JP2002275479A - Method and apparatus for combustible gas production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide both a method for a combustible gas production, with which a gas having a high calorific value can be recovered, a cost required for gas for miscellaneous uses such as air current transportation, etc. and wasteful energy consumption can be reduced, and also provide an apparatus therefor. SOLUTION: A CO-containing combustible gas is generated in a waste gasification furnace 10 being a gas generation means. A part or the whole of CO2 is separated from the generated combustible gas in a separation column 40. The separated CO2 gas is supplied as a gasification agent (reactant gas) from a carbon dioxide gas holder 45 to the gasification furnace 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to various gas generating means for generating a combustible gas containing carbon monoxide, such as a gasifier for gasifying waste or coal and various iron making facilities. The present invention relates to a method and an apparatus for producing a combustible gas which optimizes generation and use of the gas.

[0002]

2. Description of the Related Art A waste gasifier is an apparatus for producing a combustible gas such as carbon monoxide (CO) and hydrogen (H ₂ ) from a combustible waste containing a carbon compound as a raw material. That is, basically, waste is converted into an easily combustible gas using a chemical reaction such as 2C + O ₂ → 2CO or C + H ₂ O → CO + H ₂ . For example, Japanese Unexamined Patent Application Publication No.
The gasification furnace (gasification device) described in Japanese Patent Publication No. 60 also converts waste plastic into fuel gas or the like. Means for generating flammable gas from carbon compounds in the same manner include coal gasification facilities, and also blast furnaces, converters,
There are iron making facilities such as smelting reduction furnaces and coke ovens.

[0003] The combustible gas generated in such furnaces and equipment is recovered and used as various energy sources. For example, it is stored as fuel for various uses, or is immediately burned and used for energy recovery in a boiler or gas turbine.

[0004]

The production of combustible gas by gas generating means such as a waste gasifier has room for improvement in efficiency and cost in the following points. Was.

B) The amount of heat generated per unit volume of the gas to be recovered is often not sufficiently high. The flammable gas generated is CO or H _{2, which} is the center of the flammable component, contains almost no hydrocarbons having a high calorific value such as propane and butane, and has carbon dioxide gas (CO ₂ ) and nitrogen (N ₂ ) Is contained in a considerable amount. Therefore, in order to secure a necessary amount of heat, a considerably large capacity is required as a gas storage means or the like, and disadvantages arise in installation space and equipment costs.

(B) An inert gas such as N ₂ must be prepared as a miscellaneous gas used for various purposes in a means for generating combustible gas or a passage of the gas. The miscellaneous gas includes, for example, a raw material that is transported by air flow (powder or the like is pushed in by a gas pressure in a pipe or the like) or a small opening is sealed to prevent the inflow of outside air (by blowing out N ₂ to inflow of outside air). Or a gas used for cleaning attached substances (removing adhered powder or the like by spraying a gas). If air is used as such a miscellaneous gas in a portion where a high-temperature flammable gas exists, the flammable gas may be burned. Generally, an inert gas such as N ₂ is used,
The gas must be purchased or produced separately from the air, which can be costly or consume considerable energy. Since the gas such as N ₂ used in the chore will be mixed into the combustible gas, it becomes possible to calorific value of the combustible gas to be recovered is further reduced.

(C) When the produced gas is used under pressure, wasteful energy is partially consumed. This is because when gas is sent to a gas turbine or the like for power generation, it is necessary to pressurize CO ₂ , which is a non-combustible component, when compressing the gas, which requires extra pressurizing power. Consuming wasteful energy in this way goes against the essential purpose of the combustible gas production process, namely, efficient use of energy.

[0008] In view of the above, the claimed invention makes it possible to recover a gas having a high calorific value, reduce the cost required for a chore gas, or reduce unnecessary energy consumption. It is an object of the present invention to provide a manufacturing method and apparatus.

[0009]

According to a first aspect of the present invention, there is provided a method for producing a flammable gas, wherein a flammable gas containing CO is generated in a gas generating means, and CO ₂ is generated from the flammable gas.
(Part or all) of the gas and its separated CO
It is characterized in that _two gases are supplied to the above gas generating means as a gasifying agent (reactive gas). As the "gas generating means", for example, a waste gasifier, a coal gasifier, or the above-mentioned steelmaking equipment such as a blast furnace, a converter, a smelting reduction furnace, and a coke oven can be used (also in the following claims). The same is true). The remaining gas from which the CO ₂ gas is separated out of the generated combustible gas is recovered and stored in a gas holder, for example, or supplied to a gas turbine for power generation. In order to separate the CO ₂ gas from the combustible gas, for example, a chemical substance having a CO ₂ gas adsorption performance such as an amine-based solid absorbent, zeolite, or activated carbon can be used.

