JP6143632B2 - Component analysis method for low ash samples - Google Patents

Description

  The present invention relates to a component analysis method for low ash samples such as biomass fuel and coke fuel with low ash content.

  In thermal power plants, there are plans for new construction and remodeling of plants that can grasp the environmentally regulated substances discharged outside the system in detail and clear the regulations, and in order to establish this process, trace amounts in fuel, wastewater, and exhaust gas It is essential to understand the behavior of the components. Under such circumstances, with the diversification of fuels, for example, cases of using petroleum coke, biomass, mixed coal (coal and petroleum coke) as fuels are increasing, and establishment of an analysis method is urgently required.

  As an analysis method of elements of coal fuel, which is frequently used as fuel for thermal power plants, official methods (JIS M8811 (fuel pretreatment), JIS K 0116 compliant (ash composition analysis), JIS K 0102 (Hg, As analysis)) ) Is defined (Non-Patent Documents 1 to 3).

JIS M8811 JIS K 0116 JIS K 0102

However, in petroleum coke fuel, biomass fuel, mixed coal (mixed fuel of coal and petroleum coke), etc. with low ash content, etc., in the analysis method by the official method (Non-Patent Documents 1 to 3) defined in conventional coal fuel analysis, There are the following problems.
1) Since the ash content in the fuel is as low as 10% or less, it takes a lot of time and money to adjust the ash sample required for analysis using the conventional JIS method, and it cannot be practically adopted.
2) In addition, there is scattering of volatile components at the time of ashing of the sample, and further, when preparing the sample, the recovery rate of trace components due to molten chloride and carbonate formation is reduced.

  When ashing in a calcination furnace using, for example, petroleum coke fuel as a solid fuel, the ash ashing at 815 ° C of JIS standard clearly reveals the problem of ash recovery failure due to volatilization of trace elements and melting of low melting point substances. Further, even when ashing is performed at about 500 ° C., there is a problem that volatilization loss or the like occurs depending on trace elements.

  Further, as a solid fuel, for example, when ashing in a baking furnace using biomass fuel, even when ashing at 600 ° C. lower than JIS regulations, for example, carbonate remains and the ashing treatment does not proceed sufficiently. There is a problem.

3) Further, even if the analysis can be performed, since it is in the vicinity of the analysis detection lower limit value of the trace component, there is a problem that the analysis accuracy is deteriorated (analysis variation is, for example, 50%).

4) Furthermore, since the time required for analysis (ashing, analysis sample preparation, analysis) is long (7 days / case or more), there is a problem that the behavior of trace components cannot be fed back to the plant operation in a timely manner.

  In view of the above problems, the present invention provides a component analysis method for a low ash sample that has high accuracy and can be quickly analyzed in ash analysis of biomass fuel, coke fuel, mixed fuel of coal and petroleum coke, etc. with low ash content. Is an issue.

  The first invention of the present invention for solving the above-described problem is that solid fuel having an ash content of 10% by weight or less when ashing the solid fuel is used, and the constituent elements in the ash sample are: It is classified as an element with a loss rate of 20% or higher when ashing at a high temperature of 500 ° C or higher, or an element with a loss rate of less than 20%. 1) When analyzing an element with a loss rate of 20% or higher The solid fuel is subjected to oxygen plasma low-temperature ashing treatment, then liquefied, adjusted to a liquefied sample, and then subjected to elemental analysis. 2) When analyzing elements with a loss rate of less than 20% In the method of component analysis of a low ash sample, the solid fuel is subjected to microwave low-temperature ashing treatment, then liquefied, and a liquefied sample is prepared, followed by elemental analysis.

  According to the present invention, when grasping the ash concentration of the low ash fuel, the solid fuel is classified into a component that easily volatilizes and a component that does not easily volatilize. Using plasma low-temperature ashing, ashing is performed under mild conditions. If the loss rate is less than 20%, the ashing is performed using microwave low-temperature ashing. Since the analysis is performed according to the properties of each constituent element by performing the liquefaction treatment, the accuracy of the analysis is improved.

  A second invention is the oxygen plasma low-temperature ashing treatment according to the first invention, wherein the oxygen plasma low-temperature ashing treatment is performed by separating the solid fuel sample into an analysis dish and performing low-temperature ashing at 250 ° C. or lower for a predetermined time while flowing oxygen. A component analysis method for a low ash sample characterized by obtaining a predetermined amount of ash.

  According to the present invention, when the loss rate that easily volatilizes is 20% or more, the ash content without ashing loss can be obtained by performing ashing under mild low-temperature ashing conditions using oxygen plasma low-temperature ashing. Can be obtained.

