Adsorptive removal of nitrogen-containing compounds from fuel by metal-organic frameworks

The adsorptive denitrogenation from fuels over three metal-organic frameworks(MIL-96(Al),MIL-53(Al)and MIL-101(Cr))was studied by batch adsorption experiments.Four nitrogen-containing compounds(NCCs)pyridine,pyrrole,quinoline and indole were used as model NCCs in fuels to study the adsorption mechanism.The physicochemical properties of the adsorbents were characterized by XRD,N2physical adsorption,FT-IR spectrum and Hammett indicator method.The metal-organic frameworks(MOFs),especially the MIL-101(Cr)containing Lewis acid sites as well as high specific surface area,can adsorb large quantities of NCCs from fuels.In addition,the adsorptive capacity over MIL-101(Cr)will be different for NCCs with different basicity.The stronger basicity of the NCC is,the more it can be absorbed over MIL-101(Cr).Furthermore,pore size and shape also affect the adsorption capacity for a given adsorbate,which can be proved by the adsorption over MIL-53(Al)and MIL-96(Al).The pseudo-second-order kinetic model and Langmuir equation can be used to describe kinetics and thermodynamics of the adsorption process,respectively.Finally,the regeneration of the used adsorbent has been conducted successfully by just washing it with ethanol.

Commercial Application of the Second Generation RHT Catalysts for Hydroprocessing the Residue with Low Sulfur and High Nitrogen Contents

The RHT technology and the second generation RHT catalysts were applied in design of an 1.7Mt/a VRDS unit at the SINOPEC Changling Branch Co. The commercial application result demonstrated that the RHT catalysts showed good activity and stability in processing low-sulfur and high-nitrogen residue. The first long period run of unit for processing high Fe and high Ca content residue was achieved. The reasons for excessive pressure drop of R-101 were ascribed to Fe and Ca deposition as well as coke formation.

Removal of Nitrogen Compounds from Shale Diesel Fraction Using Ionic Liquid [C_4mim]HSO_4

Ionic liquid(IL) 1-butyl-3-methylimidazolium hydrosulphate([C_4mim]HSO_4) was synthesized and its denitrogenation performance was investigated for diesel fraction with high content of nitride from oil shale. The effects of the temperature, the mass ratio of oil to IL, the mass ratio of water to IL, the extraction time, the settling time and the regeneration of IL on the N-removal efficiency were studied. Experimental results showed that the ionic liquid [C_4mim]HSO_4 exhibited excellent denitrogenation performance, and about a 90% basic N-extraction efficiency and a 71% total N-extraction efficiency were achieved under the conditions covering a temperature of 30 ℃, an oil/IL mass ratio of 7:1, a H_2O/ IL mass ratio of 2:1, an extraction time of 20 min and a settling time of 120 min. In addition, the basic N-removal efficiency can still reach 74% during five recycles of the ionic liquid.

Extractive denitrogenation of shale oil using imidazolium ionic liquids

The potential applications of shale oil as a substitute energy source are adversely influenced due to its high nitrogen content.In this work,four imidazolium ionic liquids(ILs),i.e.,1-butyl-3-methylimidazolium chloride([Bmim]Cl),1-butyl-3-methylimidazolium acetate([Bmim]Ac),1-butyl-3-methylimidazolium acetate/ZnAc2([Bmim]Ac/ZnAc2)and 1-butyl-3-methylimidazolium chloride/ZnAc2([Bmim]Cl/ZnAc2),were used to extract the basic nitrides and neutral nitrides from shale oil.The influence of extraction time,temperature,properties of N-compounds,ILs structure,mass ratio of IL/oil,multiple cycles of denitrogenation,physical mixing of ILs and ILs recyclability on extractive denitrogenation was systematically investigated.The denitrogenation performance of all ILs was determined and investigated from micro-level view withσ-profile.It was observed that,ILs composed of anions with weaker HB acceptor capacity,have the higher N-extraction efficiency to the neutral nitrogen compounds with weaker HB acceptor capacity.More than 96%N-extraction efficiency was achieved at the end of a single extraction cycle for time<10 min under 40℃C and 1:1 of IL:oil(w/w),especially 100%N-extraction efficiency was realized for carbazole and indole.The N-extraction efficiency up to 60.1%and 53.7%for real shale oil was realized by[Bmim]Ac and[Bmim]Ac/ZnAc2,respectively,which are about 10%better than other non-hydrodenitrogenation technologies.Moreover,[Bmim]Ac and[Bmim]Ac/ZnAc2 exhibited almost the same extractive denitrogenation performance after regeneration.This work has developed a new approach to lessen the nitrogen content of shale oil effectively and economically.

