Stainless steel reactor, continuous

The nitrating acid is, just like a hundred years ago, a mixtiue of nitric and sulfuric acid and water (normally 21.4 66.4 12.2). The ratio may be changed according to the DS and the properties desired. A large excess of acid (20 1-50 1) is used to keep the reaction mixture stirrable. The reaction runs at 10-36 °C for 30 min. in stainless-steel reactors. Continuous processes are known and practiced. After the reaction, the acid is centrifuged off. Further steps deal with the fast and complete elimination of the acid from the product because acids reduce quality and yield by degradation and hydrolysis. 

Two types of reactors were used One was a CSTR type consisting of an Y2O3 (8mol%)-stabilized Z1O2 (YSZ) tube (length 15 cm, diameter 2 cm) closed flat at one end with an appropriately machined water-cooled stainless steel reactor cap attached to the other end, thus allowing for continuous gas feed and... 

The reactor assembly was heated by electric heaters. The maximum operating temperature Is determined by the window construction. Sapphire windows (from EIMAC), brazed into Kovar sleeves, were used the sleeves were then welded directly into the stainless steel reactor housing. We found that the cell so constructed was capable of trouble-free, continuous operation at 450°C operations at somewhat higher temperatures are probably still possible but were not explored. Sapphire was chosen as a window material because it is insensitive to water vapor and is transparent in tljie wave number range of our interest (about 2400 cm to 2000 cm in these experiments). Moreover, the thermal expansion characteristics of the reactor were found to match well with those of the window fixture. 

These experiments have been performed in a classical fixed bed continues flow reactor system [5]. The catalyst sample (0.2 g) diluted with SiC was charged in a 12.6 mm i.d. tubular stainless-steel reactor, between two layers of SiC. The thermocouple well was placed in the axis of the reactor. The various CsHj - O2 - N2 mixtures were prepared by means of mass flow controllers and the concentrations of products were determined by gas chromatography, using PORAPAK Q columns (2 m 1/8") for preliminary separation and CARBOXEN 1000 column (4m 1/8") for O2, N2, CO, CO2 and an other PORAPAK Q column (2 m 1/8") for CsHg and C3H6. 

Several post irradiation material tests and in-pile creep tests on FBR grade 316 stainless steel were continued in Joyo and JMTR (Japan Material Test Reactor of JAERI) in accordance with the R D program Spica step-2. 

In a modified suspension polymerization, the pressure requirements are reduced. The reaction is conducted with azo catalysts (75) at 25-100°C and pressures of 2.5-10 MPa (25-100 atm) over 18-19 h. A stainless steel reactor is flushed with nitrogen charged with 150 parts acetylene-free VF, 150 parts deoxygenated distilled water, and 0.150 parts 2,2 -azobisisobutyronitrile. The reactor is heated to 70°C for 1 h, agitated, and held at 8.2 MPa (82 atm) for 18 h. The product, 75.8 parts of PVF, is collected in the form of a white cake (64). Continuous polymerization of VF is based on the modified suspension process (76). 

Batch extraction of destarched wheat bran was carried out on 2.2 kg of vegetable matter under continuous stirring in an SOL stainless steel reactor devoid of any heating or cooling device. 

A typical polymerization run was conducted in a stirred one-gallon (3.7 liters) stainless steel reactor equipped with baffles and a cooling coil, rated at 69 MPa. The vessel was charged with 2,470 ml of water, 908 g of vinylidene fluoride, 30 g of an aqueous methyl hydroxypropyl cellulose solution, and 5 g of tert-butyl peroxypivalate. Water pressure was raised to 5.5 MPa at 25°C under which the liquid monomer density is 0.69 g/ml. The reactor was heated to 55°C, increasing the pressure to 13.8 MPa. The reaction was continued for four hours during which 800 ml of water was pumped into the vessel to keep the pressure constant. 

Monomer emulsions ate prepared in separate stainless steel emulsification tanks that are usually equipped with a turbine agitator, manometer level gage, cooling cods, a sprayer inert gas, temperature recorder, mpture disk, flame arrester, and various nossles for charging the ingredients. Monomer emulsions are commonly fed continuously to the reactor throughout the polymerisation. 

A hst of polyol producers is shown in Table 6. Each producer has a varied line of PPO and EOPO copolymers for polyurethane use. Polyols are usually produced in a semibatch mode in stainless steel autoclaves using basic catalysis. Autoclaves in use range from one gallon (3.785 L) size in research faciUties to 20,000 gallon (75.7 m ) commercial vessels. In semibatch operation, starter and catalyst are charged to the reactor and the water formed is removed under vacuum. Sometimes an intermediate is made and stored because a 30—100 dilution of starter with PO would require an extraordinary reactor to provide adequate stirring. PO and/or EO are added continuously until the desired OH No. is reached the reaction is stopped and the catalyst is removed. A uniform addition rate and temperature profile is required to keep unsaturation the same from batch to batch. The KOH catalyst can be removed by absorbent treatment (140), extraction into water (141), neutralization and/or crystallization of the salt (142—147), and ion exchange (148—150). 

Hydrogenations can be carried out in batch reactors, in continuous slurry reactors, or in fixed-bed reactors. The material of constmetion is usually 316 L stainless steel because of its better corrosion resistance to fatty acids. The hydrogenation reaction is exothermic and provisions must be made for the effective removal or control of the heat a reduction of one IV per g of C g fatty acid releases 7.1 J (1.7 cal), which raises the temperature 1.58°C. This heat of hydrogenation is used to raise the temperature of the fatty acid to the desired reaction temperature and is maintained with cooling water to control the reaction. 

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