JP2018095746A - Gasification apparatus and method of producing product gas - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the gasification efficiency of an organic raw material, enable the use of coarsely pulverized organic raw material, and downsize the gasifier.
SOLUTION: A reaction tube 104, a raw material introduction port 105a for introducing an organic raw material M1 into the reaction tube 104, a gasifying agent introduction port 106a for introducing a gasifying agent M2 into the reaction tube 104, and a raw material introduction port 105a. And a gasifier including a plurality of shelf plates 120 and 130 disposed between the gasifying agent introduction port 106a.
[Selection] Figure 1

Description

  The present invention relates to a gasifier for gasifying an organic material and a method for producing a product gas (gas fuel) from the organic material.

  At present, the spread of renewable energy is an urgent issue from the viewpoint of future energy and global warming prevention. In Japan, compared to solar power generation and wind power generation, especially wood-based and herbaceous solid biomass Energy use is not progressing. The reason for this is that due to the domestic land and forest conditions, intensive use of large-scale biomass plants has not been established, and there is no choice but to produce locally-produced, local-consumption or small / medium-scale distributed energy scales. One of the reasons for this is that no technology has been developed that is economically and economically feasible.

  In order to use the energy of biomass with high efficiency, it is effective not to use direct combustion but to use it once in a gas fuel state, and development of biomass gasification technology has been continued in a wide range of fields. Most of them are partial oxidation methods in which biomass is partially burned at a theoretical combustion equivalent ratio or less using air or water vapor / oxygen as a gasifying agent. However, this partial oxidation method has low gasification efficiency, generates a lot of soot and tar, and the exhaust gas used for the heat of gasification reaction is mixed into the product gas, so high quality and high calorie gas fuel cannot be obtained. .

  In recent years, a floating calorific gasification method has been developed that can produce high-calorie clean gas fuel suitable for power generation gas engines from solid biomass, and has demonstrated that it can be used for gas engine fuels, chemical synthesis gas feedstocks, etc. The contents are shown in the following Patent Document 1 and Patent Document 2, but at present, while maintaining high quality and high calorie gas fuel utilizing this gasification technology, Improvement requirements necessary for profitability are required. The requirements are reduction of energy for raw material pretreatment, improvement of performance by improving gasification efficiency, and compact and low cost of equipment.

  The gasification method of Patent Document 1 is a method called floating external heat type, in which a metal reaction tube is used as a gasification space, biomass powder as an organic raw material and water vapor as a gasification agent are supplied to the space, The outside is heated to a high temperature of 800 ° C. or higher with high-temperature combustion gas (hereinafter abbreviated as “hot gas”), and the reaction heat necessary for the gasification reaction is given by radiation from the reaction tube heated to a high temperature. Because the combustion exhaust gas of the hot gas used for heating is not mixed into the product gas, high quality and high calorie product gas can be obtained, fossil alternative gas fuel, gas engine fuel, gas turbine fuel, etc. It has come to be used as a gas fuel for various purposes.

However, Patent Document 1 has the following drawbacks.
The first drawback is that the biomass powder needs to be suspended by water vapor, so that the powder diameter is required to be about 3 mm under and the pulverization power is increased.
The second disadvantage is that when the water vapor that is a gasifying agent is reduced, the powder floating state cannot be maintained, and the coarse powder becomes unreacted carbide and falls or becomes a source of tar and soot. This means that clean gas fuel cannot be obtained.

  Patent Document 2 is an external heat radiation gasification method similar to Patent Document 1, but is a method in which the coarse powder falling without floating is gasified on the perforated plate below the reaction chamber. As a result, the finely pulverized power condition is relaxed, and raw materials pulverized to some extent can be used.

However, when viewed as a practical gasifier, Patent Document 2 leaves the following drawbacks.
The first drawback is that when there are many coarse powders of 3 mm or more, the amount of coarse powder deposited on the perforated plate increases, the gasification reaction time becomes remarkably long, and the gasification ability decreases.
The second drawback is that when the amount of water vapor supplied as a gasifying agent is lowered, the amount of coarse powder deposited on the perforated plate increases more and more, and the gasification reaction time becomes longer, resulting in gasification performance. Therefore, it is difficult to reduce the reaction water, and it is necessary to supply an excessive amount of water vapor, so that the thermal efficiency of gasification is lowered.