The method of producing a combustible gas has the following effects. First, since CO ₂ is separated from the generated combustible gas and the remainder is recovered, the calorific value per unit volume of the recovered gas is increased and the value of the recovered gas becomes high. This is because the ratio of CO and H ₂ , which are flammable components, increases when CO _2, which is a non-combustible component, decreases. Since the same amount of recovered gas can have high energy, there is also an advantage that the required capacity of the gas holder (storage means) can be reduced.

Further, since the separated CO ₂ gas is supplied to the gas generating means as a gasifying agent, the amount of CO in the combustible gas can be increased at the time of generation. The amount can be even higher. CO can be increased by supplying CO ₂ gas as a gasifying agent to the gas generating means because the CO ₂ gas reacts with carbon (C) in an unreacted substance (a substance that has not been gasified). Then, it is changed to CO by C + CO ₂ → 2CO.

The method for producing a flammable gas according to claim 2 is a waste gas that gasifies waste to generate the flammable gas (ie, one containing CO) as the gas generating means. It is characterized by using a gasification furnace. "Waste" includes waste plastic, garbage, wood chips,
Various general wastes and industrial wastes such as paper waste are included, and various gasification furnaces such as a spouted bed type, a kiln type, a fluidized bed type, and a compost type can be used as a means for gasifying them.

[0013] Also in this method using a waste gasifier, a flammable gas having a large amount of CO gas and a high calorific value per unit volume is recovered by the above-described operation. However, this method of separating CO ₂ gas (separation from combustible gas) and supplying CO ₂ gas (supplying gas as a gasifying agent to a gas generating means) as described above in relation to a waste gasifier is particularly advantageous. Is big. In other words, since waste has a large component variation, it is difficult to constantly control the generation of CO _{2 in} a waste gasifier even if the operating conditions are precisely controlled. Therefore, if the CO ₂ gas is separated from the generated gas and supplied to the gasifier again as a gasifying agent, the content ratio of the CO ₂ gas can be surely reduced without the need for costly and complicated advanced control. It is.

The method for producing a flammable gas according to claim 3 further comprises obtaining steam by the retained heat (waste heat) of the generated flammable gas, and using the steam together with the CO ₂ gas separated as a gasifying agent. The gas is supplied to the above gas generating means.

According to this method, water vapor is supplied to the gas generating means together with CO ₂ gas as a gasifying agent.
It becomes possible to further increase the combustible components in the combustible gas generated. This is because, when steam is supplied to the gas generating means as a gasifying agent, CO and H ₂ can be generated as C + H ₂ O → CO + H ₂ by reaction with C in the unreacted material. The non-combustible components, CO _2, are reduced, and the combustible components, CO and H ₂
Therefore, the calorific value per unit volume of the combustible gas naturally increases. Since the steam to be supplied as the gasifying agent is generated by the retained heat of the flammable gas as described above, no additional energy is required for the supply thereof, and the cost required for the supply is also minimized.

The method for producing a combustible gas according to claim 4 generates a combustible gas CO content in the gas generating means, to separate the generated combustible gas from the CO ₂ gas separated the CO ₂ gas Is used as a miscellaneous gas (for example, a gas for conveying airflow, a gas for sealing, or a gas for cleaning) in the gas generation means or the passage of the gas.

In the gas generating means and the passage of the flammable gas, it is often necessary to use a low-activity miscellaneous gas for airflow transport, sealing, cleaning, etc. There is no need to separately manufacture or purchase N ₂ gas or the like as such a chore gas. This is because the CO ₂ gas separated from the generated combustible gas is used as a waste gas. Since CO ₂ has a low activity and there is no danger of burning the gas even if it is blown into a high-temperature flammable gas, it can be used in a gas generating means or a passage of the gas in the same manner as the conventionally used N ₂ gas. Can be used. In addition, unlike N ₂ gas blown from the outside, C
O ₂ gas is originally contained in the flammable gas and can be separated from the flammable gas again on the downstream side, so that the calorific value of the flammable gas collected on the downstream side is reduced. No disadvantages. It is to be noted that obtaining CO ₂ gas from the generated combustible gas can be performed relatively easily using a small amount of energy, and also has a disadvantage that the remaining separated gas (combustible gas, which has many uses) can be left behind. Not with.

The method for producing a flammable gas according to claim 5, further comprising using the separated CO ₂ gas as a miscellaneous gas as described above and simultaneously using the gas generating means as a gasifying agent (reactive gas). Is supplied.