Effective adsorptive denitrogenation from model fuels over yttrium ion-exchanged Y zeolite

The adsorption removal of indole and quinoline in octane with and without toluene over zeolites NaY and Yttrium Ion-exchanged Y(YY)using batch adsorption experiments was studied at 25℃and 0.1 MPa.YY was prepared by treating NaY with Y(NO3)3 solution twice via liquid ion-exchange method.NaY and YY were both characterized by XRD,SEM,N2 adsorption,XRF,NH3-TPD,and pyridine-FTIR techniques.Adsorption isotherms of indole,quinoline and toluene in octane were conducted at 25.0℃to explain the influence of toluene on nitrogen removal over NaY and YY.The partial destruct of the crystalline structure of NaY was observed after the introduction of yttrium ion,which led to an evident decline in BET surface area and pore volume of YY.Strong Br?nsted acidity and medium Lewis acidity were introduced by yttrium ion-exchange.Though the specific surface area and pore volume of YY were much lower than those of NaY,YY exhibited equivalent adsorption capacities for indole and quinoline as NaY in model fuels without toluene.In the presence of 20 vol%toluene,however,YY exhibited much higher adsorption capacities for indole and quinoline than NaY,especially in the case of quinoline.The improved toluene-tolerant of YY was ascribed to the strong acid–base interaction between YY and quinoline and the decreased adsorption strength between YY and toluene.

Removal of Nitride from Shale Diesel Fraction with FeCl3-Based Ionic Liquids

FeCl3-based ionic liquid [Bmim]Br/FeCl3 with lower viscosity was synthesized and its structure was character-ized with FT-IR spectroscopy. The denitrogenation performance of the ionic liquid was investigated using the Fushun shale diesel fraction with high nitrogen content. Experimental results showed that the ionic liquid presented good denitrogenation performance and the basic N and total N removal efficiency can reach 95.29% and 89.77% under conditions covering a tem-perature of 30 ℃, an IL/oil mass ratio of 1:1, an extraction time of 30 min, and a settling time of 2 h. Correspondingly, the basic N and total N contents in shale diesel fraction dropped from the original 5454 μg/g and 9832 μg/g to 257 μg/g and 1006 μg/g, respectively. In addition, the basic-N removal efficiency can still reach 60% at an IL/oil mass ratio of 1:7 during four recycles of the ionic liquid.

Removal of Basic Nitrogen Compounds from Diesel Fraction with NMP-0.5ZnCl_(2) Coordinated Ionic Liquid

An inexpensive coordinated ionic liquid NMP-0.5ZnCl_(2) was synthesized by reacting N-methyl-pyrrolidone with anhydrous ZnCl_(2),and its structure was characterized with FT-IR spectroscopy.The performance of IL for removing basic nitrogen compounds from model oil containing quinoline and actual coker diesel was studied.Experimental results showed that the IL,NMP-0.5ZnCl_(2),exhibited a good denitrogenation performance,which can be attributed to its low viscosity and unoccupied orbitals of Zn ion,while obtaining a 99.68%quinoline removal efficiency under conditions covering a temperature of 50℃,an IL/model oil mass ratio of 1:2,and a reaction time of 30 min.In the case of coker diesel,above a 91%basic N-removal efficiency(with N-content reduced from 536μg/g to 47μg/g)was realized by the IL after 5-stage extraction.Moreover,the quinoline extraction efficiency could still reach 96.73%during four recycles of the IL.

Photocatalytic Denitrogenation of Model Oil over Cu_2O/TiO_2

Cu2O/TiO2 catalyst was prepared by the modification of TiO2 with Cu（NO3）2 through combined ultrasonic resonance and impregnation method. The samples were characterized by X-ray diffraction （XRD）, N2 adsorption-desorption （BET）, UV-vis diffuse reflectance spectroscopy （DRS） and X-ray photoelectron spectroscopy （XPS）. The catalyst was used for photocatalysis denitrogenation of pyridine in an octane solution under visible light. Pyridine was taken as the probe molecule to study the denitrogenation property of Cu2O/TiO2. The best performance in the photocatalytic denitrogenation of model oil containing pyridine was 85% under the conditions of Cu loading concentration of 0.5 mol/L, calcination temperature of 400 ℃ and calcination time of 5 h.

Review of Denitrogenation of Algae Biocrude Produced by Hydrothermal Liquefaction

Recently, algae biocrude has drawn considerable attention as algae are considered to be one of the major fuel feedstocks of the future. Based on some impressive results achieved under appropriate conditions, the algae hydrothermal liquefaction(HTL) process has proven to be energy efficient. However, the HTL of biocrude is characterized by a high nitrogen content, which prevents its use in the field of transportation due to the associated nitrogen oxide emissions. Despite this toxicity, few research efforts have focused on the denitrogenation of algae biocrude. In this study, we review the effect of different strain-specific operation parameters and process upgrades with respect to the nitrogen content of biocrude. To achieve denitrogenation, chemical engineering may be required, although some improvements in biocrude properties have been achieved in a number of process upgrades. The use of similar successful pathways has the potential to improve the field of HTL biocrude denitrogenation. These methods, including the adsorptive and extractive denitrogenations of fossil fuels and the hydrodenitrogenation of the main nitrogen compounds, are helpful for developing a better understanding of the potential of denitrogenation for algae HTL biocrude. We also recommend the use of some available catalysts and corresponding operation parameters to promote continued research on denitrogenation.

