WO2023240777A1 - 一种复合吸附剂床及其应用 - Google Patents

一种复合吸附剂床及其应用 Download PDF

Info

Publication number
WO2023240777A1
WO2023240777A1 PCT/CN2022/111036 CN2022111036W WO2023240777A1 WO 2023240777 A1 WO2023240777 A1 WO 2023240777A1 CN 2022111036 W CN2022111036 W CN 2022111036W WO 2023240777 A1 WO2023240777 A1 WO 2023240777A1
Authority
WO
WIPO (PCT)
Prior art keywords
molecular sieve
adsorbent bed
composite adsorbent
lsx
layer
Prior art date
Application number
PCT/CN2022/111036
Other languages
English (en)
French (fr)
Inventor
张舟
梁曙光
涂巍巍
沈红宝
陈莎
蒋化
李世刚
耿云峰
唐伟
Original Assignee
北京北大先锋科技股份有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 北京北大先锋科技股份有限公司 filed Critical 北京北大先锋科技股份有限公司
Publication of WO2023240777A1 publication Critical patent/WO2023240777A1/zh

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/02—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography
    • B01D53/04—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography with stationary adsorbents
    • B01D53/047—Pressure swing adsorption
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
    • B01J20/02—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material
    • B01J20/10—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising silica or silicate
    • B01J20/16—Alumino-silicates
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B13/00—Oxygen; Ozone; Oxides or hydroxides in general
    • C01B13/02—Preparation of oxygen
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2256/00—Main component in the product gas stream after treatment
    • B01D2256/12—Oxygen

