective of this invention is providing the gas cleaning method and apparatus which can remove the tar in the gas containing tar continuously for a long period of time.
[0014]
Another object of the present invention is to provide a method and apparatus capable of gasifying garbage and biomass and continuously producing a combustible gas for a long period of time.
[0015]
[Means for Solving the Problems]
  According to the present invention, tarAnd dustIn the tar-containing gas cleaning method for reducing the tar content in the tar-containing gas containing
An oil scrubbing step for scrubbing the tar-containing gas with cleaning oil;
A water scrubbing step for scrubbing the tar-containing gas that has undergone the oil scrubbing step with cleaning water;,
A tar and dust separation step for separating tar and dust from the cleaning oil obtained from the oil scrubbing step;
Circulating the cleaning oil obtained from the tar and dust separation step to the oil scrubbing step;
A method for cleaning tar-containing gas is provided.
[0016]
In this method, among the tars contained in the tar-containing gas,
Separating heavy tar having a relatively high boiling point from the tar-containing gas by the oil scrubbing;
Separating light tar having a relatively low boiling point from the tar-containing gas by the water scrubbing;
It is preferable.
[0017]
Moreover, it is also preferable to use the light tar separated by the water scrubbing as a cleaning oil in the oil scrubbing step.
[0018]
  According to the present invention, in a combustible gas production method for producing a combustible gas containing hydrogen and carbon monoxide by gasifying a gasification raw material,
Gasification of gasification raw material, tar in addition to hydrogen and carbon monoxideAnd dustA gasification step for producing a tar-containing combustible gas containing,
An oil scrubbing step for scrubbing the tar-containing combustible gas with a cleaning oil;
A water scrubbing step for scrubbing tar-containing combustible gas that has undergone the oil scrubbing step with cleaning water;,
A tar and dust separation step for separating tar and dust from the cleaning oil obtained from the oil scrubbing step;
Circulating the cleaning oil obtained from the tar and dust separation step to the oil scrubbing step;
A method for producing a combustible gas is provided.
[0019]
  According to the present invention, tarAnd dustIn the tar-containing gas cleaning device for reducing the tar content in the tar-containing gas containing
An oil scrubber for scrubbing the tar-containing gas with a cleaning oil;
A water scrubber for scrubbing tar-containing gas discharged from the oil scrubber with cleaning water;,
A solid-liquid separator for separating tar and dust from the cleaning oil discharged from the oil scrubber;
A cleaning oil circulation line for circulating the cleaning oil from which tar and dust have been separated by the solid-liquid separator to the oil scrubber;
A tar-containing gas cleaning apparatus is provided.
[0020]
  In this device, furtherThe aboveThe cleaning oil circulation line is provided with cleaning oil cooling means for cooling the cleaning oil, and
To separate tar from the wash water discharged from the water scrubberNoA tool separating means,TheA washing water circulation line for circulating the washing water from which tar has been separated by the water separation means to the water scrubber, and the washing water circulation means is provided with washing water cooling means for cooling the washing water
It is preferable.
[0021]
  Furthermore, beforeWritingIt is preferable to have means for supplying the tar separated by the tool separation means to the oil scrubber as cleaning oil.
[0022]
  According to the present invention, in a combustible gas production apparatus for producing a combustible gas containing hydrogen and carbon monoxide by gasifying a gasification raw material,
Gasification of gasification raw material, tar in addition to hydrogen and carbon monoxideAnd dustA gasifier for producing a tar-containing combustible gas containing,
An oil scrubber for scrubbing the tar-containing combustible gas with a cleaning oil;
A water scrubber for scrubbing tar-containing combustible gas discharged from the oil scrubber with cleaning water;,
A solid-liquid separator for separating tar and dust from the cleaning oil discharged from the oil scrubber;
A cleaning oil circulation line for circulating the cleaning oil from which tar and dust have been separated by the solid-liquid separator to the oil scrubber;
There is provided a combustible gas production apparatus characterized by comprising:
[0023]
DETAILED DESCRIPTION OF THE INVENTION
The inventors consider the nature of the tar with respect to the removal of the tar, and the relatively heavy tar of the tar is washed and removed with an appropriate hydrocarbon-based washing oil to remove the heavy tar. The method of washing and removing the light tar with water was found to be an effective means for solving the above problems, and the present invention was completed.