  According to a third invention, in the first invention, the microwave low-temperature ashing treatment is performed by separating the solid fuel sample into a container, performing microwave low-temperature ashing at a temperature of 550 ° C. or lower for a predetermined time, It is in the component analysis method of the low ash sample characterized by obtaining ash.

  According to the present invention, when the loss rate that is difficult to volatilize is less than 20%, ashing is performed by using a microwave low-temperature ashing treatment at a higher temperature than the oxygen plasma low-temperature ashing treatment. Ash content can be obtained by performing an ashing treatment with a shortened time.

  A fourth invention is characterized in that, in the first invention, the liquefaction treatment is performed by putting ash and acid in a sealed container and heating while performing microwave treatment for a predetermined time, thereby obtaining a liquefied sample. It is in the component analysis method of the low ash sample.

  According to the present invention, when the sample is liquefied, the sealed type is used. Therefore, even when the element ratio is a trace component, the scattering can be prevented.

  A fifth invention is characterized in that, in the first invention, the liquefaction treatment is performed by putting ash and acid into an open container and heating the solution while performing microwave treatment for a predetermined time to obtain a liquefied sample. It is in the component analysis method of the low ash sample.

  According to the present invention, when the ratio of elements is large at the time of liquefaction for sample preparation, even open liquefaction can be applied.

  A sixth invention is a component analysis method for a low ash sample, characterized in that in the fourth or fifth invention, after liquefaction treatment, solid phase extraction treatment is performed.

  According to the present invention, a liquid sample is concentrated by a solid-phase extraction resin, so that a trace component is concentrated, and a trace component can be analyzed with high accuracy.

  A seventh invention is the component analysis method for a low ash sample according to the sixth invention, wherein the solid phase extraction treatment is performed by a two-stage solid phase extraction method.

  According to the present invention, when a liquid sample is extracted, the solid phase extraction resin is arranged in two stages in series, whereby the main component is concentrated in the first stage solid phase part and the trace component is concentrated in the second stage solid phase part. By obtaining a sample from which main components are separated, analysis with higher analytical sensitivity becomes possible.

  According to an eighth invention, in any one of the first to seventh inventions, the solid fuel is a biomass fuel, a petroleum coke fuel, or a mixed fuel of coal and petroleum coke, and a component analysis of a low ash sample Is in the way.

  ADVANTAGE OF THE INVENTION According to this invention, the trace component in the ash of the low ash content of biomass fuel, petroleum coke fuel, or the mixed fuel of coal and petroleum coke as a solid fuel can be analyzed with sufficient sensitivity.

  According to the present invention, when grasping the ash concentration of the low ash fuel, it is classified into a component that easily volatilizes and a component that does not easily volatilize. If the loss rate is less than 20%, it is ashed using microwave low-temperature ashing, and then liquefied. Thus, the analysis accuracy can be improved, the analysis time can be shortened, and the analysis error can be greatly improved. Thereby, an elemental analysis result can be reflected on a plant operation index.

1 is an analysis process diagram of a component analysis method for a low ash sample according to Example 1. FIG. FIG. 2 is an analysis process diagram of the component analysis method for the low ash sample according to the second embodiment. FIG. 3 is an analysis process diagram of the component analysis method for the low ash sample according to the third embodiment. FIG. 4 is an analysis process diagram of the component analysis method for the low ash sample according to Example 4. FIG. 5 is an analysis process diagram of a component analysis method for a low ash sample according to Example 5. FIG. 6 is a diagram showing the element content ratio in ash of coal fuel, petroleum coke fuel, and biomass (hardwood) fuel.

  Exemplary embodiments and examples of the present invention will be described below in detail with reference to the accompanying drawings. In addition, this invention is not limited by this embodiment and an Example, Moreover, when there are two or more Examples, what comprises and combines each Example is also included.

  The component analysis method of the low ash sample according to the present invention is a fuel composition of petroleum coke fuel and biomass fuel, and in order to solve the above-mentioned problems of ashing treatment caused by the ash composition, Paying attention to the amount of ash, if the amount of ash when ashing the solid fuel at a high temperature of, for example, 500 ° C. is 10% by weight (preferably 5% by weight) or less, Analysis is performed by an analysis method.

  Furthermore, the element of the constituent component in the ash sample is an element having a loss rate of 20% or more when ashing at a high temperature of 500 ° C. or higher (an element that is easily lost due to volatilization / solidification), or the loss rate is less than 20%. The ashing conditions are selected by classifying them into elements (elements that are difficult to lose due to volatilization and solidification).

