JPH054128B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Application Field) The present invention prevents powder particles from adhering to and growing on a spray nozzle and its supply pipe provided in a spray chamber of a continuous fluidized bed granulator. It is about the method.

(Prior art) A fluidized bed granulator is equipped with a spray nozzle in a fluid chamber, and is used to collect powdered or granular pharmaceuticals, foods, etc.
Feed etc. is made into a fluid state and a binder solution is sprayed onto it to agglomerate the powder or granules, or the granules are made into a fluid state and a coating agent solution is sprayed onto this to coat the surface of the granules. It covers the These operations proceed while the sprayed solution is evaporated and dried. The evaporation rate of the sprayed solution is determined by the supply conditions of hot air, the rate of the sprayed liquid such as the binder solution, and the heat capacity coefficient of the device, and the solution that is not completely evaporated penetrates into the powder and increases its moisture content. Therefore, the atmosphere within the fluidized bed is humidified and cooled to almost the wet bulb temperature of the hot air, and the relative humidity often reaches around 100% RH. The spray nozzle is installed in this kind of atmosphere,
Moreover, since the solution and atomizing air at a temperature lower than the hot air temperature are supplied to the spray nozzle, water vapor may condense on its surface, or the sprayed solution may bounce and adhere to the spray nozzle, resulting in a wet state. Become.

The surrounding powder and granules then adhere to it. This deposit gradually grows and becomes a clump-like deposit, eventually making normal atomization impossible. This phenomenon also occurs with the piping that supplies atomizing air, binder solution, etc. to the spray nozzle, and deposits on these pipes become wet because there is no time to wash them during continuous operation. This is undesirable from a sanitary point of view, as it tends to become a source of bacterial growth. Conventionally, there was no means to prevent condensation on the supply pipe, and in order to reduce the splashing of sprayed droplets, air nozzles were arranged around the liquid nozzle to reduce the amount of liquid to be sprayed that was sprayed from the liquid nozzle. Atomizing air is injected so as to envelop the liquid, and the liquid and air are mixed outside the nozzle.
The problem has been dealt with by using an external mixing nozzle that atomizes, and by interrupting operation at regular intervals to replace or clean the nozzle. However, these methods are a major cause of limiting continuous operation time, and the external mixing nozzle with the above structure cannot maintain a large relative velocity between the liquid and air, and therefore, the liquid and air inside the nozzle are mixed. This method has the disadvantage that considerably more atomizing air is required to obtain the same droplet size, compared to the case of using an internal mixing nozzle that atomizes by colliding air.

(Problem to be solved by the present invention) The problem to be solved by the present invention is to prevent powder particles from adhering to and growing on the spray nozzle and its supply pipe provided in the spray chamber of a continuous fluidized bed production device. The goal is to provide a new method.

(Means for Solving the Problems) The means of the present invention for solving the above problems is to control the surface temperature of at least one of the atomizing nozzle and the supply pipe of the atomizing air or the liquid to be sprayed in a continuous fluidized bed granulation device. , the dew point temperature in the injection chamber is set at least 20°C higher.

The present invention heats the atomizing nozzle and the piping up to the atomizing nozzle by preheating the atomizing air supplied to the nozzle or both the atomizing air and the liquid to be atomized.
The temperature is kept at least 20°C higher than the fog point temperature in the spray chamber to prevent water vapor from condensing on the surface, and when droplets adhere to it, they quickly evaporate to keep the surface dry. In addition to the external mixing nozzle, it is also possible to use an internal mixing nozzle with low air consumption. It is something.

(Examples) Hereinafter, the present invention will be specifically described based on illustrated examples.

In the figure, numeral 1 is a fluidized tank, 2 is a spray chamber, 3 is a dust collection chamber, and 4 is a gas supply chamber. These are similar to conventional continuous fluidized bed granulators of this type, and are formed in the shape of an inverted truncated cone, and the bottom surface 6 is formed by a ventilation disc. Further, a hot air supply duct 5 is connected to the gas supply chamber 4, and is configured to blow up hot air at an appropriate temperature into the fluidized fluidized tank 1. The spray chamber 2 is an area for spraying a binder or a coating agent on the powder and granules forming a fluidized bed in the fluidized tank 1, and is equipped with a spray nozzle 7 facing the fluidized bed. A supply duct 10 is installed. The dust collecting chamber 3 is for collecting powder particles that fly up as fine powder, and a bag filter 8 is attached thereto. Although not shown, the exhaust duct 9 is equipped with a flow rate regulating damper as well as a detector for detecting temperature or humidity.
This allows the temperature and humidity of the hot air supplied from the hot air supply duct 5 to be controlled. Reference numeral 11 is a take-out port through which granulated or coated granules are continuously taken out of the machine. A continuous dryer 16 is installed at the outlet 11.
is connected, and the granules discharged from the outlet 11 are supplied to a continuous dryer 16. Here, the continuous dryer 16 is not particularly limited. In short, any material that can dry the granules continuously is sufficient. The figure shows a horizontal continuous fluidized bed dryer as an example, and the outlet 11 is connected to the fluid chamber 18 of the continuous dryer 16 via a screw conveyor 17, and the granules are removed from the outlet 11. Immediately after being discharged, the flow chamber 18
The hot air blows up from the ventilation panel 19 to dry the air, and then it is discharged from the outlet 20.