Definitions

  • the invention belongs to the field of gas separation technology, and specifically relates to an adsorbent bed used in a pressure swing adsorption oxygen production process.
  • Adsorbent is the basis of pressure swing adsorption separation.
  • the performance of adsorbent determines the adsorption separation effect, equipment investment and separation economy.
  • the adsorbents used in the pressure swing adsorption oxygen production process are mostly zeolite molecular sieves. Initially, 5A and 13X molecular sieves were mainly used. However, due to the small amount of nitrogen adsorbed and the low nitrogen and oxygen separation coefficient, the development of pressure swing adsorption oxygen production technology was restricted. . With in-depth research on the modification of oxygen-generating adsorbents, in the 1990s, lithium molecular sieves with larger nitrogen adsorption capacity and higher nitrogen-oxygen separation coefficient began to be gradually used in pressure swing adsorption oxygen generation processes.
  • Li-LSX molecular sieve prepared by Li + exchange with an LSX molecular sieve with a Si/Al ratio less than 1.2 is currently the most ideal pressure swing adsorption oxygen production adsorbent.
  • the nitrogen and oxygen separation coefficient can reach 9.68.
  • people have tried to introduce other hetero ions into Li-LSX molecular sieves, such as Li-Ag-LSX molecular sieve (CN102784617B), Li-Ca-LSX molecular sieve (CN103539150A), etc. Even lithium ions are completely replaced by other cations.
  • US5152813A discloses the preparation method of Sr-LSX molecular sieve, and shows that its nitrogen adsorption capacity under normal temperature and pressure is 0.98mmol/g, and the nitrogen-oxygen separation coefficient can reach 5.85.
  • US4481018A and US4557736A also disclose the preparation method of Sr-LSX molecular sieve, as well as the nitrogen and oxygen adsorption capacity, selectivity, etc. However, the adsorption capacity and selectivity of Sr-LSX molecular sieve are still inferior to Li-LSX molecular sieve.
  • One object of the present invention is to provide a composite adsorbent bed including a first molecular sieve layer and a second molecular sieve layer, which can increase the yield of pressure swing adsorption oxygen production and reduce energy consumption.
  • the composite adsorbent bed of the present invention includes a first molecular sieve layer and a second molecular sieve layer; wherein, the first molecular sieve layer includes a first molecular sieve, and the second molecular sieve layer includes a second molecular sieve; the first molecular sieve includes Sr, and the second molecular sieve layer includes Sr.
  • the molecular sieve contains Li; along the direction from the feed end to the product end of the composite adsorbent bed, the first molecular sieve layer is first provided in the composite adsorbent bed, and then the second molecular sieve layer is provided. In the pressure swing adsorption oxygen production process, the composite adsorbent bed can achieve lower energy consumption, lower cost, and higher yield than an adsorbent bed using Li-LSX molecular sieve alone.
  • Another object of the present invention is to provide a pressure swing adsorption system, which includes the above composite adsorbent bed.
  • Another object of the present invention is to provide a pressure swing adsorption oxygen production method, which adopts the above pressure swing adsorption system.
  • the inventor of the present invention unexpectedly discovered that although the nitrogen adsorption capacity of Sr-LSX molecular sieve is slightly smaller than that of Li-LSX molecular sieve ( Figure 1), its bulk density is larger than that of Li-LSX molecular sieve, such as the bulk density of Sr-LSX.
  • Li-LSX molecular sieve It is 1.19 times that of Li-LSX molecular sieve, so that when it replaces Li-LSX molecular sieve in medium volume in the adsorbent bed, it can improve the device performance (such as: low energy consumption, high yield); moreover, the oxygen content of Sr-LSX molecular sieve
  • the adsorption capacity is greater than that of the Li-LSX molecular sieve, and as the pressure increases, the difference in oxygen adsorption capacity between it and the Li-LSX molecular sieve becomes larger ( Figure 2).
  • the Sr-LSX molecular sieve is used for oxygen at the inlet end of the adsorbent bed. A lower partial pressure will be more conducive to reducing oxygen loss.
  • the Sr-LSX molecular sieve is also used at the product end of the adsorbent bed with a large oxygen partial pressure, due to the dynamic effects of the Sr-LSX molecular sieve on oxygen Excessive adsorption capacity will lead to a decrease in the yield of product oxygen.
  • the inventor of the present invention further discovered that the above shortcomings can be overcome by installing a Li-LSX molecular sieve with a smaller dynamic adsorption capacity for oxygen at the product end.
  • a composite adsorbent bed which includes a first molecular sieve layer and a second molecular sieve layer, wherein the first molecular sieve layer includes a first molecular sieve, and the second molecular sieve layer includes a second molecular sieve; the first molecular sieve includes Sr, and the third molecular sieve layer includes Sr.
  • the two molecular sieves include Li; along the direction from the feed end to the product end of the composite adsorbent bed, the first molecular sieve layer is first provided, and then the second molecular sieve layer is provided.
  • the first molecular sieve layer is disposed in the feed end region of the composite adsorbent bed; and/or the second molecular sieve layer is disposed in the product end region of the composite adsorbent bed.
  • first molecular sieve layer and a second molecular sieve layer are provided in the composite adsorbent bed, wherein the first molecular sieve layer is provided in the feed end area of the composite adsorbent bed, and the second molecular sieve layer is provided in in the product end region of the composite adsorbent bed.
  • the first molecular sieve layer includes Sr-LSX molecular sieve; and/or, the second molecular sieve layer includes Li-LSX molecular sieve.
  • the first molecular sieve layer is a Sr-LSX molecular sieve layer
  • the second molecular sieve layer is a Li-LSX molecular sieve
  • the ratio of the bulk density of the first molecular sieve to the second molecular sieve is greater than 1, more preferably greater than 1.15.
  • the first molecular sieve is Sr-LSX molecular sieve
  • the second molecular sieve is Li-LSX molecular sieve
  • the volume ratio of the first molecular sieve layer to the second molecular sieve layer is 70:30-20:80; more preferably, the volume ratio of the first molecular sieve layer to the second molecular sieve layer is 60:40-30:70 .
  • the available ion sites in the first molecular sieve are occupied by Sr, and 0% to 40% of the available ion sites are occupied by second ions; preferably, the second ions are Ca and/or Ba.
  • 0% to 40% of the available ion sites in the first molecular sieve are occupied by Ca, and 100% to 60% of the available ion sites are occupied by Sr; preferably, 100% of the available ion sites in the first molecular sieve are occupied. The point is occupied by Sr.
  • the composite adsorbent bed is also provided with one or more layers of a 13X molecular sieve layer, an activated alumina layer, a silica gel layer, and a 5A molecular sieve layer.
  • the composite adsorbent bed is provided with only a Sr-LSX molecular sieve layer and a Li-LSX molecular sieve layer; the Sr-LSX molecular sieve layer and the Li-LSX molecular sieve layer have the above characteristics.
  • the first molecular sieve layer and the second molecular sieve layer produce good synergy, which can achieve lower energy consumption and cost and higher yield.
  • the positions of Sr-LSX molecular sieve and Li-LSX molecular sieve are exchanged in the adsorbent bed, the effect will be poor.
  • the volume ratio of the first molecular sieve layer to the second molecular sieve layer is 70:30-20:80, preferably 60:40-30:70.
  • 0% to 40% of the available ion sites in the first molecular sieve are occupied by second ions (such as Ca and/or Ba), and 100% to 60% of the available ion sites are occupied by Sr; preferably, the third 0% to 40% of the available ion sites in a molecular sieve are occupied by Ca, and 100% to 60% of the available ion sites are occupied by Sr; further preferably, 100% of the available ion sites in the first molecular sieve are occupied by Sr .
