METHANOL TO GASOLINE: IMPROVED GASOLINE YIELDS

The role played by the catalyst in the mehhanol-to-gasoline process under varying conditions is significant. The mobil ZSM-5 catalyst yielded dimethyl ether as a major product in earlier experiments conducted in the Chemical Engineering Department. This prompted us to ascertain those parameters which yielded a high percentage of gasoline and minimized or eliminated dimethyl ether. A number of parameters like residence time, reaction temperature, and methanol catalyst weight ratio were studied and knowledge regarding how best a high gasoline yield could be produced was obtained. Product characterization was done by gas chromatographic analysis. GC-MS proved to be an extremely beneficial tool.     

SEPARATION AND IDENTIFICATION OF THIOLS IN FCC GASOLINE

ABSTRACT

A theoretical equation of thiol recovery efficiency for the separation of thiols from petroleum distillate is derived on the basis of the principles of reaction equilibrium and distribution equilibrium. An effective composite extractant MDS-H2O-KOH which has high efficiencies of extraction and recovery of thiols from petroleum ether as well as gasoline was selected accordingly. Thiols in FCC gasoline were separated by the selected extractant and identified with GC/FPD.     

SYNTHESIS OF HYDROCARBONS FROM DIMETHYL ETHER: SELECTIVTTIES TOWARDS LIGHT HYDROCARBONS

ABSTRACT

The depleting supplies of non-renewable petroleum reserves, as well as their escalating costs, have directed a great deal of research toward the synthesis of hydrocarbons from coal. Synthesis of methanol from coal-derived synthesis gas is a well established technology, and methanol has been used as a feedstock for the synthesis of gasoline range hydrocarbons and olefins commercially. However, an efficient hydrocarbon synthesis process has been developed at the University of Akron using dimethyl ether as the starting feedstock. This UA/ EPRI' s DTH ( Dimethyl Ether to Hydrocarbons) process has significant advantages over its counterpart methanol conversion process in the areas of heat duties, hydrocarbon selectivities, product yield, and reactor size

Lower olefins are the intermediate products in the conversion of dimethyl ether to aromatic hydrocarbons. C2-C4 olefins and paraffins can be selectively produced by varying the operating parameters of the process, viz., temperature, pressure, DME concentration in the feed, space time, catalyst-to-inert packing ratio, etc. The present work focuses on the effect of key process variables on the dimethyl ether conversion to low molecular weight hydrocarbons in a fixed bed microreactor system over ZSM-5 type zeolite catalyst. Experimental results with respect to gaseous hydrocarbon product yields and selectivities have been examined in this study     

DESIGN AND OPERATION OF A FLUIDIZED BED REACTOR MINI-PILOT PLANT FOR GASOLINE SYNTHESIS

MethanoI-to-Gasoline (MTG) process is an excellent process which produces aromatics-rich gasoline from methanol over the ZSM-5 catalyst. The methanol feed in this process is usually derived from coal or natural gas based syngas.

The dehydration of methanol to dimethyl ether (DME) is a key intermediate step in converting methanol into gasoline. The substitution of syngas-to-methanol step in the MTG process by the direct one stage conversion of syngas-to-DME is thus a very attractive option. This substitution is particularly justified on the basis of the fact that DME results in virtually identical hydrocarbon product distribution as methanol.

Synthesis of gasoline via this direct DME route has several significant advantages over the MTG process, in the areas of product yield, selectivity, overall syngas conversion, exothermicity, and reactor size. The conceptual advantages of this DME-to-gasoline (DTG) process can be demonstrated in a laboratory scale fluidized bed gasoline synthesis unit.

This paper discusses the design philosophy of the fluidized bed reactor unit and its peripherals. The fabrication, assembly, and operation of the unit have also been discussed in detail.     

