Shell Oil Comapny

Charles C Chou

Harold J Vinegar

Eric Pierre De Rouffignac

Paul C Johnson

Arthur L Otermat

Chaoliang Yao

George Leo Stegemeier

Donald R Kelsey

Donald C Olson

David A Weingaertner

Stephen Merle Stearns

Arnold R Marsden, Jr

Dallas Lea Byers

George M Deeley

Joseph J Gentempo

James D Colthart

George L Stegmeier

A process for preparing a 1,3-propanediol-based polyester comprises contacting an aqueous stream containing acrolein byproduct with a base for a time effective to reduce the acrolein content of the aqueous stream. In a specific embodiment, a poly(propylene terephthalate) preparation process comprises the steps of: (a) contacting 1,3-propanediol and terephthalic acid at elevated temperature to produce a reaction product mixture comprising a poly(propylene terephthalate) and an aqueous solution comprising acrolein; (b) removing a major portion of the aqueous solution from said reaction product mixture; (c) adding a sufficient quantity of a base to the aqueous solution to form a basic solution having a pH greater than about 7.5 and maintaining the basic solution for a time effective to lower the acrolein content thereof; (d) optionally, diluting the basic solution with water; and (e) optionally, biotreating the dilute basic solution for a time effective to further lower the acrolein content. The process of the invention provides a polyester byproduct stream containing reduced levels of acrolein.

By product stream purification in the preparation of

A process for removing Total Reduced Sulfur compounds from a gaseous stream such as those containing natural gas, industrial gas, and digester gas by oxidation with a fine flocculent acidic catalyst slurry which is regenerable during the process by pH adjustment in the absence of added heat. The catalyst slurry comprises MnO.sub.2, Mn.sub.2 O.sub.3, and Mn.sub.3 O.sub.4 having pH in the range from about 0.5 to about 6.5 and is prepared by oxidizing a divalent manganous salt in an aqueous solution having a pH in the range from about 8.0 to about 13.5 with an oxygen-containing gaseous stream.

Process for removing total reduced sulfur compounds from gaseous stream

A process for removing NO.sub.x and/or SO.sub.x from a gaseous stream by oxidation with a fine flocculent acidic catalyst slurry which is regenerable during the process, in particular by pH adjustment in the absence of added heat. The catalyst slurry comprises MnO.sub.2, Mn.sub.2 O.sub.3, and Mn.sub.3 O.sub.4 having pH in the range from about 0.5 to about 6.5 and is prepared by aerating a divalent manganous salt in an aqueous solution having a pH in the range from about 8.0 to about 13.5.

Process for removing nitrogen oxides and sulfur oxides from gaseous

An in situ method for removal of contaminants from soil imposes a vacuum on the soil through perforated heater wells that are positioned in the soil. The heater wells heat the soil to elevated temperatures by thermal conduction. The heater wells are permeable to vapors which emanate from the soil when heated and which are drawn towards the heater wells by the imposed vacuum. An impermeable flexible sheeting on the soil surface reduces the amount of air that is being pulled into the heater well from the atmosphere. A thermal insulator covers the soil surface and reduces heat losses from the soil surface. The heater wells are connected to a vacuum manifold for collection of vapors. A heat front moves away from the heater wells through the soil by thermal conduction, and the superposition of heat from a plurality of heater wells results in a more uniform temperature rise throughout the well pattern. Soil contaminants are removed by vaporization, in situ thermal decomposition, oxidation, combustion, and by steam distillation. Both the presence of water vapor and the low pressure results in vaporization of the contaminants at temperatures well below their normal boiling points. Moreover, the heater wells and the nearby soil are extremely hot and most contaminants drawn into the wells will decompose with a residence time of the order of seconds. The heater well can also be packed with a catalyst that accelerates high temperature decomposition into simpler molecules. Water vapor and remaining contaminants may be incinerated in line or may be collected in a cold trap upstream from the vacuum pump.

Vacuum method for removing soil contaminants utilizing thermal

The top layers of soil contaminated with halogenated organic chemicals are remediated by initial heating at moderate temperature and reduced pressure to remove soil moisture and volatile contaminants and subsequently heating the soil of minimum clay content or acidity at higher temperature, thereby decomposing the halogenated organic chemicals contained therein. Means for effecting such remediation is provided which includes a heat source, pressure regulating means, and vapor collection and treatment means.