[0024]
As a gasification raw material that is a raw material for producing a combustible gas, a conventionally known raw material can be used as a raw material from which a gas containing hydrogen and carbon monoxide can be obtained by gasification. Examples of the gasification raw material include carbon-containing substances that are solid or liquid at normal temperature and normal pressure (25 ° C., 0.10 MPa), such as waste, biomass, coal, and heavy oil. These raw materials can be used in combination of a plurality of types.
[0025]
As the waste, for example, general waste (combustible material) such as household waste and business waste, and industrial waste (combustible material) such as waste plastic and waste oil can be used. Biomass is a biological organic resource, and for example, wood (wood waste), agricultural products (agricultural waste), algae, plankton, and biological waste can be used. In addition, low grade coal, RDF (solidified fuel), and the like can also be used as gasification raw materials.
[0026]
The composition of the combustible gas containing hydrogen and carbon monoxide obtained by gasification varies depending on the gasification raw material, gasification conditions, and the like, and depends on the use of the combustible gas, and is not particularly limited in the present invention. For example, a combustible gas containing 10 to 50 mol% of hydrogen (dry base) and 5 to 25 mol% of carbon monoxide (dry base) can be obtained by biomass gasification.
[0027]
As a gasification method, as disclosed in Patent Document 1, a gasification raw material is heated to 300 to 600 ° C. while shutting off air to generate a pyrolysis gas that is a combustible gas containing tar and dust. Or pyrolysis pyrolysis. As this apparatus, a rotary pyrolysis drum as disclosed in Patent Document 1 can be used.
[0028]
In addition to this, the amount of oxidant (air or oxygen) during combustion can be reduced from the amount necessary for complete combustion to obtain a combustible gas in an incomplete combustion state. As an apparatus for this purpose, an apparatus capable of adjusting the amount of oxidant sent to the combustion apparatus in an apparatus for burning waste can be realized.
[0029]
Tar is, for example, a brownish or black liquid material that has a high viscosity at room temperature and normal pressure, which is generated by thermal decomposition of organic matter, and includes aromatic hydrocarbons as the main component, and also includes compounds containing oxygen, nitrogen, or sulfur. is there. Each component of tar differs in production amount and composition depending on the raw material of gasification gas, gasifier operating temperature, type of gasifier, and gasifier operation method (using oxygen, using air, etc.) ing.
[0030]
When the gasification raw material is gasified, at least CO and H₂Gas containing and tar is generated. The generated tar is vaporized according to the heat applied in the gasification furnace. And the gas discharged from the gasifier is CO or H₂In addition to the tar content depending on the temperature. Industrially, this gas often accompanies dust. Examples of the dust include ash, char (carbon), and sand (silica sand) used as a fluid medium in a combustion furnace. The gas containing at least hydrogen, carbon monoxide and tar obtained in this way is referred to herein as a tar-containing combustible gas.
[0031]
Although the tar-containing combustible gas can be cleaned by the cleaning method of the present invention, the present invention is not limited thereto, and any gas containing tar (tar-containing gas) can be cleaned by the cleaning method of the present invention. . It may contain dust in addition to tar.