In this way, there is no need to separately manufacture or purchase a gas for use in airflow or for sealing, etc., and at the same time, the flammable amount of CO gas is high and the heat generation per unit volume is high. Gas can be recovered. In other words, it is possible to obtain a desirable combustible gas having a high calorific value, and at the same time, to reduce the energy and cost required for obtaining the chore gas.

[0020] The method for producing a combustible gas according to claim 6 is the method according to claim 4 or 5, wherein, as the gas generating means, gasification of waste to generate the above combustible gas is performed. Using a furnace, the separated CO ₂ gas is
It is characterized in that it is used as a gas for airflow transport for introducing waste into the gasification furnace.

As described above, the separation of CO ₂ gas from the combustible gas generated by the gas generating means into a gas for use as a waste gas has the advantage of eliminating the need to obtain N ₂ gas or the like. However, when the gas generating means is a waste gasifier as in the method of the present invention, the separated CO ₂ gas may be used as the gas for carrying the air stream for charging the waste as described above. Particularly preferred. This is because, unlike coal and the like, wastes to be put into the gasification furnace include those that cannot be put into the furnace by natural fall (gravity input) because they are extremely lightweight. In such waste, regardless of gravity, also if the CO ₂ gas instead of air introduced by using a pneumatic conveying, can be reliably reach the interior of the gasification furnace is not completely burned, moreover In addition, a flashback phenomenon in which the flame flows backward along the charging path can be prevented.

According to a seventh aspect of the present invention, there is provided a method for producing a flammable gas, comprising: generating a CO-containing flammable gas in a gas generating means; separating CO ₂ gas from the generated flammable gas; Gas is pressurized and supplied to a gas turbine or gas engine for power generation.

According to this method, when a combustible gas is supplied to a gas turbine or a gas engine for power generation, less power is required for pressurizing the gas. C which is a non-combustible component
This is because the O ₂ gas is separated from the flammable gas and the separated flammable gas is pressurized so as to be supplied to a gas turbine or the like. Since unnecessary pressurizing power is not consumed (or its consumption is small) for the CO ₂ gas which is not directly connected to the output of the gas turbine or the like, the power required for pressurizing can be reduced. If the pressurizing power can be reduced in this way, much of the energy of the combustible gas produced can be effectively used as electric energy.

The method for producing a flammable gas according to claim 8 is the method according to claim 7, further comprising: supplying the separated CO ₂ gas as a gasifying agent to the gas generating means; It is characterized in that it is used as a gas for use in the gas generating means or the passage of the gas.

In this way, it is possible to a) recover a desirable combustible gas having a high calorific value per unit volume, b) reduce the energy and cost required for obtaining a chore gas, c)
In addition, there is an advantage that energy consumption can be reduced by reducing the pressurizing power of gas supplied to the gas turbine for power generation and the like. The advantage of a) is that the separated CO ₂ gas is supplied as a gasifying agent to the gas generating means, and the advantage of b) is that
_{This is because the two} gases are used as miscellaneous gases in the gas generating means and the like. The advantage of c) is that the remaining combustible gas from which the CO ₂ gas has been separated is pressurized and supplied to a gas turbine or the like for power generation.

According to a ninth aspect of the present invention, there is provided an apparatus for producing a combustible gas, wherein a CO ₂ gas separating means is disposed in a gas path following the gas generating means for generating a CO-containing combustible gas, and the CO ₂ gas is separated in the separating means. _{The two} gas outlets are connected via a pressurizing means to the reaction chamber of the gas generating means.

According to this production apparatus, the method for producing a combustible gas described in claim 1 can be implemented. The CO ₂ gas (all or a part of) in the combustible gas generated by the gas generating means was separated by the CO ₂ gas separating means and discharged from the outlet, and the pressure was increased by the pressurizing means. This is because the gas is supplied as a gasifying agent (reactive gas) to the reaction chamber of the gas generating means. Claim 1
Since the method of (1) can be carried out, it is possible to produce a desirable combustible gas having a large amount of CO and a high calorific value per unit volume.

[0028] In the apparatus for producing combustible gas according to claim 10, a boiler (waste heat boiler) is further arranged in a gas path following the combustible gas generating means, and the boiler is used to generate gas in the gas generating means. A steam pipe is connected to the reaction chamber. In such an apparatus, since the steam obtained by the retained heat of the generated combustible gas can be supplied to the gas generating means as a gasifying agent together with the separated CO ₂ gas, the production method according to claim 3 is performed. Becomes possible. Therefore, the CO gas and the H ₂ gas are increased in the flammable gas, so that the calorific value per unit volume of the flammable gas can be increased. The cost of generating steam is also low.

In the apparatus for producing a flammable gas according to the eleventh aspect, a CO ₂ gas separating means is disposed in a gas path following a gas generating means for generating a CO-containing flammable gas, and the CO ₂ gas in the separating means is provided. _{(2) The} gas outlet is connected to a gas holder which can be taken out at any time via a pressurizing means and a drying means.

