Abstract:
An energy-efficient extractive distillation process for producing anhydrous ethanol from aqueous/ethanol feeds containing any range of ethanol employs an extractive distillation column (EDC) that operates under no or greatly reduced liquid reflux conditions. The EDC can be incorporated into an integrated process for producing anhydrous ethanol used for gasoline blending from fermentation broth. By using a high-boiling extractive distillation solvent, no solvent is entrained by the vapor phase to the EDC overhead stream, even under no liquid reflux conditions. The energy requirement and severity of the EDC can be further improved by limiting ethanol recovery in the EDC. In this partial ethanol recovery design, ethanol which remains in the aqueous stream from the EDC is recovered in a post-distillation column or the aqueous stream is recycled to a front-end pre-distillation column where the ethanol is readily recovered since the VLE curve for ethanol/water is extremely favorable for distillation.
Abstract:
An improved oxidative process that employ a robust, non-aqueous, and oil-soluble organic peroxide oxidant for effective desulfurization and denitrogenation of hydrocarbons including petroleum fuels, hydrotreated vacuum gas oil (VGO), non-hydrotreated VGO, petroleum crude oil, synthetic crude oil from oil sand, and residual oil. Even at low concentrations and without the assistance of catalysts, the non-aqueous organic peroxide oxidant is extremely active and fast in oxidizing the sulfur and nitrogen compounds in the hydrocarbon feedstocks. Furthermore, the process generates a valuable organic acid by-product that is also used internally as the extractive solvent for effective removal of the oxidized sulfur and nitrogen from the hydrocarbons without the need of a final adsorption step. Novel process steps are also disclosed to substantially prevent yield loss in the oxidative process.
Abstract:
A method and apparatus for purifying crude terephthalic acid from a liquid dispersion thereof also containing impurities selected from unreacted starting materials, solvents, products of side reactions and/or other undesired materials is provided. The method comprises the steps of filtering the dispersion to form a crude terephthalic acid filter cake, dissolving the filter cake in a selective crystallization solvent at an elevated temperature to form a solution, crystallizing purified terephthalic acid from the solution in the crystallization solvent by reducing the pressure and temperature of the solution, and separating the crystallized purified terephthalic acid from the solution. According to the invention, the selective crystallization solvent is non-aqueous, non-corrosive and essentially non-reactive with terephthalic acid. Preferably, the selective crystallization solvent is N-methyl pyrrolidone. The method and apparatus produces purified terephthalic acid having a purity desired for use in forming polyester resin and other products at an economically attractive rate and at operating conditions of reduced severity which require a lower capital investment and simplified processing.
Abstract:
A method and apparatus for purifying crude terephthalic acid from a liquid dispersion thereof also containing impurities selected from unreacted starting materials, solvents, products of side reactions and/or other undesired materials is provided. The method comprises the steps of filtering the dispersion to form a crude terephthalic acid filter cake, dissolving the filter cake in a selective crystallization solvent at an elevated temperature to form a solution, crystallizing purified terephthalic acid from the solution in the crystallization solvent by reducing the temperature of the solution, and separating the crystallized purified terephthalic acid from the solution. According to the invention, the selective crystallization solvent is non-aqueous, non-corrosive and essentially non-reactive with terephthalic acid. Preferably, the selective crystallization solvent is N-methyl pyrrolidone. The method and apparatus produces purified terephthalic acid having a purity desired for use in forming polyester resin and other products at an economically attractive rate and at operating conditions of reduced severity which require a lower capital investment and simplified processing.
Abstract:
A method for reducing carboxybenzaldehyde isomers in crude terephthalic and/or isophthalic acids is described. Crude TPA or IPA is dissolved in N-methyl pyrrolidone and is subsequently contacted with an oxidant, such as substantially anhydrous hydrogen peroxide, to convert the carboxybenzaldehyde isomer (4-CBA or 3-CBA) to TPA or IPA under moderate temperature and pressure conditions.
Abstract:
Disclosed is a process for removing acid soluble oils, produced as an undesirable by-product of an HF catalyzed alkylation reaction, from a liquid containing a sulfone compound. The process includes the use of a solvent to extract the acid soluble oils from a sulfone-containing fluid that has previously been neutralized by a treating step.
Abstract:
An extractive distillation process for separation ethers (in particular methyl t-butyl ether or ethyl t-butyl ether), aliphatic hydrocarbons (in particular isobutane and/or isobutene) and alcohols (in particular methanol or ethanol) employs as solvent sulfolane(s) and/or dialkyl sulfone(s), or N-(.beta.-mercaptoalkyl)-2-pyrrolidone(s), or a mixture of N-alkyl-2-pyrrolidone(s) and either sulfolane(s) or glycol compound(s).
Abstract:
The separation of alkadienes from close-boiling alkenes by extractive distillation employes as solvent N-methyl-2-thiopyrrolidone, alone or in admixture with unsubstituted sulfolane (cyclotetramethylene sulfone), or a mixture of unsubstituted sulfone and N-methyl-2-pyrrolidone. The separation of cycloalkadienes from close-boiling alkadienes by extractive distillation employs N-methyl-2-thiopyrrolidone as solvent.
Abstract:
A process for catalytically cracking a hydrocarbon-containing feed stream, preferably having an API.sup.60 gravity of about 5-30, wherein at least a portion of off-gases is treated so as to remove C.sub.2 -C.sub.4 olefins therefrom, and the off-gas stream having a reduced olefin content is then recycled to the catalytic cracking zone.
Abstract:
A high capacity magnetic filter separates diamagnetic and/or paramagnetic substances from fluid streams. Diamagnetic solid substances are magnetized under an external magnetic field through coordinated interaction of diamagnetic solid substances with an inducement paramagnetic material (IPM). The magnetic filter serves as a separation zone created by the presence of IPM and magnets that are shielded from the IPM by non-magnetic sleeves or partitions. The IPM in the void volume between the magnets affords large surface area onto which diamagnetic and paramagnetic materials can contact and be attracted to. The relative position and distance of the magnetic source, such a magnetic bar or electromagnet, to the solid mixture of diamagnetic and IPM are adjusted to induce sufficiently strong magnetism in the diamagnetic solids which causes the diamagnetic solids to be attracted by the magnetic field as well. Both diamagnetic and paramagnetic substances can be removed from a liquid or gas.