Device and method for testing combustion dynamics of petroleum coke POX ash

Abstract

The invention discloses a petroleum coke POX ash combustion dynamics testing device and a testing method. The testing device comprises a heating furnace and a fluidized bed reactor arranged in the heating furnace, a feed port and an exhaust port are formed in the top of the fluidized bed reactor, a gas inlet is formed in the bottom of the fluidized bed reactor, a three-way gas switching valve is arranged at the gas inlet of the fluidized bed reactor, and two inlets of the three-way gas switching valve are connected to an inert gas storage tank and a high-purity air storage tank respectively; temperature sensors are arranged in the heating furnace and the fluidized bed reactor, the temperature sensors of the heating furnace are arranged at the upper part, the middle part and the lower part of the heating furnace, and the temperature sensor in the fluidized bed reactor is arranged at the central position of the fluidized bed reactor. The testing device provided by the invention can smoothly realize the combustion dynamics test of the petroleum coke POX ash, obtains the combustion dynamics parameters of the petroleum coke POX ash, and provides theoretical guidance for parameter adjustment in the combustion process of the petroleum coke POX ash.

Description

Technical Field

[0001] The present invention relates to the technical field of combustion kinetics testing of petroleum coke POX slag, and particularly relates to a device and a method for testing the combustion kinetics of petroleum coke POX ash slag. Background Art

[0002] During the petroleum refining process, most of the heavy metals in crude oil are concentrated in petroleum coke, and then further concentrated in the hydrogen production ash slag of petroleum coke (i.e., POX ash slag) through the petroleum coke hydrogen production process. The petroleum coke POX ash slag containing heavy metals is a hazardous waste and needs to be properly disposed of. For petroleum coke POX ash slag, combustion is usually used for disposal. In order to better guide the combustion parameters of petroleum coke POX ash slag, the combustion kinetics of petroleum coke POX ash slag can be studied. At present, the study of combustion kinetics usually relies on a thermogravimetric analyzer. However, the carbon content of petroleum coke POX ash slag is low (generally between 20% and 30%), and it has characteristics such as low volatile content and low calorific value, resulting in difficult ignition, unstable combustion, and long combustion time. The thermogravimetric analyzer is not suitable for detecting the combustion kinetics of petroleum coke POX ash slag. Therefore, there is an urgent need to study a device and a corresponding method for testing the combustion kinetics of petroleum coke POX ash slag to calculate the combustion kinetics parameters of petroleum coke POX ash slag, so as to provide theoretical guidance for parameter adjustment during the combustion process of petroleum coke POX ash slag and improve the combustion efficiency. Summary of the Invention

[0003] To solve the above technical problems, the present invention proposes a device and a method for testing the combustion kinetics of petroleum coke POX ash slag.

[0004] The present invention specifically adopts the following technical solutions:

[0005] The present invention provides a device for testing the combustion kinetics of petroleum coke POX ash slag, including a heating furnace and a fluidized bed reactor arranged in the heating furnace;

[0006] The top of the fluidized bed reactor is provided with a feed inlet and an exhaust port, the bottom of the fluidized bed reactor is provided with an air inlet, and a three-way gas switching valve is arranged at the air inlet of the fluidized bed reactor. The two inlets of the three-way gas switching valve are respectively connected to an inert gas storage tank and a high-purity air storage tank;

[0007] Temperature sensors are arranged in both the heating furnace and the fluidized bed reactor. The temperature sensor of the heating furnace is arranged in the upper, middle, and lower parts of the heating furnace, and the temperature sensor in the fluidized bed reactor is arranged at the central position of the fluidized bed reactor.

[0008] Furthermore, the temperature sensors in the heating furnace and the fluidized bed reactor are connected to a temperature measuring and displaying instrument through wires.

[0009] Further, it also includes a gas collection system, which includes a condenser tube, a gas collecting bottle and a liquid discharging bottle connected in sequence. The condenser tube is communicated with the exhaust port of the fluidized bed reactor through a pipeline.