  • the composite adsorbent bed is also provided with one or more layers of a 13X molecular sieve layer, an activated alumina layer, and a silica gel layer; a 13X molecular sieve layer, an activated alumina layer, and a silica gel layer are provided at the feed end to remove ions in the raw material gas. Impurities such as water, carbon dioxide, etc.
  • a pressure swing adsorption system which includes at least two of the above composite adsorbent beds, control valves, compressors and other equipment.
  • a method for producing oxygen by separating air using the above-mentioned pressure swing adsorption system sequentially undergoes an adsorption oxygen production step, an equalizing pressure drop step, a vacuum desorption step, a product gas flushing step, and an equalizing pressure increasing step. , oxygen return step, pressurization step and other seven basic steps.
  • a method for producing oxygen by pressure swing adsorption which realizes producing oxygen from the air through a pressure swing adsorption system.
  • the pressure swing adsorption system includes at least two of the above-mentioned composite adsorbent beds and a plurality of controls for controlling the flow disconnection of the air flow. Valve; the air enters the composite adsorbent bed after being compressed by the compressor; each composite adsorbent bed sequentially undergoes the adsorption oxygen production step, the equalization pressure drop step, the vacuum desorption step, the product gas flushing step, the pressure equalization step, and the oxygen return step.
  • An application of the composite adsorbent bed or the pressure swing adsorption system in gas separation is the application of air to produce oxygen.
  • the Li-LSX type molecular sieve can be: a molecular sieve as described in US5573745A, US5584912A or US5413625A;
  • the Sr-LSX type molecular sieve can be: a molecular sieve as described in US5152813A, US4557736A.
  • the oxygen adsorption capacity of Sr-LSX is greater than that of Li-LSX, and as the pressure increases, the difference between the oxygen adsorption capacity of Sr-LSX and Li-LSX becomes larger. It will be more effective to use it at the lower end of the composite adsorbent bed where the oxygen partial pressure is lower. It is beneficial, otherwise the oxygen yield of the product will decrease due to excessive oxygen adsorption.
  • Adsorption oxygen production step (A) Depending on the scale of oxygen consumption, one or more composite adsorbent beds are selected to introduce air at the same time.
  • the adsorption pressure is selected as 1.3 ⁇ 2bar (absolute pressure), and the optimal selection is 1.4 ⁇ 1.6bar (absolute pressure).
  • the adsorbent in the composite adsorbent bed uses Sr-LSX molecular sieve at the feed end and Li-LSX molecular sieve at the product end.
  • the volume ratio of the Sr-LSX type molecular sieve to the Li-LSX type molecular sieve is 70:30 to 20:80, preferably 60:40 to 30:70.
  • the air is compressed by the compressor and enters from the feed end at the bottom of the composite adsorbent bed.
  • Nitrogen is adsorbed by the adsorbent as an impurity, and the remaining gas is led out from the upper part of the tower as product gas.
  • Oxygen products with purity ranging from 50% to 95% and output ranging from 200Nm 3 /h to 7500Nm 3 /h can be obtained as needed.
  • Equal pressure drop step The composite adsorbent bed that has completed adsorption stops air intake and oxygen production, is connected to other composite adsorbent beds that have completed flushing, and recovers the oxygen in its dead space to other composite adsorbents. in bed.
  • Vacuum desorption step (V) The composite adsorbent bed that has completed the equalization pressure drop stops communicating with other composite adsorbent beds, and is evacuated with a vacuum pump to desorb the nitrogen adsorbed therein.
  • the vacuum pressure is 0.3 ⁇ 0.7bar (absolute pressure), and the optimal selection is 0.4 ⁇ 0.5bar (absolute pressure).
  • Product gas flushing step (PP) Flush the vacuumed composite adsorbent bed with product gas at the same time.
  • the amount of flushing gas is 5% to 20% of the gas production, and the optimal selection is 8% to 12%.
  • the present invention provides a pressure swing adsorption oxygen production method.
  • a pressure swing adsorption system including the composite adsorbent bed to produce oxygen from the air
  • the invention has the advantages of improving the product oxygen recovery rate, reducing investment and operating costs, and improving the process. Simple and versatile. Specifically, the advantages of the present invention include:
  • Figure 1 is the adsorption isotherm of nitrogen in Li-LSX molecular sieves and Sr-LSX molecular sieves at room temperature.
  • Figure 2 is the adsorption isotherm of oxygen in Li-LSX molecular sieve and Sr-LSX molecular sieve at room temperature.
  • Figure 3 is a schematic diagram of a composite adsorbent bed equipped with 13X molecular sieve, Sr-LSX molecular sieve, and Li-LSX molecular sieve.
  • Figure 4 is a schematic diagram of a composite adsorbent bed equipped with Sr-LSX molecular sieve and Li-LSX molecular sieve.
  • the invention provides a pressure swing adsorption oxygen production method, which realizes production of oxygen from the air through a pressure swing adsorption system.
  • the pressure swing adsorption system includes at least two composite devices using Sr-LSX type molecular sieves and Li-LSX type molecular sieves.
  • the adsorbent bed and a plurality of control valves used to control the flow and disconnection of the air flow; the air is compressed by the compressor and enters the composite adsorbent bed, and each composite adsorbent bed is equipped with an adsorbent that can selectively adsorb nitrogen; each composite adsorbent bed is equipped with an adsorbent that can selectively adsorb nitrogen;
  • the composite adsorbent bed sequentially undergoes seven basic steps: adsorption oxygen production step, equalization pressure drop step, vacuum desorption step, product gas flushing step, pressure equalization step, oxygen return step, and pressurization step.
  • the pressure swing adsorption system of the example operates at room temperature and is a system composed of two composite adsorbent beds.
  • the tower diameter of each composite adsorbent bed is 3600mm, and the adsorbent in the tower is loaded.
  • the segment height is 967mm.
  • the timing of a cycle of the system is shown in Table 2. In each period of the adsorption regeneration cycle, each tower of the system is in different working states.
  • the composite adsorbent bed used in Examples 1 to 5 is shown in Figure 4.
  • Sr-LSX molecular sieve is used at the feed end of the composite adsorbent bed
  • Li-LSX molecular sieve is used at the product end.
  • Comparative Example 1 uses only Li-LSX type molecular sieves in the adsorbent bed
  • Comparative Example 2 only uses Sr-LSX type molecular sieves in the adsorbent bed
  • Comparative Example 3 uses Li-LSX type molecular sieves at the feed end of the adsorbent bed.
  • Sr-LSX type molecular sieve is used on its product end.
  • the Sr-LSX type molecular sieve is prepared according to the method described in Example 9 of US5152813A, and has the performance shown in Table It has the performance shown in Example 1 of Table 2 in US5413625A.
  • Examples 1-5 and Comparative Examples 1-3 The only difference between Examples 1-5 and Comparative Examples 1-3 is that the adsorbents shown in Tables 3 and 4 are different, and other process conditions are the same.
  • the volume ratio and operating results of the Sr-LSX type molecular sieve and Li-LSX type molecular sieve are as shown in Table 3 and Table 4.
  • Example 5 when the volume ratio of Sr-LSX type molecular sieve to Li-LSX type molecular sieve in the composite adsorbent bed is 70:30 ⁇ 30:70, compared with Comparative Example 1-2 It has higher yield and lower energy consumption; as shown in Example 5, when the volume ratio of Sr-LSX molecular sieve and Li-LSX molecular sieve in the composite adsorbent bed is 80:20, the yield , the energy consumption is slightly lower than that of Comparative Example 1, but the cost is much lower than Comparative Example 1.
  • the composite adsorbent bed of the present invention obviously has lower investment, energy consumption, and equivalent or higher yield.
  • Using a composite adsorbent bed with a volume ratio of Sr-LSX type molecular sieve to Li-LSX type molecular sieve of 70:30 can achieve lower costs; using a volume ratio of Sr-LSX type molecular sieve to Li-LSX type molecular sieve is 30: 70 composite adsorbent bed can achieve better device performance (such as high yield, low energy consumption).

