Combustion pyrolysis device for organic sample

Abstract

The utility model discloses a combustion pyrolysis device for organic samples, which comprises a ball valve sample injector, a gas inlet unit and a combustion unit, the combustion unit comprises a combustion tube, a crucible and a hearth, the crucible is fixed in the combustion tube, the combustion tube extends into the hearth for heating, and the ball valve sample injector is communicated with the combustion tube; the gas inlet unit comprises an oxygen lance assembly and a buffer assembly, the oxygen lance assembly extends into the surface of an organic sample at the bottom of the crucible, and the buffer assembly comprises a three-way electromagnetic valve, a buffer pipe, a gas carrying pipe and a gas outlet pipe; and an outlet of the three-way electromagnetic valve is selectively communicated with a carrier gas pipe to introduce carrier gas or is communicated with a gas outlet pipe to exhaust gas. The device solves the technical problem that in the prior art, oxygen supply parameters are complex in design when different coal samples are combusted and pyrolyzed.

Description

Technical Field

[0001] The present application relates to the technical field of combustion pyrolysis, and particularly to a combustion pyrolysis device for organic samples. Background Art

[0002] The quantitative oxygen supply combustion pyrolysis technology is widely used in organic elemental analyzers for chromatographic separation or adsorption separation. The characteristics of this technology are as follows: an organic sample burns by injecting oxygen in the carrier gas flow of a high-temperature combustion tube, and its target elements carbon, hydrogen, nitrogen, and sulfur are oxidized into primary products in the combustion tube, and then are converted into target gases carbon dioxide, water, nitrogen, and sulfur dioxide in a reduction tube, and then pass through a purification system and a separation system and are introduced into a thermal conductivity detector for analysis.

[0003] In the prior art, the combustion pyrolysis of organic samples mainly undergoes two stages: gas-phase combustion mainly based on volatile matter and solid-phase combustion mainly based on combustible solids; during the combustion pyrolysis process of organic samples, corresponding combustion time and oxygen flow rate need to be configured for these two stages respectively. For difficult-to-burn organic samples such as coal samples, bituminous coal is easy to burn, with a large initial concentration gradient and intense gas-phase combustion; anthracite has a slow combustion rate and a long duration of solid-phase combustion. Therefore, the design of oxygen supply parameters is relatively complex for different coal samples. Utility Model Content

[0004] The present utility model provides a combustion pyrolysis device for organic samples to solve the technical problem of complex design of oxygen supply parameters during the combustion pyrolysis of different coal samples in the prior art.

[0005] To achieve the above object, the technical solution provided by the present utility model is as follows:

[0006] The present utility model provides a combustion pyrolysis device for organic samples, including a ball valve injector, an air inlet unit, and a combustion unit. The combustion unit includes a combustion tube, a crucible, and a furnace chamber. The crucible is fixed inside the combustion tube, and the combustion tube extends into the furnace chamber for heating. The ball valve injector is communicated with the combustion tube. The air inlet unit includes an oxygen gun assembly and a buffer assembly. The oxygen gun assembly extends to the surface of the organic sample at the bottom of the crucible. The buffer assembly includes a three-way solenoid valve, a buffer tube, a carrier gas pipe, and an exhaust pipe. One end of the buffer tube is communicated with the combustion tube, and the other end is communicated with the inlet of the three-way solenoid valve. The outlet of the three-way solenoid valve is selectively communicated with the carrier gas pipe to introduce carrier gas or communicated with the exhaust pipe to exhaust gas.

[0007] Further, the length of the buffer tube is 20m - 50m.

[0008] Further, the distance between the end of the oxygen gun assembly and the surface of the organic sample is 5mm - 40mm.

[0009] Further, the combustion and pyrolysis device further includes a flow limiting valve, and the flow limiting valve is installed on the air outlet pipe.

[0010] Further, the air inlet unit is provided with a purge gas inlet, and the purge gas inlet is connected to purge gas and communicates with the combustion tube.