Soil decontamination

An in situ method for removal of contaminants from soil imposes a vacuum on the soil through perforated heater wells that are positioned in the soil. The heater wells heat the soil to elevated temperatures by thermal conduction. The heater wells are permeable to vapors which emanate from the soil when heated and which are drawn toward the heater wells by the imposed vacuum. An impermeable flexible sheeting on the soil surface reduces the amount of air that is being pulled into the heater well from the atmosphere. A thermal insulator covers the soil surface and reduces heat losses from the soil surface. The heater wells are connected to a vacuum manifold for collection of vapors. A heat front moves away from the heater wells through the soil by thermal conduction, and the superposition of heat from a plurality of heater wells results in a more uniform temperature rise throughout the well pattern. Soil contaminants are removed by vaporization, in situ thermal decomposition, oxidation, combustion, and by steam distillation. Both the presence of water vapor and the low pressure results in vaporization of the contaminants at temperatures well below their normal boiling points. Moreover, the heater wells and the nearby soil are extremely hot and most contaminants drawn into the wells will decompose with a residence time of the order of seconds. The heater well can also be packed with a catalyst that accelerates high temperature decomposition into simpler molecules. Water vapor and remaining contaminants may be incinerated in line or may be collected in a cold trap upstream from the vacuum pump.

An improved process for the remediation of soil contaminated by the presence therein of organic or semi-volatile inorganic contaminants which comprises (1) supplying thermal energy to the soil at one or more locations under the surface of the soil, (2) collecting the vapors resulting from contaminant vaporization or decomposition under the influence of the thermal energy, after passage horizontally through the soil, at one or more locations under the surface of the soil and separating from the collected vapors the environmentally undesirable components thereof.

Moist, warm, clean air from a vapor treatment system is injected into wells which are screened only at the contaminated depth forcing vapor flow only through the contaminated region. Intermediate the injection wells is an extraction well which is also screened only at the contaminated depth. A vacuum is drawn on the extraction well drawing the flushing vapors from the injection wells and toward the extraction well through the contaminated soil thereby entraining some of the contaminants. The contaminants are preferably non-volatile hydrocarbons such as diesel fuel, aviation and jet fuel, crude oil or pesticides. The contaminated, flushing vapor is then treated and recycled. An MW/RF heating system heats the earth's surface and the contaminated soil, thereby enhancing volatilization of the contaminants and their removal via the vapor flushing system. By screening the wells only through the contaminated zone and controlling the flow of clean, moist, warm air through only the contaminated zone, thereby maintaining the contaminated zone in a moist state, the entire energy of the system is focussed on the contaminated region.

In situ decontamination of spills and landfills by focussed

A process is disclosed for reducing the level of sulfides in aqueous solutiuons which comprises contacting a sulfide-containing solution having a pH value in the range from about 8.5 to 12 with oxygen in the presence of a flocculent manganese-containing catalyst having been prepared by aerating an aqueous solution of a divalent manganese salt, said salt solution having a pH value in the range from about 8.5 to about 12.

Process for sorption and catalytic oxidation of sulfides in water

A method and apparatus for reducing the concentration of haloorganic compounds in water-contaminated with haloorganic compounds is disclosed. The haloorganic compounds are extracted from the water and concentrated into certain water immiscible alkane hydrocarbon solvent. The solvent is separated from the water, is regenerated by ultraviolet radiation to degrade the haloorganics, and is recirculated to contact additional contaminated water. After extraction the water separated from the solvent may be subjected to conventional drinking water treatment, or passed to groundwater.

Process for reducing the concentration of haloorganic compounds in water

An improved process for the removal of H.sub.2 S from sour gas streams in which the H.sub.2 S is converted to sulfur by a polyvalent metal chelate solution is disclosed, the process being characterized by the washing of the product sulfur with an aqueous wash solution, and recovery of the acid precursor of the chelating agent from the washing solution.

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Houston, TX, United States of America

Charles C Chou