Design Of Gas Valve Array For Beer Fermentation

With the development of industrial automation, it is a general trend for beer production automation to replace manual operation. This paper combines the actual needs of a brewery's fermentation process and designs a fermentation gas valve array to replace the traditional gas pipe array, providing a reference for related industries.

1. Traditional Fermentation Gas Pipe Row

The traditional fermentation gas pipe arrangement is equipped with CIP liquid supply pipe, compressed air pipe, CO2 gas supply pipe, CO2 recovery pipe, exhaust gas discharge pipe and tank top connecting pipe. Each fermentation tank is equipped with a pressure regulating valve, and each gas pipe corresponds to a manual valve, which is realized by manual switching.

From the time the wort enters the tank to the time the fermentation tank is cleaned, it is necessary to manually switch the switch many times and set the pressure value of the pressure regulating valve. This increases the labor intensity of on-site operations and is also prone to operating errors. For example, compressed air entering the CO2 recovery pipeline leads to insufficient purity of the recovered CO2, and compressed air entering the mature fermentation liquid storage tank leads to high dissolved oxygen quality problems. For this reason, it is necessary to solidify the workflow through automated operations and introduce automated valves to replace manual operations.

2. Valve selection

Automated valves include pneumatic butterfly valves, anti-mixing valves, pneumatic stop valves, pneumatic regulating valves, etc. Considering that gas pipes need to switch pipeline operations, pneumatic butterfly valves and anti-mixing valves are generally selected. In terms of the selection of anti-mixing valves, it is necessary to make subdivisions and selections based on the pressure requirements of the gas pipe working conditions. Generally, for pipelines with large diameters, high pressures, and prone to water hammer, double-seat double-seal anti-mixing valves (referred to as double-seat anti-mixing valves) can be selected, while for pipelines with small diameters and low pressures, single-seat double-seal anti-mixing valves (referred to as single-seat anti-mixing valves) are more cost-effective.

3. Gas pipe valve array design

The valve array system is a valve array composed of several valves and pipelines. By controlling the inlet and outlet switches of the valves, the conversion of conveying different materials and other special functions can be achieved.

Compared with the traditional manual gas pipe array, this design uses a valve array to achieve automated operation and optimizes the gas pipeline configuration in the fermentation area in combination with actual process requirements. On the one hand, since compressed air is first used to replace the CO2 in the fermentation tank before alkali washing, and then the tank body is cleaned, the compressed air supply pipe can share the same pipeline with the CIP liquid supply pipe; on the other hand, since the pressure requirements in the middle and late stages of fermentation are higher than those in the early stages of fermentation, two CO2 recovery pipelines with different working conditions can be configured to balance the pressure in the fermentation tank, while also saving the cost of the pressure regulating valve. Table 2 shows the configuration of the fermentation gas pipe array.

Table 2 Fermentation gas pipe arrangement configuration

Because the fermentation tank is cleaned by tank washer, the pressure requirement of CIP liquid supply pipe is relatively high, while the gas pipe is used for gas transportation in the fermentation process, and the working pressure is relatively low. Therefore, the liquid supply pipe adopts double-seat anti-mixing valve. The gas pipe adopts single-seat anti-mixing valve to reduce costs.The CIP liquid supply pipe is connected to the lower valve chamber of the double-seat anti-mix valve, and the tank top connecting pipe is connected to the upper valve chamber of the double-seat anti-mix valve. During cleaning, the cleaning liquid flows from the lower valve chamber to the upper valve chamber. At the end of cleaning, the anti-mix valve is "backflow closed" to avoid water hammer.

Similarly, in the connection between the compressed air pipe and the CIP liquid supply pipe, the compressed air should be designed to supply air from the lower valve cavity to the upper valve cavity, otherwise the "downstream closing" is prone to air hammer. At this time, the CIP liquid supply pipe should be connected to the upper valve cavity of the double-seat anti-mix valve, and the compressed air pipe should be connected to the lower valve cavity of the double anti-mix valve.

In terms of connecting the tank top connecting pipe with other gas pipelines, the tank top connecting pipe is connected to the upper part of the single-seat anti-mixing valve, and the gas pipe row is connected to the bottom of the single-seat anti-mixing valve.

Finally, considering that cleaning liquid will remain in the tank top connecting pipe after the fermentation tank is cleaned, a liquid level detection switch can be configured at the low position of the pipeline to automatically control the switch state of the discharge valve. The liquid level detection switch also has a leakage protection function: if the gas pipeline needs to be CIP regularly, considering the water hammer impact in extreme cases, the single-seat anti-mixing valve is lifted up, and the CIP liquid is mixed into the upper tank top pipeline. At this time, the liquid level detection switch at the low position of the pipeline can control the discharge valve to open to prevent the CIP liquid from entering the tank body.