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Topic: Steam cracking

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Cracking (chemistry)

Cumene process

Alkane

Hydrous pyrolysis

Ethylene

Pyrolysis

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Methane

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	Cracking (chemistry) - Wikipedia, the free encyclopedia
		The "spent" catalyst is disengaged from the cracked hydrocarbon vapors and sent to a stripper where it is contacted with steam to remove hydrocarbons remaining in the catalyst pores.
		Steam cracking is a petrochemical process in which saturated hydrocarbons are broken down into smaller, often unsaturated, hydrocarbons.
		The catalytic cracking process involves the presence of acid catalysts (usually solid acids such as silica-alumina and zeolites) which promote a heterolytic (asymmetric) breakage of bonds yielding pairs of ions of opposite charges, usually a carbocation and the very unstable hydride anion.
	en.wikipedia.org /wiki/Cracking_(chemistry) (1554 words)

	Encyclopedia: Steam cracking (Site not responding. Last check: 2007-10-29)
		Cracking processes allow the production of "light" products (such as LPG and gasoline) from heavier crude oil distillation fractions (such as gas oils and distillation residues).
		Fluid Catalytic Cracking (FCC for short) produces a high yield of petrol and LPG, while thermal cracking is currently used to "upgrade" very heavy fractions ("upgrading", "visbreaking"), or to produce light fractions or distillates, burner fuel and/or petroleum coke.
		The Burton process is a thermal cracking process invented by William M. Burton; the oil industry first used it to produce gasoline in 1913.
	www.nationmaster.com /encyclopedia/Steam-cracking (3141 words)

	Therm Cracking
		The thermally cracked residue tar, which accumulates in the bottom of the fractionation tower, is vacuum-flashed in a stripper and the distillate recycled.
		Steam cracking is a petrochemical process sometimes used in refineries to produce olefinic raw materials (e.g., ethylene) from various feedstock for petrochemicals manufacture.
		Because thermal cracking is a closed process, the primary potential for fire is from leaks or releases of liquids, gases, or vapors reaching an ignition source such as a heater.
	www.setlaboratories.com /therm.htm (1052 words)

	[No title] (Site not responding. Last check: 2007-10-29)
		Steam cracking is not considered to be suitable for cracking feeds containing high concentrations of light olefins as it makes high levels of low value heavy by-products due to the more reactive nature of the olefin feeds.
		The catalyst comprises a first component comprising a cracking catalyst having high activity, and, a second component, as a separate and distinct entity, the second component comprising a calcium/magnesium-containing material in combination with a magnesium- containing material, wherein the calcium/magnesium-containing compound is active for metals trapping, especially vanadium trapping.
		In a further aspect of the present invention, a catalytic cracking process comprises contacting a paraffinic hydrocarbon feedstream with a catalyst comprising a dehydrogenatio/cracking catalyst under suitable catalytic dehydrogenation/cracking conditions to produce olefin, wherein the catalytic dehydrogenation/cracking is conducted in the substantial absence of added heat.
	www.wipo.int /cgi-pct/guest/getbykey5?KEY=03/82462.031009&ELEMENT_SET=DECL (9186 words)

	Method and installation for steam cracking hydrocarbons - Patent 5139650
		The method according to claim 9, wherein after indirect quenching of the effluents, the solid particles are separated from the steam cracking effluents in a cyclone, the pressure of the recovered particles is increased, and the particles are recycled through said outlet manifold.
		However, there exists a hydrocarbon steam cracking method in which the reaction temperatures in the furnace and the temperatures of the effluents at the outlet from the furnace are very high (e.g.
		In general, the invention enables hydrocarbons to be steam cracked in a single-pass furnace having small-diameter tubes which are connected by means of an outlet manifold to a quenching heat exchanger, thereby obtaining a higher yield of olefins, but without running the risk of over cracking the effluents.
	www.freepatentsonline.com /5139650.html (3939 words)

	Process for controlling hydrocarbon steam cracking system using a spectrophotometer - Patent 5082985
		It is known to perform hydrocarbon cracking or pyrolysis in the presence of steam, also known as steam-cracking, by passing a mixture of hydrocarbons and steam through a cracking tube arranged in a furnace heated to a high temperature.
		C., the pressure in the cracking tube at the exit of this zone is from 120 kPa to 240 kPa, and the weight ratio of the quantity of the hydrocarbon mixture employed to that of steam is approximately from 1 to 6.
		The cracking temperature T at the exit of the radiation zone of the furnace and the naphtha feed flow rate Q to the tube can vary during this manufacture and are determined so that the output rates of ethylene and of propylene are constantly equal to 0.640 t/h and 0.370 t/h respectively.
	www.freepatentsonline.com /5082985.html (4187 words)

