Recovery device for residual solvent in stevioside residues

Abstract

The utility model belongs to the technical field of stevioside production, and discloses a device for recovering a residual solvent in stevioside residues, which comprises a stock bin, a discharge port of the stock bin is communicated to a feed port of a dryer, and an air outlet of the dryer is communicated to an air inlet of a tower kettle through a pipeline; a gas outlet is formed in the top of the tower kettle, the gas outlet is sequentially communicated with a cooler and a condenser through a pipeline, a discharge port of the condenser is communicated with a material transfer pump, an outlet of the material transfer pump is respectively communicated with a solvent discharge pipe and a solvent return pipe, a solvent switch valve is arranged on the solvent discharge pipe, and a first densimeter and a return regulating valve are arranged on the solvent return pipe; a liquid outlet is formed in the bottom of the tower kettle, a circulating pump, a second densimeter and a tee joint are sequentially arranged on a liquid conveying pipeline communicated with the liquid outlet, and the tee joint is communicated to the upper part of the tower kettle through a rectification regulating valve and is communicated to an extracting solution storage tank through a rectification discharging switch valve. According to the utility model, the residual solvent in the stevioside residue can be recycled, so that the effects of saving energy and improving efficiency are achieved.

Description

Technical Field

[0001] The utility model belongs to the technical field of stevioside production, and in particular relates to a device for recovering residual solvent in stevioside residue. Background Art

[0002] Stevioside is extracted from the leaves of stevia, which are mainly composed of water and dry matter. The main component of the dry matter is stevioside, which accounts for about 10% of the dry matter. Since stevioside is easily soluble in water and alcohols, the existing production process generally selects ethanol as a solvent to extract stevioside from stevia leaves. The residue after extraction enters the drying process after extrusion. However, the residue after extrusion still contains some unrecovered solvent (ethanol), which will be wasted in the subsequent drying, causing economic losses to the production enterprise. In order to reduce this loss, all the solvents are recovered and purified to a degree that can be reused, and the economic benefits are improved, it is necessary to design a set of residual solvent recovery equipment in the residue. Summary of the invention

[0003] The technical problem to be solved by the utility model is to provide a residual solvent recovery device in stevia residue, which can recover the residual solvent in the stevia residue after being squeezed out, so as to achieve the effect of energy saving and efficiency improvement.

[0004] In order to solve the above technical problems, the technical solution of the utility model is:

[0005] A device for recovering residual solvent in stevia residues comprises a silo, the discharge port of the silo is connected to the feed port of a dryer, the air outlet of the dryer is connected to the air inlet of a tower kettle through a pipeline; the lower part of the tower kettle is arranged as a liquid storage chamber, and the upper part is filled with a plurality of filler layers (stainless steel orifice plate corrugated filler: advantages: anti-pollution: because the free cross section is large and the flow film is more uniform, it is not more polluted than other fillers. Slight surface attachments generally do not affect the efficiency. If the gas contains some plant volatile colloids, it will not block the tower body); the top of the tower kettle is provided with an air outlet, and the air outlet is connected to the tower kettle through a pipeline; the lower part of the tower kettle is provided with ... of the tower kettle is provided with a plurality of filler layers (stainless steel orifice plate corrugated filler: advantages: anti-pollution: because the free cross section is large and the flow film is more uniform, it is not polluted than other fillers. Slight surface attachments generally do not affect the efficiency. If the gas contains some plant volatile colloids, it will not block the tower body); the upper part of the tower kettle is provided with an air outlet, and the air outlet is connected to the tower kettle through a pipeline; the lower part of the tower kettle is provided with an air outlet, and the upper part of the tower kettle is provided with an air outlet, and the upper part A cooler and a condenser are connected in sequence through pipelines, a discharge port of the condenser is connected with a transfer pump, and the outlet of the transfer pump is respectively connected with a solvent discharge pipe and a solvent reflux pipe; a solvent switch valve is provided on the solvent discharge pipe, and a first density meter and a reflux regulating valve are provided on the solvent reflux pipe; a liquid outlet is provided at the bottom of the tower kettle, and a circulation pump, a second density meter and a tee are sequentially provided on the liquid infusion pipeline connected to the liquid outlet, and the tee is also connected to the upper part of the tower kettle through a distillation reflux pipeline and a distillation regulating valve, and is connected to the extract storage tank of the previous process through a residual liquid output pipeline and a distillation discharge switch valve.

[0006] Preferably, the dryer is a disc dryer, in which a steam heating coil is provided in the inner cavity of the disc dryer, and a plurality of layers of baking trays are provided, a material discharge port is provided in the center of the baking tray, a stirring shaft is inserted through the center of the material discharge port, and a plurality of rake teeth fixedly connected to the stirring shaft are provided on the upper part of each baking tray, and the relatively arranged rake teeth are outward rake teeth and inward rake teeth respectively.

