An apparatus and process for co-producing high-purity carbonyl sulfide and liquid CO2

Abstract

The present invention relates to a device and process for co-producing high-purity carbonyl sulfide and liquid CO2, and relates to the technical field of chemical gas preparation. It includes: a raw gas compressor, a heat exchanger, a rectification column, and a CO2 liquefaction unit; the raw gas compressor is successively connected to the heat exchanger and the rectification column, first compresses and boosts the regenerated tail gas after desulfurization, then enters the rectification column for rectification after heat exchange and temperature reduction through the heat exchanger, and high-purity carbonyl sulfide products are drawn from the bottom of the rectification column; the top of the rectification column is successively connected to the heat exchanger and the CO2 liquefaction unit through pipelines, the gas discharged from the top of the rectification column is reheated through the heat exchanger and then sent to the CO2 liquefaction unit to produce liquid CO2, a part of the liquid CO2 is sent to the liquid CO2 product pipe for storage, and a part of the liquid CO2 is sent to the rectification column for rectification. The present invention separates and produces high-purity carbonyl sulfide from desulfurized regenerated gas and co-produces liquid CO2 products. The entire process flow is reasonably designed, the device structure is simple, and the operation and use are convenient.

Description

Technical Field

[0001] The present invention relates to the technical field of chemical gas preparation, and particularly to a device and process for co-producing high-purity carbonyl sulfide and liquid CO2. Background Art

[0002] Carbonyl sulfide (chemical formula: COS), also known as carbon oxysulfide and carbonyl sulfide, is an important raw material gas for pesticides, pharmaceuticals and other organic syntheses, and can also be used as an important grain fumigant and petrochemical standard gas raw material. With the rapid development of semiconductor very large scale integrated circuits and memory chips, high-purity carbonyl sulfide is widely used in the etching process of line miniaturization in the field of 12-inch integrated circuit semiconductor technology. Its etching effect in dry etching is very obvious, replacing fluoride etching gas that is difficult to degrade and has a greenhouse effect. With the increasing attention of governments around the world to environmental protection, carbonyl sulfide as a raw and auxiliary material gas for industries such as electronic chip manufacturing, photovoltaic, and LED will receive more and more attention; at the same time, in the petrochemical industry, carbonyl sulfide is used as a calibration gas and standard gas for on-line instruments, and can also be used as a supercritical solvent. It can be predicted that its demand will show a rapid growth trend in the next few years.

[0003] There are many synthesis processes for carbonyl sulfide, mainly including carbon monoxide method, urea method, potassium thiocyanate method, ammonium thiocyanate method, etc., such as the carbonyl sulfide synthesis methods disclosed in patents with patent publication numbers CN103328379A, CN1774396A, CN102674349A, and CN101973547A. The reaction rate of the carbon monoxide method is slow, the product has many impurities and low purity. While processes such as the urea method, potassium thiocyanate method, and ammonium thiocyanate method have a small production scale and high purification difficulty.

[0004] Therefore, how to provide a device and process for co-producing high-purity carbonyl sulfide and liquid CO2 has become an urgent technical problem for those skilled in the art to solve. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and propose a device and process for co-producing high-purity carbonyl sulfide and liquid CO2.

[0006] To achieve the above object, the present invention provides a device for co-producing high-purity carbonyl sulfide and liquid CO2, including: a raw material gas compressor, a heat exchanger, a rectification column, and a CO2 liquefaction unit;

[0007] The raw gas compressor is connected to the heat exchanger and the distillation column in sequence through pipelines. The regenerated tail gas after desulfurization is first compressed and pressurized, then cooled by heat exchange in the heat exchanger and enters the distillation column for rectification. High-purity carbonyl sulfide products are drawn from the bottom of the distillation column; the top of the distillation column is connected to the heat exchanger and the CO2 liquefaction unit in sequence through pipelines. The gas discharged from the top of the distillation column is reheated by the heat exchanger and then sent to the CO2 liquefaction unit to produce liquid CO2. Part of the liquid CO2 is sent to the liquid CO2 product pipeline for storage, and part of the liquid CO2 is sent to the distillation column for rectification.

[0008] Furthermore, when the liquid CO2 is sent to the distillation column for rectification, it first exchanges heat through the heat exchanger to provide the cooling capacity required for cooling the raw gas, and then serves as the washing liquid of the distillation column to wash down the carbonyl sulfide in the regenerated tail gas.

