Approximate Expressions to Evaluate the Performance in Butene-1 Purification Units

1 INTRODUCTIONSelective hydrogenatioll of small amounts of butynes and butadiene is industrially employedfor obtaining high purity butene-l used as co-monomer in the production of linear low-densitypolyethyene.For this purpose,the content of vinylacetylene.butyne-l and 1,3-butadiene presentin the process stream should be reduced to a few tens of ppm.     

正丁烷及丁烯-1在不同硅铝比ZSM-5分子筛上吸附的实验与模型

Four ZSM-5 zeolite catalysts with different Si/Al ratios for the catalytic cracking of C4 fractions to produce ethylene and propylene were prepared in this study.First,the adsorption isotherms of pure n-butane and butene-1 and their mixtures on these catalysts at 300K and p=0—100kPa were measured using the intelligent gravimetric analyzer.The experimental results indicate that the presence of Al can significantly affect the adsorption of butene-1 than that of n-butane on ZSM-5 zeolites.Then,the double Langmuir（DL）model was applied to study the pure gas adsorption on ZSM-5 zeolites for pure n-butane and butene-1.By combining the DL model with the ideal adsorbed solution theory（IAST）,the IAST-DL model was applied to model the butene-1（1）/n-butane（2）binary mixture adsorption on ZSM-5 zeolites with different Si/Al ratios.The calculated results are in good agreement with the experimental data,indicating that the IAST-DL model is effective for the present systems.Finally,the adsorption over a wide range of variables was predicted at low pressure and 300K by the model proposed.It is found that the selectivity of butene-1 over n-butane increases linearly with the decrease of Si/Al ratio.A correlation between the selectivity and Si/Al ratio of the sample was proposed at 300K and p=0.08MPa.     

正丁烷和丁烯-1在不同Si/Al比ZSM-5分子筛上的吸附和扩散行为

以应用于烯烃催化裂解工艺中的具有独特择形性和酸性的ZSM-5分子筛为研究对象,采用重力分析仪在275, 288及300 K下对碳四烃(以正丁烷和丁烯-1为代表)在不同硅/铝比ZSM-5分子筛内的吸附和扩散行为进行了研究. 建立了正丁烷和丁烯-1在ZSM-5分子筛上的双朗格缪尔吸附模型. 同时,运用Fick扩散模型关联得到了正丁烷及丁烯-1在ZSM-5分子筛内的扩散系数. 结果表明,正丁烷及丁烯-1在ZSM-5分子筛内的扩散属于晶体扩散,二者的扩散系数在10-14 m2/s数量级,正丁烷的扩散速率大于丁烯-1. 正丁烷与丁烯-1在ZSM-5分子筛内的扩散速率均随温度的增加而增加,随着体系平衡压力的增加先增加后减小,而且二者的扩散系数随样品硅/铝比的增加而增加. 研究结果为碳四烃催化裂解工艺提供了相关的基础工程数据.     

Kinetics of the melt – Form II phase transition in isotactic random butene-1/ethylene copolymers

The kinetics of formation of the Form II mesophase from the melt has been investigated as a function of the concentration of ethylene chain defects in isotactic random butene-1/ethylene copolymers, using standard and fast scanning chip calorimetry. Presence of ethylene co-units in the butene-1 chain leads to a distinct reduction of the melt – Form II phase transformation rate which has been quantified by evaluation of the critical cooling rate to suppress ordering, and by isothermal analysis of half-times of Form II mesophase formation. For the first time, the temperature-dependence of the rate of Form II mesophase formation has been evaluated for butene-1/ethylene random copolymers and the butene-1 homopolymer. This study needs to be considered as a complementary addendum to former work about the Form II to Form I polymorphic transformation in isotactic random butene-1/ethylene copolymers.     

