Leaners

Gas is produced to surface separators which are used to extract the heavier ends of the mixture (typically the components). The dry gas is then compressed and reinjected into the reservoir to maintain the pressure above the dew point. As the recycling progresses the reservoir composition becomes leaner (less heavy components), until eventually it is not economic to separate and compress the dry gas, at which point the reservoir pressure is blown down as for a wet gas reservoir. The sales profile for a recycling scheme consists of early sales of condensate liquids and delayed sale of gas. An alternative method of keeping the reservoir above the dew point but avoiding the deferred gas sales is by water injection. 

In general, it has been found that much visible smoke is formed in small, local fuel-rich regions. The general approach to eliminating smoke is to develop leaner primary zones with an equivalence ratio between 0.9 and 1.5. Another supplementary way to eliminate smoke is to supply relatively small quantities of air to those exact, local, over-rich zones. 

As can be seen from Fig, 3.7, the pinch decomposes the synthesis problem into two regions a rich end and a lean end. The rich end comprises all streams or parts of streams richer than the pinch composition. Similarly, the lean end includes all the streams or parts of streams leaner than the pinch composition. Above the pinch, exchange between the rich and the lean process streams takes place. External MSAs are not required. Using an external MSA above the pinch will incur a penalty of eliminating an equivalent amount of process lean streams from service. On the other hand, below the pinch, both the process and the external lean streams should be used. Furthermore, Fig. 3.7 indicates that if any mass is transferred across the pinch, the composite lean stream will move upward and, consequently, external MSAs in excess of the minimum requirement will be used. Therefore, to minimize the cost of external MSAs, mass should not be transferred across the pinch. It is worth pointing out that these observations are valid only for the class of MEN problems covered in this chapter. When the assumptions employed in this chapter are relaxed, more general conclusions can be made. For instance, it will be shown later that the pinch analysis can still be undertaken even when there are no process MSAs in the plant. The pinch characteristics will be generalized in Chapters Five and Six. 

As the liquid falls, it becomes leaner and leaner in light ends, and richer and richer in heavy ends. At the bottom of the tower some of the liquid is circulated through a reboiler to add heat to the tower. As the gas goes up from tray to tray, more and more of the heavy ends get stripped out of the gas at each tray and the gas becomes richer and richer in the light... 

The contactor works in the same manner as a condensate stabilizer tower described in Chapter 6. As the glycol falls from tray to tray it becomes richer and richer in water. As the gas rises it becomes leaner and leaner in water vapor. Glycol contactors will typically have between 6 and 12 trays, depending upon the water dew point required. To obtain a 7 Ib/MMscf specification, 6 to 8 trays are common. 

The de-methanizer is analogous to a cold feed condensate stabilizer As the liquid falls and is heated, the methane is boiled off and the liquid becomes leaner and leaner in methane. Heat is added to the bottom of the tower using the hot discharge residue gas from the compressors to assure that the bottom liquids have an acceptable RVP or methane content. 

After filling the receiver, reflux runs down the column at the same molar rate as the vapor back up (L = G). The operating line has a slope of 1.0. Then there are n plates/trays between composition Xp and xj (the mol fraction in distillate). As the distillation continues, the operating line moves closer to the 45° line of the diagram, and x and Xp (and Xj) become richer and leaner, respectively, until at the end xj becomes Xq and x becomes x. The required time is 02. 

In contrast to the lean propane flame, the burning intensity of the lean limit methane flame increases for the leading point. Preferential diffusion supplies the tip of this flame with an additional amoxmt of the deficient methane. Combustion of leaner mixture leads to some extension of the flammability limits. This is accompanied by reduced laminar burning velocity, increased flame surface area (compare surface of limit methane... 

Reactant Excessively mixture leaner or richer mixture... 

Similarly, Figure 6.3.9b depicts the situation in which partial quenching of the flame results from unequal composition of the reactant mixtures issued from the inner and outer tubes, while keeping the mean velocities constant. If the equivalence ratio in the inner tube is excessively leaner or richer to exceed a typically flammable range, it would result in local extinction, thereby exhibiting a hole in the center of the premixed flame. 

With the passage of time, the average grade of the ores mined for metal production has become progressively leaner, and this trend will continue in the future because metallic... 

I had last seen Ned at Ludlow, some months since. I did not take Dickon with me as I had planned, for he was sick, but I was sorry for it. Ned knelt to me and I raised him, and found him well grown for his eight years, his hair still pale gold and his face a little leaner and more tanned from his knightly exercises in these long, warm days. He was proud to show me his skill at the... 

Ingestion of venison taken in hunting activity is assumed to be 11 kg by each member of a family of four per year. The value of Kpa is adjusted by a factor of 2/3, because venison is a leaner meat, perhaps 20% fat, than beef. The animals browse over a wide area, including uncontaminated land, for which reason a factor of 0.1 is introduced. The equation thus derived (with BW = 70) is... 

Over the last 40 years conventional poultry (and in particular chicken) production has undergone the most extreme level of intensification of all major livestock production systems. This was driven by a more rapid increase in demand for poultry meat (which was perceived by consumers as leaner and healthier) and to a lesser extent eggs, compared to other livestock products (e.g. red meat, milk), which often saw unchanged or decreasing consumption patterns (Frazer, 1996 Tilman et al., 2002). 

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