Here, as an example of conditions for high-temperature ashing at 500 ° C. or higher, for example, coke fuel is preferably ashed at 500 ° C., and biomass fuel is preferably ashed at 600 ° C.
Here, the ashing temperature is set to 500 ° C. or more because if it is less than 500 ° C., it takes a lot of time for the combustion decomposition (ashing) of the hydrocarbon content in the fuel, and it takes a lot of analysis time. .
The upper limit of the ashing temperature is preferably about 815 ° C., for example.

Next, further ashing conditions are selected based on the behavior of the elements in the ash that has been ashed.
That is, the loss rate when elements of trace components in the ash sample are incinerated at a high temperature of 500 ° C. or higher is 20% or more as “elements that are easily lost due to volatilization / solidification”, and the loss rate is 20%. The elements below are classified as “elements that are difficult to lose due to volatilization / solidification”.
When ashing at a predetermined temperature in advance, the difference between the ashing element before ashing and after ashing is confirmed for the constituent elements in the fuel, and the threshold of the loss rate is confirmed in advance as 20%.

  And when analyzing an element having a loss rate of 20% or more, after performing an oxygen plasma low-temperature ashing treatment on the solid fuel, and then performing a liquefaction treatment (wet acid dissolution treatment) to prepare a liquefied sample, I do elemental analysis.

This oxygen plasma low-temperature ashing process uses an oxygen plasma low-pressure ashing device, dispenses a solid fuel sample (predetermined amount) into an analysis dish, performs low-temperature ashing at 250 ° C. or lower while introducing oxygen, The ash content is obtained.
Here, as an example of the ashing conditions, it is desirable to perform the ashing treatment at 150 to 250 ° C. for 2 to 10 hours while flowing 100% oxygen gas into the apparatus at, for example, about 100 mL / min.

  According to the present oxygen plasma low-temperature ashing treatment, when an element having a loss rate of 20% or more that is likely to volatilize is analyzed, the oxygen plasma low-temperature ashing treatment is used to carry out ashing treatment under mild low-temperature ashing conditions. As a result, it is possible to obtain an ash without ashing loss.

  In contrast, when analyzing elements with a loss rate of less than 20%, solid-state fuel is subjected to microwave low-temperature ashing (stricter ashing than oxygen plasma low-temperature ashing), and then liquefaction ( Wet acid dissolution treatment), and after preparing the liquefied sample, elemental analysis is performed.

  In this microwave low-temperature ashing treatment, a solid fuel sample (predetermined amount) is dispensed into a container (for example, quartz fiber crucible or platinum crucible) using a microwave dry ashing device, and ashed at 550 ° C. or lower. To obtain a predetermined amount of ash.

  Here, as an example of the ashing conditions, it is desirable that the ashing process is performed by raising the temperature at 100 ° C./min and holding the temperature at 550 ° C. or lower for 30 to 60 minutes.

In this microwave low-temperature ashing, if the volatility of trace elements is high, it is preferable to control the temperature stepwise as compared with the ashing treatment at a constant temperature because it has a scattering prevention effect.
On the other hand, as a method for reducing the ashing temperature and shortening the time, ashing can be performed by a fluidization (fluidized bed) method of the sample, which is effective.

  According to the microwave low-temperature ashing treatment, when the loss rate that is difficult to volatilize is less than 20%, the microwave low-temperature ashing treatment is used to perform the ashing treatment under conditions higher than the oxygen plasma low-temperature ashing treatment. Thus, the ash content can be obtained by performing the ashing process with a shortened ashing time.

Next, a liquefaction treatment is performed as a sample adjustment of the obtained ash.
Also in this liquefaction treatment, conditions are selected according to the proportion of constituent elements in the ash.
As the first liquefaction treatment, the liquefaction treatment is performed by putting ash in a sealed container.
In this sealed liquefaction treatment, for example, using a microwave wet ashing apparatus, ash and acid are introduced into a sealed container, and microwave treatment (for example, 13.56 MHz, high frequency 100 W) is performed for a predetermined time. For example, the temperature is raised to 200 ° C. to obtain a liquefied sample.
Here, as the acid for acid treatment, for example, acids such as nitric acid / concentrated hydrochloric acid and hydrofluoric acid, and other acids such as hydrogen peroxide and perchloric acid can be used.

  According to this process, since it is a sealed type when liquefying the sample preparation, even when the element ratio is a trace component, the scattering can be prevented.

As a 2nd liquefaction process, ash is put into an open container and it liquefies.
In this open type liquefaction treatment, ash and acid are introduced into an open type container using a microwave wet ashing apparatus, and microwave treatment (for example, 13.56 MHz, high frequency 100 W) is performed for a predetermined time. The temperature is raised to 0 ° C. to obtain a liquefied sample.

