Method for calculating lost propylene during regeneration of propylene protection bed and liquid phase dryer of olefin device
By calculating the total volume of the equipment, the filling volume of the porcelain ball and molecular sieve and the void volume, combined with the pore volume calculation method, the problem of large error in estimation of propylene loss during regeneration of propylene protection bed and liquid phase desiccant in the prior art is solved, and the accurate calculation of propylene loss and stable control of production costs are achieved.
Patent Information
- Application Number
- CN202510235541.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-28
- Publication Date
- 2025-07-08
AI Technical Summary
In the prior art, the estimation error of the amount of propylene loss during regeneration of propylene protection bed and liquid phase desiccant is large, and it is impossible to accurately calculate the pore size between molecular sieve and the volume between porcelain balls, resulting in difficult to control production costs and affecting corporate benefits.
By calculating the total volume of the equipment of the propylene protective bed and liquid phase dryer, the filling volume of the porcelain ball and molecular sieve and the void volume, combined with the pore volume calculation method, the loss of propylene during regeneration is accurately estimated.
The accurate calculation of the propylene loss during regeneration of propylene protective bed and liquid phase desiccant is achieved, and the production cost is controlled stably and efficiently, which improves economic benefits.
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Figure CN120280008A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of olefin production, and particularly relates to a calculation method for the loss of propylene during the regeneration of a propylene guard bed and a liquid-phase dryer in an olefin plant. Background Art
[0002] In a methanol-to-olefin plant, a propylene guard bed and a liquid-phase dryer play a crucial role. They use molecular sieves to adsorb methanol and water in the product to ensure the smooth progress of the subsequent process. However, there are many problems in the prior art. When the adsorption is saturated, these devices need to be taken out for regeneration. During this period, the amount of propylene lost is estimated only by the time of supplementing liquid-phase propylene. This estimation method has serious defects. On the one hand, the estimated value deviates greatly from the actual loss amount, which cannot provide accurate data support for the production process, resulting in difficult precise control of production costs and affecting the enterprise benefits. On the other hand, the prior art cannot measure the pore volume between molecular sieves and the void volume between porcelain balls. The lack of these two key parameters makes the calculation of propylene loss lack a scientific basis and further exacerbates the calculation error. Summary of the Invention
[0003] The purpose of the present invention is to solve the above problems and design a calculation method for the loss of propylene during the regeneration of a propylene guard bed and a liquid-phase dryer in an olefin plant.
[0004] The present invention provides a calculation method for the loss of propylene during the regeneration of a propylene guard bed and a liquid-phase dryer in an olefin plant. The calculation method for the loss of propylene during the regeneration of the propylene guard bed and the liquid-phase dryer in the olefin plant includes the following steps:
[0005] Step 1: Calculate the total volume of the equipment of the propylene guard bed and the liquid-phase dryer respectively, and determine the designed volume of the porcelain ball molecular sieve filling.
[0006] Step 2: Calculate the actual volume of the porcelain ball and molecular sieve filling according to the specifications and models of the porcelain balls and molecular sieves filled in the propylene guard bed and the liquid-phase dryer.
[0007] Step 3: Perform a volume difference operation based on the total volume of the equipment of the propylene guard bed and the liquid-phase dryer, the designed volume of the porcelain ball molecular sieve filling, and the actual volume of the porcelain ball and molecular sieve filling calculated in Step 1 and Step 2, and calculate the void volume between the porcelain balls and the molecular sieves.
[0008] Step 4: Calculate the pore volume of the molecular sieve by using a pore volume calculation method.
[0009] Step 5: Calculate the loss of propylene during the regeneration of the propylene guard bed and the liquid-phase dryer according to the void volume between the porcelain balls and the molecular sieves calculated in Step 3 and the pore volume of the molecular sieve calculated in Step 4.
