A single layer process independent modular multi-layer counter current rectification or evaporation process

Abstract

The present application relates to the technical field of chemical separation and evaporation heat exchange, and particularly relates to a single-layer process independent modular multi-layer countercurrent rectification or evaporation process. The process is implemented by a device composed of at least one standardized tower body unit vertically modularized, and core steps include that a single-layer tower body unit independently completes a rectification or evaporation full-process closed loop, gas-liquid two-phase countercurrent directional transportation, gas-phase product layering independent discharge, and linear regulation of production capacity by increasing or decreasing the number of tower body units. The present application solves the core pain points of traditional process single-layer level without complete process capacity, strong coupling between levels, limited production capacity expansion, low mass transfer efficiency and high operation and maintenance difficulty, has the advantages of single-layer process independence, flexible production capacity regulation, high mass and heat transfer efficiency, wide adaptability and low operation and maintenance cost, and can be widely applied to various chemical separation and evaporation heat exchange processes such as ammonia water separation, wastewater evaporation, organic solvent recovery, traditional Chinese medicine concentration and multi-component rectification.

Description

Technical Field

[0001] This invention relates to the field of chemical separation and evaporation heat exchange technology, specifically to a modular multilayer countercurrent distillation or evaporation process with independent single-layer technology. Background Technology

[0002] Distillation and evaporation are core unit operations in industries such as chemical engineering, pharmaceuticals, environmental protection, and food processing. Distillation columns and evaporation columns are the core equipment for achieving these operations. Currently, the implementation of distillation and evaporation processes in the industry generally relies on column structures with integrated process structures. Regardless of whether the column body is circular or polygonal, there are inherent technical defects that cannot be overcome, as follows: Single-level structures lack independent and complete process capabilities, and the processes between levels are strongly coupled: A single level in a traditional monolithic tower is merely a segment of the overall process (such as a single tray or a single packing layer). It cannot independently complete a complete distillation or evaporation process involving liquid film formation, countercurrent heat exchange, gas-liquid separation, and gas phase discharge. The separation target must be achieved by relying on the entire tower structure. Multi-level stacking is essentially just a continuous increase in tower height, with deep process binding between levels, making true modular stacking impossible. Adjusting production capacity requires redesigning the overall tower structure and process parameters. From laboratory pilot testing to industrial scale-up, a complete engineering redesign is necessary, resulting in extremely poor flexibility in capacity expansion and hindering standardized and universal production.

[0003] Interference in flow channel design limits mass and heat transfer efficiency: In the integrated process structure, the flow channels of gas phase, liquid phase, and heat medium interfere with each other. During the upward flow of the gas phase, it needs to pass through multiple layers of liquid phase, which can easily lead to problems such as gas phase back mixing, pressure buildup, and liquid accumulation, directly resulting in a decrease in separation purity and limited heat and mass transfer efficiency. At the same time, the internal flow channels of the equipment are an integrally connected structure. Once scaling, blockage, or corrosion occurs, the entire machine must be shut down for disassembly and repair, which is difficult to maintain, has a long downtime, and results in high operation and maintenance costs.

[0004] The structure and function cannot be balanced, and the adaptability to working conditions is poor: Although traditional circular towers have the structural advantages of self-support, uniform stress and strong pressure bearing capacity, they lack modular stacking design and cannot achieve flexible capacity expansion; although traditional polygonal / non-circular modular towers have the characteristics of easy docking and high space utilization, they have problems such as uneven stress, poor pressure bearing capacity and high processing difficulty. They cannot simultaneously meet the dual requirements of structural self-support and modular expansion, and are difficult to adapt to working conditions with different throughput and different installation space requirements.

[0005] The gas phase discharge structure is unreasonable and cannot be adapted to large-scale continuous production: The gas phase discharge of existing modular towers mostly adopts the design of internal short channels or external parallel pipelines. The internal short channels have high flow resistance and are prone to liquid accumulation and pressure buildup. The external pipeline design is complex, making installation and maintenance difficult. Moreover, the gas phase discharge between layers interferes with each other, which seriously affects the separation effect and cannot meet the stable operation requirements of large-scale continuous industrial production.