Japanese Patent No. 4227771 Japanese Patent No. 4986080

  In response to the above-mentioned circumstances, the present inventors are developing gasification technology, which is a basic technology for utilizing high energy of biomass. While following the above, further technical improvements are being made. The basic principle of gasification in Patent Documents 1 and 2 is that external heat radiation type steam that gives gasification reaction heat to a gasification body (mixed fluid of biomass and steam) by radiant heat from the reaction tube wall by heating from the outside of the reaction tube It is a reforming reaction. As a result, a practical technique for thermochemically generating high-quality, high-calorie gas fuel has been established. The generated gas can be used as a gas fuel for a gas engine and a gas turbine as it is, and although it is a small plant, high power generation efficiency exceeding the efficiency of large-scale combustion power generation using a steam turbine is obtained. The resulting product gas is mainly composed of hydrogen and carbon monoxide and can also be used as a synthesis gas for chemical synthesis of liquid fuels such as methanol, ethanol and GTL (liquid fuel synthesis from gas). is there. In this way, the technology has many advantages. However, when the profitability and economy as a practical machine are viewed, further functional improvements are required.

  In view of the above, an object of the invention disclosed in the present application is to provide a gasification apparatus and a production gas production method that can gasify an organic raw material suitably. In one aspect, a gasifier that can be substituted for Patent Documents 1 and 2, and / or a gasifier that is superior to Patent Documents 1 and 2, and / or a gasifier that improves or eliminates the disadvantages of Patent Documents 1 and 2. It is an object to provide an apparatus. A further aspect is to improve the gasification efficiency of the organic raw material, enable the use of coarsely pulverized organic raw material, and / or downsize the gasifier.

The present invention discloses the following invention.
<Configuration 1>
A reaction tube;
A raw material inlet for introducing an organic raw material into the reaction tube;
A gasifying agent introduction port located below the raw material introduction port for introducing a gasifying agent into the reaction tube;
A gasifier having a plurality of stages of shelves arranged between the raw material inlet and the gasifying agent inlet.
<Configuration 2>
The gasifier according to Configuration 1, wherein the shelf board has a mesh.
<Configuration 3>
The gasifier of the structure 1 or 2 in which the said shelf board has an opening which can drop an organic raw material.
<Configuration 4>
The gasification device of configuration 3, wherein the position of the opening is different for each of the shelves at each stage.
<Configuration 5>
The gas according to any one of configurations 1 to 4, wherein a distance between the raw material inlet and the uppermost shelf and a distance between the gasifying agent inlet and the lowermost shelf are larger than a diameter of the reaction tube. Device.
<Configuration 6>
A structure having control means for controlling the introduction of the gasifying agent and the organic raw material into the reaction tube so that the weight ratio R of the supply amount of the gasifying agent / organic raw material becomes 0.2 ≦ R ≦ 1.0. The gasifier in any one of 1-5.
<Configuration 7>
A reaction tube;
A raw material inlet for introducing an organic raw material into the reaction tube;
A gasifying agent introduction port located below the raw material introduction port for introducing a gasifying agent into the reaction tube;
A method for producing a product gas using a gasifier having a plurality of shelves arranged between the raw material inlet and the gasifying agent inlet,
With the reaction tube heated,
An organic raw material is introduced into the reaction tube from the raw material introduction port, and a gasifying agent is introduced into the reaction tube from the gasification agent introduction port.

  The organic raw material of the present application is preferably biomass, particularly powdery biomass. The gasifying agent is preferably water vapor.

1 shows a gasifier 1 according to an embodiment of the present invention. An exemplary shelf 120 is shown. An exemplary shelf board 130 is shown. The system diagram of the whole plant of the gasifier 1 is shown. The gasification apparatus 1A of other embodiment is shown. Furthermore, the gasification apparatus 1B of other embodiment is shown. The condition and result of the test which evaluated the effect of embodiment of this invention are shown.

  FIG. 1 shows a gasifier 1 according to an embodiment of the present invention. A reaction furnace main body 101 surrounded by a heat insulating wall 102 incorporates a reaction tube 104, and the reaction tube 104 is heated from the outer surface by a hot gas HG.