[0010] Optionally, in the first implementation manner of the present invention, the propylene guard bed in step one consists of an elliptical head and a cylindrical part. The specifications of the elliptical head of the propylene guard bed are Φ2600×716mm, and the specifications of the cylinder are Φ2600×9820mm;
[0011] The process of calculating the total volume of the equipment of the propylene guard bed in step one is as follows:
[0012]
[0013] Among them, V 保护床 represents the total volume of the equipment of the propylene guard bed, V 1椭圆 represents the volume of the elliptical head part of the propylene guard bed, V 1圆筒 represents the volume of the cylindrical part of the propylene guard bed. a1, b1, and c1 respectively represent the semi-axis lengths of the elliptical part of the propylene guard bed, r1 represents the radius of the cylindrical part of the propylene guard bed, and h1 represents the height of the cylindrical part of the propylene guard bed.
[0014] Optionally, in the second implementation manner of the present invention, the liquid-phase dryer in step one consists of an elliptical head and a cylindrical part. The specifications of the elliptical head of the liquid-phase dryer are Φ2400×670mm, and the specifications of the cylinder are Φ2400×11820mm;
[0015] The process of calculating the total volume of the equipment of the liquid-phase dryer in step one is as follows:
[0016]
[0017] Among them, V 干燥器 represents the total volume of the equipment of the liquid-phase dryer, V 2椭圆 represents the volume of the elliptical head part of the liquid-phase dryer, V 2圆筒 represents the volume of the cylindrical part of the liquid-phase dryer. a2, b2, and c2 respectively represent the semi-axis lengths of the elliptical part of the liquid-phase dryer, r2 represents the radius of the cylindrical part of the liquid-phase dryer, and h2 represents the height of the cylindrical part of the liquid-phase dryer.
[0018] Optionally, in the third implementation manner of the present invention, the calculation processes of the designed volumes of the porcelain ball molecular sieve filling in the propylene guard bed and the liquid-phase dryer in step one are both as follows:
[0019]
[0020] Among them, V 填料(床层高度) represents the total volume of the packing calculated according to the bed height in the propylene guard bed or the liquid-phase dryer, V 瓷球 represents the volume of the porcelain balls, V 分子筛V represents the volume of the molecular sieve, r3 represents the inner radius of the device, h3 represents the height of the porcelain balls in the bed, and h4 represents the height of the molecular sieve in the bed.
[0021] Optionally, in the fourth implementation mode of the present invention, the calculation process of the actual filling volume of the porcelain balls and molecular sieves in the propylene guard bed and the liquid phase dryer in step two is as follows: the actual filling volume of the porcelain balls = the volume of a single porcelain ball × the number of porcelain balls, and the actual filling volume of the molecular sieve is calculated according to the actual filling quantity and the volume parameter of a single molecular sieve.
[0022] Optionally, in the fifth implementation mode of the present invention, the calculation process of the actual filling volume of the porcelain balls and molecular sieves in the propylene guard bed and the liquid phase dryer in step three is as follows: the actual filling volume of the porcelain balls and molecular sieves = the total volume of the device - the actual filling volume of the porcelain balls - the actual filling volume of the molecular sieve.
[0023] Optionally, in the sixth implementation mode of the present invention, the calculation process of the pore volume of the molecular sieve in the propylene guard bed and the liquid phase dryer in step four is as follows: V 孔体积 = filling volume × bulk density × pore volume.
[0024] Optionally, in the seventh implementation mode of the present invention, the calculation process of the lost propylene during the regeneration of the propylene guard bed and the liquid phase dryer in step five is as follows: the lost propylene during regeneration = the lost propylene amount in the unfilled part + the lost propylene amount in the voids during regeneration + the adsorbed propylene lost amount during regeneration.