[0006] In summary, existing distillation or evaporation processes are limited by the structural defects of monolithic towers, and cannot fundamentally solve the core pain points of process coupling, limited capacity expansion, and difficulty in balancing structure and function. The industry urgently needs a new countercurrent distillation or evaporation process that breaks through the limitations of traditional monolithic processes, takes the independent and complete single-layer process as the core, can be modularly stacked, and has flexible and adjustable capacity. Summary of the Invention

[0007] (a) Technical problems to be solved To address the aforementioned shortcomings of existing integrated distillation or evaporation processes, the present invention aims to provide a modular, multi-layer countercurrent distillation or evaporation process with independent single-layer processes. This fundamentally solves the technical problems of traditional processes, such as the lack of complete process capabilities at each single layer, strong coupling between processes, inflexible capacity expansion, low mass and heat transfer efficiency, high maintenance difficulty, and the inability to balance structure and function. It achieves the standardization, modularization, high efficiency, and universality upgrade of distillation or evaporation processes, while maximizing the expansion of the process's operating condition adaptability and reducing production and maintenance costs.

[0008] (II) Technical Solution To achieve the above objectives, the present invention provides the following technical solution: a modular multi-layer countercurrent distillation or evaporation process with independent single-layer technology, comprising steps of liquid phase medium transportation, heat medium transportation, gas-liquid countercurrent contact heat exchange, gas phase product separation and discharge, and liquid phase product collection. This process is implemented using a device composed of at least one standardized tower unit modularly stacked vertically. Each tower unit integrates a liquid phase flow channel, a heat medium flow channel, and a gas phase space. At least one vertical gas phase channel communicating with the gas phase space of the same layer is provided on the side wall. The stacked tower units are connected to each other through an interlayer sealing structure to achieve channel communication. The process specifically includes the following steps: Step 1: Each tower unit independently completes the complete distillation or evaporation process, including liquid medium film formation, gas-liquid countercurrent contact heat exchange, and gas-phase product separation and collection. The process operation of each tower unit is independent and uncoupled. Step 2: Control the liquid medium to flow from top to bottom through the liquid flow channel of each tower unit under the action of gravity, and at the same time control the hot medium to be transported from bottom to top to the hot medium flow channel of each tower unit, so that the liquid medium and the hot medium form independent counter-current contact heat exchange inside each tower unit. Step 3: The gaseous products generated by heat exchange in each tower unit are collected in the gaseous space of that layer and discharged independently through the vertical gaseous channel on the side wall of that layer. The gaseous discharge process of each layer does not interfere with each other. Step 4: Based on the target material processing capacity requirements, increase or decrease the number of vertical stacked layers of the tower unit, and connect them only through the interlayer flow channels to achieve linear scaling up or down of the distillation or evaporation capacity.

[0009] Furthermore, the tower unit adopts any rigid structure, either circular or polygonal; when using a circular tower unit, the multiple layers can achieve overall self-support by their own structure, making it suitable for industrial conditions with high pressure and large processing capacity; when using a square, rectangular, or polygonal tower unit, it is suitable for modular, precise docking and multi-station conditions with limited factory space.

[0010] Furthermore, the tower body unit is made of any one of the rigid metal materials selected from stainless steel, carbon steel, and titanium alloy; for distillation or evaporation of highly corrosive materials, a corrosion-resistant coating or lining is added to the inner wall of the flow channel of the tower body unit.

[0011] Furthermore, in step 3, the number of vertical gas phase channels is one or more, which are uniformly or non-uniformly arranged on the side wall of the tower unit, and the gas phase products discharged from each level of the tower unit are collected and processed separately through independent pipelines.

[0012] Furthermore, in step 2, the heat medium is a gaseous, liquid, or vapor-liquid mixture, and the countercurrent contact heat exchange process between the liquid medium and the heat medium is completed entirely within a single tower unit without interlayer process interference.