Landscapes

  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Analytical Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Inorganic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • General Chemical & Material Sciences (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Separation Of Gases By Adsorption (AREA)
  • Solid-Sorbent Or Filter-Aiding Compositions (AREA)

Abstract

一种复合吸附剂床，床内沿进料端至产物端的方向，先设置第一分子筛层，然后设置第二分子筛层，其中，第一分子筛层包括含 Sr的第一分子筛，第二分子筛层包括含 Li的第二分子筛。该复合吸附剂床在变压吸附制氧工艺中的应用。

Description

一种复合吸附剂床及其应用 技术领域
本发明属于气体分离技术领域，具体涉及一种变压吸附制氧工艺中使用的吸附剂床。
背景技术
在当今的生产生活中，不同浓度的氧气广泛应用于各行各业，例如钢铁生产、燃料燃烧供能、废水废气处理、以及航空航天和医疗保健等方面。现在工业上应用最为广泛的制氧方法是深冷法和变压吸附(PSA)法。变压吸附制氧技术工业化应用起源于20世纪70年代，其产品气中氧气纯度在50％～95％之间可调，可满足各行各业的用氧需求，而且工艺简单、运行稳定，投资和运行成本低，被越来越多的需氧企业所青睐。
吸附剂是变压吸附分离的基础，吸附剂的性能决定着吸附分离效果、设备投资和分离的经济性。变压吸附制氧工艺中使用的吸附剂多为沸石分子筛，最初使用的主要是5A和13X分子筛，但由于氮气吸附量较小，氮氧分离系数低，制约了变压吸附制氧技术的发展。随着人们对制氧吸附剂改性的深入研究，20世纪90年代，具有较大氮气吸附容量和较高氮氧分离系数的锂分子筛开始逐步被应用于变压吸附制氧工艺。
大量研究(如US5573745A、US5584912A、US5413625A等)表明，Si/Al比小于1.2的LSX型分子筛经过Li +交换后所制备的Li-LSX型分子筛是当前最为理想的变压吸附制氧吸附剂，其氮氧分离系数可达9.68。但由于锂盐成本较高，人们尝试将别的杂离子引入Li-LSX分子筛中，如Li-Ag-LSX分子筛(CN102784617B)、Li-Ca-LSX分子筛(CN103539150A)等。甚至用别的阳离子完全代替锂离子，如US5152813A公开了Sr-LSX分子筛的制备方法，并给出其常温常压下氮的吸附量为0.98mmol/g，氮氧分离系数可达5.85。US4481018A、US4557736A中也公开了Sr-LSX分子筛的制备方法，及氮、氧吸附量，以及选择性等，但Sr-LSX型分子筛吸附量、选择性仍不如Li-LSX分子筛。
总之，使用Li-LSX分子筛吸附剂床的变压吸附制氧工艺，虽然和以往工艺相比，实现了更高的收率和更低的能耗，但其成本较高，且收率仍需进一步提高，能耗仍需进一步降低。因此，有必要开发一种新的吸附剂床，使其收率高，能耗低，成本低。
发明内容
本发明的一个目的在于提供一种包含第一分子筛层和第二分子筛层的复合吸附剂床，提 高变压吸附制氧的收率，降低能耗。
本发明的复合吸附剂床包含第一分子筛层和第二分子筛层；其中，第一分子筛层包括第一分子筛，第二分子筛层包括第二分子筛；所述第一分子筛包含Sr，所述第二分子筛包含Li；沿所述复合吸附剂床的进料端至产物端的方向，在所述复合吸附剂床内先设置有所述第一分子筛层，然后设置有第二分子筛层。所述复合吸附剂床在变压吸附制氧工艺中，相对于单独使用Li-LSX分子筛的吸附剂床，其可实现更低的能耗，更低的成本，更高的收率。
本发明的另一个目的在于提供一种变压吸附系统，其包括上述复合吸附剂床。
本发明的另一个目的在于提供一种变压吸附制氧的方法，其采用上述变压吸附系统。
本发明的发明人意外发现，Sr-LSX型分子筛的氮气吸附容量虽略小于Li-LSX型分子筛(图1)，但因其堆密度比Li-LSX型分子筛大，如Sr-LSX的堆密度是Li-LSX型分子筛的1.19倍，使得其在吸附剂床中等体积替换Li-LSX型分子筛时，可改善装置性能(如：低能耗，高收率)；而且，Sr-LSX型分子筛的氧气吸附容量大于Li-LSX型分子筛，且随着压力增加其与Li-LSX型分子筛的氧气吸附量之差越大(图2)，将Sr-LSX型分子筛用于吸附剂床的进气端氧气分压较低处会更有利于减少氧气损失。
但如果在吸附剂床中只用Sr-LSX型分子筛，即：将Sr-LSX型分子筛还用在氧分压较大的吸附剂床的产物端，则由于Sr-LSX型分子筛对氧气的动态吸附容量过大而导致产品氧的收率下降。本发明的发明人进一步发现，在产物端装上对氧气动态吸附容量较小的Li-LSX型分子筛，则可克服上述缺点。
基于上述发现，提供如下的技术方案：
一种复合吸附剂床，其包含第一分子筛层和第二分子筛层，其中，第一分子筛层包括第一分子筛，第二分子筛层包括第二分子筛；所述第一分子筛包含Sr，所述第二分子筛包含Li；沿所述复合吸附剂床的进料端至产物端的方向，先设置有所述第一分子筛层，后设置有所述第二分子筛层。
优选，所述第一分子筛层设置于所述复合吸附剂床的进料端区域；和/或，所述第二分子筛层设置于所述复合吸附剂床的产物端区域。
优选，所述复合吸附剂床内只设置第一分子筛层和第二分子筛层，其中，所述第一分子筛层设置于所述复合吸附剂床的进料端区域，所述第二分子筛层设置于所述复合吸附剂床的产物端区域。