  The reaction tube 104 is a vertical cylindrical tube having an inner diameter D. Other cross-sectional shapes (for example, an ellipse, a quadrangle, a hexagon, an octagon, etc.) may be used. The internal space of the reaction tube 104 is called a gasification space.

  A raw material introduction tube 105 and a gasifying agent introduction tube 106 are connected to the reaction tube 104. The tip of the raw material introduction pipe 105 is a raw material introduction port 105a, and the tip of the gasification agent introduction pipe 106 is a gasification agent introduction port 106a. The gasifying agent introduction port 106a is located below the raw material introduction port 105a.

  A multistage shelf 110 is disposed at a height position between the raw material inlet 105a and the gasifying agent inlet 106a. The multi-level shelf 110 of this example is composed of two levels of shelf plates 120 and 130. 2 and 3 show exemplary shelf boards 120 and 130 in plan view.

  The shelf 120 is circular and is attached to the inner wall of the reaction tube 104 by an attachment member 121. The shelf board 130 has a donut shape, and the outer peripheral portion is directly attached to the inner wall of the reaction tube 104.

  The shelf 120 has an opening 122 between the reaction tube 104 and the shelf 130 has an opening 132 in the center. The sizes of the openings 122 and 132 are preferably such that the pulverized organic raw material M1 can easily pass therethrough. The area of the shelf plates 120 and 130 is preferably 50 to 90% of the cross-sectional area of the reaction tube 104, and more preferably 60 to 80%. It is preferable to change the positions of the openings 122 and 132 in each step so that the openings 122 and 132 do not overlap vertically. In order to adjust the deposition amount and the falling speed of the organic raw material M1, the shelf plates 120 and 130 may be provided with an inclination. For example, the inclination may be lowered toward the openings 122 and 132.

  The shelf plates 120 and 130 are preferably made of mesh. In particular, wire mesh and porous ceramics are preferable. The mesh should have a size that the organic raw material M1 cannot pass through. The mesh is preferably smaller than the pulverized size of the organic raw material M1. The mesh is selected to be 0.5 to 10 mm depending on the raw material size and the raw material properties (ease of dropping).

  The distance L1 between the shelf 120 and the raw material inlet 105a and the distance L2 between the shelf 130 and the gasifying agent inlet 106a are preferably equal to or greater than the inner diameter D. The distance L3 between the shelf plate 120 and the shelf plate 130 is preferably 1/2 or more of the inner diameter D, and particularly preferably greater than or equal to the inner diameter D.

  The organic raw material M1 and the gasifying agent M2 are introduced into the reaction tube 104 from the raw material introducing port 105a and the gasifying agent introducing port 106a, respectively, and are gasified by receiving radiant heat from the tube wall to generate a product gas FG. The organic raw material M1 falls stepwise while staying on the shelf plates 120 and 130 on the way. Therefore, even if the supply amount of the gasifying agent M2 is small, an efficient gasification reaction occurs. By setting L1 to L3 to the above dimensions, the radiant heat necessary for the reaction can be efficiently supplied. The product gas FG generated by the gasification reaction is sent from the extraction pipe 108 above the reaction pipe 104 to the utilization system outside the furnace. Reaction residues such as ash M3 can be discharged from the discharge port 107 below the reaction tube 104.

  The organic raw material M1 of this embodiment is biomass. Pulverized biomass is preferred. The organic raw material M1 may include other components such as moisture and soil. The gasifying agent M2 is reaction water (or water vapor). The gasifying agent M2 of this embodiment may include other components such as oxygen, carbon dioxide, nitrogen, and air.

From the effective radiation transmission length from the reaction tube 104, the inner diameter D is preferably 35 cm or less. The supply amount of the organic raw material M1 is based on 200 kg / h · m ² or less with respect to the cross-sectional area of the reaction tube. In order to allow the steam reforming reaction to proceed sufficiently, the reaction tube 104 is preferably heated to 800 ° C. or higher. The ratio R (= W / B) of the supply amount W (g / min) of the gasifying agent M2 to the supply amount B (g / min) of the organic raw material M1 is preferably 0.2 ≦ R ≦ 1.0. In the above embodiment, the two-stage shelf plates 120 and 130 are shown, but three or more stages may be used.

