A cold-pressing original liquid integrated liquor ethanol and flavor ester synchronous recovery process

Abstract

The application discloses a high-pressure cold-pressing raw liquor coupled negative-pressure side-line extraction integrated liquor ethanol and flavor ester synchronous recovery process and belongs to the technical field of liquor brewing and fine separation. The application takes fermented grains as raw materials, and crude liquor raw liquor without high-temperature damage is prepared through a high-pressure normal-temperature cold-pressing mode. The raw liquor is directly connected to a negative-pressure rectification system in a sealed mode, and ethanol purification and low-boiling-point light ester automatic recovery are realized through low-temperature negative-pressure rectification. Meanwhile, a side-line countercurrent extraction structure is arranged in the rectification tower, and in-situ extraction and recovery of high-boiling-point heavy esters in the liquor body are realized. The single set of equipment synchronously completes the graded recovery of ethanol, light esters and heavy esters, and the whole process is connected to a PLC central control system to realize 24-hour continuous production in an automatic mode.

Description

Technical Field

[0001] This invention relates to the field of refined separation and flavor substance recovery technology in Baijiu brewing, specifically to an integrated production process based on high-pressure cold pressing of fermented mash, combined with negative pressure low-temperature distillation and countercurrent extraction in the inner side stream of the tower, to achieve simultaneous, efficient and automated recovery of Baijiu ethanol and high and low boiling point flavor esters. Background Technology

[0002] Traditional solid-state liquor brewing generally employs a still-distillation process at atmospheric pressure and high temperature, typically maintaining a distillation temperature between 85℃ and 100℃. This process has inherent technical drawbacks: the high-temperature environment causes significant hydrolysis and volatilization of heat-sensitive substances in the liquor, such as ethyl hexanoate, ethyl lactate, and ethyl acetate, resulting in insufficient flavor complexity and a low overall recovery rate of flavor compounds. Furthermore, the traditional processes of loading the still, distilling, unloading, and collecting the liquor are highly dependent on manual labor, leading to high labor costs and hindering large-scale, automated, and continuous production.

[0003] Existing low-temperature negative pressure distillation technology is mostly used for secondary de-alcoholization and purification of finished liquor. Its pre-extraction process still uses traditional stilling or ordinary spiral low-pressure pressing. The process is fragmented, the materials need to be manually transferred and repeatedly filtered, the degree of automation is low, and the problem of liquor production and flavor preservation is not solved from the source.

[0004] Existing flavor ester recovery processes mostly involve "external secondary extraction of the residue at the bottom of the vessel after distillation," which is a separate post-processing process. This process requires large equipment investment, has a long process flow, and low-boiling-point esters will evaporate and be lost prematurely with ethanol vapor. High and low-boiling-point esters cannot be recovered simultaneously, resulting in low resource utilization and high production costs.

[0005] According to research, there is currently no integrated, continuous, and automated process in the domestic liquor brewing industry that uses high-pressure, ambient-temperature cold-pressed raw liquid from fermented mash as the sole feed source, directly coupled with in-situ countercurrent extraction on the inner side of a negative-pressure distillation tower, and simultaneously separates ethanol and flavor esters of all components. The industry urgently needs a new brewing and separation process that locks in aroma at the source, produces at low temperatures, recovers all components, and is fully automated. Summary of the Invention

[0006] Purpose of the invention:

[0007] This invention aims to overcome the shortcomings of existing traditional high-temperature distillation, such as high flavor loss, high dependence on manual labor, fragmented processes, low ester recovery rate, and the inability to integrate existing negative pressure and extraction processes. It provides a high-pressure cold-pressed raw liquid coupled with negative pressure side-line extraction integrated process for the simultaneous recovery of ethanol and flavor esters in baijiu, realizing automated production of raw liquor, low-temperature purification of ethanol, and graded and simultaneous recovery of high and low boiling point flavor esters. This significantly reduces labor costs and maximizes the retention and recovery of high-value flavor substances in baijiu.

