Tail gas treatment catalyst, preparation method therefor and use thereof

Disclosed in the present invention is a tail gas treatment catalyst. The catalyst consists of a carrier, a first catalyst, and a second catalyst. The first catalyst and the second catalyst are provided on both ends of the carrier. The first catalyst can purify pollutants in tail gas. The second catalyst can purify a byproduct, ammonia, obtained by the purification by the first catalyst and pollutants that are not completely purified by the first catalyst. The second catalyst is of a double-layer structure; the lower layer consists of an oxygen storage material, aluminum oxide, and a second active component; the second active component is a composition of Pt and Pd, or a composition of Ce, Fe, Ni and Cu; the upper layer consists of a molecular sieve and a third active component; the third active component is Cu or a composition of Cu and Fe. The tail gas treatment catalyst of the present invention has high purification treatment efficiency, and can significantly reduce the emissions of CH4, CO, and NOx in the tail gas, especially reduce the content of the byproduct, NH3, so that the tail gas can meet China VI emission standards.

INTEGRATED CATALYST SYSTEM FOR STOICHIOMETRIC-BURN NATURAL GAS VEHICLES AND PREPARATION METHOD THEREFOR

Disclosed in the present invention is an integrated catalyst system for stoichiometric-burn natural gas vehicles, the catalyst system consisting of a three-way catalyst, a molecular sieve catalyst, and a base body, the three-way catalyst and the molecular sieve catalyst being coated on a surface of the base body. In the integrated three-way catalyst and molecular sieve catalyst system of the present invention, at the same time that pollutants such as CO, HC, and NOin the exhaust of stoichiometric-burn natural gas vehicles are processed, the produced byproduct NHcan also be processed, and the conversion rates of CO, HC, NO, and NHare high. 1. An integrated catalyst system for a stoichiometric-burn natural gas vehicle , characterized in that , the catalyst system consists of a three way catalyst , a molecular sieve catalyst and a base body , wherein the three way catalyst and the molecular sieve catalyst are coated on a surface of the base body , whereinthe three way catalyst and the molecular sieve catalyst are combined in the following way:the molecular sieve catalyst is uniformly added into a coating layer of the three way catalyst; orthe molecular sieve catalyst is coated on a surface of the three way catalyst; orthe molecular sieve catalyst is coated between two layers of the three way catalyst; orthe three way catalyst and the molecular sieve catalyst are coated in segments, wherein the three way catalyst is coated on a former segment of the base body, and the molecular sieve catalyst is coated on a latter segment of the base body.2. The integrated catalyst system according to claim 1 , characterized in that claim 1 , a combined loading amount of the three way catalyst and the molecular sieve catalyst is 150 g/L-300 g/L claim 1 , whereina loading amount ratio of the three way catalyst to the molecular sieve catalyst is (1:3)-(3:1).3. The integrated catalyst system according to claim 1 , characterized in that claim 1 , for the three way catalyst claim 1 , a ...

Method for preparing molecular sieve SCR catalyst, and catalyst prepared therethrough

A method for preparing a molecular sieve SCR (selective catalytic reduction) catalyst and a prepared catalyst therethrough. In the method, several molecular sieves are mixed and modified by transition metal or rare-earth metal via ion exchange, then loaded Fe by equivalent-volume impregnation, and loaded Cu by one or more liquid ion exchange. This present invention, combined with several techniques, such as modification of stable molecular sieve by transition and rare-earth metal, Fe loading by equivalent-volume impregnation and Cu loading by one or more liquid ion exchange, and after through stable and effective modification and loading control, the obtained catalyst material is coated on a carrier substrate via size mixing and coating process to be prepared into an integral catalyst. 1. A method for preparing a molecular sieve SCR catalyst , wherein comprising the following steps of:(1) molecular sieve mixing: firstly adding deionized water to several molecular sieves for size mixing, and performing liquid spray drying, then granulating after uniformly mixing;(2) molecular sieve modification: dissolving soluble transition metal and/or rare-earth metal salt into deionized water, and heating up to 70-90° C., wherein concentration of the solution ranges within 0.01-0.5 mol/L, adding the powdered molecular sieve prepared in the step (1) under stirring condition, performing ion exchange in a 70-90° C. thermostatic reaction kettle for 2-12 h, filtering, washing and drying;(3) active component Fe loading by isometric equivalent-volume impregnation: weighing the powdered molecular sieve obtained in step (2) for further use, firstly testing saturated water absorption of the molecular sieve per unit mass, calculating the total water absorption, dissolving soluble Fe salt into deionized water, stirring and dissolving, wherein total volume of the solution is equal to total water absorption of the molecular sieve; adding the prepared powdered molecular sieve and stirring it on ...

Method and system for searching for resonant frequency of transducer

A system for searching for a resonant frequency of a transducer, comprising: an initializing unit ( 11 ), a phase determining unit ( 12 ), an interval hopping control unit ( 13 ), a hopping interval generating unit ( 15 ), a frequency output control unit ( 17 ), a phase acquiring unit ( 16 ), and a resonant frequency obtaining unit ( 14 ). The search range of the interval for the last search can be narrowed by at least half thereof in each frequency hopping, thus allowing for reduced amount of searches.