  FIG. 4 is a system diagram of the entire plant of the gasifier 1. Part of the organic raw material powder as a raw material is sent from the raw material tank 201 to the hot gas generation furnace 206 as fuel, and hot gas HG of 800 ° C. or higher is sent to the reaction furnace by normal combustion with air. On the other hand, a part of the raw material from the raw material tank 201 is supplied as an organic raw material M1 to the gasification space of the reaction tube 104 through the raw material hopper 209, the feeder 210, and the raw material introduction pipe 105. The water vapor as the gasifying agent M2 is adjusted to a predetermined temperature by the steam superheater 208 using the hot gas HG used for heating the reaction furnace body 101 as a heat source by adjusting the flow rate of the reaction water M4 with the flow rate control valve 207. And is supplied to the gasification space from the gasifying agent introduction pipe 106 below the reaction pipe 104. In the gasification space in the reaction tube 104, the organic raw material M1 from the feeder 210 is received by the multistage shelf 110 and gasified while dropping from the upper shelf 120 to the lower shelf 130 while being stepped. Upon receipt of the radiant heat from the agent M2 and the reaction tube wall, a steam reforming gasification reaction is generated and gasified to generate a product gas FG. Ash M3 generated by the reaction is discharged from the bottom of the reaction tube 104. The generated gas FG is sucked by the roots blower 220, is sent to the engine 214 through the gas purifier 212 and the gas tank 213, and is generated and transmitted 217 by the generator 216. When the product gas FG is used as a synthesis gas for a chemical plant raw material, it is sent to the chemical plant 219 by the switching valve 218 before the engine 214 and used.

  FIG. 5 shows a cluster-type gasifier 1A in which a plurality of reaction tubes 104 are housed in one reaction furnace body 101 in order to increase the capacity. The structure / function of each reaction tube 104 can be the same as that of the reaction tube 104 of the gasifier 1. However, the exhaust of the hot gas HG and the product gas FG from each reaction tube 104 are collected in the hot gas manifold 140 and the product gas manifold 141, respectively, and sent out of the reaction furnace.

  Experiments were carried out to confirm whether the gasification reaction occurred without any problem and the target product gas properties were obtained even when the raw material of coarse pulverization was used and the supply amount of the gasifying agent was minimized. . A system diagram of a small tester 1B of the gasifier used in the experiment is shown in FIG. A cylindrical reaction tube 104 made of SUS was vertically arranged in the electric furnace 301. The outer wall of the reaction tube 104 is uniformly heated by the electric furnace 301. The gasification space in the reaction tube 104 has an inner diameter of 54 mm and a length of 900 mm, and a multistage shelf 110 comprising two stages of shelf plates 120 and 130 is provided at a height between the raw material introduction port 105a and the gasifying agent introduction port 106a. Provided. The shelf 120 is circular and is disposed in the center of the gasification space, and the shelf 130 is donut-shaped and disposed on the outer periphery of the gasification space. The shelf plates 120 and 130 are both 1 mm nets. The distance between the shelf 120 and the raw material inlet 105a was 500 mm, and the distance between the shelf 130 and the gasifying agent inlet 106a was 400 mm.

  The organic raw material (biomass) M1 in the raw material tank 201 is dropped and supplied from the raw material introduction port 105a by the feeder 210. At the same time, the reaction water M4 is evaporated by the electric heating steam generator 302 and further heated through the steam superheater 303. The agent (steam) M2 was supplied to the reaction tube 104 in an upward flow from the gasifier inlet 106a. The generated product gas FG was cooled by a water cooling tube 304 and collected in a gas tank 213 after removing dust by a filter 305. The product gas FG thus obtained was sampled and the gas composition was analyzed using a gas chromatograph. The amount of generated dust was disassembled and weighed after the test.

  The test conditions and results are summarized in FIG. Here, the entire system pressure is a normal pressure. Test numbers (1-1) to (1-3) in FIG. 7 show the test conditions and test results of the present invention. Test numbers (2-1) to (2-3) are typical test conditions and test results of Patent Document 1.