  This open-type second liquefaction treatment can be applied when the constituent ratio of the element is large, and the liquefaction time can be shortened as compared with the first liquefaction treatment.

Here, the difference in the composition ratio of the elements of the solid fuel will be described with reference to FIG.
FIG. 6 is an example showing the content ratio of elements in ash of coal fuel, petroleum coke fuel, and biomass (hardwood) fuel. The horizontal axis indicates constituent elements and the vertical axis indicates the ratio (%).
As shown in FIG. 6, since the biomass fuel is derived from a plant, the ratio of elements such as Ca and K is large. However, since the petroleum coke fuel is derived from a mineral, the ratio of V, Ni and the like is large.

  Therefore, based on the difference in the solid fuel, the main element is specified and the first liquefaction process or the second liquefaction process is selected.

Depending on the composition ratio, the sample after liquefaction may be analyzed as it is by an analyzer, or it may be necessary to further extract trace elements.
In the case of this microanalysis, after the liquefaction process, a solid phase extraction process is further performed. In this solid-phase extraction process, for example, after adsorbing with a molecular recognition type resin, an elution process is performed under predetermined conditions to elute a desired element.

  Here, as the extraction resin for the solid phase extraction treatment, for example, a molecular recognition type solid phase extraction resin having an imino-2-acetic acid group is preferably used. As a molecular recognition type solid phase extraction resin having an imino-2-acetic acid group, for example, “InertSEP (trade name)” manufactured by GL Sciences Inc. can be exemplified.

  By performing this solid phase extraction treatment, the trace component is concentrated in the liquid sample by the solid phase extraction resin, and the analysis of the trace component with high accuracy becomes possible.

  If the analysis accuracy of trace elements decreases due to the influence of main elements during this solid-phase extraction process, solid-phase extraction is performed by concentrating trace components by the two-stage solid-phase extraction method in which the solid-phase part is arranged in two stages in series. It is preferable to carry out.

By placing the solid phase extraction resin in two stages in series and introducing a liquid sample, the main components are concentrated in the first stage solid phase part, the trace components are concentrated in the second stage solid phase part, and the main components are separated. By obtaining the obtained sample, analysis with higher analytical sensitivity becomes possible.
When, for example, petroleum coke fuel is analyzed as the fuel, the main components V, Ni and the like are extracted in the first stage solid phase portion, and the trace components P, Be and the like are extracted in the second stage solid phase portion.
That is, the main elements V and Ni are adsorbed in the first stage solid phase part, and the trace components are transferred to the second stage solid phase part and adsorbed in the second stage solid phase part. Thereafter, an eluate is flowed to elute the target trace element, and trace components such as Sb and Sn are extracted. When elution is performed, water or a buffer solution may be flowed once to remove impurities, and a cleanup process may be performed.

The liquefied sample after the liquefaction treatment is subjected to qualitative and quantitative analysis of each element by a known elemental analysis means.
Here, the analysis of the solid fuel is preferably performed by, for example, an inductively coupled plasma (ICP) mass spectrometer (hereinafter, “ICP mass spectrometer”), an ICP emission spectrometer, an atomic absorption spectrometer, or the like.

  According to the present invention, when grasping the ash concentration of the low ash fuel, the solid fuel is classified into a component that easily volatilizes and a component that does not easily volatilize. Using plasma low-temperature ashing, ashing is performed under mild conditions. If the loss rate is less than 20%, the ashing is performed using microwave low-temperature ashing. Since the analysis is performed according to the properties of each constituent element by performing the liquefaction treatment, the accuracy of the analysis is improved.

1 is an analysis process diagram of a component analysis method for a low ash sample according to Example 1. FIG.
As shown in FIG. 1, the component analysis method for a low ash sample according to the present embodiment includes a sample receiving step 11, a sample pretreatment step 12, an oxygen plasma low temperature ashing treatment step 13, a wet dissolution treatment step 14, and an analysis sample preparation. It consists of the process 15 and the elemental analysis process 16.
In this embodiment, an element having a loss rate of 20% or more (an element that is easily lost due to volatilization / solidification) is an object, and an analysis of a trace element having a small constituent ratio is an object.

  In the sample pretreatment step 12, the sample is reduced, pulverized, and the particle size is adjusted according to JISM8811.