[0032]
As the tar-containing gas that can be suitably cleaned according to the present invention, from the viewpoint of suppressing the remaining amount of tar and dust in the product gas, the tar is 200 g / Nm.^ThreeOr less, preferably 150 g / Nm^ThreeMore preferably, the dust content is 20 g / Nm.^ThreePreferably, it is 10 g / Nm or less.^ThreeThe following is more preferable. Tar is preferably 3 g / Nm.^ThreeOr more, more preferably 5 g / Nm^ThreeFor the gas described above, the effects of the present invention can be exhibited particularly remarkably. When the tar-containing gas contains dust, the dust is preferably 3 g / Nm.^ThreeOr more, more preferably 4 g / Nm^ThreeFor the gas described above, the effects of the present invention can be exhibited particularly remarkably. Nm^ThreeIs cubic meter at 0 ° C. and 0.101 MPa (m^Three).
[0033]
Scrubbing is to remove the impurities by bringing the liquid into contact with gas by spraying or the like, and the scrubber is a device for scrubbing. Scrubbing itself is a known technique and is widely applied to the purification of various exhaust gases. Oil (cleaning oil) is used as this liquid in oil scrubbing, and water (washing water) is used in water scrubbing.
[0034]
As cleaning oil, oil that is liquid at the operating temperature of the oil scrubber can be used. For example, light oil, kerosene, and components from petroleum refining equipment as defined in JIS (Japanese Industrial Standards) can be used. Is possible.
From the viewpoint of the tar removal rate, it is preferable that the tar content is easily dissolved in the cleaning oil. It is also preferable that handling is easy. From the viewpoint of suppressing the mixing of the cleaning oil into the gas, the vapor pressure is preferably as low as possible at the operating temperature of the oil scrubber. An example of such oil is LCO (Light Cycle Oil: equivalent to light oil).
[0035]
As the washing water, water such as industrial water or city water can be used. Further, as will be described later, additives may be added as necessary, such as adding alkali to water for removing chlorine.
[0036]
The operating temperature of the oil scrubber varies depending on the operating pressure, but the operating temperature of the oil scrubber must be higher than the operating temperature of the water scrubber in order to achieve the effect of scrubbing gas in two stages of oil scrubbing and water scrubbing. Is preferred. The operating temperature of the water scrubber is determined in consideration of the product gas specifications. The lower the operating temperature of the water scrubber, the lower the content of cleaning oil and tar in the product gas. In addition, the operating temperature of the water scrubber is strongly influenced by the temperature of the cleaning water supplied to the water scrubber, and when determining the operating temperature of the water scrubber, the economy related to the temperature management of the cleaning water is also taken into consideration. The washing water is cooled by the cooling water in the cooler 113. This cooling water is preferably circulated and reused, and the circulated wash water can be cooled using a cooling tower widely used in industry. Since a general cooling tower uses air to cool, the temperature of the cooling water is affected by the air temperature, but is usually selected in the range of 30 ° C to 50 ° C. Since the cleaning water is cooled by this cooling water, the temperature of the cleaning water is set to, for example, 35 ° C. to 60 ° C. in consideration of economy. By setting the temperature of the cleaning water supplied to the water scrubber to 60 ° C. or less, the content of tar and cleaning oil in the product gas can be kept low. Furthermore, the content of tar and cleaning oil in the product gas can be further reduced by lowering the temperature of the cleaning water using a refrigerant device.
[0037]
For example, the operating temperature of the oil scrubber can be selected in the range of 100 ° C to 200 ° C, and the operating temperature of the water scrubber can be selected in the range of 40 ° C to 60 ° C.