[0010] Further, a ceramic filter screen is arranged at the exhaust port of the fluidized bed reactor.

[0011] The present invention also provides a method for testing the combustion kinetics of petroleum coke POX ash residue, including the steps of:

[0012] (1) Put the fine powder of petroleum coke POX ash residue into the fluidized bed reactor, and then introduce high-purity air to make the petroleum coke POX ash residue suspend in the bed layer of the fluidized bed reactor.

[0013] (2) Use a three-way gas switching valve to switch to an inert gas storage tank, introduce inert gas into the fluidized bed reactor, and turn on the heating furnace under the protection of the inert gas to preheat the fluidized bed reactor.

[0014] (3) When the fluidized bed reactor is preheated to the set combustion reaction temperature, keep the heating furnace supplying heat continuously at this temperature, and use the three-way gas switching valve to switch to the high-purity air storage tank, introduce high-purity air into the fluidized bed reactor to make the petroleum coke POX slag carry out a combustion reaction. At the same time, the high-temperature gas generated by the combustion reaction enters the condenser tube through the exhaust port and is condensed. The formed gas and liquid are respectively collected in the gas collecting bottle and the liquid discharging bottle.

[0015] (4) When the combustion reaction reaches the set time, turn off the heating furnace. After the temperature drops to room temperature, take out the residue in the fluidized bed reactor and weigh it with a balance.

[0016] (5) According to steps (1)-(4), adjust the combustion reaction temperature and the combustion reaction time for testing to obtain the weights of the residues at different combustion reaction temperatures and different combustion reaction times.

[0017] (6) Calculate the combustion kinetic parameters of the petroleum coke POX ash residue according to the weights of the residues at different combustion reaction temperatures and different combustion reaction times obtained in step (5).

[0018] Further, in step (1), the particle size of the petroleum coke POX ash residue is 0.1-1.0 mm, and the addition amount of the petroleum coke POX ash residue is 20-50 g.

[0019] In the above technical solution, the present invention controls the particle size of the petroleum coke POX ash residue to be 0.1-1.0 mm to eliminate the influence of internal diffusion control, that is, to eliminate the influence brought by the diffusion resistance when gas molecules pass through the micropores of the petroleum coke POX ash residue.

[0020] Further, in the step (2), the flow rate of the inert gas is greater than 150 mL / min, and in the step (3), the flow rate of the high-purity air is greater than 150 mL / min.

[0021] In the above technical solution, the present invention controls the flow rates of the inert gas and the high-purity air to be greater than 150 mL / min to eliminate the influence of external diffusion, that is, to eliminate the decrease in the diffusion rate of gas molecules caused by the relatively thick stagnant film formed on the surface when gas molecules flow through the petroleum coke POX ash particles.

[0022] Further, the combustion kinetic parameters of the petroleum coke POX ash in the step (6) include the apparent activation energy and the pre-exponential factor.

[0023] Further, the step (6) is specifically as follows:

[0024] (61) Measuring the carbon content of the petroleum coke POX ash before combustion by a spectrometer and calculating the carbon content of the residue according to the weight of the residue;

[0025] (62) Determining the order n of the combustion rate of the petroleum coke POX ash with respect to the carbon content C and the order m with respect to the oxygen partial pressure P O and calculating the reaction rate constant k at different temperatures;

[0026] (63) Using the reaction rate constant data at different temperatures, plotting lnk against 1 / T, and the intercept and slope of the obtained straight line are the pre-exponential factor and the apparent activation energy of the petroleum coke POX ash, respectively, that is, obtaining the combustion kinetic parameters of the petroleum coke POX ash.

[0027] Further, the step (62) is specifically as follows: By plotting the curve of the carbon content of the petroleum coke POX ash during combustion against the reaction time C-t at different temperatures and performing linear regression on ln(-dC / dt) and lnC, the slope of the obtained straight line is n; then, performing linear regression on ln((-dC / dt) / C n ) and lnP O and the slope of the obtained straight line is m.