[0011] The combustion and pyrolysis device for organic samples provided by the utility model can enable the gas-phase combustion and solid-phase combustion of the organic samples to be carried out simultaneously by arranging an oxygen lance assembly to extend to the surface of the organic samples at the bottom of the crucible, reduces the oxygen flow rate, and does not require changing the oxygen flow rate midway. Therefore, there is no need to design complex oxygen supply parameters, reducing the process difficulty; by arranging buffer components such as a buffer tube and a three-way solenoid valve, the mixed gas generated by combustion can enter the buffer tube along with the excess oxygen for premixing. After the primary combustion in the combustion tube ends, the carrier gas loads the excess oxygen and the mixed gas in the buffer tube into the combustion tube for secondary combustion, improving the combustion efficiency. Description of the Drawings

[0012] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments recorded in the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0013] Figure 1 It is a schematic structural diagram of the combustion and pyrolysis device for organic samples in the embodiment of the utility model;

[0014] Figure 2 It is another schematic structural diagram of the combustion and pyrolysis device for organic samples in the embodiment of the utility model;

[0015] Figure 3 It is a TCD curve graph of the combustion and pyrolysis of organic samples in the embodiment of the utility model.

[0016] Reference Signs:

[0017] 10, ball valve injector; 21, combustion tube; 22, crucible; 23, furnace; 31, oxygen lance assembly; 321, three-way solenoid valve; 322, buffer tube; 323, carrier gas pipe; 33, purge gas inlet. Detailed Embodiments

[0018] In order to enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of this application, rather than all the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of this application.

[0019] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly disposed on the other element; when an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0020] It should be understood that the orientation or positional relationship indicated by terms such as "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing this application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to this application.

[0021] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of this application, the meaning of "a plurality of" and "several" is two or more, unless otherwise specifically defined.

[0022] It should be noted that the structures, proportions, sizes, etc. shown in the drawings of this specification are only used to cooperate with the content disclosed in the specification for those who are familiar with this technology to understand and read, and are not used to limit the conditions under which this application can be implemented. Therefore, they do not have a substantial technical meaning. Any modification of the structure, change in the proportional relationship, or adjustment of the size, without affecting the effects that this application can produce and the purposes that can be achieved, should still fall within the scope covered by the technical content disclosed in this application.

[0023] Such as Figure 1 、 Figure 2As shown in the figure, an embodiment of the present application provides a combustion pyrolysis device for organic samples, which includes a ball valve sampler 10, an air inlet unit, and a combustion unit. The combustion unit includes a combustion tube 21, a crucible 22, and a furnace chamber 23. The crucible 22 is fixed inside the combustion tube 21, and the combustion tube 21 extends into the furnace chamber 23 for heating. The ball valve sampler 10 is communicated with the combustion tube 21. The air inlet unit includes an oxygen lance assembly 31 and a buffer assembly. The oxygen lance assembly 31 extends to the surface of the organic sample at the bottom of the crucible 22. The buffer assembly includes a three-way solenoid valve 321, a buffer tube 322, a carrier gas tube 323, and an outlet tube. One end of the buffer tube 322 is communicated with the combustion tube 21, and the other end is communicated with the inlet of the three-way solenoid valve 321. The outlet of the three-way solenoid valve 321 is selectively communicated with the carrier gas tube 323 to introduce carrier gas or communicated with the outlet tube to exhaust gas.

[0024] In the embodiment of the present application, referring to Figure 1 , the organic sample is purged in the ball valve sampler 10 and then put into the ash crucible 22 of the combustion tube 21. Before putting in the organic sample, carrier gas is first introduced into the entire gas path; after putting in the organic sample, oxygen is introduced into the combustion tube 21 while the carrier gas is cut off. The furnace chamber 23 is heated to 1140°C to 1160°C, and the organic sample burns in oxygen. The formed residue is collected in the ash crucible 22, and a part of the mixed gas generated by the reaction enters the subsequent gas path for purification, separation, and detection, and the other part is carried into the buffer tube 322 by excess oxygen. The bottom of the crucible 22 is breathable to facilitate the rapid passage of gas.

[0025] Referring to Figure 2 , one end of the buffer tube 322 is communicated with the combustion tube 21, and one end is communicated with the three-way solenoid valve 321. Before the organic sample starts to burn, the three-way solenoid valve 321 is communicated with the carrier gas tube 323 to fill the entire gas path with carrier gas; then when oxygen is introduced into the combustion tube 21, the three-way solenoid valve 321 is communicated with the outlet tube, the carrier gas is cut off, and the carrier gas is slowly discharged into the air from the outlet tube; the furnace chamber 23 is heated, and the organic sample burns in the combustion tube 21. The generated mixed gas is premixed with the excess oxygen and enters the buffer tube 322. At the same time, due to the pressure drop in the combustion tube 21, oxygen is more likely to be ejected to the surface of the organic sample, and a fluidization reaction occurs with the organic sample. Moreover, the contact area between oxygen and the organic sample increases, which can improve the rate of the solid-phase reaction. The consumption of oxygen is preset. After the preset amount of oxygen is introduced, the three-way solenoid valve 321 is communicated with the carrier gas tube 323 again, and carrier gas is introduced to transport the oxygen and the mixed gas in the buffer tube 322 into the combustion tube 21 together. The temperature of the furnace chamber 23 is set to 1140°C to 1160°C for secondary combustion.

