JP5591158B2 - COS processing apparatus and COS processing method in product gas - Google Patents

Description

  The present invention relates to a COS treatment apparatus and a COS treatment method in product gas.

  In recent years, effective use of low-quality fuels such as coal and heavy oil has been demanded from the viewpoint of diversification in which not only high-quality fossil fuels but also low-quality fossil fuels are actively used. In the field of thermal power generation, from the viewpoint of improving power generation efficiency, combined power generation using a gas turbine that uses gas fuel and a steam turbine, and power generation that introduces hydrocarbon gas into a fuel cell are becoming widespread. Therefore, research and development has been conducted to gasify low-quality fuel and use it for power generation.

  By the way, low-quality fuel generally contains a lot of sulfur compounds, and when gasified from this is burned as it is, the sulfur compounds are discharged as sulfur oxides from the chimney to the atmosphere and become a source of environmental destruction such as acid rain. . Therefore, in ordinary thermal power generation, it is put into practical use to install a flue gas desulfurization device in the downstream of the boiler and remove the sulfur compound as gypsum, for example. However, in combined power generation, corrosion of the material is remarkable because the inlet temperature of the gas turbine is higher than the temperature of the boiler in ordinary thermal power generation. Therefore, it is necessary to remove various impurities including sulfur compounds in the upstream rather than the downstream of the gas turbine to protect the material, and the flue gas desulfurization apparatus cannot be applied. In fuel cell power generation, it is essential to secure power generation efficiency and durability by protecting materials, and various impurities must be removed in the upstream of the fuel cell as well.

As a method for removing the impurities, a so-called wet gas purification process in which water-soluble components are removed with a water scrubber and H ₂ S (hydrogen sulfide) is removed with an aqueous solution of amines has been put into practical use. However, H ₂ S can be removed with an aqueous solution of amines, but carbonyl sulfide (COS) cannot be removed. Therefore, a hydrolysis reaction represented by the formula (1) is performed using a COS conversion catalyst to promote a reaction for conversion into a form of H ₂ S that can be removed with an aqueous solution of amines.
COS + H ₂ O → H ₂ S + CO ₂ (1)

  Here, as a COS conversion catalyst, for example, a catalyst containing titania, a catalyst containing alumina, a group IV metal and barium, or a catalyst containing an alkali metal, chromium oxide and alumina is known (Patent Document 1).

JP 2004-75712 A

  By the way, when the COS content increases or decreases depending on the operation of the gasification gas, or when the desired COS conversion rate is not reached when the catalytic function is lowered, the downstream side piping, gas turbine, etc. There is a problem that the equipment is corroded.

In addition, when COS is not decomposed, it is not decomposed by the desulfurization device, and is emitted as SO ₂ when it is burned by, for example, a gas turbine. As a result, there is a risk of high concentrations of sulfur oxides being discharged into the environment.
Here, when undegraded COS occurs, there is a problem that it is impossible to grasp whether the cause is a transient increase in the concentration of COS in the product gas or whether the conversion capability of the COS conversion device itself is insufficient. .

  Conventionally, gas is collected and then analyzed by gas chromatograph analysis. However, the analysis requires several minutes, and the response is low, so that there is a problem that measurement in seconds cannot be performed.

  Therefore, when the transient concentration of COS in the gasification gas increases or when the conversion in the COS converter is insufficient, the situation is detected quickly and continuously in seconds, and prompt action is taken. Is anxious.

  In view of the above problems, the present invention can detect the situation in real time when the concentration of COS in the product gas increases or the COS converter is insufficiently converted, and can take prompt measures. It is an object of the present invention to provide a COS processing apparatus and a COS processing method.

  A first invention of the present invention for solving the above-described problem is a first COS converter having a COS catalyst for treating a product gas containing carbonyl sulfide (COS), and a front of the first COS converter. A laser analyzer for measuring the COS concentration in the product gas, and when the COS concentration exceeds a threshold as a result of the measurement by the laser analyzer, the product gas flow path is bypassed from the main flow path. A channel switching means for switching to the channel, a second COS converter having a COS catalyst disposed in the bypass channel and treating the produced gas containing carbonyl sulfide (COS), and the determined COS concentration is a threshold concentration And a control device that performs control to switch the flow path switching means to the bypass flow path side and process unconverted COS (carbonyl sulfide) with the second COS converter. In COS processor in the product gas.