[0013] Furthermore, it also includes independent operation and maintenance steps at each level: any single-level tower unit can be inspected, cleaned, or replaced independently without stopping the normal operation of other tower units.

[0014] Furthermore, it also includes a single-level process parameter independent control step: the liquid feed flow rate, heat medium transport flow rate and heat medium temperature of any tower unit can be independently adjusted to precisely control the heat exchange efficiency and separation effect of the corresponding level.

[0015] Furthermore, the process is applicable to chemical separation and evaporation heat exchange processes such as ammonia water separation, wastewater evaporation, organic solvent recovery, traditional Chinese medicine concentration, high-salt wastewater concentration, and multi-component distillation.

[0016] (III) Beneficial Effects Compared with existing technologies, this invention provides a modular multilayer countercurrent distillation or evaporation process with independent single-layer processes, which has the following advantages: This single-layer process is an independent modular multi-layer countercurrent distillation or evaporation process. The process of this invention can achieve linear and precise adjustment of production capacity simply by adding or removing the number of stacked tower units. There is no need to redesign the overall process and equipment structure. It is suitable for all stages of needs from laboratory pilot-scale and pilot-scale to large-scale industrial production, which greatly shortens the project construction cycle and engineering design costs. It solves the industry problem that traditional process capacity adjustment requires overall redesign.

[0017] In the process of this invention, gas-liquid countercurrent heat exchange is completed independently within a single layer without interlayer process interference. The thin liquid film formed by the liquid phase medium significantly increases the heat and mass transfer contact area. At the same time, gas phase products are discharged independently through the vertical gas phase channel on the side wall, with low flow resistance, which fundamentally avoids problems such as gas phase back mixing, pressure buildup, and liquid accumulation.

[0018] The process of this invention can be adapted to tower units of any structure, such as circular or polygonal. The circular structure is suitable for continuous production conditions with high pressure and large throughput, while the polygonal structure is suitable for flexible small-batch production conditions with limited space and multiple workstations. At the same time, it can be adapted to various materials and heat medium types, and can be widely used in various chemical separation processes such as ammonia water separation, industrial wastewater evaporation, organic solvent recovery, traditional Chinese medicine concentration, high-salt wastewater concentration, and multi-component distillation. It has extremely strong versatility and adaptability.

[0019] In the process of this invention, each level of tower unit operates independently, and any level can be inspected, cleaned, or replaced individually without overall shutdown, reducing downtime by more than 90% compared to traditional processes. At the same time, the tower unit is a standardized modular design, which is easy to process, transport, and install, reducing equipment processing costs and project construction costs compared to traditional processes, and significantly reducing the total life cycle operation and maintenance costs.

[0020] The process of this invention adopts a single-layer independent heat exchange mode, which reduces the long-distance heat conduction loss of traditional integral processes, eliminates the additional heat loss of complex external pipelines, and has higher energy utilization efficiency, meeting the development needs of industrial energy conservation and consumption reduction.

[0021] In the process of this invention, the gas phase is discharged independently in layers without interlayer interference, which completely avoids the operational safety hazards caused by pressure buildup and liquid accumulation; the interlayer connection sealing structure simultaneously achieves flow channel sealing and structural fixation, preventing fluid leakage; the circular tower unit has excellent self-supporting performance, the overall structure is stable, the continuous operation cycle and safety of the equipment are greatly improved, and it is fully adapted to the needs of large-scale continuous industrial production. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the core overall process flow of the present invention; Figure 2 This is a schematic diagram of the independent closed-loop process flow of a single tower unit according to the present invention; Figure 3This is a schematic diagram of the multi-layer modular superimposed linear capacity adjustment process of the present invention; Figure 4 This is a schematic diagram of the specific implementation process of the ammonia distillation and separation of the present invention; Figure 5 This is a schematic diagram of the process flow for the evaporation and concentration of high-salt wastewater according to the present invention. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] Please see Figures 1 to 5 The modular, multi-layered, countercurrent distillation or evaporation process disclosed in this invention, with its core principle of achieving a complete process loop at a single level through standardized single-tower units, breaks the limitations of strong coupling between levels in traditional monolithic towers. Simultaneously, it achieves linear capacity adjustment through multi-layered modular stacking. The implementation process of this technology is described in detail below through examples under different operating conditions.