In the oxygen plasma low-temperature ashing treatment step 13, ashing is performed using a pretreated sample using an oxygen plasma low-temperature ashing apparatus (for example, “lab JPA300 type (trade name)” manufactured by J-Science).
First, 10 g of a sample (petroleum coke) is fractionated into a quartz dish (or a Pyrex (registered trademark) glass dish) so as to be uniform and smooth.
As ashing conditions, 100% oxygen gas is allowed to flow in the apparatus at about 100 mL / min for 4 hours or more at 200 ° C. An ash content of 0.5 g of this ashing treatment was obtained.
Compared with the conventional ashing time, the time can be shortened by 1/2, and the cost can be greatly reduced.
Since the amount of ashed sample is determined by the ash concentration, a large amount of ashing can be achieved by installing a plurality of quartz dishes in the apparatus.

In the wet dissolution treatment step 14, a Teflon (registered trademark) sealed vessel (φ20 mm) is placed in a microwave wet ashing apparatus (for example, “MARS6 (trade name)” manufactured by CEM / Japan) in order to convert dry ashed ash into a solution. × 100 mmH), 0.5 g ash and 10 ml of nitric acid were added, and the temperature was raised to 200 ° C. with microwaves (13.56 MHz, high frequency 100 W) for 15 minutes.
In addition, when the solution is incomplete, the acid species and the liquid amount are appropriately selected. Because of the hermetically sealed type, trace elements that easily volatilize can be reliably liquefied.

In the analytical sample preparation step 15, the completely liquefied liquid is diluted and fixed in volume (250 ml) with a 0.1N nitric acid solution, and the analytical sample is prepared. In the elemental analysis step 16, a trace component is analyzed by, for example, an ICP mass spectrometer.
Here, as an ICP mass spectrometer, for example, analysis was performed using “ICP-MS 7500CX type (trade name)” manufactured by Agilent Technologies.
Typical analysis conditions of the ICP mass spectrometer include, for example, high frequency output: 1.6 kW, torch observation height: 7.5 mm, carrier gas: 0.9 L / min, makeup gas: 0.3 L / min, reaction Gas (He gas: 5 ml / min, H ₂ gas: 4.5 ml / min) was used.

  According to the analysis in Example 1, for example, petroleum coke fuel could analyze Ba as an element, and biomass fuel could analyze B, Ba, and Pb as elements.

FIG. 2 is an analysis process diagram of the component analysis method for the low ash sample according to the second embodiment.
As shown in FIG. 2, the component analysis method for the low ash sample according to the present embodiment includes a sample receiving step 11, a sample pretreatment step 12, an oxygen plasma low-temperature ashing treatment step 13, a wet dissolution treatment step 14, and a solid phase extraction. The process 17 includes an analysis sample preparation process 15 and an element analysis process 16.
In this embodiment, an element with a loss rate of 20% or more (an element that is easily lost due to volatilization / solidification) is targeted, and an analysis of trace elements with a very small constituent ratio is targeted.

  In the sample pretreatment step 12, the sample is reduced, pulverized, and the particle size is adjusted according to JISM8811.

In the oxygen plasma low-temperature ashing treatment step 13, ashing is performed using a pretreated sample using an oxygen plasma low-temperature ashing apparatus (for example, “lab JPA300 type (trade name)” manufactured by J-Science).
First, 10 g of a sample (petroleum coke) is fractionated into a quartz dish (or a Pyrex (registered trademark) glass dish) so as to be uniform and smooth.
As ashing conditions, 100% oxygen gas is allowed to flow in the apparatus at about 100 mL / min for 4 hours or more at 200 ° C. An ash content of 0.5 g of this ashing treatment was obtained.
Compared with the conventional ashing time, the time can be shortened by 1/2, and the cost can be greatly reduced.
Since the amount of ashed sample is determined by the ash concentration, a large amount of ashing can be achieved by installing a plurality of quartz dishes in the apparatus.

In the wet dissolution treatment step 14, a Teflon (registered trademark) sealed vessel (φ20 mm) is placed in a microwave wet ashing apparatus (for example, “MARS6 (trade name)” manufactured by CEM / Japan) in order to convert dry ashed ash into a solution. × 100 mmH), 0.5 g ash and 10 ml of nitric acid were added, and the temperature was raised to 200 ° C. by microwave for 15 minutes (13.56 MHz, high frequency 100 w).
In addition, when the solution is incomplete, the acid species and the liquid amount are appropriately selected. Because of the hermetically sealed type, trace elements that easily volatilize can be reliably liquefied.

The solid phase extraction step 17 is a step added to Example 1, in which the liquefied sample is solid phase extracted and concentrated by the two-stage solid phase extraction method of the solid phase extraction method (molecular recognition type) to adjust the analysis sample. did.
As a result, the solid-phase extraction enabled the element concentration to be 2 to 10 times that of the conventional method, and the analysis lower than the conventional analytical quantification lower limit (1/2 to 1/10) or less was enabled.
By this solid phase extraction, in the case of petroleum coke fuel, it is possible to concentrate at a high concentration without being affected by the disturbing components (V, Ni, S) of the main elements, and it is possible to detect a trace amount component.

