Product Slate Research Articles

Reactivity of Bis(2,2,5,5-tetramethyl-2,5-disila-1-azacyclopent-1-yl)tin with CO2, OCS, and CS2 and Comparison to That of Bis[bis(trimethylsilyl)amido]tin

The heterocumulenes carbon dioxide (CO(2)), carbonyl sulfide (OCS), and carbon disulfide (CS(2)) were treated with bis(2,2,5,5-tetramethyl-2,5-disila-1-azacyclopent-1-yl)tin {[(CH(2))Me(2)Si](2)N}(2)Sn, an analogue of the well-studied bis[bis(trimethylsilyl)amido]tin species [(Me(3)Si)(2)N](2)Sn, to yield an unexpectedly diverse product slate. Reaction of {[(CH(2))Me(2)Si](2)N}(2)Sn with CO(2) resulted in the formation of 2,2,5,5-tetramethyl-2,5-disila-1-oxacyclopentane, along with Sn(4)(μ(4)-O){μ(2)-O(2)CN[SiMe(2)(CH(2))(2)]}(4)(μ(2)-N═C═O)(2) as the primary organometallic Sn-containing product. The reaction of {[(CH(2))Me(2)Si](2)N}(2)Sn with CS(2) led to formal reduction of CS(2) to [CS(2)](2-), yielding [{[(CH(2))Me(2)Si](2)N}(2)Sn](2)CS(2){[(CH(2))Me(2)Si](2)N}(2)Sn, in which the [CS(2)](2-) is coordinated through C and S to two tin centers. The product [{[(CH(2))Me(2)Si](2)N}(2)Sn](2)CS(2){[(CH(2))Me(2)Si](2)N}(2)Sn also contains a novel 4-membered Sn-Sn-C-S ring, and exhibits a further bonding interaction through sulfur to a third Sn atom. Reaction of OCS with {[(CH(2))Me(2)Si](2)N}(2)Sn resulted in an insoluble polymeric material. In a comparison reaction, [(Me(3)Si)(2)N](2)Sn was treated with OCS to yield Sn(4)(μ(4)-O)(μ(2)-OSiMe(3))(5)(η(1)-N═C═S). A combination of NMR and IR spectroscopy, mass spectrometry, and single crystal X-ray diffraction were used to characterize the products of each reaction. The oxygen atoms in the final products come from the facile cleavage of either CO(2) or OCS, depending on the reacting carbon dichalogenide.

Effective Gasoline Production Strategies by Catalytic Cracking of Rapeseed Vegetable Oil in Refinery Conditions

Effective Gasoline Production Strategies by Catalytic Cracking of Rapeseed Vegetable Oil in Refinery Conditions

Pyrolysis of fast-growing aquatic biomass – Lemna minor (duckweed): Characterization of pyrolysis products

The aim of this work was to conduct the experimental study of pyrolysis of fast-growing aquatic biomass – Lemna minor (commonly known as duckweed) with the emphasis on the characterization of main products of pyrolysis. The yields of pyrolysis gas, pyrolytic oil (bio-oil) and char were determined as a function of pyrolysis temperature and the sweep gas (Ar) flow rate. Thermogravimetric/differential thermogravimetric (TG/DTG) analyses of duckweed samples in inert (helium gas) and oxidative (air) atmosphere revealed differences in the TG/DTG patterns obtained for duckweed and typical plant biomass. The bio-oil samples produced by duckweed pyrolysis at different reaction conditions were analyzed using GC–MS technique. It was found that pyrolysis temperature had minor effect on the bio-oil product slate, but exerted major influence on the relative quantities of the individual pyrolysis products obtained. While, the residence time of the pyrolysis vapors had negligible effect on the yield and composition of the duckweed pyrolysis products.

Approaches and Software Tools for Modeling Lignin Pyrolysis†

The integration of the Attribute Reaction Modeling approach with the CompGen and KME kinetic modeling tools is described through the development of a kinetic model for lignin pyrolysis. Lignin structure is described as the juxtaposition of a methoxy phenol (MP) and a propanoid side chain (PC) attribute at para positions on an aromatic ring. The CompGen tool provides the qualitative list and the quantitative composition of the attributes in the reactant lignin. Pyrolysis alters the state of the MP and PC attributes while leaving the aromatic ring conserved. These reactions are described in two KME submodels, one for each attribute. The juxtaposition of the reaction-altered attributes defines the product slate. This modeling approach describes the full composition of 624 molecules with 50 equations. The user-friendly CompGen and KME tools allow for the construction of the initial conditions and attribute model equations in a spreadsheet environment enhanced with Visual Basic code that creates, compiles and executes the underlying C code.