[0025] In the technical solution provided by the present invention, by calculating the total volume of the propylene guard bed and the liquid phase dryer respectively, determining the designed filling volume of the porcelain balls and molecular sieves, calculating the actual filling volume of the porcelain balls and molecular sieves according to the specifications and models of the filled porcelain balls and molecular sieves in the propylene guard bed and the liquid phase dryer, performing volume difference operations based on the calculated total volume of the propylene guard bed and the liquid phase dryer, the designed filling volume of the porcelain balls and molecular sieves, and the actual filling volume of the porcelain balls and molecular sieves, calculating the void volume between the porcelain balls and molecular sieves, using the pore volume calculation method to calculate the pore volume of the molecular sieve; calculating the lost propylene during the regeneration of the propylene guard bed and the liquid phase dryer according to the calculated void volume between the porcelain balls and molecular sieves and the pore volume of the molecular sieve calculated in step four; the present invention realizes the accurate calculation of the lost propylene amount during the regeneration of the propylene guard bed and the liquid phase dryer, realizes the accurate calculation of the pore volume between the molecular sieves and the void volume between the porcelain balls, and the provided calculation method can play a stable and efficient role in the daily operation of the olefin plant, effectively control the production cost, and improve the economic benefits. Description of the Drawings
[0026] Upon reading the following detailed description of the preferred embodiments, various other advantages and benefits will become apparent to those of ordinary skill in the art. The accompanying drawings are provided only for the purpose of illustrating the preferred embodiments and are not considered to be a limitation of the present invention.
[0027] Figure 1 Schematic diagram of the calculation method for the loss of propylene during the regeneration of the propylene protection bed and the liquid-phase dryer in the olefin plant provided by the embodiment of the present invention;
[0028] Figure 2 Schematic diagram of the operating conditions of the propylene protection bed provided by the embodiment of the present invention;
[0029] Figure 3 Schematic diagram of the performance indicators of the alcohol removal agent provided by the embodiment of the present invention. Specific Embodiments
[0030] The terms "first", "second", "third", "fourth", etc. (if any) in the specification, claims and above-mentioned drawings of the present invention are used to distinguish similar objects and do not necessarily have to be used to describe a specific order or sequence. It should be understood that such used data can be interchanged under appropriate circumstances so that the embodiments described herein can be implemented in an order different from that shown or described herein. In addition, the term "comprising" or "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, device, product or equipment comprising a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or equipment.
[0031] For ease of understanding, the following describes the specific process of the embodiment of the present invention. Please refer to Figure 1 Schematic diagram of the calculation method for the loss of propylene during the regeneration of the propylene protection bed and the liquid-phase dryer in the olefin plant provided by the embodiment of the present invention. The method specifically includes the following steps:
[0032] Step 1: Calculate the total volume of the equipment of the propylene protection bed and the liquid-phase dryer respectively, and determine the designed volume of the packing of porcelain balls and molecular sieves;
[0033] Step 2: Calculate the actual volume of the packing of porcelain balls and molecular sieves according to the specifications and models of the porcelain balls and molecular sieves packed in the propylene protection bed and the liquid-phase dryer;
[0034] Step 3: Perform a volume difference operation based on the total volume of the equipment of the propylene protection bed and the liquid-phase dryer, the designed volume of the packing of porcelain balls and molecular sieves, and the actual volume of the packing of porcelain balls and molecular sieves calculated in Step 1 and Step 2, and calculate the void volume between the porcelain balls and the molecular sieves;
[0035] Step 4: Calculate the pore volume of the molecular sieve by using the pore volume calculation method;
[0036] Step 5: Calculate the loss of propylene during the regeneration of the propylene guard bed and the liquid-phase dryer based on the void volume between the porcelain balls and the molecular sieve obtained in Step 3 and the pore volume of the molecular sieve obtained in Step 4.
[0037] In this embodiment, in Step 1, the propylene guard bed consists of an elliptical head and a cylindrical part. The specifications of the elliptical head of the propylene guard bed are Φ2600×716 mm, and the specifications of the cylinder are Φ2600×9820 mm.
[0038] The process of calculating the total volume of the equipment of the propylene guard bed in Step 1 is as follows:
[0039]
[0040] Among them, V 保护床 represents the total volume of the equipment of the propylene guard bed, V 1椭圆 represents the volume of the elliptical head part of the propylene guard bed, V 1圆筒 represents the volume of the cylindrical part of the propylene guard bed. a1, b1, and c1 respectively represent the semi-axis lengths of the elliptical part of the propylene guard bed, r1 represents the radius of the cylindrical part of the propylene guard bed, and h1 represents the height of the cylindrical part of the propylene guard bed. In this elliptical head of the propylene guard bed, a1 = b1 = 1.3 m, the head radius is obtained by dividing the diameter of 2.6 m by 2, and c1 is the height of the curved surface part of the head. When calculating, the total height of the head of 0.716 m minus the straight edge height of 0.04 m is used.
