JP2022067699A - Gasification system and operational method of gasification furnace - Google Patents

Abstract

To provide a gasification system and an operational method of a gasification furnace, that can suitably control a gasification reaction.SOLUTION: A gasification system comprises: a gasification furnace 1 that heats a gas raw material (wood chips) M as a carbon source together with a gasifying agent (air A, steam V) to generate a gasified gas G; combustion equipment (generator 2, tar combustion device 15) that burns fuel (gasified gas G, tar T) to generate an exhaust gas E; and an exhaust gas supply flow channel 25 that collects an exhaust gas E generated from the combustion equipment 2, 15 and supplies the exhaust gas to the gasification furnace 1, wherein the gasification system is configured to be able to control an amount of oxygen supplied to the gasification furnace 1 by supplying the exhaust gas E generated from the combustion equipment 2, 15 to the gasification furnace 1 as the gasifying agent.SELECTED DRAWING: Figure 1

Description

The present invention relates to a technique for producing gasification gas from a carbon source such as woody biomass, and more particularly to a system for controlling a gasification reaction in a gasification furnace and a method for operating such a gasification furnace.

FIG. 4 shows an example of a conventional general gasification system. Here, wood chips are used as the gas raw material M as the carbon source of the gasification gas, and the wood chips M are heated in the gasification furnace 1 together with the gasifying agent to obtain gasification gas G by thermal decomposition, and the gasification is performed. A biomass power generation system is assumed in which gas G is burned by an engine generator 2 (hereinafter, simply referred to as “generator 2”) to generate electricity.

The wood chips M are loaded from above the hopper 4 by the chip crane 3, transported to the gasifier 1 by the conveyor 5 connected to the outlet of the hopper 4, and charged into the gasifier 1.

As the gasification furnace 1, an upflow type gasification furnace is assumed here. The wood chip M as a gas raw material is charged into the gasifier 1 from the raw material input port 1a provided above, while the air A as a gasifier is charged from the gasifier supply port 1b provided below. And steam V are supplied.

The air A as the gasifying agent is sent to the gasifying furnace 1 by the blower 6 through the gasifying agent supply path 1c. The gasifier supply path 1c from the blower 6 to the gasifier supply port 1b is branched into two in the middle, and a humidifier 7 is provided in the middle of one of them. In the humidifier 7, water vapor V as a gasifying agent is added to the air A. In this way, the air A sent out from the blower 6 is supplied to the gasification furnace 1 in a state where an appropriate amount of steam V is mixed.

Of the gases (air A and steam V as gasifiers) supplied to the gasifier supply port 1b, oxygen reacts with a part of the wood chip M in the lower layer in the furnace and burns it. Due to the heat generated by combustion, a part of the components of the wood chip M is thermally decomposed to generate gasified gas containing carbon monoxide, gaseous hydrogen, methane and the like.

The generated gasification gas G is taken out from the gas outlet 1d provided in the upper part of the gasification furnace 1 and sent to the cooler 8 provided in the subsequent stage of the gasification furnace 1. With cooling, water vapor and tar contained in the gasification gas G are condensed and removed from the gasification gas G. The gasified gas G from which water vapor and tar have been removed is subsequently sent to the dust collector 9, where droplets and particles remaining in the gasified gas G are removed.

The tar T condensed by the cooler 8 and the tar T collected by the dust collector 9 are sent to the tar separator 10. The processing of tar T after being sent to the tar separator 10 will be described later.

The gasified gas G from which the tar T and particles have been removed by the cooler 8 and the dust collector 9 is sent to the generator (engine generator) 2 as a combustion facility by the fan 11. In the generator 2, the gasified gas G is burned to generate electricity, and the generated exhaust gas E flows into the exhaust flow path 12 and is discharged from the exhaust pipe 13 provided on the outlet side of the exhaust flow path 12. A heat exchanger 14 for recovering the exhaust heat of the exhaust gas E is provided in the middle of the exhaust flow path 12, and the role of the heat exchanger 14 will be described later.