[0009] Furthermore, it further includes a purification unit, which is located between the raw gas compressor and the heat exchanger and is used to dehydrate and dry the regenerated tail gas after compression and pressurization.

[0010] Furthermore, it further includes a cooler. The high-purity carbonyl sulfide product drawn from the bottom of the distillation column is cooled by the cooler and then sent out for storage.

[0011] Furthermore, the purification unit includes a bag filter, a fan, a purification box and a partition. The partition is vertically arranged in the purification box, separating the purification box into a filtration chamber and a drying chamber. The raw gas compressor is connected to the air inlet of the bag filter through a pipeline. The air outlet of the bag filter is connected to the filtration chamber through a fan. A nanofiber filter layer is detachably installed at the bottom of the filtration chamber. A waterproof breathable membrane and a drying layer are sequentially arranged obliquely from bottom to top in the drying chamber. An air outlet is arranged at the top of one side of the drying chamber. An inclined surface is arranged at the bottom end inside the purification box, and a water outlet is arranged at the low point of the inclined surface.

[0012] Furthermore, the heat source of the reboiler at the bottom of the distillation column is compressed high-temperature gas or low-pressure steam.

[0013] Furthermore, the heat exchanger adopts a plate-fin heat exchanger or a multi-channel spiral-wound heat exchanger.

[0014] Furthermore, the heat exchanger and the distillation column are insulated with rubber and plastic, or are placed in a cold box together and insulated with perlite sand.

[0015] A process for co-producing high-purity carbonyl sulfide and liquid CO2 is realized by using the device for co-producing high-purity carbonyl sulfide and liquid CO2 described in any one of the above, and includes:

[0016] After the regenerated tail gas passes through the desulfurization unit and is compressed and boosted by the raw material gas compressor, it enters the purification unit to remove moisture. The dried compressed gas is cooled by a heat exchanger and then enters the distillation column for distillation. High-purity carbonyl sulfide product is drawn from the bottom of the column, cooled by a cooler, and then sent out for storage. The gas discharged from the top of the distillation column is reheated by the heat exchanger and then sent to the CO2 liquefaction unit to produce liquid CO2. Part of the liquid CO2 is sent to the liquid CO2 product pipeline for storage, and part of the liquid CO2 is sent to the distillation column for distillation.

[0017] The beneficial effects of the present invention are as follows:

[0018] The present invention provides a device and process for co-producing high-purity carbonyl sulfide and liquid CO2, which separates the carbonyl sulfide contained in the tail gas to make high-purity carbonyl sulfide, and at the same time liquefies the CO2 in the tail gas to make liquid CO2 products. While solving the problem of the up-to-standard discharge of the regenerated tail gas, the carbonyl sulfide in the waste gas is converted into products, bringing good economic benefits. The entire process flow is reasonably designed, the device structure is simple, and it is convenient to operate and use. Description of the Drawings

[0019] Figure 1 is the structural block diagram of the present invention;

[0020] Figure 2 is the structural schematic diagram of the purification unit of the present invention.

[0021] Among them, in the figure:

[0022] 1 - Bag dust removal; 2 - Fan; 3 - Purification box; 4 - Partition board; 5 - Filter chamber; 6 - Drying chamber; 7 - Nanofiber filter layer; 8 - Waterproof and breathable membrane; 9 - Drying layer; 10 - Inclined plane. Detailed Embodiments

[0023] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0024] It should be noted that the terms "first", "second", etc. in the description, claims and the above-mentioned drawings of this application 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 the data used in this way can be interchanged under appropriate circumstances, so as to implement the embodiments of this application described here. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes 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 that are not clearly listed or are inherent to these processes, methods, products or devices.

[0025] In this application, the orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", "front", "rear", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "lateral", "longitudinal", etc. is based on the orientation or positional relationship shown in the drawings. These terms are mainly used to better describe this application and its embodiments, and are not used to limit that the indicated device, element or component must have a specific orientation, or be constructed and operated in a specific orientation.

[0026] Moreover, in addition to being able to represent the orientation or positional relationship, some of the above terms may also be used to represent other meanings. For example, the term "upper" may also be used to represent a certain attachment relationship or connection relationship in some cases. For those of ordinary skill in the art, the specific meanings of these terms in this application can be understood according to specific circumstances.