[0038]
By the way, the gas obtained by gasification often contains moisture. When water is contained in the tar-containing gas, it is preferable to avoid condensation of water in the oil scrubber. This avoids the formation of water-tar emulsions in the cleaning oil, can greatly reduce the possibility of clogging of pipes, etc., due to the emulsion, and the tar vapor pressure is lowered, making tar difficult to condense. Can be avoided. For this purpose, the operating temperature of the oil scrubber may be set higher than the condensation temperature of water at the operating pressure of the oil scrubber. On the other hand, when the operating temperature of the oil scrubber increases, tar that can be removed in the oil scrubber decreases, the load of the water scrubber installed in the subsequent stage increases, the size of the entire apparatus tends to increase, and the economy tends to decrease. . Considering the above points, and from the viewpoint of operational stability, the operating temperature of the oil scrubber is preferably set to a temperature 30 ° C. to 40 ° C. higher than the water condensation temperature at the operating pressure of the oil scrubber. Considering the case where the operating pressure of the oil scrubber is atmospheric pressure (0.10 MPa) as an example, considering the partial pressure, 80 ° C. to 90 ° C. is the water condensing temperature, so the range of 30 ° C. to 40 ° C. is considered. The operating pressure of the oil scrubber is preferably set to 110 to 130 ° C, for example, about 120 ° C.
[0039]
About one form of the combustible gas manufacturing apparatus of this invention, a process flow is shown in FIG. This apparatus has a gasification furnace A and a tar-containing gas cleaning apparatus B.
[0040]
The gasifier A adds carbon-containing substances, which are raw materials for combustible gas production, to tar and dust in addition to industrially effective components such as hydrogen, carbon monoxide, and hydrocarbons (methane, ethane, ethylene, etc.). The tar-containing gas 1 is contained.
[0041]
The tar-containing gas scrubber B is an oil scrubber 102 that removes a component having a relatively high boiling point (heavy tar) from the tar in the tar-containing gas 1, and a relative gas contained in the gas 3 purified by the oil scrubber. The water scrubber 108 removes a component having a low boiling point (light tar).
[0042]
The oil scrubber 102 is connected to a solid-liquid separator 104 that separates heavy tar contained in the gas 3 from the cleaning oil 12 together with dust. The water scrubber 108 separates light tar from the cleaning water 22. An oil / water separator 109 for cooling and a cooler 113 for cooling circulating wash water are connected. In addition, an oil scrubber pump 103 for boosting the cleaning oil discharged from the oil scrubber as needed, a cleaning oil tank 105 provided downstream of the solid-liquid separator 104, and a cleaning oil from the cleaning oil tank to the oil scrubber The cleaning oil pump 106 for performing the cleaning, the light tar pump 111 for boosting the light tar discharged from the oil / water separator, and the cleaning water pump 112 for circulating the cleaning water are installed. A heat exchanger such as a multi-tube cylindrical heat exchanger can be used for the wash water cooler, and a pump such as a centrifugal pump can be used as the wash water pump.
[0043]
One embodiment of the present invention will be described in more detail with reference to FIG.
[0044]
First, the high-temperature tar-containing combustible gas 1 including tar and dust in addition to hydrogen and carbon monoxide is appropriately adjusted to an operating temperature of the oil scrubber 102 and introduced into the oil scrubber 102.
[0045]
When the gas 1 contains a component that may regenerate dioxin, it is preferable to install a water quenching apparatus 101 having a quenching function in order to avoid the regeneration of dioxin for the temperature adjustment. . If there is no problem of dioxin regeneration, consider the effective use of the entire heat, install a boiler instead of a water quenching device, generate steam by sensible heat of gas 1 and recover heat, Alternatively, a heat exchanger can be provided to heat another fluid by sensible heat of the gas 1.
[0046]
The temperature-controlled gas 2 is supplied to the oil scrubber 102 at a temperature of about 200 ° C., for example. The temperature of the gas 2 supplied to the oil scrubber 102 may be appropriately determined depending on the properties of the tar to be generated within a range where the tar in the gas 2 is not condensed.
[0047]
In the oil scrubber, dust and heavy tar are mainly removed from the gas 2. In order to remove the tar content, an appropriate cleaning oil may be selected in consideration of the physical properties of the cleaning oil.
[0048]
In the oil scrubber, among the tars contained in the gas 2, heavy tar which is a tar having a boiling point equal to or higher than the operating temperature of the oil scrubber is separated from the cleaning oil, and the cleaning oil 12 containing the heavy tar is discharged from the scrubber. . At this time, the dust is separated together with the heavy tar. On the other hand, light tar, which is a tar having a boiling point lower than the operating temperature of the oil scrubber, remains in the oil scrubbed gas 3.
