JP4295793B2 - Biomass gasifier - Google Patents

Description

  The present invention relates to a biomass gasification furnace and a biomass gasification method capable of efficiently using biomass and performing clean and highly efficient gasification.

  In general, biomass refers to organisms (such as agricultural products or by-products, wood, plants, etc.) that can be used as energy sources or industrial raw materials, and are produced by the action of solar energy, air, water, soil, etc. Is infinitely reproducible.

By using the biomass, fuel and methanol can be produced. Further, since biomass as waste can be treated, it is useful for environmental purification, and newly produced biomass is also grown by CO ₂ fixation by photosynthesis, so that it does not increase atmospheric CO ₂ .

  For example, fermentation methods and hydrothermal decomposition methods have been proposed as conventional methods for converting biomass to alcohol. However, the former fermentation method uses only sugar and starch as raw materials and takes a long time for fermentation. In addition, it is necessary to install a large-capacity fermentation tank, and the latter hydrothermal decomposition method has problems of high temperature, high pressure, and low yield. In addition, there is a problem that a large amount of biomass residues are supplied together and the utilization rate of biomass is low.

On the other hand, in the case of biomass gasification, for example, a gasification furnace such as a fixed bed or a fluidized bed was used, but only the surface of the biomass particles reacted and did not react uniformly to the inside, There is a problem that tar is generated and the generated gasification gas is not a raw material for efficient methanol synthesis because it has a small amount of H ₂ and CO.

  Further, there is a problem in that the generated tar adheres to the inside of the furnace and also adheres to equipment or the like installed on the downstream side, resulting in trouble in operation.

  Therefore, in the past, it was decided to burn at a high temperature by supplying a large amount of oxygen, but in this case, a high temperature region partially exceeding 1200 ° C. was formed, and a large amount of soot was generated by the combustion of biomass. There is a problem of end.

  In view of the above problems, an object of the present invention is to provide a biomass gasification furnace capable of performing clean and highly efficient gasification and achieving complete gasification of biomass.

  A first invention that solves the above-described problem is a biomass gasification furnace that uses biomass as a raw material and obtains a product gas by gasification with steam, and is connected to the gasification furnace body and the gasification furnace body, Supply means for supplying biomass into the gasification furnace main body, a heating means provided to surround the gasification furnace main body, heating the gasification furnace main body, and connected to the heating means, A biomass supply means for supplying biomass into the heating means, an oxidant supply means connected to the heating means for supplying an oxidant into the heating means, and between the heating means and the gasifier main body And a water vapor supply means connected to the plurality of through holes of the partition wall provided in the gas supply section for supplying water vapor into the gasification furnace.

  A second invention is characterized in that, in the first invention, the partition wall is a side wall of the gasifier main body.

  According to a third aspect of the present invention, the gas purification apparatus includes a gas purification apparatus that purifies gas gasified in the first or second biomass gasification furnace, and a gas turbine that uses the purified gas as fuel.

The fourth invention includes a gas purification device for gas purification of gas gasified in the first or second biomass gasification furnace, and a methanol synthesis device for synthesizing methanol from H ₂ and CO in the purified gas. It is characterized by that.

  A first invention is a biomass gasification furnace that uses biomass as a raw material and obtains a product gas by gasification with steam, and is connected to the gasification furnace main body and the gasification furnace main body. Supply means for supplying biomass to the gasification furnace body, heating means for heating the inside of the gasification furnace main body, connected to the heating means, and biomass into the heating means Biomass supply means for supplying gas, oxidant supply means connected to the heating means for supplying an oxidant into the heating means, and a partition provided between the heating means and the gasifier main body The steam supply means connected to the plurality of through holes and supplying steam into the gasification furnace is provided, so that it is possible to efficiently obtain a high amount of heat applied to the steam necessary for biomass gasification.

  According to a second invention, in the first invention, since the partition wall is a side wall of the gasifier main body, the constituent members can be simplified.

