JP5130459B2 - Operation method of coal pyrolysis gasifier - Google Patents

Description

  The present invention relates to a method for operating a coal pyrolysis gasifier for converting coal into gas or oil with high efficiency and making effective use.

  Coal is an abundant reserve and a low-priced energy resource that is still gaining importance today. However, the disadvantage of coal is that it is a solid (because it is solid, it has poor handling properties, impurities such as sulfur, etc. The development of clean coal technology or coal conversion technology as a means to solve many) is also accelerating.

  In particular, coal gasification technology that converts coal into synthesis gas is applicable to coal gasification combined power generation (IGCC), which can improve power generation efficiency over conventional pulverized coal-fired boiler power generation. , Attracting attention. There are several types of coal gasification technology, such as fixed bed type, fluidized bed type, and airflow bed (spouted bed) type. However, in recent years, it is easy to increase the size, and the ash content in coal is slagged. Attention has been focused on the air-bed type coal gasifier that can be used.

  There are several types of gas bed type coal gasifiers, but names such as Shell, Prenflo, Hycol (Eagle), etc. have been adopted as methods of using air flow when coal is introduced into the gasifier. A gasifier of the type referred to above has been proposed so far.

  For example, Patent Document 1 proposes a gasification furnace in which coal is blown in a swirling flow from a burner arranged in two stages in a gasification furnace in one chamber.

  Patent Document 2 proposes a coal gasification apparatus including a combustor section and a reductor section.

  In Patent Document 3, char generated by pyrolysis of coal is gasified in the gasification unit, and coal is blown into the high-temperature gas generated in the gasification unit in the pyrolysis unit installed in the upper stage of the gasification unit. Thus, a pyrolysis gasification method for coal producing gas, tar, and char has been proposed.

  Patent Document 4 proposes a method and an apparatus for gasifying coal using a gas bed type apparatus composed of a gasification furnace and a pyrolysis furnace under a high pressure condition of 10 atm (1 MPa) or more.

JP 60-173092 A JP-A 61-207493 JP-A-5-295371 JP-A-11-302666 JP 2002-80863 A 1994 Survey Report (NEDO-C-9429) "Coal Utilization Next-Generation Technology Development Survey Coal Pyrolysis Technology Field" New Energy and Industrial Technology Development Organization, 1995, p. 4

  Generally, when starting up a coal gasification furnace (starting up the furnace), the coal gasification (partial oxidation, partial combustion) reaction is caused stably (continuously), and the gasification furnace, and In order to avoid problems such as condensation (condensation of water) or tar condensation, slag adhesion, etc. in the incidental equipment at the subsequent stage, preheating (temperature increase) operation in the furnace and incidental equipment is performed in advance. To do is essential.

  In order to perform preheating, a dedicated burner (preheating burner, temperature rising burner) that uses a gas or liquid fuel other than coal, which can be easily ignited and burned, as the heat source is used before the start of coal injection (gasification). Before starting), it is necessary to raise the temperature in the furnace to a predetermined temperature. As the fuel used in the preheating burner, gas fuel such as natural gas (LNG) and liquefied petroleum gas (LPG), and liquid fuel such as light oil, kerosene, and heavy oil are often used.

  Coal gasifiers have the advantage of being able to make the internal volume of gasifiers compact and the need for high pressure on the latter side (gas turbine power generation, synthesis of chemicals such as methanol) that uses the gasified gas that is the product. Therefore, it is common to operate under a certain pressure state (most coal gasification furnaces are often operated at a pressure of 1 MPa or more, usually about 2 to 3 MPa).

  Therefore, when the coal gasification furnace is started up, not only the preheating operation but also the pressure raising operation in the furnace must be performed in advance.

  Patent Document 5 proposes a method for operating a coal gasifier that simultaneously performs preheating and pressure increase in the gasifier in order to shorten the time required to start up these coal gasifiers.

  However, in the method proposed in Patent Document 5, since preheating and pressurization are performed simultaneously, it is necessary to use a preheating burner having a special structure capable of stably burning fuel under a wide range of pressure conditions. is there. This preheating burner has a complicated structure for high pressure, but is also expensive, and at the same time, a complicated control device for performing precise operation control of the combustion state according to the change in pressure is also required. There was a problem.

  In addition, all equipment associated with the preheating burner (fuel boosting compressor, combustion air compressor, each pipe, valve, etc.) needs to have a so-called high pressure specification that can be operated under pressure boosting. There was a big problem that the cost related to the necessary equipment would be even higher.

  In Non-Patent Document 1, another method for starting up a coal pyrolysis gasifier is proposed. That is, first, in a state where the gasification furnace is at normal pressure (atmospheric pressure), the preheating operation by the preheating burner is started, the temperature is raised to a predetermined temperature, and the preheating is completed (the preheating burner is extinguished). . Next, the gasification (and thermal decomposition) of coal is started, and at the same time, the pressure increase operation in the furnace is performed.

  According to this method, since the preheating burner itself is used only when the inside of the furnace is at normal pressure (atmospheric pressure), the preheating burner itself and the equipment attached to the preheating burner are used at normal normal pressure. Since the specification is sufficient, it is possible to greatly simplify and reduce the cost as compared with the method described above.

  However, in the method according to Non-Patent Document 1, it is necessary to continue the gasification (or thermal decomposition) of coal in parallel with the pressure increase. At this time, as the pressure in the furnace increases, the gas flow velocity (linear velocity) in each part of the furnace gradually decreases.

  Naturally, when installing the gasification furnace, it is designed to have an appropriate furnace flow rate under normal pressure conditions after boosting, which is a steady state during operation. In the (atmospheric pressure) state, the gas flow rate is extremely large, several times to several tens of times that in the steady state. Such a gas flow rate faster than the steady state may cause various problems for the gasifier and is not preferable.

  Specifically, the flame (flame) in the gasification burner in the gasification furnace becomes longer, causing trouble that damages the furnace wall facing the burner or slag generated in the gasification furnace, It is a slag adhesion (slagging) trouble etc. which generate | occur | produces in the vicinity of a gasifier exit or the back | latter stage part of a gasifier by being entrained by.