In the tar separator 10, the tar T recovered in the cooler 8 and the dust collector 9 is separated by the specific gravity of the components. Of the separated tar T components, the component having a large specific gravity is sent to the tar combustion device 15. The tar combustion device 15 is a combustion facility that burns tar T as fuel.

Among the components of tar T separated by the tar separator 10, the component having a small specific gravity is sent to the light tar concentrator 16, concentrated by evaporation, and then sent to the tar combustion device 15 for combustion. The flash steam F generated at the time of concentration is heated by the steam heater 17 and then sent to the tar combustion device 15.

The above-mentioned steam heater 17 is installed in the middle of the exhaust flow path 18 through which the exhaust gas E generated in the tar combustion device 15 flows, so that the flash steam F is heated by the exhaust heat of the exhaust gas E. It has become. Further, a combustion air heater 19 is installed on the downstream side of the steam heater 17. Air for combustion of the tar T (combustion air A1) was sent to the combustion air heater 19 by the operation of the fan 20, and the combustion air A1 was heated here by the exhaust heat of the exhaust gas E. Then, it is supplied to the tar combustion device 15.

A heat exchanger 21 is provided on the downstream side of the combustion air heater 19 in the exhaust flow path 18. The heat exchanger 14 provided in the exhaust flow path 12 of the generator 2 described above and the heat exchanger 21 provided in the exhaust flow path 18 of the tar combustion device 15 are connected by a heat medium flow path 22. A heat medium H such as water circulates in the heat medium flow path 22 to recover the exhaust heat of the exhaust gas E. The heat medium flow path 22 is further connected to the light tar concentrator 16, and the waste heat recovered by the heat medium H in the heat exchangers 14 and 21 is used for concentrating the tar T in the light tar concentrator 16. It is supposed to be done.

A fan 23 is installed on the downstream side of the heat exchanger 21 in the exhaust flow path 18, and the operation of the fan 23 drives the flow of the exhaust gas E in the exhaust flow path 18. The exhaust gas E is discharged from the exhaust pipe 24 provided on the outlet side of the exhaust flow path 18.

As prior art documents related to the generation of gasified gas by such a gasification furnace, for example, there is the following Patent Document 1 and the like.

Japanese Unexamined Patent Publication No. 2005-273456

By the way, in the above-mentioned gasification system, the properties of the wood chip M used as a gas raw material, that is, the composition and water content of the organic matter which is a constituent component, vary depending on the plant species, the growing state, the storage state and the like. In particular, the water content greatly affects the amount of heat and oxygen required for the gasification process. That is, the higher the water content, the larger the amount of heat required to dry the wood chips M, and the larger the amount of oxygen that covers the amount of heat. Therefore, from the viewpoint of supplying oxygen required for gasification, the required supply amount of air A as a gasifying agent varies depending on the water content of the wood chip M.

On the other hand, at the gas outlet 1d of the gasification furnace 1, it is desirable to keep the pressure of the gasification gas G slightly lower than the atmospheric pressure. This is to minimize the possibility that external air will flow into the flow path of the gasification gas G, and to smoothly supply the gasification gas G to the generator 2 in the subsequent stage. Since it is necessary to keep the pressure constant in this way, the supply amount of air A as a gasifying agent cannot be changed so much. As a result, even when the water content of the wood chip M is low and the amount of oxygen required for gasification is relatively small, it is inevitable to supply air A that exceeds the required amount of oxygen for gasification. The excess oxygen burns the components of the wood chip M (that is, the carbon content becomes carbon dioxide instead of methane or carbon monoxide), which is one of the factors that hinder the improvement of gasification efficiency.

In view of such circumstances, the present invention is intended to provide a gasification system and a method of operating a gasification furnace capable of suitably controlling a gasification reaction.