[0028] The present invention has the following beneficial effects:

[0029] The present invention provides a device for testing the combustion kinetics of petroleum coke POX ash, which has a simple structure and can solve the problems of difficult ignition, unstable combustion, and long combustion time of petroleum coke POX ash, thereby smoothly realizing the combustion kinetics test of petroleum coke POX ash, obtaining the combustion kinetic parameters of petroleum coke POX ash, and providing a theoretical guidance for parameter adjustment during the combustion process of petroleum coke POX ash. Description of the Drawings

[0030] Figure 1Schematic diagram of the overall structure of the test device of the present invention;

[0031] Figure 2 Curve of the C content of the petroleum coke POX ash during combustion varying with the reaction time;

[0032] Figure 3 lnC - t curve of the petroleum coke POX ash during combustion;

[0033] Figure 4 lnk - 1 / T curve of the petroleum coke POX ash during combustion.

[0034] Annotations in the figure: 1. Heating furnace; 2. Fluidized bed reactor; 201. Feed inlet; 202. Exhaust port; 203. Air inlet; 3. Three - way gas switching valve; 4. Inert gas storage tank; 5. High - purity air storage tank; 6. Temperature sensor; 7. Temperature measuring and displaying instrument; 8. Gas collection system; 801. Condensing tube; 802. Gas collecting bottle; 803. Drainage bottle. Specific implementation mode

[0035] The following further describes the specific implementation mode of the present invention in conjunction with the accompanying drawings and specific embodiments.

[0036] Refer to Figure 1 , this embodiment provides a test device for the combustion kinetics of petroleum coke POX ash, including a heating furnace 1 and a fluidized bed reactor 2 arranged in the heating furnace 1. The fluidized bed reactor 2 is used to provide a place for the combustion of the petroleum coke POX ash, and the heating furnace 1 is used to heat the fluidized bed reactor 2 to make the petroleum coke POX ash inside it burn.

[0037] The top of the above - mentioned fluidized bed reactor 2 is provided with a feed inlet 201 and an exhaust port 202, the bottom of the above - mentioned fluidized bed reactor 2 is provided with an air inlet 203, and a three - way gas switching valve 3 is arranged at the air inlet 203 of the fluidized bed reactor 2. The two inlets of the three - way gas switching valve 3 are respectively connected to the inert gas storage tank 4 and the high - purity air storage tank 5, and the outlet of the three - way gas switching valve 3 is connected to the air inlet 203 of the fluidized bed reactor 2. The type and flow rate of the gas entering the interior of the fluidized bed reactor 2 are controlled by the three - way gas switching valve 3; in addition, the above - mentioned inert gas can be nitrogen, and the oxygen purity in the above - mentioned high - purity air is 99.999%. This embodiment uses the fluidized bed reactor to carry out the combustion reaction of the petroleum coke POX ash and fills it with high - purity air. The petroleum coke POX ash suspends in the bed layer of the fluidized bed reactor and is in full contact with the high - purity air, making it ignite quickly, burn quickly and stably, so as to smoothly realize the combustion kinetics test of the petroleum coke POX ash.

[0038] Temperature sensors 6 are provided in both the above-mentioned heating furnace 1 and the fluidized bed reactor 2. The temperature sensors 6 of the heating furnace 1 are arranged at the upper, middle and lower parts of the heating furnace 1 and are used to monitor the heating temperatures in different areas of the heating furnace. The temperature sensors 6 inside the fluidized bed reactor 2 are arranged at the central position of the bed layer of the fluidized bed reactor 2 and are used to monitor the heating temperature in the reaction area of the fluidized bed reactor. Moreover, the temperature sensors 6 in the heating furnace 1 and the fluidized bed reactor 2 are connected to a temperature measuring and displaying instrument 7 through wires to monitor the reaction temperature in real time.

[0039] The test device of this embodiment further includes a gas collection system 8. The gas collection system 8 includes a condenser 801, a gas collecting bottle 802 and a liquid discharging bottle 803 which are connected in sequence. The condenser 801 is communicated with the exhaust port 202 of the fluidized bed reactor 2 through a pipeline. The condenser 801 is composed of an inner tube and an outer casing. The outer casing is used to introduce a cooling medium to cool the high-temperature gas in the inner tube of the condenser.