In the analytical sample preparation step 15, the completely liquefied liquid is diluted and fixed in volume (250 ml) with a 0.1N nitric acid solution, and the analytical sample is prepared. In the elemental analysis step 16, a trace component is analyzed by, for example, an ICP mass spectrometer.
As an ICP mass spectrometer, for example, “ICP-MS 7500CX type (trade name)” manufactured by Agilent Technologies was used.
As typical analysis conditions of the ICP mass spectrometer, for example, high frequency output: 1.6 KW, torch observation height: 7.5 mm, carrier gas: 0.9 L / min, makeup gas: 0.3 L / min, reaction gas (He Gas: 5 ml / min, H ₂ gas: 4.5 ml / min).

  According to the analysis of Example 2, for example, petroleum coke fuel could analyze Sb, Sn, As, Se, Pb, and B as elements, and biomass fuel could analyze Sb, Sn, As, and Se as elements. .

FIG. 3 is an analysis process diagram of the component analysis method for the low ash sample according to the third embodiment.
As shown in FIG. 3, the component analysis method of the low ash sample according to the present embodiment includes a sample receiving step 11, a sample pretreatment step 12, a microwave low temperature ashing treatment step 18, a wet dissolution treatment step 14, and an analysis sample preparation. It consists of the process 15 and the elemental analysis process 16.
In the present embodiment, an element with a loss rate of less than 20% (an element that is difficult to lose due to volatilization / solidification) is targeted, and the analysis of trace elements with a very small constituent ratio is targeted.

  In the sample pretreatment step 12, the sample is reduced, pulverized, and the particle size is adjusted according to JISM8811.

In the microwave low-temperature ashing treatment step 18, 50 g of a sample (petroleum coke) is added to a quartz fiber in a microwave dry ashing device (manufactured by CEM-Japan, “Phenix type (trade name)”) using the pretreated sample. Aliquoted into a type crucible (100 mL). The ashing device was heated at 100 ° C./min, and ashing conditions were microwaved (13.56 MHz, high frequency 100 w) at 500 ° C. for 50 minutes. As a result of the ashing treatment, an ash content of 0.5 g was obtained. The ashing time can be shortened by about 1/5 from the conventional ashing time, which leads to a reduction in ashing cost.
Since the amount of ashed sample is determined by the ash concentration, a large amount of ashing can be achieved by installing a plurality of quartz dishes in the apparatus.

In the wet dissolution treatment step 14, a Teflon (registered trademark) sealed vessel (φ20 mm) is placed in a microwave wet ashing apparatus (for example, “MARS6 (trade name)” manufactured by CEM / Japan) in order to convert dry ashed ash into a solution. × 100 mmH), 0.5 g ash and 10 ml of nitric acid were added, and the temperature was raised to 200 ° C. by microwave for 15 minutes (13.56 MHz, high frequency 100 w).
In addition, when the solution is incomplete, the acid species and the liquid amount are appropriately selected. Because of the hermetically sealed type, it is possible to reliably liquefy the recovery of trace elements that tend to volatilize.

In the analytical sample preparation step 15, the completely liquefied liquid is diluted and fixed in volume (250 ml) with a 0.1N nitric acid solution, and the analytical sample is prepared. In the elemental analysis step 16, a trace component is analyzed by, for example, an ICP mass spectrometer.
Here, as an ICP mass spectrometer, for example, analysis was performed using “ICP-MS 7500CX type (trade name)” manufactured by Agilent Technologies.
Typical analysis conditions of the ICP mass spectrometer are, for example, high frequency output: 1.6 kW, torch observation height: 7.5 mm, carrier gas: 0.9 L / min, makeup gas: 0.3 L / min, reaction gas ( He gas: 5 ml / min, H ₂ gas: 4.5 ml / min).

  According to the analysis of Example 3, for example, in petroleum coke fuel, the elements are Na, K, Ca, Mg, Co, Zn, Si, Al, Fe, Ti, Li, S, Mo, Cr, Mn, Cu, Zr. In the case of biomass fuel, Na, Mg, P, Zn, Cd, Si, Al, Fe, Ti, Li, S, Mo, Cr, Mn, Cu, Zr, Sr, and Ag are analyzed as biomass elements. I was able to.

