JPS6171356A - Nitrogen analysis method of coal - Google Patents

Abstract

PURPOSE:To analyze nitrogen in a stable state, by mixing a specified amount of mixed agent of soda lime, alumina and iron oxide including water with a coal sample, heating the mixture at 430+ or -20 deg.C for a specified time period, decomposing the mixture at 950-1,000 deg.C, cooling and condensing the yielded gas, and performing titration of the absorbed liquid. CONSTITUTION:A sample of 1g is put on a porcelain board. Soda lime of 1g and the mixed agent of 0.5g of Al2O3+Fe2O3.H2O are added and mixed. The surface is evenly coated by 1g of said mixed agent. The surface is further coated by 1g of quartz cotton. The porcelain board is mounted on a quartz board. The board is inserted to a position of a pre-heater furnace 1 of a quartz reacting tube 3, whose temperature is kept at 430+ or -20 deg.C. He or Ar gas accompanying steam is introduced. After the heating for 10min, the board is moved into a decomposing furnace 2, which is kept at 1,000 deg.C. Complete decomposition is performed by heating. The decomposed gas is introduced into alkali bath in a steam storing mechanism 4. Ammonia component and steam are cooled and condensed by a condenser 8 and absorbed into an absorbing liquid. Then the ammonia component is determined. Thus nitrogen in coal can be efficiently analyzed in a stable state.

Description

[Detailed Description of the Invention] ``Object of the Invention'' The present invention relates to a method for analyzing nitrogen in coal. First, we aim to provide a method that can perform appropriate analysis without using harmful substances.

Industrial applications Coal nitrogen analysis technology.

Conventional technology JI is a method for analyzing nitrogen in coal and coke.
SM8813 stipulates the Kjeldahl process, semi-micro Kjeldahl process or semi-micro gasification process. That is, in the Kelsol method, mercury or mercuric oxide is added to concentrated sulfuric acid, and in the semi-microscopic and Rudahl methods, a mixture of mercuric sulfate and selenium powder is added as a dividing agent to concentrated sulfuric acid. In addition, in the semi-micro gasification method, as shown in Figs. 3 and 4, as shown in Fig. 3, sample 0.IP and 1 ton of soda lime powder are thoroughly mixed in magnetic, l = "-) 11. The reactor tube 12 is heated to 950 to 1000°C in the heating furnace 20.
A steam distillation mechanism 13 is connected to one inlet of the reaction tube 12 to introduce steam at a rate of 2 to 3 tt per minute for about 25 minutes, and the decomposed ammonia is transferred to the reaction tube 12. 2NH,S with two containers 14 connected in succession to the other ↓ mouth
Absorb in O4 solution. This absorbed liquid is transferred to the distillation flask 15 of the steam distillation apparatus shown separately in FIG. into a container 19 connected below the cooler 18, i.e., the boric acid saturated solution 2 in the container 19.
- to absorb the ammonia-containing water vapor, and use this as a mixed indicator of methyl red and methylene blue,
The ammonia content is determined by titration with a N/100 H2S 04 standard solution, with the end point at which the color changes from green to almost colorless (plI 5.4).

However, in this semi-micro gasification method, the wet decomposition operation can be carried out for 10 samples at a time, and there is a device that can recover the cyanmonium content by steam distillation in a short time from the ammonia-containing decomposition liquid produced by the wet decomposition. being developed.

Furthermore, in the Journal of the Japan Fuel Road Association, Q 377 (1980) and Analytical Chemistry 30.290' (1981), Akira Nomura et al. reported that they succeeded in analyzing nitrogen in coal, heavy oil, etc. using the sigasification method. The method is to add soda lime powder to the sample, mix it, coat it with a layered mixture of alumina (90A) and ferric chloride, and immediately apply 90A powder to the sample.
It is charged into a high temperature section of 0 to 1000℃ and thermally decomposed under the introduction of steam to generate ammonia, which is absorbed and collected in a dilute sulfuric acid solution, and then the ammonia in the absorption liquid is recovered by steam distillation. Then, titrate with N/100 H and SO.
(Determine @.Alternatively, the gas generated when water vapor is introduced is passed through a soda lime scrubber to remove Hα, and then N
This method collects and analyzes H.

Problems to be Solved by the Invention However, as mentioned above, the method specified in JIS M8813 uses harmful substances such as mercury, mercuric oxide, mercuric sulfate, and selenium powder, so post-treatment is required. When analyzing nitrogen in coke using the iO or semi-micro oxidation method, which is not a desirable method due to pollution problems, some of the alkali content spills out during operation and causes vitrification of the quartz reaction tube. , '#L times of use results in breakage, resulting in high material costs. In addition, this semi-micro gasification method requires a long time for analysis due to the multi-stage process, and it cannot be applied to nitrogen analysis of coal and heavy oil.This is due to the high temperature heating of the sample. This is because the body is distracted without reacting.

