JP2009014644A - Method for analyzing tar in gas generated in gasification furnace and its system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To speedily and accurately grasp the concentration of tar at an operating site of a plant by a compact system constitution. <P>SOLUTION: A prescribed amount of generated gas introduced by a sample gas inlet pipe 2 is diluted by air introduced by an air inlet pipe 7 and introduced to a separation column 12 so that tar in the generated gas is separated by the separation column 12, and is adsorbed and held in the separation column 12. Air is passed through the separation column 12 to make the adsorbed and held tar flow out of the separation column 12 with air. The tar which has been made to flow out is burned by the action of an oxidation catalyst in a combustion chamber 18 to measure the amount of carbon dioxide generated by the combustion by a nondispersive infrared analyzer 19. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for analyzing tar in a gasification furnace product gas and an apparatus for measuring the amount of tar in a product gas obtained by gasifying biomass or the like in a gasification furnace.

  For example, the product gas obtained by gasifying biomass in a fluidized bed gasifier contains organic substances collectively called “tar”. This tar exists as a gas in the high temperature range, but causes a phase change to a solid in the low temperature range, causing damage to plants and gas utilization facilities (for example, generators and fuel cells such as gas engines and gas turbines). It becomes. In a fluidized bed gasification furnace, the main tar component that triggers this obstacle is naphthalene, but other polycyclic aromatic hydrocarbons that are slightly larger than naphthalene, such as acenaphthylene and phenanthrene, are also included.

  By the way, since the definition of “tar” is ambiguous, there are many methods for measuring the tar in the product gas. Non-Patent Document 1 describes a method shown for the purpose of internationally unifying this measurement method. In this method, as shown in FIG. 3, a sampling probe 51 for taking in the generated gas and a filter 52 connected to the rear end of the sampling probe 51 are provided. Particulate tar is collected. The sampling probe 51 and the filter 52 are heated so that tar does not condense on the way. The gaseous tar that has passed through the filter 52 is collected by a collection liquid (an organic solvent such as 2-propyl alcohol) in a plurality of cooled organic solvent traps 53, and the tar that has passed through the organic solvent trap 53 is solid-adsorbed. It is collected by the agent 54. In the figure, reference numeral 55 is a flow indicator, and 56 is a volume flow meter.

  The tar collected in the filter 52 and the solid adsorbent 54 in this way is extracted into an organic solvent (the same as the collected liquid) using a Soxhlet extractor or the like. Then, this extract and the collected liquid in the organic solvent trap 53 are mixed, the organic solvent is evaporated under predetermined temperature and pressure conditions, the weight of the evaporation residue is weighed, and this is used as the tar amount. . By dividing the value of the obtained tar amount by the sampling gas amount, the tar amount per gasification product gas amount can be obtained.

  Other conventional examples of the tar analysis method include a method using a flame ionization detector as shown in Non-Patent Document 2, and a gas chromatography and weight measurement method as shown in Patent Document 1. There are methods.

  However, since most tar analysis methods including the methods disclosed in Non-Patent Document 1 and Patent Document 1 are methods for analyzing samples by bringing them back to the laboratory, it takes several days until the results are known, There is a problem in reflecting it in the operation management of the plant. In addition, since most of these analysis methods are manually operated, there is a problem that operator skill is required to obtain highly reproducible results.

  On the other hand, the method using the flame ionization detector disclosed in Non-Patent Document 2 has a problem that the detection sensitivity differs depending on the target component, and also requires a hydrogen gas cylinder or a hydrogen gas generator in order to use hydrogen gas. Thus, there is a problem that the apparatus configuration becomes large.

Japanese Patent Laid-Open No. 61-2071 J. et al. P. A. Neft et al., “Guideline for Sampling and Analysis of Tar and Particles in Biomass Producer Gases”, Energy project EEN5-1999-00507, p. 1-46 O. Moersch et al., “Tar quantification with a new online analysis method”, Biomass and Bioenergy 18 (2000), p. 79-86

  The present invention has been made to solve such problems, and with a compact apparatus configuration, it is possible to quickly grasp the tar concentration at the plant operation site, and to improve the level of familiarity and proficiency between operators. It is an object of the present invention to provide a method and apparatus for analyzing tar in gasifier-produced gas that does not cause a measurement error based on the difference between the two.

