System for producing polyhydroxyalkanoate

Abstract

The utility model relates to a system for producing polyhydroxyalkanoate. The system is provided with a fermentation unit (3), an enzymolysis unit (5), a plate-and-frame filter press (1) and a flash dryer (2) which are connected in sequence, wherein the plate-and-frame filter press (1) is arranged in front of the flash dryer (2), and the plate-and-frame filter press (1) comprises a filter frame, a filter plate and filter cloth; and the flash dryer (2) comprises a feeder, a stirring and crushing system, a classifier, a drying main pipe, a cyclone separator, a bag-type dust collector and a fan. According to the system disclosed by the utility model, PHA emulsion is subjected to plate-frame pressure filtration to prepare PHA filter cakes containing 70% of dry matters, then the PHA filter cakes are subjected to flash evaporation drying to prepare PHA products, and the system has the advantages of low cost, high efficiency and high recovery rate.

Description

Technical Field

[0001] The utility model belongs to the field of biochemical engineering, and specifically relates to a system for producing polyhydroxyalkanoate at low cost. Background Art

[0002] Polyhydroxyalkanoates (PHA) are intracellular polyesters synthesized by halophilic bacteria. They exist in organisms mainly as storage substances for carbon sources and energy. They have physical and chemical properties similar to those of synthetic plastics and many excellent properties that synthetic plastics do not have, such as biodegradability, biocompatibility, optical activity, piezoelectricity, and gas barrier properties. They are natural polymer biomaterials. PHA is prepared into a PHA emulsion with a dry matter content of 10%-30wt% after fermentation, separation, enzymolysis, and separation processes.

[0003] In order to make PHA more applicable, the purity of PHA must be improved. The traditional process uses a spray tower drying method to further purify 10%-30wt% PHA emulsion, but its cost is high. Therefore, in order to improve economic benefits, the development of a low-cost, high-efficiency, and high-recovery drying method is the only way to industrialization. Utility Model Content

[0004] In order to solve the above technical problems faced by the prior art, the utility model provides a system for producing polyhydroxyalkanoates at low cost. Specifically, the following technical solutions are provided.

[0005] Technical solutions (1)

[0006] A system for producing polyhydroxyalkanoates, characterized in that the system comprises a fermentation unit 3, an enzymatic hydrolysis unit 5, a plate and frame filter press 1 and a flash dryer 2 which are connected in sequence; wherein the plate and frame filter press 1 is arranged before the flash dryer 2, and the plate and frame filter press 1 comprises a filter frame, a filter plate and a filter cloth; the flash dryer 2 comprises a feeder, a stirring and crushing system, a classifier, a drying main pipe, a cyclone separator, a bag filter and a fan.

[0007] Technical solutions (2)

[0008] According to the system of technical solution 1, a polyhydroxyalkanoate layer is pre-coated on the filter cloth.

[0009] Technical solutions (3)

[0010] According to the system of technical solution 1, the feeder is a cyclone feeder.

[0011] Technical solutions (4)

[0012] A system according to Technical Solution 2, wherein the feeder is a cyclone feeder.

[0013] Technical solutions (5)

[0014] According to the system described in Technical Solution 1, the flash dryer 2 also includes an air filter.

[0015] Technical solutions (6)

[0016] According to the system described in Technical Solution 2, the flash dryer 2 also includes an air filter.

[0017] Technical solutions (7)

[0018] According to the system described in Technical Solution 3, the flash dryer 2 also includes an air filter.

[0019] Technical solutions (8)

[0020] According to the system described in Technical Solution 4, the flash dryer 2 also includes an air filter.

[0021] Technical solutions (9)

[0022] According to the system described in any one of technical solutions 1-8, the system is further provided with a fermentation liquid separation unit 4 after the fermentation unit 3 and before the enzymatic hydrolysis unit 5; and an enzymatic hydrolysis liquid separation unit 6 is provided after the enzymatic hydrolysis unit 5 and before the plate and frame filter press 1.

[0023] The system of the utility model prepares PHA emulsion into PHA filter cake with 70% dry matter through plate and frame filter pressing, and then prepares PHA product through flash drying. The system has the advantages of low cost, high efficiency and high recovery rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of an implementation scheme of the utility model.

[0025] Figure 2 It is a schematic diagram of another embodiment of the present invention.

[0026] Among them, 1-plate and frame filter press, 2-flash dryer, 3-fermentation unit, 4-fermentation liquid separation unit, 5-enzyme hydrolysis unit, 6-enzyme hydrolyzate separation unit. DETAILED DESCRIPTION

[0027] The utility model is described in detail below with reference to the accompanying drawings.

[0028] like Figure 1As shown, a system for producing polyhydroxyalkanoates at low cost is characterized in that the system comprises a fermentation unit 3, an enzymatic hydrolysis unit 5, a plate and frame filter press 1 and a flash dryer 2 which are connected in sequence; wherein the plate and frame filter press 1 is arranged before the flash dryer 2, and the plate and frame filter press 1 comprises a filter frame, a filter plate and a filter cloth; the flash dryer 2 comprises a feeder, a stirring and crushing system, a classifier, a drying main pipe, a cyclone separator, a bag filter and a fan.

[0029] The plate and frame filter press comprises a filter plate, a filter frame and a filter cloth. The filter plate and the filter frame are arranged alternately. The filter cloth is covered on both sides of the filter plate. The filter plate and the filter frame are pressed by a pressing device, that is, a filter press chamber is formed between the filter plate and the filter frame. A small hole is opened in the same position in the middle of the upper end of the plate and the frame, which becomes a channel after pressing. Preferably, a polyhydroxyalkanoate layer is pre-coated on the filter cloth.