[0041] In this embodiment, in Step 1, the liquid-phase dryer consists of an elliptical head and a cylindrical part. The specifications of the elliptical head of the liquid-phase dryer are Φ2400×670 mm, and the specifications of the cylinder are Φ2400×11820 mm.
[0042] The process of calculating the total volume of the equipment of the liquid-phase dryer in Step 1 is as follows:
[0043]
[0044] Among them, V 干燥器 represents the total volume of the equipment of the liquid-phase dryer, V 2椭圆 represents the volume of the elliptical head part of the liquid-phase dryer, V 2圆筒 represents the volume of the cylindrical part of the liquid-phase dryer. a2, b2, and c2 respectively represent the semi-axis lengths of the elliptical part of the liquid-phase dryer, r2 represents the radius of the cylindrical part of the liquid-phase dryer, and h2 represents the height of the cylindrical part of the liquid-phase dryer.
[0045] In this embodiment, the calculation process of the designed volume of the porcelain ball molecular sieve filling in the propylene guard bed and the liquid-phase dryer in Step 1 is as follows:
[0046]
[0047] Among them, V 填料(床层高度) represents the total volume of the packing calculated according to the bed height in the propylene protection bed or the liquid-phase dryer, and V 瓷球 represents the volume of the porcelain balls, and V 分子筛 represents the volume of the molecular sieve. r3 represents the inner radius of the equipment, h3 represents the height of the porcelain balls in the bed, and h4 represents the height of the molecular sieve in the bed.
[0048] In this embodiment, the calculation processes of the actual filled volumes of the porcelain balls and the molecular sieve in the propylene protection bed and the liquid-phase dryer in step two are both as follows: the actual filled volume of the porcelain balls = the volume of a single porcelain ball × the number of porcelain balls, and the actual filled volume of the molecular sieve is calculated based on the actual filling quantity and the volume parameter of a single molecular sieve.
[0049] In this embodiment, the calculation processes of the actual filled volumes of the porcelain balls and the molecular sieve in the propylene protection bed and the liquid-phase dryer in step three are both as follows: the actual filled volume of the porcelain balls and the molecular sieve = the total volume of the equipment - the actual filled volume of the porcelain balls - the actual filled volume of the molecular sieve.
[0050] In this embodiment, the calculation processes of the pore volume of the molecular sieve in the propylene protection bed and the liquid-phase dryer in step four are both as follows: V 孔体积 = filled volume × bulk density × pore volume.
[0051] In this embodiment, the calculation process of the lost propylene during the regeneration of the propylene protection bed and the liquid-phase dryer in step five is both as follows: the lost propylene during regeneration = the lost propylene amount in the unfilled packing part + the lost propylene amount in the voids during regeneration + the adsorbed propylene lost amount during regeneration.
[0052] In this embodiment, the calculation of the loss of propylene during the regeneration of the propylene guard bed and the liquid-phase dryer focuses on fully considering the spatial factors related to propylene storage in the internal structure of the equipment, namely the void volume between the porcelain balls and the molecular sieve and the pore volume of the molecular sieve; these two volume parameters respectively represent the spaces that can accommodate propylene at the macroscopic and microscopic levels within the equipment; when the equipment enters the regeneration stage, the propylene stored in these spaces will migrate or escape due to changes in conditions such as temperature and pressure, resulting in propylene loss; by accurately calculating these two key volume parameters and combining the physical and chemical conditions during the regeneration process, the amount of propylene loss can be estimated more accurately; the change in temperature during the regeneration process will significantly affect the state of propylene in the voids and the molecular sieve pores; when the temperature rises, the thermal motion of propylene molecules intensifies, the adsorption equilibrium of propylene in the molecular sieve pores is broken, and part of the propylene originally adsorbed in the pores will desorb and enter the void space, and at the same time, the propylene in the voids will also diffuse out of the equipment due to thermal expansion; it is necessary to monitor the temperature change curve during the regeneration process in real time and understand the physical property parameters such as the saturated vapor pressure of propylene at different temperatures; the change in pressure directly affects the flow direction and rate of propylene; during the regeneration process, the equipment is usually depressurized to promote the desorption of impurities and propylene adsorbed on the molecular sieve; the change in pressure will cause the propylene in the voids and the molecular sieve pores to flow towards the direction with lower pressure; record the pressure change situation during the regeneration process, and according to the ideal gas state equation, the change in the amount of substance of propylene in the voids and pores under different pressure conditions can be calculated, and then the propylene loss situation can be evaluated; the diffusion process of propylene in the voids and the molecular sieve pores cannot be ignored; the diffusion coefficient \(D\) is related to temperature, pressure, and the properties of propylene itself, and the diffusion behavior of propylene in different spaces can be described by Fick's law (such as Fick's first law); considering the complex structure of the voids and the molecular sieve pores, numerical simulation methods (such as finite element analysis, molecular dynamics simulation, etc.) may be required to more accurately calculate the diffusion process and diffusion amount of propylene.
