Hankinnan kuvaus
Primary use for the reactor is cellulose derivatization. The cellulose material to be mixed is mainly moist, sticky and fibrous, and the reactions will be done in high consistencies. ‘High-consistency’ refers to cellulose pulp, which contains even less than 70 % water. At this consistency, the pulp behaves almost like a solid and is challenging to mix. Thus special mixing elements such as shovels and chopper(s) are required. Mixing shovels are to enable complete mixing throughout the whole reactor volume, such as ploughshare shovels. Chopper is required to shred the cellulose material and ensure homogenous mixing conditions and that the mixed material is not only rotated around the reactor. The mixing elements should be able to disperse cellulose fibers but the mixing should not be so strong that it breaks the individual fibers. This is important when the desired product is surface-treated cellulose fibers, as opposed to ‘bulk treated’ cellulose, where the entire cellulose fiber structure is derivatized. Our goal is to be able to do both surface-treatments and bulk treatments.
Description of the process conditions:
— the cellulose pulp is mixed with additives, the reactor is heated to a desired temperature, derivatizing reagents are added, and the reaction is allowed to proceed,
— the main reaction solvent is tap water,
— heating is achieved by feeding steam into a jacket, which is around the reactor drum. In this document, the term ‘reactor drum’ refers to the part of the reactor where the mixing and reactions take place. For reactions that require higher pressures than what the solvent’s vapor pressure naturally induces in a given temperature, pressurized air will be used to increase the pressure in the drum. In exothermic reactions, the temperature might need to be lowered by feeding cold water into the jacket,
— afterwards, heating and lowered pressure will be used to dry the material.
Technical details for the reactor:
— reactor volume minimum 100 liters,
— the operational gauge pressure range of the reactor at least 0-10 bar,
— the operational temperature range at least 0-180 C,
— all rotating connections equipped with double mechanical seal,
— include minimum one chopper or similar homogenizing element(s),
— discharge valves must be operated by hydraulic, pneumatic, electric etc. non-manual means,
— dead volume of the discharge valve system should be minimized,
— feed and discharge valves must be equipped with safety device, which prevents opening while vessel is pressurized,
— for emptying and flushing purposes the main drive must be able to rotate while feed and discharge valves are open,
— The discharge valve must be located in the bottom of the reactor. Minimum distance between lowest point of discharge valve system and floor is 800 mm. This is not required if the reactor can be tilted to allow for draining of product efficiently,
— main drive and choppers motors controlled by frequency converter and adjustable via user interface,
— main drive power minimum 10 kW,
— main drive rotation speed minimum 150 rpm,
— chopper motor power minimum 5 kW,
— chopper rotation speed minimum 2 500 rpm,
— reactor drum, mixing element and heating jacket material AISI 316 L (1.4404),
— reactor is heated with steam and cooled with water. Steam generation unit is not included in the scope of supply. However, the heating/cooling jacket (all, if consists of multiple parts) must have connections at the lowest and highest point of the jacket,
— mixer is to include connection flanges that enable minimum five (5) connections for reagents and/or measurements.
Prize includes:
— described reactor system and supporting structure,
— control panel,
— shipping
— inspection for pressure vessel.
Additional information:
— equipment will be placed in non-ATEX area. Equipment does not need to be ATEX compatible,
— reactions will be done in mostly aqueous media,
— a used device is also acceptable if it fulfills the set criteria.