  According to a second invention, in the first invention, a laser analyzer is provided on the downstream side of the first COS converter, and measures a COS concentration in the product gas subjected to the COS conversion process. In the COS treatment device in the product gas.

  According to a third aspect of the present invention, there is provided the COS treatment apparatus in the produced gas, wherein the temperature of the internal gas of the first COS converter is measured from the relative intensity of the absorbance of the produced gas component. is there.

  According to a fourth aspect of the present invention, in the third aspect of the invention, the COS treatment apparatus in the produced gas is characterized in that when the internal gas of the first COS converter is low as a result of temperature measurement, control is performed to increase heat It is in.

  According to a fifth invention, in the first invention, the laser analyzer irradiates the first measurement unit for introducing the laser beam into the generated gas, and the semiconductor laser beam from the semiconductor laser device to the first measurement unit, And a first detector that measures the COS concentration in the fuel gas by laser absorption spectroscopy.

  In a sixth aspect of the present invention, the COS treatment device in the product gas of the second invention is provided in parallel with two systems (first system and second system), and the two systems of COS treatment devices are alternately used to produce the product gas. When the COS concentration is measured, the COS concentration on the downstream side of the first COS converter is measured while the COS conversion process is performed by the first COS converter of the first system, and the COS conversion leakage occurs. The COS-converted product gas containing unprocessed COS is returned via a return line that returns from the downstream side of the first COS converter of the first system to the upstream side of the first COS converter of the second system. The COS processing method is characterized in that it is introduced into a first COS converter of the second system, and COS conversion processing is performed by the first COS converter.

  According to the present invention, when the concentration of COS in the product gas increases or when the conversion in the COS converter is insufficient, the situation can be detected in real time, and a prompt action can be taken.

FIG. 1 is a schematic diagram of a COS treatment device in product gas according to a first embodiment. FIG. 2 is a schematic diagram of a COS treatment apparatus in the product gas according to the second embodiment. FIG. 3 is a schematic diagram of a COS treatment apparatus in another product gas according to the second embodiment. FIG. 4A is a schematic diagram of the COS treatment apparatus in the product gas according to the third embodiment. FIG. 4-2 is a schematic diagram of a COS treatment device in another product gas according to the third embodiment. FIG. 5 is a schematic diagram of a COS treatment device in another product gas according to the third embodiment. FIG. 6 is a relationship diagram between the signal intensity of the CO gas absorbance and the rotation amount index (J). FIG. 7 is an absorption spectrum intensity diagram of the energy of pump light in the R branch at vibrational transitions at temperatures of 300K and 400K.

  Hereinafter, the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments. In addition, constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art or those that are substantially the same.

A COS treatment apparatus in product gas according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram of a COS treatment device in product gas according to a first embodiment.
As shown in FIG. 1, the COS treatment apparatus 10A in the product gas according to this embodiment includes a first COS converter 13A having a COS catalyst for treating the product gas 12 containing carbonyl sulfide (COS), and the first COS converter 13A. When the COS concentration exceeds the threshold as a result of the measurement by the laser analyzer 15A that is provided on the upstream side of the COS converter 13A and measures the COS concentration in the product gas 12, and the laser analyzer 15A, A flow path switching means 19 for switching the flow path of the product gas from the main flow path L ₁ to the bypass flow path L ₂ , and a COS catalyst that is interposed in the bypass flow path L ₂ and processes the generated gas 12 containing carbonyl sulfide (COS) When the obtained COS concentration (X) exceeds the threshold concentration (Y), the flow path switching means 19 is switched to the bypass flow path L ₂ side, and the second COS converter 13B having COS change And a control unit 20 for controlling to process the unconverted COS (carbonyl sulfide) in vessel 13B, those comprising a desulfurization unit 21 for removing sulfur oxides in the product gas 12.

The gasification furnace 11 is a known one, for example, a low quality fuel such as coal or heavy oil and oxygen, air, or oxygen-enriched air that is a gasifying agent, and a product gas that is a gasification gas. 12 is taken out.
It is desirable to remove dust from the extracted product gas 12 using a known dust collector. The COS contained in the product gas 12 from which the dust has been removed is subjected to COS conversion processing using the first COS converter 13A.
In this embodiment, a laser analyzer 15A that measures the COS concentration in the product gas 12 is provided on the upstream side of the first COS converter 13A.