	Steam-cracking in a fluid bed reaction zone - Patent 5039395
		The steam cracking furnaces were improved essentially for reducing the residence time and the pressure drop, by decreasing the length of the tubular reactors, thus increasing the thermal flow, particularly near the reactor feeding port.
		4,370,303 which discloses a steam cracking process where the charge is cracked in the presence of steam by contact with hot solid particles in a first portion of a reaction zone, the obtained effluent is then separated from the hot particles in a primary separation zone and then in a separation zone of cyclone type.
		Steam used for desorbing the hydrocarbons fixed onto the particles is supplied through line 23 to the lower part 7b of the enclosure.
	freepatentsonline.com /5039395.html (5982 words)

	Combination process for manufacturing ethylene, benzene and alkylated benzene - US Patent 6177600 (Site not responding. Last check: 2007-10-29)
		This hydrocarbon steam mixture is further preheated in heater 18 and proceeds, line 20 prior to the cracking section of the pyrolysis furnace 22.
		The steam at 110-130 psig is ultimately used as a dilution steam for the naphtha and recycle feeds 16.
		However, the conversion by thermal steam cracking in the furnace with co-production of ethylene is an element of the invention.
	www.patentstorm.us /patents/6177600.html (4071 words)

	The Hendrix Group - petroleum refining corrosion
		Steam is often used in towers to lower the vapor pressure and create a partial vacuum.
		This cracking continues until the oil vapors are separated from the catalyst in the reactor cyclones.
		The regenerator and hopper are isolated from the reactor by steam seals.
	www.hghouston.com /refining.html (8939 words)

	[No title] (Site not responding. Last check: 2007-10-29)
		The cracked products are discharged from the riser to pass through a main column, which produces several liquid streams and a vapor stream containing hydrogen, methane, ethane, propane, butane, and light olefins.
		The second category of catalytic cracking is catalytic cracking of naphtha, the main purpose of which is the generation of light olefins.
		FCC of gas oil, and catalytic cracking of olefinic naphtha, hydrogen is undesirable due to the difficulty of separating H2 from the light olefins (ethylene and propylene).
	www.wipo.int /cgi-pct/guest/getbykey5?KEY=04/71656.040826&ELEMENT_SET=DECL (8667 words)

	PWR Steam Generator Feedwater Nozzle Cracking Evaluation/Repair (Site not responding. Last check: 2007-10-29)
		Cracking in steam generator feedwater (FW) nozzles and adjacent piping has been a major problem in the pressurized water reactor (PWR) industry since the first incidence was discovered in the late 1970's.
		Cracking has been typically remedied by replacing the FW piping adjacent to the nozzle with a new, but essentially identical, transition piece.
		The weld preparation counterbore at the steam generator nozzle-to-piping weld generally involves a significant thickness change from the thinner nozzle to the thicker piping due to strength differences between the nozzle and piping materials.
	structint.com /tekbrefs/sib96152 (1039 words)

	Catalyst for steam cracking reactions and related preparation process - US Patent 6696614 (Site not responding. Last check: 2007-10-29)
		Steam cracking is a thermal process which is carried out on an industrial scale without catalysts.
		The idea is based on coating the inside of the cracking tubes with a solid layer having a catalytic effect and which inhibits the formation of coke, thus prolonging the times between subsequent stoppages for decoking operations.
		Steam cracking reaction effected in a laboratory plant in continuous with a fixed bed reactor having a diameter of 1/2".
	www.patentstorm.us /patents/6696614.html (2258 words)

	[No title] (Site not responding. Last check: 2007-10-29)
		Ethylene is typically obtained from the non-catalytic thermal cracking of saturated hydrocarbons such as ethane and propane and alternatively from the thermal or steam cracking of heavier liquids such as naphtha and gas oil.
		An alternative is to catalytically crack paraffinic hydrocarbon in the presence of oxygen to form mono-olefins, that is, autothermal partial oxidation of paraffinic hydrocarbons to olefins.
		By employing a fluid-bed reactor there is a noticeable difference in the capital investment due to the elimination of the large, expensive and complex furnaces used in conventional steam cracking processes.
	www.chemsystems.com /newsletters/perp/Jul04_N03S2.cfm (1783 words)

	Information Notice No. 81-04: Cracking in Main Steam Lines (Site not responding. Last check: 2007-10-29)
		Cracking was also observed in the weld counterbore at the opposite end of the T-fitting during visual examination of the piping interior.
		Metallurgical specimens of the cracking were trepanned from the T-fitting of the "A" main steam line for analysis.
		For those plants having similar main steam line configurations which are currently in a refueling or extended repair outage, it is recommended that a ultrasonic and/or radiographic examination of the three welds and counterbore areas of the T-fittings be performed before resumption of operations, unless some current basis for assurance of piping integrity is available.
	www.nrc.gov /reading-rm/doc-collections/gen-comm/info-notices/1981/in81004.html (344 words)