ULTRASONIC SURGICAL INSTRUMENT AND ULTRASONIC SURGICAL SYSTEM

Disclosed are an ultrasonic surgical instrument () and ultrasonic surgical system; the ultrasonic surgical instrument () includes a waveguide () rotatable around an axis and in threaded connection with a transducer (); a force transmission mechanism is in fixed connection with the waveguide (), which has at least one stress surface (); a rotatable mechanism includes a pushing mechanism and a rotatable driving mechanism having at least one force applying surface (), the applying surface () and the stress surface () are not perpendicular to the axis, and can be engaged with each other; the pushing mechanism provides a pushing force the rotatable driving mechanism towards the force transmission mechanism, and the rotatable driving mechanism can overcome the pushing force when interaction force between the applying surface () and the stress surface () is in excess of a predetermined value. 1. An ultrasonic surgical instrument , comprising a waveguide rotatable around an axis and in threaded connection with a transducer , wherein said ultrasonic surgical instrument further comprises a force transmission mechanism and a rotatable mechanism; said force transmission mechanism is in fixed connection with said waveguide , provided with at least one stress surface thereon; said rotatable mechanism comprises a pushing mechanism and a rotatable driving mechanism having at least one applying surface thereon; said stress surface and said applying surface are not perpendicular to said axis and can be engaged with each other; said pushing mechanism provides a pushing force to press said rotatable driving mechanism towards said force transmission mechanism so as to force said stress surface being engaged with said applying surface; said pushing force is configured such that when a force between said stress surface and said applying surface is in excess of a predetermined value , said rotatable driving mechanism can overcome said pushing force so as to make said stress surface ...

Ozone Purification Catalyst and Preparation Method and Application Thereof

An ozone purification catalyst, and a preparation method therefor and an application thereof are provided. The catalyst coating uses macroporous, high specific surface and CeOand/or LaOmodified AlOas the carrier material, and Mn and/or Pd as the active component. The preparation method is to prepare the AlO-based material by a sol-gel method, and then to load the active components on the carrier material, and to dry, calcinate and solidify to obtain the ozone purification catalyst. The catalysts as prepared shows a fast and efficient purification of ozone. The complete conversion temperature covers a wide range of temperature. The catalyst has excellent texture performance, high specific surface area and large pore volume, which is beneficial to ozone purification when the car is running at high speed. The particle sizes and colors of the catalyst can be modified according to various requirements. According to the actual application, it can be coated on the radiator fins of automobile water tanks, and any place where coating is allowed in public areas such as urban bus stations, stop signs, kiosks, roadside guardrails, or exterior walls of buildings that is in contact with outdoor air. 1. A preparation method of an ozone purification catalyst , characterized in that it comprises the following steps:{'sub': 2', '2', '3', '2', '3', '2', '2', '3', '2', '3, 'preparing CeOand/or LaOmodified AlOby a sol-gel method; mixing a soluble Ce salt solution or/and a soluble La salt solution with pseudo-boehmite, and adjusting the pH by acid to 3.5 to 4.5, wherein the CeOcontent accounts for 0 to 30 wt %, the LaOcontent accounts for 0 to 5 wt %, and the AlOcontent accounts for 65 to 100 wt %; then calcinating at 500 to 600° C. in air atmosphere for 2 to 5 hours, and then at 800° C. in air atmosphere for 2 to 5 hours to obtain a modified carrier;'}loading a soluble Pd salt solution and/or a soluble Mn salt solution the modified carrier obtained in the Step (1) by an equal-volume ...

Low-temperature NOx storage catalyst used for automobile exhaust purification and preparation method thereof

A low-temperature NOx storage catalyst for automobile exhaust purification and a preparation method thereof. Loading a noble metal salt solution on molecular sieve by equal volume impregnation method, wherein the noble metal salt solution comprises palladium nitrate and platinum nitrate, and the molecular sieve comprises SSZ, SAPO and BETA, then drying at 60-120° C. for 2-6 h, roasting at 500-550° C. in air for 2-5 h, and further roasting at 750-850° C. in air for 2-5 h, and then mixing with aluminum sol, ball milling and pulping, and then coating the slurry on a carrier, wherein the loading on the coating is 100-250 g/L and the noble metal content is 10-150 g/ft3, drying at 60-120° C. for 2-6 h, then roasting at 500-550° C. in air for 2-5 h, and further continuing roasting at 750-850° C. in air for 2-5 h, to obtain the catalyst. Loading the noble metals Pt and Pd into a pore channel of a molecular sieve improves NOx storage capacity of a catalyst at low temperatures, and selecting a different type of molecular sieve as an NOx storage unit and increasing a roasting temperature of a molecular sieve material on which Pt and Pd are loaded significantly increases NOx storage capacity.

