CN112834386A

CN112834386A - Coal/biomass slag flowing viscosity detection device and detection method

Info

Publication number: CN112834386A
Application number: CN202110250170.5A
Authority: CN
Inventors: 代百乾; 吉恒松
Original assignee: Monash Science And Technology Research Institute Of Suzhou Industrial Park
Current assignee: Monash Science And Technology Research Institute Of Suzhou Industrial Park
Priority date: 2021-03-08
Filing date: 2021-03-08
Publication date: 2021-05-25

Abstract

The invention belongs to the technical field of coal chemical industry detection, and particularly relates to a device and a method for detecting the flow viscosity of coal/biomass molten slag. The detection device comprises a heater, a reaction tube and a sample placing component; the heater is arranged outside the reaction tube and provides heat for the reaction tube; the sample placing part comprises a heat-conducting container and an inclined plate, wherein the inclined plate is used for placing a sample to be detected, and the inclined plate is 25-90 degrees relative to the heat-conducting container. The detection method comprises the steps of firstly setting the temperature of a reaction tube to a preset temperature; then placing the sample for heating; simultaneously introducing 1-5% CO (N) by volume fraction₂As an equilibrating agent) at a flow rate of 1-2L/min. The device for detecting the flow viscosity of the coal/biomass molten slag has the advantages of simple structure, easy and quick detection method, detection data close to a theoretical value, wide application range and suitability for biomass ash and coal ash, and the ash amount can be detected only by 0.1-0.4 g.

Description

Coal/biomass slag flowing viscosity detection device and detection method

Technical Field

The invention belongs to the technical field of coal chemical industry detection, and particularly relates to a device and a method for detecting the flow viscosity of coal/biomass molten slag.

Background

The combustion and gasification of various solid fuels such as coal, biomass and the like are high-temperature processes, the generated slag flows to be in a molten state at high temperature, in the high-temperature process, the slag flows to be discharged from the bottom in a slag form, more than 80 percent of the slag flows to be free to flow at the melting temperature, slag discharge is smooth, and the corrosion of the slag flow to a furnace wall can be relieved. Viscosity plays a key guiding role in high-temperature processes such as thermal power plants, coal chemical industry, biomass utilization and the like, and the viscosity can influence the discharge of ash in a system, so that stable operation is kept. 25Pa.s is the upper limit of the free-flow slagging system.

The existing viscometer is mainly a cylinder viscometer, and has the disadvantages of large ash amount requirement (the ash amount is more than 100g), high energy consumption, high operation experience requirement, slow temperature rise and decrease and time consumption; the deposition, recrystallization, volatilization and the like of ash content affect the measurement precision, the error range reaches 1 order of magnitude, and low-grade coal and biomass ash are not suitable for the reasons of high alkali metal content, easy evaporation and recrystallization.

Disclosure of Invention

In view of this, the present invention aims to provide a coal/biomass slag flow viscosity detection device, which has a simple structure and is easy to operate.

The coal/biomass slag flowing viscosity detection device comprises a heater, a reaction tube and a sample placing part;

the heater is arranged outside the reaction tube and provides heat for the reaction tube;

the sample placement member includes a thermally conductive container and an inclined plate.

Preferably, the reaction tube has the dimensions of 80 mm outer diameter, 70 mm inner diameter and 1.2 m length.

Further, the heater is an electric heating furnace heated by a silicon carbide rod, is fixed outside the reaction tube by using a fixing device and can perform section heating. Preferably, the fixing means is a flange.

Further, the reaction tube and/or the heat-conductive container and/or the inclined plate are/is made of corundum.

Specifically, the corundum material is selected because the corundum material has the following advantages of (1) high temperature resistance and high purity; (2) smooth surface, porosity of 5-6.5%, compact surface, and surface density of f3.6g/cm³The error caused by the penetration of the slag can be effectively reduced; (3) the cost is low, which is close to the component of the actual hearth material (4).

Furthermore, the sample to be detected is placed on the inclined plate and is 25-90 degrees relative to the heat-conducting container.

Further, the coal/biomass slag flowing viscosity detection device also comprises a reaction gas supply device and a protective gas supply device; the reaction gas supply device and the protective gas supply device are connected with one end of the reactor.

