Reactor Steel

In a typical adiabatic polymerization, approximately 20 wt % aqueous acrylamide is charged into a stainless steel reactor equipped with agitation, condenser, and cooling jacket or coils. To initiate the polymerization, an aqueous solution of sodium bisulfite [7631-90-5] is added, followed by the addition of a solution of ammonium persulfate [7727-54-0] N2HgS20g. As the polymerization proceeds, the temperature rises to about 90°C, and then begins to fall at the end of the polymerization. The molecular weight obtained depends primarily on the initiator concentration employed. 

Induction heating is used to heat steel reactor vessels in the chemical process industry (5). The heat produced in the walls is conducted to the material within. Multisectioned cods are used to provide controlled heat input to the process material as it passes through the reactor. Figure 6 illustrates a cross section of such a typical installation. 

K. G. Webley, "Induction Heating of Steel Reactor Vessels," Chemical Process Industry Symposium, AlCHE, Philadelphia, Pa., June 5—8,1978. 

For the production of tartar emetic (antimony potassium tartrate [28300-74-5]), potassium bitartrate [868-14 ] and antimony oxide, Sb202, are added simultaneously to water in a stainless-steel reactor. The reaction mixture is diluted, filtered, and collected in jacketed granulators where crystallization takes place after cooling. Centrihiging, washing, and drying complete the process. 

The fifth component is the stmcture, a material selected for weak absorption for neutrons, and having adequate strength and resistance to corrosion. In thermal reactors, uranium oxide pellets are held and supported by metal tubes, called the cladding. The cladding is composed of zirconium, in the form of an alloy called Zircaloy. Some early reactors used aluminum fast reactors use stainless steel. Additional hardware is required to hold the bundles of fuel rods within a fuel assembly and to support the assembhes that are inserted and removed from the reactor core. Stainless steel is commonly used for such hardware. If the reactor is operated at high temperature and pressure, a thick-walled steel reactor vessel is needed. 

For fixed-bed reactors containing rapidly deactivating catalysts, the scheduled changes ia operating variables to accommodate activity loss can have a marked effect on mn length. This is exemplified by acetylene hydrochiorination to produce vinyl chloride ia tubular fixed-bed reactors. Steel reactors,... 

Traditionally, sodium dichromate dihydrate is mixed with 66° Bh (specific gravity = 1.84) sulfuric acid in a heavy-walled cast-iron or steel reactor. The mixture is heated externally, and the reactor is provided with a sweep agitator. Water is driven off and the hydrous bisulfate melts at about 160°C. As the temperature is slowly increased, the molten bisulfate provides an excellent heat-transfer medium for melting the chromic acid at 197°C without appreciable decomposition. As soon as the chromic acid melts, the agitator is stopped and the mixture separates into a heavy layer of molten chromic acid and a light layer of molten bisulfate. The chromic acid is tapped and flaked on water cooled roUs to produce the customary commercial form. The bisulfate contains dissolved CrO and soluble and insoluble chromic sulfates. Environmental considerations dictate purification and return of the bisulfate to the treating operation. 

An example of what can happen in a production situation is provided in Fig. 1. This photo shows the devastation resulting from a phenol-formaldehyde reactor explosion that occurred at the Borden Chemical plant in Demopolis, Alabama on June 28, 1974. In this explosion, the stainless steel reactor was blown to bits. The reactor operators control room was obliterated. Two people were killed and several others were injured. All nearby property was demolished and windows were broken in homes for a distance of five miles from the plant. 

Many applications of novolacs are found in the electronics industry. Examples include microchip module packaging, circuit board adhesives, and photoresists for microchip etching. These applications are very sensitive to trace metal contamination. Therefore the applicable novolacs have stringent metal-content specifications, often in the low ppb range. Low level restrictions may also be applied to free phenol, acid, moisture, and other monomers. There is often a strong interaction between the monomers and catalysts chosen and attainment of low metals levels. These requirements, in combination with the high temperature requirements mentioned above, often dictate special materials be used for reactor vessel construction. Whereas many resoles can be processed in mild steel reactors, novolacs require special alloys (e.g. Inconel ), titanium, or glass for contact surfaces. These materials are very expensive and most have associated maintenance problems as well. 

Unfortunately, the water contained nitrates, which caused stress corrosion cracking of the mild steel reactor. The reactor was removed for repair, and the temporary pipe that replaced it later failed and caused the explosion (see Section 2.4). 

The reaction was carried out in a passivated Teflon-stainless steel reactor at 150°C for 1 hour, and the yield was >40%. Fluorine pressures of more than 1 atm were generated in this way. 

Chloroaluminate laboratory preparations proved to be easily extrapolated to large scale. These chloroaluminate salts are corrosive liquids in the presence of protons. When exposed to moisture, they produce hydrochloric acid, similarly to aluminium chloride. However, this can be avoided by the addition of some proton scavenger such as alkylaluminium derivatives. In Difasol technology, for example, carbon-steel reactors can be used with no corrosion problem. 

Explosive Properties. It undergoes an expl reaction with H2, but concn and temp limits of the expin were not reproducible in Pyrex or stainless steel reactors, probably due to the presence or absence of Initiating radicals on the walls. The results became more reproducible after the walls were coated with silicone oil. Addn of tetrafluorohydrazine to H2/difluoramine or H2/N trifluoride mixts caused immediate explns (Ref 9). It also can expld on contact with reducing agents or from high press produced by shock wave or blast (Ref 11)... 

To a stainless steel reactor equipped with a heating mantle, a charging port, a condenser for removing ethylene glycol, an inert gas inlet, and a sampling valve were added 400 g of bis(2-hydroxyethyl)terephthalate, 136 g of ethylene glycol, and 0.035 g (or 0.225 g) of sodium acetate trihydrate. The temperature was raised to between 190 and 200°C in 1 h and then 454 g of waste polyester... 

In a typical reactor, 180 g of chipped carpet extrudate was charged to a 43 x 1 -in.-diameter stainless steel reactor while the reactor was purged with nitrogen. Analysis of the extrudate indicated a 57.6% nylon content. The system was sealed... 

The polymerizations were conducted in a 20-liter stainless steel reactor with a pitched-blade turbine agitator and four side-wall baffles. The monomer was polymerized at the same temperature, initiator and monomer concentration in two different inert diluents. The data (Figure 6) illustrate the substantial lowering of the overall heat transfer coefficient for the system with the more highly swollen particles. 

Photocatalytic oxidation tests were performed in a photoreactor [2]. The flat, rectangular stainless steel reactor has dimensions of 578 mm x 113 mm and inlet/outlet ports at the two ends. The aerogel catalyst placed in a recess located at the center of the reactor was uniformly irradiated by... 

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... 

Platelet/housing material Silver/stainless steel Reactor cube dimensions 10 mm X 10 mm x 10 mm... 

GP 7] [R 8] In a later study, a yield of about 40% is found for the same steel reactor [55]. For a ceramic reactor, an even higher yield of 45% is reported. This is explained by a reduction in blank activity (Figure 3.40) (see the sections Activity of... 

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