[0040] In addition, a ceramic filter screen is provided at the exhaust port 202 of the fluidized bed reactor 2 to prevent the particulate matter doped in the combustion gas from entering the gas collection system 8.

[0041] The combustion kinetics of petroleum coke POX ash is tested by using the above test device. In this embodiment, the petroleum coke POX ash is first dried, crushed and screened so that its particle size range is 0.1 - 1.0 mm. The fine powder of petroleum coke POX ash with a particle size range of 0.1 - 1.0 mm is used as a test sample for combustion kinetics testing. The specific steps are as follows:

[0042] (1) Put 20 g of fine powder of petroleum coke POX ash into the fluidized bed reactor, and then introduce high-purity air to make the petroleum coke POX ash suspend in the bed layer of the fluidized bed reactor.

[0043] (2) Use a three-way gas switching valve to switch to nitrogen, set the nitrogen flow rate to 200 mL / min, introduce nitrogen into the fluidized bed reactor, and start the heating furnace under nitrogen protection, set the heating furnace temperature to 500 °C, and preheat the fluidized bed reactor.

[0044] (3) When the fluidized bed reactor is preheated to the set combustion reaction temperature, keep the heating furnace supplying heat continuously at this temperature, and use the three-way gas switching valve to switch to the high-purity air storage tank. Set the high-purity air flow rate to 200 mL / min, introduce high-purity air into the fluidized bed reactor, and control the oxygen partial pressure to 0.02 MPa to make the petroleum coke POX slag undergo a combustion reaction. At the same time, the high-temperature gas generated by the combustion reaction enters the condenser through the exhaust port, and the gas and liquid formed after condensation are respectively collected in the gas collecting bottle and the liquid discharging bottle; in this embodiment, a gas bag is also connected to the gas collecting bottle for sampling and chromatographic analysis. Through chromatographic analysis, the gas element components are C and O, indicating that during the combustion process of the petroleum coke POX ash slag, mainly the carbon in it is burned;

[0045] (4) When the combustion reaction reaches the set time, turn off the heating furnace. After the temperature drops to room temperature, take out the residue in the fluidized bed reactor and weigh it using a balance;

[0046] (5) According to steps (1)-(4), place the fine powder of petroleum coke POX ash slag into the fluidized bed reactor again for testing, and adjust the combustion reaction temperature (between 500 and 700 °C) and the combustion reaction time (1 to 120 min) to obtain the weights of the residues at different combustion reaction temperatures and different combustion reaction times;

[0047] (6) According to the weights of the residues at different combustion reaction temperatures and different combustion reaction times obtained in step (5), calculate the combustion kinetic parameters of the petroleum coke POX ash slag, namely the apparent activation energy and the pre-exponential factor. The specific steps are as follows:

[0048] (61) Use a spectrometer to measure the carbon content of the petroleum coke POX ash slag before combustion, and calculate the carbon content of the residue according to the weight of the residue;

[0049] (62) Determine the order n of the combustion rate of the petroleum coke POX ash slag with respect to the carbon content C and the order m with respect to the oxygen partial pressure P O and calculate the reaction rate constant k at different temperatures. The specific calculation steps are as follows:

[0050] The combustion process of the petroleum coke POX ash slag satisfies the following equation:

[0051]

[0052] In the formula, C is the carbon content of the petroleum coke POX ash slag, n is the order of the combustion rate of the petroleum coke POX ash slag with respect to the carbon content C, P O is the oxygen partial pressure, m is the order of the combustion rate of the petroleum coke POX ash slag with respect to the oxygen partial pressure P O and t is the reaction time.

