Customized Equipment Design

In the industrial manufacturing sector, product updates occur rapidly, and processes are becoming increasingly complex. Standard equipment often fails to meet these evolving demands. Customized equipment has become a key strategy for companies to enhance competitiveness and address process challenges. How can customized design truly adapt to the unique requirements of supercritical CO₂ and solvent extraction?

The first step in customized design is to accurately understand the customer's needs. It is essential to go beyond superficial parameters and delve into underlying issues.

A botanical extraction company using supercritical CO₂ extraction equipment required eight hours to extract a specific active ingredient, achieving only a 65% extraction yield with batch-to-batch purity variations exceeding 5%. An on-site investigation by the design team revealed that the core issues were an uneven flow field within the extraction vessel, slow pressure and temperature response, and an inability to quickly adjust parameters for raw materials with varying particle sizes and moisture contents. The customer needed not only "faster extraction" but also "adaptability to diverse raw materials, batch consistency, and high extraction yield."

Specific Approaches:

( 1 )Process Breakdown: Divide the entire extraction process into steps including raw material pretreatment, CO₂ pressurization, extraction reaction, separation and collection, and solvent recovery. Identify key indicators for each step, such as pressure accuracy (±0.1 MPa), temperature control (±1°C), extraction vessel agitation speed (adjustable from 5–30 rpm), and solvent recovery rate (≥98%).
( 2 ) Problem Translation: Convert concerns such as "low extraction rate," "inconsistent batches," and "slow material changeover and commissioning" into specific quantitative requirements. Examples include a raw material particle size range of 50–200 mesh, parameter adjustment time after material change of <30 minutes, active ingredient extraction rate ≥92%, and batch purity variation of ≤1.5%.
( 3 )Scenario Simulation: Use process simulation software to replicate real production conditions, simulating changes in mass transfer efficiency and energy consumption under different raw material characteristics (moisture content 8%–15%) and pressure ranges (10–35 MPa). This helps identify potential equipment issues early, such as local overheating or excessive solvent retention.

 Customized extraction equipment integrates mechanical structure, electrical control, and software systems, requiring multidisciplinary collaboration to meet specific process needs.

1.Mechanical Design

It must satisfy high-pressure sealing requirements while improving mass transfer efficiency and material compatibility. In a customized solvent extraction equipment project for a traditional Chinese medicine company, the design team upgraded the traditional static extraction vessel to a dynamic structure with spiral agitation and pulsed liquid distribution. Combined with a 316L stainless steel porous distribution plate, this increased the solvent–raw material contact area by 40%, reducing extraction time from 6 hours to 3.5 hours. Quick-opening flanges and interchangeable screens were also incorporated to accommodate the loading, unloading, and filtration needs of raw materials with varying particle sizes.

2. Electrical Control

​It must enable precise dynamic adjustment of process parameters. In the aforementioned project, the team implemented a distributed PLC control system to collect signals from over 20 sensors, including extraction vessel pressure sensors, jacket temperature transmitters, and solvent flow sensors. PID closed-loop control achieved millisecond-level pressure and temperature response, addressing the uneven extraction caused by slow parameter adjustments in conventional equipment. Explosion-proof electrical components were also used to accommodate extraction environments involving flammable solvents such as ethanol.

3. Software Development

It requires dedicated algorithms to enhance process accuracy and stability. In a supercritical CO₂ extraction equipment project, the software team developed an automatic parameter-matching algorithm based on raw material characteristics. By collecting historical extraction data (raw material particle size, moisture content, and target component content) and building a database, the system automatically recommends optimal pressure, temperature, and extraction time settings when raw materials are changed. A real-time monitoring module was also implemented to provide early warnings for abnormalities in parameters such as CO₂ flow rate and separation vessel liquid level during extraction, reducing fluctuations in component extraction yield from ±4% to ±0.8%.

1. Material and Component Selection

( 1 ) Consider corrosion resistance, high-pressure sealing, and process compatibility:
① Extraction vessels and piping exposed to acidic or alkaline solvents should be constructed from 316L stainless steel or Hastelloy to prevent solvent corrosion, equipment leakage, and material contamination.
② High-pressure valves and seals in supercritical systems should use polytetrafluoroethylene and metal-wound composite gaskets, capable of withstanding pressures exceeding 35 MPa and having a service life of over 1,000 cycles.
③ The condenser in the solvent recovery system should use a high-efficiency titanium tube heat exchanger, suitable for rapid condensation and recovery of low-boiling-point solvents (e.g., ethanol, ethyl acetate), increasing recovery rates to over 99%.
( 2 )When selecting materials, balance performance and cost. For common botanical extraction processes, titanium heat exchangers are unnecessary; 316L stainless steel is sufficient, avoiding over-engineering.