  Test numbers (1-1) to (1-3) are 2.2 times the biomass supply amount B per reaction tube cross section and the reaction water supply amount W to test numbers (2-1) to (2-3). Was 1/2. Therefore, the ratio R (= W / B) of the biomass supply amount B to the reaction water supply amount W is 0.9 for the former and 4 for the latter. In (1-1) to (1-3), the coarse organic powder M1 having a particle size of 0.3 to 8 mm was used, but in (2-1) to (2-3), floating In order to obtain a state, an organic raw material M1 having a particle size of 0.3 mm or less was used.

Test No. (1-1) to (1-3) The composition of the product gas large _{H 2, C 2 H 4,} C 2 H 6 is small, clean from (2-1) to (2-3) This indicates a gasification reaction. This is proved from the fact that the dust amount D / BT is drastically reduced to 1/10 to 1/20. D / BT indicates the ratio of the unreacted portion of the feedstock. When converted to gasification rate, the method of the present invention exceeds 99%, whereas the conventional floating external heat method has 94%. Stopped below. Here, the gasification rate indicates the gasification rate of only the raw material raw powder different from the gasification efficiency including the external heat.

  When this test result is comprehensively evaluated, the multistage shelf 110 is provided at the intermediate position of the reaction tube 104, so that the amount of reaction water relative to the amount of raw material supply can be reduced, the gasification rate and the gasification efficiency are improved, It became clear that a safe gas fuel could be obtained. Moreover, since it is possible to use a coarsely pulverized organic raw material of about 8 mm, reduction of pulverization power can be achieved.

Hereinafter, the significance of the present invention will be considered from the theoretical viewpoint. Based on the background described in the problem to be solved by the invention, it can be said that it is desirable to achieve the following four problems.
1) Maintaining the basic conditions of the excellent gasification function of the external heat radiation gasification system to ensure “high quality and high calorie product gas” 2) Making the coarsely pulverized raw material usable 3) “Excessive” To improve thermal efficiency and gasification efficiency by reducing the amount of reaction water
4) By improving the performance of 2) and 3) above, the gasification efficiency per gasification space is improved to make a “compact gasifier”.

Problem 1) is that the most important requirement of the radiant external heating system to obtain “high quality and high calorie product gas” is the required temperature from the reaction tube wall for the biomass raw material to produce steam and the heat of reaction required for the gasification reaction It is to cover with the above radiant heat.
First, the temperature required for reaction heat is at least 800 ° C for the char component (fixed carbon) in the biomass composition to be gasified by the steam reforming reaction. It is desirable to heat it.
Although the biomass gasification reaction heat varies depending on the reaction temperature, from the previous basic experiments and analysis, the reaction heat increases as the temperature increases, and the H ₂ composition ratio in the product gas increases. When the reaction temperature increases from 800 to 1000 ° C., the heat of reaction increases from approximately 500 to 1100 kcal / kg. The necessary reaction tube area for giving this reaction heat by reaction tube wall radiant heat is expressed by the following equation.
A = H × W / Φ · σ [Tw ⁴ −Tg ⁴ ] (1)
However,
A = Radiation area surrounding the gasification body (reaction tube area)
H = heat of reaction (kcal / kg)
W = biomass raw material (kg / h)
Φ = Radiation form factor of gasification body and reaction tube (-)
σ = Stephan Boltzmann constant [4.88 × 10 ⁻⁸ ] (kcal / m ² hK ⁴ )
Tw = Reaction tube wall temperature (K)
Tg = Gas body temperature (K)
That is, satisfying this condition is an indispensable condition for producing a “high quality / high calorie product gas”.
Tw = 900 ° C. + 273 ° C. = 1173K
Tg = 800 ° C. + 273 ° C. = 1073K
H = 750 kcal / kg
W = 29kg / h
Φ = 0.7
Assuming that the required radiation area for gasification under this condition is obtained from the equation (1), A = 0.773 m ² . Therefore, in the case of a reaction tube having an inner diameter D of 0.3 m, a tube length of 0.82 m or more is required.

  Problem 2) In Patent Document 1, it is necessary to keep the raw material powder in a floating state with water vapor. Therefore, it is necessary to make the pulverization degree (pulverization size) of the raw material very small, such as 0.5 mm or less. In the present invention, the organic raw material stacked on the shelf plate is gasified while dropping the organic raw material step by step using a multistage shelf, so that an organic raw material having a large pulverized size can be efficiently gasified. .

