63 results about "Coke deposition" patented technology

The average propylene cycle yield of an oxygenate to propylene (OTP) process using a dual-function oxygenate conversion catalyst is substantially enhanced by the use of a combination of: 1) moving bed reactor technology in the catalytic OTP reaction step in lieu of the fixed bed technology of the prior art; 2) a separate heavy olefin interconversion step using moving bed technology and operating at an inlet temperature at least 15° C. higher than the maximum temperature utilized in the OTP reaction step; 3) C₂ olefin recycle to the OTP reaction step; and 4) a catalyst on-stream cycle time of 700 hours or less. These provisions hold the build-up of coke deposits on the catalyst to a level which does not substantially degrade dual-function catalyst activity, oxygenate conversion and propylene selectivity, thereby enabling maintenance of average propylene cycle yield for each cycle near or at essentially start-of-cycle levels.

The invention provides a catalyst for preparing olefin from low-carbon alkane by dehydrogenation. The catalyst comprises an aluminum oxide carrier and the following active components with the carrier as datum by mass: 0.1 to 2.0% of a group-VIII metal, 0.1 to 2.0% of a second metal component, 0.5 to 5.0% of a group-IA metal and 0.3 to 10.0% of halogen, wherein the aluminum oxide carrier has a pore volume of pores with a diameter of 2 to 10 nanometers accounting for 4 to 15% of a total pore volume, a pore volume of pores with a diameter of 10 to 20 nanometers accounting for 40 to 60% of the total pore volume, a pore volume of pores with a diameter of 20 to 50 nanometers accounting for 1.0 to 5.0% of the total pore volume, and a pore volume of pores with a diameter of more than 50 nanometers and less than 10 microns accounting for 20 to 50% of the total pore volume; and the second metal component is selected from the group consisting of tin, germanium, lead, indium, gallium or thallium. The catalyst is applied to preparation of propylene from propane by dehydrogenation and has high activity and selectivity and low coke deposition rate.

The present invention is related to the preparation of a metal lattice-doping catalyst in an amorphous molten state, and the process of catalyzing methane to make olefins, aromatics, and hydrogen using the catalyst under oxygen-free, continuous flowing conditions. Such a process has little coke deposition and realizes atom-economic conversion. Under the conditions encountered in a fixed bed reactor (i.e. reaction temperature: 750˜1200° C.; reaction pressure: atmospheric pressure; the weight hourly space velocity of feed gas: 1000˜30000 ml/g/h; and fixed bed), conversion of methane is 8-50%. The selectivity of olefins is 30˜90%. And selectivity of aromatics is 10˜70%. There is no coking. The reaction process has many advantages, including a long catalyst life (>100 hrs), high stability of redox and hydrothermal properties under high temperature, high selectivity towards target products, zero coke deposition, easy separation of products, good reproducibility, safe and reliable operation, etc., all of which are very desirable for industrial application.

The present invention provides a system and a method to reform hydrocarbon fuels, including sulfur-laden liquid fuels, to produce a reformate stream containing hydrogen. The system comprises a reforming reactor using a hydrocarbon stream and a water stream as reactants. The water stream is mixed with a hydrogen-rich stream prior to mixing with the hydrocarbon stream and fed to the reforming reactor, which contains a precious metal based catalyst. In one embodiment of the present invention, the temperature of the catalyst is lower at the inlet to prevent formation of coke by pre-reforming heavy hydrocarbons to methane, and higher at the outlet for efficient production of hydrogen. In another embodiment, air is introduced periodically into the system to burn off any metal sulfides and coke deposits that could form. In another embodiment, pure hydrogen is separated from the reformate stream using a hydrogen selective, sulfur-tolerant membrane or by pressure swing adsorption. Thus, the system and method of the present invention can be used to process sulfur-laden, heavy hydrocarbons to produce PEM fuel-cell quality hydrogen.

The invention relates to an efficient scale inhibitor of a tail-gas compressor of a styrene device and an application method thereof, comprising hydroxylamine compounds, alcohol amine compounds and phenol compounds. The invention overcomes the disadvantages that the generation of polymer dirt in the tail-gas compressor can not be effectively inhibited by using an ethylbenzene physical spraying method, can thoroughly inhibit and suppress the radical polymerization of the styrene, alpha-methyl styrene, phenyl ethylene and the other activated alkenes in the styrene tail-gas compressor, and has the functions of metallic catalytic coke deposition suppression and detergency and dispersancy. The invention has the advantages of safety and environment protection, energy conservation and low energy consumption and simple use, has no influence on downstream processes, can effectively promote the operational cycle and working load of the styrene tail-gas compressor, reduce energy and material consumption of the styrene device, and can improve the economical and social effects of the whole styrene device.

The invention relates to an anti-coking anti-carburizing cracking furnace tube and a manufacturing method thereof. The inner surface of the cracking furnace tube of the invention has a layer which comprises an oxide membrane which comprises at least one of Cr, Ni, Fe, Mn, La, Ce and Y. The manufacturing method comprises the following steps: Ni-Cr alloy containing elements of Cr, Ni, Fe, Mn and C is directly added to at least one element selected from La, Ce or Y in a routine cracking furnace tube manufacturing process to prepare a tube; and the tube is subjected to heat treatment in low oxygen partial pressure atmosphere to generate a layer of the metal oxide membrane on the inner surface. The coke deposition on the inner surface of the radiant section furnace tube can be reduced by more than 60% when the cracking furnace tube of the invention is used in a petroleum hydrocarbon cracking furnace to produce low carbon number olefins.