2. Modular Design

Divide the equipment into independent units, such as raw material pretreatment, extraction reaction, separation and recovery, and solvent circulation modules, connected via standardized flanges and piping interfaces. A health supplement company's multifunctional extraction production line, using this approach, can quickly switch between supercritical CO₂ extraction and ethanol solvent extraction by replacing agitation components in the extraction vessel and the filter membrane in the separation module. This reduces equipment modification costs by 65% and enables the system to adapt to the extraction requirements of different active ingredients.

3. Safety and Reliability

In addition to hardware protections such as high-pressure safety valves, explosion-proof pressure relief devices, and safety light curtains, software safety logic must be enhanced:
( 1 )If the extraction vessel pressure exceeds the set value by 10%, the system automatically activates the pressure relief valve and cuts off heating power.
( 2 ) If the solvent storage tank liquid level falls below the warning value, an audible and visual alarm is triggered, and the feed pump is paused.
( 3 )If the sealing cover is not locked during operation, the equipment immediately shuts down and records the fault location and cause for subsequent troubleshooting.

1. Design Phase

( 1 ) Use finite element analysis software to simulate the strength of the extraction vessel shell, ensuring no deformation or leakage under the ultimate pressure of 40 MPa, thereby avoiding safety risks associated with high-pressure operation.
( 2 )Use process simulation software to simulate flow field distribution within the vessel at different flow rates, optimizing impeller speed and liquid distribution port placement to address localized low mass transfer efficiency.
( 3 )Perform control logic simulation tests, simulating abnormal conditions such as voltage fluctuations and sensor failures, to verify the system's ability to handle emergency shutdowns and parameter resets.

2. Prototype Phase

( 1 )Conduct 168 hours (7 days) of continuous operation testing, performing extraction tests on three typical raw materials (e.g., honeysuckle, salvia miltiorrhiza) to measure equipment operational stability (failure rate ≤0.5%) and energy consumption.
( 2 )Perform trial production of 10 batches of raw materials, testing key indicators such as extraction yield (≥92%), purity variation (≤1.5%), and solvent residue (≤5 ppm) to validate process suitability.
( 3 ) Conduct extreme tests: under conditions of ±15% voltage fluctuation and 20% excess raw material moisture content, examine the equipment's parameter adjustment capabilities and product quality stability.
( 4 ) A supercritical CO₂ extraction equipment unit passed acceptance testing, achieving a target active ingredient extraction yield of 94.2% and a solvent recovery rate of 99.3%, with batch-to-batch variation of only 0.9%, far exceeding customer expectations.

The future of customized design for supercritical CO₂ and solvent extraction equipment will emphasize three key features:

1.Data-Driven Approach

Install in-line sensors for pressure, temperature, flow, and composition at key equipment locations to collect real-time process data and optimize extraction parameters using machine learning algorithms. For example, one system automatically adjusts CO₂ flow rate and extraction time based on real-time raw material moisture content, improving extraction efficiency by 12%.

2.Digital Twin Technology

 Develop a virtual model of the equipment, mapping real-world operating conditions, material properties, and process parameters in real time. Simulate different process strategies to optimize operations in advance and predict replacement times for consumable parts such as seals and filters, reducing maintenance downtime by 40%.

3.Hardware–Software Decoupling

Use a universal hardware platform, including pressure vessels and piping, paired with a customizable software control system and modular functional units. Customers can later upgrade processes by updating software algorithms or replacing extraction modules, eliminating the need for new equipment purchases. This reduces customization costs by over 30%.
For example, one equipment manufacturer's intelligent supercritical extraction system includes not only customized hardware but also a built-in database of extraction parameters for over 200 botanical ingredients. Customers can use this database for rapid debugging, reducing process development time for new raw materials from 15 days to 3 days.

The key to designing customized extraction equipment lies in balancing technical feasibility, process adaptability, and cost control. Success depends not only on innovations in mechanical structure or control technology but also on a deep understanding of the mass transfer principles of supercritical CO₂ and solvent extraction, multidisciplinary collaborative design, and a comprehensive lifecycle service approach. As industries such as pharmaceuticals and health supplements demand increasingly precise and efficient extraction of natural ingredients, customized equipment that can quickly adapt to process changes and continuously optimize extraction performance will become a core component of a company's competitive advantage.