Regarding the relationship between pulverization and power consumption, the data shown in Table 1 is obtained in a hammer mill pulverization test of cedar. As is apparent from this data, the power consumed for grinding can be reduced by increasing the grinding size. For example, by changing from pulverization of 3 mm or less to pulverization of 6 mm or less, 3.8% of the total energy consumption can be saved, which is in agreement with an improvement of 3.8% in thermal efficiency and gasification efficiency. Furthermore, there is also an effect that it can be advantageously developed for expansion of biomass species that can be used as raw materials. Thus, it is significant that an organic raw material having a large pulverized size can be used.

Next, the thermal efficiency and gasification efficiency by “reducing excessive reaction water” in Problem 3) will be examined.
Gasification efficiency is defined by the following cold gas efficiency.
Gasification efficiency (%) = Cold gas efficiency (%) = Q1 ÷ (Q2 + Q3) x 100 (%) (2)
However,
Q1: Low calorific value of the product gas at normal temperature Q2: Low calorific value of organic raw material Q3: Low calorific value of fuel used for generating hot gas Here, Q1 is a fixed amount determined by reaction temperature and reaction time, Q2 is a fixed amount determined by the amount of organic raw material supplied, and Q3 is a “gasification reaction heat amount” and a “heating amount to the reaction temperature of the gasifying agent (steam)”. The “gasification reaction heat amount” is a fixed amount determined by the reaction temperature and the reaction time. Therefore, to improve the gasification efficiency, it is effective to reduce the “heating amount to the reaction temperature of the gasifying agent (steam)”. Therefore, the supply amount of the gasifying agent (steam) is set to W (kg), the organic raw material Assuming that the supply amount is B (kg), the ratio R = W / B may be reduced.

Therefore, first, the minimum required amount of reaction water with respect to the organic raw material supply amount is obtained.
An example of the results of the external heat radiation gasification reaction of the present invention is shown as a semi-empirical formula as follows.
● When the reaction temperature is 800 ℃ (hydrogen H ₂ volume composition: 34.7%)
C _1.4 H ₂ O _0.9 + 0.36H ₂ O → 0.70H ₂ + 0.72CO + 0.27CH ₄ + 0.08C ₂ H ₂ + 0.25CO ₂
● When the reaction temperature is 900 ℃ (hydrogen H ₂ volume composition: 46.0%)
C _1.4 H ₂ O _0.9 + 0.70H ₂ O → 1.20H ₂ + 0.61CO + 0.20CH ₄ +0.05 C ₂ H ₂ + 0.49CO ₂
● If a reaction temperature 1000 ° C. (hydrogen H ₂ volume composition: 52.0%)
C _1.4 H ₂ O _0.9 + 1.01H ₂ O → 1.65H ₂ + 0.53CO + 0.16CH ₄ + 0.01C ₂ H ₂ + 0.68CO ₂
However, C _1.4 H ₂ O _0.9 is a simplified molecular formula obtained from elemental analysis of cedar wood, and the molecular weight is 33.2.

From the above reaction formula, the required minimum amount of water vapor (reaction water H ₂ O) for gasifying 1 mol of organic raw material (33.2 g) is 6.48 g (1 mol of water, 18 g × 0.36) at 800 ° C., It is 12.6g at 900 ° C and 18g at 1000 ° C. Therefore, the necessary minimum value of the R value is 0.195 at 800 ° C., 0.379 at 900 ° C., and 0.542 at 1000 ° C. In an actual gasification reaction, if the amount of water vapor can be brought close to the above required minimum amount, the highest improvement in gasification efficiency can be achieved.

However, in Patent Documents 1 and 2, since it is necessary to advance the gasification reaction in a state where the organic raw material is suspended, it is necessary to supply an excessive amount of water vapor in a ratio R = 2 to 2.5. The normal operating conditions based on the experience of the present inventors are that the supply amount of organic raw material powder to the tube cross-sectional area is 300 kg / m ² h or less, and the maximum reaction tube diameter is 350 mm or less from the ability to transmit radiation from the tube wall. However, when the amount of water vapor is set to the required minimum amount under these operating conditions, the flow rate of the water vapor is reduced to about 0.1 m / s, and no buoyancy to float the organic raw material is obtained. Almost all will fall.

