dry screw vacuum pump phenolic resin production

Why is the dry screw vacuum pump used in the production of phenolic resin?

Phenolic resin, many areas of the industry need to use this material for further processing. Chemical reaction needs to be completed in different size, different temperature, different pressure ratio of reaction equipment. Dry vacuum system is selected for the vacuum supply of 16 reactors in phenolic resin production company.

Phenolic resin can be used as adhesive for grinding wheel, non-woven fabric, filter paper and fire-resistant equipment. Phenolic resin can also be used to produce mineral wool, rock wool, decorative laminates and wooden derivatives.

In 16 reactors, about 150 different types of phenolic resins with sizes ranging from 4 to 32 cubic meters were produced by discontinuous production process. The processing time of each batch varies from 8 to 60 hours, and the reaction process will release heat and produce by-product water. In order to obtain different reaction temperature, vacuum is needed to reduce the boiling point of reaction mixture. When the boiling point is reduced, the water is removed from the reaction mixture at 40 ° C to 60 ° C during vacuum distillation. Because the process and raw material parameters of many products are different, and the reactor size is also different, the demand for vacuum is also very different. In order to capture the peak energy consumption, four surge tanks with a capacity of 43.5m3 are installed between the reactor and the vacuum system. The central vacuum system operates six days a week for 24 hours. The working pressure of the whole vacuum system is always between 50 and 60 mbar.

Why is the dry screw vacuum pump used in the production of phenolic resin?

Previously, the vacuum supply was provided by two rotary vane vacuum pumps, each of which required new oil lubrication at a pump speed of 1000 cubic meters per hour. A Roots vacuum pump with a pump speed of 2000 cubic meters per hour is also installed upstream of each pump to provide more pump pressure. This pump configuration does not guarantee trouble free production. The reason for these failures is that phenol and formaldehyde vapor will be inhaled, and they will condense and react in the compression chamber. This will cause phenolic resin particles and dust in the vacuum pump. These particles can only be washed out by new oil lubrication, and they will stick to the compression chamber of the rotary vane vacuum pump, resulting in shutdown. Theoretically, the chemical reaction in the vacuum pump is the same as that in the reactor. The filter installed downstream of the rotary vane vacuum pump is also prone to problems. The filter is mainly used to extract the oil sprayed as lubricating oil. The liquid formed by steam combination of oil with phenol and formaldehyde will completely block the filter assembly. This means that the filter assembly replacement interval will be very short, only one to two weeks.

Therefore, it is recommended that the system consists of two screw vacuum pumps (400 m3 / h) and one roots vacuum pump (2000 m3 / h). The control system of the vacuum system has been specially designed to achieve the speed of the system. The volume of the vacuum pump is larger, but the unit is smaller, so it can save a lot of energy. The connection power of the previous pump station was 41 kW. And the vacuum system only needs 27.5kw, saving more than 30% energy. The pump station operates completely in a dry environment, which means that oil is no longer needed in the compression chamber. As a result, there is no need to use an oil separator downstream, saving oil and the cost of removing old oil and clogging the filter.

The system complies with ATEX (ex II 2G IIB T3) standard. The internal area is zone 1; the external area and the area around the vacuum pump are not set. However, the process is only related to ATEX in the start-up phase, as solvent vapor may be present in the system. Under any condition, the system does not work itself in the start-up phase, and there is no explosion risk after that.

Phenolic resin produces dry screw vacuum pump and roots vacuum pump. After the vacuum system is commissioned and put into use, there has never been any work failure, and the maintenance workload is greatly reduced. The vacuum system will be repaired and inspected once a year. Change the oil for gear set in vacuum pump, and the work shall be carried out by internal staff.