In order to achieve the above object, a method for analyzing tar in a gasifier product gas according to the first invention comprises:
In a method for analyzing tar in a gasification furnace product gas that measures the amount of tar in the product gas obtained by gasification in a gasification furnace,
A certain amount of product gas is diluted with air and introduced into a separation column. The tar in the product gas is separated and absorbed and held in the separation column, and then air is passed through the separation column. Adsorbed and retained tar flows out of the separation column together with air, and the discharged tar is combusted by the action of an oxidation catalyst, and the amount of carbon dioxide produced by the combustion is measured to measure the amount of tar in the generated gas. It is characterized by this.

Further, the tar analyzer in the gasifier product gas according to the second invention is:
In the tar analyzer in the gasifier product gas that measures the amount of tar in the product gas obtained by gasification in the gasifier,
(A) a thermostatic chamber maintained at a constant temperature;
(B) a product gas introduction pipe for introducing the product gas into the thermostat;
(C) an air introduction pipe for introducing air into the thermostat;
(D) a product gas outlet pipe that guides the product gas out of the thermostat;
(E) a gas holder that is arranged in the thermostatic chamber and into which the product gas introduced by the product gas introduction pipe or the air introduced by the air introduction pipe is selectively introduced;
(F) Separation in which the air introduced into the thermostatic chamber and introduced by the air introduction pipe and the product gas in the gas holder are introduced, or only the air introduced by the air introduction pipe is introduced Columns,
(G) a processing gas outlet pipe for guiding the processing gas after passing through the separation column to the outside of the thermostat;
(H) The product gas arranged in the thermostat and introduced from the product gas introduction pipe passes through the gas holder and is led out of the thermostat through the product gas lead-out pipe, and the air introduction pipe A first operating position for passing the air introduced from the separation column through the separation gas to the outside of the thermostatic chamber via the processing gas lead-out pipe, and the product gas introduced from the product gas introduction pipe through the gas holder The air is led out of the thermostatic chamber through the product gas lead-out pipe without passing through the air, and the air introduced from the air introduction pipe passes through the gas holder and the separation column and passes through the processing gas lead-out pipe. A switching valve that is operated to switch between the second operation position leading out of the thermostat;
(I) a combustion chamber for burning tar in the processing gas discharged from the separation column by the action of an oxidation catalyst;
(J) An analyzer for measuring the amount of carbon dioxide derived from the combustion chamber.

  In the second aspect of the invention, the separation column may be a stainless steel tube or glass tube filled with diatomaceous earth coated with a dimethylsiloxane polymer (third invention).

  The product gas introduction tube is preferably heated to 100 ° C. to 350 ° C. (fourth invention). Moreover, it is preferable that a filter for removing dust in the product gas is inserted in the product gas introduction pipe (fifth invention). Further, it is preferable that a dilution nitrogen gas introduction pipe for diluting the production gas is connected to the production gas introduction pipe (sixth invention).

  It is preferable that a dehumidifying pipe for removing moisture in the air, a carbon dioxide trap for removing carbon dioxide in the air, and a carbon trap for removing organic substances in the air are interposed in the air introduction pipe (seventh invention). .

  According to the 1st invention or the 2nd invention, compared with the conventional wet collection method etc., the tar concentration in gasification furnace production gas can be grasped | ascertained quickly at the plant operation site. Moreover, since it is a mechanical method, there is no measurement error based on the difference between the operators and the proficiency level. Further, compared with the conventional technique using a flame ionization detector, hydrogen gas is not required, so a hydrogen gas cylinder or a hydrogen gas generator is not required, and the apparatus configuration can be made compact. Further, the detection sensitivity can be maintained regardless of the target component. As a result, a system useful for operation management of the tar treatment facility can be obtained.

  Next, a specific embodiment of a tar analysis method and apparatus therefor according to the present invention will be described with reference to the drawings.

  FIG. 1 is a system configuration diagram of a tar analyzer according to an embodiment of the present invention. The present embodiment is applied to an apparatus for measuring the amount of tar in a product gas obtained by gasifying biomass in a fluidized bed gasification furnace.