According to this apparatus, the manufacturing method described in claim 4 can be appropriately performed. From the gas holder provided via the pressurizing means, CO ₂ separated from the combustible gas
This is because the gas can be taken out at any time and the CO ₂ gas can be used as a gas for transportation, sealing or cleaning in the gas generating means or the passage of the gas. Therefore, as described above, there are advantages that it is not necessary to separately obtain N ₂ gas or the like as a chore gas, and that the calorific value of the recovered combustible gas is not reduced. CO ₂ from combustible gas
It is also easy to obtain the gas separately.

According to a twelfth aspect of the present invention, there is provided an apparatus for producing a flammable gas, wherein a separating means for a CO ₂ gas is disposed in a gas path following the gas generating means for generating a flammable gas containing CO, An outlet of the remaining gas is connected to a gas turbine or a gas engine for power generation via a pressurizing means. According to such an apparatus, the method according to claim 7 can be carried out. Therefore, as described above, when supplying a combustible gas to a gas turbine for power generation or the like, the power required for pressurizing the gas is reduced. It is possible to use much of the recovered gas energy effectively.

The apparatus for producing flammable gas according to claim 13 is the apparatus according to claim 12, further comprising an outlet for CO ₂ gas in the above-mentioned separation means via a pressurizing means. It is characterized in that it is connected to a possible gas holder, and that the gas holder is connected to a reaction chamber in the above-mentioned gas generating means.

With this manufacturing apparatus, the manufacturing method described in claim 8 can be implemented. Because the outlet of the CO ₂ gas in the separation means is connected to the gas holder, the CO ₂ gas stored in the holder can be used as needed as a gas generating means or as a chore gas in a passage of the gas, Because the holder is connected to the reaction chamber of the gas generating means, the CO ₂ gas can be supplied to the gas generating means as a gasifying agent. Since such a method can be carried out, a) a combustible gas having a high calorific value can be recovered, b) energy and cost required for obtaining a utility gas can be reduced, and c) a gas required for a gas turbine for power generation and the like can be reduced. The pressurizing power can be reduced, which is a very favorable effect on energy recovery.

In the apparatus for producing a flammable gas according to the present invention, a plurality of containers containing an amine-based solid absorbent or a liquid absorbent are arranged in parallel as the separation means, A boiler (waste heat boiler) is arranged in a gas path that follows from the generation means (follows the downstream side), and a steam pipe is connected from the boiler to the container.

With the apparatus configured as described above, it is possible to smoothly carry out the separation of CO ₂ from the combustible gas and the sending of the CO ₂ gas and the remaining gas to different paths. The combustible gas generated by the gas generating means is passed through any one of the plurality of containers described above so that CO ₂ in the gas is adsorbed by the absorbent in the container and separated from the remaining gas. This is because the operation of desorbing the adsorbed CO ₂ and regenerating the adsorption performance of the absorbent can be performed by passing steam from the waste heat boiler through another of the plurality of containers. If the container through which combustible gas is passed and the container through which steam is passed can be appropriately switched, simultaneous separation and supply of CO ₂ as described above can be performed continuously for a long period of time. In other words, this device adsorbs CO ₂ at a relatively low temperature and desorbs the CO ₂ when heated by steam or the like to regenerate the adsorption performance, which is the characteristic of amine-based solid or liquid absorbents. It can be said that energy recovery of waste gasification gas can be realized in a preferable mode by utilizing it properly.

[0036]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a system diagram of an apparatus for producing a combustible gas by gasification of waste as an embodiment of the present invention.

The basic process in the illustrated apparatus is as follows. First, the combustible waste is gasified in the gas generating means 1 including the gasifier 10, and CO and H
Generates flammable gases including ₂ . The generated combustible gas is passed through a waste heat boiler 20, dust-removed, neutralized, washed, etc. in a refining unit 30, and collected in a collecting unit 50 to be used as a fuel for a power generation gas turbine (not shown). Store in compressed state. Except for the part to be compressed (pressurized), the whole process is operated at atmospheric pressure.