[0053] According to the above formula (1), the curve of the carbon content of the petroleum coke POX ash during combustion varying with the reaction time at different temperatures, C-t, is plotted as Figure 2 shown;

[0054] Taking the logarithm of both sides of the above formula gives:

[0055] ln(-dC / dt) = lnk + mlnP O + nlnC (2)

[0056] Since the temperature and oxygen partial pressure are constant in each experiment and only the variable C exists, the least squares method is used to perform a linear regression on ln(-dC / dt) and lnC, and the slope of the obtained straight line is n.

[0057] However, specifically in this embodiment, first assume n = 1, then integrate formula (1) to obtain:

[0058]

[0059] That is to say, if the lnC-t curve is a straight line, the combustion process of the petroleum coke POX ash satisfies formula (3), indicating that the order n of the combustion rate of the petroleum coke POX ash with respect to the carbon content C is first order.

[0060] Referring to Figure 3 , in this embodiment, the lnC-t curve is plotted, Figure 3 The reaction stage in [reference] is approximately linear. Specifically, it is about 1 - 4 minutes for the reaction stage, indicating that the order n of the combustion rate of the petroleum coke POX ash with respect to the carbon content C is first order, n = 1.

[0061] Transform the above formula (1) into formula (2), that is:

[0062]

[0063] Taking the logarithm of both sides of the above formula (4) gives:

[0064] ln[(-dC / dt) / C n = lnk + mlnP O (5)

[0065] Taking n = 1, perform a linear regression on the plot of ln[(-dC / dt) / C n and lnP O , and the slope of the obtained straight line is m, and it is calculated that m = 0.5.

[0066] According to the above n = 1, m = 0.5, using formula (1) to transform it into The reaction rate constant k at different reaction temperatures can be solved as shown in Table 1 below:

[0067] Table 1 Reaction rate constants at different temperatures

[0068]

[0069] (63) Using the reaction rate constant data at different temperatures, plot lnk against 1 / T. The intercept and slope of the resulting straight line are the pre-exponential factor and the apparent activation energy of the petroleum coke POX ash respectively, that is, the combustion kinetic parameters of the petroleum coke POX ash are obtained. The specific calculation steps are as follows:

[0070] According to the Arrhenius equation:

[0071]

[0072] Taking the logarithm of both sides of the above formula (6) gives:

[0073]

[0074] According to the data in Table 1, plot lnk against 1 / T, and a good straight line is obtained, as Figure 4 shown. The intercept and slope of this straight line are the pre-exponential factor and the apparent activation energy of the petroleum coke POX ash respectively, and A = 7.981×10 5 min -1 is obtained, Ea = 82.286 kJ / mol. Thus, the relationship between the reaction rate constant and temperature of the petroleum coke POX ash is: k = 7.981×10 5 ×exp(82.286×10 3 / RT).

[0075] Through the above relationship, the relationship between the reaction rate constant and temperature of the petroleum coke POX ash is obtained. During the combustion process of the petroleum coke POX ash, the reaction temperature can be adjusted according to the required reaction rate.

[0076] It should be noted that the parts not described in this embodiment are obtained by using the existing technology.

[0077] Of course, the above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by those skilled in the art within the scope of the essence of the present invention should also fall within the protection scope of the present invention.

Claims

1. A test device for the combustion kinetics of petroleum coke POX ash residue, characterized in that, It includes a heating furnace and a fluidized bed reactor disposed inside the heating furnace; At the top of the fluidized bed reactor, there are a feed inlet and an exhaust port. At the bottom of the fluidized bed reactor, there is an air inlet, and a three-way gas switching valve is provided at the air inlet of the fluidized bed reactor. The two inlets of the three-way gas switching valve are respectively connected to an inert gas storage tank and a high-purity air storage tank; Temperature sensors are provided both inside the heating furnace and the fluidized bed reactor. The temperature sensors of the heating furnace are arranged at the upper, middle, and lower parts of the heating furnace, and the temperature sensor inside the fluidized bed reactor is arranged at the central position of the fluidized bed reactor.

2. The petroleum coke POX ash combustion kinetics testing device according to claim 1, wherein, The temperature sensors inside the heating furnace and the fluidized bed reactor are connected to a temperature measuring and displaying instrument through wires.