直馏汽油非临氢改质技术的工业应用

摘要扬州石油化工厂20 kt／a直馏汽油非临氢改质装置的运行结果表明,石油化工科学研究院开发的RGw-l型直馏汽油非临氢改质催化剂的活性、选择性高,单程运转周期大于70 d,再生后反应性能完全恢复。改质反应产品收率高,干气产率小于2％。产品品质好,改质后汽油RoN提高30个单位以上,烯烃质量分数小于2％,是汽油降烯烃的优质调合组分;副产液化气的烷烃体积分数达95％以上,可以作为车用液化气。该催化剂还可用于含ct烯烃原料的改质。为直馏汽油和c。馏分的升值利用及炼油厂汽油降烯烃开辟了一条新途径。     

EFFECT OF METHYL TERTIARY BUTYL ETHER (MTBE) AS A GASOLINE ADDITIVE ON ENGINE PERFORMANCE AND EXHAUST EMISSIONS

ABSTRACT

The effect of blending unleaded gasoline with different proportions of methyl-t-butyl ether MTBE (10, 15 and 20 vol % ) on engine performance was studied using a fixed compression ratio SI engine (Opel 4 -cylinder ). The exhaust gases were analyzed for carbon monoxide, carbon dioxide and the hydrocarbons emitted. The results have shown that MTBE blends gave slightly better engine performance than the unleaded gasoline as evidenced by the power output. Analysis of exhaust gases shows better carbon monoxide and hydrocarbon emissions for all MTBE blends tested than unleaded gasoline. A higher carbon dioxide exhaust emission of the blends than the unleaded gasoline also confirms their better combustion. The 20 vol % MTBE blend gave the lowest carbon monoxide and hydrocarbon emissions of all blends used. A comparison was also made between a     

催化裂化操作参数对降低汽油烯烃含量的影响

针对催化裂化汽油烯烃含量较高的情况,在中型提升管催化裂化装置上,考察了原料油性质、催化剂性质、反应条件、汽油馏程等对汽油烯烃含量的影响,提出了工业生产装置降低催化裂化汽油烯烃含量的措施。研究发现,催化裂化汽油烯烃含量与氢转移指数（异丁烷／丁烯及异丁烷／异丁烯）呈线性关系,氢含量高、K值大的原料油,汽油烯烃含量较高。使用降烯烃催化剂、提高催化剂活性、提高剂油比、降低反应温度、延长反应时间、提高烃分压、提高汽油终馏点等有利于降低催化裂化汽油烯烃含量。     

Dimethyl ether in the processing of associated petroleum gas to a mixture of synthetic hydrocarbons

The development of single-stage synthesis of dimethyl ether (DME) from synthesis gas makes it possible to obtain hydrocarbons directly from DME. The effect of the nature and concentration of components of the vapor–gas mixture that arrives at the stage of DME conversion to liquid hydrocarbons on activity and selectivity of a zinc–palladium zeolite catalyst has been examined. It has been found that and increase in DME concentration to more than 20 vol % in the reaction stream leads to lowering both DME conversion and gasoline selectivity and increasing the yield of byproducts. The presence of components such as H₂, CO, H₂O in the vapor–gas mixture ensures high stability of the catalytic system. Switching from the flow-through to the recycle operation mode increases the catalyst selectivity for gasoline, decreases the formation of durene, and reduces catalyst coking.     

THE INFLUENCE OF KINETIC PARAMETERS ON THE FISCHER-TROPSCH PRODUCT DISTRIBUTION

ABSTRACT

The expected composition of Fischer-Tropsch products has been examined as a function of catalyst type, temperature, pressure and H₂/CO ratio. The complete product distribution, as well as gasoline and diesel yields as a percentage of total hydrocarbons, were calculated by applying an established distribution model to an ideal PFR reactor simulation. In this way we have examined the effect of operating conditions and the kinetic parameters of the model on the expected product distribution. This distribution is shown to be a function of the operating conditions and of catalyst formulation.

The results show that, in principle, one can make more gasoline by increasing the H₂/CO ratio and better quality gasoline by decreasing total pressure. However, for both gasoline and diesel production, there is a set of parameters which yields a maximum of these products. By understanding the influence of temperature and catalyst composition on the reaction parameters, we can predict how temperature or catalyst formulation should be changed so that the reaction parameters are shifted in the direction of maximum motor fuel yield.     