An Assessment of Gasification-Based Biorefining at Kraft Pulp and Paper Mills in the United States, Part B: Results

Commercialization of black liquor and biomass gasification technologies is anticipated in the 2010–2015 timeframe, and synthesis gas from gasifiers can be converted into liquid fuels using catalytic synthesis technol-ogies that are already commercially established today in the gas-to-liquids or coal-to-liquids industries. This set of two papers describes key results from a major assessment of the prospective energy, environmental, and financial performance of commercial gasification-based biorefineries integrated with kraft pulp and paper mills. Seven detailed biorefinery designs were developed for a reference mill in the southeastern United States, together with the associated mass/energy balances, air emissions estimates, and capital investment requirements. The biorefineries provide chemical recovery services and co-produce process steam for the mill, some electricity, and one of three liq-uid fuels: a Fischer-Tropsch synthetic crude oil (which could be refined to vehicle fuels at an existing petroleum refin-ery), dimethyl ether (a diesel engine fuel or propane substitute), or an ethanol-rich mixed-alcohol product. Compared with installing new Tomlinson power/recovery systems, biorefineries would require more capital investment and greater purchases of woody residues for energy use. However, because biorefineries would be more efficient, have lower air emissions, and produce a more diverse product slate, for nearly all cases examined, the internal rate of return (IRR) on the incremental capital investment lies between 14% and 18%, assuming a $50/bbl world oil price. The IRRs would more than double if plausible federal and state financial incentives were captured. Industry-wide adoption of such biorefining in the United States would provide significant energy and environmental benefits to the country.

The Hydrocarbon Pool in Ethanol-to-Gasoline over HZSM-5 Catalysts

It is shown that the conversion of ethanol-to-gasoline over an HZSM-5 catalyst yields essentially the same product distribution as for methanol-to-gasoline performed over the same catalyst. Interestingly, there is a significant difference between the identity of the hydrocarbon molecules trapped inside the HZSM-5 catalyst when ethanol is used as a feed instead of methanol. In particular, the hydrocarbon pool contains a significant amount of ethylsubstituted aromatics when ethanol is used as feedstock, but there remains only methyl-substituted aromatics in the product slate.

Structural characterization of FCC feeds from Indian refineries by NMR spectroscopy

Fluid catalytic cracking (FCC) feeds from four Indian refineries are structurally characterized by 1H, gated-decoupled 13C, distortionless enhancement by polarization transfer (DEPT) and 2D 1H–13C HETeronuclear CORrelation (HETCOR) and other 2D nuclear magnetic resonance (NMR) methods. Detailed structural analyses are completely supported by a range of NMR information including chemical shifts of 1H and 13C, CHn type distributions and 1H –13C connectivities. The average structural parameters like branching sites, average number of branching per molecule, average length of side chains, percentage of saturates, aromatics and naphthenes are obtained from these NMR data. A novel approach based on “multipoint spline base line correction” is employed for estimation of naphthenes and n-paraffins that gives better quantitative estimation than the conventional methods. In this paper, importance is given to the study of those structural parameters that plays a key role in cracking chemistry as well as coke forming tendency of the feedstock. To the best of our knowledge, this is the first attempt to characterize and quantitatively estimate compositions of the high boiling fractions of petroleum feed by NMR methods and especially the complex structure of vacuum gas oil (VGO) fractions used in Indian refineries. The importance of this paper is to help in optimizing the product slate of Indian refineries through proper feedstock blending using few hundreds of million metric tons (MMT) of crude oil consisting of blends of light crudes with different heavy crudes and bottom of the barrel due to escalating cost of crudes.

Fuel-Blending Stocks from the Hydrotreatment of a Distillate Formed by Direct Coal Liquefaction

The direct liquefaction of coal in the iron-catalyzed Suplex process was evaluated as a technology complementary to Fischer−Tropsch synthesis. A distinguishing feature of the Suplex process, from other direct liquefaction processes, is the use of a combination of light- and heavy-oil fractions as the slurrying solvent. This results in a product slate with a small residue fraction, a distillate/naphtha mass ratio of 6, and a 65.8 mass % yield of liquid fuel product on a dry, ash-free coal basis. The densities of the resulting naphtha (C5−200 °C) and distillate (200−400 °C) fractions from the hydroprocessing of the straight-run Suplex distillate fraction were high (0.86 and 1.04 kg/L, respectively). The aromaticity of the distillate fraction was found to be typical of coal liquefaction liquids, at 60−65%, with a Ramsbottom carbon residue content of 0.38 mass %. Hydrotreatment of the distillate fraction under severe conditions (200 °C, 20.3 MPa, and 0.41 gfeed h-1 gcatalyst-1) with a NiMo/Al2O3 catalyst gave...

