Liquid yields, increasing

Addition of ZSM-5 in a catalytic cracking unit can permit a reduction in reformer severity. At a given pool octane requirement, the higher FGG octane contribution (Research/Motor) allows for lower reformer severity and, consequently, higher reformate yields. At EniGhem s Gela FGG unit fl2-14). when ZSM-5 was in the FGG, the reformate severity dropped from 95.0 RON clear to 90.0 RON clear while liquid yield increased by 4% vol. 

The ruthenium(111) acetylacetonate-cobalt(II) iodide couple, for example, when dispersed in tetrabutylphosphonium bromide (ex. 1) and treated with 1/1 CO/H2 at 220°C, generates a liquid product containing 76 wt % acetic acid plus 1.1 wt % propionic acid (111 mmol total acid). The liquid yield increase is 66% and the estimated carbon selectivity to acetic plus propionic acids and their esters is 84%. There is normally no metallic residue at this stage, ruthenium and cobalt recovery is essentially quantitative at the end of the run, and the product acids may be recovered in >90% purity by fractional distillation. Methane and water are the major by-products (4). 

Table IV shows the results. When the acidity is preferentially poisoned by equilibrating the catalyst with a feed containing 8 ppm of nitrogen, the following effects are noted (1) Total liquid yield increases by about 1 wt / (2) the jet fuel increases by 6 LV % ...

To address the deactivation behavior in more detail, Uemichi et al. recently examined the change in activity of a silica-alumina catalyst with 13 wt% alumina as a function of time on stream. At a reaction temperature of 723 K, the SA catalyst accumulated over 12 wt% coke on the catalyst after 250 min time on stream. The liquid yield increased slightly from 60 wt"/o to approximately 70 wt% as the coke built up on the catalyst. The limited effect of the coke on the reaction was attributed to the inability of coke deposits to block completely the large pores (f/p,ave = 4.4 nm) of the amorphous catalyst. Although SA showed no activity toward cracking of -octane, the reactivity of polyethylene was substantially enhanced in the presence of the catalyst. This was attributed to the facile reaction on the catalyst of olefins which could be formed from thermal degradation of polyethylene at the temperatures used in this study. 

An early patent by the Ford Motor Company reported the use of basic salts to degrade automobile shredder residue, a mixture containing 12.7 wt% polypropylene. With the addition of 2 g of sodium carbonate powder to 40 g of auto shredder residue, the total liquid yield increased by approximately 3%, and the overall olefin yield increased by approximately 20%. The benefit observed increased with the amount of the sodium salt added. The same effect was observed when calcium and potassium carbonates were used, but magnesium and zinc carbonate actually increased the amount of char formed. 

Ethanol may constitute up to 61 mol % of the alkanol product with ruthenium-titanium alkoxide catalyst combinations (expt. 1), the C1-C3 alkanols may comprise up to 65 wt % of the total product and liquid yield increases exceed 200% (expt. 2). 

Table IX illustrates the generation of N,N-dimethylformamide (DMF) and N-methylformamide (MMF), plus formamide, using different ruthenium catalyst precursors dispersed in tetrabutylphosphonium bromide and iodide. In the first entry, treatment of the Ru3(C0)x2 Bu4PI dispersion with CO/H2/NH3 at 220 C for 4 h yielded a liquid product comprising 24% DMF and 43% MMF. The liquid yield increase was 112%. Entry 2...

As the temperature increased, the gas yield decreased from 40-25% and liquid yield increased from 20-45%. With ZnClj, the gas yield increased and liquid yield decreased. 

From stochastic molecnlar dynamics calcnlations on the same system, in the viscosity regime covered by the experiment, it appears that intra- and intennolecnlar energy flow occur on comparable time scales, which leads to the conclnsion that cyclohexane isomerization in liquid CS2 is an activated process [99]. Classical molecnlar dynamics calcnlations [104] also reprodnce the observed non-monotonic viscosity dependence of ic. Furthennore, they also yield a solvent contribntion to the free energy of activation for tlie isomerization reaction which in liquid CS, increases by abont 0.4 kJ moC when the solvent density is increased from 1.3 to 1.5 g cm T Tims the molecnlar dynamics calcnlations support the conclnsion that the high-pressure limit of this unimolecular reaction is not attained in liquid solntion at ambient pressure. It has to be remembered, though, that the analysis of the measnred isomerization rates depends critically on the estimated valne of... 