The present invention comprises a gasification furnace that heats a gas raw material as a carbon source together with a gasifying agent to generate gasified gas, a combustion facility that burns fuel to generate exhaust gas, and an exhaust gas generated from the combustion facility. It is provided with an exhaust supply flow path for recovering gas and supplying it to the gasification furnace, and by supplying the exhaust gas generated from the combustion equipment to the gasification furnace as a gasifier, oxygen to the gasification furnace is provided. It is related to a gasification system characterized in that it is configured to be able to control the supply amount of the gas.

In the gasification system of the present invention, as the combustion equipment, an equipment for burning the gasification gas generated in the gasification furnace or a tar combustion device for burning the tar recovered from the gasification gas generated in the gasification furnace. At least one can be provided.

The gasification system of the present invention can be configured so that the supply of exhaust gas can be switched according to the water content of the gas raw material.

In the gasification system of the present invention, the water content of the gas raw material may be configured so that it can be grasped through the temperature in the gasification furnace.

In the gasification system of the present invention, the water content of the gas raw material may be configured so that it can be grasped through the composition of the gasification gas produced in the gasification furnace.

In the gasification system of the present invention, the water content of the gas raw material may be configured so that it can be grasped through the consumption amount of the gas raw material.

The gasification system of the present invention may be configured to use a raw material selected from biomass, waste, and coal as a gas raw material.

Further, the present invention recovers the exhaust gas generated from the combustion equipment that burns the fuel to the gasifier that generates the gasified gas by heating the gas raw material as a carbon source together with the gasifying agent, and the gasifying agent. The present invention relates to a method for operating a gasifier, which comprises controlling the amount of oxygen supplied to the gasifier.

In the operation method of the gasification furnace of the present invention, the combustion equipment is the equipment for burning the gasification gas generated in the gasification furnace or the tar for burning the tar recovered from the gasification gas generated in the gasification furnace. It can be at least one of the combustors.

In the operation method of the gasification furnace of the present invention, the supply of the exhaust gas can be switched according to the water content of the gas raw material.

According to the gasification system and the operation method of the gasification furnace of the present invention, an excellent effect of appropriately controlling the gasification reaction can be obtained.

It is a block diagram which shows an example of the gasification system by carrying out this invention. It is a graph which shows an example of the relationship between the water content and the consumption amount of a gas raw material in a conventional example. It is a flowchart which shows an example of the procedure of the operation method of the gasification furnace by carrying out this invention. It is a block diagram which shows an example of the general gasification system using woody biomass as a gas raw material.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 1 shows an example of the form of a gasification system according to the implementation of the present invention, and in the figure, the portions having the same reference numerals as those in FIG. 4 represent the same objects. The basic configuration is the same as that of the conventional example shown in FIG. 4, and the gasification furnace 1 that reacts the wood chip M to obtain the gasification gas G and the gasification gas G generated by the gasification furnace 1 are used as fuel. It is equipped with a generator (engine generator) 2 as a combustion facility for combustion.

The wood chips M charged into the hopper 4 by the chip crane 3 are carried by the conveyor 5 and charged into the raw material charging port 1a of the gasification furnace 1. The air A and the steam V as the gasifying agent are supplied from the gasifying agent supply port 1b provided below the gasification furnace 1. The air A as the gasifying agent is sent from the gasifying agent supply port 1b through the gasifying agent supply path 1c by the blower 6. Water vapor V as a gasifying agent is added to the air A as needed by a humidifier 7 provided in the middle of the gasifying agent supply path 1c.

A part of the oxygen contained in the air A as a gasifying agent burns a part of the wood chip M in the lower part of the furnace, and the combustion heat generated at that time causes a part of the components of the wood chip M to be a gasifying agent. It is heated together with it and pyrolyzed to generate gasification gas G. The gasified gas G is taken out from the gas outlet 1d provided in the upper part of the gasification furnace 1 and sent to the cooler 8 in the subsequent stage to remove the tar T. The gasified gas G from which the tar T has been removed is subsequently sent to the dust collector 9, and the remaining tar T and particles are removed. The tar T condensed by the cooler 8 and the tar T collected by the dust collector 9 are sent to the tar separator 10.