[0025] Example 1: This example provides an ammonia distillation and separation process implemented using a circular tower unit stacking device, as detailed below: The implementation device consists of three layers of standardized circular tower units stacked vertically. The tower units are made of 304 stainless steel, with a diameter of 1200mm and a height of 800mm per layer. Each tower unit integrates a falling film liquid phase channel, a shell-side hot medium channel, and a sealed gas phase space. Two 100mm diameter circular vertical gas phase channels are evenly arranged on the side wall of each tower unit, and the vertical gas phase channels are only connected to the gas phase space of the same layer. The liquid phase channel and the hot medium channel are connected and sealed between layers through a flange-type connection sealing structure to achieve leak-free connection between the liquid phase channel and the hot medium channel. It is equipped with corresponding liquid phase transfer pumps, hot medium circulation pumps, and other medium delivery systems.

[0026] Process steps and operating parameters: Single-layer independent closed-loop operation: Each tower unit independently completes the complete distillation process of dilute ammonia water liquid phase film formation, gas-liquid countercurrent contact heat exchange, ammonia separation and collection. The operation of each level of the process is independent and uncoupled. Ammonia water distillation and separation can be completed independently by connecting a single level to a separate pipeline.

[0027] Gas-liquid two-phase countercurrent directional conveying: A dilute ammonia solution with a controlled mass concentration of 18% is conveyed at a flow rate of 5m... 3A flow rate of / h enters from the liquid phase inlet of the top tower unit and flows from top to bottom through the falling film liquid phase channels of each tower unit under gravity, forming a uniform thin liquid film on the inner wall of the channel. At the same time, saturated water vapor at 0.6MPa is controlled as the heat medium and enters the heat medium channel of the bottom tower unit from the bottom of the device. It is then transported from bottom to top to each tower unit, forming an independent countercurrent contact heat exchange with dilute ammonia water inside each tower unit.

[0028] The gaseous products are discharged independently in layers: the ammonia gas generated by heat exchange and evaporation in each layer of the tower unit is collected in the gas phase space of this layer and discharged independently through the vertical gas phase channel on the side wall of this layer. The ammonia gas discharged from each layer is collected into the ammonia absorption system through independent pipelines. The gas phase discharge of each layer does not interfere with each other and there is no gas phase back mixing or pressure buildup.

[0029] Flexible capacity adjustment: In this embodiment, the rated processing capacity of the three-layer tower unit is 5m³. 3 / h, when production demand increases to 10m 3 When the capacity is / h, simply increase the number of tower unit stacking layers to 6 layers to complete the interlayer flow channel docking and sealing. There is no need to adjust the core process parameters, and the production capacity can be linearly scaled up.

[0030] Process control and operation and maintenance: In this embodiment, the feed rate of dilute ammonia and the steam delivery flow rate of each tower unit can be adjusted independently to precisely control the distillation and separation effect of each layer; when scale forms in one of the tower units and cleaning is required, the feed, gas inlet and gas phase discharge valves of that layer can be closed to carry out online cleaning operations independently without stopping the normal production operation of the other two layers.

[0031] Implementation Results: This embodiment demonstrates stable continuous operation, achieving an ammonia separation purity of 99.8%. The distillation efficiency is 32% higher than that of a traditional integrated ammonia distillation tower of the same specifications, heat loss is reduced by 28%, single-level maintenance does not require overall shutdown, and operation and maintenance costs are reduced by 45%. It is fully adapted to the needs of large-scale continuous industrial production.