  Since the third invention comprises a gas purification device that purifies the gas gasified in the first or second biomass gasification furnace and a gas turbine that uses the purified gas as fuel, the biomass can be used effectively. A gas turbine can be driven.

The fourth invention includes a gas purification device for gas purification of gas gasified in the first or second biomass gasification furnace, and a methanol synthesis device for synthesizing methanol from H ₂ and CO in the purified gas. Therefore, efficient methanol synthesis becomes possible.

  Embodiments of the present invention will be described below, but the present invention is not limited to these embodiments.

[First Embodiment]
A first embodiment of the present invention will be described with reference to FIG.
FIG. 1 is a schematic view of a biomass gasification furnace according to the present embodiment.
As shown in FIG. 1, a biomass gasification furnace 10 according to the present embodiment obtains a product gas by thermal decomposition of biomass with water vapor at a high temperature, and is pulverized from a furnace top 11 to a predetermined particle size. A gasifier main body 16 made of a refractory material having a first biomass supply means 13A for supplying 12 to the interior of the furnace and a steam supply means 15 for supplying steam 14 to the interior of the furnace; A second biomass supply means 13B for supplying biomass 12 pulverized to a predetermined particle size into the furnace, and a fluidized bed combustion furnace 19 having an oxidant supply means 18 for supplying an oxidant 17 such as oxygen or air into the furnace. It is provided.

  Further, an ash reservoir 22 for the ash 21 in the biomass is formed at the lower portion of the furnace body 16.

  Moreover, the gas discharge part 23 is provided in the side wall lower part side of the furnace main body 16, and the produced gas 24 produced | generated by biomass gasification is sent out to the downstream.

  In the fluidized bed furnace 19, the biomass 12 supplied by the supply means 13 </ b> B is uniformly combusted while being convected, so that the combustion temperature in the furnace becomes uniform and the gasification furnace main body provided with the combustion heat inside Heat is uniformly applied to 16.

  In the gasification furnace main body 16, the biomass 12 for gasification is supplied from the top by the supply means 13 </ b> A, and the water vapor 14 from which oxygen is removed is similarly supplied by the supply means 15. As a result, the gasification biomass 12 is pyrolyzed and gasified with heat supplied by the radiant heat of combustion in the fluidized bed combustion furnace 19 while being mixed and fluidized with the water vapor 14 to generate a product gas 24.

The water vapor 14 from which the supplied oxygen is removed functions as a gasifying agent and is preferably superheated steam at 400 to 600 ° C. Thereby, pyrolysis gasification in a high-temperature steamed state is promoted, and adverse effects due to the generation of CO ₂ can be suppressed.

In general, the reaction mainly includes reactions of the following formulas (1), (2), and (3) using biomass (Cm H ₂ On) as a raw material and steam (H ₂ O) as a gasifying agent.

CO + H ₂ O → CO ₂ + H ₂ ... Formula (1)
C + H ₂ O → CO + H ₂ ... Formula (2)
C + 2H ₂ O → CO ₂ + 2H ₂ ... Formula (3)

In order to synthesize methanol using the product gas 24, the molar ratio of CO / H ₂ is preferably ½. For this reason, it is necessary to adjust so that reaction of said Formula (1), (2), (3) may be performed smoothly.

  One of the adjusting means is to control the temperature inside the gasification furnace main body 16 to 700 to 1000 ° C. The internal temperature of the gasifier main body 16 is controlled by the amount of biomass and oxidant supplied to the fluidized bed combustion furnace, and the amount and temperature of steam supplied to the gasifier.

The generated gas 24 is supplied together with some scattered particles from the exhaust section 23 through a heat exchanger and the like to a downstream device, for example, a methanol synthesis device (not shown).
On the other hand, surplus gas of the combustion exhaust gas 25 as a heat supply source for gasification is discharged to the outside.

  In the present embodiment, the first biomass supply means 13A and the water vapor supply means 15 are provided at the top of the furnace. However, the present invention is not limited to this, and is supplied from below or from the side. Also good. Moreover, the supply location may be not only one location but also a plurality of locations.