  On the other hand, in the present invention, the organic raw material is dropped stepwise using a plurality of shelf boards, and the organic raw material stacked on the shelf boards is gasified. Is unnecessary, and the gasification reaction can sufficiently proceed with water vapor closer to the necessary minimum.

When the supply amount of water vapor is minimized (case 1) and when the raw material supply ratio R is 2 (case 2), the reaction is compared with the amount of heat (corresponding to external heat) as follows.
● Case 1
1) Heat required for gasification of 1 kg of organic raw material at a reaction temperature of 800 ° C:
Reaction heat 441kcl / kg + Steam overheated 999 × 0.195kcal / kg = 636kcal / kg
2) Heat required for gasification of 1 kg of organic raw material at a reaction temperature of 900 ° C:
Reaction heat 583kcl / kg + Steam superheat 1050 × 0.379kcal / kg = 981kcal / kg
3) Heat required for gasification of 1 kg of organic raw material at a reaction temperature of 1000 ° C:
Reaction heat 707kcl / kg + Steam superheat 1104 × 0.542kcal / kg = 1305kcal / kg
● Case 2
1) Heat required for gasification of 1 kg of organic raw material at a reaction temperature of 800 ° C:
Heat of reaction 441 kcl / kg + Steam overheated 999 × 2 kcal / kg = 2439 kcal / kg
2) Heat required for gasification of 1 kg of organic raw material at a reaction temperature of 900 ° C:
Reaction heat 583kcl / kg + Steam superheat 1050 × 2 kcal / kg = 2683kcal / kg
3) Heat required for gasification of 1 kg of organic raw material at a reaction temperature of 1000 ° C:
Reaction heat 707kcl / kg + Steam superheat 1104 × 2 kcal / kg = 2915kcal / kg

The above is summarized in Table 2. When the supply amount of water vapor is minimized (Case 1), the amount of heat required for the reaction is 1/2 or less that of Patent Document 1 (Case 2), and "reducing excess reaction water" The magnitude of the effect is clear.

Since the performance of the gasifier is evaluated by gasification efficiency, the gasification efficiency of case 1 and case 2 was compared using the examination results in Table 2. Here, the heat loss to the outside of the hot gas used for heating the reaction tube was 25%, and the organic raw material and the hot gas fuel were based on the lower heating value of 4400 kcal / kg anhydrous ashless.
The evaluation results are shown in Table 3. Table 3 shows a large gasification efficiency improvement of about 1.3 times. This is because the gasification efficiency of the normal partial oxidation gasification method is 60 to 65% and 63 to 70% in Patent Document 1, whereas the supply amount of water vapor is minimized to 83 to 90%. % Gasification efficiency can be achieved. This is the highest gasification efficiency ever. The improvement in gasification efficiency is about 30%.

  Problem 4) A “compact gasifier” can be realized if the effect of the multistage shelf can be expected. Although the size of the steam generator can be reduced by reducing the reaction water in Problem 2, and the size of the biomass feedstock can be reduced by increasing the gasification efficiency in Problem 3, the reaction tube length can be shortened the most by multistage gasification using multistage shelves. Produce an effect. In the radiant external heat type, the gasification capacity is determined by the amount of radiant heat from the reaction tube wall, but the organic raw material on the shelf does not float and is gasified in a stacked quasi-static state. It will be received from the reaction tube wall of the specified range. Therefore, sufficient gasification capability can be obtained by setting the reaction tube lengths L1, L2, and L3 above and below the shelf so as to ensure the necessary radiation area. In the gasifier using the two-stage multistage shelf 110, assuming that the inner diameter D of the reaction tube 104 is 0.3 m, L1 = 0.3 m, L2 = 0.3 m, L3 = 0.15 m A sufficient gasification capability can be obtained with the reaction tube 104 of about 0.8 m. In the reaction tubes of Patent Documents 1 and 2, compared with the fact that the total length of 10 m or more was necessary mainly due to the floating unreacted raw material (mainly fixed carbon) flowing to the wake part after the primary gasification. The remarkableness of compactification is clear.