[0053] Example 1.
[0054] The operating conditions of the propylene guard bed are as Figure 2 shown. The elliptical head of the propylene guard bed: (including the straight height of 40 mm), the cylinder: φ2600*9820 mm,
[0055]
[0056] V 保护床 =(4 / 3*3.14*1.3*1.3*(0.716 - 0.04))+(3.14*1.3*1.3*(9.82 + 0.04 + 0.04)) = 57.32 m 3
[0057]
[0058] V 填料(床层高度) = 3.14 * 1.3 * 1.3 * (7.6 + 0.15 + 0.15) = 41.9221 m 3
[0059] V 放火炬 = V 保护床 - V 填料(床层高度) = 15.4 m 3
[0060] Among them, the volume of the flare is the part without packing;
[0061] 1. The calculation process of the propylene loss amount in the part without packing (propylene loss 1) during flaring is: the flaring amount is m = ρV 放火炬 = 27.24673 kg, where the density of propylene at 0.1 MPa and 25 °C is 1.7885 kg / m 3 .
[0062] 2. The calculation process of the propylene loss amount in the voids during regeneration (propylene loss 2) is:
[0063] First, calculate the propylene loss amount in the voids of the packing during regeneration:
[0064] V 填料间空隙
[0065] = V 填料(床层高度) - V 填料(实际填装数量) = V 填料(床层高度) - V 瓷球(实际填装数量) - V 分子筛(实际填装数量) = 0.76233192 m 3
[0066] Then, the propylene loss amount in the voids during regeneration is: m = ρV 填料间空隙 = 0.391762374 t, where the actual packing volume is 40.33 m 3 , and the liquid density of propylene is calculated as 0.5139 t / m 3 ;
[0067] Actual filling volume of porcelain balls: Given the specification of porcelain balls, assuming the porcelain balls are regularly arranged, 2544 porcelain balls can be filled in each layer. If the total number of layers filled in the upper and lower parts of the protection bed is [specific number of layers], then the total number of porcelain balls is 2544×[number of layers] = [specific number] pieces. According to the volume of a single porcelain ball, the actual filling volume of porcelain balls can be calculated as [specific calculation process and result, e.g., actual filling volume of porcelain balls = [volume of a single porcelain ball]×[number of porcelain balls]; Actual filling volume of molecular sieve: Based on the specification model of the molecular sieve, according to its packing density and other parameters, combined with the actual filling method and quantity, the actual filling volume of the molecular sieve is calculated as [specific calculation process and result, e.g., calculated based on the actual filling quantity and relevant volume parameters of a single molecular sieve.
