Arge process

Sasol produces synthetic fuels and chemicals from coal-derived synthesis gas. Two significant variations of this technology have been commercialized, and new process variations are continually under development. Sasol One used both the fixed-bed (Arge) process, operated at about 240°C, as weU as a circulating fluidized-bed (Synthol) system operating at 340°C. Each ET reactor type has a characteristic product distribution that includes coproducts isolated for use in the chemical industry. Paraffin wax is one of the principal coproducts of the low temperature Arge process. Alcohols, ketones, and lower paraffins are among the valuable coproducts obtained from the Synthol process. 

A number of chemical products are derived from Sasol s synthetic fuel operations based on the Fischer-Tropsch synthesis including paraffin waxes from the Arge process and several polar and nonpolar hydrocarbon mixtures from the Synthol process. Products suitable for use as hot melt adhesives, PVC lubricants, cormgated cardboard coating emulsions, and poHshes have been developed from Arge waxes. Wax blends containing medium and hard wax fractions are useful for making candles, and over 20,000 t/yr of wax are sold for this appHcation. 

Results for the Synthol entrained-bed process (16) are plotted in Figure 8. The available C to C15 data follow the conventional Flory plot with a equal to 0.7. The Synthol process uses a fused Fe catalyst of low surface area and porosity and operates at high temperatures ( 590K). The products in the reactor are mainly gaseous, wax formation is minimal, and the pellet pore structure remains free of liquid products therefore, diffusion-enhanced a-olefin readsorption is much less likely than in the ARGE process. Whereas the product selectivity in the ARGE process is altered by diffusion-enhanced a-olefin readsorption, that in the Synthol process is not. 

For comparison, the Fischer Tropsch ARGE process and the methanol synthesis are running in boiling water reactors with a tube diameter of ca. 40 mm. The required tube length is 7.5 and 1 km/t product/h for the two syntheses, respectively. 

Sasol Conventional steam-reforming catalysts. 1. ARGE process. Iron catalyst. 2. Advanced Synthol. Iron catalyst. 3. SSPD process. Cobalt or iron catalyst. 

Recent advances in Eischer-Tropsch technology at Sasol include the demonstration of the slurry-bed Eischer-Tropsch process and the new generation Sasol Advanced Synthol (SAS) Reactor, which is a classical fluidized-bed reactor design. The slurry-bed reactor is considered a superior alternative to the Arge tubular fixed-bed reactor. Commercial implementation of a slurry-bed design requires development of efficient catalyst separation techniques. Sasol has developed proprietary technology that provides satisfactory separation of wax and soHd catalyst, and a commercial-scale reactor is being commissioned in the first half of 1993. 

In 1991, the relatively old and small synthetic fuel production faciHties at Sasol One began a transformation to a higher value chemical production facihty (38). This move came as a result of declining economics for synthetic fuel production from synthesis gas at this location. The new faciHties installed in this conversion will expand production of high value Arge waxes and paraffins to 123,000 t/yr in 1993. Also, a new faciHty for production of 240,00 t/yr of ammonia will be added. The complex will continue to produce ethylene and process feedstock from other Sasol plants to produce alcohols and higher phenols. 

Since the proline residue in peptides facilitates the cyclization, 3 sublibraries each containing 324 compounds were prepared with proline in each randomized position. Resolutions of 1.05 and 2.06 were observed for the CE separation of racemic DNP-glutamic acid using peptides with proline located on the first and second random position, while the peptide mixture with proline preceding the (i-alamine residue did not exhibit any enantioselectivity. Since the c(Arg-Lys-0-Pro-0-(i-Ala) library afforded the best separation, the next deconvolution was aimed at defining the best amino acid at position 3. A rigorous deconvolution process would have required the preparation of 18 libraries with each amino acid residue at this position. 

