A method of recovering gaseous hydrocarbons from tank headspace includes flowing a hydrocarbon gas composition from headspace of a tank fed by a secondary separator into a compressor to form a compressed mixture. The method includes flowing the compressed mixture into a cooling unit to cool the compressed mixture, to form a cooled composition including liquid hydrocarbons. The method includes recovering the liquid hydrocarbons as a recovered liquid hydrocarbon stream.

Process and plant for recovering LPG in a refinery process combining the use of sponge absorber, deethanizer and debutanizer. The process and plant enable high LPG recovery and removal of hydrogen sulphide in the LPG product to low levels.

Provided is a continuous process for converting waste plastic into recycle for polypropylene polymerization. The process comprises selecting waste plastics containing polyethylene and/or polypropylene, and passing the waste plastics through a pyrolysis reactor to thermally crack at least a portion of the polyolefin waste and produce a pyrolyzed effluent. The pyrolyzed effluent is separated into offgas, a naphtha/diesel fraction, a heavy fraction, and char. Pyrolysis oil and wax, comprising naphtha/diesel and heavy fractions, is passed to a refinery FCC unit. A liquid petroleum gas C.sub.3 olefin/paraffin mixture is recovered from the FCC unit. The C.sub.3 paraffins and C.sub.3 olefins are separated into different fractions with the C.sub.3 olefin fraction passed to a propylene polymerization reactor, and the C.sub.3 paraffin fraction passed optionally to a dehydrogenation unit to produce additional propylene.

A treatment process for remediating H.sub.2S and other contaminants in liquids includes: partially filling a closed vessel with a contaminated liquid containing ≥5 ppm H.sub.2S with a head space above the liquid within the vessel where gasses released from the liquid from the liquid collect; separately providing a treatment composition in the head space so that the gasses from the liquid may contact the treatment composition; and permitting the contact between the vapors from the liquid and the treatment composition to continue until a collective concentration of H.sub.2S in the liquid and in the head space is <5 ppm. The treatment composition includes an aqueous solution containing at least one hydroxide compound, a collective concentration of the at least one hydroxide compound in the aqueous solution is in a range of 35-55 weight %, and the aqueous solution constitutes at least 80 weight % of the treatment composition.

A plastic catalytic pyrolysis process that can produce high yields of ethylene, propylene and other light olefins from waste plastics is disclosed. The catalytic product stream is quenched to below catalytic pyrolysis temperature quickly after exiting the reactor or bulk separation from the catalyst. Quench preserves selectivity of light olefinic monomers. The catalytic pyrolysis process can be operated in a single stage or a two-stage process.

A continuous process for converting waste plastic into recycle for polypropylene polymerization is provided. The process integrates refinery operations to provide an effective and efficient recycle process. The process comprises selecting waste plastics containing polyethylene and polypropylene and then passing the waste plastics through a pyrolysis reactor to thermally crack at least a portion of the polyolefin waste and produce a pyrolyzed effluent. The pyrolyzed effluent is separated into offgas, a naphtha/diesel fraction, a heavy fraction, and char. The naphtha/diesel fraction is passed to a refinery FCC unit, from which is recovered a liquid petroleum gas C.sub.3 olefin/paraffin mixture. The C.sub.3 paraffins and C.sub.3 olefins are separated into different fractions with a propane/propylene splitter. The C.sub.3 olefin fraction is passed to a propylene polymerization reactor. The C.sub.3 paraffin fraction is optionally passed to a dehydrogenation unit to produce additional propylene and then the resulting C.sub.3 olefin is passed to a propylene polymerization reactor. The heavy fraction of pyrolyzed oil is passed to an isomerization dewaxing unit to produce a lubricating base oil.

Pathways are disclosed for the production of liquefied petroleum gas (LPG) products comprising propane and/or butane, and in certain cases renewable products having non-petroleum derived carbon. In particular, a gaseous feed mixture comprising CO.sub.2 in combination with CH.sub.4 and/or H.sub.2 is converted by reforming and/or reverse water-gas shift (RWGS) reactions, further in combination with LPG synthesis. A preferred gaseous feed mixture comprises biogas or otherwise a mixture of CO.sub.2 and H.sub.2 that is not readily upgraded using conventional processes. Catalysts described herein have a high activity for reforming (including dry reforming) of CH.sub.4, as well as simultaneously catalyzing RWGS. These attributes improve the management of CO.sub.2 that is input to the disclosed processes, particularly in those utilizing recycle operation to increase overall CO.sub.2 conversion. Economics of small scale operations may be improved, if necessary, using an electrically heated reforming reactor in the first or initial reforming stage or RWGS stage.

Favorable isomerization conditions for producing normal paraffins can produce olefins. The process for separating normal paraffins from non-normal paraffins by adsorption has a limit on olefin concentration, so the olefins must be removed. We propose to remove olefins from the isomerization effluent stream that is recycled to the adsorption separation process.

Methods and systems are provided for the conversion of waste plastics into various useful downstream recycle-content products. More particularly, the present system and method involves integrating a pyrolysis facility with a cracker facility by introducing at least a stream of r-pyrolysis gas into the cracker facility. In the cracker facility, the r-pyrolysis gas may be separated to form one or more recycle content products, and can enhance the operation of the facility.

This disclosure relates to the production of chemicals and plastics using pyrolysis oil from the pyrolysis of plastic waste as a co-feedstock along with a petroleum-based or fossil fuel co-feed, or as a feedstock in the absence of a petroleum-based or fossil fuel co-feed. A mass balance accounting approach is employed to attribute the pounds of pyrolyzed plastic products derived from pyrolysis oil to any output stream of a given unit, which permits assigning circular product credit to product streams. In an aspect, the polymers and chemicals produced according to this disclosure can be certified under International Sustainability and Carbon Certification (ISCC) provisions as circular polymers and chemicals at any point along complex chemical reaction pathways.