[0027] In addition, the terms "install", "set", "be provided with", "connect", "be connected", "be sleeved" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or there can also be internal communication between two devices, elements or components. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0028] Considering that carbonyl sulfide is contained in the regeneration tail gas of the desulfurization device, the present invention develops a high-purity carbonyl sulfide device and process with reasonable process, convenient operation and stable production, separates the contained carbonyl sulfide to make high-purity carbonyl sulfide, and at the same time liquefies the CO2 in the tail gas to make liquid CO2 products, bringing good economic benefits while solving the problem of up-to-standard discharge of the regeneration tail gas and converting the carbonyl sulfide in the waste gas into products.

[0029] Reference Figure 1, the present invention provides a device for co-producing high-purity carbonyl sulfide and liquid CO2, comprising: a raw gas compressor, a heat exchanger, a distillation column, a CO2 liquefaction unit, a purification unit and a cooler;

[0030] The raw gas compressor is connected in sequence through pipelines to the purification unit, the heat exchanger and the distillation column. The atmospheric pressure and normal temperature regeneration tail gas from the desulfurization device is compressed and boosted to 2.8 - 3.5 MPa by the raw gas compressor and then enters the purification unit to remove moisture, reducing its dew point to below -40°C. The dried compressed gas is cooled to -45 to -30°C through heat exchange in the heat exchanger and then enters the distillation column for rectification. Carbonyl sulfide products with a purity of ≥99.9% are drawn from the bottom of the column, cooled by the cooler and then sent out for storage. The top of the distillation column is connected in sequence through pipelines to the heat exchanger and the CO2 liquefaction unit. The gas discharged from the top of the distillation column is reheated through the heat exchanger and then sent to the CO2 liquefaction unit to produce liquid CO2. Part of the liquid CO2 is sent to the liquid CO2 product pipeline for storage, and part of the liquid CO2 is sent to the distillation column for rectification as the top washing liquid.

[0031] In this embodiment, the liquid CO2 is sent to the distillation column for rectification. First, it provides the cooling capacity required for the raw gas to cool down through heat exchange in the heat exchanger, and then as the washing liquid of the distillation column, it washes down the carbonyl sulfide in the regeneration tail gas.

[0032] The present invention further includes valves provided on each pipeline to control the opening and closing through the valves.

[0033] Reference Figure 2 , the purification unit includes a bag filter 1, a fan 2, a purification box 3 and a partition 4. The partition 4 is vertically arranged in the purification box 3, separating the purification box 3 into a filtration chamber 5 and a drying chamber 6. The raw gas compressor is connected through a pipeline to the air inlet of the bag filter 1. The air outlet of the bag filter 1 is connected to the filtration chamber 5 through the fan 2. A nanofiber filter layer 7 is detachably installed at the bottom of the filtration chamber 5. In the drying chamber 6, a waterproof breathable membrane 8 and a drying layer 9 are sequentially arranged obliquely from bottom to top. An air outlet is provided at the top end of one side of the drying chamber 6. A slope 10 is arranged at the bottom end inside the purification box 3, and a water outlet is arranged at the low point of the slope 10. Among them, the waterproof breathable membrane 8 can adopt a TPU membrane, etc.; the drying layer can be filled and made with raw materials such as limestone. Most of the gas impurities can be filtered through the bag filter, the nanofiber filter layer 7 can remove fine impurities, the water mist in the gas can be removed through the obliquely arranged waterproof breathable membrane 8, and it is convenient for the water to flow down in a stream. The arrangement of the slope 10 is convenient for draining water, and the water vapor can be removed through the drying layer 9 to achieve gas drying.

[0034] In this embodiment, the heat source of the reboiler at the bottom of the distillation column adopts the compressed high-temperature gas, or adopts low-pressure steam as the heat source.

[0035] In this embodiment, the heat exchanger is a plate-fin heat exchanger or a multi-channel wound tube heat exchanger.

[0036] In this embodiment, the heat exchanger and the distillation column are insulated with rubber and plastic, or are placed in a cold box and insulated with perlite sand.

[0037] The present invention also provides a process for co-producing high-purity carbonyl sulfide and liquid CO2, comprising:

[0038] The regeneration tail gas from the desulfurization device is compressed and boosted by a raw material gas compressor, and then enters the purification unit to remove moisture; the dried compressed gas is cooled by heat exchange in a heat exchanger and then enters the distillation column for rectification. High-purity carbonyl sulfide product is withdrawn from the bottom of the column, and after being cooled by a cooler, it is sent out for storage; the gas discharged from the top of the distillation column is reheated in the heat exchanger and then sent to the CO2 liquefaction unit to produce liquid CO2. A part of the liquid CO2 is sent to the liquid CO2 product pipe for storage, and a part of the liquid CO2 is sent to the distillation column for rectification.