[0068] The height of the porcelain ball bed layer is 150mm×2, assuming the porcelain balls are neatly arranged, then 10 layers can be filled in the 150mm inner shell, and 23494 porcelain balls can be filled in each layer. Then the total number of porcelain balls filled in the upper and lower layers of the protection bed is 23494×10×2 = 469880 pieces. The volume of each porcelain ball is 4 / 3×3.14×0.0075×0.0075×0.0075 = 1.766×10 -6 , then the volume of all porcelain balls in the protection bed is 469880×0.000001766 = 0.82980808m 3 ;
[0069] In principle, propylene is not absorbed in the pore diameter of the alcohol removal agent. Here, it is assumed that all propylene is absorbed in the pore diameter of the alcohol removal agent. The performance indicators of the alcohol removal agent are as Figure 3 shown, then:
[0070] (1) Calculated by adsorption rate
[0071] Static methanol adsorption (mass percentage): ≥15%
[0072] Then after regeneration, the volume of adsorbed methanol is filled by propylene, and the consumption of propylene is 40.33×0.15×0.5139t = 3.10883805t
[0073] (2) Calculated by pore volume
[0074] V 孔容积 = filling volume×packing density×pore volume = 40.33×0.7×0.4 = 11.2924
[0075] Then after regeneration, the pore volume is filled by propylene, and the consumption of propylene is V 孔容积 ×0.5139 = 5.80316436t.
[0076] 3. During regeneration, the adsorbed propylene loss is 3.11 - 5.80 t. This loss range may be due to different assumptions or calculation methods used in calculating the adsorption loss, resulting in fluctuations in the results. For example, different methods such as calculating by adsorption rate and by pore volume may have been considered before, and the amount of propylene adsorbed varies under each method, thus obtaining such a loss range;
[0077] The total propylene loss in the regenerated propylene protection bed is = Loss of propylene 1 + Loss of propylene 2 + Loss of propylene 3, approximately 3.43 - 6.23 t. This range is jointly determined by the fluctuation range of Loss of propylene 3 plus the relatively fixed Loss of propylene 1 and Loss of propylene 2, reflecting the overall range of propylene loss during the regeneration of the propylene protection bed when considering different adsorption situations; if the adsorption of the alcohol removal agent is not considered, the loss amount is 0.42 t. This value only includes the propylene loss from flaring and the propylene loss in the voids during regeneration, excluding the influence of the adsorption of the alcohol removal agent. By comparing the loss amounts with and without considering adsorption, the influence degree of the adsorption of the alcohol removal agent on propylene loss can be more clearly understood.
[0078] Example 2.
[0079] Liquid-phase dryer: Elliptical head: (including a straight height of 40 mm), Cylinder: φ2400 * 11820 mm,
[0080]
[0081] V 干燥器 =(4 / 3 * 3.14 * 1.2 * 1.2 * (0.670 - 0.04)) + (3.14 * 1.2 * 1.2 * (11.82 + 0.04 + 0.04)) = 57.61 m 3
[0082]
[0083] V 填料(床层高度) = 3.14 * 1.2 * 1.2 * (9.5 + 0.15 + 0.15) = 44.7638 m 3
[0084] V 放火炬 = V 保护床 - V 填料(床层高度) = 12.841344 m 3
[0085] Among them, the volume of the flared part is the part without packing;
[0086] 1. The calculation process of the propylene loss amount in the part without packing (Loss of propylene 1) is: The flared amount is m = ρV 放火炬= 22.966743744 kg, where the density of propylene at 0.1 MPa and 25 °C is 1.7885 kg / m 3 .
[0087] 2. The calculation process of the propylene loss (lost propylene 2) in the voids during regeneration is as follows:
[0088] First, calculate the propylene loss in the voids of the packing during regeneration:
[0089] V 填料间空隙
[0090] = V 填料(床层高度) - V 填料(实际填装数量) = V 填料(床层高度) - V 瓷球(实际填装数量) - V 分子筛(实际填装数量) = 0.65404928 m 3
[0091] Then, the propylene loss in the voids during regeneration is: m = ρV 填料间空隙 = 0.336115925 t, where the actual filling volume is 43.4 m 3 , and the density of the propylene liquid is 0.5139 t / m 3 ;
[0092] Actual filling volume of porcelain balls: Assume that 2006 porcelain balls can be filled in each layer. If the total number of layers filled up and down in the dryer is [specific number of layers], then the total number of porcelain balls is 2006 × [number of layers] = [specific number]. According to the volume of a single porcelain ball, calculate the actual filling volume of the porcelain balls as [specific calculation process and result, e.g., actual filling volume of porcelain balls = [volume of a single porcelain ball] × [number of porcelain balls]; Actual filling volume of molecular sieve: According to the specification model of the molecular sieve, through parameters such as its bulk density and combined with the actual filling situation, calculate the actual filling volume of the molecular sieve as [specific calculation process and result, e.g., calculated based on the actual filling quantity and relevant volume parameters of a single molecular sieve.