[0008] Technical solution:

[0009] To achieve the above objectives, this invention provides an integrated process for the simultaneous recovery of ethanol and flavor esters from baijiu (Chinese liquor) through high-pressure cold-pressed liquor coupled with negative-pressure side-stream extraction, comprising the following steps:

[0010] 1. Preparation of fermented mash liquid by high-pressure, room-temperature cold pressing

[0011] The fermented grain mash is directly fed into a high-pressure cold-pressing device. Static high-pressure cold pressing is performed at an ambient temperature of ≤35℃ and a pressing pressure of 40MPa~60MPa, achieving solid-liquid separation of solid grain residue and liquid crude liquor in one step. The device is equipped with a self-cleaning precision filter that automatically intercepts suspended solids and grain residue impurities, eliminating the need for manual filtration and cleaning. The separated crude liquor is continuously transported to the negative pressure distillation tower buffer tank through a closed pipeline, while the solid waste is automatically discharged and transported off-site. The entire process is automated and closed, with no open material transfer.

[0012] 2. Negative pressure low-temperature distillation separation and recovery of ethanol and low-boiling-point light esters

[0013] The crude liquor is continuously fed into a packed negative pressure distillation column. The control system stably maintains the vacuum level inside the column at -0.06MPa to -0.075MPa, and the liquid phase in the column bottom is kept at a constant temperature of 55℃ to 65℃. Under low temperature and negative pressure, ethanol preferentially vaporizes to form mixed vapor, which is then discharged from the top of the column and condensed at a constant temperature in a condenser. After condensation, part of the material is high-purity ethanol base, which is automatically collected and stored. The other part contains low-boiling-point flavor esters such as ethyl acetate, which are separated into liquid and ester phases by an automatic oil-water separator. The upper ester phase is automatically overflowed and collected, thus completing the simultaneous recovery of low-boiling-point flavor esters.

[0014] 3. Countercurrent extraction and recovery of high-boiling-point heavy esters via the inner side stream of the distillation column.

[0015] A side-stream extraction structure is set up in the liquid phase enrichment zone in the middle of the negative pressure distillation column. Food-grade extraction solvent is introduced into the column in a countercurrent manner, and the extraction solvent comes into full countercurrent contact with the wine flowing from top to bottom in the column. The core heavy esters in the wine, such as high-boiling-point ethyl hexanoate, ethyl lactate, and ethyl butyrate, are highly soluble in the extraction solvent and are directionally enriched into the oil phase system. The aqueous phase and ethanol phase are insoluble in the oil phase, achieving effective separation. The oil-rich phase, loaded with all the heavy ester flavor substances, is continuously collected through the side-stream pipeline and sent to a vacuum desolventizing tank to remove trace amounts of entrained ethanol at low temperature and negative pressure, finally obtaining a high-concentration compound flavor ester concentrate. The extraction solvent after desolventizing is recycled back to the side-stream system for reuse, realizing closed-loop solvent recycling.

[0016] 4. Continuous automated operation of the entire PLC chain

[0017] The entire set of process equipment is connected to the PLC central control system. The high-pressure cold pressing pressure, distillation column vacuum degree, column bottom temperature, material feed flow rate, solvent circulation flow rate, and tank liquid level are all collected in real time by sensors and automatically adjusted by frequency conversion. The feeding, distillation, extraction, discharge, and residual liquid discharge are all automated and linked. The wastewater residue after the removal of ethanol and esters at the bottom of the column is automatically discharged, realizing 24-hour continuous unattended production.

[0018] Further optimized process parameters are as follows: high-pressure cold pressing pressure of 50MPa, operating ambient temperature ≤35℃; vacuum degree in the distillation column -0.07MPa, constant temperature in the column bottom of 60℃; food-grade propylene glycol is used as the extraction solvent, and the volume ratio of crude liquor to extraction solvent is 8:1.

[0019] Beneficial effects:

[0020] Compared with the prior art, the present invention has the following significant advantages:

[0021] 5. Locks in aroma at the source, with an extremely high flavor recovery rate.

[0022] This invention employs room-temperature, high-pressure cold pressing to extract the liquor, completely eliminating the traditional high-temperature cooking process and preventing the high-temperature hydrolysis and destruction of flavor esters from the source. The entire downstream process operates at a low temperature and negative pressure below 65°C, combined with in-situ extraction via side streams within the tower, achieving simultaneous recovery of all components, including low-boiling-point light esters and high-boiling-point heavy esters. The total flavor ester recovery rate can reach over 94%, and the ester hydrolysis loss rate is less than 3%, greatly improving the quality and flavor added value of the liquor.

[0023] 6. Dramatically reduces costs and achieves a high degree of automation.

[0024] This invention eliminates all traditional positions such as manual loading of the still, manual slag filtering, manual transfer, and manual wine receiving. The entire process is automated through closed pipelines and operated by PLC without human intervention, reducing labor costs by more than 70% and significantly improving production efficiency.