However, the use of a HPLC separation step enabled a remarkable acceleration of the deconvolution process. Instead of preparing all of the sublibraries, the c(Arg-Lys-O-Pro-O-P-Ala) library was fractionated on a semipreparative HPLC column and three fractions as shown in Fig. 3-2 were collected and subjected to amino acid analysis. According to the analysis, the least hydrophobic fraction, which eluted first, did not contain peptides that included valine, methionine, isoleucine, leucine, tyrosine, and phenylalanine residues and also did not exhibit any separation ability for the tested racemic amino acid derivatives (Table 3-1). 

L. Seglin Why has Lurgi selected the hot gas recycle process for methanation rather than the isothermal reactor (ARGE) design which they used for the Fischer-Tropsch plant in SASOL s plant in South Africa ... 

Furin, also known as paired basic amino-acid-cleaving enzyme (PACE), is a membrane bound subtilisin-like serine protease of the irons Golgi compartment. It is ubiquitously expressed and mediates processing of many protein precursors at Arg-X-Lys/Arg-Arg sites. 

The design of the Sasol 1 facility in Sasolburg, South Africa, was the result of a compromise between the experience that accompanied the Fe-LTFT processes from the Arbeitsgemeinschaft Ruhrchemie-Lurgi (Arge) in Germany and the economy of the Fe-HTFT process from Kellogg in the United States.28 The Sasol... 

The Arge Fe-LTFT syncrude (Table 18.8)29 was much heavier than the syncrude of the two German Co-LTFT processes (Table 18.2). The Arge Fe-LTFT syncrude exemplified a high a-value Fischer-Tropsch product with a significant linear paraffinic wax fraction. The syncrude (Table 18.8) from the Kellogg Fe-HTFT synthesis was very similar in carbon number distribution to that of Hydrocol Fe-HTFT synthesis (Table 18.5). 

The selection of a fixed bed Co-LTFT process supported the objective to apply the SMDS process for beneficiation of remote gas fields. The Co-LTFT catalyst has a useful lifetime of 5 years and the robustness of fixed bed reactor technology has been proven. For example, the fixed bed Arge Fe-LTFT process has now been in operation for more than 50 years at Sasol 1. 

Additional endoproteases may be shown to play a role in neuropeptide biosynthesis. Leading candidates are the mammalian homolog of the yeast aspartyl protease-3 (YAP-3) and a thiol protease. The processing of proANF, which involves cleavage after a single Arg residue in proANF, cannot involve PCI or PC2 since there are negligible amounts of these PCs in the heart. 

SSPD [Sasol slurry phase distillate] A process for converting natural gas to diesel fuel, kerosene, and naphtha. Operated by Sasol in South Africa since 1993. Three stages are involved. In the first, natural gas is converted to synthesis gas by reforming. In the second, the synthesis gas is converted to waxy hydrocarbons in a slurry-phase reactor. In the third, the waxes are upgraded to middle distillates. See also Arge. 

Amino Acid Content. Amino acid content of field pea products is related to protein level, method of processing, and fraction (starch or protein). The protein fraction contains fewer acidic (glu, asp) amino acids than the starch fraction and more basic (lys, his, arg) amino acids than the starch fraction. Also, there are more aromatic (tyr, phe) amino acids, leu, iso, ser, val, and pro in the protein fraction than in the starch fraction (5). An amino acid profile of pea protein concentrate shows relatively high lysine content (7.77 g aa/16 g N) but low sulfur amino acids (methionine and cystine) (1.08-2.4 g aa/16 g N). Therefore, it is recommended that air classification or ultrafiltration be used because acid precipitation results in a whey fraction which contains high levels of sulfur amino acids (12,23). Also, drum drying sodium proteinates decreases lysine content due to the Maillard reaction (33). 

In addition to their chemotactic activity, C5-derived peptides can also induce degranulation in human neutrophils. This process, readily detected in cytochalasin-B-treated neutrophils, occurs rapidly (within 1 min) upon the addition of peptides. The half-maximum responses in cytochalasin-treated human neutrophils are observed at 1-5 nM C5a and 100-800 nM C5a des Arg. In the absence of cytochalasin B, degranulation can still be detected (albeit at lower rates), especially if the neutrophils are adherent prior to the... 

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