[0026] In the organic sample combustion and pyrolysis device according to the embodiments of the present application, by arranging the oxygen lance assembly 31 to extend to the surface of the organic sample at the bottom of the crucible 22, the gas-phase combustion and solid-phase combustion of the organic sample can be carried out simultaneously, reducing the oxygen flow rate and eliminating the need to change the oxygen flow rate midway. Therefore, there is no need to design complex oxygen supply parameters, reducing the process difficulty. By arranging buffer components such as the buffer tube 322 and the three-way solenoid valve 321, the mixed gas generated by combustion can enter the buffer tube 322 along with the excess oxygen for premixing. After the primary combustion in the combustion tube 21 is completed, the carrier gas is used to introduce the excess oxygen and the mixed gas in the buffer tube 322 into the combustion tube 21 for secondary combustion, improving the combustion efficiency.

[0027] In some embodiments, the combustion and pyrolysis device further includes a flow limiting valve, and the flow limiting valve is installed on the outlet pipe. In the embodiments of the present application, when the three-way solenoid valve 321 is communicated with the outlet pipe, the carrier gas is cut off, and the carrier gas in the buffer tube 322 is discharged to the air through the outlet pipe. The flow limiting valve is installed on the outlet pipe to control the discharge speed of the carrier gas.

[0028] In some embodiments, the intake unit is provided with a purge gas inlet 33, and the purge gas inlet 33 is connected to the purge gas and communicated with the combustion tube 21. On the one hand, the purge gas can purge the organic sample in the sample inlet ball valve, and on the other hand, the purge gas can purge the entire gas path to keep the instrument detector connected to the analysis gas path in a balanced state.

[0029] The above-mentioned method for combustion and pyrolysis of organic samples includes the following steps: S1. Introduce the carrier gas to be transmitted through the buffer tube 322 into the combustion tube 21 and enter the analysis gas path;

[0030] S2. Add the organic sample into the combustion tube 21, introduce oxygen to the surface of the organic sample in the combustion tube 21, heat and burn, and the oxygen flow rate is 85-95 mL / min; at the same time, cut off the carrier gas and discharge the carrier gas in the buffer tube 322 to the air, and the excess oxygen and the mixed gas after combustion and pyrolysis enter the buffer tube 322;

[0031] S3. Open the carrier gas and introduce it into the buffer tube 322, and the carrier gas loads the excess oxygen and the mixed gas into the combustion tube 21 for secondary combustion, and the gas after secondary combustion enters the analysis gas path.

[0032] In the combustion pyrolysis method of the organic sample according to the embodiment of the present application, oxygen is introduced onto the surface of the organic sample in the combustion tube 21, and a certain oxygen flow rate is maintained unchanged, so that gas-phase combustion and solid-phase combustion proceed simultaneously without the need to change the oxygen flow rate midway. Therefore, there is no need to design complex oxygen supply parameters, reducing the process difficulty. At the same time as oxygen is introduced, the carrier gas is cut off, so that the excessive oxygen and the mixed gas generated by the reaction enter the buffer tube 322. At this time, the pressure in the combustion tube 21 drops, which is more conducive to oxygen reaching the surface of the organic sample and undergoing fluidized combustion with the organic sample. Moreover, the contact area between oxygen and the sample increases, improving the speed of the solid-phase reaction. After the primary combustion is completed, the carrier gas is opened to introduce the oxygen and the mixed gas in the buffer tube 322 into the combustion tube 21 for secondary combustion. At this time, no system oxygen supply is required. Since the oxygen and the mixed gas are premixed in the buffer tube 322, the efficiency of the secondary combustion is greatly improved.

[0033] In the embodiment of the present application, the carrier gas is high-purity helium. First, the carrier gas is introduced to pass through the buffer tube 322, then enter the combustion tube 21, and finally enter the analysis gas path. The analysis gas path uses the adsorption separation method to separate the mixed gas one by one, and finally introduces it into the thermal conductivity detector for separate quantification, and uses a 5E-CHONS2400 organic element analyzer for analysis. Further, it is purged into the analysis gas path through the purge gas path to make the instrument detector in a balanced state. No combustion occurs during this process, and its function is to wait for the baseline of the instrument detector to be stable.