优选，所述第一分子筛层包含Sr-LSX分子筛；和/或，所述第二分子筛层包含Li-LSX分 子筛。
更优选，所述第一分子筛层为Sr-LSX分子筛层，和/或，所述第二分子筛层为Li-LSX分子筛。
优选，所述第一分子筛与第二分子筛的堆密度之比大于1，更优选大于1.15。
优选，所述第一分子筛为Sr-LSX分子筛，和/或，所述第二分子筛为Li-LSX分子筛。
优选，所述第一分子筛层与第二分子筛层的体积比为70:30～20:80；更优选，所述第一分子筛层与第二分子筛层的体积比为60:40～30:70。
优选，所述第一分子筛中100％至60％的可用离子位点被Sr占据，0％至40％的可用离子位点被第二离子占据；优选，所述第二离子为Ca和/或Ba。
优选，所述第一分子筛中0％至40％的可用离子位点被Ca占据，100％至60％的可用离子位点被Sr占据；优选，所述第一分子筛中100％的可用离子位点被Sr占据。
优选，所述复合吸附剂床还设置有13X分子筛层、活性氧化铝层、硅胶层、5A分子筛层中的一层或多层。
优选，所述复合吸附剂床仅设置有Sr-LSX型分子筛层和Li-LSX型分子筛层；所述Sr-LSX型分子筛层和Li-LSX型分子筛层具有上述特征。
在所述复合吸附剂床中，第一分子筛层和第二分子筛层产生良好的协同作用，可实现更低的能耗及成本，更高的收率。而如将Sr-LSX型分子筛、Li-LSX型分子筛在吸附剂床中的位置调换，则效果较差。
其中，所述第一分子筛层与第二分子筛层的体积比为70:30～20:80，优选为60:40～30:70。
所述第一分子筛中0％至40％的可用离子位点被第二离子(如Ca和/或Ba)占据，并且100％至60％的可用离子位点被Sr占据；优选，所述第一分子筛中0％至40％的可用离子位点被Ca占据，100％至60％的可用离子位点被Sr占据；进一步优选，所述第一分子筛中100％的可用离子位点被Sr占据。
所述复合吸附剂床还设置有13X分子筛层、活性氧化铝层、硅胶层中的一层或多层；在进料端设置13X分子筛层、活性氧化铝层、硅胶层以除去原料气中的杂质，如水、二氧化碳等。
一种变压吸附系统，其包括至少两个上述复合吸附剂床、控制阀门、压缩机等设备。
一种采用上述变压吸附系统的通过分离空气制备氧气的方法，每个复合吸附剂床都依次经历吸附产氧步骤、均压降步骤、抽真空解吸步骤、产品气冲洗步骤、均压升步骤、回氧步 骤、增压步骤等七个基本步骤。
一种变压吸附制氧的方法，通过变压吸附系统来实现从空气中制取氧气，变压吸附系统包括至少两个上述复合吸附剂床和多个用于控制气流的流通断开的控制阀门；空气在经压缩机压缩进入复合吸附剂床；每个复合吸附剂床都依次经历吸附产氧步骤、均压降步骤、抽真空解吸步骤、产品气冲洗步骤、均压升步骤、回氧步骤、增压步骤等七个基本步骤。上述七个基本步骤中，可以选择步骤的时间设计不同的工艺流程；通过控制阀门的开关设置两塔或多塔工艺步骤的时序步骤，通过两塔或多塔交替使用实现产品氧气的连续生产。
一种采用所述的复合吸附剂床或所述的变压吸附系统在分离气体方面的应用。优选，所述应用为分离空气制备氧气。
优选，所述Li-LSX型分子筛可为：如US5573745A、US5584912A或US5413625A所述分子筛；所述Sr-LSX型分子筛可为：如US5152813A、US4557736A所述分子筛。
通常情况下，100％的可用离子位点被Sr占据的Sr-LSX型分子筛和Li-LSX型分子筛对氮气和氧气在常温常压下的吸附量，以及在复合吸附剂床中的堆密度如表1所示。
表1 常温常压下Sr-LSX型分子筛和Li-LSX型分子筛吸附量对比
Figure PCTCN2022111036-appb-000001
发明人意外发现，Sr-LSX的氮气吸附容量略小于Li-LSX，但因其堆密度是Li-LSX的1.19倍，使得其在复合吸附剂床中等体积替换Li-LSX时，可改善装置性能；Sr-LSX的氧气吸附容量大于Li-LSX，且随着压力增加其与Li-LSX的氧气吸附量之差越大，将其用于复合吸附剂床的下端氧气分压较低处会更有利，否则会因为氧气吸附量过多而造成产品氧收率下降。
本发明的变压吸附循环的具体工艺过程控制如下：
1、吸附产氧步骤(A)：根据用氧规模的不同，选用一个或多个复合吸附剂床同时进空气。吸附压力选择为1.3～2bar(绝压)，优化选择为1.4～1.6bar(绝压)。复合吸附剂床中的吸附剂在进料端使用Sr-LSX型分子筛，在产物端使用Li-LSX型分子筛。所述Sr-LSX型分子筛与Li-LSX型分子筛的体积比为70:30～20:80，优选为60:40～30:70。空气经压缩机压缩，从复合吸附剂床的底部进料端进入，氮气作为杂质被吸附剂吸附，其余气体作为产品气从塔的上部引出。能根据需要得到纯度为50％～95％，产量为200Nm 3/h到7500Nm 3/h的氧气产品。
2、均压降步骤(ED)：吸附完成的复合吸附剂床停止进气与产氧，与别的完成冲洗的复合吸附剂床连通，将其死空间中的氧气回收到别的复合吸附剂床中。
3、抽真空解吸步骤(V)：均压降完成的复合吸附剂床停止与别的复合吸附剂床连通，用真空泵对其进行抽真空，使得其中吸附的氮气得到解吸。抽真空压力为0.3～0.7bar(绝压)，优化选择为0.4～0.5bar(绝压)。
4、产品气冲洗步骤(PP)：在抽真空的复合吸附剂床同时用产品气进行冲洗，冲洗气用量为产气量的5％到20％，优化选择为8％～12％。
5、均压升步骤(ER)：冲洗结束的复合吸附剂床，停止产品气冲洗及抽真空，将其与完成吸附步骤的复合吸附剂床连通，接收其死空间的氧气。
6、回氧步骤(RO)：均压升完成的复合吸附剂床，停止与别的复合吸附剂床连通后，产物端与产品气罐连通，以优化塔内浓度分布。
