The Energy Consumption Reduction Technology in Industrial Xanthan Gum Jelly Production

Xanthan gum made from corn is a microbial extracellular polysaccharide obtained by biological fermentation with corn starch as the main raw material. It has unique thickening, rheological properties and good compatibility with salts. It is an application of production technology A wide range of fermented products, with applications covering more than 20 industries.

Ⅰ. The production process of xanthan gum

Xanthan gum mainly uses corn starch as a carbon source, fish meal and soybean meal powder as a nitrogen source, and a fermentation temperature of (28±1) C. After 45-72 hours of fermentation with a certain amount of ventilation controlled, the mass fraction of the fermentation broth reaches 2.5. %—3.5%.

After the fermentation broth is concentrated, a certain proportion of ethanol is added to precipitate xanthan gum from the solution. The xanthan gum solid is obtained by solid-liquid separation. Then a certain amount of ethanol is added for washing (to remove impurities and pigments further), solid-liquid After separation, the final xanthan gum solids are dried, crushed, classified, inspected and packaged.

The low-alcohol liquid (waste liquor) obtained by the secondary solid-liquid separation can be rectified and recovered. The tower top (ethanol) product is recycled. The bottom still liquid is discharged after environmental protection treatment.

Ⅱ. Energy-saving and consumption-reducing technologies of xanthan gum producers

1. High-efficiency and low-resistance air purification technology

The main purpose of the air purification system is to degrease, dehumidify and sterilize the air to meet the needs of the fermentation system. The system includes air storage tanks, air coolers, air-water separators, air heaters and air filters, among which air coolers and filters are two key devices that affect the system's resistance.

2. Air-lift fermenter replaces traditional mechanical agitated fermenter

At present, the fermentation tanks of various manufacturers are traditional mechanical agitation, which consumes a lot of power. In the later stage of fermentation, the viscosity of the fermentation liquid is high, resulting in poor gas-liquid-solid mass transfer, low air utilization, imperfect fermentation, and a long fermentation cycle. Most Chinese xanthan gum producers use small-volume fermentation tanks, generally 30-40 m³, with a maximum of 60m³. To solve the energy consumption problem, the air-lift fermentation tank is a good replacement structure.

3. Concentrated treatment technology of xanthan gum solution

The large consumption of ethanol is one of the main reasons for the high extraction cost of xanthan gum (accounting for more than 50% of the total production cost). Since the amount of solvent used in the precipitation operation has nothing to do with the concentration of the solution, only the volume of the resolution, the ethanol precipitation method is used to extract xanthan gum. To reduce the amount of solvent used, it is best to increase the concentration of the xanthan gum solution and reduce the fermentation broth. 

Some researchers have used ultrafiltration methods to increase the concentration of xanthan gum solutions and have achieved good laboratory results. However, this method is still at the laboratory level due to membrane products' performance, quality, and operating costs, with no industrial application.

4. Ethanol recovery technology

The efficiency of ethanol recovery determines the consumption of ethanol and the production cost of the product. Traditional distillation is used for the recovery of waste liquor. Since many solids are left in the waste liquor during xanthan gum precipitation, most xanthan gum producers use plate towers to avoid tower blockage affecting the operation of the tower.