Attempts To Improve the Product Slate Quality: Influence of Coke-on-Catalyst Content

Several catalysts with increasing initial coke content were processed in the Microdowner unit in order to assess the activity and selectivity of coked catalyst. Tests were carried out at both constant operating conditions and changing catalyst-to-oil ratio to maintain conversion. It was found that coke on regenerated catalyst (CRC) has very little influence on the main product selectivity, while some effect on product quality was detected. CRC changed the hydrogen transfer to cracking relative rate as it lowered site density, resulting in a dramatic increase in the isobutene-to-isobutane ratio. Gasoline was more olefinic and less paraffinic, while sulfur content increased. LCO yield increased slightly, producing a distillate with better quality (fewer aromatics and more paraffins). When ZSM5 is used, it has been observed that propylene selectivity increases at constant conversion at a rate around 1 point of propylene per percent coke on catalyst. Apart from the cracking selectivity changes in the riser, the significant increase in catalyst circulation that is necessary to maintain conversion may have some beneficial effects for feed vaporization and reduced thermal cracking at the injection point.

Serono Eyes Strategic Shake-Up

Swiss biotechnology company Serono, which is 62% owned by the founding Bertarelli family, says it has retained investment firm Goldman Sachs to explore various strategic alternatives. Serono isn't commenting further, but such an announcement usually implies that a company has decided to put itself up for sale. Indeed, press reports say Serono has talked with at least four major pharmaceutical companies about being acquired, a deal that could be worth up to $15 billion. Industry observers point out, though, that Serono's move could indicate the opposite decision: that it is putting together an acquisition strategy of its own. Serono's multiple sclerosis treatment, Rebif, accounted for 54% of its sales in the first three quarters of 2005. That relatively limited product slate—and a limited pipeline of new drugs, particularly in late-stage clinical development-may put off prospective buyers, some analysts conjecture. They suggest that Serono could instead embark on an acquisition-driven push to broaden its...

Influence of the Reaction Temperature and pH on the Coordination Modes of the 1,4-Benzenedicarboxylate (BDC) Ligand: A Case Study of the NiII(BDC)/2,2‘-Bipyridine System

Three new Ni(BDC)/2,2'-bipy compounds, Ni2(BDC)(HBDC)2(2,2'-bipy)2 (2), Ni3(BDC)3(2,2'-bipy)2 (3), and Ni(BDC)(2,2-bipy)2.2H2O (5), in addition to the previously reported Ni(BDC)(2,2'-bipy).0.75H2BDC (1) and Ni(BDC)(2,2'-bipy)(H2O) (4) [BDC = 1,4-benzenedicarboxylate; 2,2'-bipy = 2,2'-bipyridine], have been synthesized by hydrothermal reactions. A systematic investigation of the effect of the reaction temperature and pH resulted in a series of compounds with different compositions and dimensionality. The diverse product slate illustrates the marked sensitivity of the structural chemistry of polycarboxylate aromatic ligands to synthesis conditions. Compound 1, which has a channel structure containing guest H2BDC molecules, is formed at the lowest pH. The guest H2BDC molecules are connected by hydrogen bonds and form extended chains. At a slightly higher pH, a dimeric molecular compound 2 is formed with a lower number of protonated carboxylate groups per nickel atom and per BDC ligand. Reactions at higher temperature and the same pH lead to the transformation of 1 and 2 into the two-dimensional, layered trinuclear compound 3. As the pH is increased, a one-dimensional polymer 4 is formed with a water molecule coordinated to Ni2+. Bis-monodentate and bischelating BDC ligands alternate along the chain to give a crankshaft rather than a regular zigzag arrangement. A further increase of the pH leads to the one-dimensional chain compound 5, which has two chelating 2,2'-bipy ligands. Crystal data: 2, triclinic, space group P, a = 7.4896(9) angstroms, b = 9.912(1) angstroms, c = 13.508(2) angstroms, alpha = 86.390(2) degrees , beta = 75.825(2) degrees, gamma = 79.612(2) degrees, Z = 2; 3, orthorhombic, space group Pbca, a = 9.626(2) angstroms, b = 17.980(3) angstroms, c = 25.131(5) angstroms, Z = 4; 5, orthorhombic, space group Pbcn, a = 14.266(2) angstroms, b = 10.692(2) angstroms, c = 17.171(2) angstroms, Z = 8.