Preferably, the reaction gas supply device and the shielding gas supply device are provided with gas flow meters or the gas supply device and the shielding gas supply device are provided with gas flow meters at the connecting sections of the reaction pipes.

Further, the reaction gas is CO in N with the volume fraction of 1-5 percent₂The protective gas is an inert gas, preferably 99.99% argon.

Further, the coal/biomass slag flow viscosity detection device further comprises a vacuum pumping device, the vacuum pump provides a micro negative pressure environment in the furnace, and preferably, the vacuum pumping device is a vacuum pump.

The invention aims to provide a detection method for detecting the flow viscosity of coal/biomass slag by using the coal/biomass slag flow viscosity detection device. The detection method is simple and easy to implement, and the detection result is accurate.

The detection method comprises the following steps: the detection method comprises the following steps: (1) setting the temperature of the reaction tube at 1100-1400 ℃; (2) placing 0.1-0.4g of sample to be detected on an inclined plate, forming a 25-90 degree angle with the heat-conducting container, and staying for 10-120min at the temperature of 1100-; meanwhile, reducing gas with the volume fraction of 1-5% CO in N2 is introduced, and the flow rate is kept at 1-2L/min.

Furthermore, in order to prevent the sudden thermal fracture of the steel and the plate, a gradual advancing temperature zone can be set, and a temperature zone of 600 +/-50 ℃, 1000 +/-50 ℃, 1200 +/-50 ℃ and 1400 +/-50 ℃ is set; (2) placing the sample to be detected on an inclined plate, forming an angle of 25-90 degrees with the heat-conducting container, staying for 1-3min at a temperature range of 600 +/-50 ℃, 1000 +/-50 ℃ and 1200 +/-50 ℃, and then staying for 10-120min at a temperature range of 1400 ℃; simultaneously introducing 1-5% CO in N by volume fraction₂The flow rate of the reducing gas of (4) is maintained at 1 to 2L/min.

Wherein N is₂Is a balancing agent.

Preferably, the sample to be detected is 0.2g and is made into a gray block with the specification of 10 plus or minus 0.5mm x width 10 plus or minus 0.5mm x thickness 2 plus or minus 0.5 mm.

Preferably, the 1100-1400 ℃ temperature region is 1400 ℃, the 1100-1400 ℃ temperature region retention time is 40min, and the reducing gas is CO in N with the volume fraction of 1 percent₂A gas.

Further, the sample to be detected is 0.1-0.4g, and a gray block with a specification of 10 + -0.5 mm x width 10 + -0.5 mm x thickness 2 + -0.5 mm is manufactured.

Further, the detection method further comprises: after the experiment, the sample is rapidly moved out to the cooling end of the furnace by a stainless steel handle, the atmosphere is switched to argon atmosphere, and the sample is blown and cooled at a large flow rate of about 10L/min. After about two minutes, the sample holder was removed from the furnace and quenched in dry ice.

Further, the detection method further comprises: after heating, measuring the slag flowing length, and calculating the slag flowing length according to the following formula:

lnμ＝3.282281cosβ-1.882827lnL′+7.397108，

wherein μ is a slag viscosity and β is an angle formed by the inclined plate and the thermally conductive vessel. The invention has the beneficial effects that:

the coal/biomass molten slag flow viscosity detection device provided by the invention is simple in structure, the detection method is easy and quick to operate, the difference between the detection data and the theoretical value is almost zero, the ash amount can be detected only by 0.2g, the application range is wide, and the device is suitable for biomass ash and coal ash.

Drawings

FIG. 1 is a schematic diagram of a coal/biomass slag flow viscosity detection device according to the present invention.

FIG. 2 is a diagram of a flowing slag material with the same ash sample and different qualities.

FIG. 3 is a graph of the flow length of slag versus mass for the same ash sample with different masses.

FIG. 4 is a physical diagram of the slag flow at different temperatures for different ash samples.

FIG. 5 is a graph of the flow length of slag versus temperature for different ash samples at different temperatures.

FIG. 6 is a physical diagram of the slag flow for different flow times for different ash samples.

FIG. 7 is a graph of the flow length of slag versus residence time for different flow times for different ash samples.

FIG. 8 is a diagram of a slag flow object with different ash samples and different inclination angles.

FIG. 9 is a graph showing the relationship between the flow length of molten slag and the inclination angle for different ash samples at different inclination angles.

