Nominal steam rates

Recommended nominal steam rates at 60 m/s exit velocity for a typical flare tip are shown in Figure 2. At lower velocities, higher steam ratios are required. Typical steam control consists of a flow ratio controller with adjustable ratio set point, related to flare gas flow. The ratio adjustment, located in the control house, provides for the higher steam ratios necessary at low flaring rates. 

CEI produced the Sulphlex-233/ in 7.5 ton (6.8 tonne) batches the reaction vessel has a nominal 9 ton (8.2 tonne) capacity, is steam heated, and is equipped with a wet scrubber system to control potential hydrogen sulfide emissions. Since no cooling capability was available, the reaction exotherm was controlled by the rate at which the preblended chemical modifiers were added to the reaction mass. 

Find the flow coefficient K from the same ASME source by entering the 10-in nominal pipe diameter table al ft = 0.5999 and projecting to the appropriate Reynolds number column. Assume that the Reynolds number = 107, approximately, for the flow conditions in this pipe. Then, K = 0.6486. Since the Reynolds number for steam pressures above 100 lb/in2 ranges from 106 to 107, this assumption is safe because the value of K does not vary appreciably in this Reynolds number range. Also, the Reynolds number cannot be computed yet because the flow rate is unknown. Therefore, assumption of the Reynolds number is necessary. The assumption will be checked later. 

After heating by steam condensation, the nominal (maximum possible) acid strength of 4.036 % by weight corresponds to a hydrogen ion concentration of 0,417 mole/liter. Thus, according to chapter 5, with T = (273.16 +153) °K = 426.16 °K, the maximum possible rate constant of pentose disappearance is found to be ki = 0.02357 min" ... 

On this basis, the selection of a group of steam traps to handle all steam tracing situations is possible. Actually this consists of a 3/8-inch nominal size trap but many steam trap manufacturers rate their traps by orifice size rather than by connection size. Suitable traps should have 150 psig steam condensate capacities from 350 to 600 pounds per hour at saturation temperature, and from 550 to 850 pounds per hour at 30°F below saturation temperature. Using 15 psig steam, the condensate capacity should range between 135 and 250 pounds per hour at saturation temperature and from 225 to 400 pounds per hour at 30°F below saturation temperature. 

Rotary (indirect convection) temperature 300 °C area 10-1000 m evaporative capacity 9 g water evaporated/s m or 0.5-4 g water/s m of peripheral area 5 to 10% solids, residence time 0.1 V/volumetric feed rate gas velocity 1-1.5 m/s peripheral velocity 0.1-0.5 m/s. Steam heated gas temp 120-175 °C size on volumetric heat transfer coefficient power 0.15-0.25 kW/m nominal circumferential area. L/D = 5.5/1. Assume average temperature of evaporation throughout is 3°C above inlet wet-bulb temperature. Peripheral area/volume = 1.4-2.6 or about 2 m peripheral area/m dryer volume. Indirect rotary 0.5-4 g water evap/s m. ... 

Another way of reducing the specific mass of lead bismuth coolant is to increase its average flow rate and to diminish the length of circulation circuit. However, this approach has its own constraints caused by the necessity to meet safety requirements. The first requirement is defined by the necessity to provide the power level of the reactor with naturally circulating lead bismuth coolant at the level not less than 5...7% of its nominal power. This makes it possible to eliminate inadmissible temperature increase under a shutdown of main circulation pumps. The second requirement is conditioned by the necessity to secure conditions for the assured surfacing of steam bubbles from lead bismuth coolant to its free surface level under the rupture of steam generator (SG) tubes. This is important to eliminate steam ingress into the core and inadmissible pressure increase in the mono-block vessel. 

Primary coolant flow rate Reactor operating pressure Coolant inlet temperature, at core inlet Coolant outlet temperature, at riser outlet Mean temperature rise across core Primary circuit volume, including pressurizer Number of coolant loops Steam flow rate at nominal conditions Feedwater flow rate at nominal conditions Steam temperature/pressure Feedwater temperature... 

For this reason, under of the nominal load, the reactor is operated by reducing the coolant density. This is obtained by recirculating a portion of the steam to the core inlet through a steam blower. The steam flow rate is then established so as to ensure a stable coolant flow in the power channels. 

At the next step, water was purged from SHS channels. The transioit processes took place in the second loop, while constant pressure and boiling-free cooling of BWs were provided in the primary loop. Reactor power was rqjidly reduced to 2% of its nominal level and feedwater flow rate was reduced to provide water level in the SGs to purge SHS channels. The water—steam mixture from evaporators and steam from the steam loop were directed to the bubbler and then to the deaerator and the turbine condenser. 

Open a new case in Hysys. Add water as the pure component, and select ASME steam for the fluid package. Construct the pipe process flow sheet and specify the feed stream conditions. Double click on Pipe Segment on the process flow sheet, click on the Rating tab, and then click on Append Segment to add the pipe specification (length, nominal size, elevation, and fittings) as shown in Figures 2.58 and 2.59. 

At the entrance and exit of the coil reactor, the temperatures are 326.5°C and 439 C, and the pressure is 2.62 and 0.90MPa (1.72MPa of delta-P), respectively. A typical feed flowrate of 124,300kg/h (about 20,000 barrel per day of nominal feed flowrate) is assumed for simulation purposes. One weight percentage of water steam was also fed to the coil reactor. Delta-P and steam flowrate are typical values reported in the literature (Joshi et al., 2008). Since the coil reactor is modeled as non-isothermal reactor, the required heat transfer rate is 4.33 x lO kJ/h. For the case of the soaker reactor, it is modeled as adiabatic reactor, so that temperature will reduce due to the endothermic nature of the visbreaking reactions. 

Stable reflux condensation with liquid flowing counter-current to steam in the hot legs flow-rate is sufficient to remove core power till loop mass inventory achieves values as low as 30-40% of the nominal values ... 

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