Integration of the Total Petrochemicals-UOP olefins conversion process into a naphtha steam cracker facility

Integration of the Total Petrochemicals-UOP olefins conversion process (OCP) into a conventional naphtha steam cracker allows maximizing the propylene to ethylene yield ratio while converting olefinic feedstocks such as Raf 2, Raw C4s, HT Raw C4s and light FCC gasoline. Comparisons are made between the product yields obtained from these olefinic streams through conventional steam cracking, and the combined yields when the olefinic feedstocks are first converted on an OCP process and the C4+ product further processed on a steam cracker furnace OCP as a feed-pretreatment for steam cracking of olefinic feedstocks allows shifting the P/E ratio in the global product slate to values well outside the normal ranges observed on SR naphtha. In an existing steam cracker that is furnace limited, the concept may permit to increase the propylene yield dramatically. The highest potential is observed when the plant has no other option than to recycle crack the Raw C4s.

Employ NMP Extraction for Value Addition of Waxy Streams

With rising crude oil prices, coupled with tightening product specifications and environmental concerns, the refining industry will continue to see many changes during the times to come. In order to maintain/improve their margins, refiners are obliged to upgrade the low value streams into more profitable products. For upgrading the existing product slate, or manufacture of new products, huge investments are needed for new facilities. This involves logistic and proper evaluation of all the possible upgrading technologies and optimal processing schemes in order to arrive at the best option for a particular unit. This study deals with NMP extraction studies on two vacuum cuts; namely, pressible and heavy waxy distillates (PWD and HWD) for their up-gradation into raffinates of desired hydrocarbon composition and extracts of high aromaticity (BMCI). Solvent extraction studies were carried out on multistage extraction column in countercurrent mode. The water content in the solvent was optimized and kept the same for both the streams for ease of solvent recovery. The extraction conditions such as temperature, solvent-to-feed ratio, and water content in solvent were optimized for high quality raffinate and high quality aromatic extract (BMCI > 105). Studies reveal that the processing of PWD and HWD produces raffinate that could be used as feedstocks to solvent dewaxing/de-oiling unit for paraffin wax production. The high BMCI extract can be used as feed for high value industrial carbons such as pitches and needle coke. An added advantage of following this scheme is that the filtration rates of the NMP extracted PWD and HWD raffinates increase by ∼ 50% in comparison to that of raw distillates, thereby leading to capacity enhancement besides easy finishing of the wax. Moreover, withdrawal of about 25% of aromatic extracts from PWD and HWD feed stocks would lead to increase in capacity of the wax dewaxing/deoiling unit.

Process synthesis optimization and flexibility evaluation of air separation cycles

AbstractThe solution is discussed of the process synthesis problem for cryogenic air separation using techniques from process synthesis optimization. The mass and energy balances for the process are represented by a simplified algebraic model in which material stream flows and pressures appear as continuous variables and the various equipment choices for components of the air separation cycle are represented by binary variables. The resulting model corresponds to a mixed‐integer nonlinear programming (MINLP) formulation and enables numerical optimization of the cycle. The two problems addressed are the selection of the optimal equipment set for a given product slate and the flexibility determination of the chosen cycle. The flexibility analysis is complemented with unique visual techniques that depict the feasible region and use of the recently proposed convex‐hull approach. The calculations are illustrated for low‐purity (95%) oxygen plants using the Lachmann cycle. © 2005 American Institute of Chemical Engineers AIChE J, 2005

Inventory evaluation and product slate management in large-scale continuous process industries

Managing production and inventory for large-scale continuous processing plants is a key to success in the chemical process industry, particularly in the production of commodity polymers such as polyethylene and polypropylene. When setting up a production schedule, planners must consider the effects of off-grade production and production rate penalties, which are typically sequence-dependent as products are transitioned from one to another, as well as inventory holding costs and capacity constraints. We call this the continuous economic lot sizing and scheduling problem (CELSP) to distinguish it from closely related problems found in discrete part production industries. We present a formulation that addresses the particular aspects of the CELSP and apply the proposed mathematical modeling approach to several plants of a chemical processing company. This company was concerned with ensuring the plants were carrying proper amounts of inventory and with evaluating the number of products produced at each plant. Our results show actual overall inventory levels were close to the levels suggested by our model and therefore company plans for further inventory reductions would not be appropriate. However, the company should carefully consider the addition of new products to current plant product slates. Due to the effects of product transitions and inventory levels, even adding products with significant contribution margins may negatively affect the financial performance of the plant.