A process of methane catalytic conversion produces olefins, aromatics, and hydrogen under oxygen-free, continuous flowing conditions. Such a process has little coke deposition and realizes atom-economic conversion. Under the conditions encountered in a fixed bed reactor (i.e. reaction temperature: 750-1200° C.; reaction pressure: atmospheric pressure; the weight hourly space velocity of feed gas: 1000-30000 ml/g/h; and fixed bed), conversion of methane is 8-50%. The selectivity of olefins is 30-90%. And selectivity of aromatics is 10-70%. The catalyst for this methane conversion has a SiO₂-based matrix having active species that are formed by confining dopant metal atoms in the lattice of the matrix.

The present invention relates to a catalyst for steam pre-reforming of hydrocarbons, containing in its formulation nickel and rare earths supported on alumina or magnesium or calcium aluminates, so as to increase the resistance to coke deposition, and the process for preparing said catalyst. Additionally the present invention relates to a process for manufacturing hydrogen or syn gas through steam pre-reforming olefin-containing hydrocarbons in the presence of the catalyst obtained according to the present invention.

A coke removal system removes coke deposits from the walls of a high temperature passage in which hydrocarbon fuel is present. The system includes a carbon-steam gasification catalyst and a water source. The carbon-steam gasification catalyst is applied to the walls of the high temperature passage. The water reacts with the coke deposits on the walls of the high temperature passage to remove the coke deposits from the walls of the high temperature passage by carbon-steam gasification in the presence of the carbon-steam gasification catalyst.

This invention relates to a process for reactivating a dehydrocyclodimerization catalyst. Dehydrocyclodimerization catalysts which contain an aluminum phosphate binder can be deactivated when they are exposed to hydrogen at temperatures above 500° C. The instant process restores substantially all of the catalyst's lost activity. The process involves treating the catalyst with a fluid comprising water and drying the catalyst. The process is employed particularly advantageously in combination with coke removal for reactivating catalysts that contain coke deposits and that have also been hydrogen deactivated. This invention also relates to a method of producing a dehydrocyclodimerization catalyst that is resistant to hydrogen deactivation.

The invention discloses a naphtha hydrogenation method and a decoking tank. The naphtha hydrogenation method comprises the following steps of heating a mixture of a naphtha feedstock and hydrogen in a heating surface to a temperature required by hydrofining, then carrying out decoking by the decoking tank, and then feeding the decoked mixture into a fixed bed hydrogenation reactor. The decoking tank comprises a cylindrical body, an upper head, a lower head and a separator. The separator comprises a box plate and multiple separation pipe assemblies fixed to the box plate. The decoking tank is divided into two parts by the box plate, wherein one part is a channel for outflow of filtered materials and the other part is a coke deposition zone. Compared with the prior art, the naphtha hydrogenation method and the decoking tank can effectively and economically prolong a naphtha hydrogenation device running period.

Some embodiments of the present invention provide components for a serpentine fluid reactor which is optimized for one or more objective functions of interest such as pressure drop, erosion rate, fouling, coke deposition and operating costs. The components are designed by computer modeling the components individually and collectively in which the cross section of flow path is substantially circular under industrial conditions to validate the model design and its operation. Then iteratively the component designs are deformed and the operation of the deformed part(s) is modeled and compared to values obtained with other deformed models until the value of the objective function is optimized (e.g. at an extreme) or the change in the objective function is approaching zero.

The invention discloses a method for detecting coke deposition of a catalyst by utilizing nuclear magnetic resonance. The method comprises the following steps of acquiring a carbon nuclear magnetic resonance spectrum of samples of certain quantity with known coke deposition, correlating and modeling a carbon spectrum peak area set and a coke deposition set of the known samples after being pretreated, and calculating the coke deposition of an unknown sample by predicting the carbon nuclear magnetic resonance spectrum of the model and the unknown sample. The method is fast, accurate and stable, can be used for offline detecting the coke deposition on a solid acid catalyst in the industry and is significant for optimizing a catalyst reaction-renewable system.

The present disclosure addresses the deficiencies described above by providing systems and methods for enhancing the efficiency and yield of alkene production. The methods and systems provide for the use of activated CO₂ in a dehydrogenation reactor along with an alkane stream. Through the use of the methods and systems of the invention, catalyst deactivation by coke deposition is reduced and the selectivity and efficiency of the dehydrogenation reaction is improved.

A steam-assisted catalytic cracking process for a hydrocarbon feed is provided. The process includes: introducing the hydrocarbon feed, a fluid catalytic cracking (FCC) catalyst, and steam to a FCC reactor with a mass ratio of steam to hydrocarbon feed between 0.05 and 1.0; cracking the hydrocarbon feed in the presence of the FCC catalyst and steam to produce a cracked hydrocarbon feed and spent FCC catalyst, the spent FCC catalyst comprising coke deposits and hydrocarbon deposits; stripping the hydrocarbon deposits from the spent FCC catalyst with steam in a stripper to obtain a hydrocarbon-stripped spent FCC catalyst; regenerating the hydrocarbon-stripped spent FCC catalyst in a regenerator by subjecting the stripped spent FCC catalyst to heat in the presence of oxygen to combust the coke deposits on the stripped spent FCC catalyst and produce a regenerated FCC catalyst; recycling the regenerated FCC catalyst.