In this manufacturing apparatus, the gas generating means 1
The raw material hopper 2 and the gasification furnace 10 are main components. The hopper 2 receives the crushed and dried waste from the upper part, and can quantitatively cut it out from the lower cut-out valve 2a (such as a screw pump or a rotary valve). While one of the two (or more) hoppers 2 is receiving the waste, the other hopper 2 can send the waste toward the gasifier 10. Gasifier 10
Is a spouted bed type having a precombustor 11 and a partial combustion gasification / ash melting furnace 12 as main parts. The waste sent from the raw material hopper 2 is introduced into the pre-combustor 11 by air flow, and is simultaneously pre-combusted by oxygen (O ₂ ) blown from the oxygen tank 3 through the supply pipe 3a. It is sent into the melting furnace 12 and partially burned at about 1500 ° C. to perform gasification. The molten slag discharged from the furnace 12 is cooled and solidified with water, and then pulverized by a slag crusher 13 to be discharged as granulated slag. On the other hand, the generated combustible gas (gasified gas) is cooled to about 800 ° C. (1073 K) by circulating water in the heat recovery unit 14 and sent downstream.

The waste heat boiler 20 serves to generate steam (steam) by the thermal energy of the combustible gas generated and to reduce the temperature of the gas to about 200 ° C. (473 K) or less. 100 ° C of the steam generated in this way
(373K) to a steam pipe 22
Send to

As means for purifying the combustible gas generated, a dust collector 31, a neutralization tower 32, a washing tower 33, a blower 34, a guard catalyst tower 35, and a carbon dioxide separation tower 40 described later are arranged in this order from the upstream side. are doing. The dust collector 31 is of a bag filter type and mainly removes char (incinerated ash, soot) from combustible gas. The neutralization tower 32 is operated by hydrogen chloride (HCl) or hydrogen sulfide (H
₂ ) Neutralizing acids such as S). The washing tower 3 is for washing gas by spraying water to remove dust, heavy metals, HCl and the like in the gas. The guard catalyst tower 35 is a means for removing HCl, H ₂ S, and the like that have not been removed by the neutralization tower 32 or the washing tower 33 with a catalyst such as calcium (Ca) or lime (CaO, Ca (OH) ₂ ). is there. The chars removed by the dust collector 31 are collected in a collection hopper 36, transported by airflow to the raw material hopper 2, and re-formed together with the waste as a raw material in the gasification furnace 1.
Send in 0.

The gas collecting means 50 includes a blower (pressurizing means) 51 and a gas holder 52. The combustible gas generated by the gas generating means 1 and subjected to dust removal, neutralization, washing and the like by the purifying means 30 is blown by a blower 51 to 5 to 10 kgf.
/ Cm ² (490000 to 980000 Pa), and is stored in the gas holder 52 in a compressed state. In the compressed state, the space required for storage is small, and the supply and use of gas become easy.

The illustrated combustible gas producing apparatus employs the following configuration so that a combustible gas having a high calorific value per unit volume can be efficiently obtained at low cost.

First, as shown in FIG.
0 at the end of carbon dioxide gas separation tower (carbon dioxide gas separation means) 40
And thereby a lot of CO ₂ (70-80%)
Was separated from the flammable gas. The remaining gas from which CO ₂ has been separated is sent from the gas outlet 43 of the separation tower 40 to the gas holder 52 via the blower 51 of the recovery means. By doing so, the proportion of the flammable component in the combustible gas to be recovered in the gas holder 52 is relatively high because CO _2, which is an incombustible component, is reduced, so that a gas having a high calorific value per unit volume can be recovered. Further, by separating CO ₂ , which is a non-combustible component, in the separation tower 40, the amount of gas to be handled is reduced on the downstream side, and the pressurizing power required for the blower 51 is reduced.

For example, 8200 Nm ³ / h of waste gasification gas containing 17% by volume of CO ₂ is supplied from atmospheric pressure to 5 kgf / h.
The theoretical power required when pressurizing to ² cm (490000 Pa) is 880 kW, but according to experiments, part of CO ₂ was separated from the gasified gas to reduce the CO ₂ composition to 4% by volume. When reduced, the power required to pressurize was also reduced by about 20%. In the actual blower 51, the gas at normal pressure (atmospheric pressure) that has exited the carbon dioxide gas separation tower 40 is 5-1 to 1: 1.
0 kgf / cm ² (490000-980,000 Pa)
Since it is normal to pressurize to the extent, considerable power is reduced, and the reduced power will be substantially added to the recovered energy. Also like this
By removing ₂ , there is also an effect that the capacity required for the gas holder 52 is reduced (a small one is sufficient).

Secondly, as the carbon dioxide gas separation column 40, two (or more) containers 41 containing an amine-based solid absorbent (not shown) were arranged in parallel. An amine-based solid absorbent having a functional group such as polyethyleneimine, ethanolamine, diethanolamine, monoethanolamine, or a mixture of diethanolamine and monoethanolamine, adsorbs CO ₂ at a relatively low temperature, and generates vapor, etc. Has the property of desorbing the CO ₂ when heated to regenerate the adsorption performance. for that reason,
Such a solid absorbent is adhered to the surface of a porous solid (not shown) having a diameter of about 1 mm and dried, and a large number of particles (not shown) thus obtained are filled in each container 41. . By flowing a combustible gas between such particulate matter in the container 41, CO ₂ is adsorbed by the absorbent on the surface and most of the gas is separated from the gas.