7、增压步骤(FR)：回氧完成的复合吸附剂床，停止和产品罐连通，开始进气，用空气使得塔压增加到吸附压力。
本发明的有益效果：
本发明提供一种变压吸附制氧的方法，通过使用包含所述复合吸附剂床的变压吸附系统来从空气中制取氧气，具有提高产品氧气回收率，减少投资和运行费用，以及工艺简单、通用性强的特点。具体地，本发明具有的优点包括：
(一)提高氧气的回收率。由于在吸附剂床进料端装一定体积的Sr-LSX型分子筛对氮气的动态吸附容量高于Li-LSX型分子筛，使得其能处理更多的空气得到更多的产品氧气；在产物端装上对氧气动态吸附容量较小的Li-LSX型分子筛，可克服氧气分压大时Sr-LSX型分子筛对氧气动态吸附容量过高的问题。两者协同作用，可提高收率。
(二)降低投资费用和运行费用。由于在吸附剂床进料端装的Sr-LSX型分子筛成本远低于Li-LSX型分子筛，可降低投资费用；同时，氧气回收率的增加，也使得标方纯氧电耗得以降低。
(三)工艺简单，通用性强，可适用于不同产品纯度要求、不同用氧规模的变压吸附制氧项目。
附图说明
图1是常温下氮气在Li-LSX型分子筛以及Sr-LSX分子筛中的吸附等温线。
图2是常温下氧气在Li-LSX型分子筛以及Sr-LSX分子筛中的吸附等温线。
图3是装有13X分子筛、Sr-LSX分子筛，及Li-LSX分子筛的复合吸附剂床示意图。
图4是装有Sr-LSX分子筛及Li-LSX分子筛的复合吸附剂床示意图。
具体实施方式
下面通过实施例进一步描述本发明，但不以任何方式限制本发明的范围。
本发明提供一种变压吸附制氧的方法，通过变压吸附系统来实现从空气中制取氧气，变压吸附系统包括至少两个具有使用Sr-LSX型分子筛和Li-LSX型分子筛的复合吸附剂床和多个用于控制气流的流通断开的控制阀门；空气在经压缩机压缩进入复合吸附剂床，每个复合吸附剂床中均装有能选择吸附氮气的吸附剂；每个复合吸附剂床都依次经历吸附产氧步骤、均压降步骤、抽真空解吸步骤、产品气冲洗步骤、均压升步骤、回氧步骤、增压步骤等七个基本步骤。上述七个基本步骤中，可以选择步骤的时间设计不同的工艺流程；通过控制阀门的开关设置两塔或多塔工艺步骤的时序步骤，通过两塔或多塔交替使用实现产品氧气的连续生产。
以下实施例采用本发明方法进行实施，实施例的变压吸附系统在常温下操作，为由两个复合吸附剂床组成的系统，每个复合吸附剂床塔径为3600mm，塔中吸附剂装填段高度为967mm。系统一个循环的时序如表2所示。在吸附再生循环过程的每一个时段中，系统各塔处于不同的工作状态。
表2 两塔变压吸附制氧工艺的循环时序
复合吸附剂床1 A A ED V V V PP ER RO FR
复合吸附剂床2 V PP ER RO FR A A ED V V
时间(s) 8 6 4 4 4 8 6 4 4 4
实施例1～5所用复合吸附剂床如图4所示。如图4所示，在复合吸附剂床的进料端使用Sr-LSX型分子筛，在其产物端使用Li-LSX型分子筛。比较例1在吸附剂床中仅使用Li-LSX型分子筛，比较例2在吸附剂床中仅使用Sr-LSX型分子筛，比较例3在吸附剂床的进料端使用Li-LSX型分子筛，在其产物端使用Sr-LSX型分子筛。其中，所述Sr-LSX型分子筛按照US5152813A中实施例9所述方法制备，其具有如US5152813A中表X例4所示性能；Li-LSX型分子筛按照US5413625A中实施例3所述方法制备，其具有如US5413625A中表2例1所示性能。
实施例1-5和比较例1-3的差别仅在于如表3和表4所示的吸附剂不同，其他工艺条件 相同。
所述Sr-LSX型分子筛与Li-LSX型分子筛的体积比、运行结果如表3和表4所示。
表3 比较例1-2及实施例1-5的体积比、运行结果
Figure PCTCN2022111036-appb-000002
注：1、投资计算Li-LSX型分子筛价格时，以2022年3月碳酸锂价格为准。
2、以全装Li-LSX(即比较例1)时收率、能耗、投资为1，对收率、能耗、投资进行归一化比较。
表4 比较例3的体积比、运行结果
Figure PCTCN2022111036-appb-000003
注：1、投资计算Li-LSX型分子筛价格时，以2022年3月碳酸锂价格为准。
2、以全装Li-LSX(即比较例1)时收率、能耗、投资为1，对收率、能耗、投资进行归一化比较。
由表3和表4可见，随复合吸附剂床中Sr-LSX型分子筛的比例增大，装置投资成本下降。如表4所示，比较例3中所述复合吸附剂床的进料端使用Li-LSX型分子筛，产物端使用Sr-LSX型分子筛(体积比为50:50)，其收率最低，能耗最高，运行效果远差于与之平行比较的实施例2。如表3中比较例2所示，其收率低于实施例1-5，而能耗却高于实施例1-5。如表3中实施例1-4所示，当复合吸附剂床中Sr-LSX型分子筛与Li-LSX型分子筛的体积比为70:30～30:70时，相比于比较例1-2具有较高的收率，以及较低的能耗；如实施例5所示，当 复合吸附剂床中Sr-LSX型分子筛与Li-LSX型分子筛的体积比为80:20时，其收率、能耗稍逊于比较例1，但成本却远低于比较例1。
由此可见，本发明所述复合吸附剂床明显具有较低的投资、能耗，以及相当或更高的收率。使用Sr-LSX型分子筛与Li-LSX型分子筛的体积比为70:30的复合吸附剂床，可实现更低的成本；使用Sr-LSX型分子筛与Li-LSX型分子筛的体积比为30:70的复合吸附剂床，可获得更优的装置性能(如，高收率，低能耗)。
需要注意的是，公布实施例的目的在于帮助进一步理解本发明，但是本领域的技术人员可以理解：在不脱离本发明及所附权利要求的精神和范围内，各种替换和修改都是可能的。因此，本发明不应局限于实施例所公开的内容，本发明要求保护的范围以权利要求书界定的范围为准。