Investigation of the Operating Conditions on Decreasing FCC Gasoline Olefin Content by GOR-Q Catalyst

Abstract

Based on a fixed-fluid-bed reactor and a GOR-Q catalyst, the influence of process parameters on decreasing gasoline olefin content was studied. The results show that the catalyst had an obvious effect on the decreasing gasoline olefins. A higher catalyst-to-oil ratio, lower weighted hourly space velocity, and lower reactor temperature give rise to lower gasoline olefin content. The reduction of fluid catalytic cracking (FCC) gasoline olefin content is achieved by decreasing olefins of low carbon number. Reaction temperature under 520°C and catalyst-to-oil ratio = 7.0 for a GOR-Q catalyst are advantageous for decreasing olefin content of FCC gasoline.     

EFFECT OF MTBE BLENDING ON THE PROPERTIES OF GASOLINE

ABSTRACT

The effect of blending MTBE in the gasoline was evaluated. MTBE effectively boost the octane numbers of gasoline without adversely effecting its other properties. However, MTBE is not as efficient as leadalkyl compounds as far as the specific octane number improvements are concerned. The addition of 5 to 30 volume percent MTBE increases 1.9 to 11.8 RON of a typical gasoline. MTBE addition also extends the volume of gasoline produces for a given crude by adding volume to the gasoline pool. MTBE provides much higher FEON to the gasoline in comparison with other gasoline components. A higher FEON increases the efficiency of the engine. MTBE is not affected by the lead level of the gasoline. For this reason, lost octane in future lead reductions of the gasoline in Saudi Arabia can be made up with MTBE. MTBE addition to the Saudi gasoline increases the RVP but within the specification of the gasoline. MTBE has favorable effect on the distillation characteristics of the gasoline. MTBE addition lowers the distillation temperature which improves driveability and cold engine operation. MTBEgasoline blends were found free of gums and peroxides after long term storage and pose no phase separation problems in the presence of water. MTBE is miscible in gasoline in all proportions and its solubility in water is low.     

A SINGLE-STAGE,LIQUID-PHASE DIMETHYL ETHER SYNTHESIS PROCESS FROM SYNGAS I. DUAL CATALYTIC ACTIVITY AND PROCESS FEASIBILITY

ABSTRACT

A novel process for manufacturing dimethyl ether (DME) from CO-rich syngas in a single stage has been developed. This novel approach was based on the application of dual catalysis in the liquid phase process, in which two functionally different catalysts are slurried in the inert mineral oil. The experimental reaction rate studies for methanol and dimethyl ether synthesis were conducted in a three-phase, mechanically agitated slurry reactor. The effects of catalyst ratio, temperature, and pressure on the dual catalytic activity were studied. The experimental data bear additional significance because this is the first study of such kind to be conducted on the liquid phase methanol synthesis process.     

Amberlyst 35树脂催化剂在催化裂化轻汽油醚化装置的工业应用

介绍了阳离子交换树脂催化剂Amberlyst 35在A、B两公司催化裂化轻汽油醚化装置上工业应用的情况。工业应用结果表明:Amberlyst 35催化剂具有活性高及开工过程简单等特点,在Amberlyst 35催化剂作用下,A公司和B公司均可生产出低烯烃含量、高辛烷值的醚化汽油产品;经过三段醚化后,A公司工况一和工况二的异戊烯总转化率分别为97.59%、95.54%,甲基叔戊基醚的选择性分别为93.48%、97.15%;B公司的异戊烯总转化率为97.21%,甲基叔戊基醚的选择性为87.15%。     

焦化汽油催化裂解反应特性探析

分析了典型焦化汽油烃类组成特点,重点研究焦化汽油催化裂解反应过程中反应转化率以及低碳烯烃的产率和选择性的主要影响因素。结果表明,催化裂解反应条件下焦化汽油转化率较低,提高反应温度是提高低碳烯烃产率的有效手段,但是目标产物的选择性变化不大;采用高选择性的催化剂可以在提高乙烯和丙烯产率的同时提高其选择性,并达到少产丁烯的目的。焦化汽油的正构烷烃转化程度低,尤其是C5～C7正构烷烃转化程度不足60％,是因其分子碳链短,所形成的正碳离子的β断裂反应不易发生所致。     