FIG. 4 is an analysis process diagram of the component analysis method for the low ash sample according to Example 4.
As shown in FIG. 4, the component analysis method of the low ash sample according to the present embodiment includes a sample receiving step 11, a sample pretreatment step 12, a microwave low-temperature ashing treatment step 18, a wet dissolution treatment step 14, and an analysis sample preparation. It consists of the process 15 and the elemental analysis process 16.
In this example, an element with a loss rate of less than 20% (an element that is difficult to lose due to volatilization / solidification) is targeted, and analysis of elements with a major constituent ratio is targeted.

  In the sample pretreatment step 12, the sample is reduced, pulverized, and the particle size is adjusted according to JISM8811.

In the microwave low-temperature ashing treatment step 18, a sample (petroleum coke) is added to a microwave dry ashing device (manufactured by CEM-Japan, “Phenix type (trade name)”) using the pretreated sample.
50 g was dispensed into a quartz fiber crucible (100 mL). The ashing device was heated at 100 ° C./min, and ashing conditions were microwaved (13.56 MHz, high frequency 100 w) at 500 ° C. for 50 minutes. As a result of the ashing treatment, an ash content of 0.5 g was obtained. The ashing time can be shortened by about 1/5 from the conventional ashing time, which leads to a reduction in ashing cost.
Since the amount of ashed sample is determined by the ash concentration, a large amount of ashing can be achieved by installing a plurality of quartz dishes in the apparatus.

In the wet dissolution treatment step 14, an open vessel (φ20 mm) made of Teflon (registered trademark) is used in a microwave wet ashing apparatus (for example, “MARS6 (trade name)” manufactured by CEM / Japan) in order to make dry ashed ash into a solution. × 100 mmH), 0.5 g ash and 10 ml of nitric acid were added, and the temperature was raised to 200 ° C. by microwave for 15 minutes (13.56 MHz, high frequency 100 w).
In addition, when the solution is incomplete, the acid species and the liquid amount are appropriately selected.

In the analytical sample preparation step 15, the completely liquefied liquid is diluted and fixed in volume (250 ml) with a 0.1N nitric acid solution, and the analytical sample is prepared. In the elemental analysis step 16, a trace component is analyzed by, for example, an ICP mass spectrometer.
Here, as an ICP mass spectrometer, for example, analysis was performed using “ICP-MS 7500CX type (trade name)” manufactured by Agilent Technologies.
Typical analysis conditions of the ICP mass spectrometer are, for example, high frequency output: 1.6 kW, torch observation height: 7.5 mm, carrier gas: 0.9 L / min, makeup gas: 0.3 L / min, reaction gas ( He gas: 5 ml / min, H ₂ gas: 4.5 ml / min).

  According to the analysis of Example 4, for example, petroleum coke fuel could analyze Ni and V as main elements, and biomass fuel could analyze K and Ca as main elements.

FIG. 5 is an analysis process diagram of a component analysis method for a low ash sample according to Example 5.
As shown in FIG. 5, the component analysis method of the low ash sample according to the present embodiment includes a sample receiving step 11, a sample pretreatment step 12, a microwave low temperature ashing treatment step 18, a wet dissolution treatment step 14, a solid phase extraction. The process 17 includes an analysis sample preparation process 15 and an element analysis process 16.
In this example, an element with a loss rate of less than 20% (an element that is difficult to lose due to volatilization / solidification) is targeted, and analysis of trace elements with a constituent ratio is targeted.

  In the sample pretreatment step 12, the sample is reduced, pulverized, and the particle size is adjusted according to JISM8811.

In the microwave low-temperature ashing treatment step 18, 50 g of a sample (petroleum coke) is added to a quartz fiber in a microwave dry ashing device (manufactured by CEM-Japan, “Phenix type (trade name)”) using the pretreated sample. -Aliquoted into crucible (100 mL). The ashing device was heated at 100 ° C./min, and ashing conditions were microwaved (13.56 MHz, high frequency 100 w) at 500 ° C. for 50 minutes. As a result of the ashing treatment, an ash content of 0.5 g was obtained. The ashing time can be shortened by about 1/5 from the conventional ashing time, which leads to a reduction in ashing cost.
Since the amount of ashed sample is determined by the ash concentration, a large amount of ashing can be achieved by installing a plurality of quartz dishes in the apparatus.

In the wet dissolution treatment step 14, a Teflon (registered trademark) sealed vessel (φ20 mm) is placed in a microwave wet ashing apparatus (for example, “MARS6 (trade name)” manufactured by CEM / Japan) in order to convert dry ashed ash into a solution. × 100 mmH), 0.5 g ash and 10 ml of nitric acid were added, and the temperature was raised to 200 ° C. by microwave for 15 minutes (13.56 MHz, high frequency 100 w).
In addition, when the solution is incomplete, the acid species and the liquid amount are appropriately selected. Because of the hermetically sealed type, it is possible to reliably liquefy the recovery of trace elements that tend to volatilize.

