I. Project Background

A bio-fermentation company in Heilongjiang Province specializes in the production of organic acids, with its core product, citric acid, having an annual output of 30,000 tons, widely used in the food, pharmaceutical, and daily chemical industries. Traditional processes using precipitation-filtration to separate citric acid suffer from problems such as a lengthy process, high solvent loss (over 500 tons of organic solvent consumed annually), and low product purity (only 92%). Furthermore, the wastewater COD value is as high as 6000 mg/L, resulting in high environmental treatment costs. To overcome these technological bottlenecks, the company introduced a Shandong Liancui LC-250 centrifugal extractor, constructing a closed-loop process of "four-stage countercurrent extraction + back-extraction crystallization."

II. Technical Solution and Equipment Selection

1. Core Equipment Parameters

• Model: LC-250 Centrifugal Extractor

• Processing Capacity: Single unit throughput 100-3000L/h, supports four-stage countercurrent series connection, single line daily processing capacity up to 50m³

• Separation Factor: 400-960G (adjustable speed 1000-1450rpm)

• Material: The drum is made of 316L stainless steel with a fluoropolymer coating, resistant to extreme environments with pH=0-14

• Structure: Non-annular mixing design; the drum is only responsible for separation; the stirring paddle is customized according to the material viscosity.

2. Process Flow Optimization

• Pretreatment Stage: A horizontal screw centrifuge is used for rapid separation of bacterial cells, reducing the subsequent extraction load.

• Extraction Stage: A four-stage countercurrent centrifugal extraction system (flow rate 0.8m³/h) uses trialkylamine (N235) as the extractant, achieving a citric acid extraction rate of 94%, reducing solvent residue from 2.1% to 0.6%. Back-extraction and crystallization: After back-extraction of the supported organic phase with sulfuric acid, high-purity citric acid crystals (purity ≥99.5%) are obtained through evaporation concentration and centrifugal crystallization.

III. Implementation Results and Data Comparison

1. Efficiency Improvement

• Separation Time: Single-stage separation time is reduced from 30 minutes in the traditional process to 8 seconds, and the total processing time of the four-stage system is only 32 seconds.

• Capacity Increase: Daily processing capacity increases from 20 m³ to 50 m³, and annual capacity increases by 15,000 tons.

• Purity Breakthrough: Product purity increases from 92% to 99.5%, meeting EU export standards.

2. Cost Savings

• Solvent Circulation Rate: The closed-loop design achieves an organic solvent recovery rate of 99.5%, saving over 2 million yuan in solvent procurement costs annually.

• Energy Consumption Reduction: Electricity consumption per ton of raw material decreases from 2800 kWh to 1650 kWh, saving over 500,000 yuan in electricity costs annually. Wastewater Treatment Costs: Wastewater COD decreased from 6000 mg/L to 1200 mg/L, reducing wastewater treatment costs by 70%.

3. Environmental Benefits

• Hazardous Waste Reduction: Solvents are recycled more than 200 times, reducing hazardous waste emissions by 60%.

• Carbon Footprint Reduction: Carbon emissions per unit of product decreased by 52%, helping enterprises achieve their "dual carbon" goals.

IV. Technological Breakthroughs and Innovations

1. Enhanced Separation Using Hypergravity Fields
The LC-250 equipment generates a centrifugal force field through high-speed rotation, refining droplet diameters to 50-200 μm, increasing the mass transfer interface area by 3 times compared to traditional equipment. In citric acid extraction, the total extraction rate exceeds 99% after four stages of countercurrent series connection, and the phase separation time is shortened to within 30 seconds, improving efficiency by 3 times compared to traditional extraction towers.

2. Intelligent Anti-Emulsification System
Addressing the emulsifiable nature of bio-fermentation broth, the equipment incorporates an adjustable weir plate and a variable frequency speed control module to dynamically adjust the mixing ratio (1:200 to 200:1), preventing emulsion layer buildup. For example, when processing high-viscosity fermentation broth, optimizing the impeller angle increases mixing efficiency by 40%, reducing emulsion layer thickness from 5mm to 0.2mm.

3. Full Life Cycle Cost Control

• Material Innovation: The 316L stainless steel + fluorine composite structure can withstand strong acid environments, extending equipment lifespan by 3 times compared to traditional carbon steel equipment.

• Modular Design: Supports single-unit multi-level series or parallel connection; capacity increases do not require equipment replacement, reducing investment risk.

• Intelligent Operation and Maintenance: Integrated PLC control system monitors 12 parameters in real time; abnormal alarm response time is <1 second; supports 5G + edge computing remote parameter adjustment.