[0007] Furthermore, the upper part of the steam heating coil in the disc dryer is connected to the steam input device, and the bottom outlet is connected to the condensed water tank; the bottom of the disc dryer is provided with a discharge port, and a rotary valve is provided at the discharge port. The rotary valve outputs the dried slag particles to the slag storage tank.

[0008] The model of the disc dryer is PLG-3000, manufacturer: Changzhou Yusheng Drying Technology Co., Ltd.

[0009] Preferably, a liquid level sensor is provided on the side wall of the lower part of the tower kettle.

[0010] Preferably, the packing layer in the tower bottom is provided with 6 layers.

[0011] Preferably, the cooler and the condenser are both provided with an ice water inlet and an ice water outlet, and heat exchange is performed by ice water.

[0012] The heat exchange area of ​​the cooler and condenser is 20㎡. Manufacturer: Shandong Haomai Machinery Manufacturing Co., Ltd.

[0013] Preferably, the material transfer pump is interlocked with the solvent switch valve, the first density meter and the reflux regulating valve. The material transfer pump, the solvent switch valve, the first density meter and the reflux regulating valve are all electrically connected to a DCS automatic control system.

[0014] Preferably, the circulation pump, the second density meter, the distillation regulating valve and the distillation discharge switch valve are interlocked with each other. The circulation pump, the second density meter, the distillation regulating valve and the distillation discharge switch valve are all electrically connected to a DCS automatic control system.

[0015] The transfer pump and circulation pump are both centrifugal pumps, manufactured by Wenzhou Kangerda Pump Industry Co., Ltd.; the first density meter and the second density meter are both KDM-05 series density meters produced by Qingdao Aowei Fluid Metering Co., Ltd.; the reflux control valve and the distillation control valve are both pneumatic diaphragm control valves, which are the K200 series control valves of Austell Control Valve (Shanghai) Co., Ltd.; the solvent switch valve and the distillation discharge switch valve are both pneumatic ball valves, which are the K400 series switch ball valves of Austell Control Valve (Shanghai) Co., Ltd.

[0016] Due to the adoption of the above technical solution, the beneficial effects of the utility model are:

[0017] The utility model uses a dryer to dry the stevia residue after squeezing, and transports the solvent-containing steam generated in the drying process to the tower kettle. After passing through the filler in the tower kettle (the function of the filler is to allow the water droplets falling from the distillation tower to fully contact with the incoming steam, so that the solvent in the droplets is fully heated and evaporated again), it enters the cooler and the condenser in sequence to become liquid, and then the density of the liquid is continuously detected by a first density meter, and the density is used to determine whether the liquid is refluxed into the tower kettle to continue to concentrate the solvent, or to obtain a qualified high-concentration solvent for extraction; the circulating pump is turned on after the bottom feed liquid of the tower kettle reaches a certain liquid level, and when the second density meter detects that the bottom feed liquid reaches the specified density, the distillation regulating valve is closed, the distillation discharge valve is opened, the bottom feed liquid starts to be discharged, and the bottom feed liquid returns to the extraction liquid storage tank of the previous process for extraction.

[0018] In short, the utility model can recycle the residual solvent in the stevia residue after squeezing out, so as to achieve the effect of energy saving and efficiency improvement. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the structure of the utility model;

[0020] Figure 2 It is a structural schematic diagram of a drying plate and rake teeth in the utility model drying machine;

[0021] In the figure, 1, silo; 2, dryer; 21, baking tray; 211, discharge port; 22, stirring shaft; 221, outward rake teeth; 222, inward rake teeth; 3, tower bottom; 4, cooler; 5, condenser; 6, material transfer pump; 7, solvent switch valve; 8, first density meter; 9, reflux regulating valve; 10, circulation pump; 11, second density meter; 12, distillation regulating valve; 13, distillation discharge switch valve. DETAILED DESCRIPTION

[0022] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0023] Embodiment 1:

[0024] like Figure 1 and Figure 2As shown, a residual solvent recovery device in stevia residue includes a silo 1, a discharge port (not marked) arranged at the bottom of the silo 1 is connected to a feed port (not marked) arranged at the top of a dryer 2, and an air outlet (not marked) arranged at the top of the dryer 2 is connected to an air inlet of a tower kettle 3 through a pipeline; the lower part of the tower kettle 3 is arranged as a liquid storage chamber (not marked), and the upper part is filled with 6 layers of packing layers (not marked); the top of the tower kettle 3 is provided with an air outlet (not marked), and the air outlet is sequentially connected to a cooler 4 and a condenser 5 through a pipeline, and the discharge port of the condenser 5 is connected to a transfer pump 6, and the outlet of the transfer pump 6 A solvent discharge pipe (not marked) and a solvent reflux pipe (not marked) are respectively connected; a solvent switch valve 7 is provided on the solvent discharge pipe, and a first density meter 8 and a reflux regulating valve 9 are provided on the solvent reflux pipe; a liquid outlet (not marked) is provided at the bottom of the tower kettle 3, and a circulating pump 10, a second density meter 11 and a tee (not marked) are sequentially provided on the liquid infusion pipeline connected to the liquid outlet, and the tee is also connected to the upper part of the tower kettle 3 through a distillation reflux pipe (not marked) and a distillation regulating valve 12, and is connected to the extract storage tank (not marked) of the previous process through a residual liquid output pipe and a distillation discharge switch valve 13.