The gasified gas G from which the tar T and particles have been removed by the cooler 8 and the dust collector 9 is sent to the generator 2 as a combustion facility by the fan 11 and burned. The generated exhaust gas E flows into the exhaust flow path 12, and is discharged from the exhaust pipe 13 provided on the outlet side of the exhaust flow path 12.

In the tar separator 10, the tar T recovered from the gasified gas G by the cooler 8 and the dust collector 9 is separated by the specific gravity of the components, and the components having a large specific density are sent to the tar combustion device 15 as a combustion facility for combustion. Will be done. The component having a low specific density is sent to the light tar concentrator 16, concentrated, and then sent to the tar combustion device 15 for combustion. The flash steam F generated at the time of concentration is heated by the steam heater 17 and then sent to the tar combustion device 15.

A steam heater 17 is installed in the middle of the exhaust flow path 18 through which the exhaust gas E generated by the tar combustion device 15 flows, and the flash steam F is heated by the exhaust heat of the exhaust gas E here. A combustion air heater 19 is installed on the downstream side of the steam heater 17, and the combustion air A1 is sent by the operation of the fan 20, heated by the exhaust heat of the exhaust gas E, and then tar. It is designed to be supplied to the combustion device 15.

Heat exchangers 14 and 21 are provided in the middle of the exhaust flow path 12 and at positions on the downstream side of the combustion air heater 19 in the exhaust flow path 18, respectively. The heat exchanger 14 and the heat exchanger 21 are connected by a heat medium flow path 22, and a heat medium H such as water circulates in the heat medium flow path 22. The heat medium flow path 22 is further connected to the light tar concentrator 16, and the waste heat recovered by the heat medium H in the heat exchangers 14 and 21 is used for concentrating the tar T in the light tar concentrator 16. It is supposed to be done.

A fan 23 is installed on the downstream side of the heat exchanger 21 in the exhaust flow path 18, and the operation of the fan 23 drives the flow of the exhaust gas E in the exhaust flow path 18. The exhaust gas E is discharged from the exhaust pipe 24 provided on the outlet side of the exhaust flow path 18.

The above configuration is common to the conventional example shown in FIG. 4, but in the case of this embodiment shown in FIG. 1, the exhaust supply flow path 25 is connected to the exhaust flow paths 12 and 18, and the exhaust supply flow path 25 is connected. It is characterized in that it is configured so that the exhaust gas E can be recovered from the gasifier 1 and supplied to the gasifier 1 as a gasifying agent.

The inlet side of the exhaust flow path 25 is connected to the position between the heat exchanger 14 and the exhaust stack 13 in the exhaust flow path 12, and is connected to the position between the fan 23 and the exhaust stack 24 in the exhaust flow path 18. Each of the exhaust supply flow paths 25 joins each other on the downstream side thereof. The outlet side of the exhaust supply flow path 25 is connected to the gasifier supply path 1c. An on-off valve 26 is provided in the middle of the exhaust gas supply flow path 25 so that the exhaust gas supply flow path 25 can be opened and closed. In this way, the exhaust gas E can be introduced into the air A flowing through the gasifier supply path 1c as needed.

The connection position of the exhaust supply flow path 25 with respect to the gasifier supply path 1c may be the upstream side (indicated by a solid line in the figure) or the downstream side (indicated by a broken line in the figure) of the blower 6. When the exhaust gas supply flow path 25 is connected to the downstream side of the blower 6, it is preferable to provide a fan 27 in the middle to pressurize the exhaust gas E and send it to the gasifier supply path 1c.

In this way, for example, when the water content of the wood chip M is high, only air A (or air A and steam V) is supplied to the gasifier 1 as a gasifying agent, and the water content of the wood chip M is low. In this case, it is possible to control the amount of oxygen supplied to the gasifier 1 by operating such that air A as a gasifying agent is mixed with exhaust gas E having a small amount of oxygen and supplied. The oxygen concentration in the air A is generally about 21%, but the oxygen concentration in the exhaust gas E discharged from the generator 2 is, for example, about 10%, and the oxygen concentration in the exhaust gas E discharged from the tar combustion device 15 is about 10%. The oxygen concentration is, for example, about 4 to 5%. By recovering the exhaust gas E having a low oxygen concentration and supplying it to the gasifier 1 as a gasifier, the total volume and pressure of the supplied gasifier do not fluctuate significantly, and therefore the gasifier. The amount of oxygen supplied can be adjusted without greatly changing the pressure in 1.