Here, the laser analyzer 15A includes a first measurement unit 17A that introduces semiconductor laser light (hereinafter referred to as “laser light”) 14 into the generated gas 12, and a laser from the semiconductor laser device 16 to the first measurement unit 17A. And a first detector 18A that irradiates light 14 and measures the COS concentration in the fuel gas by laser absorption spectroscopy.
Note that the reference laser absorption light (I ₀ ) is detected by the second detector 18B, and the measurement error caused by the wavelength shift of the semiconductor laser is calibrated.
The wavelength of the semiconductor laser is, for example, 1.0 to 6.0 μm, and more preferably the measurement wavelength is 1.65 μm.

In the first detector 18A, the COS concentration contained in the product gas 12 is measured online, and it is confirmed whether or not the first COS converter 13A is within an allowable range where COS conversion is possible.
Then, when a predetermined threshold is set and it is determined that it is not within the allowable range, the control device 20 operates the flow path switching means 19 so that the first COS converter 13A interposes the flow path of the product gas 12. switching from the main flow path L ₁ which is the bypass flow path L _2, the second COS converter 13B interposed in the bypass flow path L _2, so that the untreated and had been carbonyl sulfide (COS) to catalytic treatment I have to.

That is, normally, the produced gas 12 containing COS within a predetermined COS processing capacity range (several tens of ppm to several thousand ppm) flows, but due to an upstream problem such as fuel or the gasifier 11, the COS content In the second COS converter 13B interposed in the bypass flow path L ₂ because the COS catalyst processing capacity is exceeded and COS flows to the downstream side as it is. By performing the COS process, the leakage of unprocessed COS to the downstream side is eliminated.
Further, when the concentration of COS is large, it is possible to take measures to reduce the COS concentration by handling the operation of the gasification furnace 11.

  The gas composition in the product gas 12 can be confirmed by laser analysis using a semiconductor laser.

  According to the COS treatment apparatus in the product gas of the present embodiment, when the transient increase in COS concentration in the product gas 12 from the gasification furnace 11 or the conversion in the COS converter is insufficient, the situation is determined in seconds. It is possible to detect quickly and continuously in units, and to take quick measures.

A COS treatment apparatus in product gas according to an embodiment of the present invention will be described with reference to the drawings. FIG. 2 is a schematic diagram of a COS treatment apparatus in the product gas according to the second embodiment.
As shown in FIG. 2, the COS treatment device 10B in the product gas according to the present embodiment is provided on the downstream side of the first COS converter 13A in the COS treatment device 10A in the product gas of the first embodiment. The laser analyzer 15B for measuring the COS concentration in the COS conversion processing gas 12 is provided.
The laser analyzer 15B irradiates the second measurement unit 17B with the semiconductor laser light 14 from the semiconductor laser device 16 on the downstream side of the first COS converter 13A, and the COS concentration in the fuel gas by laser absorption spectroscopy. And a second detector 18B for measuring the COS concentration in the product gas 12 after COS conversion.
By measuring the COS concentration on the downstream side, it can be determined whether or not the processing capability of the COS catalyst is normal.

  That is, when the amount of COS measured on the upstream side of the first COS converter 13A is equal to or smaller than a predetermined value, it is determined that the COS concentration is measured on the downstream side because deterioration of the COS catalyst is a factor. Can do.

  Also, by applying the present invention, simultaneous measurement at a plurality of points can be performed with a single device, so that the status of the COS conversion capability of the COS processing device can be accurately grasped.

In such a case, by operating the passage switching means 19 by the control device 20, bypass passage to the flow path of the product gas 12 from the main flow path L ₁ of the first COS converter 13A is interposed L switching to _2, the second COS converter 13B interposed in the bypass flow path L _2, are untreated and had been carbonyl sulfide (COS) such that catalytic treatment.