[0049]
A gas-liquid contact device can be used for the oil scrubber. Basically, the liquid is supplied from vertically upward to downward, but the gas in contact with the liquid is countercurrent or cocurrent to the liquid flow. Either of these may be used. As the gas-liquid contact device, for example, a packed tower filled with a packing so as to improve contact between gas and liquid, or a shelf tower provided with a shelf can be used. As the shelf, a shelf that is difficult to block with tar or dust, for example, a perforated plate is preferable, and in this case, the flow form is preferably cocurrent. As a suitable shelf, for example, a tray shown in Japanese Patent No. 3061750 called a swing tray can be cited.
[0050]
For example, the gas 2 whose temperature is controlled to 200 ° C. comes into contact with the circulating cleaning oil 11 whose temperature is controlled to 40 ° C., for example, is cooled, heavy tar is condensed, dust is collected, and heavy tar and dust are contained. The circulating cleaning oil 12 is extracted from the lower part of the oil scrubber 102 by the oil scrubber pump 103, and the heavy tar and dust 17 are separated from the cleaning oil 13 whose pressure has been increased by the pump by the solid-liquid separator 104.
[0051]
The solid-liquid separator separates solids and liquids, and the type of the solid-liquid separator is not particularly limited, but here a cyclone is used. Here, the dust is separated as a solid in a form containing heavy tar, but the solid contains oil (tar), and thus can be used as appropriate. As one of its utilization methods, it can be considered that it is used for combustion in a combustion furnace or the like together with other combustible solids.
[0052]
The circulating cleaning oil 14 from which heavy tar and dust have been removed by the solid-liquid separator 104 is sent to a cleaning oil tank 105, where it is mixed with the cleaning oil 18 for replenishment, passes through a line 15, and passes through a cleaning oil pump 106. The pressure of the cleaning oil 16 is increased by the pressure, and is sent to the cleaning oil cooler 107, is appropriately cooled to an appropriate temperature with cooling water, is sent again to the oil scrubber 102, and is used as cleaning oil.
[0053]
The temperature of the circulating cleaning oil 11 may be determined in consideration of the operating temperature of the oil scrubber 102 and the physical properties of the circulating cleaning oil 11. When LCO is used as the cleaning oil, a temperature of about 120 ° C. is preferably selected. When another type of cleaning oil is selected as the cleaning oil, the operating condition of the oil scrubber can be selected in consideration of the properties of the selected cleaning oil.
[0054]
The gas 3 exiting from the oil scrubber 102 from which most of the tar and dust have been removed is supplied to the water scrubber 108 and scrubbed by the wash water 21 to remove the light tar contained in the gas. Become.
[0055]
The amount of dust in the product gas is, for example, 10 mg / Nm when the product gas is used as a fuel for a gas turbine or the like.^ThreeHereinafter, when using product gas as a raw material for chemical synthesis, 0.02 mg / Nm^ThreeThe following is preferable. However, it is not necessary to reduce the amount of dust in the product gas to the above range by oil and water scrubbing. Oil and water scrubbing can reduce the amount of dust in the gas to a range suitable for processing with a bag filter or electrostatic precipitator, and then the amount of dust can be made within the above range with a bag filter or electrostatic precipitator.
[0056]
The amount of tar in the product gas is, for example, 50 mg / Nm when the product gas is used as a fuel for a gas turbine or the like.^ThreeHereinafter, 0.1 mg / Nm when product gas is used as a raw material for chemical synthesis^ThreeThe following is preferable.