Here, in the present invention, the biomass 12 to be supplied is preferably supplied by pulverizing and drying the produced or discarded biomass.
Biomass in the present invention refers to biological resources that can be used as an energy source or industrial raw material (for example, agricultural products or by-products, wood, plants, etc.), and examples include sweet sorghum, napiergrass, spirulina, and the like. it can.

  In the present invention, the average particle diameter (D) of the pulverized biomass 12 is preferably 0.05 ≦ D ≦ 5 mm. This is because if the average particle size is 0.05 mm or less, the pulverization efficiency of biomass deteriorates, which is not preferable. On the other hand, when the average particle size exceeds 5 mm, the reaction is not promoted to the inside of the biomass, and high-efficiency gasification becomes difficult.

Moreover, in this invention, although the steam 14 supplied to the biomass gasification furnace 10 is supplied from a furnace top part, this invention is not limited to this, You may make it supply from the downward side or a side.
Moreover, the supply location is not limited to one location, and it may be supplied from a plurality of locations.

Moreover, it is preferable that the furnace pressure of the gasification furnace main body 16 shall be 1-30 atmospheres.
This is because when it is directly linked to the synthesis of methanol (or dimethyl ether), it is preferably near 80 atm, but it is necessary to use a gasification furnace having a pressure-resistant structure, which is not preferable because of high manufacturing costs. In addition, about 30 atmospheres, a superficial velocity becomes low and an apparatus can be made compact, and it is preferable.

Further, the superficial velocity in the furnace of the gasification furnace main body 16 is preferably set to gasification conditions of 0.1 to 5 m / s.
This is because, when the superficial velocity is 0.1 m / s or less, there is a concern about the phenomenon of biomass deposition in the reaction part, and as a result, the reaction pyrolysis decreases, whereas when it exceeds 5 m / s, the pyrolysis occurs. This is because satisfactory gasification cannot be achieved without complete removal.
In order to suitably convey the pulverized biomass, it is better to take the particle size of the biomass into consideration, and particularly preferably, when the average particle size of the biomass is 0.1 to 1 mm, the superficial velocity is set to 0.1. When the average particle diameter is 4 to 1 m / s and the average particle diameter is 1 to 5 mm, the superficial velocity is preferably 1 to 5 m / s.

  The obtained gas can be directly used as a fuel gas for a gas turbine after being purified by a gas purification means.

Moreover, it can also be used as a gas for producing methanol (or dimethyl ether) by adjusting the composition of H ₂ and CO gas in the gas.

[Second Embodiment]
Hereinafter, a system 100 that uses the obtained product gas 24 for methanol synthesis will be described with reference to FIG.

As shown in FIG. 2, a biomass methanol synthesis system 100 that synthesizes methanol using the product gas 24 produced by the biomass gasification furnace includes a gas 24 generated in the biomass gasification furnace 10 shown in FIG. A dust collector 101 that removes soot, a purifier 102 that purifies the gas after dust collection, a CO shift reaction device 104 that adjusts the composition of H ₂ and CO gas in the gas, and a booster that improves the gas pressure An apparatus 105, a methanol synthesizer 106 that produces (synthesizes) methanol (CH ₃ OH) from H ₂ and CO _{2 in} the gas, and a gas-liquid separator 109 that separates the exhaust gas 107 and methanol 108. To do.

The biomass 12 supplied into the gasification furnace 10 improves the gasification efficiency of the biomass in the gasification furnace 16 by heating the inside of the furnace uniformly outside by the fluidized bed furnace 19. The generated gas 24 is then dedusted by the dust collector 101 and then guided to the purifier 102 where it is cooled and water vapor is removed, and then the CO shift reactor 104 increases the amount of H _2. The pressure is increased to the pressure of methanol synthesis by the booster device 105 and guided to the methanol synthesis device 106, where the methanol 108 is manufactured. Thereafter, the methanol 108 and the exhaust gas 107 are separated.
Here, since CH4 remains in the exhaust gas 107, it may be reused as a heat source (fuel) that is supplied again to the gasification furnace main body 16 or preheats water vapor.