A successful project is defined as one that meets its stated objectives (safety, improved reliability, increased liquid yield, reduced maintenance costs, etc.) on or under-budget and is completed on or ahead of schedule. Some of the helpful criteria that ensure a successful project are as follows ... 

In all liquids, the free-ion yield increases with the external electric field E. An important feature of the Onsager (1938) theory is that the slope-to-intercept ratio (S/I) of the linear increase of free-ion yield with the field at small values of E is given by e3/2efeB2T2, where is the dielectric constant of the medium, T is its absolute temperature, and e is the magnitude of electronic charge. Remarkably S/I is independent of the electron thermalization distance distribution or other features of electron dynamics in fact, it is free of adjustable parameters. The theoretical value of S/I can be calculated accurately with a known value of the dielectric constant it has been well verified experimentally in a number of liquids, some at different temperatures (Hummel and Allen, 1967 Dodelet et al, 1972 Terlecki and Fiutak, 1972). 

With an increase of E beyond a certain value specific to the liquid, the free-ion yield increases sublinearly with the field, eventually showing a saturation trend at very high fields (see Mathieu et al.,1967). Freeman and Dodelet (1973) have shown that a fixed electron-ion initial separation underestimates the free-ion yield at high fields, and that a distribution of thermalization distance must be used to explain the entire dependence of Pesc on E. Therefore, the theoretical problem of the variation of free-ion yield with external field is inextricably mixed with that of the initial distribution of electron-cation separation. 

Pyrolysis dates back to at least ancient Egyptian times, when tar for caulking boats and certain embalming agents were made by pyrolysis. In the 1980s, researchers found that the pyrolysis liquid yield could be increased using fast pyrolysis where a biomass feedstock is heated at a rapid rate and the vapors produced also condensed rapidly (Mohan et al., 2006). 

With respect to partial conversion by flash pyrolysis, the principal consideration in a choice between otherwise equivalent coals is the fact that liquid yields tend to increase with rank up to high volatile bituminous coals and thereafter to fall off sharply. 

The benefits of an improved feed injection system and riser can be lower delta coke, lower regenerator temperature, higher conversion, higher gasoline yield, and increased liquid yield. More feed can be processed and an air blower or wet gas compressor limitation can be relieved. 

Catalyst mass flowrates exceeding about 1600 Ib/ft -min (7800kg/m -min) results in poor steam/catalyst contacting, flooded trays, insufficient catalyst residence time, and increased steam entrainment to the spent catalyst standpipe. This is reflected by the stripper efficiency and catalyst density shown in Figure 7.10. The primary concern is hydrocarbon entrainment to the regenerator leading to loss of product, increased catalyst deactivation, increased delta coke and potential loss of conversion and total liquid yield, and feed rate limitation. A rapid decrease in stripper bed density is an indication that... 

Conversion of polymers and biomass to chemical intermediates and monomers by using subcritical and supercritical water as the reaction solvent is probable. Reactions of cellulose in supercritical water are rapid (< 50 ms) and proceed to 100% conversion with no char formation. This shows a remarkable increase in hydrolysis products and lower pyrolysis products when compared with reactions in subcritical water. There is a jump in the reaction rate of cellulose at the critical temperature of water. If the methods used for cellulose are applied to synthetic polymers, such as PET, nylon or others, high liquid yields can be achieved although the reactions require about 10 min for complete conversion. The reason is the heterogeneous nature of the reaction system (Arai, 1998). 

It is clear that the water activity is of crucial importance for the equilibrium yield in a reversed hydrolysis reaction. As expected, the equilibrium yield increases with decreasing water activity. This has been shown, for example, for the condensation of glucose and octanol [62], esterification of lysophospholipids with fatty acids [29, 63], and in normal lipase-catalyzed esterification reactions [64, 65]. The same situation is observed in ionic liquids [66]. 

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