[0034] In step S2, after adding the organic sample into the combustion tube 21, oxygen is started to be introduced. One end of the oxygen gun assembly 31 is close to the organic sample to facilitate directly delivering oxygen to the surface of the organic sample and heating it for combustion. Specifically, in step S2, oxygen is introduced onto the surface of the organic sample, and the distance between the end of the oxygen gun assembly 31 and the surface of the organic sample is 5 mm to 40 mm. After repeated tests on different organic samples, the oxygen flow rate is controlled at 85 to 95 mL / min. Preferably, the oxygen flow rate introduced in step S2 is 90 mL / min. In this case, gas-phase combustion and solid-phase combustion proceed simultaneously. The combustion temperature in step S2 is set to 1140 °C to 1160 °C. In the embodiment of the present application, the organic sample is allowed to crack into combustion intermediate products such as alkanes and thiols. Therefore, the oxygen flow rate in the embodiment of the present application is greatly reduced compared with the oxygen flow rate in the prior art (generally 150 mL / min).

[0035] In the embodiment of the present application, the carrier gas is cut off while oxygen is introduced, so that the carrier gas filled in the buffer tube 322 begins to slowly leak into the air, and the mixed gas produced by combustion enters the buffer tube 322 with the excess oxygen, so that the pressure in the combustion tube 21 decreases. At this time, the oxygen of the oxygen gun assembly 31 is more easily sprayed to the combustion surface, and fluidized combustion occurs with the powder of the organic sample, and the contact area between oxygen and the organic sample is increased, thereby increasing the speed of the solid phase reaction and reducing the oxygen consumption. Specifically, the length of the buffer tube 322 is 20m to 50m.

[0036] Further, the total amount of oxygen introduced in step S2 is the oxygen consumption when the organic sample is completely burned. The oxygen consumption when the organic sample is completely burned is the maximum oxygen consumption during combustion to ensure the smooth completion of gas phase combustion and solid phase combustion. In other words, the total amount of oxygen that needs to be introduced is calculated based on the oxygen consumption when the total carbon content in the organic sample is completely burned, which is the oxygen introduction amount preset according to the organic sample.

[0037] Furthermore, in step S2, before the organic sample is added to the combustion tube 21, the organic sample is purged through the purge gas path to ensure that there are no impurities remaining in the gas path and to allow the TCD to establish a stable baseline voltage to prepare for subsequent measurements.

[0038] In an embodiment of the present application, after the preset oxygen intake reaches the requirement, the system no longer needs to continue to supply oxygen. In step S3, the carrier gas is turned on, and the carrier gas is introduced into the buffer tube 322 again. At this time, the carrier gas carries the excess oxygen and mixed gas in the buffer tube 322 into the combustion tube 21 for secondary combustion. Since the mixed gas and oxygen have been mixed in the buffer tube 322 in advance before the secondary combustion, the full diffusion of the two can greatly improve the efficiency of the secondary combustion. The duration of the secondary combustion must ensure that the nitrogen peak in the TCD curve is complete. Specifically, the temperature of the secondary combustion is 1140℃~1160℃. Whether the reaction in the secondary combustion stage is sufficient depends on whether the detector baseline returns to zero normally. The return of the detector baseline to zero proves that no gas to be tested is generated in the instrument gas path and the combustion tube reacts completely, otherwise a gas peak should appear.

[0039] Specifically, a combustion pyrolysis method of an organic sample comprises the following steps:

[0040] 1. Before starting the test, the instrument first enters the conditioning stage, the two-position three-way valve is in the left position, the carrier gas (high-purity helium) enters the combustion tube through the buffer assembly until the subsequent analysis gas path, and the instrument detector is in a balanced state by purging the gas path. No combustion occurs during this process, just waiting for the instrument detector baseline to stabilize. The length of the buffer tube is 20m.