Incidentally, in order to improve the recovery rate of the methanol, the excess CO ₂ is CO ₂ removal unit (decarbonation apparatus) 110 for removing CO _2, such as amine wet CO ₂ removing device in the system final stage booster Extra CO ₂ may be removed by interposing between the apparatus 105 and the methanol synthesis apparatus 106.

As a result, the methanol raw material gas supplied to the methanol synthesizer 106 can remove excess CO _{2 and} have a molar ratio composition of CO and 2H _2. Methanol synthesis proceeds efficiently, and the supplied biomass is It can be efficiently synthesized into methanol.

[Third Embodiment]
A third embodiment of the present invention will be described with reference to FIG.
In addition, about the same member as the gasification furnace shown in FIG. 1, the same code | symbol is attached | subjected and the overlapping description is abbreviate | omitted.

  A biomass gasification furnace 30 according to the present embodiment is provided around a gasification furnace main body 31 provided with a biomass supply means 13A for supplying biomass 12 from the furnace top 11 and the gasification furnace main body 31, A combustion furnace 34 which is a heating means for supplying and burning the oxidant 17 to heat the inside of the gasification furnace main body 31, a plurality of through holes 32 are provided in the side wall 31a of the gasification furnace main body 31, and the A steam supply means for supplying the steam 14 between the side wall 31 a and the combustion furnace 34 is provided on the lower side of the gasification furnace main body 31.

    According to the present embodiment, the supplied steam 14 becomes high-temperature steam by the heat of the combustion furnace 34 and is supplied into the gasifier main body 31 to protect the gasifier main body 31 and The water vapor supplied to can be on the high temperature side (preferably 800 to 1000 ° C.).

  Thereby, in addition to the effects of the first embodiment, the side wall 31a can be protected, the durability can be improved, and the thickness of the side wall 31a can be reduced.

In this embodiment, the side wall 31a of the gasification furnace main body 31 functions as a partition wall formed between the gasification furnace body 31 and the combustion furnace 34. However, a separate partition wall portion is provided, and steam is supplied to the partition wall portion to supply steam. Heating may be performed.
Further, the combustion furnace 34 may use fluidized bed heating means as shown in the first embodiment so as to apply uniform heat to the steam 14.

[Fourth Embodiment]
A fourth embodiment of the present invention will be described with reference to FIG.
In addition, about the same member as the gasification furnace shown in FIG. 1, the same code | symbol is attached | subjected and the overlapping description is abbreviate | omitted.

The biomass gasification furnace 40 according to the present embodiment includes two supply means 13 for supplying biomass 12, steam supply means 15A for supplying steam 14, and oxidant supply means 18 for supplying oxidant 17. Gasification furnace main bodies 41A and 41B are provided, and ceramic balls 42 as heat storage materials are filled in the gasification furnace main bodies 41A and 41B.
Although the gasifier main body 41A and the gasifier main body 41B have the same configuration, a part of the supply means is omitted for convenience of explanation.

According to the present embodiment, the biomass 12 and the oxidant 17 are supplied into one gasifier main body 41A and the biomass is combusted by a combustion reaction to form the combustion furnace A, and the other gasifier main body ( In the combustion furnace, the heat storage material 42 is already stored by heating), and the steam 14 is supplied into the gas 41B and gasified by the steam 14 to form the gasification furnace B.
The ceramic balls 42 which are heat storage materials become high temperature (preferably 800 to 1000 ° C.) by biomass combustion, and become a heat medium for applying high temperature steam.
And by performing these alternately, the high calorie | heat amount given to the water vapor | steam required for biomass gasification can be obtained efficiently similarly to 1st Embodiment.

In the present embodiment, the ceramic balls 42 are used as the heat storage material, but the present invention is not limited to this as long as the medium stores high heat capacity.
In addition, you may make it stick a heat storage material on the inner surface of the side wall of a gasifier main body instead of a ceramic ball | bowl.
Alternatively, two or more gasification furnace main bodies may be provided, and these may be biomass-fired in order to heat the heat storage material, thereby sequentially contributing to the generation of high-temperature steam.