Microstructural characterization of propylene–butene-1 copolymer using temperature rising elution fractionation

Propylene–butene-1 copolymer (PBC) prepared with a titanium catalyst system was fractionated by temperature rising elution fractionation (TREF) over a temperature range of 5–80°C. PBC was shown to have a wide composition distribution ranging between 12–47 mol % of butene-1. Most of the fractions showed nearly the same crystallinity regardless of the butene-1 content. However, the solubility of the crystalline parts, which turned out to be the driving force for the fractionation, varied over the butene-1 content. Evidence that PBC shows isomorphism was obtained by the analysis of fractionated polymers, using ¹³C nuclear magnetic resonance spectrometry, X-ray diffraction, differential scanning calorimetry, and gel permeation chromatography. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 1493–1501, 1998     

乙烯二聚制高纯丁烯－1技术经济评价

本文对生产高纯度丁烯－１的Ａｌｐｈａｂｎｔｏｌ工艺进行了技术经济评价，认为该工艺条件简单、反应条件温和，而且投资少，所以很适合事在发展中国家应用。     

Infrared determination of the composition of copolymers and terpolymers of propene and butene-1 with and without octene-1

An infrared spectrophotometer was calibrated for the quantitative determination of butene-1 in copolymers with propene, and of butene-1 and limited concentrations of octene-1 in terpolymers with propene. ¹⁴C-tagged standards were used for the butene-1 calibration while standards for the octene-1 calibration were prepared from a homopolymer by blending. Films were pressed from the standards, and the absorbance per mil thickness was correlated with composition. For our instrument, wt-% C₄ = 510 (A/mil) at 766 cm^?1, and wt-% C₈ = 539 (A/mil) at 725 cm^?1. No special steps were required to eliminate the effects of crystallinity.     

Alkylation of benzene and toluene with lower olefins

The kinetics of alkylation of benzene and toluene with propene, butene-1 and butene-2, in the presence of sulfuric acid as a catalyst, was studied in a     

丁二烯装置优化方案的制定与实施

为了使丁二烯装置安全平稳长周期高负荷运行 ,生产出更多更好的产品 ,占领国内市场 ;同时为丁烯 - 1装置提供合格的抽余C4 原料 ,所以要对丁二烯装置进行优化 ,制定优化方案 ,从而提出最佳操作点和操作参数 ,降低生产成本 ,追求装置最佳经济效益。根据实际需要及可操作性 ,我们将装置分为几个单元 ,分别进行优化考核 ,最终达到总体的优化     

Properties of solution grown crystals of isotactic propylene/butene-1 copolymers

The external habit of solution grown crystals of isotactic propylene/butene-1 copolymers have been investigated together with some thermodynamic quantities. The dissolution temperature, the density and the apparent enthalpy of fusion of the crystals of copolymers show a eutectic point corresponding to a composition of ～48 % w/w in butene-1. Wide-angle X-ray diffraction analysis of crystal aggregates has been carried out and the results compared with those from the bulk material. An expansion of the unit cell and a contraction is observed for the polypropylene and poly(butene-1) like phases respectively. The values of the $\text{b}$ axis of the unit cell of polypropylene-like phase and of $\text{a}$ sin β, calculated from the spacing of (110), (040), (130) reflections, as functions of the composition agree with those calculated by Turner-Jones on bulk materials. This result indicates that the process and the mechanism of formation of crystals from dilute solution and from the melt is fundamentally the same. Small-angle X-ray diffraction analysis leads to the conclusion that the ratio $\text{σ}{}_{\mathrm{e}}\text{ΔH}{}_{\mathrm{f}}$ drastically increases with increase in the concentration of butene-1 units in the case of polypropylene-like phase, and of propylene units for the poly(butene-1)-like phase, along the chain of the copolymers.     

Modelling of butene-1 dehydrogenation in a fixed bed reactor — bed and pellet profiles

A homogeneous model incorporating the Dumez & Froment kinetics has been proposed for the butene-1 dehydrogenation reaction over a commercial chromia-alumina catalyst. The model predicts bed and pellet concentration and temperature profiles. While the temperature profiles obtained suggest a temperature minimum in the reactor, the pellet remains nearly isothermal. Under the condition used in this study, a series type of coke deposition is obtained. A comparison between experimental results obtained using the neutron attenuation technique and theoretical coke profiles reveals excellent agreement and confirms the validity of the model and the kinetics employed.     