FIG. 10 is a graph showing the relationship between the slag flow length, the inclination angle and the fluidity.

FIG. 11 shows the relationship between the natural logarithm of the slag flow length, the inclination angle and the viscosity.

FIG. 12 is a graph showing the relationship between the slag viscosity, the inclination angle and the slag flow length.

FIG. 13 is a graph of experimental values versus theoretical values for the present invention.

In fig. 1, 1 is an electric heating furnace, 2 is a flange, 3 is a corundum reaction tube, 4 is a gas flowmeter, 5 is a reaction gas cylinder, and 6 is a protective gas cylinder.

Detailed Description

The examples are given for the purpose of better illustration of the invention, but the invention is not limited to the examples. Therefore, those skilled in the art should make insubstantial modifications and adaptations to the embodiments of the present invention in light of the above teachings and remain within the scope of the invention.

The composition of the Ash samples Ash 1, Ash 2, Ash 3, Ash 4, Ash 5, Ash 6, Ash 7 in this example are as given in Table 1 below.

TABLE 1 composition Table of various ash samples and their viscosities

Note: the viscosity in table 1 is a literature reference and is the viscosity value measured using a conventional high temperature viscometer.

Example 1 coal/biomass slag flow viscosity detection device

Referring to fig. 1, in fig. 1, 1 is an electric heating furnace, 2 is a flange, 3 is a corundum reaction tube, 4 is a gas flowmeter, 5 is a reaction gas cylinder, and 6 is a protective gas cylinder. The embodiment provides a coal/biomass slag flowing viscosity detection device, which comprises a heater, a reaction tube and a sample placing part.

The heater is an electric heating furnace which is fixed around the reaction tube through a flange to heat the reaction tube; the electric heating furnace is heated by a silicon carbide rod, and the highest temperature can reach 1550 ℃.

Wherein, the reaction tube is made of corundum materials, and has the dimensions of 80 mm of outer diameter, 70 mm of inner diameter and 1.2 m of length.

The sample placing part comprises a crucible and a corundum plate, and the sample to be detected is placed on the corundum plate.

Wherein, a reaction gas supply device and a protective gas supply device are added at one end of the reaction tube, and a gas flowmeter is arranged between the reaction gas supply device and the protective gas supply device to control and record the flow rates of the reaction gas and the protective gas; and the other end of the reaction tube is provided with a vacuum pump of a vacuum pumping device for providing a micro negative pressure device in the reaction tube, and the reaction gas supply device and the protective gas supply device are both gas cylinders.

Example 2 verification of parameters

The experimental steps are as follows:

1) before the experiment, the furnace is preheated to the set temperature under the protection of inert atmosphere (99.99% argon). Accurately weighing the ash sample to be detected, compacting the ash sample into an ash block with the size of 10mm in length, 10mm in width, 10mm in thickness and 2mm in thickness at the length of 50mm, 20mm and 2mm, putting the prepared ash sample into a corundum crucible, and adjusting the contact position of a corundum plate and the crucible to achieve an inclination angle of 25-90 degrees.

2) And (4) placing the crucible loaded with the ash sample into a tray with a handle, and slowly pushing the crucible into a hearth constant-temperature area. The pushing step is divided into 3 stages, the ash sample is sent to a position with a temperature range of 600 ℃ and stays for 1 minute, then is pushed to 1000 ℃ and stays for one minute, and finally is pushed to a constant temperature range of 1100-1400 ℃. Simultaneously introducing 1-5% of CO in N₂The flow rate of the reducing gas of (2) is maintained at about 1-2L/min, and the residence time is 10-120 min.

3) After the experiment, the sample is rapidly moved out to the cooling end of the furnace by a stainless steel handle, the atmosphere is switched to argon atmosphere, and the sample is blown and cooled at a large flow rate of about 10L/min. After about two minutes, the sample holder was removed from the furnace and quenched in dry ice.

(1) Influence of sample quality

Weighing ash samples 0.1g, 0.2g, 0.25g, 0.3g, and 0.4g respectively, at a third stage temperature of 1400 deg.C, residence time of 40min, and reducing gas of 1% CO in N₂The gas flow is 1L/min, the inclination angle is 25 degrees, the experiment is carried out according to the experimental steps, the slag flowing conditions of different ash samples are shown in figure 2, and the mass relationship between the slag flowing length and the ash samples is shown in table 2.