[0032] Example 2: This example provides a high-salt wastewater evaporation and concentration process implemented using a square tower unit stacking device, as detailed below: Implementation device: It adopts two layers of standardized square tower units stacked vertically. The tower unit is made of 2205 duplex stainless steel, and the inner wall of the flow channel is lined with a corrosion-resistant polytetrafluoroethylene lining. The size of a single tower unit is 800mm×800mm×600mm. Each tower unit integrates a plate-type liquid phase flow channel, a tube-side hot medium flow channel, and a gas phase space. Each tower unit has an 80mm×150mm rectangular vertical gas phase channel on its side wall, which is only connected to the gas phase space of the same layer. The flow channels are connected between layers through a gasket-type connection sealing structure, which is suitable for multi-station working conditions with limited plant space and is equipped with a corresponding medium delivery system.

[0033] Process steps and operating parameters: Single-layer independent closed-loop operation of the entire process: Each tower unit independently completes the complete evaporation process of high-salt wastewater liquid phase film formation, gas-liquid countercurrent contact heat exchange, and secondary steam evaporation and separation. The operation of each level of the process is independent and uncoupled.

[0034] Gas-liquid two-phase countercurrent directional transport: High-salt wastewater with an initial TDS of 80000 mg / L is transported at a rate of 2m... 3 A flow rate of / h enters from the liquid phase inlet of the top tower unit and flows from top to bottom through the plate liquid phase channels of each tower unit under the action of gravity, forming a uniform thin liquid film; at the same time, heat transfer oil at 180℃ is used as the heat medium and is transported from bottom to top to the heat medium channels of each tower unit, forming an independent countercurrent contact heat exchange with the high-salt wastewater inside each tower unit.

[0035] Independent discharge of gaseous products in layers: The secondary steam generated by heat exchange and evaporation in each layer of the tower unit is collected in the gaseous space of this layer and discharged independently through the vertical gaseous channel on the side wall of this layer. It enters the condensation system through independent pipelines. The gaseous discharge of each layer does not interfere with each other, and there is no liquid accumulation or pressure buildup.

[0036] Flexible capacity adjustment: In this embodiment, the rated processing capacity of the two-layer tower unit is 2m³. 3 / h, when production demand decreases to 1m 3 When the capacity is reduced to / h, only one tower unit needs to be removed and the pipeline connection adjusted to achieve linear capacity reduction without redesigning the process.

[0037] Process control and operation and maintenance: In this embodiment, the wastewater feed flow rate, heat transfer oil flow rate and temperature of each tower unit can be adjusted independently to accurately control the evaporation and concentration ratio of wastewater; In view of the characteristic of high-salt wastewater being prone to scaling, the scaling tower unit can be disassembled and cleaned offline without overall shutdown and without affecting the normal operation of other levels.

[0038] Implementation Results: This embodiment demonstrates stable continuous operation, achieving an 8-fold concentration ratio for high-salt wastewater, a 27% increase in evaporation efficiency compared to traditional integrated evaporators of the same specifications, a 24% reduction in heat loss, and online maintenance without requiring a complete shutdown, resulting in a 40% reduction in maintenance costs. It is perfectly suited for multi-station, small-batch production environments with limited space.

[0039] Comparative Example: This comparative example uses a conventional monolithic distillation column for ammonia distillation separation, serving as a control for Example 1, as follows: It adopts a traditional integral circular distillation column with a diameter of 1200 mm and a height of 2400 mm. It has three layers of floating valve trays and processes 18% dilute ammonia water as feedstock. The rated throughput is 5 m³ / s. 3 / h, the heat medium is 0.6MPa saturated steam, and the raw material parameters, processing capacity and heat medium parameters are completely consistent with those in Example 1.

[0040] Comparative Results: The ammonia separation purity in this comparative example is only 98.2%, the distillation efficiency is 32% lower than that of Example 1, and the heat loss is 39% higher than that of Example 1. If any tray needs maintenance or cleaning, the entire system must be shut down, with a single maintenance downtime of no less than 8 hours, resulting in maintenance costs 85% higher than that of Example 1. When production demand increases to 10m³... 3 When the capacity is reduced to a certain level, the tower structure must be redesigned, and the tower diameter and height must be changed. The engineering design and equipment modification cycle exceeds 3 months, making it impossible to achieve rapid capacity adjustment.