聚丙烯装置三元共聚产品生产可行性分析及展望

通过对聚丙烯三元共聚产品、市场现状分析及国内聚丙烯装置三元共聚产品生产现状介绍引出对抚顺石化公司乙烯化工厂聚丙烯装置三元共聚产品生产可行性分析,并提出抚顺聚丙烯装置三元共聚生产改造方案及目前项目进展情况,     

乙烯-丙烯-1-丁烯三元共聚合

采用自制的ziegler-Natta催化剂催化乙烯-丙烯-1-丁烯三元共聚合.考察了1-丁烯/丙烯、铝钛比、反应温度和压力等对三元共聚合的影响.结果表明.三元共聚物中支化度约为26门000 C,其中乙基支链为18/1 000 C、丙基支链为8/1 000 C.在聚合温度为60℃、压力为0.8 MPa、乙烯分压百分数为70%、1-丁烯分压百分数为5.7%和丙烯分压百分数为24.3%时,催化活性最高,为10.5 kg/g.当n(Al)/n(Ti)大于100时,催化活性增加趋势变缓.聚合压力超过0.8 MPa时,催化活性变化不大.聚合平行实验结果表明,上述条件稳定,所得三元共聚物的表观密度为0.32g/cm3,拉伸强度为11～12 MPa、断裂伸长率为540%～560%.     

Ti alkoxide-based catalyst system in selective ethylene dimerization: High performance through modifying by alkylsilanes

Butene-1 production through a selective ethylene dimerization is one of the largest industrial processes, which is catalyzed by homogeneous catalyst system. The common industrial catalyst system is comprised of Ti alkoxide-based catalysts in combination with AlEt₃ as an activator. In this study, the alkylsilanes were used as novel improving agents in the catalyst system for highly selective ethylene dimerization to butene-1. The nature and concentration of alkylsilanes on the dimerization rate, catalyst yield, by-product production, and selectivity to butene-1 were investigated in detail. It was found that alkylsilanes improved the productivity and selectivity of the catalyst. Moreover, the content of the solid by-product considerably decreased. The performance of the modified catalyst system was noticeably higher than that of the nonmodified one. Totally, it was proved that alkylsilanes could play a modifying role in the selective ethylene catalytic dimerization process.     

Degree of comonomer inclusion into lamella crystal for propylene/olefin copolymers

Copolymers of propylene with ethylene, butene-1, hexene-1, and octene-1 were synthesized with isospecific metallocene catalyst system. Crystalline structure of the melt-crystallized samples was investigated from the viewpoint of the comonomer location in a solid-state of the copolymers, using the fuming nitric acid (FNA) etching technique followed by ¹³C NMR spectrum measurement. It was found that the copolymers were oxidatively degraded with FNA at 50 °C and the residue after etching was corresponding to the lamella crystal of the original state. ¹³C NMR spectrum of the residue revealed that all kinds of comonomer used here were located not only in the amorphous phase but also in the crystalline core. Among comonomers, butene-1 is favorably incorporated in the crystalline phase with the expansion of the crystal lattice, and the amount of comonomer in the crystal is comparable with that in the amorphous phase. Ethylene, hexene-1 and octene-1 were also found to be included into the crystal, but the degree of inclusion in the crystal was much less than that of butene-1.

Considering both the continuous increase of the weight loss and the saturation of the molecular weight decrease of the residue during an etching time-course, a plausible mechanism for the FNA degradation of the propylene copolymers was proposed.     