TABLE 2 Mass relationship between slag flow length and ash sample

Sample Mass (g)	Slag flow length (mm/g)
		0.10031	30.2268
0.19989	55.74
		0.2489	74.33
0.3042	87.07953
		0.4012	90.33062

And (4) conclusion: the slag flow length is linear in the ash mass range 0.1-0.3g, as shown in FIG. 3.

(2) Influence of temperature

Weighing 0.2g of four Ash samples of Ash 1, Ash 2, Ash 3 and Ash 4, wherein the temperature in the third stage is respectively as follows:

Ash 1：1300℃、1350℃、1400℃；

Ash 2：RT、1100℃、1200℃、1250℃、1300℃、1350℃、1375℃、1400℃；

Ash 3：1300℃、1350℃、1400℃；

Ash 4：1300℃、1350℃、1400℃；

the residence time is 40min, the reducing gas is 1% CO in N2, the gas flow is 1L/min, the inclination angle is 25 degrees, the experiment is carried out according to the experimental steps, the flowing conditions of the slag of different ash samples are shown in figure 4, and the relationship between the flowing length of the slag and the temperature of the experiment is shown in table 3.

TABLE 3 slag flow Length and temperature dependence

And (4) conclusion: the reciprocal temperature is in a linear relationship with the natural logarithm of the slag flow length: 1/T Vs ln (slag flow length), as shown in FIG. 5. The temperature and the slag flow length conform to the Arrhenius-type equation.

(3) Influence of the residence time

Weighing 0.2g of Ash samples Ash 1 and Ash 2, wherein the temperature in the third stage is 1400 ℃, and the retention time is as follows: reducing gas is 1% CO in N for 10min, 20min, 30min and 40min₂The gas flow rates are all 1L/min, the inclination angles are all 25 degrees, the experiment is carried out according to the experimental steps, the slag flowing conditions of different ash samples are shown in figure 6, and the relationship between the slag flowing length and the experimental temperature is shown in table 4.

TABLE 4 relationship of slag flow length and experimental residence time

And (4) conclusion: the slag flow length is linear with residence time as shown in figure 7.

(4) Influence of the Angle of inclination

Weighing 0.2g of four Ash samples of Ash 1, Ash 2, Ash 3 and Ash 4, wherein the temperature in the third stage is as follows: the retention time is 40min at 1400 ℃, the reducing gases are 1% CO in N2, the gas flow is 1L/min, the inclination angles are 25 degrees, 45 degrees, 60 degrees and 90 degrees, the experiment is carried out according to the experimental steps, the flow conditions of the slag of different ash samples are shown in figure 8, and the relationship between the flow length of the slag and the temperature of the experiment is shown in table 5.

TABLE 5 relationship between slag flow length and inclination angle

And (4) conclusion: the cosine of the angle of inclination is proportional to the length of the slag flow, as shown in FIG. 9.

Example 3 slag flow length vs. viscosity relationship

Weighing 0.2g of four Ash samples of Ash 1, Ash 2, Ash 3 and Ash 4, wherein the temperature in the third stage is as follows: the retention time is 40min at 1400 ℃, and the reducing gas is 1 percent CO in N₂The gas flow rates are all 1L/min, the relationship between the slag flow length, the inclination angle and the fluidity obtained by the test and calculation is shown in the following table 6, and a curve chart is shown in fig. 10.

TABLE 6 relationship between the slag flow length, the slag inclination angle and the slag fluidity

Note: in Table 6, X represents fluidity (reciprocal of viscosity), and Y represents the slag flow lengths (mm/g) of four Ash samples of Ash 1, Ash 2, Ash 3, and Ash 4.

The relationship between the natural logarithm of the slag flow length, the inclination angle, and the natural logarithm of the viscosity calculated and converted from the fluidity is shown in table 7 below, and fig. 11 is shown.

TABLE 7 relationship between the natural logarithm of the slag flow length, the angle of inclination and the viscosity

Note: in Table 7, X represents the natural logarithm of the viscosity and Y represents the natural logarithm of the slag flow length (mm/g).

To obtain: the slag viscosity and the slag flow length follow a power function:

wherein, mu: viscosity, β: the inclination angle upsilonz is the flow speed of the slag in the vertical direction, p: density, n: flow characteristic index, δ: thickness of slag film.