Furthermore, the method by Mr. Nomura et al. requires the removal of hydrogen chloride gas generated by thermal decomposition of ferric chloride under the introduction of steam, and also requires the removal of hydrogen chloride gas and the generation of ammonium chloride fume with hydrogen chloride and ammonia. In the following case, there is a risk that the ammonia content will not be absorbed by the absorption liquid, and that the ammonia content will be oxidized when Fhx04 is produced by thermal decomposition of ferric chloride (FhCl) under the introduction of steam.

"Structure of the Invention" Means for Solving the Problems The present invention was developed after consideration to solve the problems of the conventional products as described above. After adding and mixing a predetermined amount of a mixture of soda lime, alumina, and hydrated iron oxide, the above-mentioned ? −
The boat was maintained at 430 ± 20°C and charged into a nine reaction tube, heated in an inert gas atmosphere containing water vapor for a predetermined time, and then the boat in the reaction tube was maintained at 950 to 1000°C. NH generated by heating for a predetermined period of time.

This coal nitrogen analysis method is characterized in that gas is absorbed into an absorption liquid via a steam distillation mechanism connected to the reaction tube, and the ammonia content is determined quantitatively.

A predetermined amount of a mixture of soda lime, alumina, and hydrated iron oxide is added to a working coal sample, mixed, and heated at 430±20°C for a certain period of time to cause a decomposition reaction of volatile components and generate ammonia. be able to. The sample is then transferred to a reactive decomposition atmosphere maintained at 950 to 1000° C. - The sample is completely decomposed. The gas obtained by these thermal decomposition reactions is cooled, condensed, and absorbed into an absorption liquid, and the amount of N can be determined by titrating the absorption liquid.

EXAMPLE To explain the method according to the present invention in comparison with the method according to the JIS method described above, the above-mentioned disadvantages in the gasification method according to the JIS method shown in FIGS. 3 and 4 and the problems presented by Mr. Nomura et al. In order to solve this problem, the present inventors conducted an advantageous analysis using an apparatus as shown in FIG.

That is, in this apparatus, a quartz reaction tube 3 is inserted into a preheating furnace 1 and a reaction decomposition furnace 2, and a steam distillation mechanism 4 is connected to the outlet side (left side in the figure) of the reaction tube 3. The distillation flask 41 in the distillation mechanism 4 contains a concentrated caustic soda solution, and the outside of the flask 41 is heated in an oil bath (polyethylene glycol 400 or 600) 42, and when the caustic soda concentration is 40%, the temperature is 135°C and 20%. So 13
By keeping the temperature of each oil bath 42 constant at 0° C., the concentration of the caustic soda solution can be maintained at a constant level without increasing or decreasing the volume.

From the inlet of the reaction tube 3 (on the right side in the figure), a gas vapor distillation mechanism 5 containing water vapor, such as He or Ar, is introduced.
If this method of introducing He or Ar gas is adopted, two processes will occur: one is the decomposition process of the sample, and the other is the steam distillation of the ammonia in the absorption liquid, as in the conventional method shown in Figures 3 and 4. This is because the present invention requires a pressure above a certain level for the introduced gas in order to perform heat treatment decomposition of the sample and recovery of the ammonia component by steam distillation in one step, rather than a step process.

For this purpose, as shown in FIG.
If He gas (100-/-) is introduced into hot water maintained at a temperature of 0.degree. C. and water vapor is entrained, it is possible to introduce 2 to 3 C. water vapor as the moisture content specified by the JIS method.

Regarding this part, as shown in Fig. 2 separately, water is pumped into the reaction quartz tube 3 using a roller pump (tubing pump) 6.
The quartz tube at the introduction point is heated to approximately 200°C by the heater 7 to generate water vapor, and the water vapor generated by the He or Ar gas introduced from the inlet at the same time is entrained. Good too.

Water may be supplied into the quartz tube 3 by the roller pump 6 through a supply pipe attached to the quartz tube itself, or through a stainless steel pipe (from the supply port of the adapter as shown by the dotted line in FIG. 2). Also, in the case of roller pumps, it is easy to keep the water supply constant by adjustment.

Although FIG. 1 shows the case where there is only one reaction quartz tube 3, if a furnace with two or more reaction quartz tubes 3 is used, the N/N/N ratio will be reduced in the sample thermal decomposition process. 1001i
Since the titration can be completed at t S 04, the analysis time can be reduced by half or more.