LOW-TEMPERATURE NOx STORAGE CATALYST USED FOR AUTOMOBILE EXHAUST PURIFICATION AND PREPARATION METHOD THEREOF

A low-temperature NOx storage catalyst for automobile exhaust purification and a preparation method thereof. Loading a noble metal salt solution on molecular sieve by equal volume impregnation method, wherein the noble metal salt solution comprises palladium nitrate and platinum nitrate, and the molecular sieve comprises SSZ, SAPO and BETA, then drying at 60-120° C. for 2-6 h, roasting at 500-550° C. in air for 2-5 h, and further roasting at 750-850° C. in air for 2-5 h, and then mixing with aluminum sol, ball milling and pulping, and then coating the slurry on a carrier, wherein the loading on the coating is 100-250 g/L and the noble metal content is 10-150 g/ft3, drying at 60-120° C. for 2-6 h, then roasting at 500-550° C. in air for 2-5 h, and further continuing roasting at 750-850° C. in air for 2-5 h, to obtain the catalyst. Loading the noble metals Pt and Pd into a pore channel of a molecular sieve improves NOx storage capacity of a catalyst at low temperatures, and selecting a different type of molecular sieve as an NOx storage unit and increasing a roasting temperature of a molecular sieve material on which Pt and Pd are loaded significantly increases NOx storage capacity.

Integrated catalyst system for stoichiometric-burn natural gas vehicles and preparation method therefor

Tail gas treatment catalyst, preparation method therefor and use thereof

Disclosed in the present invention is a tail gas treatment catalyst. The catalyst consists of a carrier, a first catalyst, and a second catalyst. The first catalyst and the second catalyst are provided on both ends of the carrier. The first catalyst can purify pollutants in tail gas. The second catalyst can purify a byproduct, ammonia, obtained by the purification by the first catalyst and pollutants that are not completely purified by the first catalyst. The second catalyst is of a double-layer structure; the lower layer consists of an oxygen storage material, aluminum oxide, and a second active component; the second active component is a composition of Pt and Pd, or a composition of Ce, Fe, Ni and Cu; the upper layer consists of a molecular sieve and a third active component; the third active component is Cu or a composition of Cu and Fe. The tail gas treatment catalyst of the present invention has high purification treatment efficiency, and can significantly reduce the emissions of CH₄, CO, and NO_x in the tail gas, especially reduce the content of the byproduct, NH₃, so that the tail gas can meet China VI emission standards.

Molecular sieve scr catalyst and preparation method

The invention discloses a molecular sieve SCR catalyst and a preparation method, the preparation method comprising the steps of: (1) heating deionized water to 60-90° C., and adding a soluble copper salt and an additive to stir and dissolve the same to prepare a copper solution; (2) heating the deionized water to 20-90° ° C., adding a soluble yttrium salt to dissolve the same, and when maintaining the temperature, adding a molecular sieve with a silicon-aluminum ratio of ≤24 and stirring the same; when maintaining the temperature, adding a copper solution and stirring to perform ion exchange; (3) cooling the solution after the ion exchange in step (2), adding an adhesive, stirring and ball-milling the mixture, and standing to obtain a slurry; (4) coating the slurry onto a support, drying and then calcining to obtain a molecular sieve SCR catalyst. The catalyst prepared according to the present invention by using a small pore molecular sieve material with a lower silicon-aluminum ratio and adding yttrium as a second active component exhibits excellent catalytic activity for NO x at low and high temperatures, and has a wide active temperature window, high hydrothermal stability and good hydrocarbon resistance.

Integrated catalyst system for stoichiometric-burn natural gas vehicles and preparation method therefor

Disclosed in the present invention is an integrated catalyst system for stoichiometric-burn natural gas vehicles, the catalyst system consisting of a three-way catalyst, a molecular sieve catalyst, and a base body, the three-way catalyst and the molecular sieve catalyst being coated on a surface of the base body. In the integrated three-way catalyst and molecular sieve catalyst system of the present invention, at the same time that pollutants such as CO, HC, and NO x in the exhaust of stoichiometric-burn natural gas vehicles are processed, the produced byproduct NH 3 can also be processed, and the conversion rates of CO, HC, NO x , and NH 3 are high.

Ultrasonic surgical instrument and ultrasonic surgical system

Disclosed are an ultrasonic surgical instrument ( 100 ) and ultrasonic surgical system; the ultrasonic surgical instrument ( 100 ) includes a waveguide ( 1 ) rotatable around an axis and in threaded connection with a transducer ( 200 ); a force transmission mechanism is in fixed connection with the waveguide ( 1 ), which has at least one stress surface ( 41 ); a rotatable mechanism includes a pushing mechanism and a rotatable driving mechanism having at least one force applying surface ( 51 ), the applying surface ( 51 ) and the stress surface ( 41 ) are not perpendicular to the axis, and can be engaged with each other; the pushing mechanism provides a pushing force the rotatable driving mechanism towards the force transmission mechanism, and the rotatable driving mechanism can overcome the pushing force when interaction force between the applying surface ( 51 ) and the stress surface ( 41 ) is in excess of a predetermined value.