  At the beginning of pressurization, the flow rate of the gasification gas generated by controlling the flow rate of the gasification gas generated by decreasing the supply amount of coal to be gasified and gradually increasing the supply amount of coal with pressure increase, Although it is conceivable to adjust within the range, in a general coal supply feeder, there is a limit to the range in which the supply amount can be turned down (for example, in 2 MPa operation, 1 / It is virtually impossible to always manage the inside of the furnace at a constant flow rate under all pressure conditions during pressurization.

  In view of the above problems, an object of the present invention is to provide a method for operating a coal pyrolysis gasifier capable of stably and reliably starting up a coal pyrolysis gasifier while reducing initial equipment costs. Is to provide.

  As a result of intensive studies in view of the above problems, the present inventors have found that the above problems can be solved by sequentially performing preheating, pressurization, and gasification in three stages.

  At that time, since the gas temperature in the furnace decreases in the pressure-up stage, there was a concern about whether or not to stably ignite at the start of gasification. Because it is composed of slag adhering in this test, the heat storage performance is high, the temperature of the furnace wall itself does not drop rapidly, and even if gasification is performed after the pressurization is completed, the coal put into the gasification chamber It was found that oxygen and oxygen were instantaneously heated by the sensible heat of the furnace wall and ignited, and the present invention was completed.

  The configuration of the present invention for achieving the above object is as follows.

  (1) having a two-chamber two-stage structure comprising a lower gasification chamber having a preheating portion at the lower portion and an upper pyrolysis reforming chamber connected to the gasification chamber via a throat portion; Using a coal pyrolysis gasification furnace with an operating pressure of 1 MPa (gauge pressure) or more and blowing one or two of coal and char together with oxygen into the gasification chamber to cause a partial oxidation reaction. Gasification gas mainly containing hydrogen, carbon monoxide, water vapor, and carbon dioxide is generated, and coal is blown into the pyrolysis reforming chamber in the subsequent stage to flow into the gasification furnace. A method for operating a coal pyrolysis gasification furnace that thermally decomposes coal in the pyrolysis reforming chamber using gas sensible heat to generate gas, oil, and char, the coal pyrolysis gasification When starting up the furnace, After preheating the inside of the coal pyrolysis gasification furnace using a normal pressure preheating burner installed in the preheating section and stopping the preheating burner upon completion of the preheating, the coal pyrolysis gasification is then performed. Pressurizing the furnace, and after completion of the pressurization, coal pyrolysis is performed by blowing one or two of coal and char together with oxygen into the gasification section and blowing coal into the pyrolysis reforming chamber. How to operate the gasifier.

  (2) The preheating unit is partitioned through a slag tap installed in the gasification chamber, and a slag tap burner for heating and keeping the slag tap is installed in the preheating unit. The method for operating a coal pyrolysis gasifier as described in (1) above.

  (3) When the coal pyrolysis gasification furnace is started up, the slag tap burner is burned, and after the exhaust gas generated by the combustion is brought into a state in which unreacted oxygen is contained, the gasification is performed. The method for operating a coal pyrolysis gasifier according to (2) above, wherein one or two of coal and char are blown into the part together with oxygen.

  (4) The means for bringing unreacted oxygen into the combustion exhaust gas of the slag tap burner is to make the amount of oxygen supplied to the slag tap burner equal to or greater than the theoretical combustion oxygen amount. The method for operating a coal pyrolysis gasifier as described in (3) above.

  The present invention enables stable and reliable start-up and operation of a coal pyrolysis gasification furnace while reducing initial equipment costs.

  Hereinafter, the present invention will be described in detail. FIG. 1 shows a process flow relating to the present invention.

  The coal pyrolysis gasification furnace 1 of the present invention is composed of two chambers having different internal reactions, and has a two-stage blow type structure in which carbonaceous raw materials such as coal and / or char are introduced into each chamber. And That is, the lower stage is a gasification chamber 2 for gasifying coal or the like by a partial oxidation reaction using oxygen as a gasifying agent, and the upper stage is coal in high-temperature gasification gas generated in the gasification chamber 2. A pyrolysis reforming chamber 3 is installed in which a pyrolysis reaction is caused by blowing.

  Further, by dividing the gasification chamber 2 and the pyrolysis reforming chamber 3 by a throat portion 4 (throttle portion) narrower than the respective furnace diameters, both conditions such as reaction and temperature occurring inside are respectively determined. To be easy to manage separately.

  The coal blown into the pyrolysis reforming chamber 3 or the char generated in the pyrolysis reforming chamber 3 remains in the pyrolysis reforming chamber 3 for a certain period of time. By appropriately managing the gas flow rate in 4, it is possible to prevent the gas from falling to the gasification section.

  The gasification chamber 2 is divided into an upper gasification section 2a and a lower preheating section 5 via a slag tap. The preheating unit 5 is connected to the gasification unit 2a via a discharge port (slag tap 6) provided at the bottom of the gasification unit 2a in order to extract the slag generated in the gasification unit 2a from the gasification unit. The slag extracted from the slag tap 6 is stored in a granulated part (slag pot 7) further below the preheating part.

  A slag tap burner 9 is installed in the preheating section 5 and the slag tap 6 is kept warm as needed to avoid slag clogging troubles in the slag tap 6. As the fuel 10-1 used in the slag tap burner 9, any gas or liquid fuel can be used. In order to efficiently keep the slag tap 6 at a high temperature with a small amount of fuel supply, oxidation for combustion is used. As the agent, it is desirable to use oxygen 11-1 instead of air.

  In addition, since the slag tap burner 9 aims at local heat insulation, it should just install the burner of a small combustion capacity (1/3 or less) compared with the preheating burner 12 mentioned later. Although a case in which the slag tap burner 9 is not installed can be selected, it is desirable to install the slag tap burner 9 in order to completely eliminate the possibility of a clogging trouble occurring in the slag tap 6.

