Secondary heater

Hot plates are also used to heat one type of material so that a second may be heated. These secondary heaters may include water baths, oil baths, sand traps, or aluminum plates. Water and oil baths are typically used to heat a drying flask on vacuum evaporators. Oil baths are more messy and require special clean up, but the oil (typically a silicone oil) will not evaporate during drying processes that can take up to several hours. Stronski came up with a very simple and easy solution to limit water evaporation. Stronski8 recommended that the user float Styrofoam popcorn or chips up to three inches deep on water. This suggestion not only limited evaporation, but extended the maximum controlled temperature range. 

Fuel-Staged Burners Use of fuel-staged burners is the preferred combustion approach for NO control because gaseous fuels typically contain little or no fixed nitrogen. Figure 27-36 illustrates a fuel-staged natural draft refineiy process heater burner. The fuel is spht into primaiy (30 to 40 percent) and secondary (60 to 70 percent) streams. Furnace gas may be internally recirciJated by the primaiy... 

The soluble copper ammonia ion passes through the condensate system and plates out as a cathode on steel surfaces in the deaerator, heaters, economizer, and the boiler itself. A secondary galvanic corrosion process is initiated that damages the surrounding steel by forming ferrous hydroxide and releasing copper and ammonia. The ammonia carries over into the steam, and the entire corrosion process repeats itself. 

Accident statistics on the equipment involved in large losses give somewhat contradictory information (see Table 20). According to Mahoney (1992) the most common process items as primary accident cause are reactors. The next in the list are process drums whereas heaters are one of the safest. This contrasts with Instone s (1989) data, where heaters and boilers were the most common process items in the accidents, whereas reactors and process drums were quite uncommonly involved. This difference may be partly because Mahoney has analyzed the primary causes of large losses, whereas Instone has listed the involvement of equipment in losses. Since furnaces are sources of ignition for flammable leaks from other equipment, furnaces are not necessarily listed as primary causes even they are probably involved as secondary causes in many losses. Therefore the inclusion of both reactors and furnaces in the list of most unsafe equipment is well justified. 

Leak repair, fired heater, 10 162 Leaks and spills, secondary containment of, 24 311. See also Spills and leaks Leaky Lamb waves, propagating,... 

Many oil burners are designed as combination gas/oil burners. An example of a modern low-NO oiFgas forced-draftl)urner is shown in Fig. 24-28. This is an air-staged design, with the air divided into primary, secondary, and tertiary streams. An air-staged natural draft process heater oil/gas burner is illustrated in Fig. 24-29. 

Pulverized coal is fed directly from a variable speed auger into the high velocity primary air stream which conveys it to the injector at the top of the furnace. The coal and primary air enter the combustor through a single low-velocity axial jet. Secondary combustion air is divided into two flows which enter the combustor coaxial to the primary stream. Part of the flow is introduced through a number of tangential ports to induce swirl which is necessary for flame stabilization. The remainder enters the combustor axially. The two secondary air streams are separately preheated using electrical resistance heaters. 

Did the oxygen analyzer really help us find the point of absolute combustion for the forced-draft boiler No, it did not. However, once you have found the point of absolute combustion and then noted the corresponding flue-gas percent 02, as long as all operating conditions remain constant for the heater (and in reality the longest time you could hope that all conditions would truly be constant would be /2 h), then you could use the percent 02 in the flue gas as a rather secondary... 

If you try to operate a furnace, fired heater, or boiler with too little combustion air to starve the burners of oxygen to smother or bog down the firebox, then you will likely cause afterburn or secondary combustion in the stack, you will not be able to operate on automatic temperature control, and may even destroy the equipment altogether. 

Primary expls (initiating) are used to start the train of reactions which results in the deton of secondary HE s or of the functioning of ammo. These expls are the most sensitive of all chemical components in military ammo, hence, the most hazardous. Primary expls can be ignited by an elec heater or spark, heat from mechanical friction, a free flame, or by an RF (radio frequency) signal. The ideal primary expl is a single compd, since this affords greatest control of its characteristics. Unfortunately, such a compd is not always available so that mixts must usually be used... 

Naphtha that is either naturally sweet (no odor) or has been treated until sweet is subdivided into several fractions in efficient fractional distillation towers, frequency called column steam stills. A typical arrangement consists of primary and secondary fractional distillation towers and a stripper. Heavy naphtha, for example, is heated by a steam heater and passed into the primary tower, which is usually operated under vacuum. The vacuum permits vaporization of the naphtha at the temperatures obtainable from the steam heater. 

The first alternative simplifies the heat integration of the chemical process, and the second simplifies the interface between the chemical process and the secondary loop. CEA (Leybros, 2009) has designed their S-I process for the first alternative, as the requirements for the reactor expected to be used are most suitable for it. GA has developed flow sheets for both alternatives. Sandia National Laboratories (SNL) is a partner of both CEA and GA in the operation of a demonstration loop for the S-I cycle. SNL is charged with design and operation of the sulphuric acid decomposition section. They have developed a bayonet-heater design for the decomposer which incorporates internal heat recovery. As a result, the outlet temperature of the bayonet heat modules is too low to use in the HI decomposition section. Thus, helium is utilised in the HI decomposition section, as in the CEA flow sheets. 

Due to the difference of pressures in the appratuses raw trichlorfon continuously flows out of the ager into the system where secondary unreacted products are distilled. First, raw trichlorfon is heated to 80 °C in heater 5 by sending hot water into the space between the pipes. Then, the mixture leaves the heater and enters distillation tower 6, filled with Raschig rings and fashioned with a coil with hot water. Distillation is conducted at 80-90°C and a residual pressure of 26-27 GPa. The distilled unreacted products (mostly chloral) flow through cooler 7 into collector 8 and are loaded into the distillation tank as they accumulate. There chloral is distilled over sulfuric acid, and the ready product, trichlorfon, continuously flows from tower 6 into collector 9. It is heated with 40 °C water (through the jacket). 

Through the use of such utilization function costs, the turbine costs are separated into primary turbine costs, which by definition are insensitive to the temperature and pressure of the steam, and secondary turbine costs which are automatically paid for by neighboring components via requiring their purchase of utilization functions. The primary turbine cost formulae then result in equal units costs Xg of the bleed steam essergy for all of the feedwater heaters. Thus Xg is then constant with respect to temperature, thereby meeting the condition of thermo-economic isolation of the feedwater heaters with respect to the turbines. 

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