催化裂化粗汽油回炼改质工艺的用能改进

 针对催化粗汽油回炼改质过程能耗偏高的现状,进行了以降低辅助提升管油/剂接触温差和优化辅助分馏塔油气热量利用为内容的过程用能改进。工程实施结果表明,利用装置低温余热提高粗汽油回炼温度,可通过多发生5.7t/h的中压蒸汽,将辅助分馏系统的较低品质热量置换出等量的反-再系统的高品质热量;同时,辅助分馏塔中段回流热和循环油浆热量的升级利用,使得催化粗汽油回炼改质工艺的用能状况大为改善。优化改进后的有效热利用提高,干气和焦炭的产率下降,使现有的50t/h粗汽油回炼改质催化装置能耗降低4.4 (kg 标油)/ (t原料),且汽油质量得到提高。     

Ni/HZSM-5上裂解汽油选择加氢裂化的研究

在连续流动固定床装置上,探讨了非贵金属Ni/HZSM-5催化剂对裂解汽油选择加氢裂化反应的特征,考察了镍含量、温度、压力、空速及氢烃体积比等参数的影响。随镍含量的增加,裂解汽油中C6+非芳烃转化率先增加后减小,镍含量为2.1%左右较为适宜。工艺条件中温度和压力的影响较大,空速次之,氢烃体积比最小。在380 ℃、3.0 MPa、质量空速1.245 h-1、氢烃体积比1 000的条件下,以镍含量为2.1%的Ni/HZSM-5为催化剂,65 h内裂解汽油中C6+非芳烃组分转化率保持在95%以上,而芳烃转化率仅有13%; 加氢裂化产物中,C2+正构烷烃达80.96%,其中丙烷60.71%,而甲烷和异构烷烃较少。这表明非贵金属Ni/HZSM-5催化剂可高选择性地裂化C6+非芳烃,适用于裂解汽油加氢裂化制备芳烃联产低碳烷烃。     

The Synthesis and Application of CuO-ZnO/HZSM-5 Catalyst With Core-shell Structure

Abstract

CuO-ZnO/HZSM-5 catalyst was prepared hydrothermally by CuO-ZnO as the core and HZSM-5 as the shell and used in hydrogenation of CO₂ to produce dimethyl ether. The morphologies, phase structure, and acid properties of this catalyst were investigated with transmission electron microscopy, X-ray diffraction, and NH₃-temperature programmed desorption in detail. The experimental results showed that the catalyst exhibited higher catalytic activity compared with the catalysts prepared by traditional mechanically mixing method and impregnation method.     

Effect of Feedstock and Gas Atmosphere Composition on Selectivity and Distribution of Hydrocarbon Groups in Gasoline Synthesis from Oxygenates

Gasoline has been synthesized from oxygenates (dimethyl ether and methanol) on a HZSM-5 zeolite catalyst, modified by palladium and zinc, in a micropilot unit operating in the continuous recycle flow mode. The influence of the gas atmosphere composition—synthesis gas, hydrogen, and methane—on the gasoline selectivity, and on-stream stability of the catalyst has been determined for dimethyl ether (DME) used as a feedstock. The hydrocarbon composition and the carbon distribution in the products have been compared using DME and methanol as the feedstock in the synthesis-gas atmosphere. It has been shown that the higher gasoline selectivity production in the case of methanol is due to the higher concentration of aromatic hydrocarbons, which is achieved by decreasing the intensity of their dealkylation.     

提高汽油辛烷值的芳构化技术

介绍了洛阳石油化工工程公司炼制研究所开发的劣质汽油芳构化改质技术,利用芳构化技术改质直馏汽油,可以得到64.4％的高辛烷值汽油,并副产30.2％的液化石油气,所产高辛烷值汽油基本符合我国90号无铅汽油质量要求。试验证明新开发的催化剂具有良好的活性和稳定性,催化剂单程操作周期在15天以上。该技术为炼油厂汽油质量的升级开辟了一条新路,具有推广前景。     

降低催化裂化汽油烯烃含量的中型试验研究

在中型提升管催化裂化试验装置上详细考察了原料油性质、催化剂类型以及操作条件对催化裂化汽油烯烃含量的影响.原料油性质是决定催化裂化汽油烯烃含量高低的关键,选择氢转移活性高的稀土Y型催化剂是降低催化裂化汽油烯烃含量的有效措施.选择适宜的反应温度和油气停留时间,适当提高剂油比和催化剂活性,均可以在一定程度上降低催化裂化汽油烯烃含量.