  In the preheating unit 5, a preheating burner 12 for performing preheating at the time of starting up the equipment is installed. Although it is not impossible to install the preheating burner 12 in the gasification unit 2a, since the preheating burner is stopped when coal gasification is performed, the slag generated during the gasification is caused by a burner nozzle or The preheating burner 12 is desirably installed in the preheating unit 5 because it takes time and effort to clean and remove them when the equipment is started up every time it is attached.

  In starting up the facility, the preheating burner 12 is ignited in the normal pressure (atmospheric pressure) state in which the inside of the coal pyrolysis gasification furnace 1 is not pressurized, and the furnace body and the auxiliary equipment in the subsequent stage are preheated.

  In the present invention, the normal pressure state as the pressure condition for using (combusting) the preheating burner 12 indicates atmospheric pressure (101325 Pa = absolute pressure), but the preheating burner 12 is placed in the furnace. The pressure increase caused by combustion and the combustion exhaust gas staying in the furnace is also included in the range of the normal pressure state.

  As the fuel 10-2 of the preheating burner 12, natural gas (LNG), city gas, liquefied petroleum gas (LPG), coke oven gas (COG), converter gas (LDG), which is a gas (gas) fuel, You may use anything, such as blast furnace gas (BFG) etc., or light oil, kerosene, heavy oil which is a liquid fuel.

  Since this preheating burner is used only in the normal pressure state, a compressor (compressor) for boosting the gas fuel is not necessary, and it can be covered by the gas pressure supplied by piping for each factory.

  Of course, the gas supply pressure varies from factory to factory, so it cannot be defined unconditionally, but general factory pressure (pressure less than 1.0 MPa (gauge pressure) not subject to the High Pressure Gas Safety Law) is sufficient. is there.

  The fact that a compressor is not required means that the type of gas that cannot be boosted due to troubles caused by condensation, adhesion, etc. of tar in a normal compressor, such as coke oven gas containing a large amount of tar, This means that it can be used as the preheating burner fuel 10-2, which is also an advantageous point.

  In addition, when using liquid fuel, it is necessary to install a tank for storing the fuel anyway, but the pump for boosting the liquid fuel has a pressure of about 0.01 to 0.5 MPa. Since it is sufficient to use a low-pressure specification, it is advantageous from the viewpoint of equipment cost and reduction of operating power.

  The combustion air 13 supplied to the preheating burner 12 together with the fuel 10-2 may be supplied directly from the factory piping. Moreover, what is necessary is just to use the thing of the low pressure specification of about 0.01-0.5 Mpa also about the case where a dedicated blower is installed without supplying the combustion air 13 from factory piping.

  Since the combustion air 13 is overwhelmingly larger in the flow rate supplied to the preheating burner 12 than the fuel 10-2, it is possible to suppress the combustion air 13 by increasing the pressure to a relatively low pressure. From the viewpoint of power reduction, it is extremely suitable.

  As described above, the pipe for supplying the fuel 10-2 and the combustion air 13 is used only in the normal pressure state where the pressure inside the coal pyrolysis gasification furnace 1 is not increased, and the compressor is installed as necessary. A preheating burner 12 of a type in which a blower, a pump and the like are set to a low pressure specification equal to or lower than the operating pressure of the coal pyrolysis gasification furnace 1 is defined as a normal pressure specification preheating burner 12.

  Conversely, in order to use the inside of the coal pyrolysis gasification furnace 1 within the range from the normal pressure to the operating pressure (after pressure increase), high-pressure piping for supplying the fuel 10-2 and the combustion air 13, and A preheating burner 12 of a type that requires the installation of a high-pressure compressor, blower, and pumps for boosting them to a pressure higher than the operating pressure of the coal pyrolysis gasifier 1 is used. It is defined as 12.

  Thereafter, by continuing the combustion of the preheating burner 12, the temperature in the gasification section 2a and in the incidental equipment in the subsequent stage is raised to the initially set target temperature. The target temperature at this time varies depending on the material constituting the furnace body or equipment, the type of coal used, etc., but the temperature in the gasification section 2a is such that carbon in the coal is ignited and gasification reaction with oxygen occurs. The temperature of 600 ° C. or higher at which the gasification proceeds reliably, and the temperature in the incidental equipment (including the pyrolysis reforming chamber) downstream of the gasification unit 2a is 400 ° C. or higher that can suppress the condensation and adhesion of the generated tar. It is desirable.

  After reaching the target temperature in the furnace and the incidental equipment, first, the slag tap burner 9 is ignited, and then the preheating burner 12 is extinguished. The slag tap burner 9 may be ignited after the preheating burner 12 is extinguished. However, since the slag tap burner 9 usually does not always have an ignition plug, the slag tap burner 9 can be surely moved to a reliable slag tap burner 9. In order to perform this ignition, it is desirable to ignite the slag tap burner 9 before the preheating burner 12 is extinguished.

  At the same time as the preheating burner 12 is extinguished, pressure increase is started. The pressurization is performed by the combustion exhaust gas of the slag tap burner 9 and the nitrogen 14 for pressurization supplied separately. At this time, the inside of the facility including the coal pyrolysis gasification furnace 1 that has been heated by preheating is cooled again by the introduction and heat dissipation of the pressure-increasing nitrogen 14, so that it is within an allowable range in terms of the specifications of the facility. It is desirable to boost the voltage in as short a time as possible.

  Although it is possible to boost the equipment using only the flue gas of the slag tap burner 9 without introducing the boosting nitrogen 14, the time required for boosting becomes longer. 14 is preferably used for boosting.

  The introduction position of the pressurization nitrogen 14 is not particularly defined, but in order to minimize the temperature drop in the gasification section 2a during the pressurization, the combustion exhaust gas of the slag tap burner 9 is contained in the gasification section 2a. It is desirable to preferentially stay (minimize the effect of cold pressurizing nitrogen 14).