[0057]
As the water scrubber 108, a gas-liquid contact device can be used. Basically, the liquid is supplied from vertically upward to downward, but the gas in contact with the liquid is countercurrent or parallel to the liquid flow. Any of the flow may be used. As the gas-liquid contact device, for example, a packed tower filled with a packing so as to improve the contact between gas and liquid can be used, but a shelf tower provided with a shelf can also be used. Examples of the filler include Raschig rings, Lessing rings, Berle saddles, Interlocks saddles, terralet, ball rings, and the like.
[0058]
Wash water 22 containing light tar is separated into light tar 31 and wash water 23 by an oil / water separator 109, and a part 26 of the wash water 23 is discharged out of the system as necessary, and the remaining wash. The water 24 is pressurized by the washing water pump 112. The pressurized washing water 25 is sent to the cooler 113, the temperature of which is adjusted, and the washing water 21 is supplied to the water scrubber.
[0059]
For example, when waste containing chloride is gasified as a raw material, the tar-containing gas 1 obtained by gasification may contain chloride. When a product gas containing chloride is used as an industrial raw material and a catalytic reaction is performed, the catalyst may be poisoned. In this way, when the tar-containing gas 1 contains impurities that cause problems when using the product gas, the water scrubber 108 can treat the impurities. If the impurity is chloride, it can be neutralized using, for example, an alkali as an absorbent. Specifically, alkaline washing water can be used. Further, when a crystalline substance is generated by this neutralization method, a solid-liquid separator is provided downstream of the oil-water separator 109 (for example, between the oil-water separator and the washing water pump 112) to separate the crystalline substance. The liquid part can be sent to a water scrubber.
[0060]
The product gas contains a part of the cleaning oil and a part of the light tar. The water scrubber 108 is operated so that the allowable values of these components are satisfied in consideration of the specifications of the product gas. The temperature can be determined. When the operating temperature of the water scrubber 108 is increased, the concentration of the cleaning oil and light tar contained in the product gas is increased, and when the temperature is decreased, the concentration of the cleaning oil and light tar included in the product gas is decreased.
[0061]
As the oil-water separator 109, for example, an oil-water separator having a specific gravity can be used to separate light tar and water. The separated light tar 31 can be used for the cleaning oil 11 of the oil scrubber 102 (in this case, the lines 32 and 34 are used), or may be extracted out of the system and used for fuel or the like. (At this time, lines 32 and 33 are used).
[0062]
From the viewpoint of ease of handling, the heavy tar and dust 17 may be mixed with a part of the cleaning oil circulated using, for example, the line 19 to make it liquid. In addition, a heat exchanger 120 that adjusts the temperature of the heavy tar and dust 17 may be provided for viscosity adjustment and the like.
[0063]
【Example】
Hereinafter, the present invention will be described in more detail based on examples.
[0064]
[Example 1]
Tar and dust were washed and removed according to the flow shown in FIG. As shown in Table 1, the tar content in the tar-containing gas is 20 g / Nm.^ThreeMet.
[0065]
Gas 1 having the composition shown in Table 1 obtained by gasifying biomass with a gasification melting furnace is supplied to water quenching apparatus 101 at a temperature of 700 ° C., and quenching water is supplied to oil scrubber 102 at a supply temperature of 200 ° C. It was quickly cooled at This gas 2 at 200 ° C. is washed with the circulating cleaning oil 11 at 40 ° C. in the oil scrubber 102, cooled to 120 ° C. which is the operating temperature of the oil scrubber, and heavy tar (boiling point of 120 ° C. or higher) in the gas. Tar) was condensed and discharged together with dust from line 12 at 120 ° C. and sent to solid-liquid separator 104 by oil scrubber pump 103 to separate solid matter 17 (heavy tar and dust). The circulating cleaning oil 14 separated from the solid matter is sent to the cleaning oil tank 105, mixed with the newly supplied cleaning oil 18, passed through the line 15, and sent to the cleaning oil cooler 107 by the cleaning oil pump 106. The temperature was adjusted to 40 ° C. and circulated through the oil scrubber 102. The cleaning oil was LCO (Light Cycle Oil: equivalent to light oil) for ease of handling. Table 1 shows the LCO cleaning oil supply conditions.