In the tar analyzer 1 of the present embodiment, a sample gas introduction pipe (product gas introduction pipe) 2 for introducing a sample gas from the produced gas is provided, and the produced gas taken in by the sample gas introduction pipe 2 is filtered. The filter 3 removes dust in the sample gas. Here, the sample gas introduction tube 2 is heated to 100 to 350 ° C. in order to avoid condensation of moisture and tar inside the conduit. A downstream side of the filter 3 is connected to a nitrogen gas introduction pipe 4 for mixing a nitrogen gas for diluting the sample gas. When the amount of tar in the sample gas is large, the flow rate adjusting valve 5 is opened and a known amount is opened. The sample gas is diluted by mixing the nitrogen gas for dilution. In this case, the nitrogen gas for dilution does not contain CO ₂ and organic substances.

Thereafter, the sample gas is introduced into the thermostatic chamber 6 maintained at a constant temperature. On the other hand, an air introduction pipe 7 for introducing air into the thermostat 6 is connected to the thermostat 6. Here, a dehumidifying tube 8 filled with silica gel or the like, a CO ₂ trap 9 filled with lithium hydroxide pellets or the like, and a carbon trap 10 filled with carbon molecular sieve or activated carbon are arranged in the middle of the air introduction tube 7. , moisture in the air is removed by the dehumidifying pipe 8, CO ₂ in the air is removed by CO ₂ trap 9, organic substances in the air are removed by the carbon trap 10. In this way, the purified air is introduced into the constant temperature bath 6. It should be noted that the dehumidifying tube 8, the CO ₂ trap 9, and the carbon trap 10 can be replaced with other devices having equivalent functions.

  In the thermostatic chamber 6, a gas holder 11 into which the sample gas introduced by the sample gas introduction tube 2 flows, a separation column 12 that adsorbs and holds tar in the sample gas, and the sample gas introduction tube 2 in the thermostatic chamber 6. A switching valve 13 comprising an eight-way switching valve for switching the direction of derivation of the sample gas introduced into 1 and the direction of derivation of the air introduced into the thermostat 6 by the air introduction pipe 7 is arranged. Further, in the thermostat 6, the sample gas introduced through the sample gas introduction pipe 2 is led out to the thermostat 6, and the processing gas after passing through the separation column 12 is taken out of the thermostat 6. A processing gas lead-out pipe 15 to be led out is connected. A flow rate adjusting valve 16 and a suction pump 17 are inserted in the sample gas outlet pipe 14. Further, the separation column 12 is a stainless tube or glass tube filled with diatomaceous earth coated with a dimethylsiloxane polymer.

The processing gas outlet pipe 15 is connected to a combustion chamber 18. The combustion chamber 18 burns inflowing tar and converts it into carbon dioxide (CO ₂ ) by the action of the oxidation catalyst. Thereafter, the carbon dioxide is introduced into the non-dispersive infrared analyzer 19 to measure its concentration, and the air is exhausted through the flow rate adjusting valve 20 and the suction pump 21.

  As shown also in FIG. 2, the switching valve 13 has eight ports (first port 13a to eighth port 13h), and the air introduction pipe 7 is connected to the first port 13a. The sample gas inlet tube 2 is connected to the third port 13c, the sample gas outlet tube 14 is connected to the fourth port 13d, and the processing gas outlet tube 15 is connected to the seventh port 13g. Further, the second port 13b and the fifth port 13e are connected by a first bypass pipe 22, and the gas holder 11 is inserted in the middle of the first bypass pipe 22, and between the eighth port 13h and the sixth port 13f. Are connected by a second bypass pipe 23, and the separation column 12 is inserted in the middle of the second bypass pipe 23.

  Next, a procedure for measuring the amount of tar in the sample gas using the tar analyzer 1 having the above-described configuration will be described.

  First, by operating the switching valve 13, as shown in FIG. 2A, the second port 13b and the third port 13c, the fourth port 13d and the fifth port 13e, the sixth port 13f and the seventh port 13g. In a state where the eighth port 13h and the first port 13a communicate with each other, the sample gas maintained at a constant temperature is introduced into the thermostatic chamber 6 from the sample gas introduction pipe 2. The dust in the sample gas is removed by the filter 3 before being introduced into the thermostatic chamber 6. When the amount of tar in the sample gas is large, the flow rate adjusting valve 5 is opened to mix a known amount of nitrogen gas for dilution to dilute the sample gas.

  Thus, the sample gas introduced into the thermostatic chamber 6 is taken into the gas holder 11 from the third port 13c of the switching valve 13 via the second port 13b and the first bypass pipe 22, and then the fifth port 13e. And it is exhausted from the sample gas outlet pipe 14 via the fourth port 13d. Here, the pressure in the gas holder 11 is read, and when the pressure is less than the atmospheric pressure, dilution nitrogen gas may be introduced from the nitrogen gas introduction pipe 4 to adjust the pressure.