  Accordingly, the boosting nitrogen 14 is not introduced into the preheating unit 5 or the gasification unit 2a, but is introduced from the vicinity of the pyrolysis reforming chamber 3 or the coal pyrolysis gasification furnace 1 outlet, or any place after that. It is preferable to do.

  Moreover, the pressure adjustment in the coal pyrolysis gasification furnace 1 is performed by adjusting the opening degree of the pressure adjustment valve 15 installed in the rear stage of the coal pyrolysis gasification furnace 1.

  In addition, when using the slag tap burner 9, unlike the preheating burner 12, it is necessary to set it as a high voltage | pressure specification. However, as described above, since the combustion capacity of the slag tap burner 9 is significantly smaller than that of the preheating burner 12, a small-scale compressor or the like for boosting the fuel 10-1 may be installed.

  Furthermore, regarding the oxygen 11-1 used as the oxidant for combustion, the oxygen 11-2 used as the gasification gasifying agent (oxidant) may be partially branched and used as a slag. Since it is not necessary to install an oxidizer charging facility for the tap burner 9, the cost of the burner and incidental facilities can be significantly reduced compared to a case where the preheating burner 12 is of a high pressure specification.

After raising the inside of the coal pyrolysis gasification furnace 1 to a normal pressure during operation (1.0 MPa or more, gauge pressure), the gasification unit 2a starts coal gasification. That is, coal 16-1 is gasified together with oxygen 11-2 as a gasifying agent, and gasified burner 17 is blown into gasification section 2a to cause partial oxidation (partial combustion) reaction, thereby gasifying coal 16-1. Gas 18 (main components are hydrogen (H ₂ ), carbon monoxide (CO), water vapor (H ₂ O), carbon dioxide (CO ₂ ), methane (CH ₄ )).

  As described above, during the pressurization, the average temperature of the gas staying in the gasification section 2a is rapidly decreased, but the temperature of the furnace wall (refractory material) itself of the gasification section 2a that is sufficiently stored and difficult to cool is Since it does not decrease so rapidly, when the gasification part 2a is preheated to 1000 ° C., the gasification part 2a is put into the gasification part 2a within about 4 hours after the preheating burner 12 is stopped. Coal 16-1 and oxygen 11-2 are instantaneously heated and ignited by the sensible heat of the furnace wall, and coal gasification reaction (partial oxidation reaction) starts.

  However, since the preheat burner 12 is stopped and gasification in the gasification section 2a is started, a time longer than 4 hours as a guide has elapsed, and the furnace wall temperature itself causes the coal to ignite. Even if the temperature is below the required temperature, or even if the time from the stop of the preheating burner 12 to the start of gasification is within 4 hours, the pressure-increasing nitrogen 14 blown into the furnace during pressure increase There may be a case where coal blown into the gasification section does not ignite (gasification reaction does not occur), such as when the furnace wall surface is easily cooled due to the relationship between the blow amount and the blow position.

  Assuming such a case, the following method is adopted as means for reliably igniting the coal 16-1 in all cases. That is, by mixing unreacted oxygen into the flue gas from the slag tap burner 9, oxygen in the same temperature state as the flue gas (heated state, not normal temperature) is present, and this heating causes the reaction. This is a method of reliably igniting coal by bringing the enhanced oxygen into contact with coal 16-1.

  As a method of mixing unreacted oxygen into the combustion exhaust gas from the slag tap burner 9, the amount of oxygen 11-1 supplied to the slag tap burner 9 is similarly changed to the fuel 10- supplied to the slag tap burner 9. By setting the amount to be equal to or greater than the theoretical combustion oxygen amount for 1, it is preferable that unreacted (surplus) oxygen exists in the combustion exhaust gas.

  Of course, the oxygen supply amount to the slag tap burner 9 is kept at the theoretical combustion oxygen amount with respect to the fuel, and oxygen is supplied from a nozzle or the like separately installed in addition to the slag tap burner 9, so that it has not reacted in the combustion exhaust gas. Although it may be adjusted so that oxygen is present, the provision of a dedicated oxygen supply nozzle causes an increase in equipment costs, and the exhaust gas and oxygen separately supplied do not mix well and are added with great effort. Since it is assumed that the temperature of the oxygen does not rise sufficiently, it is desirable that the oxygen supply amount in the slag tap burner 9 is equal to or greater than the theoretical combustion oxygen amount.

  At this time, the oxygen supply amount in the slag tap burner 9 is desirably an oxygen ratio of 1.1 or more (the oxygen ratio in the case of the theoretical combustion oxygen amount is defined as 1.0). An oxygen ratio lower than 1.1 is undesirable because the oxygen partial pressure in the flue gas is too low and the coal may not ignite immediately.

  Also, the combustion conditions (fuel type, oxygen ratio, etc.) in the slag tap burner 9 should be adjusted so that the theoretical combustion temperature (adiabatic flame temperature) of the combustion exhaust gas (the state where unreacted oxygen is present) is 1000 ° C. or higher. Is desirable. When the theoretical combustion temperature is lower than 1000 ° C., the combustion exhaust gas temperature when it is introduced into the gasification section 2a and comes into contact with coal may be lowered to 600 ° C. or less, which is the ignition point of carbon, due to heat dissipation. The theoretical combustion temperature of the combustion exhaust gas is preferably 1000 ° C. or higher.

  The gasification gas 18 generated in the gasification chamber 2 which is the lower stage of the two-stage two-stage coal gasification pyrolysis furnace 1 is connected to the gasification section 2a via the throat section 4 in the upper stage. Immediately introduced into the reforming chamber 3. The gasification gas 18 contains about 10 to 35% by volume of hydrogen from the beginning, but in order to promote the hydrocracking reaction of coal in the pyrolysis reforming chamber 3, separately, The hydrogen concentration may be further increased by adding the hydrogen-containing gas 19 into the pyrolysis reforming chamber 3.