The two containers 41 are arranged in parallel because CO ₂ is adsorbed on the absorbent in one container while CO ₂ is desorbed from the absorbent in the other container. This is to regenerate the adsorption performance. That is, in the separation tower 40, the flammable gas is alternately switched and introduced into each container 41 via a switching valve (not shown), while the flammable gas is introduced into the container 41 on the side where the flammable gas is not introduced. Low temperature steam is introduced from the waste heat boiler 20 via the steam pipe 2 via another switching valve (not shown). Then, each container 41
Solid sorbent inner repeatedly alternate between adsorption and desorption of CO _2, as the carbon dioxide separation column 40 continuously for long periods of time CO ₂
Can be separated and generated. Since the separation tower 40 is disposed at the end of the purification means 30, that is, at the portion where HCl and H ₂ S in the gas have been sufficiently removed, there is no possibility that the amine-based solid absorbent deteriorates early. . The CO ₂ thus separated is taken out from the CO ₂ take-out port 44 of the separation tower 40 and sent into the carbon dioxide gas holder 45 via the pressurizing means (not shown) and the drying means (gas dryer) 46.

Third, the CO ₂ gas separated from the combustible gas and stored in the carbon dioxide gas holder 45 as described above is
From the path 45a leading to the gasification furnace 10, the gas is blown into the inside of the precombustor 11 as a gasifying agent, that is, a reaction gas. The blown CO ₂ reacts with unreacted C (carbon) at a high temperature inside the pre-combustor 11 and the subsequent partial combustion gasification and ash melting furnace 12, and a large amount of C 2 CO ₂ → 2CO reacts. Turns into CO.

A detailed investigation revealed that when the CO ₂ gas blown with waste in the spouted bed gasifier is 5 to 25% by volume of the total gas supply to the gasifier, the unit of the recovered gas is Lower heating value per volume (LHV)
It was found to be increased 5-15% as compared with the case of not supplying the CO _2. At this time, the lower heating value of the recovered gas as CO ₂ gas is often blown increases, since the costs required to separate the CO ₂ gas from the recovered flammable gas increases at the same time, blown CO ₂ gas 5 25% by volume
It is desirable to be within the range. The cost saved by separating CO ₂ from flammable gas, especially if the CO ₂ gas blown with the waste is 10 to 20% by volume (cost of the entire flammable gas production process)
Is the lowest. Needless to say, the synergistic effect of separating the CO ₂ gas from the gas according to the first configuration can further increase the calorific value per unit volume of the recovered gas. According to the experiment, when 5 to 25% by volume of CO ₂ gas is blown into the waste gasifier and the CO ₂ gas is separated from the generated gas, the calorific value per unit volume of the combustible gas to be recovered is 15 to Increased by 50%.

The fourth point adopted is that the carbon dioxide gas holder 4
That is, the CO ₂ gas stored in 5 is also used as a chore gas in the gasification furnace 10 and the purification means 30 downstream thereof. That is, first, in order to air-flow the waste cut out from the raw material hopper 2 to the gasification furnace 10, a gas path 45b is provided through the lower part of the cut-off valve 2a of each hopper 2 to the pre-combustor 11, and In this case, CO ₂ can be appropriately flowed from the holder 45. In the middle of the route 45b (upstream from the hopper 2)
Is connected to an oxygen supply pipe 3b from the tank 3 so as to promote the pre-combustion of the waste. Also, the dust collector 31
In order to transfer the char removed from the gas and collected in the collection hopper 36 into the raw material hopper 2 by airflow,
c was provided so that CO ₂ could be flown from the holder 45 as needed. Further, the backwash gas (cleaning gas flowing in the direction opposite to the normal flow of the combustible gas) used regularly to prevent the bag filter from being clogged in the dust collector 31 is also provided by the path 45 d continuing from the holder 45. CO ₂ gas is allowed to flow. In addition, in some devices in the gasification furnace 10 and the refining means 30, a cleaning gas is appropriately blown to a viewing window for internal observation, or a gas for sealing is used to prevent air from flowing into necessary openings. Is blown out, and such a gas for cleaning or sealing is also used as the holder 4.
5 is to use the CO ₂ gas stored therein.