Further, the graph is shown in fig. 12.

Thus, an empirical formula of slag viscosity, inclination angle and slag flow length is obtained:

lnμ＝Acosβ+BlnL′+C

lnμ＝3.282281cosβ-1.882827lnL′+7.397108

example 4 Experimental validation

According to the experimental procedures in example 1, 0.2g of four Ash samples of Ash 1, Ash 2, Ash 3 and Ash 4 are weighed, and the temperature in the third stage is: the retention time is 40min at 1400 ℃, and the reducing gas is 1 percent CO in N₂The gas flow rates are all 1L/min, and Ash 1 and Ash are obtained2. The viscosities of the four Ash samples Ash 3, Ash 4, as compared to the corresponding theoretical viscosity values, are shown in Table 8 below, and are plotted in FIG. 13.

TABLE 8 comparison of the viscosity of the different ash samples with the corresponding theoretical viscosity values

The viscosities measured by the conventional viscometer (cylinder viscometer) are shown in Table 9 below.

TABLE 9 measurement of different ash sample viscosities with the existing viscometer

Ash sample	Viscosity Pa.s
		Ash 1	1.01
Ash 1	4.96
		Ash 1	11.1
Ash 1	17.9

And (4) conclusion: the viscosity value measured by the experiment is almost the same as the theoretical value, and the viscosity value measured by the existing viscosity instrument is far from the theoretical value.

Finally, the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting, although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions may be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all of them should be covered in the claims of the present invention.

Claims

1. The coal/biomass slag flow viscosity detection device is characterized by comprising a heater, a reaction tube and a sample placing part; the heater is arranged outside the reaction tube and provides heat for the reaction tube; the sample placing component comprises a heat-conducting container and an inclined plate, wherein the inclined plate is used for placing a sample to be detected, and the angle between the inclined plate and the heat-conducting container is 25-90 degrees.

2. The coal/biomass slag flow viscosity detection device according to claim 1, wherein the reaction tube and/or the heat-conductive container and/or the inclined plate are/is made of corundum.

3. The coal/biomass slag flow viscosity detection device according to claim 1, further comprising a reaction gas supply device and a shielding gas supply device; the reaction gas supply device and the protective gas supply device are connected with one end of the reactor.

4. The coal/biomass slag flow viscosity detecting device according to claim 3, wherein the reaction gas supplying device and the shielding gas supplying device are provided with gas flow meters or the gas supplying device and the shielding gas supplying device are provided with gas flow meters at a connection section with the reaction pipe.

5. The coal/biomass slag flow viscosity detection device according to claim 1, wherein the heater is a section-heating electric heating furnace heated by a silicon carbide rod and fixed outside the reaction tube by using a fixing device.

6. The coal/biomass slag flow viscosity detection device according to claim 1, further comprising a vacuum pumping device.

7. The detection method for detecting the flow viscosity of the coal/biomass slag by the coal/biomass slag flow viscosity detection device as claimed in any one of claims 1 to 6, is characterized by comprising the following steps: (1) setting the temperature of the reaction tube at 1100-1400 ℃; (2) placing 0.1-0.4g of sample to be detected on an inclined plate, forming a 25-90 degree angle with the heat-conducting container, and staying for 10-120min at the temperature of 1100-; simultaneously introducing 1-5% CO in N by volume fraction₂The flow rate of the reducing gas of (4) is maintained at 1 to 2L/min.

8. The detection method according to claim 7, wherein the sample to be detected is 0.2g and is manufactured into a gray block having a specification of 10 ± 0.5mm x width 10 ± 0.5mm x thickness 2 ± 0.5 mm.

9. The detecting method as claimed in claim 7, wherein the 1100-1400 ℃ temperature region is 1400 ℃, the 1100-1400 ℃ temperature region has a retention time of 40min, and the reducing gas is CO in N with a volume fraction of 1%₂A gas.

10. The detection method according to claim 9, further comprising: after heating, measuring the slag flowing length, and calculating the slag flowing length according to the following formula:

lnμ＝3.282281cosβ-1.882827lnL′+7.397108，

wherein μ is a slag viscosity and β is an angle formed by the inclined plate and the thermally conductive vessel.