  Regarding the temperature (reaction temperature) of the gasification section 2a, if it is lower than 1200 ° C., the coal is not sufficiently gasified and the slag is continuously and stably extracted from the slag tap 6 at the bottom of the gasification section 2a. On the other hand, if the temperature exceeds 1700 ° C, the life of the furnace wall of the gasification section 2a is extremely shortened, and heat loss due to heat dissipation increases, so that the temperature is preferably set to 1200 ° C to 1700 ° C.

  The pressure of the gasification part 2a is preferably 1.0 MPa (gauge pressure) or more in order to accelerate the gasification reaction rate and make the gasification part 2a compact. The upper limit of pressure is not specified, but to prevent an increase in equipment costs due to excessively high pressure, and the final process product (gas, oil) is used as fuel for power generation (gas turbine fuel) or chemical raw material When used, since the pressure required on the product side is generally about 2 to 3 MPa (gauge pressure), it is preferably 5.0 MPa (gauge pressure) or less.

  At this time, water vapor 20-1 may be used in combination with oxygen 11-2 as a gasifying agent for the purpose of temperature control (preventing excessive temperature rise) in the gasification section 2a.

  The gasification gas 18 generated in the gasification chamber 2, which is the lower stage of the two-chamber two-stage coal gasification pyrolysis furnace 1, is connected to the gasification chamber 2 through the throat portion 4 in the upper stage. Immediately introduced into the reforming chamber 3.

  In the pyrolysis reforming chamber 3, the finely powdered coal 16-2 blown from the coal nozzle 21 is mixed with the previous high-temperature gasification gas 18, whereby the sensible heat of the gasification gas 18 is converted into a heat source. As rapid heating and pyrolysis.

First, in the primary pyrolysis reaction that occurs at the beginning of the reaction, coal consists of pyrolysis gas (main components are H ₂ , CO, CO ₂ , H ₂ O, hydrocarbon gas), and 3 heavy benzene rings. The above polycyclic aromatics are decomposed into tar and solid char which occupy most of the components.

These pyrolysis reaction products are subsequently subjected to a pyrolysis secondary reaction, and the hydrocarbon gas in the pyrolysis gas is further converted into hydrocarbon gases of lower molecular weight (CH ₄ , C ₂ H ₆ , C ₃ H ₈ , C ₂ H ₄ , C ₃ H _6, etc.) and tar is a gas (main components are H ₂ , CO, CO ₂ , H ₂ O, hydrocarbon gas) or a benzene ring such as BTX or naphthalene. The light component of about 3 rings is decomposed into oil which occupies the main component.

  All tars are pyrolyzed into gas under conditions where the pyrolysis reforming chamber 3 is at a high temperature. The high temperature conditions in this case vary depending on the type of coal, but if the temperature is 1000 ° C. or higher, generally all tar is decomposed into gas.

In addition, a part of the char is also converted into a hydrocarbon gas mainly containing CH ₄ by the hydrogenation reaction shown in the formula (1), or CO or It is converted to H _2.

C (Char) + H ₂ → Low molecular hydrocarbon gas (CH ₄ etc.) (1)
C (Char) + CO ₂ → 2CO (2)
C (Char) + H ₂ O → CO + H ₂ (3)

  Among the reactions related to these chars, the gasification reaction with water vapor of the formula (3) has a reaction rate several times faster than the other two reactions under certain reaction conditions (temperature, pressure). This is the most effective reaction for reducing the amount of char generated in the pyrolysis reforming chamber 3.

Further, as in the present invention, char produced by rapid heating (100 ° C./sec or more) of coal is produced by these gases (H ₂ , CO ₂ ) even in a relatively low temperature range (700 to 1100 ° C.). Since it is an active char that is extremely excellent in reactivity with water vapor), it is suitable for causing a water vapor gasification reaction.

  In the pyrolysis reforming chamber 3, water vapor for reacting with char is supplied as a component in the gasification gas 18 introduced from the gasification section 2a. Moreover, the reaction rate regarding the steam gasification reaction of char increases as the pressure, temperature, and water vapor concentration increase.

  Therefore, in order to promote the gasification reaction within a reaction time as short as possible under a certain pressure and temperature condition, and further reduce the amount of char formation, a separate steam directly into the pyrolysis reforming chamber. 20-2 may be added to increase the steam partial pressure in the pyrolysis reforming chamber 3.

  The gasification gas 18 contains about 10 to 35% by volume of hydrogen from the beginning. However, in order to promote the hydrocracking reaction of coal in the pyrolysis reforming chamber 3, it is separately provided. The hydrogen concentration may be further increased by adding the hydrogen-containing gas 19 into the pyrolysis reforming chamber 3.

  The residence time of the gas in the pyrolysis reforming chamber 3 is desirably set to such an extent (0.5 to 10 sec) that the gas or tar is sufficiently thermally decomposed and secondarily reacted and the furnace size is not increased more than necessary. .

  On the other hand, in general, char generated by pyrolysis stays in the furnace for a longer time than gas. In particular, in the present invention, in order to sufficiently advance the reaction between char and water vapor, It is important to control the upward gas flow rate in the pyrolysis reforming chamber 3 so that the residence time is as long as possible, that is, the char stays in the pyrolysis reforming chamber 3 to some extent. The appropriate flow rate at that time varies depending on the char properties (specific gravity, particle size, etc.), but is preferably about 0.1 to 10 m / sec.

  When the gas flow rate is smaller than 0.1 m / sec, the char is hardly accompanied by an upward flow of gas and falls toward the gasification section. On the other hand, if it is greater than 10 m / sec, the char is hardly accumulated in the pyrolysis reforming chamber 3 and is released from the furnace within the same residence time as the gas. From the viewpoint of promoting the gasification reaction, the gas flow rate in the pyrolysis reforming chamber 3 is desirably about 0.1 to 1 m / sec.

  In addition, in order to prevent an increase in equipment cost associated with an increase in the size (furnace length) of the pyrolysis reforming chamber 3, the gas residence time is set to 3 sec or less in which the pyrolysis secondary reaction is almost completed, and the gas flow rate It is preferable to determine the furnace length of the pyrolysis reforming chamber 3 within a range of 1 m / sec or more where most of the char is entrained with airflow and 5 m / sec or less where char stagnation occurs moderately.

