Heating of vessels

Cp specific heat at constant pressure, J/(kg °C) Cv specific heat at constant volume, J / (kg °C) Cves specific heat of vessel, kJ/°C... 

Electrical heating and refrigeration loads, trace heating of vessels and piping. 

The highest performance and best safety features are the qualities of an advanced microwave extraction system in the industry. It offers fast heating of vessel together with homogeneous microwave distribution throughout the cavity. 

The heating of the vessels is accomplished by means of a small bath or a micro-Bunsen burner. The vessel can be clamped at such a distance from the burner that the contained liquid boils gently under reflux. Smooth boiling is ensured by the addition of 1-2 minute pieces of unglazed porcelain, or of a short piece of melting-point tubing open at both ends. 

Shipment, Stora.ge, ndPrice. Butyrolactone is shipped in unlined steel tank cars and plain steel dmms. Plain steel, stainless steel, aluminum, and nickel are suitable for storage and handling mbber, phenoHcs, and epoxy resins are not suitable. Butyrolactone is hygroscopic and should be protected from moisture. Because of its low free2ing point (—44° C), no provision for heating storage vessels is needed. 

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

Because the reaction takes place in the Hquid, the amount of Hquid held in the contacting vessel is important, as are the Hquid physical properties such as viscosity, density, and surface tension. These properties affect gas bubble size and therefore phase boundary area and diffusion properties for rate considerations. Chemically, the oxidation rate is also dependent on the concentration of the anthrahydroquinone, the actual oxygen concentration in the Hquid, and the system temperature (64). The oxidation reaction is also exothermic, releasing the remaining 45% of the heat of formation from the elements. Temperature can be controUed by the various options described under hydrogenation. Added heat release can result from decomposition of hydrogen peroxide or direct reaction of H2O2 and hydroquinone (HQ) at a catalytic site (eq. 19). 

Fresh butane mixed with recycled gas encounters freshly oxidized catalyst at the bottom of the transport-bed reactor and is oxidized to maleic anhydride and CO during its passage up the reactor. Catalyst densities (80 160 kg/m ) in the transport-bed reactor are substantially lower than the catalyst density in a typical fluidized-bed reactor (480 640 kg/m ) (109). The gas flow pattern in the riser is nearly plug flow which avoids the negative effect of backmixing on reaction selectivity. Reduced catalyst is separated from the reaction products by cyclones and is further stripped of products and reactants in a separate stripping vessel. The reduced catalyst is reoxidized in a separate fluidized-bed oxidizer where the exothermic heat of reaction is removed by steam cods. The rate of reoxidation of the VPO catalyst is slower than the rate of oxidation of butane, and consequently residence times are longer in the oxidizer than in the transport-bed reactor. 

Reductive alkylations and aminations requite pressure-rated reaction vessels and hiUy contained and blanketed support equipment. Nitrile hydrogenations are similar in thein requirements. Arylamine hydrogenations have historically required very high pressure vessel materials of constmction. A nominal breakpoint of 8 MPa (- 1200 psi) requites yet heavier wall constmction and correspondingly more expensive hydrogen pressurization. Heat transfer must be adequate, for the heat of reaction in arylamine ring reduction is - 50 kJ/mol (12 kcal/mol) (59). Solvents employed to maintain catalyst activity and improve heat-transfer efficiency reduce effective hydrogen partial pressures and requite fractionation from product and recycle to prove cost-effective. 

PWRs operate differendy from BWRs. In PWRs, no boiling takes place in the primary heat-transfer loop. Instead, only heating of highly pressurized water occurs. In a separate heat-exchanger vessel, heat is transferred from the pressurized water circuit to a secondary water circuit that operates at a lower pressure and therefore enables boiling. Because of thermal transfer limitations, ultimate steam conditions in PWR power plants ate similar to those in BWR plants. For this reason, materials used in nuclear plant steam turbines and piping must be more resistant to erosion and thermal stresses than those used in conventional units. 

Framing. The framed bar process is by far the oldest and the most straightforward process utilized in the production of bar soaps. The wet base soap is pumped into a heated, agitated vessel commonly referred to as a cmtcher. The minor ingredients used in soap bars such as fragrance or preservative are added to the wet soap in the cmtcher or injected in-line after reduction of product stream temperature. The hot mixture is then pumped into molds and allowed to cool. 

The first reactor in series in the Arco, lEP, and Phillips processes is adiabatic (vessel filled with catalyst). The exothermic heat of reaction is removed in a pump-around loop where a portion of the reactor contents are taken from the reactor, pumped through an external exchanger, cooled, and returned to the reactor. 

At temperatures above 50°C, irreversible hydrolysis to formate and ammonia becomes important. If the heat of reaction is not removed, the increased temperature accelerates the decomposition and can create high pressure in a closed vessel. 

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