  If the number of shelves is further increased under the same design philosophy as above, that is, “a certain reaction tube length is ensured above and below the shelf”, the gasification capacity per reaction tube Increases accordingly, and the entire reactor can be compactly collected.

The product gas produced by the present apparatus has a high composition ratio of H ₂ and CO and can be used not only as a gas fuel for engines, turbines, etc., but also as a synthesis gas as a raw material for chemical synthesis. In this case, the H ₂ / CO volume ratio is desirably 2/1. In this case, the H ₂ / CO volume ratio can be increased by increasing the reaction temperature, or decreasing the load of the gasification reactor (feeding amount of raw materials and water vapor) and increasing the reaction time.

  Coarse powder such as 8 mm is provided by providing a plurality of groups of shelves for receiving the organic raw material at the middle position of the reaction tube, and by setting the gasification agent / organic raw material supply amount ratio R to 1 or less and low reaction water conditions. The organic raw material powder containing the body can be gasified by an external heat radiation steam reforming reaction. High-performance gas can be expected to have a gasification efficiency of 80-90% by greatly reducing the pulverization power of biomass because the coarse powder of 8mm size can be used as the organic raw material powder. Can be realized. In addition, the product gas retains the high quality and high calorie properties that are the features of the external heat radiation method, and can be used not only as a gas fuel but also as a synthesis gas as a liquid fuel chemical synthesis raw material.

  The dimensions, shape, arrangement, number, material, procedure, and the like of the device and its elements described in the above embodiments are examples, and other modes are possible.

1, 1A, 1B ... gasification apparatus 101 ... reaction furnace body 102 ... heat insulation wall 104 ... reaction tube 105 ... raw material introduction tube 105a ... raw material introduction port 106 ... gasification Agent introduction pipe 106a ... Gasification agent introduction port 107 ... Discharge port 108 ... Extraction pipe 110 ... Multistage shelves 120, 130 ... Shelf plates 122, 132 ... Openings 140 ... Heat Gas manifold 141 ... Production gas manifold 201 ... Raw material tank 203 ... Auxiliary fuel 204 ... Blower 205 ... Air 206 ... Heat gas generator 207 ... Flow control valve 208 ··· Steam superheater 209 ··· Raw material hopper 210 ··· Feeder 212 · · · Gas purification device 213 · · · Gas tank 214 · · · Engine 215 · · · Engine exhaust 216 · · · Generator 217 · · · Power generation Power transmission 218 ... Switching valve 219 ... Chemical plant 220 ... Roots blower 221 ... Chimney 301 ... Electric furnace 302 ... Electric heating steam generator 303 ... Steam superheater 304 ... Water cooling Pipe 305 ... Filter M1 ... Organic raw material M2 ... Gasifying agent M3 ... Ash M4 ... Reaction water FG ... Generated gas HG ... Hot gas

Claims (7)

A reaction tube;
A raw material inlet for introducing an organic raw material into the reaction tube;
A gasifying agent introduction port located below the raw material introduction port for introducing a gasifying agent into the reaction tube;
A gasifier having a plurality of stages of shelves arranged between the raw material inlet and the gasifying agent inlet.   The gasifier according to claim 1, wherein the shelf board has a mesh.   The gasifier according to claim 1 or 2, wherein the shelf board has an opening through which an organic raw material can drop.   4. The gasifier according to claim 3, wherein the position of the opening is different for each shelf plate of each stage.   The distance between the raw material inlet and the uppermost shelf, and the distance between the gasifying agent inlet and the lowermost shelf are larger than the radius of the reaction tube. Gasifier.   A control means for controlling the introduction of the gasifying agent and the organic raw material into the reaction tube so that the weight ratio R of the supply amount of the gasifying agent / organic raw material becomes 0.2 ≦ R ≦ 1.0. The gasifier in any one of claim | item 1 -5. A reaction tube;
A raw material inlet for introducing an organic raw material into the reaction tube;
A gasifying agent introduction port located below the raw material introduction port for introducing a gasifying agent into the reaction tube;
A method for producing a product gas using a gasifier having a plurality of shelves arranged between the raw material inlet and the gasifying agent inlet,
With the reaction tube heated,
An organic raw material is introduced into the reaction tube from the raw material introduction port, and a gasifying agent is introduced into the reaction tube from the gasification agent introduction port.

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