  The reaction conditions in the pyrolysis reforming chamber 3 are preferably a temperature of 500 to 1200 ° C. and a hydrogen concentration of 10 to 70%. In particular, in order to increase the yield of light oil components such as BTX and naphthalene, It is desirable that the temperature is 600 to 900 ° C. and the hydrogen concentration is 10 to 50%.

  The hydrogen concentration defined here is the hydrogen concentration in the atmosphere before the coal is pyrolyzed in the pyrolysis reforming chamber 3, that is, gasified gas, hydrogen added from the outside or hydrogen-rich gas, etc. This means the hydrogen concentration (estimated value) in the gas in which the working gas, purge gas, etc. are mixed.

  Further, the coal 16-2, the hydrogen-containing gas 19, and the water vapor 20-2 may all be blown from the same coal nozzle 21 or from separate nozzles.

  The pressure in the pyrolysis reforming chamber 3 is desirably 1.0 MPa or more and 5.0 MPa or less (both are gauge pressures) for the same reason as in the gasification section 2a.

  Most of the molten slag generated in the gasification section 2a is extracted from the slag discharge port (slag tap 6) at the furnace bottom and recovered as slag 8. Even if the equipment is operated in the steady state after the pressure increase, a part of the slag generated in the gasification unit 2a is accompanied by the gasification gas 18 and enters the pyrolysis reforming chamber 3. And introduced. However, under the condition where char is present in the pyrolysis reforming chamber 3, since the accompanying slag is prevented from adhering to the furnace wall, troubles such as clogging due to slagging no longer occur.

  Thus, the process product 22 mainly composed of the gas discharged from the coal pyrolysis gasifier 1 is processed in the gas processing facility 23 according to the intended use of the process product.

  The equipment that constitutes the gas treatment equipment 23 includes waste heat recovery equipment (waste heat boiler, heat exchanger, etc.), dedusting (char separation) equipment (cyclone, metal filter, ceramics filter, bag filter, venturi scrubber, electricity Dust collector), desulfurization equipment, gas cleaning equipment (Venturi scrubber, gas absorption tower), ammonia removal equipment, oil recovery equipment, tar removal equipment, etc. are applicable, and appropriate equipment shall be selected as necessary.

  In addition, a gas quencher 24 may be installed between the coal pyrolysis gasification furnace 1 and the gas processing facility 23 in order to reduce the heat load in the gas processing facility 23.

  The char 25 collected in the gas processing facility 23 may be introduced into the gasification unit 2a after passing through the char recycling facility 26 and converted into the gasification gas 18 together with the coal 16-1. At this time, the char may be blown into the gasification unit 2a from the same gasification burner 17 after being mixed with the coal 16-1, or may be blown into the gasification unit 2a from a burner separate from the coal.

  Of course, the char 25 may not be recycled to the gasification unit 2a, but may be used for fuel in other facilities (boilers or the like), or for other uses such as a blast furnace reducing agent and activated carbon raw material.

  The final process product 27 (flammable gas and oil) is used for various applications such as power generation fuel, chemical raw material, and liquid fuel raw material.

Example 1
According to the flow shown in FIG. 2, pyrolysis gasification of coal 860 t / day was performed.

  First, the atmospheric pressure preheating burner 12 using natural gas 28-2 as fuel was ignited, and preheating (heating) in the coal pyrolysis gasifier 1 was started. Since the pressure in the preheating section 5 during the preheating was almost normal pressure of 3 kPa (gauge pressure), the natural gas 28-2 and the combustion air 13 supplied to the preheating burner 12 were 0.5 MPa ( It was directly supplied from factory pipes 29 and 30 having a source pressure of (gauge pressure).

  After 12 hours after igniting the preheating burner 12, the indicated value of the thermometer installed on the ceiling portion in the gasification unit 2a is 1000 ° C. or more, and the indicated value of the thermometer installed at the pyrolysis reforming chamber 3 outlet is After confirming that the temperature reached 800 ° C., natural gas 28-1 and oxygen 11-1 were supplied to the slag tap burner 9, and the slag tap burner 9 was ignited. The supply ratio of the fuel (natural gas 28-1) and oxygen 11-1 at this time was adjusted so that the oxygen ratio was 1.0 (theoretical combustion oxygen amount).

  After confirming the ignition of the slag tap burner 9, the preheating burner 12 was extinguished. Immediately thereafter, boosting nitrogen 14 was added to the vicinity of the coal pyrolysis gasification furnace 1 outlet, and the pressure control valve 15 was controlled to start boosting.

When the pressure in the coal pyrolysis gasification furnace 1 reaches the target operating pressure (2.5 MPa, gauge pressure) after 2 hours from the start of the pressure increase, the introduction of the pressure-increasing nitrogen 14 is stopped and the gas Coal 16-1 (25 t / hr, pulverized coal = particle size 200 mesh or less, average 40 μm) and oxygen 11-2 (14000 Nm ³ / hr, purity 98%) were supplied into the chemical conversion unit 2a.

  Before supplying the coal 16-1 and the oxygen 11-2, the temperature in the gasification unit 2a (measured by a thermometer installed on the ceiling of the gasification unit 2a) was 300 ° C., but the coal 16− 1 and oxygen 11-2 were ignited without any problem, and it was possible to start the gasification reaction. In addition, the temperature in the gasification part 2a at the time of gasification implementation (normal time) was 1600 degreeC.

  After confirming that the gasification gas 18 generated from the gasification section 2a has been introduced into the pyrolysis reforming chamber 3, the supply of coal 16-2 (11 t / hr) to the pyrolysis reforming chamber 3 is started. did. In addition, the temperature in the thermal decomposition reforming chamber 3 at the steady state was 1050 ° C.

The process product 22 discharged from the coal pyrolysis gasification furnace 1 is subjected to separation and recovery of char, desulfurization, deammonia, and the like in the gas processing facility 23, and then the product gas 31 (57000 Nm) which is the final process product. ³ -dry / hr) and used as fuel gas for power generation. The separated and recovered char 25 (5 t / hr) was used as fuel in another boiler.