FIG. 3 is a schematic diagram of a COS treatment apparatus in another product gas according to the second embodiment. As shown in FIG. 3, the COS conversion devices of the present embodiment are provided in two systems (first system, second system) 13A-1 and 13A-2 in parallel, and these two systems of COS processing apparatuses 13A-1 and 13A- The COS conversion process is performed using 2 alternately.
When continuously processing the COS in the product gas 12, the COS conversion processing is performed by the first COS converter 13A-1 of the first system, and the downstream side of the first COS converter 13A-1 is processed. When the COS concentration is measured by the laser analyzer 15B-1 and a COS conversion leakage occurs, the first COS converter 13A of the second system from the downstream side of the first COS converter 13A-1 of the first system. -2 through the return line L ₁₁ returning to the upstream side of -2, the COS-converted product gas 12 containing unprocessed COS is introduced into the first COS converter 13A-2 of the second system, and the first The COS converter 13A-2 performs COS conversion processing.
In FIG. 3, reference numerals L _1-1 and L _1-2 are main flow paths, L _2-2 is a bypass flow path, L ₁₂ is a return line, 19-1 and 19-2 are flow path switching means, and 15B-2 is Each of the laser analyzers is illustrated.

Thus, when two systems of COS processing devices are provided during continuous operation, COS can be processed using another system of COS processing devices that have been suspended during normal maintenance.
As a result, even if any trouble or the like occurs in the second COS converter 13B-1, leakage of COS to the downstream side can be eliminated.

A COS treatment apparatus in product gas according to an embodiment of the present invention will be described with reference to the drawings. FIG. 4A is a schematic diagram of the COS treatment apparatus in the product gas according to the third embodiment. FIG. 4-2 is a schematic diagram of a COS treatment device in another product gas according to the third embodiment.
FIG. 5 is a schematic diagram of a COS treatment device in another product gas according to the third embodiment.
As illustrated in FIG. 4A, the COS treatment device 10C-1 in the product gas according to the present embodiment further measures the temperature inside the first COS converter 13A in the COS treatment device 10B of the second embodiment. The laser analyzer 15C is provided.

In this embodiment, the gas temperature inside the first COS converter 13A is measured from the relative intensity of the absorbance of components (CO, CH ₄ , CO _2, etc.) contained in the product gas 12.

  In this embodiment, the absorbance of the component contained in the product gas component is measured, and the temperature in the gas is measured in light of a temperature curve measured in advance.

Here, in the laser analyzer 15C, a semiconductor laser beam 14 is introduced into the product gas 12 to measure the COS concentration and the fourth detector that measures the absorbance of the gas composition (for example, CO) of the product gas 12. 18D.
The semiconductor laser beam 14 shares the laser beam from the semiconductor laser device 16.

As a result, the temperature in the gas inside the first COS converter 13A can be measured. As a result, it can be confirmed whether the inside of the first COS converter 13A is properly maintained at the catalytic reaction temperature.
Therefore, when there is an increase in the COS concentration on the downstream side, it can be confirmed whether the catalyst is deteriorated or the catalyst reaction temperature is low.
When the catalyst reaction temperature is low, control for increasing the temperature so as to reach an appropriate catalyst reaction temperature (for example, 200 to 300 ° C.) by a heating means (not shown) can be performed by a control means (not shown).

FIG. 6 is a graph showing the relationship between the fluorescence intensity of CO gas and the rotational quantum number (J). In FIG. 6, black circles are measured values at 300K, and square marks are measured values at 400K. The line connecting these plots is a fitting using the following formula (1).
This chart is a vibration-rotation spectrum from the ground state to the first vibration excited state in the electronic state.

  FIG. 7 is a diagram of the absorption spectrum intensity of the energy of pump light in the R branch in the vibration transition at temperatures of 300K and 400K.

The relative intensity corresponding to the rotational quantum number (J) of this spectral line is measured, and the temperature of the measurement field can be calculated from the measurement result by applying the following formula (1) as a function of temperature.
N _j / N _{j = 0} = (2J + 1) exp (− [(kcBJ) · (J + 1)] / (kT)) (1)
here,
N _j : Number of molecules in the rotational quantum number J (number density)
N _{j = 0} : total number of molecules J: rotational quantum number k: Boltzmann constant c: speed of light B: rotational constant T: temperature (rotational temperature)
It is.