The air supplied through the air inlet pipe 7, the water is removed by dehumidifier tube 8, the CO ₂ trap 9 CO ₂ is removed, after the organic matter has been cleaned are removed by the carbon trap 10, It is introduced into the thermostat 6. Thus, the air introduced into the thermostat 6 reaches the separation column 12 from the first port 13a of the switching valve 13 via the eighth port 13h and the second bypass pipe 23. When the air passes through the separation column 12, the tar retained in the separation column 12 is eluted and flows out to the subsequent stage through the sixth port 13f and the seventh port 13g together with the air. Note that the separation column 12 needs to be replaced periodically according to the frequency of use.

  When the tar-eluting air is introduced into the combustion chamber 18, the tar is burned and converted into carbon dioxide by the action of the oxidation catalyst in the combustion chamber 18, and this carbon dioxide concentration is introduced into the non-dispersive infrared analyzer 19. And its concentration is measured. When the measured carbon dioxide concentration is plotted against the time axis, one or a plurality of peak values are obtained, so the total value of all peak areas detected within a predetermined time is obtained. Since the total peak area has a correlation with the amount of carbon derived from tar, the amount of carbon derived from tar is obtained with reference to a calibration curve obtained in advance. Then, the carbon concentration derived from tar in the sample gas can be obtained by dividing the obtained carbon amount by the sample gas amount. The amount of sample gas introduced into the non-dispersive infrared analyzer 19 is determined by the capacity of the gas holder 11, but when the pressure in the gas holder 11 is not atmospheric pressure, it is necessary to perform pressure correction.

  After a predetermined time has elapsed, the switching valve 13 is switched, and as shown in FIG. 2B, the twelfth port 13a and the second port 13b, the third port 13c and the fourth port 13d, the fifth port 13e and the sixth port 13f and the seventh port 13g communicate with the eighth port 13h.

At this time, the air introduced through the air introduction pipe 7 reaches the gas holder 11 from the first port 13 a of the switching valve 13 via the second port 13 b and the first bypass pipe 22, and is held in the gas holder 11. The sample gas flows into the separation column 12 through the fifth port 13e and the sixth port 13f together with the sample gas. Thus, in the separation column 12, tar in the sample gas is adsorbed and held in the column, while low-boiling point hydrocarbons (methane, ethylene, etc.), CO, and CO ₂ are not held in the column, but the second bypass pipe 23, It flows to the subsequent stage via the eighth port 13h and the seventh port 13g, and is exhausted after being combusted in the combustion chamber 18.

  On the other hand, the sample gas introduced into the thermostatic chamber 6 from the sample gas introduction pipe 2 is exhausted from the sample gas outlet pipe 14 through the third port 13c and the fourth port 13d.

  Thereafter, the switching valve 13 is switched again to the position shown in FIG. In this manner, the switching valve 13 is alternately switched between the position shown in FIG. 2A and the position shown in FIG. 2B, so that the sample gas in the gas holder 11 is introduced into the separation column 12 together with the air and is contained in the sample gas. The tar is absorbed and held in the separation column 12, and thereafter, only air passes through the separation column 12, whereby the retained tar is eluted into the air and the tar is burned in the combustion chamber 18 alternately. Will be done. The separated tar is burned by the action of the oxidation catalyst, and the amount of tar in the sample gas can be measured by measuring the amount of carbon dioxide generated by the combustion.

According to tar analysis method of the present embodiment, since the measuring the CO ₂ concentration to oxidize the target component, regardless of the target component, the advantage that it is possible to obtain a response which is substantially proportional to the number of carbon atoms is there. Moreover, since the amount of tar components contained in the product gas can be measured quasi-continuously on-site, it can be quickly reflected in the operation management of the plant. For example, feedback to scrubber operating conditions, judgment of replacement cycle of sawdust filter and activated carbon tower, adjustment of operating conditions for reforming and combustion treatment, and further adjustment of operating conditions of gasifier Can do.