[0041] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A modular multi-layer countercurrent distillation or evaporation process with independent single-layer technology, comprising the steps of liquid-phase medium transport, heat-phase medium transport, gas-liquid countercurrent contact heat exchange, gas-phase product separation and discharge, and liquid-phase product collection, characterized in that, The process is implemented using a device composed of at least one standardized tower unit modularly stacked vertically. Each tower unit integrates a liquid phase flow channel, a heat medium flow channel, and a gas phase space. At least one vertical gas phase channel communicating with the gas phase space of the same layer is provided on its sidewall. The stacked tower units are connected to each other via an interlayer sealing structure to ensure flow channel connectivity. The process specifically includes the following steps: Step 1: Each tower unit independently completes the complete distillation or evaporation process, including liquid medium film formation, gas-liquid countercurrent contact heat exchange, and gas-phase product separation and collection. The process operation of each tower unit is independent and uncoupled. Step 2: Control the liquid medium to flow from top to bottom through the liquid flow channel of each tower unit under the action of gravity, and at the same time control the hot medium to be transported from bottom to top to the hot medium flow channel of each tower unit, so that the liquid medium and the hot medium form independent counter-current contact heat exchange inside each tower unit. Step 3: The gaseous products generated by heat exchange in each tower unit are collected in the gaseous space of that layer and discharged independently through the vertical gaseous channel on the side wall of that layer. The gaseous discharge process of each layer does not interfere with each other. Step 4: Based on the target material processing capacity requirements, increase or decrease the number of vertical stacked layers of the tower unit, and connect them only through the interlayer flow channels to achieve linear scaling up or down of the distillation or evaporation capacity.

2. The modular multi-layer countercurrent distillation or evaporation process with independent single-layer process as described in claim 1, characterized in that, The tower unit adopts any rigid structure, either circular or polygonal. When using a circular tower unit, multiple layers can be stacked together to achieve overall self-support, making it suitable for industrial conditions with high pressure and large throughput. When using square, rectangular, or polygonal tower units, it is suitable for modular, precise docking and multi-station conditions with limited factory space.

3. A modular multilayer countercurrent distillation or evaporation process with independent single-layer technology according to claim 1 or 2, characterized in that, The tower body unit is made of any one of the rigid metal materials, such as stainless steel, carbon steel, or titanium alloy; for distillation or evaporation of highly corrosive materials, a corrosion-resistant coating or lining is added to the inner wall of the flow channel of the tower body unit.

4. The modular multi-layer countercurrent distillation or evaporation process with independent single-layer process as described in claim 1, characterized in that, In step 3, there is one or more vertical gas phase channels, which are uniformly or non-uniformly arranged on the side wall of the tower unit. The gas phase products discharged from each level of the tower unit are collected and processed separately through independent pipelines.

5. The modular multilayer countercurrent distillation or evaporation process with independent single-layer process as described in claim 1, characterized in that, In step 2, the heat medium is a gaseous, liquid, or vapor-liquid mixture. The countercurrent heat exchange process between the liquid medium and the heat medium is completed entirely within a single tower unit without interlayer process interference.

6. The modular multi-layer countercurrent distillation or evaporation process with independent single-layer process as described in claim 1, characterized in that, It also includes independent operation and maintenance steps at each level: any single-level tower unit can be inspected, cleaned, or replaced independently without stopping the normal operation of other tower units.

7. The modular multi-layer countercurrent distillation or evaporation process with independent single-layer process as described in claim 1, characterized in that, It also includes independent control steps for single-level process parameters: the liquid feed rate, heat medium transport flow rate and heat medium temperature of any tower unit can be independently adjusted to precisely control the heat exchange efficiency and separation effect of the corresponding level.

8. The modular multilayer countercurrent distillation or evaporation process with independent single-layer process as described in claim 1, characterized in that, The process described is applicable to chemical separation and evaporation heat exchange processes such as ammonia water separation, wastewater evaporation, organic solvent recovery, traditional Chinese medicine concentration, high-salt wastewater concentration, and multi-component distillation.

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