  In this example, no problem occurred even when coke oven gas (COG) containing mist derived from tar or sulfur was used as the fuel for the preheating burner 12.

(Example 2)
Pyrolysis gasification of coal 860 t / day was performed according to the flow shown in FIG.

  First, the atmospheric pressure preheating burner 12 using natural gas 28-2 as fuel was ignited, and preheating (heating) in the coal pyrolysis gasifier 1 was started. Since the pressure in the preheating section 5 during the preheating was almost normal pressure of 3 kPa (gauge pressure), the natural gas 28-2 and the combustion air 13 supplied to the preheating burner 12 were 0.5 MPa ( It was directly supplied from factory pipes 29 and 30 having a source pressure of (gauge pressure).

  12 hours after ignition of the preheating burner 12, the indicated value of the thermometer installed on the ceiling in the gasification unit 2a is 1000 ° C. or more, and the indication of the thermometer installed at the pyrolysis reforming chamber 3 outlet After confirming that the value reached 800 ° C., natural gas 28-1 and oxygen 11-1 were supplied to the slag tap burner 9, and the slag tap burner 9 was ignited. The supply ratio of the fuel (natural gas 28-1) and oxygen 11-1 at this time was adjusted so that the oxygen ratio was 1.0 (theoretical combustion oxygen amount).

  After confirming the ignition of the slag tap burner 9, the preheating burner 12 was extinguished. Immediately thereafter, the pressure-increasing nitrogen 14 was added into the gasification section 2a (added from the gasification burner 17 = also used for coal transportation nitrogen), and the pressure control valve 15 was controlled to start the pressure-increasing.

When the pressure in the coal pyrolysis gasifier 1 reaches the target operating pressure (2.5 MPa, gauge pressure) after 2 hours from the start of pressure increase, the introduction of the pressure increase nitrogen 14 is stopped and gasification is performed. Coal 16-1 (25 t / hr, pulverized coal = particle size 200 mesh or less, average 40 μm) and oxygen 11-2 (14000 Nm ³ / hr, purity 98%) were supplied into part 2a.

  The temperature in the gasification unit 2a before the supply of the coal 16-1 and oxygen 11-2 (a thermometer installed on the ceiling of the gasification unit 2a) Since the measurement was 200 ° C., the coal 16-1 and the oxygen 11-2 introduced into the gasification section 2a did not ignite.

  Therefore, immediately, when the supply amount of oxygen 11-1 in the slag tap burner 9 is increased to 1.2 as the oxygen ratio, the coal 16-1 and the oxygen 11-2 are ignited to start the gasification reaction. Became possible.

  In addition, after confirming that the gasification reaction started, the supply amount of oxygen 11-1 was changed again so that the oxygen ratio in the slag tap burner 9 was 1.0. In addition, the temperature in the gasification part 2a at the time of gasification implementation (normal time) was 1600 degreeC.

  After confirming that the gasification gas 18 generated from the gasification section 2a has been introduced into the pyrolysis reforming chamber 3, the supply of coal 16-2 (11 t / hr) to the pyrolysis reforming chamber 3 is started. did. In addition, the temperature in the thermal decomposition reforming chamber 3 at the steady state was 1050 ° C.

The process product 22 discharged from the coal pyrolysis gasification furnace 1 is subjected to separation and recovery of char, desulfurization, deammonia, and the like in the gas processing facility 23, and then the product gas 31 (57000 Nm) which is the final process product. ³ -dry / hr) and used as fuel gas for power generation. The separated and recovered char 25 (5 t / hr) was used as fuel in another boiler.

  In this example, no problem occurred even when coke oven gas (COG) containing mist derived from tar or sulfur was used as the fuel for the preheating burner 12.

(Comparative Example 1 [corresponding to Patent Document 5])
According to the flow shown in FIG. 4, pyrolysis gasification of coal 860 t / day was performed.

  The preheating burner 12 that uses natural gas 28-2 as a fuel is ignited to start preheating (heating) in the coal pyrolysis gasification furnace 1, and at the same time, nitrogen 14 for boosting is introduced into the gasification section 2a. By adding (added from the gasification burner 17) and performing control by the pressure regulating valve 15, pressure increase was also started.

  During the preheating, the pressure in the coal pyrolysis gasification furnace 1 including the preheating unit 5 changes from the normal pressure to the target pressure (2.5 MPa, gauge pressure) during operation. The natural gas 28-2 and the combustion air 13 supplied to the preheating burner 12 are supplied to 3.0 MPa by the compressors 32 and 33, respectively, with the gas supplied from the factory pipes 29 and 30 having an original pressure of 0.5 MPa. The pressure was increased up to.

  After 12 hours after igniting the preheating burner 12, the indicated value of the thermometer installed on the ceiling in the gasification section 2a is 600 ° C. or higher, and in addition, the pressure in the coal pyrolysis gasification furnace 1 is the target. After confirming that the operation pressure (2.5 MPa, gauge pressure) was reached, natural gas 28-1 and oxygen 11-1 were supplied to the slag tap burner 9, and the slag tap burner 9 was ignited. The supply ratio of the fuel (natural gas 28-1) and oxygen 11-1 at this time was adjusted so that the oxygen ratio was 1.0 (theoretical combustion oxygen amount).

After confirming the ignition of the slag tap burner 9, after extinguishing the preheating burner 12, into the gasification section 2a, coal 16-1 (25 t / hr, pulverized coal = particle size 200 mesh or less, average 40 μm) and oxygen 11 -2 (14000 Nm ³ / hr, purity 98%) was supplied, coal 16-1 and oxygen 11-2 ignited and gasification reaction was started. In addition, the temperature in the gasification part 2a at the time of gasification implementation (normal time) was 1600 degreeC.

