Side stream injection

The flow rate of a hot coal/oil slurry in a pipeline is measured by injecting a small side stream of cool oil and measuring the resulting temperature change downstream in the pipeline. The slurry is initially at 300°F and has a density of 1.2 g/cm3 and a specific heat of 0.7 Btu/(lbm °F). With no side stream injected, the temperature downstream of the mixing point is 298°F. With a side stream at 60°F and a flow rate of 1 lbm/s, the temperature at this point is 295°F. The side stream has a density of 0.8 g/cm3 and a cp of 0.6 Btu/(lbm °F). What is the mass flow rate of the slurry ... 

Symmetric Mode with Side Stream Injection... 

Figure 6.16 displays the temperature profile and liquid-phase molar fractions for cumene and DIPB. It may be observed that the temperature is practically constant over the reactive sections with a first plateau at 200 °C and a second one at 210 °C. The top temperature is at 198 °C while the bottom temperature climbs to 242 °C. The explanation may be found in the variation of concentrations for cumene and DIPB in the liquid phase. The maximum reaction rate takes place on the stages where propylene is injected. The cumene concentration increases rapidly and reaches a flat trend corresponding to the exhaustion of the propylene in liquid phase. It may be seen that the amount of DIPB increases considerably in the second reaction zone. This variation is very different from that with a cocurrent PFR. The above variations suggest that the productivity could be improved by providing several side-stream injections and/or optimizing the distribution of catalyst activity. 

The simplest unit employing vacuum fractionation is that designed by Canadian Badger for Dominion Tar and Chemical Company (now Rttgers VFT Inc.) at Hamilton, Ontario (13). In this plant, the tar is dehydrated in the usual manner by heat exchange and injection into a dehydrator. The dry tar is then heated under pressure in an oil-fired hehcal-tube heater and injected directly into the vacuum fractionating column from which a benzole fraction, overhead fraction, various oil fractions as side streams, and a pitch base product are taken. Some alterations were made to the plant in 1991, which allows some pitch properties to be controlled because pitch is the only product the distillate oils are used as fuel. 

In order to minimize operating costs of the process, nitric acid is recovered within the catholyte. A side stream is heated to boiling and refluxed into a packed column, into which air or 02 is injected. 

If AW AW the process of finding a linear-mixture basis can be tedious. Fortunately, however, in practical applications Nm is usually not greater than 2 or 3, and thus it is rarely necessary to search for more than one or two combinations of linearly independent columns for each reference vector. In the rare cases where A m > 3, the linear mixtures are often easy to identify. For example, in a tubular reactor with multiple side-injection streams, the side streams might all have the same inlet concentrations so that c(2) = = c(iVin). The stationary flow calculation would then require only AW = 1 mixture-fraction components to describe mixing between inlet 1 and the Nm — I side streams. In summary, as illustrated in Fig. 5.7, a turbulent reacting flow for which a linear-mixture basis exists can be completely described in terms of a transformed composition vector ipm( defined by... 

A similar volume defined injection protocol where the sample is confined within two controlled side streams of buffer solution has been developed by the group of Ramsey and has been dubbed pinched injection scheme [31]. The... 

In the vacuum tower, heavy liquids from the atmospheric tower, referred to as reduced crude, are fed to a vacuum furnace and heated to about 750—800 °F. To suppress coking in the furnace tubes, steam is added to increase the velocity of the hydrocarbon in the tubes. The reduced crude enters the vacuum tower flash zone, where the pressure is maintained at 20—30 mmHg absolute (2600-4000 Pa). When foaming occurs, fouling of the demister pads (sets of grids designed to minimize entrainment of heavier liquids into the upper sections of the tower) above the flash zone can occur, side stream gas oil products will be discolored, and gas oil end-point specification cannot be met. Again, silicone additives are used. The antifoam is normally injected into the feed to the... 

Turk and coworkers in their laboratory and full-scale tests used activated carbon in conjunction with the continuous injection of a small side stream of ammonia gas [48], They found that such set-up is able to enhance the capacity for MM removal by a factor 3-8. Once again, this process resulted in providing basic enviroranent. 

Similar to methanamide, ammonium formate decomposition proceeded in a wide temperature window. As ammonium formate does in fact not need to be hydrolyzed, formic acid decomposition is the limiting reaction for the quantitative conversion of the precursor solution to NH3 and CO2. However, if mixtures with urea, such as Denoxium are being used, the temperature needs to be sufficient to enable urea hydrolysis. Therefore, an in-pipe or side stream system equipped with an Au/Ti02 hydrolysis catalyst could in fact be used to provide NH3 from either AdBlue , Denoxium or Admide(R). This would enable the flexibility to ensure efficient NH3 production, and, consequently, NO reduction, even in cold climates or during long refill intervals. Guanidinium formate solution would also be an optional NH3 precursor solution for a side stream reactor if the reactor could be electrically heated at temperatures below 250 °C, but would not qualify for direct injection into the main exhaust pipe. 

Lube distillates are sent at their bubble points to side stream strippers. Steam is injected, reducing the partial pressure of hydrocarbons which effectively removes lighter hydrocarbons improving volatility beyond that obtainable without side stripping. Ten to thirty percent of the stream may be removed in the stripper. If the heavier streams are not stripped this will reduce the yield of lighter lubes. Stripping is an important part of the overall operation to achieve the best separation and produce the desired products. A stripper typically consists of 4 to 6 sieve trays but packing may also be used. 

The size of the leakage was determined as follows. Radiation detectors were mounted on the inlet of the first side, and the outlet of the second side of the heat exchanger and at additional locations for control. A short pulse of Kr-85 tracer (<0.1 sec) was injected into the feed stream, which gave rise to detector responses shown in figure 3. 

Two different types of dynamic test have been devised to exploit this possibility. The first and more easily interpretable, used by Gibilaro et al [62] and by Dogu and Smith [63], employs a cell geometrically similar to the Wicke-Kallenbach apparatus, with a flow of carrier gas past each face of the porous septum. A sharp pulse of tracer is injected into the carrier stream on one side, and the response of the gas stream composition on the other side is then monitored as a function of time. Interpretation is based on the first two moments of the measured response curve, and Gibilaro et al refer explicitly to a model of the medium with a blmodal pore... 

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