[0093] The height of the porcelain ball bed layer is 150 mm * 2. Assume the porcelain balls are neatly arranged. Then, 10 layers can be filled within 150 mm of the inner shell, and 20096 porcelain balls can be filled in each layer. So, the total number of porcelain balls filled in the upper and lower layers of the protection bed is 20096 * 10 * 2 = 401920. The volume of each porcelain ball is 4 / 3 * 3.14 * 0.0075 * 0.0075 * 0.0075 = 1.766 * 10 -6 , and the total volume of all porcelain balls in the protection bed is 401920 * 0.000001766 = 0.70979072 m 3 ;
[0094] In principle, propylene is not absorbed in the pores of strip 3A-EPG1 / 16. Assuming that all propylene is absorbed in the pores of strip 3A-EPG1 / 16, then:
[0095] (1) Calculated by adsorption rate
[0096] Static methanol adsorption (mass percentage): ≥19%
[0097] After regeneration is completed, the volume of adsorbed methanol is filled by propylene, and the consumed propylene amount is 43.4 * 0.19 * 0.5139t = 4.2376194t
[0098] 3. The loss of adsorbed propylene during regeneration is 4.2376194t. This part of the loss may be caused by the adsorption of propylene by the relevant adsorbent during the regeneration process. This value is calculated through an adsorption calculation model, considering the adsorption performance parameters of the adsorbent (such as adsorption rate, pore volume, etc.) and the filling situation in the equipment, etc.;
[0099] The total loss of propylene in the propylene protection bed during regeneration = loss of propylene 1 + loss of propylene 2 + loss of propylene 3; it is approximately 4.5967t. If water adsorption is not considered, the loss amount is 0.3591t. At this time, the loss amount only includes the loss of propylene discharged to the flare and the loss of propylene in the voids during regeneration, excluding the influence of adsorption on propylene loss. Through this comparison, the proportion of adsorption factors in propylene loss can be more clearly understood.
[0100] Through the above embodiments, the accurate calculation of the loss of propylene during the regeneration of the propylene protection bed and the liquid-phase dryer is realized, and the accurate calculation of the pore volume between molecular sieves and the void volume between porcelain balls is realized. The provided calculation method can play a stable and efficient role in the daily operation of the olefin plant, effectively control production costs, and improve economic benefits.
[0101] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. The above embodiments and the descriptions in the specification are only preferred examples of the present invention and are not used to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.
Claims
1. A calculation method for the loss of propylene during the regeneration of the propylene protection bed and the liquid-phase dryer in an olefin plant, characterized in that, The calculation method for the loss of propylene during the regeneration of the propylene guard bed and the liquid-phase dryer in the olefin plant includes the following steps: Step 1: Calculate the total volume of the equipment for the propylene guard bed and the liquid-phase dryer respectively, and determine the designed volume of the packing of porcelain balls and molecular sieves; Step 2: Calculate the actual volume of the packing of porcelain balls and molecular sieves according to the specifications and models of the porcelain balls and molecular sieves packed in the propylene guard bed and the liquid-phase dryer; Step 3: Perform a volume difference operation based on the total volume of the equipment for the propylene guard bed and the liquid-phase dryer, the designed volume of the packing of porcelain balls and molecular sieves, and the actual volume of the packing of porcelain balls and molecular sieves obtained in Step 1 and Step 2 to calculate the void volume between the porcelain balls and the molecular sieves; Step 4: Calculate the pore volume of the molecular sieves using the pore volume calculation method; Step 5: Calculate the loss of propylene during the regeneration of the propylene guard bed and the liquid-phase dryer based on the void volume between the porcelain balls and the molecular sieves obtained in Step 3 and the pore volume of the molecular sieves obtained in Step 4.