  After confirming that the gasification gas 18 generated from the gasification unit 2a has been introduced into the pyrolysis reforming chamber 3, supply of coal 16-2 (11 t / hr) to the pyrolysis reforming chamber 3 is performed. Started. In addition, the temperature in the thermal decomposition reforming chamber 3 at the steady state was 1050 ° C.

The process product 22 discharged from the coal pyrolysis gasification furnace 1 is subjected to separation and recovery of char, desulfurization, deammonia, and the like in the gas processing facility 23, and then the product gas 31 (57000 Nm) which is the final process product. ³ -dry / hr) and used as fuel gas for power generation. The separated and recovered char 25 (5 t / hr) was used as fuel in another boiler.

  In Comparative Example 1, since the preheating burner was designed so that it could be used even during pressurization, the cost required for the preheating burner and the auxiliary equipment for the preheating burner increased five times as compared with the example.

(Comparative Example 2 [corresponding to Non-Patent Document 1])
An attempt was made to carry out pyrolysis gasification of coal 860 t / day according to the flow shown in FIG.

  First, the preheating burner 12 corresponding to the high pressure using the natural gas 28-2 as a fuel was ignited, and the preheating (temperature increase) in the coal pyrolysis gasification furnace 1 was started. Since the pressure in the preheating unit 5 during preheating was approximately 3 kPa at normal pressure, the natural gas 28-2 and the combustion air 13 supplied to the preheating burner 12 were each a factory having an original pressure of 0.5 MPa. It supplied directly from the piping 29 and 30.

  After 12 hours after igniting the preheating burner 12, it was confirmed that the indicated value of the thermometer installed on the ceiling in the gasification unit 2a reached 600 ° C. or higher, and then the slag tap burner 9 was supplied with natural gas 28− 1 and oxygen 11-1 were supplied, and the slag tap burner 9 was ignited. The supply ratio of the fuel (natural gas 28-1) and oxygen 11-1 at this time was adjusted so that the oxygen ratio was 1.0 (theoretical combustion oxygen amount).

  After confirming the ignition of the slag tap burner 9, the preheating burner 12 was extinguished. Then, coal 16-1 (25 t / hr, pulverized coal = particle size 200 mesh or less, average 40 μm) and oxygen 11-2 (14000 Nm 3 / hr, purity 98%) are supplied into the gasification unit 2a. At the same time as the gasification reaction was started, the pressurization nitrogen 14 was added to the vicinity of the outlet of the coal pyrolysis gasification furnace 1 and the pressure control valve 15 was controlled to start the pressure increase.

  Twenty minutes after the start of gasification, it was impossible to continue operation because clogging occurred in the vicinity of the coal pyrolysis gasification furnace outlet 1 with the internal pressure of the gasification section being 0.7 MPa. It was.

It is a figure which shows the process flow of this invention. It is a figure which shows the flow of the process and mass balance (test result) in an Example. It is a figure which shows the flow of the process and mass balance (test result) in an Example. It is a figure which shows the flow and mass balance (test result) of the process in a comparative example. It is a figure which shows the flow and mass balance (test result) of the process in a comparative example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Coal pyrolysis gasifier 2 Gasification chamber 2a Gasification part 3 Pyrolysis reforming chamber 4 Throat part 5 Preheating part 6 Slag tap 7 Slag pot 8 Slag 9 Slag tap burner 10-1 Fuel 10-2 Fuel 11-1 Oxygen 11-2 Oxygen 12 Preheating burner 13 Combustion air 14 Nitrogen for pressurization 15 Pressure regulating valve 16-1 Coal 16-2 Coal 17 Gasification burner 18 Gasification gas 19 Hydrogen-containing gas 20-1 Steam 20-2 Steam 21 Coal Nozzle 22 Process product 23 Gas treatment equipment 24 Gas quencher (quencher)
25 Char 26 Char recycling equipment 27 Process products 28-1 Natural gas 28-2 Natural gas 29 Factory piping (natural gas)
30 Factory piping (air)
31 Product gas 32 Compressor (natural gas)
33 Compressor (combustion air)

Claims (4)

It has a two-chamber, two-stage structure consisting of a lower gasification chamber having a preheating portion at the bottom and an upper pyrolysis reforming chamber connected to the gasification chamber via a throat portion, and the operating pressure is By using a coal pyrolysis gasification furnace having a pressure of 1 MPa (gauge pressure) or more and blowing one or two of coal and char together with oxygen into the gasification chamber to cause partial oxidation reaction. Gasification gas mainly containing carbon monoxide, water vapor, and carbon dioxide is generated, and coal is blown into the pyrolysis reforming chamber at the subsequent stage to reveal the gasification gas flowing from the gasification furnace. A method for operating a coal pyrolysis gasifier that uses heat to pyrolyze coal in the pyrolysis reforming chamber to produce gas, oil, and char,
When starting up the coal pyrolysis gasification furnace, first, using the preheating burner of normal pressure specifications installed in the preheating section, preheat the inside of the coal pyrolysis gasification furnace,
After stopping the preheating burner upon completion of the preheating, the pressure of the coal pyrolysis gasification furnace is then increased,
After completion of the pressurization, one or two kinds of coal and char are blown into the gasification part together with oxygen,
A method for operating a coal pyrolysis gasifier, wherein coal is blown into the pyrolysis reforming chamber.   The preheating unit is partitioned through a slag tap installed in the gasification chamber, and a slag tap burner for heating and keeping the slag tap is installed in the preheating unit. A method for operating a coal pyrolysis gasifier according to claim 1.   When the coal pyrolysis gasification furnace is started up, the slag tap burner is combusted, and after making the combustion exhaust gas generated by the combustion into a state containing unreacted oxygen, to the gasification unit, The method for operating a coal pyrolysis gasifier according to claim 2, wherein one or two of coal and char are blown together with oxygen.   The means for bringing unreacted oxygen into the combustion exhaust gas of the slag tap burner is that the amount of oxygen supplied to the slag tap burner is equal to or greater than the theoretical combustion oxygen amount. A method for operating a coal pyrolysis gasifier according to claim 3.

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