Transition metal salts of heteropoly acids as palladium co-catalysts for Wacker oxidation of butene-1 to MEK

The transition metal salts of heteropoly acids have been applied as palladium re-oxidants in heterogeneous solid Wacker catalysts for the oxidation of butene-1 to MEK. Silica, γ-alumina and titania were used as supports for the Pd/MeHPMoV_x system. The influence of cations bonded to heteropoly anions and also the effect of the catalysts acidity on the butene-1 to MEK oxidation have been elucidated. This revised version was published online in July 2006 with corrections to the Cover Date.     

Morphological studies of poly(olefin sulfones) by light scattering

Poly(olefin sulfones) are readily degraded by an electron beam and thus could be used as electron beam resists. However, films greater than 3000 Å thick crack during formation and especially during solvent development following exposure to an electron beam. As crystallinity accentuates cracking owing to swelling stresses at the crystalline–amorphous interface, the morphology of various poly(olefin sulfones) was studies by light scattering. Materials investigated were solvent-cast and hot-pressed films of poly(butene-1 sulfone) (PBS), poly(cyclopentene sulfone) (PCPS), poly(bicycloheptene sulfone) (PBCHS), and two terpolymers of poly(cyclopentene sulfone–co–butene-1 sulfone), in which the molar ratios of cyclopentene to butene-1 were 50/50 (TP1) and 70/30 (TP2). All hot-pressed samples showed scattering patterns characteristic of randomly oriented rod-like superstructures 8–10 μm in length. Among the solvent-cast films, however, only PBS and TP2 samples scattered light indicative of crystallinity. Scattering from these samples were analyzed in terms of “random orientation fluctuation” light scattering theory. Correlation distances of 1.7 and 1.5 μm for the PBS and TP2, respectively, were obtained. The solvent-cast crystalline films (PBS and TP2) had a tendency to crack during dissolution as did the amorphous films of PCPS and PBCHS, indicating that cracking depends on the glass temperature as well as crystallinity. Only the amorphous terpolymer TP1 did not crack, presumably owing to its relatively low glass temperature effected by the butene-1 moiety.     

裂解碳四深加工与资源优化

中国石化天津石化公司乙烯厂裂解碳四深加工采用加氢后生产甲基叔丁基醚(MTBE)和1-丁烯的方案，开车以来由于丁二烯价格居高不下而l-丁烯价格下滑，效益并未达到理想状况。通过对各种原料组成比较，考虑资源综合利用情况建议使用丁二烯装置抽余碳四替代裂解碳四，达到资源优化，效益提升的目的。     

Effect of thermal treatment on solution grown crystals of isotactic propylene/butene-1 copolymers

The annealing behaviour of solution grown crystals of isotactic propylene butene-1 copolymers is studied in detail. Modifications in both position and number of the d.s.c. peaks in the thermograms of single crystal aggregates as a function of the annealing temperature, are observed and correlated with the presence of different crystalline phases. For all samples a maximum is observed when the overall apparent enthalpy of fusion is reported against the annealing temperature. The annealing temperature corresponding to the maximum is a function of the copolymer composition. The diagram is characterized by a minimum corresponding to a percentage of about 43% by wt in butene-1. The long spacing of crystal aggregates is a function of the annealing temperature. For some samples the long spacing has been correlated with the melting temperature of the crystalline phases and the equilibrium melting point calculated. For copolymer samples at high propylene content the examination of the wide-angle X-ray diffraction patterns leads to the conclusion that a certain number of butene-1 units, incorporated during the crystallization, as defects in the crystalline lattice of polypropylene, following the annealing process, are ejected in the amorphous phase.     

在Mo-Bi-Ce/SiO_2催化剂上丁烯-2氧化脱氢的内扩散影响

用玻璃流动外循环无梯度反应器研究了Mo—Bi—Ce/SiO_2催化剂上丁烯-2氧化脱氢的内扩散影响.确定了催化剂的有效因子,多孔催化剂的有效因子随反应温度的升高而减小.在内扩散区域的反应活化能为丁烯-2扩散活化能、动力学区域反应活化能的算术平均值.在内扩散区域的丁烯氧化脱氢生成丁二烯的选择性用经验式描述.