[0039] The present invention provides a device and a process for co-producing high-purity carbonyl sulfide and liquid CO2, which separates the carbonyl sulfide contained in the tail gas into high-purity carbonyl sulfide, and at the same time liquefies the CO2 in the tail gas into liquid CO2 product. While solving the problem of up-to-standard discharge of the regeneration tail gas, the carbonyl sulfide in the waste gas is converted into a product, bringing good economic benefits. The whole process flow is reasonably designed, the device structure is simple, and the operation and use are convenient.

[0040] The above is only a preferred embodiment of the present invention, and does not impose any limitation on the technical scope of the present invention. Therefore, any minor modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. An apparatus for co-producing high-purity carbonyl sulfide and liquid CO2, characterized in that, Including: Raw gas compressor, heat exchanger, distillation column and CO2 liquefaction unit; The raw gas compressor is connected to the heat exchanger and the distillation column in sequence through pipelines. The atmospheric pressure and normal temperature regeneration tail gas from the desulfurization device is compressed and boosted to 2.8 - 3.5 MPa by the raw gas compressor, and then enters the purification unit to remove moisture, reducing its dew point to below -40 °C. The dried compressed gas is cooled to -45 - -30 °C through heat exchange in the heat exchanger and then enters the distillation column for rectification. Carbonyl sulfide products with a purity of ≥99.9% are drawn from the bottom of the column. The top of the distillation column is connected to the heat exchanger and the CO2 liquefaction unit in sequence through pipelines. The gas discharged from the top of the distillation column is reheated through the heat exchanger and then sent to the CO2 liquefaction unit to produce liquid CO2. Part of the liquid CO2 is sent to the liquid CO2 product pipeline for storage, and part of the liquid CO2 is sent to the distillation column for rectification; It also includes a purification unit, which is located between the raw gas compressor and the heat exchanger and is used for dehydrating and drying the regenerated tail gas after compression and boosting; The purification unit includes a bag filter, a fan, a purification box and a partition. The partition is vertically arranged in the purification box, dividing the purification box into a filtration chamber and a drying chamber. The raw gas compressor is connected to the air inlet of the bag filter through a pipeline, the air outlet of the bag filter is connected to the filtration chamber through a fan, a nanofiber filter layer is detachably installed at the bottom of the filtration chamber, a waterproof and breathable membrane and a drying layer are sequentially arranged obliquely from bottom to top in the drying chamber, an air outlet is arranged at the top of one side of the drying chamber, and an inclined surface is arranged at the bottom end inside the purification box, and a water outlet is arranged at the low point of the inclined surface; The liquid CO2 is sent to the distillation column for rectification. First, it exchanges heat through the heat exchanger to provide the cold energy required for cooling the raw gas, and then it is used as the washing liquid of the distillation column to wash down the carbonyl sulfide in the regenerated tail gas; It also includes a cooler. The high-purity carbonyl sulfide product drawn from the bottom of the distillation column is cooled by the cooler and then sent out for storage; The heat source of the reboiler at the bottom of the distillation column is compressed high-temperature gas or low-pressure steam; The heat exchanger adopts a plate-fin heat exchanger or a multi-channel wound tube heat exchanger; The heat exchanger and the distillation column are insulated with rubber and plastic, or are placed in a cold box and insulated with perlite; The process for co-producing high-purity carbonyl sulfide and liquid CO2 includes: The regeneration tail gas passing through the desulfurization device is compressed and boosted by the raw gas compressor and then enters the purification unit to remove moisture. The dried compressed gas is cooled through heat exchange in the heat exchanger and then enters the distillation column for rectification. High-purity carbonyl sulfide products are drawn from the bottom of the column, cooled by the cooler and then sent out for storage. The gas discharged from the top of the distillation column is reheated through the heat exchanger and then sent to the CO2 liquefaction unit to produce liquid CO2. Part of the liquid CO2 is sent to the liquid CO2 product pipeline for storage, and part of the liquid CO2 is sent to the distillation column for rectification.

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