Claims (10)

  1. 一种复合吸附剂床，其特征在于，所述复合吸附剂床包含第一分子筛层和第二分子筛层；其中，第一分子筛层包括第一分子筛，第二分子筛层包括第二分子筛；所述第一分子筛包含Sr，所述第二分子筛包含Li；沿所述复合吸附剂床的进料端至产物端的方向，在所述复合吸附剂床内先设置有所述第一分子筛层，然后设置有第二分子筛层。
  2. 根据权利要求1所述的复合吸附剂床，其特征在于，所述第一分子筛层设置于所述复合吸附剂床的进料端区域；和/或，所述第二分子筛层设置于所述复合吸附剂床的产物端区域。
  3. 根据权利要求1所述的复合吸附剂床，其特征在于，所述复合吸附剂床内只设置有所述第一分子筛层和所述第二分子筛层。
  4. 根据权利要求1-3任意一项所述的复合吸附剂床，其特征在于，所述第一分子筛层包含Sr-LSX分子筛；和/或，所述第二分子筛层包含Li-LSX分子筛。
  5. 根据权利要求4所述的复合吸附剂床，其特征在于，所述第一分子筛中100％至60％的可用离子位点被Sr占据，0％至40％的可用离子位点被第二离子占据，所述第二离子为Ca和/或Ba。
  6. 根据权利要求1所述的复合吸附剂床，其特征在于，所述第一分子筛与第二分子筛的堆密度之比大于1；所述第一分子筛为Sr-LSX分子筛，和/或，所述第二分子筛为Li-LSX分子筛。
  7. 根据权利要求1所述的复合吸附剂床，其特征在于，所述第一分子筛层与第二分子筛层的体积比为70:30～20:80，优选为60:40～30:70。
  8. 根据权利要求1所述的复合吸附剂床，其特征在于，所述复合吸附剂床还设置有13X分子筛层、活性氧化铝层、硅胶层中的一层或多层。
  9. 一种变压吸附系统，其特征在于，所述变压吸附系统包括至少两个如权利要求1-8任意一项所述的复合吸附剂床。
  10. 权利要求1-8任意一项所述的复合吸附剂床或权利要求9所述的变压吸附系统在气体分离中的应用。
PCT/CN2022/111036 2022-06-16 2022-08-09 一种复合吸附剂床及其应用 WO2023240777A1 (zh)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN202210677977.1 2022-06-16
CN202210677977.1A CN117282224A (zh) 2022-06-16 2022-06-16 一种复合吸附剂床及其应用