	Method for producing refractories - Patent 4229221 (Site not responding. Last check: 2007-10-29)
		obtained by thermal cracking or steam cracking of petroleum hydrocarbons in a first state stirring vessel maintained at a pressure of higher than 2 Kg/cm.sup.2 G and a temperature within the range of from 300.degree.
		obtained by thermal cracking or steam cracking of petroleum hydrocarbons as a raw material oil in a first stage stirring vessel maintained at a pressure of more than 2 Kg/cm.sup.2 G and at a temperature in the range of from 300.degree.
		obtained by thermal cracking or steam cracking of petroleum hydrocarbon in a first stage stirring vessel maintained at a pressure of higher than 2 Kg/cm.sup.2 G and a temperature within the range of from 300.degree.
	www.freepatentsonline.com /4229221.html (6729 words)

	Process Economics Report 248: Steam Cracking For Olefins Production
		The technology for producing olefins by thermal steam cracking appears to have reached a stage of maturity in which improvements in yield and product selectivity are becoming increasingly difficult.
		For the conventional steam cracking process, ethylene yields are improved by raising the cracking temperature and reducing residence time, i.e., increasing the cracking severity.
		An alternative route to improving the performance of steam cracking is to carry out the reaction in the presence of a catalyst.
	www.sric.sri.com /PEP/Reports/Phase_2003/RP248/RP248.html (358 words)

	Benzene - Encyclopedia, History, Geography and Biography
		In catalytic reforming, a mixture of hydrocarbons with boiling points between 60-200°C is blended with hydrogen gas, then exposed to a platinum chloride or rhenium chloride catalyst at 500-525°C and pressures ranging from 8-50 atm.
		Sometimes, xylene and heavier aromatics are used in place of toluene, with similar efficiency.
		Steam cracking is the process used to produce ethylene and other olefins from aliphatic hydrocarbons.
	www.arikah.com /encyclopedia/Benzene (1788 words)

	HTML-txt: OPERATING EXPERIENCE WITH THERMALLY TREATED ALLOY 600 TUBES IN MODEL F STEAM GENERATORS : CRACKING
		Steam generator tube in nuclear power plant is a boundary between primary side and secondary side, whose integrity is one of the most critical factors to nuclear safety.
		The first one was OD circumferential crack at the hotleg top of tubesheet found in the tube R14 C61 of steam generator 'C' in 1995.
		The second one was also OD circumferential crack found in the tube R52 C88 of steam generator 'B', but the location was at the coldleg top of tubesheet in 1999.
	www.ndt.net /article/wcndt2004/html/htmltxt/207_kim.htm (2348 words)

	Steam Dryer Crack Evaluation
		Steam dryer component cracking has recently been of significant interest in BWR plants operating at extended power uprate (EPU).
		The results of finite element modeling performed prior to EPU operation were not consistent with the extent of observed cracking.
		Structural Integrity has contributed in third party review of various analyses including finite element structural, acoustic modeling to help define the forcing function and performed finite element analyses to better understand the complicated stress state at various key locations.
	www.structint.com /tekbrefs/datasheets/steamdryer/index.html (254 words)

	[No title]
		Majority of the ethylene produced today is based on the steam cracking or pyrolysis of alkanes, such as ethane, propane and butane, as well as heavier feedstocks such as naphtha and gas oil (Lee and Aitani, 1990).
		The steam cracking of a feedstock is accomplished in the coils of a pyrolysis furnace followed by quenching of the gas in a heat exchanger (Matar and Hatch, 1994) or the transfer line exchanger.
		In Figure 1 the experimental apparatus used to study the formation of coke during the steam cracking of ethane and propane is illustrated.
	www.seas.ucla.edu /~senkan/cokesupp.html (4929 words)

	EPRI: BWRVIP-139: Vessel and Internals Project, Steam Dryer Inspection and Flaw Evaluation Guidelines (Site not responding. Last check: 2007-10-29)
		The purpose of this document is to define baseline visual inspection requirements for BWR steam dryer assemblies, current steam dryer configurations, areas of known fatigue cracking and IGSCC susceptibility, locations of relatively high stress, flaw evaluation methods to be used if cracking is discovered, steam line moisture carryover measurement techniques, and limited flaw repair guidance.
		The team developed a preliminary limiting steam dryer load definition based on data from previous start-up testing at one BWR and applied this load time history to a finite element model of the steam dryer to assess relative stress magnitudes spatially over the dryer assembly.
		Recommended inspection locations are based on review of results of previous steam dryer inspections and structural analyses to determine the relative magnitude of stresses at various locations on the dryer assembly.
	www.epri.com /OrderableitemDesc.asp?product_id=000000000001011463&searchdate=04/01/2005 (489 words)

	Steam System Cracking - Corrosionsource.com Discussion Boards
		The non-branched nature of cracking is typical of the situation of SCC with high residual stresses in non-PWHT welds.
		To confirm caustic SCC you may be able to measure pH in cracks taken from failed equipment which would be an indication of concentration of caustic.
		One has been transverse cracks in a Stopple flange weld and another in the HAZ of the downstream orifice flange to pipe weld.
	www.corrosionsource.com /discuss2/ubb/Forum2/HTML/000172.html (482 words)

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