To explain the analysis operation using the above-mentioned apparatus, 0.1r of sample is weighed into a porcelain boat 11, and powdered soda lime 12 and powdered (AltOa + Ftb@O@・
H! O) Mixture α5f is added and mixed, and the mixture 1t is evenly layered and coated thereon. This coating layer is further coated with about 19 quartz wool to prepare.

This porcelain boat 11 was further placed on a quartz boat and placed in the preheating furnace 1 maintained at 430±20°C in the quartz reaction tube 3 shown in FIG.
) is introduced into He or Ar gas (100v/(). After heating for 10 minutes in the preheating furnace 1,
The boat was moved to a position in the reaction decomposition furnace 2 maintained at 000° C., and heated there for 20 minutes to completely decompose it. The introduced He or Ar gas containing ammonia generated by the thermal decomposition in the preheating furnace 1 and the reaction decomposition furnace 2 is introduced into the alkaline bath of the steam distillation mechanism 4, where the hydrogen sulfide generated by the thermal decomposition of the sample is removed. After cooling and condensing the ammonia and water vapor in Conte-8, 2 g of saturated boric acid solution was added.
/100 H2SO4 is absorbed by a certain amount of absorption liquid. After adding a certain amount of N/100 NH4OH solution to the collected absorption liquid to increase the pH value, using a pIistat, dropwise add N/100 HeSO4 and titrate to pH5.41. Find 9.

However, in the above formula, f: coefficient of N/100H2SO4, xl: titration N/
100 He So, ml, x2 = Added N/100
H, So, m, χ,: Added N/100 NH4O
H-equivalent N/100 H snow So, ag, b blank value-number, W: sample number.

To explain the analysis operation using the above-mentioned apparatus, in the present invention, alumina and hydrated iron oxide (r
-Tight) is used.

An example of this mixture is hydrated iron oxide (Fiz 0B/H,
0) 10g and alumina (90A pore) 150?
The mixture is prepared by mixing the ingredients, but the mixing ratio may be changed as appropriate.

Said hydrated iron oxide < 2 FaOOH= Ft203・H
2O) is thermally decomposed to generate H,0 min, which contributes to the thermal decomposition reaction in the presence of an alkali. Also H2O
The glue after it comes off is 0. Because crystals produce lattice defects,
It can be expected to generate activity and have a catalytic effect. Shirho
Therefore, it is not possible to expect the effect seen in the rapid reaction between hα,+H,0 and volatile matter in the coal due to thermal decomposition, so the coal sample is confined under certain heating conditions and the reaction is carried out. It is necessary to do so. As mentioned in the analysis procedure above, the conditions are as follows: sample 0.19 and powdered soda lime 1
t, Oyo U (AltOn +F4*Os ”He
O) Thoroughly mix 0.5 t of the mixture, further coat the mixture by uniformly layering it with the powder 12 of the mixture described above, and further cover with about 0.12 t of quartz wool. For example, 430±2 while introducing He or Ar gas accompanied by water vapor.
Heating at 0°C for 10 minutes is suitable.

After completing the thermal decomposition of quartz volatile matter, soda lime, and water vapor under these conditions, &-to 11 was heated to 100%.
Transfer to a location at 0°C to complete thermal decomposition of the remaining coal. In the present invention, since the range of the preheating temperature is as narrow as 430±20°C, it is difficult to use the radiant heat from the reaction and decomposition furnace 2, for example, in terms of temperature distribution. is an unreliable element.

Furthermore, in the present invention, as mentioned above, we adopted a method in which water vapor is entrained in He or Ar gas, but this method involves blowing the ammonia generated by thermal decomposition of the sample into the alkaline bath of the connected Kurobe apparatus, and then steam distillation. In order to be able to
This cannot be passed because it is necessary to apply a certain amount of pressure.

In addition, in the analysis method of the present invention, in addition to 2 tat of a boric acid saturated solution specified by the JIS method, a certain amount (for example, 10 d) of N/100 H, So solution is added to the absorption liquid. This is different from the case of steam distillation according to the JIS method.
Or the Ar gas passes through the high temperature zone and the ammonia content is not completely collected, or the ammonia content increases as the pH value of the absorption liquid increases. This is because there is a possibility that some of the ammonia content may be lost, so as mentioned above, add a certain amount (for example, 10 m) of N/100 mountain S04 solution to the boric acid saturated solution 2- to adjust the pH after collecting the ammonia content.
The value should be 4 or less so that there is almost no NH, partial pressure in the solution after absorption. Furthermore, N/100 before titration
The method is to increase the pH value of the solution by adding, for example, 5 TRt of NH4OH solution, and then titrate using a pflstat to 4 ps by the differential method.