FIG. 2 shows the relationship between the water content of the wood chip M and the consumption amount of the wood chip M in the conventional example shown in FIG. The solid line in the figure shows the theoretical value when gasification is performed by adding an amount of oxygen required for gasification according to the water content of the wood chip M when generating power at the rated output. Considering the consumption of the wood chip M to cover the required power generation in the generator 2, the higher the water content of the wood chip M, the larger the daily consumption weight of the wood chip M (carbon for evaporation of water). It is theoretically considered that the lower the water content, the smaller the weight consumed per day (because it requires the combustion of minutes).

On the other hand, the broken line in the figure shows the relationship between the water content and the consumption of the wood chip M when power is generated at the rated output in the actual equipment. Compared with the theoretical value shown by the solid line, the consumption of the wood chip M is high in the region where the water content is low. This is as explained above, even though a small amount of wood chip M should be able to produce the required gasification gas G if only the amount of oxygen required for gasification is supplied. As a result of the surplus air A being supplied for the purpose of maintaining pressure, the carbon content that could theoretically be used as a gasification gas is burned by the oxygen contained in the surplus air A and becomes carbon dioxide. It means that you are.

Therefore, if the exhaust gas E having a small amount of oxygen is used as the gasification gas as in the present embodiment shown in FIG. 1, the total amount of the gasifying agent supplied into the gasifier 1 does not change significantly, and the gas does not change significantly. It is possible to bring the oxygen supply amount close to an appropriate value while keeping the pressure at the gas outlet 1d of the gas outlet 1d close to the atmospheric pressure, thereby improving the gasification efficiency when the water content of the wood chip M is low. Can be done.

Here, in order to perform the above-mentioned operation, it is desirable to grasp the water content of the wood chip M in some form. A few examples of specific methods for this will be described below.

For example, as shown by the reference numeral 28 in the figure, the gasification furnace 1 is provided with a temperature sensor as a water content monitoring unit, and the water content of the wood chip M can be grasped through the temperature inside the furnace. Here, a case where a plurality of temperature sensors 28 are attached to different height positions in the furnace is illustrated. In the case of the upflow type gasifier 1, a gasifying agent containing oxygen is supplied from below, and combustion by oxygen occurs in the lower layer of the wood chip M, so that the temperature inside the furnace is the highest at the bottom and above that. It gets lower as you go toward. Here, when the water content of the wood chip M is high, the heat generated by combustion at the lowermost part is quickly taken away by the evaporation of water as it is transferred upward, so that the temperature is in the region slightly above the lowermost part. Will drop significantly. On the other hand, when the moisture content of the wood chip M is low, the amount of heat used for drying is small, and the high temperature region continues widely to a relatively upper position. From such a difference in temperature distribution, it is possible to grasp the high and low water content of the wood chip M to some extent. Instead of such a temperature distribution, the water content of the wood chip M may be grasped from the temperature at a certain point, the average value of the temperatures measured at a plurality of positions, and the like.

Alternatively, the water content of the wood chip M can be grasped by measuring the composition of the gasification gas G generated from the wood chip M. When gas is used as fuel in a facility such as a power plant, it is generally performed to sample a part of the fuel gas and analyze the composition for the purpose of grasping the amount of heat generated by combustion. FIG. 1 illustrates a sampling unit 29 for analyzing the gasified gas G as a water content monitoring unit. In the sampling unit 29, a part of the gasified gas G from which the tar T and particles have been removed by the dust collector 9 is extracted as the sampling gas S, and various methods (for example, a non-dispersed infrared absorption method or a magnetic oxygen concentration meter are used). The composition has come to be analyzed using the method used. From the result of the composition analysis of the sampling gas S, the water content of the wood chip M can be grasped.