Multi-response optimization of MIL-101 synthesis for selectively adsorbing N-compounds from fuels

In this work,MIL-101,a metal organic framework,has been synthesized and examined in the adsorptive denitrogenation process.Due to the importance of adsorption capacity and selectivity,the effects of synthesis parameters including metal type,reagent ratio,time and temperature on the MIL-101 performance were investigated by measuring quinoline(QUI)separation from iso-octane.The optimum conditions were determined using a Taguchi experimental design and the multiresponse optimization(multivariate statistical)method.Based on the arithmetic mean of normalized QUI adsorption capacity and QUI/dibenzothiophene(DBT)selectivity,as the objective function,the optimum value of synthesis parameters were found to be manganese as metal type in the structure,180°C for synthesis temperature,15h for synthesis time and 1.00 for reagent molar ratio.Under these conditions,QUI adsorption capacity and QUI/DBT selectivity were 19.3 mg-N/g-Ads.and 24.6,respectively.Accordingly,the arithmetic mean between normalized values of these measured parameters was equal to 1.10,which is in good agreement with the predicted value.The MIL-101 produced under optimum conditions was characterized by determining its specific surface area,X-ray powder diffraction patterns and Fourier transform infrared spectroscopy.Finally,isotherm and kinetic studies indicate that the Langmuir isotherm and pseudo-first-order model can successfully describe the experimental data.

Denitrogenization from Liquid Steel by Fluxes Treatment

By measuring the solubility of nitrogen in BaO-contained and TiO_2-contained fluxes at 1623K, the nitride capacity and nitrogen distribution ratio were calculated. Both fluxes had high nitride capacity and nitrogen distribution ratio. The results indicated that Both fluxes treatment were available for denitrogenizing steel. The kinetic studies about denitrogenization showed that nitrogen transfer in liquid steel is the controlled step of denitrogenization reaction, so to improve the mass transfer condition in liquid steel could accelerate the rate of denitrogenization. Under proper test conditions, it was proved to be possible to remove nitrogen over 70 percent from steel with TiO_2 contained fluxes.

Removal of Basic and Non-Basic Nitrogen Compounds from Model Oil by FeCl_(3)-Based Ionic Liquids

The low-viscosity FeCl_(3)-based ionic liquids(ILs)prepared from the interaction of anhydrous FeCl_(3) and alkyl imidazolium bromide([1-alkyl-3-methyl-imidazolium]Br,alkyl=ethyl,butyl,hexyl,octyl)are highly effective for the denitrogenation of model oil containing quinoline or indole.The results indicate that the chain length of the alkyl group on the imidazolium cation has little influence on the N-extraction efficiency.With the selected IL[Bmim]Br/FeCl_(3),up to 99.1%of N-extraction efficiency from model oil containing quinoline can be attained at an extraction temperature of 30°C with an IL/oil mass ratio of 1/7 and an extraction time of 30 min.The indole extraction efficiency reaches 98.9%at an IL/oil mass ratio of 1:1.Moreover,the quinoline extraction efficiency remains as high as 92.3%after the IL has been recycled four times.

Behaviors of Denitrogenation in RH-MFB

According to the analysis related to kinetic mechanism of vacuum denitrogenation and combining with the actual production of RH-MFB （a combination of Ruhstahl-Hausen vacuum degassing process with a multifunctional oxygen lance） at Liansteel, the limit step and model equation of vacuum denitrogenation are determined. Meanwhile, the influencing factors of nitrogen removal from liquid steel in vacuum of RH-MFB are analyzed. The results show that the limit step of vacuum denitrogenation in RH-MFB is the mass transfer of nitrogen in liquid boundary layer and the reaction follows first order kinetics. Keeping the necessary circulation time under the working pressure （67 Pa） is helpful to nitrogen removal from steel. The oxygen content in molten steel has little influence on the removal of ni-trogen after deep deoxidation, while the sulphur content in liquid steel is always relatively low and has little effect on denitrogenation. The sharp decrease of carbon content in steel drives the process of denitrogenation reaction so as to exhibit a faster denitrogenation rate. The interracial chemical reaction and argon blowing play a major role in the ni-trogen removal when the carbon content in liquid steel is stable.

Research on Refining Technology of Clean Steel in a Plasma Ladle Furnace

The clean steel refining tests carried out in a 100 kg plasma ladle furnace(PLF)were to show the metallurgical effects of the different plasma gases such as Ar-H_2 and Ar-CO_2.The variations of carbon,nitrogen contents in steels and the mechanism of denitrogenation were studied.Compared with the conventional ladle furnace,when the plasma gases were injected into the ladle furnace,there was a decarburization process,the carburetion rates were reduced obviously. The carburetion rate is 3.6×10^(-6) per minute for the steel heated by conventional LF,and is 2.20 and 1.35 times of the heats blown 85%Ar-15%H_2 and 85%Ar-15%CO_2,respectively.When the plasma ladle furnace operated with Ar-H_2 plasma gas, the denitrogenation of the molten steel occurs.The lowest denitrogenation rate is 0.30×10^(-6)per minute when Ar-H_2 gas mixtures were used.The main reactant gas is monatomic hydrogen and the main product of denitrogenation is NH_3 for Ar-H_2 injection.