[0025] 7. Process integration results in lower equipment energy consumption.

[0026] This system integrates multiple processes, including raw material preparation, ethanol purification, light ester recovery, and heavy ester extraction, into a single continuous equipment system. It abandons the traditional separate equipment operation mode, resulting in a small footprint, short process, low energy consumption, and significantly reduced production costs for large-scale production.

[0027] 8. High-value utilization of all components

[0028] A single process can simultaneously produce three high-value products: high-purity ethanol base, highly complex flavor ester concentrate, and high-quality raw liquor system, achieving 100% high-value utilization of fermented mash resources and breaking through the traditional single model of profiting solely from the liquor itself.

[0029] 9. Strong technological innovation

[0030] It pioneered an integrated process that directly connects high-pressure cold-pressed mash to a negative-pressure distillation tower, and also pioneered a coupled structure for in-situ countercurrent extraction of heavy esters from the inner side of the distillation tower. This is distinct from all separate and post-extraction processes in the industry, demonstrating outstanding technological originality. Attached Figure Description

[0031] Figure 1 A system diagram of cold-pressed and ethanol-flavored esters;

[0032] 101 High-pressure cold pressing unit;

[0033] 102 Self-cleaning precision filter;

[0034] 103 Automatic slag discharge valve;

[0035] 104. Closed-loop pump for raw liquid transfer;

[0036] 105 Raw material buffer tank;

[0037] 106 Negative Pressure Distillation Main Column;

[0038] 107 Water ring vacuum pump set;

[0039] 108. Tower bottom constant temperature heat exchanger assembly;

[0040] 109. Steam outlet at the top of the tower;

[0041] 110 Shell and tube condenser;

[0042] 111 Ethanol finished product storage tank;

[0043] 112 Automatic oil-water separator (for collecting light grease);

[0044] 113 Light grease storage tank;

[0045] 114. Side-stream extraction inlet in the middle of the distillation column;

[0046] 115 Extraction solvent circulation tank;

[0047] 116 Side-stream rich oil discharge port;

[0048] 117. Pressure relief and tank unloading;

[0049] Figure 2 This is a simplified structural diagram of a high-pressure cold press.

[0050] 201 High-pressure hydraulic cylinder;

[0051] 202. Interlayer on the outer wall of the cylindrical barrel;

[0052] 203 Pressure-bearing crushing silo;

[0053] 204 Automatic Spiral Slag Discharge Device;

[0054] 205. Dried distiller's grains;

[0055] Figure 3 Detailed internal structure diagram of the side-stream extraction of a pressureless distillation column;

[0056] 301 Upper layer ethyl ester distillation packing material;

[0057] 302 Middle Countercurrent Extraction Packing Material;

[0058] 303 Lower stripping section;

[0059] Figure 4 This is a block diagram of PLC automation control logic.

[0060] 401 Pressing pressure sensor;

[0061] 402 Distillation Vacuum Sensor;

[0062] 403 Tower bottom temperature sensor;

[0063] 404 Inlet / Outlet Flow Sensor;

[0064] 405 Tank Level Sensor;

[0065] 406 Feed pump frequency converter module;

[0066] 407 Vacuum pump frequency adjustment module;

[0067] 408 Temperature-controlled heating / cooling valve;

[0068] 409 Side-stream solvent delivery pump;

[0069] 410 Each discharge electric valve;

[0070] PLC main control unit. Detailed Implementation

[0071] The present invention will be further described in detail below with reference to specific embodiments.

[0072] Example 1

[0073] A process for the simultaneous recovery of ethanol and flavor esters from baijiu (Chinese liquor) using a high-pressure cold-pressed raw liquid coupled with negative pressure side-stream extraction includes the following steps:

[0074] Selected fermented and matured strong-aroma sorghum solid liquor mash is fed into a high-pressure cold-pressing device, and the ambient temperature is controlled at 32℃ and the pressing pressure at 50MPa for room temperature cold pressing. The device's self-cleaning filter automatically filters impurities, and the resulting crude liquor is pumped into the raw material buffer tank of a negative pressure distillation tower through a closed pipeline, while the waste residue is automatically discharged.