Depolymerization Study of Pakistani Lignite Coal Influence of Pre‐treatments on Product Slate

AbstractInfluence of pretreatments, i.e., demineralization and pre‐soaking in some solvents on the yields of liquefied products obtained from hydro‐depolymerization of Pakistani coal in a pool of hydrogen has been discussed. Results of hydrogenation experiments demonstrated that demineralizing the coal sample prior to liquefaction caused the yields to decrease compared with the virgin coal samples. The contribution of mineral matter of coal has been evaluated by comparing the yields of liquid products of virgin and leached samples. Increase in the yields obtained from the hydrogenation experiments of swollen coal samples was not satisfactorily significant.

Laboratory-Scale Coking of Coal−Petroleum Mixtures in Sealed Reactors

Three highly fluid bituminous coals-from the Pittsburgh, Powellton, and Eagle seams-were reacted with atmospheric resid and decant oil in microautoclave reactors under nitrogen at temperatures of 450-500 °C. This exploratory study is the first step in evaluating the prospects for adding coal to delayed cokers to obtain coal-derived components in the liquid product. Subsequent hydrotreating (not studied here) of the liquid would produce a jet fuel with good stability toward pyrolytic decomposition. Coal-derived components appear in the oil fraction from coal-resid reactions at 465 °C. This reaction temperature represents a coke jump, in which the yield of solid, as a function of temperature, increases dramatically. This behavior is not observed when the individual feedstocks are reacted alone. Further evidence for coal-petroleum interactions in this system is exhibited by the fact that (i) the product slates from the co-coking reactions are not linear combinations of the products from the feedstocks reacted individually and (ii) the fluidity profiles of the Powellton-resid mixtures are similar to those for two interacting coking coals. The effect of changing coal with the same petroleum feedstock is minimal, although the coals are very similar in composition and properties. In contrast, changing from resid to decant oil with the same coal causes major changes in the product slate.

Does glucose enhance the formation of nitrogen containing polycyclic aromatic compounds and polycyclic aromatic hydrocarbons in the pyrolysis of proline?

The gas-phase pyrolysis of proline, glucose, 1-[(2′-carboxy)pyrrolidinyl]-1-deoxy- d-fructose (the proline Amadori compound), and a 1:1 mixture by weight of proline and glucose was investigated at high temperatures (600–840 °C) and short residence time (i.e. 1.0 s) in an inert atmosphere to determine if glucose or Maillard reaction products enhance the formation of nitrogen containing polycyclic aromatic compounds (N-PACs) and polycyclic aromatic hydrocarbons (PAHs) in the pyrolysis of proline. To study the gas-phase formation of N-PACs and PAHs, the substrates were sublimed into the pyrolysis furnace at 460 °C. Thermogravimetric analysis showed that glucose, the proline/glucose mixture, and the proline Amadori compound undergo solid-state decomposition reactions before subliming. Thus, the substrates were pyrolyzed in two stages: at 460 °C during the sublimation and at 600–840 °C. At 800 °C with a residence time of 1.0 s, proline produced low yields of N-PACs, such as quinoline, isoquinoline, indole, acridine, and carbazole, and PAHs, such as phenanthrene, pyrene, benz[ a]anthracene, benzofluoranthene isomers, and benzo[ a]pyrene. Increasing the temperature and residence time increased the yield of these products. Under similar pyrolysis conditions, the proline Amadori compound produced 2–8 fold more N-PACs and PAHs than proline. A 1:1 mixture of proline and glucose produced a similar slate of pyrolysis products as the proline Amadori compound, but it is unclear whether the proline Amadori compound was an intermediate in the reaction. In general, the proline Amadori compound produced a higher yield of N-PACs and PAHs than the proline/glucose mixture, but glucose clearly enhances the low temperature gas-phase formation of N-PACs and PAHs from the pyrolysis of proline. For example, a 1:1 mixture of proline and glucose was found to produce low yields of quinoline, isoquinoline, and indole at 600 °C while proline alone does not produce these compounds until 800 °C. Thus, glucose provides a low temperature pathway for the decomposition of proline, which leads to formation of N-PACs and PAHs.

Relating Feedstock Composition to Product Slate and Composition in Catalytic Cracking. 6. Feedstocks Derived from Merey, a Venezuelan Crude

Relating Feedstock Composition to Product Slate and Composition in Catalytic Cracking. 6. Feedstocks Derived from Merey, a Venezuelan Crude

Polymer industry and innovation in macromolecule science and technology in china

AbstractThe paper describes the recent technological progress in synthetic resin, synthetic fiber and synthetic rubber in China, as well as the achievements obtained in process technology development, catalyst R&D, the adjustment of product slate, and product capacity and output. Also, in the paper, an expectation image of next decade has been drawn.