Alternatively, the water content of the wood chip M can also be grasped from the consumption amount of the wood chip M which is a gas raw material. For example, as shown by the theoretical value shown by the solid line in FIG. 2, the amount of the gas raw material (wood chip M) required to cover a certain amount of heat by the gasification gas G increases as the water content increases. Therefore, for example, in the chip crane 3 shown in FIG. 1, the consumption amount of the wood chip M as a gas raw material is monitored (in this case, the chip crane 3 plays a role as a raw material consumption monitoring unit). In the chip crane 3, the amount of wood chips M put into the hopper 4 at a certain time zone can be grasped as the consumption amount. If the consumption of the wood chip M is larger than the power generation amount of the generator 2 in the subsequent stage, it can be determined that the water content of the wood chip M is high.

Of course, as a more direct method, a manual analysis method in which the wood chips M are periodically sampled and dried and the water content is grasped from the weight difference before and after drying is also possible.

In addition, various methods can be considered as a method for grasping the water content of the wood chip M. As the principle for grasping the water content and the configuration of the water content monitoring unit, an appropriate principle and configuration can be adopted as long as the water content can be grasped. Further, a plurality of types of devices and equipment may be used in combination as the water content monitoring unit.

In operating the introduction of the exhaust gas E as a gasifying agent based on the water content grasped in this way, for example, this can be performed based on human judgment. According to the water content of the wood chip M grasped by the water content monitoring units 28 to 30, a person determines whether or not to reduce the amount of oxygen supplied to the gasifier 1, and if the water content is high, the on-off valve is used. 26 is closed and only air A or air A and steam V are supplied to the gasifier 1 as a gasifying agent, while the on-off valve 26 is opened (and the fan 27 is operated) when the water content is low. ), Exhaust gas E is introduced into the gasification furnace 1 as a gasifying agent.

In such an operation, for example, a certain threshold value is set for the water content, the on-off valve 26 is closed when the grasped water content is equal to or higher than the threshold value, and the on-off valve 26 is opened when the water content is lower than the threshold value. Alternatively, the opening degree of the on-off valve 26 may be adjusted according to the magnitude of the numerical value of the water content. In this way, by changing the presence / absence or supply amount of the exhaust gas E as the gasifying agent according to the water content of the gas raw material M, it is possible to optimize the gasification reaction according to the water content. ..

Further, the grasped water content of the wood chip M and the opening / closing of the on-off valve 26 may be automatically linked. For example, as shown in FIG. 1, the water content grasped by the water content monitoring units 28 to 30 is input to the control device 31, and the control device 31 opens / closes and opens the on-off valve 26 according to the input water content. It can also be configured to manipulate the degree.

The operation method of the gasification furnace in the gasification system as described above can be summarized in a flowchart as shown in FIG. 3, for example.

First, the water content of the wood chip M, which is a gas raw material, is grasped (step S1). As described above, the water content can be grasped by at least one of the water content monitoring units 3, 28, 29, or by manual analysis or the like. Subsequently, the system operator or the control device 31 determines whether or not the grasped water content is high (step S2). Here, for example, the water content of the wood chip M grasped by a certain water content monitoring unit, or some numerical value reflecting the water content (temperature in the gasifier 1, the ratio of water in the sampling gas S, consumption of the wood chip M). The determination may be made based on whether or not the amount, etc.) exceeds a certain threshold value, and as described above, the high or low water content is determined based on the temperature distribution in the gasifier 1. You can also do it.

When it is determined that the water content of the wood chip M is low, the on-off valve 26 is opened and the exhaust gas E is supplied to the gasifier 1 as a gasifying agent from the exhaust supply flow path 25 (step S3). Here, the supply amount of the exhaust gas E may be further adjusted according to the level of the water content.