  In this embodiment, although what was applied to the apparatus which measures the tar amount in the product gas obtained by gasifying biomass with a fluidized-bed gasification furnace was demonstrated, this invention is fuel other than biomass, for example, coal gas It can also be applied to a chemical reactor. Moreover, it is applicable also to gasification furnaces other than a fluidized bed gasification furnace. In these cases, it is necessary to obtain a correlation between the response of the apparatus of the present embodiment and another method (wet collection-weight method) in advance.

The system block diagram of the tar analyzer which concerns on one Embodiment of this invention. Operation explanatory diagram showing FIG. 1 partially enlarged System configuration diagram showing conventional tar measurement method

Explanation of symbols

1 Tar analyzer 2 Sample gas introduction pipe (product gas introduction pipe)
3 filter 4 nitrogen gas inlet pipe 6 thermostatic bath 7 air inlet tube 8 dehumidifying pipe 9 CO ₂ trap 10 carbon trap 11 gas holder 12 the separation column 13 the switching valve 14 sample gas lead tube (product gas outlet pipe)
15 Processing gas outlet pipe 18 Combustion chamber 19 Non-dispersive infrared analyzer (analyzer)
22 1st bypass pipe 23 2nd bypass pipe

Claims (7)

In a method for analyzing tar in a gasification furnace product gas that measures the amount of tar in the product gas obtained by gasification in a gasification furnace,
A certain amount of product gas is diluted with air and introduced into a separation column. The tar in the product gas is separated and absorbed and held in the separation column, and then air is passed through the separation column. Adsorbed and retained tar flows out of the separation column together with air, and the discharged tar is combusted by the action of an oxidation catalyst, and the amount of carbon dioxide produced by the combustion is measured to measure the amount of tar in the generated gas. A method for analyzing tar in a gasification furnace product gas characterized by the above. In the tar analyzer in the gasifier product gas that measures the amount of tar in the product gas obtained by gasification in the gasifier,
(A) a thermostatic chamber maintained at a constant temperature;
(B) a product gas introduction pipe for introducing the product gas into the thermostat;
(C) an air introduction pipe for introducing air into the thermostat;
(D) a product gas outlet pipe that guides the product gas out of the thermostat;
(E) a gas holder that is arranged in the thermostatic chamber and into which the product gas introduced by the product gas introduction pipe or the air introduced by the air introduction pipe is selectively introduced;
(F) Separation in which the air introduced into the thermostatic chamber and introduced by the air introduction pipe and the product gas in the gas holder are introduced, or only the air introduced by the air introduction pipe is introduced Columns,
(G) a processing gas outlet pipe for guiding the processing gas after passing through the separation column to the outside of the thermostat;
(H) The product gas arranged in the thermostat and introduced from the product gas introduction pipe passes through the gas holder and is led out of the thermostat through the product gas lead-out pipe, and the air introduction pipe A first operating position for passing the air introduced from the separation column through the separation gas to the outside of the thermostatic chamber via the processing gas lead-out pipe, and the product gas introduced from the product gas introduction pipe through the gas holder The air is led out of the thermostatic chamber through the product gas lead-out pipe without passing through the air, and the air introduced from the air introduction pipe passes through the gas holder and the separation column and passes through the processing gas lead-out pipe. A switching valve that is operated to switch between the second operation position leading out of the thermostat;
(I) a combustion chamber for burning tar in the processing gas discharged from the separation column by the action of an oxidation catalyst;
(J) An apparatus for analyzing tar in a gasifier product gas, comprising an analyzer for measuring the amount of carbon dioxide derived from the combustion chamber.   The tar analysis device in the gasification furnace product gas according to claim 2, wherein the separation column is obtained by filling a diatomaceous earth coated with a dimethylsiloxane polymer into a stainless steel tube or a glass tube.   The tar analysis device in gasification furnace product gas according to claim 2 or 3 in which said product gas introduction pipe is heated at 100 ° C-350 ° C.   The tar analysis device in gasifier product gas according to any one of claims 2 to 4, wherein a filter for removing dust in the product gas is inserted in the product gas introduction pipe.   The tar analyzer in gasifier product gas according to any one of claims 2 to 5, wherein a dilution nitrogen gas introduction tube for diluting the product gas is connected to the product gas introduction tube.   The dehumidifying pipe for removing moisture in the air, a carbon dioxide trap for removing carbon dioxide in the air, and a carbon trap for removing organic substances in the air are interposed in the air introduction pipe. The tar analysis apparatus in the gasification furnace production | generation gas in any one.

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