The atomizing air or the atomizing air and the liquid to be atomized to be supplied to the atomizing nozzle 7 of the continuous fluidized bed granulator configured in this manner are preheated, and the surface of the atomizing nozzle 7 and its supply pipe 12 is heated by this heat. The temperature is heated to 20°C or more higher than the dew point temperature inside the spray chamber.
The supply pipe 12 consists of an air supply pipe 13 and a liquid supply pipe 14. Although not shown, the air supply pipe 13 is connected to a compressor to supply compressed air to the spray nozzle 7, and the liquid supply pipe 14 is connected to the sprayed liquid tank directly or via a liquid supply pump. The liquid to be sprayed is supplied to the spray nozzle 7. A heat exchanger 15 is installed in the middle of the air supply pipe 13 to heat the air in the pipe, and if necessary, a heat exchanger is installed in the middle of the liquid supply pipe 14 to heat the liquid to be sprayed in the pipe. I'm starting to do that.

(Function) In order to prevent powder from adhering to the spray nozzle 7 and the supply pipe 12 in the continuous fluidized bed granulator configured in this way, the heat exchanger 15 is operated to heat the atomizing air. Then, if necessary, the liquid to be sprayed is heated, and the spray nozzle 7 and supply pipe 1 are heated by this heat.
2 is heated to perform granulation and coating operations continuously. In this case, the dew point temperature in the spray chamber 2 during fluidized bed granulation is generally 30 to 45°C, so if the surface temperature of the spray nozzle 7 and supply pipe 12 is at least this temperature or higher, wetting due to dew condensation can be avoided. can be prevented. Furthermore, if the surface temperature is set to about 20°C or more higher than the dew point temperature, it will prevent the surface of the spray nozzle from getting wet due to the splashing of spray droplets, and will suppress the adhesion and growth of powder particles. The temperature was set to 20°C or more above the dew point.

(Effects of the Invention) That is, by doing this, water vapor does not condense on the spray nozzle and the supply pipe 12, and the solution that adheres to it due to splashing etc. dries quickly, so that the powder and granules are free from condensation. Reduces adhesion and inhibits its growth. As a result, the atomizing nozzle guarantees atomizing performance over a long period of time and reduces the proportion of lumps mixed into the product due to poor atomization. In addition, by preventing the formation of wet deposits on the spray nozzle and supply pipe, the possibility of bacterial growth in these areas is reduced, and the cleaning cycle of the spray nozzle, etc. can be extended. Continuous operation becomes possible.

Furthermore, it has become possible to apply an internal mixing nozzle, which was considered difficult to apply to fluidized bed granulation equipment due to the greater possibility of splashing of the sprayed droplets compared to conventional external mixing nozzles. The amount of oxidized air consumed can be reduced to about half, and operating costs can be reduced. In addition, in the case of a batch type fluidized bed granulator, the nozzle can be replaced and cleaned every time, so this method is not as effective in terms of cost performance as the continuous type, but it has the same effect. Of course there is.

[Brief explanation of the drawing]

The figure is a schematic diagram showing one embodiment of the present invention. 1; Fluidization tank, 2; Spray chamber, 3; Dust collection chamber, 4; Gas supply chamber, 5; Hot air supply duct, 6; Bottom surface, 7;
Spray nozzle, 8; bag filter, 9; exhaust duct, 10; supply duct, 11; outlet, 12; supply pipe, 13; air supply pipe, 14; liquid supply pipe, 15;
Heat exchanger.

Claims (1)

[Claims] 1. A continuous fluidized bed granulator, characterized in that the surface temperature of at least one of the spray nozzle and the supply pipe for the atomizing air or the liquid to be sprayed is set to be 20°C or more higher than the dew point temperature of the spray chamber. A method for preventing powder from adhering to a spray device in a continuous fluidized bed granulation device.