[0066]
The gas 3 at 120 ° C. from which dust and heavy tar were separated was supplied to the water scrubber 108. In the water scrubber 108, the gas 3 was brought into contact with the circulating washing water 21 at 35 ° C. and cooled to 40 ° C., which is the operating temperature of the water scrubber, and the light tar in the gas 3 was removed to the line 22 at 40 ° C. The gas 4 at 40 ° C. from which the light tar had been removed became a product gas and was led out of the system. Table 1 shows the conditions of the product gas 4.
[0067]
The circulating wash water 22 containing light tar from the lower part of the water scrubber 108 was supplied to the oil / water separator 109 and separated into the light tar 31 and the circulating wash water 23. The separated light tar was led out of the system as light tar 33. In addition, a part of the circulating cleaning water 23 was discharged out of the system as drainage 26, and appropriate treatment was performed. Table 1 shows the conditions of the light tar 33 and the drainage 26.
[0068]
When processed with the gas processing apparatus of the present invention, the dust and tar concentrations in the product gas were as shown in Table 1.
[0069]
[Table 1]

[Example 2]
Tar and dust were washed and removed according to the flow shown in FIG.
[0070]
As shown in Table 2, the tar content is 200 g / Nm.^ThreeMet. The same operation as in Example 1 was performed except that the tar content in the raw material was different from that in Example 1. The results are shown in Table 2.
[0071]
[Table 2]

Example 3
Tar and dust were washed and removed according to the flow shown in FIG.
[0072]
As shown in Table 3, the tar content is 5 g / Nm.^ThreeMet. The same operation as in Example 1 was performed except that the tar content in the raw material was different from that in Example 1. The results are shown in Table 3.
[0073]
[Table 3]

[Comparative Example]
Tar and dust were washed and removed according to the flow shown in FIG. A gas 211 (composition shown in Table 4) obtained from the gasification furnace C was supplied to the boiler 201 at a temperature of 700 ° C., cooled to a temperature of 200 ° C., and supplied to the water scrubber 202. This 200 ° C. tar-containing gas contacted with the 35 ° C. circulating water 213, the tar was condensed, the dust was collected, washed and removed in the circulating water 212. The circulating water 212 was sent to the solid-liquid separator 205 by the scrubber pump 203, and the solids (heavy tar and dust) 215 were separated. The circulating water from which the solid matter was removed was sent to the cooler 204, cooled to a temperature necessary for the operation of the scrubber 202, mixed with the cleaning water 216 for replenishment, and supplied to the scrubber 202. Although the operation was continued, an increase in the differential pressure of the cooler 204 was observed after 240 hours, and when the open check of the cooler 204 was performed, adhesion of tar was confirmed on the heat exchange tube. As a result, it was estimated that long-term operation was difficult. Table 4 shows the composition of the product gas 214 and the composition of the solid material.
[0074]
[Table 4]

As shown in the examples and comparative examples, in the examples using a combination of a two-column type oil scrubber and a water scrubber, a gas containing tar and dust could be continuously treated. Continuous operation was difficult with the type scrubber.
[0075]
【The invention's effect】
According to the present invention, a gas cleaning method and apparatus capable of continuously removing tar in a gas containing tar for a long period of time have been provided. In addition, a method and apparatus have been provided that can gasify carbon-containing substances such as garbage and biomass to produce a combustible gas continuously for a long period of time.
[Brief description of the drawings]
FIG. 1 is a flowchart showing an embodiment of the present invention.
FIG. 2 is a flowchart for explaining the prior art.