Conventionally, nitrogen (N ₂ ) gas has been used as a gas for carrying such airflow, cleaning or sealing. For example, in an apparatus for producing a flammable gas of 5000 Nm ³ / h by gasification of waste, about 200 Nm ³ / h of N ₂ gas has been consumed as a whole. In the illustrated apparatus, such N _2, because then separated in the separation column 40 is cause a substitute for CO ₂ accumulated in the holder 45, the cost of obtaining the N ₂ gas is reduced considerably. In addition, N ₂ is contained in the combustible gas to be recovered.
And the inconvenience of lowering the calorific value is eliminated. As in the case of using N ₂ , it is natural that there is no inconvenience caused by burning the combustible gas by using the miscellaneous gas.

The flammable gas producing apparatus shown in FIG. 1 employs the above-described structure to convert flammable gas having a high calorific value per volume due to a small amount of CO ₂ gas and a high CO content ratio. The production can be carried out in a preferable mode in which the energy consumption and cost expenditure required for the compression of the gas and the acquisition of the miscellaneous gas are suppressed. A part of the steam obtained from the waste heat boiler 20 or the like is blown from a path 45a into CO _2.
If introduced into the gasifier 10 together with the gas,
It is also possible to obtain a combustible gas having a higher content ratio of CO gas and H ₂ gas and a higher calorific value.

In the above description, an example in which combustible gas is generated in the waste gasifier 10 is shown. However, when the gas generating means is a coal gasifier, or further, a steelmaking facility such as a converter is used. In this case, it is possible to efficiently produce a combustible gas having a high calorific value by the same means. In any case, the gas generating means reacts C in the raw material with O ₂ to generate a combustible gas containing CO and CO _2. Therefore, a) separating CO ₂ from the combustible gas. Accordingly, in addition to it is possible to reduce the pressurizing force to increase the heating value of the remaining gas, b) the separated CO ₂ inert by a chore gas N ₂
There is no need to obtain gas or the like, and c) by supplying the CO ₂ to the gas generating means as a gasifying agent, it becomes possible to increase the amount of CO.

[0053]

According to the method for producing a flammable gas according to the first aspect and the apparatus for producing a flammable gas according to the ninth aspect, a desirable flammability having a large amount of CO and a high calorific value per unit volume is obtained. Gas production becomes possible. An additional advantage is that the required capacity of the gas holder for storing flammable gas can be reduced.

In the method for producing a combustible gas according to the second aspect of the present invention, the CO ₂ gas can be reduced without a costly and laborious advanced control even though the raw material waste has large component variations. , The flammable gas having a high calorific value can be recovered.

According to the method for producing a flammable gas according to the third aspect and the apparatus for producing a flammable gas according to the tenth aspect, the CO gas and the H ₂ gas are increased in the flammable gas. The calorific value per unit volume of the combustible gas can be further increased.

According to the method for producing a flammable gas according to the fourth aspect and the apparatus for producing a flammable gas according to the eleventh aspect, N ₂ gas or the like is separately used as a chore gas used for airflow conveyance, sealing, and the like. And there is no inconvenience of lowering the calorific value of the recovered combustible gas.

According to the method for producing a flammable gas described in claim 5, it is possible to obtain a desirable flammable gas having a high calorific value, and at the same time, to reduce the energy and cost required for obtaining a chore gas.

According to the method for producing a flammable gas according to the sixth aspect, furthermore, it is possible to completely remove wastes which are difficult to be put into the furnace due to their light weight and which tend to burn completely in a short time. It is possible to reliably charge the gasification furnace without burning it.

According to the method for producing a combustible gas according to the seventh aspect and the apparatus for producing a combustible gas according to the twelfth aspect, when supplying the combustible gas to a gas turbine for power generation or the like, the gas is pressurized. Power required for the process can be reduced, and much of the recovered gas energy can be used effectively.

According to the method for producing a combustible gas according to the eighth aspect and the apparatus for producing a combustible gas according to the thirteenth aspect, a combustible gas having a high calorific value can be recovered, and energy and cost required for obtaining a chore gas can be obtained. Therefore, there is an extremely favorable effect on energy recovery that it is possible to reduce the power required for pressurizing gas required for a gas turbine for power generation and the like.

[0061] According to the apparatus for producing combustible gases according to claim 14, after separating the CO ₂ from the combustible gas CO ₂
The operation of sending the gas and the remaining gas to different paths can be continuously performed for a long period of time.