A specific analysis example according to the present invention will be explained as follows.

Analysis Example 1 A flat sample of bituminous coal with a volatile content of 33% [brand Remington (water content: 25% a): IO, 0812f was accurately weighed into a porcelain container, and powdered soda was added to it. 1 ton of lime and powdered (#, O, + V, C), H, 0) mixture 0.
Add 51 and mix well, then add this mixture 1?
Laminate and cover uniformly using

This coating layer is further coated with about 0.12 quartz wool.

This porcelain boat was further placed on a quartz boat, and the preheating furnace 1 was maintained at 430±20°C in the quartz reaction tube shown in Figure 1.
It is charged at the position of
/―, ) will be introduced. After heating in the preheating furnace 1 for 10 minutes, the shade is transferred to a position in the furnace 2 maintained at 1000° C. and heated there for 20 minutes to completely decompose it.

The introduced He gas containing ammonia generated by the accelerated decomposition in the preheating furnace 1 and the reaction decomposition furnace 2 is introduced into the alkaline bath of the steam distillation apparatus, where the hydrogen sulfide generated by the thermal decomposition of the sample is removed. Ammonia and water vapor are cooled and condensed in a condenser (boric acid saturated liquid 2 m −)
-N/100H! 80.10 tri ) of absorbent solution, and the beaker containing the absorbent solution was removed. After absorption, the pH value of the absorption liquid was 3.85 and dust was added to it.
100NH40H5m (N/100H, So,
4.95m equivalent), the pH value was 7.43.
rose to N/100 H,S using p■stat
Titrate using the differential method to pH 5.4 with O, titration amount is 3.6
Got 4-. From this, the N analysis value was calculated as follows.

α812 The following table summarizes the results of similar analysis of the other four brands (Cero, Canmore, Hongui, and Coke).

Note: Analysis example 2 using the semi-micro Kelbour method for coal and the gasification method for coke. Coke sample (moisture content; 1.21%) 0.1021
? was weighed out in a porcelain hoard, 1 ton of powdered soda lime was added thereto, mixed, and then covered with about 0.1 f of quartz wool. This boat was further placed on a quartz cart, charged into a quartz reaction tube, placed in the reaction cracking furnace 2 maintained at 1000°C as shown in Fig. 1, and placed in the reaction tube with water vapor (
Heif gas containing 2 to 3 w4t/sm) was introduced and thermally decomposed for about 20 minutes, and the generated ammonia was absorbed into the absorption liquid.

The absorption liquid was prepared at N/100 using the same analytical procedure as the following analysis.
It was titrated with Ha S 04 to obtain a titer of L82m.

From this result, N: 0.92% was obtained by the following calculation.
-, but this was consistent with the analytical value of the conventional method (gasification method).

0.1021 100-1.21 "Effect of the invention" When the present invention as explained above is applied, JISM881
It is possible to analyze nitrogen in coal in a stable state using the gasification method, which could not be analyzed using the gasification method described in 3.
In addition, it is efficient because it can be analyzed in a single process in a single device, and it is possible to connect multiple gas reaction tubes as appropriate, further doubling the efficiency. This invention can be carried out without using prefectural substances, and has the effect of preventing damage to the quartz tube and enabling long-term analytical operations, making it an industrially highly effective invention.

[Brief explanation of the drawing]

The drawings show the technical contents of the present invention, and FIG. 1 is a conceptual diagram showing an outline of the apparatus for carrying out the method of the present invention, FIG. 2 is an explanatory diagram of the steam distillation mechanism, and FIG. FIG. 3 is an explanatory diagram of a conventional gasifier according to JIS M8813, and FIG. 4 is an explanatory diagram of the same conventional steam source reservoir according to the semi-micro Kermer process. In these drawings, 1 is a preheating furnace, 2 is a reaction cracking furnace, 3 is a quartz reaction tube, 4 is a steam distillation mechanism, 5 is a steam distillation mechanism, 6f'i is a low pump or tubing pump, 7 is a heater, 11 indicates a porcelain boat.

Claims (1)

[Claims] Weighing a predetermined amount of coal sample into a boat, adding and mixing a predetermined amount of a mixture of soda lime, alumina, and hydrated iron oxide, and then charging the boat into a reaction tube maintained at 430 ± 20 ° C., Heating in an inert gas atmosphere containing water vapor for a predetermined period of time, and then heating the boat in the reaction tube at a temperature of 950 to 100
The generated N
A coal nitrogen analysis method, characterized in that H_3 gas is absorbed into an absorption liquid via a steam distillation mechanism connected to the reaction tube, and the ammonia content is determined.