[Explanation of symbols]
A: Gasification furnace
B: Tar-containing gas cleaning device
C: Gasification furnace
1: Tar-containing gas
3: Oil scrubbed gas
4: Product gas
11: Circulating cleaning oil
17: Solid (heavy tar and dust)
18: Cleaning oil for replenishment
21: Circulating wash water
26: Drainage
33: Light tar
101: Water quenching device
102: Oil scrubber
103: Oil scrubber pump
104: Solid-liquid separator
105: Cleaning oil tank
106: Cleaning oil pump
107: Cleaning oil cooler
108: Water scrubber
109: Oil-water separator
111: Light tar pump
112: Wash water pump
113: Wash water cooler

Claims (8)

In the method for cleaning a tar-containing gas that reduces the tar content in the tar-containing gas containing tar and dust ,
An oil scrubbing step for scrubbing the tar-containing gas with cleaning oil;
A water scrubbing step for scrubbing the tar-containing gas that has undergone the oil scrubbing step with cleaning water ;
A tar and dust separation step for separating tar and dust from the cleaning oil obtained from the oil scrubbing step;
And a step of circulating the cleaning oil obtained from the tar and dust separation step to the oil scrubbing step . Of the tars contained in the tar-containing gas,
Separating heavy tar having a relatively high boiling point from the tar-containing gas by the oil scrubbing;
Separating light tar having a relatively low boiling point from the tar-containing gas by the water scrubbing;
The method of claim 1.   The method according to claim 2, wherein the light tar separated by the water scrubbing is used as a cleaning oil in the oil scrubbing step. In a combustible gas production method for producing a combustible gas containing hydrogen and carbon monoxide by gasifying a gasification raw material,
A gasification step of gasifying the gasification raw material to produce a tar-containing combustible gas containing tar and dust in addition to hydrogen and carbon monoxide;
An oil scrubbing step for scrubbing the tar-containing combustible gas with a cleaning oil;
A water scrubbing process for scrubbing the tar-containing combustible gas that has undergone the oil scrubbing process with cleaning water ;
A tar and dust separation step for separating tar and dust from the cleaning oil obtained from the oil scrubbing step;
And a step of circulating the cleaning oil obtained from the tar and dust separation step to the oil scrubbing step . In the tar-containing gas cleaning device for reducing the tar content in the tar-containing gas containing tar and dust ,
An oil scrubber for scrubbing the tar-containing gas with a cleaning oil;
A water scrubber for scrubbing the tar-containing gas discharged from the oil scrubber with scrubbing water ;
A solid-liquid separator for separating tar and dust from the cleaning oil discharged from the oil scrubber;
A cleaning apparatus for tar-containing gas, comprising: a cleaning oil circulation line for circulating cleaning oil from which tar and dust have been separated by the solid-liquid separator to the oil scrubber . In addition ,
The cleaning oil circulation line is provided with cleaning oil cooling means for cooling the cleaning oil, and
Yes and data Lumpur separating means for separating the tar from the wash water discharged from the water scrubber, a washing water circulation line that circulates the washing water tar is separated to the water scrubber through 該Ta Lumpur separating means 6. The apparatus according to claim 5, wherein the washing water circulation line is provided with washing water cooling means for cooling the washing water. Further, before the tar separated by Northern Lumpur separator apparatus of claim 6, further comprising a means for supplying a cleaning fluid to the oil scrubber. In a combustible gas production apparatus for producing a combustible gas containing hydrogen and carbon monoxide by gasifying a gasification raw material,
A gasifier that gasifies a gasification raw material to produce a tar-containing combustible gas containing tar and dust in addition to hydrogen and carbon monoxide;
An oil scrubber for scrubbing the tar-containing combustible gas with a cleaning oil;
A water scrubber for scrubbing the tar-containing combustible gas discharged from the oil scrubber with scrubbing water ;
A solid-liquid separator for separating tar and dust from the cleaning oil discharged from the oil scrubber;
A combustible gas production apparatus, comprising: a cleaning oil circulation line for circulating cleaning oil from which tar and dust have been separated by the solid-liquid separator to the oil scrubber .

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