[Brief description of the drawings]

FIG. 1 shows an overall system diagram relating to an apparatus for producing combustible gas by gasification of waste, as an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Gas generation means 10 Gasification furnace 20 Boiler 22 Steam pipe 30 Purification means 40 Carbon dioxide gas separation tower (carbon dioxide gas separation means) 41 ・ 42 Container 45 Carbon dioxide gas holder 46 Drying means 45a ・ 45b ・ 45c ・ 45d (carbon dioxide gas ) Path 51 Blower (pressurizing means) 52 Gas holder

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) B01J 20/34 B01J 20/34 F C10J 3/02 C10J 3/02 JHCF 3/46 3/46 JH C 3/48 3/48 C10K 3/00 C10K 3/00 F01K 27/02 F01K 27/02 C F02C 3/28 F02C 3/28 (72) Inventor Eiichi Harada 1st Kawasaki-cho, Akashi-shi, Hyogo Prefecture No. 1 Kawasaki Heavy Industries, Ltd.Akashi factory (72) Inventor Hironori Ozaki 1-3-1, Higashikawasaki-cho, Chuo-ku, Kobe-shi, Hyogo Kawasaki Heavy Industries, Ltd. 1-3-3 Higashi Kawasakicho Kawasaki Heavy Industries, Ltd. Kobe Head Office F-term (reference) 3G081 BA11 BC13 DA22 4D020 AA03 BA16 BA19 BB01 BB03 BB07 BC01 CA05 CD02 CD03 4G066 AB13B AD11B AE19C CA 35 DA04 EA20 GA01 GA06 4H060 AA01 AA02 BB02 BB03 BB33 CC14 DD02 EE01 EE03 GG01

Claims (14)

[Claims] A flammable gas containing carbon monoxide is generated in a gas generating means, a carbon dioxide gas is separated from the generated flammable gas, and the separated carbon dioxide gas is used as a gasifying agent in the gas generating means. A method for producing a combustible gas, comprising supplying the gas. 2. The method for producing a combustible gas according to claim 1, wherein a waste gasifier for gasifying waste to generate said combustible gas is used as said gas generating means. . 3. The method according to claim 1, wherein steam is obtained by the retained heat of the generated combustible gas, and the steam is supplied to the gas generating means together with the separated carbon dioxide gas as a gasifying agent. The method for producing a flammable gas described in 1 above. 4. A flammable gas containing carbon monoxide is generated in gas generating means, carbon dioxide is separated from the generated flammable gas, and the separated carbon dioxide is passed through the gas generating means or the gas. A method for producing a combustible gas, which is used as a chore gas in a route. 5. The method for producing a combustible gas according to claim 4, wherein the separated carbon dioxide gas is simultaneously supplied as a gasifying agent to the gas generating means. 6. A waste gasifier which gasifies waste to generate the above combustible gas is used as the gas generating means, and the separated carbon dioxide gas is charged into the gasifier. The method for producing a combustible gas according to claim 4, wherein the method is used as a gas for carrying an airflow for the purpose. 7. A gas turbine for generating electricity by generating a combustible gas containing carbon monoxide in gas generating means, separating carbon dioxide gas from the generated combustible gas, and pressurizing the remaining combustible gas. A method for producing a flammable gas, which is supplied to a gas engine. 8. The method according to claim 1, wherein the separated carbon dioxide gas is supplied as a gasifying agent to the gas generating means, and is used as a chopping gas in the gas generating means or a passage of the gas. Item 8. A method for producing a combustible gas according to Item 7. 9. A carbon dioxide gas separating means is disposed in a gas path following the gas generating means for generating a carbon monoxide-containing combustible gas, and the carbon dioxide gas outlet of the separating means is provided with a pressurizing means. A flammable gas producing apparatus connected to the reaction chamber of the gas generating means via 10. A boiler is disposed in a gas path following the combustible gas generating means, and a steam pipe is connected from the boiler to a reaction chamber in the gas generating means. Item 10. An apparatus for producing combustible gas according to item 9. 11. A carbon dioxide gas separating means is disposed in a gas path following a gas generating means for generating a flammable gas containing carbon monoxide, and the carbon dioxide gas outlet of the separating means is provided with a pressurizing means. And an apparatus for producing combustible gas, wherein the apparatus is connected to a gas holder which can be taken out at any time via drying means. 12. A carbon dioxide gas separating means is disposed in a gas path following a gas generating means for generating a flammable gas containing carbon monoxide, and an outlet of the remaining separated gas in the separating means is provided. An apparatus for producing a combustible gas, wherein the apparatus is connected to a gas turbine or a gas engine for power generation via a pressurizing means. 13. An outlet for carbon dioxide gas in the separation means, which is connected to a gas holder which can be taken out at any time via a pressurizing means, and the gas holder is a reaction chamber in the gas generating means. 13. The apparatus for producing a combustible gas according to claim 12, wherein the apparatus is connected to a fuel cell. 14. A plurality of containers containing an amine-based solid absorbent or a liquid absorbent as the separating means are arranged in parallel, and a boiler is arranged in a gas path following the gas generating means. The apparatus for producing a combustible gas according to any one of claims 9 to 13, wherein a steam pipe is connected from the boiler to the container.