6 results about "No conversion" patented technology

The invention discloses a preparation method and application of a MnCeNbTiOx catalyst for degrading NO by NH3-SCR (selective catalytic reduction), particularly relates to a catalyst for effectively degrading an atmospheric pollutant NO, and belongs to the field of atmospheric pollution treatment and environment-friendly catalytic environment. The catalyst is prepared by using Mn as a main active component, Ti as a carrier and transition metals Ce and Nb as auxiliaries through a coprecipitation method. The preparation method comprises the following steps: firstly, weighing an active component Mn (NO3) 2.4 H2O, an auxiliary agent Ce (NO3) 4.6 H2O and an auxiliary agent C10H5NbO20 according to a stoichiometric ratio, adding a proper amount of deionized water to completely dissolve, then adding a metered Ti (SO4) 2 carrier, stirring until the Ti (SO4) 2 carrier is completely dissolved, dropwise adding ammonia water under the condition of stirring to adjust the pH value to be approximately equal to 10, then stirring the obtained solution for 1 hour, aging for 1 hour, transferring into a centrifugal tube, centrifuging, washing to be neutral, and drying to obtain the catalyst. And placing the obtained catalyst sample in an oven at 110 DEG C for overnight drying, then taking out the dried catalyst sample, grinding the dried catalyst sample into powder, placing the powder in a muffle furnace, roasting the powder at 500 DEG C for 5 h, and naturally cooling the powder to obtain the MnCeNbTiOx catalyst. The MnCeNbTiOx catalyst disclosed by the invention has better low-temperature activity and a wider operating temperature window, can effectively remove NO in the tail gas of the industrial furnace, achieves the highest NO conversion rate of 98% at the temperature of 250 DEG C, and has a T80 operating temperature window of 175-435 DEG C. Meanwhile, characterization results show that after the auxiliaries Ce and Nb are added, the catalyst mainly presents an amorphous structure, the oxidation-reduction performance of the catalyst and the interaction force among the components are enhanced, and improvement of the denitration activity of the catalyst is facilitated.

The invention provides a zeolite-based catalyst and a preparation method thereof. According to the catalyst, flaky ZSM-5 zeolite is taken as a carrier, and a composite material with a synergistic catalysis effect is formed by loading bimetallic active components of Cu and Fe step by step. The NO conversion rate and N2 selectivity of the catalyst in the temperature range of 250-400 DEG C are both kept at 95% or above, and the catalyst has the advantages of being high in low-temperature activity, high in wide-temperature-range applicability, good in hydrothermal stability and excellent in poisoning resistance. The preparation method comprises seed crystal induction-hydrothermal crystallization synthesis of flaky ZSM-5 zeolite and a step-by-step metal loading process of Cu ion exchange and Fe dipping-evaporation-calcination, and the process is simple, convenient and controllable and is suitable for industrial application.

The present invention discloses a copper-based SSZ-39 molecular sieve catalyst, its preparation method and application, belonging to the technical field of molecular sieves. The catalyst includes a carrier, the carrier is SSZ-39 molecular sieve, the active component is copper, and the promoter components are niobium and manganese; the catalyst is a cuboid with a grain side length of 0.4-0.6 μm and a height of 0.1-0.2 μm; based on the total mass of the catalyst, the mass fraction of the active component copper is 2.42-2.72 wt%, the mass fraction of the promoter component niobium is 0.27-0.37 wt%, and the mass fraction of the promoter component manganese is 1.21-1.33 wt%. The catalyst of the present invention has very excellent low-temperature denitration activity, and the lowest ignition temperature T 50 is lower than 90 °C, and the NO conversion rate reaches more than 90% in a wide temperature range of 128-500 °C.

The invention discloses a preparation method and application of a wide-temperature-range Mn-based NH3-SCR denitration catalyst, particularly relates to a catalyst for effectively degrading an atmospheric pollutant NO, and belongs to the field of atmospheric pollution treatment and environment-friendly catalytic environment. According to the catalyst, firstly, a coprecipitation method is adopted, non-toxic Mn with good low-temperature activity and low cost is selected as a metal active component, Ti (SO4) 2 is selected as a carrier precursor, Ce and Nb are selected as auxiliaries, the proportion of all the components is optimized, and the Mn0. 1Ce0. 1Nb0. 03TiOx-CP catalyst with better activity is prepared. However, the low-temperature activity of the catalyst still needs to be improved, so that the Mn0. 1Ce0. 1Nb0. 03TiOx-CP catalyst is subjected to enhanced modification treatment by adopting different preparation methods, the influence of different precipitators, different pH values and different aging time on the activity of the catalyst is discussed, and a series of catalysts are prepared. According to the present invention, the Mn0. 1Ce0. 1Nb0. 03TiOx-CP catalyst with the optimal low temperature activity and the widest operation temperature window is synthesized, the highest NO conversion rate at 250 DEG C can achieve 98.5%, and the T80 temperature interval is 166-443 DEG C. Compared with the Mn0. 1Ce0. 1Nb0. 03TiOx-CP catalyst prepared by using the conventional co-precipitation method, the low temperature activity is further reduced, and the T80 operation temperature interval is further broadened. In addition, the preparation method is simple in process and suitable for industrial production, and preparation conditions are easy to control. Meanwhile, a characterization result shows that the catalyst prepared by adopting a reverse coprecipitation method mainly presents an amorphous structure, so that the oxidation-reduction performance of the catalyst and the interaction force among the components are enhanced, and the denitration activity of the catalyst is favorably improved.

This invention relates to a diesel oxidation catalyst that enhances NO oxidation capacity, its preparation method, and its application. The diesel oxidation catalyst comprises layered and regionalized coatings A, B, C, and optionally D. Based on the weight content of precious metals per unit volume, the sum of the loadings of platinum and palladium, the active components of precious metals, in coating B is greater than or equal to the sum of the loadings of platinum and palladium, the active components of precious metals, in coating A, and the sum of the loadings of platinum and palladium, the active components of precious metals, in coating C is greater than the sum of the loadings of platinum and palladium, the active components of precious metals, in coating B. This structural design significantly improves the low-temperature NO conversion capacity. The inclusion of coating C ensures stable fuel ignition performance, while coating D regulates the exhaust gas flow field. This catalyst has a simple preparation process, excellent performance, and can achieve a high NO conversion rate while meeting fuel ignition requirements under low precious metal loading conditions, making it suitable for industrial production applications.

The invention relates to the technical field of denitration catalytic materials, and discloses a preparation method of a denitration catalytic material special for emission of a methanol internal combustion engine, and the preparation method comprises the following steps: S1, preparing a multi-element synergistic precursor mixed solution: sequentially mixing a carrier precursor, an active metal salt, a main ligand, a double-dynamic auxiliary ligand and a coordination regulator to obtain the multi-element synergistic precursor mixed solution; adjusting the pH value, and stirring to obtain a transparent and uniform multi-element synergistic precursor mixed solution; s2, gradient coordination polymerization reaction: putting the multi-element synergistic precursor mixed solution into a closed high-pressure reaction kettle, and reacting by adopting a stepped heating polymerization process to obtain an integrated gel product; s3, doping gas assisted low-temperature plasma activation; and S4, surface acid-base modification post-treatment. Through the synergistic effect of the double-dynamic auxiliary ligand and the coordination regulator, the gradient coordination polymerization process is matched to regulate and control the precursor structure, the reaction induction period is shortened, the NO conversion rate in the low-temperature interval is increased, and the problem that the low-temperature exhaust denitration reaction speed of the methanol internal combustion engine is low is solved.