The solid phase extraction step 17 is a step added to Example 4, in which the liquefied sample is subjected to solid phase extraction by the solid phase extraction method (molecular recognition type) two-stage solid phase extraction method and concentrated to adjust the analysis sample. did.
As a result, the solid-phase extraction enabled the element concentration to be 2 to 10 times that of the conventional method, and the analysis lower than the conventional analytical quantification lower limit (1/2 to 1/10) or less was enabled. By this solid phase extraction, in the case of petroleum coke fuel, it is possible to concentrate at a high concentration without being affected by the disturbing components (V, Ni, S) of the main elements, and it is possible to detect a trace amount component.

In the analytical sample preparation step 15, the completely liquefied liquid is diluted and fixed in volume (250 ml) with a 0.1N nitric acid solution, and the analytical sample is prepared. In the elemental analysis step 16, a trace component is analyzed by, for example, an ICP mass spectrometer.
As an ICP mass spectrometer, for example, “ICP-MS 7500CX type (trade name)” manufactured by Agilent Technologies was used.
As typical analysis conditions of the ICP mass spectrometer, for example, high frequency output: 1.6 KW, torch observation height: 7.5 mm, carrier gas: 0.9 L / min, makeup gas: 0.3 L / min, reaction gas (He Gas: 5 ml / min, H ₂ gas: 4.5 ml / min).

  According to the analysis of Example 5, for example, petroleum coke fuel could analyze P, Be, and Cd as elements, and biomass fuel could analyze Be, Co, Ni, and V as elements.

As described above, by combining the first to fifth embodiments, the ash concentration in the fuel can be grasped, and in particular, the trace element analysis time can be shortened, the analysis cost can be reduced, and the analysis value variation can be reduced. . By combining analysis methods that match the behavior of ash elements in this way, the analysis time can be reduced from 7 days / cases to 2 days / cases and 5 days / cases, and the analysis error is within 10% (conventional) Was 50%), and the analysis accuracy could be improved.
Thereby, an elemental analysis result can be reflected on a plant operation index.

11 Sample acceptance process 12 Sample pretreatment process 13 Oxygen plasma low-temperature ashing process 14 Wet dissolution process 15 Analytical sample preparation process 16 Elemental analysis process

Claims (8)

Using solid fuel having an ash content of 10% by weight or less when ashing the solid fuel,
The element of the constituent component in the ash sample is classified into an element having a loss rate of 20% or more when ashing at a high temperature of 500 ° C. or higher, or an element having a loss rate of less than 20%.
1) When analyzing elements with a loss rate of 20% or more,
The solid fuel is subjected to oxygen plasma low-temperature ashing, and then liquefied,
After adjusting the liquefied sample, elemental analysis,
2) When analyzing elements with a loss rate of less than 20%,
The solid fuel is subjected to microwave low-temperature ashing treatment, and then liquefied,
A component analysis method for a low ash sample, wherein elemental analysis is performed after preparing a liquefied sample. In claim 1,
The oxygen plasma low-temperature ashing treatment is
Sample the solid fuel into an analysis dish,
A component analysis method for a low ash sample, characterized in that low temperature ashing at 250 ° C. or lower is performed for a predetermined time while flowing oxygen to obtain a predetermined amount of ash. In claim 1,
The microwave low-temperature ashing treatment is
Dispensing a sample of the solid fuel into a container;
A component analysis method for a low ash sample, characterized by performing microwave low-temperature ashing at a temperature of 550 ° C. or lower for a predetermined time to obtain a predetermined amount of ash. In claim 1,
A component analysis method for a low ash sample, characterized in that liquefaction is performed by putting ash and acid into a sealed container and heating the mixture while performing microwave treatment for a predetermined time to obtain a liquefied sample. In claim 1,
A component analysis method for a low ash sample, characterized in that liquefaction is performed by putting ash and acid into an open container and heating the sample while performing microwave treatment for a predetermined time to obtain a liquefied sample. In claim 4 or 5,
A component analysis method for a low ash sample, characterized by performing solid phase extraction after liquefaction. In claim 6,
A component analysis method for a low ash sample, wherein the solid phase extraction treatment is performed by a two-stage solid phase extraction method. In any one of Claims 1 thru | or 7,
A method for analyzing a component of a low ash sample, wherein the solid fuel is biomass fuel, petroleum coke fuel, or a mixed fuel of coal and petroleum coke.

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