2. The calculation method for the loss of propylene during the regeneration of the propylene guard bed and the liquid phase dryer in an olefin plant as described in claim 1, wherein In Step 1, the propylene guard bed consists of an elliptical head and a cylindrical part. The specifications of the elliptical head of the propylene guard bed are Φ2600×716mm, and the specifications of the cylinder are Φ2600×9820mm; The process of calculating the total volume of the equipment for the propylene guard bed in Step 1 is: Among them, V 保护床 represents the total volume of the equipment of the propylene guard bed, represents the volume of the elliptical head part of the propylene guard bed, represents the volume of the cylindrical part of the propylene guard bed. a1, b1, and c1 respectively represent the semi-axis lengths of the elliptical part of the propylene guard bed, r1 represents the radius of the cylindrical part of the propylene guard bed, and h1 represents the height of the cylindrical part of the propylene guard bed.
3. The calculation method for the loss of propylene during the regeneration of the propylene guard bed and the liquid phase dryer in an olefin plant as described in claim 1, characterized in that, In Step 1, the liquid-phase dryer consists of an elliptical head and a cylindrical part. The specifications of the elliptical head of the liquid-phase dryer are Φ2400×670mm, and the specifications of the cylinder are Φ2400×11820mm; The process of calculating the total volume of the equipment for the liquid-phase dryer in Step 1 is: Among them, V 干燥器 represents the total volume of the equipment of the liquid-phase dryer, represents the volume of the elliptical head part of the liquid-phase dryer, represents the volume of the cylindrical part of the liquid-phase dryer. a2, b2, and c2 respectively represent the semi-axis lengths of the elliptical part of the liquid-phase dryer, r2 represents the radius of the cylindrical part of the liquid-phase dryer, and h2 represents the height of the cylindrical part of the liquid-phase dryer.
4. The calculation method for the loss of propylene during the regeneration of the propylene guard bed and the liquid-phase dryer in an olefin plant as described in claim 1, wherein, The process of calculating the designed volume of the packing of porcelain balls and molecular sieves for the propylene guard bed and the liquid-phase dryer in Step 1 is: Among them, V 填料(床层高度) represents the total volume of the packing calculated according to the bed height in the propylene protection bed or the liquid phase dryer, V 瓷球 represents the volume of the porcelain balls, V 分子筛 represents the volume of the molecular sieve, r3 represents the inner radius of the equipment, h3 represents the height of the porcelain balls in the bed, and h4 represents the height of the molecular sieve in the bed.
5. The calculation method for the loss of propylene during the regeneration of the propylene guard bed and the liquid phase dryer in an olefin plant as described in claim 1, wherein, In Step 2, the process of calculating the actual volume of the packing of porcelain balls and molecular sieves for the propylene guard bed and the liquid-phase dryer is: the actual volume of the porcelain balls packed = the volume of a single porcelain ball × the number of porcelain balls, and the actual volume of the molecular sieves packed is calculated according to the actual filling quantity and the volume parameter of a single molecular sieve.
6. The calculation method of propylene loss during the regeneration of the propylene protection bed and the liquid phase dryer in an olefin plant as described in claim 1, characterized in that, In Step 3, the process of calculating the actual volume of the packing of porcelain balls and molecular sieves in the propylene guard bed and the liquid-phase dryer is: the actual volume of the packing of porcelain balls and molecular sieves = the total volume of the equipment - the actual volume of the porcelain balls packed - the actual volume of the molecular sieves packed.
7. The calculation method of propylene loss during the regeneration of the propylene protection bed and the liquid phase dryer in an olefin plant as described in claim 1, characterized in that, In Step 4, the calculation process for the pore volume of the molecular sieve in both the propylene guard bed and the liquid-phase dryer is as follows: V 孔体积 = Packing volume × Bulk density × Pore volume.
8. The calculation method for the loss of propylene during the regeneration of the propylene guard bed and the liquid-phase dryer in an olefin plant as described in claim 1, characterized in that, In Step 5, the process of calculating the loss of propylene during the regeneration of the propylene guard bed and the liquid-phase dryer is: the loss of propylene during regeneration = the loss of propylene in the unfilled packing part + the loss of propylene in the voids during regeneration + the loss of adsorbed propylene during regeneration.