The present invention relates to internally profiled variable pitch tubes or pipes made of steel. The terms tube and pipe are used synonymously in the context of this invention. These tubes are used in the petrochemical industry to crack oil, gas and shale feedstocks into simple hydrocarbons such as ethylene and similar products.

Processes and systems for making recycle content hydrocarbons, including olefins, using a cracker furnace having enhanced coil design. In some cases, the design of the furnace may prevent coking, so that the run length of the furnace is longer than conventional cracking furnaces. Cracker feed streams to the furnace can include recycle content pyrolysis oil and may be used to form olefin-containing effluent stream having recycle content.

A system and a method for steam cracking hydrocarbons are disclosed. The system includes a steam cracking furnace that includes ceramic radiant coils. The system is configured to heat the radiant coils by oxy-fuel combustion in the firebox. The system further includes an oxygen production unit configured to produce pure oxygen used for the oxy-fuel combustion. The effluent from the steam cracking furnace can be further separated into various product streams or fed into a polymerization unit.

In one aspect, the present invention relates to a furnace having a heated portion arranged adjacent to an unheated portion. A plurality of straight tubes are formed of a first material and are at least partially disposed in the heated portion. A plurality of return bends are operatively coupled to the plurality of straight tubes. The plurality of return bends are formed of a second material and are at least partially disposed in the unheated portion. The first material exhibits a maximum temperature greater than the second material thereby facilitating increased run time of the furnace. The second material exhibits wear-resistance properties greater than the first material thereby facilitating wear-resistance of the furnace.

The present invention provides a pyrolysis tube for manufacturing olefin which tube can improve a yield of olefin in a pyrolysis reaction of a hydrocarbon raw material. The pyrolysis tube (1A) for manufacturing olefin includes a tubular base material (2) made of a heat resistant metal material and a dehydrogenating catalyst (4A) which is supported on an inner surface of the tubular base material (2).

Described herein is a gaslight multilayered composite tube having a heat transfer coefficient of >500 W/m.sup.2/K which in its construction over the cross section of the wall of the composite tube includes as an inner layer a nonporous monolithic oxide ceramic surrounded by an outer layer of oxidic fiber composite ceramic, where this outer layer has an open porosity of 5%<ε<50%, and which on the inner surface of the composite tube includes a plurality of depressions oriented towards the outer wall of the composite tube. Also described herein is a method of using the multilayered composite tube as a reaction tube for endothermic reactions, jet tubes, flame tubes or rotary tubes.

An anti-coking surface having a thickness up to 15 microns comprising from 15 to 50 wt. % of MnCr.sub.2O.sub.4 (for example manganochromite); from 15 to 25 wt. % of Cr.sub.0.23Mn.sub.0.08Ni.sub.0.69 (for example chromium manganese nickel); from 10 to 30 wt. % of Cr.sub.1.3Fe.sub.0.7O.sub.3 (for example chromium iron oxide); from 12 to 20 wt. % of Cr.sub.2O.sub.3 (for example eskolaite); from 4 to 20 wt. % of CuFe.sub.5O.sub.8 (for example copper iron oxide); and less than 5 wt. % of one or more compounds chosen from FeO(OH), CrO(OH), CrMn, Si and SiO.sub.2 (either as silicon oxide or quartz) and less than 0.5 wt. % of aluminum in any form provided that the sum of the components is 100 wt. % is provided on steel.

An anti-coking surface having a thickness up to 15 microns comprising from 15 to 50 wt. % of MnCr.sub.2O.sub.4 (for example manganochromite); from 15 to 25 wt. % of Cr.sub.0.23Mn.sub.0.08Ni.sub.0.69 (for example chromium manganese nickel); from 10 to 30 wt. % of Cr.sub.1.3Fe.sub.0.7O.sub.3 (for example chromium iron oxide); from 12 to 20 wt. % of Cr.sub.2O.sub.3 (for example eskolaite); from 4 to 20 wt. % of CuFe.sub.5O.sub.8 (for example copper iron oxide); and less than 5 wt. % of one or more compounds chosen from FeO(OH), CrO(OH), CrMn, Si and SiO.sub.2 (either as silicon oxide or quartz) and less than 0.5 wt. % of aluminum in any form provided that the sum of the components is 100 wt. % is provided on steel.

Reactor components formed using an erosion resistant alloy having desirable high temperature mechanical strength are provided. The erosion resistant components can include, but are not limited to, tubes, re-actors walls, fittings, and/or other components having surfaces that can be exposed to a high temperature reaction environment in the presence of hydrocarbons and/or that can provide pressure containment functionality in processes for upgrading hydrocarbons in a high temperature reaction environment. The erosion resistant alloy used for forming the erosion resistant component can include 42.0 to 46.0 wt. % nickel; 32.1 to 35.2 wt. % um; 0.5 to 2.9 wt. % carbon; 0 to 2.0 wt. % titanium; 0 to 4.0 wt. % tungsten, and iron, with at least one of titanium and tungsten is present in an amount of 1.0 wt. % or more. The iron can correspond to the balance of the composition. Optionally, the erosion resistant alloy can provide further improved properties based on the presence of at least one strengthening mechanism within the alloy, such as a carbide strengthening mechanism, a solid solution strengthening mechanism, a gamma prime strengthening mechanism, or a combination thereof.

An anti-coking equipment, a preparation method therefor, and the use thereof. The preparation method comprises: bringing a low-oxygen partial pressure gas into contact with an equipment for reaction to obtain an anti-coking equipment containing an oxide film on the inner surface, wherein the dew point of the low-oxygen partial pressure gas is -40° C. to 40° C.

A dense and stable oxide film is formed on the inner surface of the equipment prepared by the method, which can inhibit or slow down the catalytic coking phenomenon, reduce the degree of equipment carburization, and prolong the service life of the equipment.