If it is determined in step S2 that the water content is high, the on-off valve 26 is closed and only a gas other than the exhaust gas E (air A or water vapor V) is supplied as a gasifying agent (step S4). By operating the gasification furnace 1 while repeating this step, it is possible to supply an appropriate amount of oxygen for gasification of the wood chip M without significantly changing the pressure in the gasification furnace 1.

Although a case where wood chips are used as a gas raw material has been described here as an example, the present invention is not limited to this. The present invention can be applied to various gasification systems as long as a gasification furnace capable of using substances having different water contents as a gas raw material is provided. That is, the gas raw material may be a raw material containing biomass other than wood chips (for example, garbage) or a substance other than biomass, for example, coal.

Further, here, as a combustion facility, a case where a generator 2 which is an engine generator that burns gasified gas G and a tar combustion device 15 that burns tar T is provided is illustrated, but the combustion facility is used in these facilities. Not limited. Any device or equipment that generates an exhaust gas that can be used as a gasifying agent, that is, an exhaust gas having a lower oxygen content than air, can be used for carrying out the present invention regardless of its type and configuration. .. However, if the above-mentioned combustion equipment (generator 2 or tar combustion device 15) that burns the gasification gas G or tar T generated in the gasification furnace 1 as fuel is used as a supply source of exhaust gas, it is gasified. Since the gasification furnace 1 as a supply destination of the exhaust gas E as an agent also functions as a supply source of fuel (gasification gas G and tar T) to the combustion equipment, the entire gasification system The configuration can be made compact. In this embodiment, the case where the generator 2 and the tar combustion device 15 are used as the combustion equipment that is the supply source of the exhaust gas E has been described, but only the exhaust gas E generated from one of these is used as the gasifying agent. It may be supplied to the gasification furnace 1.

Further, although the upflow type gasification furnace 1 is exemplified as the gasification furnace, the present invention can also be applied to the downdraft type gasification furnace. However, in general, in a downdraft type gasification furnace, the gas raw material is dried to some extent in advance and then put into the gasification furnace, so that the fluctuation of the water content of the gas raw material is not as large as in the case of the upflow type gasification furnace. The action and effect of the present invention can be exhibited more remarkably when applied to an upflow type gasification furnace in which the water content of the gas raw material fluctuates greatly, as in the above-described embodiment.

As described above, in the gasification system of the present embodiment, the gas raw material (wood chip) M as a carbon source is heated together with the gasifier (air A, steam V) to generate gasification gas G. The furnace 1, the combustion equipment (generator 2, tar combustion device 15) that burns fuel (gasified gas G, tar T) to generate exhaust gas E, and the exhaust gas E generated from the combustion equipments 2 and 15. It is provided with an exhaust supply flow path 25 that collects and supplies the exhaust gas to the gasifier 1, and supplies the exhaust gas E generated from the combustion facilities 2 and 15 to the gasifier 1 as a gasifier to the gasifier 1. It is configured to be able to control the amount of oxygen supplied to the vehicle.

Further, in the operation method of the gasification furnace of the present embodiment, the fuel G is compared with the gasification furnace 1 which heats the gas raw material M as a carbon source together with the gasifiers A and V to generate the gasification gas G. , The exhaust gas E generated from the combustion equipments 2 and 15 that burn T is recovered and supplied as a gasifying agent to control the amount of oxygen supplied to the gasification furnace 1.

By doing so, it is possible to adjust the amount of oxygen supplied to the gasification furnace 1 without significantly changing the pressure in the gasification furnace 1.

Further, in the gasification system of the present embodiment, as the combustion equipment, the equipment for burning the gasification gas G generated in the gasification furnace 1 (generator 2) or the gasification gas G generated in the gasification furnace 1 is used. It is provided with at least one of the tar combustion devices 15 (both in this embodiment) for burning the recovered tar T.

Further, in the operation method of the gasification furnace of the present embodiment, the combustion equipment is the equipment for burning the gasification gas G generated in the gasification furnace 1 (generator 2) or the gasification generated in the gasification furnace 1. At least one of the tar combustion devices 15 (both in this embodiment) for burning the tar T recovered from the gas G.