[0025] The dryer 2 is a disc dryer, in which a steam heating coil (not shown) is arranged in the inner cavity of the disc dryer, and a six-layer baking tray 21 is also arranged. A discharge port 211 is arranged in the center of the baking tray 21, and a stirring shaft 22 is inserted through the center of the discharge port 21. Two pairs of rake teeth (not shown) arranged opposite to each other and fixedly connected to the stirring shaft 22 are arranged on the upper part of each baking tray 21. The oppositely arranged rake teeth are respectively outward rake teeth 221 and inward rake teeth 222.

[0026] In actual use, the stevia residue after the slag is squeezed out in the previous process is first transported into the silo 1, and then enters the dryer 2 under the action of the rotary valve provided at the bottom of the silo 1. Under the drying action of the steam coil provided in the dryer 2, the solvent and part of the water in the residue evaporate and enter the tower kettle 3. After the steam passes through the separation action of the filler (a part of it becomes liquid and drips into the liquid storage cavity at the bottom of the tower kettle 3), the gas is transported to the cooler 4 and the condenser 5 in turn to be condensed into liquid. The liquid flows back to the top of the tower kettle 3 through the transfer pump 6 connected to the bottom of the condenser 5 for circulation and concentration. The temperature at the top of the tower is controlled at 80°C (to ensure that the ethanol in the liquid can be quickly discharged). The first density meter 8 is used to detect the density of the liquid in real time. When the density of the liquid reaches the specified concentration (that is, the solvent is concentrated to the qualified concentration), the reflux regulating valve 9 is closed, and the solvent switch valve 7 is opened to extract the solvent of the qualified concentration; when the bottom liquid of the tower kettle 3 reaches a certain liquid level, the circulation pump 10 is turned on. When the second density meter 11 detects that the bottom liquid has reached a specified density (about 0.2g / ml, and the waste liquid contains water, stevioside and other residue extrudates), the distillation regulating valve 12 is closed, and the distillation discharge switch valve 13 is opened to output the concentrated bottom liquid and transport it to the extraction liquid storage tank of the previous process for further extraction.

[0027] It should be understood that these embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the claims attached to this application.

Claims

1. A device for recovering residual solvent in stevia residue, characterized in that: It includes a silo, the discharge port of the silo is connected to the feed port of the dryer, and the air outlet of the dryer is connected to the air inlet of the tower kettle through a pipeline; the lower part of the tower kettle is set as a liquid storage chamber, and the upper part is filled with several layers of packing layers; the top of the tower kettle is provided with an air outlet, and the air outlet is connected to a cooler and a condenser in sequence through pipelines, the discharge port of the condenser is connected to a transfer pump, and the outlet of the transfer pump is respectively connected to a solvent discharge pipe and a solvent reflux pipe; a solvent switch valve is provided on the solvent discharge pipe, and a first density meter and a reflux regulating valve are provided on the solvent reflux pipe; the bottom of the tower kettle is provided with a liquid outlet, and a circulation pump, a second density meter and a tee are sequentially provided on the liquid infusion pipeline connected to the liquid outlet, and the tee is also connected to the upper part of the tower kettle through a distillation reflux pipeline and a distillation regulating valve, and is connected to the extract storage tank of the previous process through a residual liquid output pipeline and a distillation discharge switch valve.

2. The device for recovering residual solvent in stevia residue according to claim 1, characterized in that: The dryer is a disc dryer.

3. The device for recovering residual solvent in stevia residue according to claim 1, characterized in that: A liquid level sensor is arranged on the side wall of the lower part of the tower kettle.

4. The device for recovering residual solvent in stevia residue according to claim 1, characterized in that: The packing layers in the tower kettle are provided with 6 layers.

5. The device for recovering residual solvent in stevia residue according to claim 1, characterized in that: The material transfer pump is interlocked with the solvent switch valve, the first density meter and the reflux regulating valve.

6. The device for recovering residual solvent in stevia residue according to claim 1, characterized in that: The circulation pump, the second density meter, the distillation regulating valve and the distillation discharge switch valve are interlocked with each other.

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