3. A kinetic test device for petroleum coke POX ash residue combustion according to claim 1, characterized in that, It further includes a gas collection system. The gas collection system includes a condenser tube, a gas collecting bottle, and a liquid discharging bottle connected in sequence. The condenser tube is communicated with the exhaust port of the fluidized bed reactor through a pipeline.

4. The petroleum coke POX slag combustion kinetics testing device according to claim 3, characterized in that, A ceramic filter screen is provided at the exhaust port of the fluidized bed reactor.

5. A method for testing the combustion kinetics of petroleum coke POX ash, using the testing device described in any one of claims 1-4, characterized in that, It includes steps: (1) Put the petroleum coke POX ash fine powder into the fluidized bed reactor, and then introduce high-purity air to make the petroleum coke POX ash suspended in the bed layer of the fluidized bed reactor; (2) Use the three-way gas switching valve to switch to the inert gas storage tank, introduce inert gas into the fluidized bed reactor, and under the protection of inert gas, turn on the heating furnace to preheat the fluidized bed reactor; (3) When the fluidized bed reactor is preheated to the set combustion reaction temperature, keep the heating furnace continuously supplying heat at this temperature, and use the three-way gas switching valve to switch to the high-purity air storage tank, introduce high-purity air into the fluidized bed reactor to make the petroleum coke POX slag undergo a combustion reaction. At the same time, the high-temperature gas generated by the combustion reaction enters the condenser tube through the exhaust port. The gas and liquid formed after condensation are respectively collected in the gas collecting bottle and the liquid discharging bottle; (4) When the combustion reaction reaches the set time, turn off the heating furnace. After the temperature drops to room temperature, take out the residue in the fluidized bed reactor and weigh it using a balance; (5) According to steps (1)-(4), adjust the combustion reaction temperature and combustion reaction time for testing to obtain the weights of the residues at different combustion reaction temperatures and different combustion reaction times; (6) According to the weights of the residues at different combustion reaction temperatures and different combustion reaction times obtained in step (5), calculate the combustion kinetic parameters of the petroleum coke POX ash.

6. A method for testing the combustion kinetics of petroleum coke POX ash residue according to claim 5, characterized in that, In step (1), the particle size of the petroleum coke POX ash is 0.1 - 1.0 mm.

7. A method for testing the combustion kinetics of petroleum coke POX ash residue according to claim 5, characterized in that, In step (3), the flow rate of high-purity air is greater than 150 mL / min.

8. A method for testing the combustion kinetics of petroleum coke POX ash residue according to claim 5, characterized in that, In step (6), the combustion kinetic parameters of the petroleum coke POX ash include the apparent activation energy and the pre-exponential factor.

9. A method for testing the combustion kinetics of petroleum coke POX ash residue according to claim 8, characterized in that, Step (6) is specifically as follows: (61) Use a spectrometer to measure the carbon content of the petroleum coke POX ash before combustion, and calculate the carbon content of the residue according to the weight of the residue; (62) Determine the order n of the combustion rate of petroleum coke POX ash residue with respect to carbon content C and the order m with respect to oxygen partial pressure P O and calculate the reaction rate constant k at different temperatures; (63) Use the reaction rate constant data at different temperatures to plot lnk against 1 / T. The intercept and slope of the obtained straight line are respectively the pre-exponential factor and the apparent activation energy of the petroleum coke POX ash, that is, the combustion kinetic parameters of the petroleum coke POX ash are obtained.

10. A method for testing the combustion kinetics of petroleum coke POX ash residue according to claim 9, characterized in that, The specific steps of step (62) are as follows: By plotting the change curve C-t of the carbon content of the petroleum coke POX ash during the combustion process at different temperatures with respect to the reaction time, performing a linear regression on ln(-dC / dt) and lnC, the slope of the obtained straight line is n; then performing a linear regression on ln((-dC / dt) / C n ) and lnP O , and the slope of the obtained straight line is m.

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