Feedstock variations

The feedstock variation will impact on the characteristics of the raw-gas. Added to the effect of the feedstock variation is the cyclic impact of loading of lockhoppers, full of fresh feedstock, into the reactor. Thus, the downstream purification system can be expected to be faced with a wide and constantly changing range of concentrations of minor species. 

In a more perfect world, fuel properties would be the same from all producers everywhere. Unfortunately, this is not the case, and fuel properties vary according to production plant, feedstock variations and quality, production quality control, and the presence of contaminants picked up during storage and distribution. 

Feed composition variation. One way of allowing for design uncertainties and feedstock variation is by installing alternate feed points. In packed towers, every alternate feed point requires expensive distribution equipment. 

Similarly, after blending about 30vol.% of propylene with cis-2-butene, the RON loss was less than 1 number. With H2SO4 alkylation, similar amounts of propylene would lead to a RON about 1.5 lower. Table 12.10 summarizes the estimated impact of feedstock variation on RON relative to a pure cis-2-butene feedstock for the AlkyClean process and liquid acid technologies. Based on these results, it can be concluded that our new SAC technology is less sensitive to feedstock variation regarding product quality than either liquid acid technology. 

AlkyClean process are fully competitive tvith current liquid acid technologies. High quality product has been produced in an operation that has proven to be reliable and robust. Sensitivity to feedstock variation is lotv and tolerance to impurities is high. The economic competitiveness of the netv SAC process is enhanced by its low mechanical complexity and the use of common (i.e., non-proprietary) refinery process equipment. 

Enhanced feedstock variations (contaminated scrap, low-grade scrap)... 

A Hquid-phase variation of the direct hydration was developed by Tokuyama Soda (78). The disadvantages of the gas-phase processes are largely avoided by employing a weakly acidic aqueous catalyst solution of a siHcotungstate (82). Preheated propylene, water, and recycled aqueous catalyst solution are pressurized and fed into a reaction chamber where they react in the Hquid state at 270°C and 20.3 MPa (200 atm) and form aqueous isopropyl alcohol. Propylene conversions of 60—70% per pass are obtained, and selectivity to isopropyl alcohol is 98—99 mol % of converted propylene. The catalyst is recycled and requites Htde replenishment compared to other processes. Corrosion and environmental problems are also minimized because the catalyst is a weak acid and because the system is completely closed. On account of the low gas recycle ratio, regular commercial propylene of 95% purity can be used as feedstock. 

Deep C t lytic Crocking. This process is a variation of fluid catalytic cracking. It uses heavy petroleum fractions, such as heavy vacuum gas oil, to produce propylene- and butylene-rich gaseous products and an aromatic-rich Hquid product. The Hquid product contains predorninantiy ben2ene, toluene, and xylene (see BTX processing). This process is being developed by SINOPEC in China (42,73). SINOPEC is currentiy converting one of its fluid catalytic units into a demonstration unit with a capacity of 60,000 t/yr of vacuum gas oil feedstock. 

Products from the distiUation of complex mixtures are in themselves complex mixtures. The character and yields of these produces vary widely, depending upon the source of the feedstock. Even crude oUs from the same locality may exhibit marked variations. 

Mean bed particle size (thus, the in-bed heat-transfer coefficient) may vary for external reasons such as a change of feedstock supply or a deterioration in crusher performance. This potential source of variation should be considered before any decision to resurface is made. 

Nonuniform Feedstock should be blended before milling feedstock causes, feej t-ock before commencing milling opera- variation in oper- moisture content) ating conditions resulting in overheating. CCPS G-1 CCPS G-23 CCPS G-29... 

As one would expect, in those cases in which the ionic liquid acts as a co-catalyst, the nature of the ionic liquid becomes very important for the reactivity of the transition metal complex. The opportunity to optimize the ionic medium used, by variation of the halide salt, the Lewis acid, and the ratio of the two components forming the ionic liquid, opens up enormous potential for optimization. However, the choice of these parameters may be restricted by some possible incompatibilities with the feedstock used. Undesired side reactions caused by the Lewis acidity of the ionic liquid or by strong interaction between the Lewis acidic ionic liquid and, for example, some oxygen functionalities in the substrate have to be considered. 

These applications avoid the major obstacles for using biomass for electricity generation fluctuation in the supply, and the type of biomass available. Seasonal variations and differing quality of feedstock are the biggest barriers to more widespread use. This is especially true for biomass wastes. 

Figures 35.39 and 35.40 show a tremendous dependency on both power-law parameters. The pressure buildup and nip force very much depend on the viscous behavior of the rubber compound. Although not calculated one can simply understand that a varying feedstock temperature will cause variations in the nip force because the viscosity of rubber compounds very much depends on temperature.

Variations in feedstock quality Highly variable product quality, 3.1... 

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