By doing so, the gasifier 1 as a supply destination of the exhaust gas E as a gasifying agent also functions as a supply source of fuel (gasified gas G or tar T) to the combustion equipment. , The overall configuration of the gasification system can be made compact.

Further, the gasification system of the present embodiment is configured to be able to switch the supply of the exhaust gas E to the gasification furnace 1 according to the water content of the gas raw material M.

Further, in the operation method of the gasification furnace of this embodiment, the supply of the exhaust gas E to the gasification furnace 1 is switched according to the water content of the gas raw material M.

By doing so, the supply amount of the exhaust gas E as the gasifying agent can be changed according to the water content of the gas raw material M, and the gasification reaction can be optimized according to the water content of the gas raw material M. ..

Further, in the gasification system of the present embodiment, the water content of the gas raw material M can be configured so as to be grasped through the temperature in the gasification furnace 1.

Further, in the gasification system of the present embodiment, the water content of the gas raw material M can be configured so that it can be grasped through the composition of the gasification gas G generated in the gasification furnace 1.

Further, in the gasification system of the present embodiment, the water content of the gas raw material M can be configured so as to be grasped through the consumption amount of the gas raw material M.

Further, in the gasification system of this embodiment, a raw material selected from biomass, waste, and coal (wood chips in this example) is used as the gas raw material M. By doing so, in a gasification system using biomass as the gas raw material M, the above-mentioned action and effect can be obtained.

Therefore, according to the present embodiment, the gasification reaction can be suitably controlled.

The gasification system and the operation method of the gasification furnace of the present invention are not limited to the above-described embodiment, and it is needless to say that various changes can be made without departing from the gist of the present invention. ..

1 Gasification furnace 2 Combustion equipment (generator)
15 Combustion equipment (tar combustion equipment)
25 Exhaust supply flow path A Gasifier (air)
G gasification gas T tar M gas raw material (wood chips)
V gasifying agent (water vapor)

Claims (10)

A gasifier that heats a gas raw material as a carbon source together with a gasifying agent to generate gasified gas,
Combustion equipment that burns fuel to generate exhaust gas,
It is provided with an exhaust supply flow path that collects the exhaust gas generated from the combustion equipment and supplies it to the gasification furnace.
A gasification system characterized in that the amount of oxygen supplied to the gasification furnace can be controlled by supplying the exhaust gas generated from the combustion facility as a gasifying agent to the gasification furnace. .. The combustion facility is characterized by including at least one of a facility for burning the gasification gas generated in the gasification furnace and a tar combustion device for burning the tar recovered from the gasification gas generated in the gasification furnace. The gasification system according to claim 1. The gasification system according to claim 1 or 2, wherein the supply of the exhaust gas can be switched according to the water content of the gas raw material. The gasification system according to claim 3, wherein the water content of the gas raw material can be grasped through the temperature in the gasification furnace. The gasification system according to claim 3, wherein the water content of the gas raw material can be grasped through the composition of the gasification gas produced in the gasification furnace. The gasification system according to claim 3, wherein the water content of the gas raw material can be grasped through the consumption amount of the gas raw material. The gasification system according to any one of claims 1 to 6, wherein the gasification system is configured to use a raw material selected from biomass, waste, and coal as a gas raw material. For a gasifier that produces a gasified gas by heating a gas raw material as a carbon source together with a gasifying agent.
A method for operating a gasifier, which comprises controlling the amount of oxygen supplied to the gasifier by recovering exhaust gas generated from a combustion facility that burns fuel and supplying it as a gasifying agent. The combustion facility is characterized in that it is at least one of a facility for burning the gasification gas generated in the gasification furnace and a tar combustion device for burning the tar recovered from the gasification gas generated in the gasification furnace. The method for operating the gasifier according to claim 8. The method for operating a gasifier according to claim 8 or 9, wherein the supply of exhaust gas is switched according to the water content of the gas raw material.

Images