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Heat-Input Surge

A second event that could result in over-pressuring the column would be a sudden increase in heat input This could be cause by an operator mistakenly putting the temperature controller on manual and opening the steam valve. [Pg.395]


Figure 9.5a shows another control system that can increase heat input to the reboiler if the bottom pump fails. Pump failure will interrupt column vapor flow, the column will dump, and the temperature controller will increase the furnace fuel. Unless a reliable trip system (discussed below) is installed, the furnace will overheat. In one incident (239), resumption of circulation caused rapid vaporization, which resulted in a pressure surge that dislodged... [Pg.248]

The reboiler may also experience inverse response, often referred to as reboiler surge or reboiler swell. An increase in heat input may increase the volume of vapor in the reboiler or the pressure drop in the reboiler and its outlet piping. This will temporarily back up liquid into the column bottom, causing liquid level to rise. [Pg.505]

Equation (12.19) may be implemented for control of product quality by manipulating either heat input or feed rate in relation to the other. The choice depends on the relative availability of each. If short-term reductions in steam availability are common, feed rate should be manipulated accordingly. But if feed is coming from another processing unit without intermediate surge capacity, the alternate arrangement is favored. [Pg.334]

TWINKLE is a multidimensional spatial neutron kinetics code, whieh is patterned after steady-state codes currently used for reactor core design. The code uses an implicit finite-difference method to solve the two-group transient neutron diffusion equations in one, two, and three dimensions. The code uses six delayed neutron groups and contains a detailed multi-region fuel-clad-coolant heat transfer model for calculating point-wise Doppler and moderator feedback effects. The code handles up to 2000 spatial points and performs its own steady-state initialisation. Aside from basic cross-section data and thermal-hydraulic parameters, the code accepts as input basic driving functions, such as inlet temperature, pressure, flow, boron concentration, control rod motion, and others. Various edits are provided (for example, channel-wise power, axial offset, enthalpy, volumetric surge, point-wise power, and fuel temperatures). [Pg.122]

Flash Units. In simulators, the term flash refers to the module that performs a single-stage vapor-liquid equilibrium calculation. Material, energy, and phase equilibrium equations are solved for a variety of input parameter specifications. In order to specify completely the condition of the two output streams (liquid and vapor), two parameters must be input. Many combinations are possible—for exanple, temperature and pressure, temperature and heat load, or pressure and mole ratio of vapor to liquid in exit streams. Often, the flash module is a combination of two pieces of physical equipment, that is, a phase separator and a heat exchanger. These should appear as separate equipment on the PFD. Note that a flash unit can also be specified for batch operation, in which case the unit can serve as a surge or storage vessel. [Pg.417]

Hydrodesulfurization (HDS) is a continuous plant used to produce Naphtha and Diesel from H2 and raw diesel using heating and reaction chemical processes. Figure 9-1 shows the block diagram of the HDS process, which is composed of 4 main blocks Feed Surge-Drum, Reactor, Scrubber, and Stripper, while the input is Diesel and H2 and the output is Naphtha, Diesel, and Gass-off. [Pg.137]


See other pages where Heat-Input Surge is mentioned: [Pg.395]    [Pg.395]    [Pg.133]    [Pg.236]    [Pg.127]    [Pg.194]    [Pg.249]    [Pg.464]   
See also in sourсe #XX -- [ Pg.395 ]




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Heat input

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