[0075] The negative pressure distillation system is started, the vacuum degree inside the column is stabilized at -0.07MPa, and the temperature of the column bottom is kept constant at 60℃; the crude liquor raw liquid continuously enters the distillation column for distillation and separation, the ethanol mixed vapor at the top of the column is condensed by the condenser, and high-purity ethanol of more than 75% vol is collected; the condensed mixture enters the oil-water separator, and the upper layer of ethyl acetate light ester component is automatically collected in layers.

[0076] Food-grade propylene glycol extraction solvent is introduced into the side stream in the middle of the distillation column, and the volume ratio of raw liquid to solvent is controlled at 8:1. The heavy ester components of ethyl hexanoate and ethyl lactate in the liquor are extracted in a countercurrent manner. The oil phase enriched with flavor esters is continuously collected from the side stream. After desolventizing under reduced pressure, a high-concentration compound liquor flavor ester concentrate is obtained, and the solvent is automatically refluxed and recycled.

[0077] The entire system is automatically controlled by a PLC central control unit, ensuring stable production for 24 hours a day, requiring only routine equipment inspections.

[0078] Example 2

[0079] Fermented, aromatic corn mash was selected and processed using the same parameters: high pressure (50 MPa) and room temperature cold pressing for liquid extraction, negative pressure (-0.07 MPa) and constant temperature (60℃) distillation, and propylene glycol side-stream countercurrent extraction.

Claims

1. A process for the simultaneous recovery of ethanol and flavor esters from baijiu (Chinese liquor) through high-pressure cold-pressed liquor coupled with negative-pressure side-stream extraction, characterized in that... The production process includes the following steps: (1) High-pressure cold pressing to produce raw liquor: The fermented grain solid mash is sent into the high-pressure cold pressing equipment and the solid and liquid are separated by cold pressing under the conditions of 40MPa~60MPa and ambient temperature ≤35℃ to obtain crude liquor raw liquor. The equipment is equipped with a self-cleaning filter screen to automatically remove residue. The crude liquor raw liquor is continuously transported to the negative pressure distillation tower through a closed pipeline. (2) Low-temperature distillation of alcohol and recovery of light esters under negative pressure: crude liquor enters a negative pressure distillation column, and the vacuum degree inside the column is controlled at -0.06MPa to -0.075MPa and the temperature of the column bottom is kept constant at 55℃ to 65℃. After the ethanol is vaporized, it is condensed and recovered to obtain the ethanol product. The low-boiling-point flavor light esters carried out with the ethanol vapor are automatically separated into oil and water and collected simultaneously. (3) Countercurrent extraction of heavy esters in the side stream of the column: Food-grade extraction solvent is introduced into the liquid phase enrichment zone in the middle of the negative pressure distillation column and comes into countercurrent contact with the downward wine liquid in the column to extract the high boiling point flavor heavy esters in the wine liquid. The oil-rich phase loaded with flavor esters is collected from the side stream and obtained by desolventizing under reduced pressure to obtain flavor ester concentrate. The extraction solvent is recycled. (4) Automated continuous production: The entire process is controlled by the PLC central control system, and the feeding, distillation, extraction, discharge and residual liquid discharge are all automated and continuous.

2. The integrated high-pressure cold-pressed liquor coupled with negative pressure side-stream extraction process for simultaneous recovery of ethanol and flavor esters in baijiu as described in claim 1, characterized in that: The optimal pressing pressure for the high-pressure cold pressing is 50 MPa, and the operating environment temperature is ≤35℃.

3. The integrated high-pressure cold-pressed liquor coupled with negative pressure side-stream extraction process for simultaneous recovery of ethanol and flavor esters in baijiu as described in claim 1, characterized in that: The extraction solvent is food-grade propylene glycol, and the volume ratio of crude wine concentrate to extraction solvent is 8:

1.

4. The integrated high-pressure cold-pressed liquor coupled with negative pressure side-stream extraction process for simultaneous recovery of ethanol and flavor esters in baijiu as described in claim 1, characterized in that: The optimal parameters for the negative pressure distillation are a vacuum of -0.07 MPa inside the column and a constant temperature of 60°C at the bottom of the column.

5. The integrated high-pressure cold-pressed liquor coupled with negative pressure side-stream extraction process for simultaneous recovery of ethanol and flavor esters in baijiu as described in claim 1, characterized in that: The discharge end of the high-pressure cold pressing equipment and the feed end of the negative pressure distillation tower adopt a closed direct connection structure, with no open material transfer throughout the process, realizing seamless and continuous production of raw liquid production and distillation extraction.

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