[0041] 2. Put 20 mg of coal sample A into the combustion tube. The oxygen gun assembly feeds oxygen into the combustion tube for 90 s, raises the temperature of the furnace chamber to 1150 °C, and makes coal sample A enter the combustion stage. The distance between the front end of the oxygen gun assembly and coal sample A is 5 mm. In this embodiment, according to the inner diameter of the oxygen gun barrel, the position where coal sample A falls into the combustion tube, the combustion temperature and pressure conditions, the oxygen is directly fed to the combustion surface of coal sample A. After repeated debugging of the test equipment, the oxygen flow rate is controlled at 90 mL / min. At this time, gas-phase combustion and solid-phase combustion occur simultaneously. Since coal sample A is allowed to crack into combustion intermediate products such as alkanes and mercaptans, the oxygen flow rate used in this embodiment is greatly reduced compared with the prior art (generally 150 mL / min). The total amount of oxygen fed into the combustion tube is calculated according to the amount of oxygen required for the complete combustion of coal sample A, that is, the total amount of oxygen fed is 100 mL.

[0042] 3. While feeding oxygen, the buffer assembly starts to work. The two-way three-way valve is in the right position, the carrier gas is cut off, and the high-purity helium gas filled in the buffer tube starts to slowly discharge into the air through the limit valve. The mixed gas generated by the above combustion enters the buffer tube for premixing with the excessive oxygen. At the same time, due to the pressure drop in the combustion tube after the combustion reaction, the oxygen output by the oxygen gun assembly is more likely to be sprayed onto the combustion surface of coal sample A, and fluidized combustion occurs with the powder sample. The contact area between oxygen and combustion increases, and the rate of the solid-phase reaction is improved. (To achieve the same effect, in the prior art, since the gas in this stage will be transported to the subsequent analysis gas path, the system pressure is relatively high, generally 0.22 MPa, and there is no secondary combustion. To ensure sufficient combustion and solid-phase combustion reaching the combustion surface, more oxygen flow rate is required.)

[0043] 4. After feeding the preset total amount of oxygen, the combustion tube enters the second combustion stage. In this combustion stage, no system oxygen supply is required. Only the two-way three-way valve needs to be reset to the left position, and carrier gas is fed into the pipeline. The flow rate of the carrier gas is 600 mL / min, and the carrier gas can load the premixed gas into the high-temperature combustion tube to achieve secondary combustion. The mixed gas generated in the first combustion stage and oxygen are premixed in the buffer tube in advance. The full diffusion of the two greatly improves the combustion efficiency. The duration of the secondary combustion should ensure that the nitrogen peak is detected completely in the subsequent analysis.

[0044] The premixed gas burns evenly. Compared with the prior art solution, the nitrogen concentration peak will not change with the burning speed of the sample, the peak shape is sharp, and the data processing is more accurate. Refer to Figure 3 , in the detection and analysis, the peaks appear in sequence as: N peak, C peak, H peak, and S peak. The peak shape of the N peak is significantly regular after adopting the new solution, which is beneficial to the peak picking calculation of low-nitrogen samples.

[0045] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present utility model. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present utility model. Therefore, the present utility model will not be limited to the embodiments shown herein, but rather to the broadest scope consistent with the principles and novel features disclosed herein.

Claims

1. A combustion pyrolysis device for organic samples, characterized in that: It includes a ball valve injector, an air intake unit and a combustion unit, wherein the combustion unit includes a combustion tube, a crucible and a furnace, wherein the crucible is fixed in the combustion tube, the combustion tube extends into the furnace for heating, and the ball valve injector is connected to the combustion tube; The air intake unit includes an oxygen gun assembly and a buffer assembly, the oxygen gun assembly extends into the surface of the organic sample at the bottom of the crucible, the buffer assembly includes a three-way solenoid valve, a buffer tube, a carrier gas tube, and an outlet pipe, one end of the buffer tube is connected to the combustion tube, and the other end is connected to the inlet of the three-way solenoid valve; the outlet of the three-way solenoid valve is selectively connected to the carrier gas tube to let in the carrier gas or connected to the outlet pipe to exhaust the gas.

2. The combustion pyrolysis device for organic samples according to claim 1, characterized in that: The length of the buffer tube is 20m to 50m.

3. The combustion pyrolysis device for organic samples according to claim 1, characterized in that: The distance between the end of the oxygen gun assembly and the surface of the organic sample is 5 mm to 40 mm.

4. The combustion pyrolysis device for organic samples according to any one of claims 1 to 3, characterized in that: The combustion pyrolysis device further comprises a flow limiting valve, which is installed on the gas outlet pipe.

5. The combustion pyrolysis device for organic samples according to any one of claims 1 to 3, characterized in that: The air intake unit is provided with a purge gas inlet, and the purge gas inlet is connected with the purge gas and communicates with the combustion tube.

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