Therefore, for example, the peak of 300K R (5) and R (20) in FIG. 6 is selected, signal intensity is obtained by absorption from CO, and fitting of a known Boltzmann distribution of CO is performed. Concentration and temperature can be predicted.
As a result, in the past, for example, the internal temperature measurement in a thermocouple or the like was a spot temperature measurement, but the average temperature of the entire measurement field (the entire optical path length of the laser beam) can be obtained without contact. . Thereby, the temperature of the whole COS catalyst can be grasped.

In this embodiment, the laser beam 14 from the semiconductor laser 16 is shared. However, as in the COS treatment apparatus 10C-2 in the generated gas shown in FIG. A semiconductor laser device 16A and a second semiconductor laser device 16B for temperature measurement may be provided, and each measurement may be performed by separate laser sources.
This is because the measured value of the COS concentration in the product gas 12 is about several hundred ppmV, whereas the measured value of the CO concentration is as high as 10,000 ppmV or higher, so that the measurement signal can be acquired. This is because it becomes easy.

In this embodiment, an example is shown in which the absorbance of CO present at a high concentration in coal gas is applied, but temperature measurement is performed using other coal gas components (CH ₄ , CO _2, etc.) as indices. Is also applicable.

In the COS treatment apparatus 10D in the product gas shown in FIG. 5, the temperature is also measured at the center in the first COS converter 13A having the COS catalyst and at the front and rear portions thereof.
Then, an average catalyst temperature may be obtained by measuring the inlet temperature side and the outlet temperature side inside the first COS converter 13A. In this case, the temperature measurement at the center may be omitted.
Thereby, since the temperature inside the catalyst of the first COS converter 13A can be monitored, it can be maintained at an appropriate catalyst temperature condition, and COS catalyst conversion can be performed appropriately.

  In addition, like the COS processing apparatus 10C-2 in the generated gas of FIG. 4B, a second semiconductor laser 16B for temperature measurement may be separately installed, and only temperature measurement may be separately performed.

  As described above, according to the present invention, when the concentration of COS in the product gas is increased or when the conversion in the COS converter is insufficient, the situation can be detected in real time, and prompt action can be taken. Therefore, it becomes possible to appropriately carry out emission management of sulfur oxides.

10A to 10D COS treatment device in product gas 12 Product gas 13A First COS converter 13B Second COS converter 15A to 15C Laser analyzer 19 Flow path switching means 20 Control device

Claims (6)

A first COS converter having a COS catalyst for treating a product gas comprising carbonyl sulfide (COS);
A laser analyzer provided on the upstream side of the first COS converter and measuring the COS concentration in the product gas;
As a result of measurement by the laser analyzer, when the COS concentration exceeds a threshold value, a flow path switching means for switching the flow path of the product gas from the main flow path to the bypass flow path;
A second COS converter having a COS catalyst interposed in the bypass channel and treating a product gas containing carbonyl sulfide (COS);
A control device that controls to switch the flow path switching means to the bypass flow path side and process unconverted COS (carbonyl sulfide) in the second COS converter when the obtained COS concentration exceeds the threshold concentration; And a COS treatment apparatus in the product gas. In claim 1,
A COS treatment apparatus in a product gas, comprising a laser analyzer provided on a downstream side of the first COS converter and measuring a COS concentration in a product gas subjected to a COS conversion process. In claim 1,
A COS treatment apparatus in a product gas, wherein the temperature of the internal gas of the first COS converter is measured from the relative intensity of the absorbance of the product gas component. In claim 3,
As a result of temperature measurement, when the internal gas of the first COS converter is low, control is performed to increase the heat. In claim 1,
Laser analyzer
A first measurement unit for introducing laser light into the product gas;
A first detector that irradiates the first measurement unit with semiconductor laser light from the semiconductor laser device and measures the COS concentration in the fuel gas by laser absorption spectroscopy. COS processing device. The COS treatment device in the product gas of claim 2 is provided in parallel in two systems (first system, second system),
When processing the COS in the product gas by alternately using these two COS processing devices,
While the COS conversion process is performed by the first COS converter of the first system, the COS concentration on the downstream side of the first COS converter is measured, and when a COS conversion leakage occurs,
The COS-converted product gas containing unprocessed COS is returned via a return line that returns from the downstream side of the first COS converter of the first system to the upstream side of the first COS converter of the second system. A COS processing method comprising introducing a first COS converter of a second system and performing a COS conversion process by the first COS converter.

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