[Fifth Embodiment]
A fifth embodiment of the present invention will be described with reference to FIG.
In addition, about the same member as the gasification furnace shown in FIG. 1, the same code | symbol is attached | subjected and the overlapping description is abbreviate | omitted.

A biomass gasification furnace 50 according to the present embodiment includes a biomass supply means 13 that supplies biomass 12, a steam supply means 15 that supplies steam 14, and an oxidant supply means 18 that supplies oxidant 17. A gasification furnace main body 52 including a main body 51, a biomass supply means 13 for supplying biomass 12, a steam supply means 15 for supplying steam 14, and an oxidant supply means 18 for supplying oxidant 17, and a combustion furnace main body 51 And a rotary heat exchanger 53 interposed in the gasification furnace main body 52 so as to be rotatable about a vertical axis.
In the present embodiment, the rotary heat exchanger is provided in two places at the top and bottom, but the present invention is not limited to this and may be provided at one place or a plurality of places according to the heat exchange capacity.

  According to the present embodiment, the rotary heat exchanger 53 rotates in the combustion furnace main body 51 after accumulating heat generated by the combustion of the biomass 12, and heats the other gasification furnace main body 52, High-temperature steam necessary for biomass gasification (preferably 800 to 1000 ° C.) can be used.

  And by performing these alternately, the high calorie | heat amount given to the water vapor | steam required for biomass gasification can be obtained efficiently similarly to 1st Embodiment.

It is the schematic of the biomass gasification furnace concerning 1st Embodiment. It is the schematic of the methanol synthesis | combination system using the biomass gasification furnace concerning 2nd Embodiment. It is the schematic of the biomass gasification furnace concerning 3rd Embodiment. It is the schematic of the other biomass gasification furnace of 4th Embodiment. It is the schematic of the biomass gasification furnace concerning 5th Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Biomass gasification furnace 11 Top part 12 Biomass 13 Biomass supply means 14 Water vapor 15 Water vapor supply means 16 Gasification furnace main body (furnace main body)
DESCRIPTION OF SYMBOLS 17 Combustion oxidant 18 Combustion oxidant supply means 19 Fluidized bed furnace 21 Combustion residue 22 Ash storage part 24 Generated gas 30 Biomass gasification furnace 31 Gasification furnace main body 32 Through-hole 33 High temperature steam 34 Combustion furnace main body 40 Biomass gasification furnace 41 Furnace body 42 Ceramic ball 50 Biomass gasification furnace 51 Combustion furnace body 52 Gasification furnace body 53 Rotary heat exchanger 100 Biomass gasification system 101 Dust collector 102 Purifier 103 Scrubber 104 CO shift reactor 105 Booster device 106 Methanol synthesis Equipment 107 Exhaust gas 108 Methanol 109 Distillation equipment 110 Decarbonation equipment

Claims (4)

A biomass gasification furnace using biomass as a raw material and obtaining a product gas by gasification with steam,
A gasifier body,
Supply means connected to the gasifier main body and supplying biomass into the gasifier main body,
Heating means provided so as to surround the gasification furnace main body and heating the gasification furnace main body;
Coupled to the heating means, biomass supply means for supplying biomass into the heating means;
An oxidant supply means connected to the heating means for supplying an oxidant into the heating means;
It is connected to a plurality of through holes of a partition wall provided between the heating means and the gasification furnace main body, and comprises a water vapor supply means for supplying water vapor into the gasification furnace. Biomass gasifier. In claim 1,
A biomass gasifier characterized in that the partition wall is a side wall of a gasifier main body. A biomass gasification system comprising: a gas purification apparatus that purifies gas gasified in the biomass gasification furnace according to claim 1 or 2; and a gas turbine that uses the purified gas as fuel. A gas refining device for purifying gas gasified in the biomass gasification furnace according to claim 1 or 2, and a methanol synthesizer for synthesizing methanol from H ₂ and CO in the purified gas. Biomass methanol synthesis system.

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