Publications (1)

Publication Number Publication Date
WO2023240777A1 true WO2023240777A1 (zh) 2023-12-21

Family

ID=89193042

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2022/111036 WO2023240777A1 (zh) 2022-06-16 2022-08-09 一种复合吸附剂床及其应用

Country Status (2)

Country Link
CN (1) CN117282224A (zh)
WO (1) WO2023240777A1 (zh)

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4557736A (en) * 1984-10-29 1985-12-10 Air Products And Chemicals, Inc. Binary ion exchanged type X zeolite adsorbent
CN1073119A (zh) * 1991-12-11 1993-06-16 普拉塞尔技术有限公司 用于压力摇摆吸附操作的改进的吸附床
CN1182634A (zh) * 1996-09-06 1998-05-27 液体空气乔治洛德方法利用和研究有限公司 含氧与氮的气体混合物的分离方法
CN1207327A (zh) * 1997-04-17 1999-02-10 普拉塞尔技术有限公司 变压吸附进行气体分离的多层吸附床
CN101301999A (zh) * 2008-06-25 2008-11-12 天津大学 从空气中富集氧气的方法
CN108862303A (zh) * 2018-07-04 2018-11-23 洛阳建龙微纳新材料股份有限公司 一种碱土阳离子Sr-LSX分子筛及其制备方法和应用
CN110980652A (zh) * 2019-12-29 2020-04-10 广西珂深威医疗科技有限公司 一种基于分子筛分层填充的制氧系统

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4557736A (en) * 1984-10-29 1985-12-10 Air Products And Chemicals, Inc. Binary ion exchanged type X zeolite adsorbent
CN1073119A (zh) * 1991-12-11 1993-06-16 普拉塞尔技术有限公司 用于压力摇摆吸附操作的改进的吸附床
CN1182634A (zh) * 1996-09-06 1998-05-27 液体空气乔治洛德方法利用和研究有限公司 含氧与氮的气体混合物的分离方法
CN1207327A (zh) * 1997-04-17 1999-02-10 普拉塞尔技术有限公司 变压吸附进行气体分离的多层吸附床
CN101301999A (zh) * 2008-06-25 2008-11-12 天津大学 从空气中富集氧气的方法
CN108862303A (zh) * 2018-07-04 2018-11-23 洛阳建龙微纳新材料股份有限公司 一种碱土阳离子Sr-LSX分子筛及其制备方法和应用
CN110980652A (zh) * 2019-12-29 2020-04-10 广西珂深威医疗科技有限公司 一种基于分子筛分层填充的制氧系统

Also Published As

Publication number Publication date
CN117282224A (zh) 2023-12-26

Similar Documents

Publication Publication Date Title
CN107789949B (zh) 一种负压变压吸附的气体分离方法
CN210340328U (zh) 一种一体式连续制氧制氮装置
CN104058371A (zh) 变压吸附制气系统及其方法
CN101301559A (zh) 变压吸附工艺及装置
CN109319740A (zh) 一种提高吸附剂生产率的变压吸附制氧系统
CN110394027A (zh) 大规模变压吸附与深冷分离耦合的梯级空分工艺
CN102049170B (zh) 一种vpsa空气分离制富氧流程
CN101049911A (zh) 六塔吸附制氧方法
CN209957384U (zh) 一体式吸附制氮装置
CN111204712A (zh) 一种变压吸附气体分离提纯氢气系统及其分离提纯方法
CN201930684U (zh) 氧氩混合气非深冷变压吸附分离装置
CN214528139U (zh) 一种节能型制氧装置
CN220214437U (zh) 一种低能耗的psa空分制氮装置
CN110394026A (zh) 大规模变压吸附梯级空气分离装置
WO2023240777A1 (zh) 一种复合吸附剂床及其应用
CN209302476U (zh) 一种温压协同气体吸附分离提纯系统
CN208471537U (zh) 一种回收粗氩气再提纯装置
CN1228128C (zh) 一种适于高海拔地区用的变压吸附制氧装置
US20220168683A1 (en) Energy-saving process system for purifying and recycling oxygen from high-temperature oxygen-enriched flue gas and process thereof
CN216259894U (zh) 一种氯化氢净化及提纯系统
CN202185250U (zh) 一种空分设备纯化系统
CN211946282U (zh) 一种多塔循环变压吸附制氮的装置
CN219682138U (zh) 一种富氧、纯氮和压缩空气一体化供给装置
CN2647413Y (zh) 变压吸附氮气设备
CN218421902U (zh) 一种氧分子筛空氮分离装置

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 22946450

Country of ref document: EP

Kind code of ref document: A1