[0030] Flash dryer 2 is mainly composed of air filter, heater, feeder, hot air distribution chamber, flash dryer, classification chamber, cyclone collector, bag filter, induced draft fan and other main equipment. The paste material from the filter press is initially crushed by stirring in the heater, and then quantitatively fed into the fluidization section of the dryer by the spiral feeder. In the fluidization section, it is further centrifuged and crushed by the stirrer. The fresh air required in the drying process is introduced by the filter, heated to the required temperature during the heating period, and fed into the hot air distributor. It enters the fluidization section at a high wind speed through the slit at the bottom of the dryer, fully contacts with the stirred material, and causes the material to form a fluidized state and begin to boil. Because the material is in a state of centrifugation, stirring, and crushing, the surface of the block (or spherical) material is quickly dried and separated into smaller spherical or irregular spherical particles, which are fed into the classifier under the action of rotating hot air, and the larger and wetter undried particles fall back into the drying chamber. The fine materials sent into the classifier are discharged from the cyclone collector and separated by the bag filter. The air is discharged into the atmosphere through the exhaust fan, and the materials are discharged from the cyclone collector and the bottom of the bag filter.

[0031] like Figure 2 As shown, a system for producing polyhydroxyalkanoates at low cost comprises a fermentation unit 3, a fermentation liquid separation unit 4, an enzymatic hydrolysis unit 5, an enzymatic hydrolyzate separation unit 6, a plate and frame filter press 1 and a flash dryer 2 in sequence.

[0032] Among them, the fermentation unit 3, the fermentation liquid separation unit 4, the enzymatic hydrolysis unit 5, and the enzymatic hydrolysis liquid separation unit 6 are each an equipment structure that can be designed by those skilled in the art according to conventional means, and will not be described in detail here.

[0033] The key steps in the PHA preparation process are explained in detail below, and the other omitted parts are routine operations.

[0034] 1. Preparation of PHA fermentation broth:

[0035] Activation of bacterial strains: Transfer a ring of selected bacterial strains to the culture medium, culture it in a designated constant temperature incubator for a certain period of time, and use it as seeds for shake flasks.

[0036] Shake flask culture: Add a loop of the slant culture to a shake flask and culture it for a certain period of time, and use it as the first-level seed.

[0037] Seed tank culture: The seeds are placed in a graded seed fermentation tank (air sterilization) according to the process for expansion culture. Ventilated fermentation, after fermentation maturity, transfer to commercial tank.

[0038] Commercial fermentation tank: The seeds are placed in commercial fermentation tanks (not sterilized) for expansion culture according to the process. Hydrolyzed sugars and nitrogen sources are added according to the growth law of the bacteria during the fermentation process. Bacteria separation: washing by gravity centrifugation,

[0039] 2. PHA enzymatic separation:

[0040] Enzymatic hydrolysis: The separated bacteria are pumped into the enzymatic hydrolysis tank, the enzymatic hydrolysis temperature is maintained in the tank, and different enzymes are added according to the enzymatic hydrolysis process for enzymatic hydrolysis.

[0041] Enzymatic separation: Wash by gravity centrifugation and recover the enzymatic hydrolysate from the heavy phase by centrifugation.

[0042] PHA storage tank: The separated PHA emulsion is stored in the storage tank for buffering and backup.

[0043] 3. Plate and frame filter press: Use plate and frame to filter PHA emulsion, select filter cloth with air permeability, pressurize to 0.5-1.0Mpa for the first time and maintain for 1-2h, then pressurize to 0.8-1.5Mpa for the second time with air, blow for 15-30 minutes, pressurize PHA emulsion to 65-72% of dry matter and then discharge. Among them, the air permeability of the filter cloth is 20-300L / m 2 S (at 200P), preferably 150L / m 2 S (at 200P), the first pressurization is performed by a membrane filter press, model XAYG030-U; the second pressurization is performed by compressed air to increase the dry matter squeezed.

[0044] 4. Flash drying: 65%-72% of the filter cake after plate and frame filtration is dried to more than 99% of dry matter by flash drying.

[0045] Example

[0046] The cells fermented by halophilic bacteria are separated and washed, enzymatically hydrolyzed and washed with enzymatic solution to prepare PHA emulsion with dry matter content of 10%-30%. The emulsion is directly pressurized by plate and frame to form filter cake with dry matter content of 65%-72%. The emulsion is flash-dried to become qualified PHA finished product, which can be used for industrial production.

[0047]

[0048] The embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including combining various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A system for producing polyhydroxyalkanoates, characterized in that: The system comprises a fermentation unit (3), an enzymolysis unit (5), a plate and frame filter press (1) and a flash dryer (2) which are connected in sequence; wherein the plate and frame filter press (1) is arranged before the flash dryer (2), and the plate and frame filter press (1) comprises a filter frame, a filter plate and a filter cloth; the flash dryer (2) comprises a feeder, a stirring and crushing system, a classifier, a drying main pipe, a cyclone separator, a bag filter and a fan; the system is further provided with a fermentation liquid separation unit (4) after the fermentation unit (3) and before the enzymolysis unit (5); and an enzymolysis liquid separation unit (6) is provided after the enzymolysis unit (5) and before the plate and frame filter press (1).

2. The system according to claim 1, wherein: The filter cloth is pre-coated with a polyhydroxyalkanoate layer.

3. The system according to claim 1, wherein: The feeder is a cyclone feeder.

4. The system according to claim 2, wherein: The feeder is a cyclone feeder.

5. The system according to claim 1, wherein: The flash dryer (2) also includes an air filter.

6. The system according to claim 2, wherein: The flash dryer (2) also includes an air filter.

7. The system according to claim 3, wherein: The flash dryer (2) also includes an air filter.

8. The system according to claim 4, wherein: The flash dryer (2) also includes an air filter.

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