合成氨厂液氨库安全因素分析及安全措施

以某合成氨厂为例,对该合成氨厂液氨球罐可能发生的各种危险因素采用软件进行计算和分析,有针对性的在设计中提出安全设施和措施。     

PED-01乙苯脱氢催化剂的评价试验

自主开发的PED-01乙苯脱氢催化剂在100 mL等温评价装置上进行了重复试验和稳定性试验,在反应温度620 ℃、空速1.0 h^-1、水蒸汽与乙苯质量比2∶1和常压条件下,催化剂的乙苯平均转化率为79.51%,苯乙烯平均选择性为95.91%,苯乙烯平均收率为76.25%。侧线装置上条件试验和稳定性试验结果表明,PED-01催化剂的乙苯转化率和苯乙烯平均收率均优于进口催化剂,失活速率比进口催化剂慢,具有更好的稳定性。     

依靠技术进步,推进“十二五”期间氮肥和甲醇行业的科学发展——在2011年技术经验交流会上的讲话

"十一五"期间,我国氮肥和甲醇行业的原料结构调整取得了重大进展,特别是大型国产化的对置式多喷嘴、多元料浆、熔渣-非熔渣及水冷壁式水煤浆气化技术和航天炉连续气化技术的开发成功,大大推进了我国氮肥和甲醇工业的现代化进程。"十二五"期间,应充分发挥技术进步作用,优胜劣汰,提高行业整体水平;总结并进一步推广"十一五"节能降耗成果;加强节能技术和大型化装置的开发研究,使我国氮肥工业达到国际先进水平;调整产品结构,肥化并举,建立多层次、多产品的化工生产体系,延伸产品链,提高附加值,提升企业经济效益和竞争力;狠抓污染物减排,提高行业环保水平;加强技术管理,建立现代化企业。"十二五"时期,氮肥及甲醇企业要按照科学发展观的要求,依靠技术进步,加大结构调整的力度,实现氮肥和甲醇工业的科学发展,为我国农业和国民经济发展做出更大贡献。     

Determination of metastable region for sodium acetate

溶液的介稳区是结晶的基础研究之一.利用静态法测定醋酸钠在水中不同温度下的溶解度,同时利用激光散射法测定醋酸钠在不同温度、搅拌速率、降温速率条件下的超溶解度,得到溶解度与超溶解度的曲线从而拟合出醋酸钠在水中溶解度和超溶解度的方程,确定介稳区范围.研究结果表明,醋酸钠的溶解度随着温度的升高而升高.在一定条件下,搅拌速率越大、温度越高、降温速率越快,介稳区宽度越窄.     

Preparation of (0 2 0)-oriented BaTi2O5 thick films and their dielectric responses

Barium dititanate (BaTi₂O₅) thick films were prepared on a Pt-coated Si substrate by laser chemical vapor deposition, and ac electric responses of (0 2 0)-oriented BaTi₂O₅ films were investigated using several equivalent electric circuit models. BaTi₂O₅ films in a single phase were obtained at a Ti/Ba molar ratio (m_Ti/Ba) of 1.72–1.74 and deposition temperature (T_dep) of 908–1065 K as well as m_Ti/Ba = 1.95 and T_dep = 914–953 K. (0 2 0)-oriented BaTi₂O₅ films were obtained at m_Ti/Ba = 1.72–1.74 and T_dep = 989–1051 K. BaTi₂O₅ films had columnar grains, and the deposition rate reached 93 μm h^?1. The maximum relative permittivity of the (0 2 0)-oriented BaTi₂O₅ film prepared at T_dep = 989 K was 653 at 759 K. The model of an equivalent circuit involving a parallel combination of a resistor, a capacitor, and a constant phase element well fitted the frequency dependence of the interrelated ac electrical responses of the impedance, electric modulus, and admittance of (0 2 0)-oriented BaTi₂O₅ films.     

Synthesis and characterization of poly(ethylene glycol)-b-poly(l-histidine)-b-poly(l-lactide) with pH-sensitivity

In this paper, amphiphilic biodegradable methoxy-poly(ethylene glycol)-poly(l-histidine)-poly(l-lactide) (mPEG–PH–PLLA) triblock copolymers with pH sensitivity were synthesized. The properties of mPEG–PH–PLLA triblock copolymers were investigated by GPC, ¹H NMR, DSC, TGA, XRD and polarized optical microscopy. The results showed that the thermal properties of the triblock copolymers varied with the chain length of PH blocks. The glass transition temperatures (Tg) of the triblock copolymers increased with increasing poly(l-histidine) chain length. The morphologies of PLLA crystals changed from spherulite to dendritic crystal. Moreover, the crystallization rate of triblock copolymers was faster than that of PLLA homopolymer. The pH sensitivity of the self-assembled mPEG–PH–PLLA nanoparticles was investigated. The mean diameter and morphology of the nanoparticles were characterized by DLS, AFM and TEM. The results showed that the mean diameter of mPEG₄₅–PH₃₀–PLLA₈₂ nanoparticles in pH = 5.0 was smaller than that in pH = 7.4.     

Simultaneous improvement of thermal conductivity and mechanical properties for mechanically mixed ABS/h-BN composites by using small amounts of hyperbranched polymer additives

Recently, thermal interface materials (TIMs) are in great demands for modern electronics. For mechanically mixed polymer composite TIMs, the thermal conductivity and the mechanical properties are generally lower than expected values due to the sharply increased viscosity and poor filler dispersion. This work shows that addition of a small amount of polyester-based hyperbranched polymer (HBP) avoided the trade-off in mechanically mixed ABS/hexagonal boron nitride (h-BN) composites. After adding 0.5 wt% HBP, the maximum h-BN content in the composites increased from 50 to 60 wt%. The out-of-plane, in-plane thermal conductivity, and tensile strength of ABS/h-BN with 50 wt% h-BN were 0.408, 0.517 W/mK, and 18 MPa, respectively, and were increased to 0.729, 0.847 W/mK, and 32 MPa by adding 0.5 wt% HBP, while 0.972, 1.12 W/mK, and 29.5 MPa were achieved for ABS/h-BN/HBP with 60 wt% h-BN. The morphological and rheological results proved that these enhancements are due to the improved h-BN dispersion by decreasing viscosity of composites during mixing. Theoretical modeling based on the modified effective medium theory confirmed such results and showed that the interfacial thermal resistance also decreased slightly. Thus, this work demonstrates a facile and scalable method for simultaneously improving the thermal conductivity and mechanical properties of thermoplastic-based TIMs.     

Pb-TKX-50燃烧催化剂的合成及热分解性能

以二氯乙二肟、二甲基甲酰胺、叠氮化钠、盐酸羟胺和硝酸铅等为原料,合成了1,1-二羟基-5,5′-联四唑羟胺铅盐(Pb-TKX-50)燃烧催化剂,研究了Pb-TKX-50对推进剂机械感度的影响以及与推进剂组分的相容性;利用差示扫描量热法和热重法研究了Pb-TKX-50在不同升温速率下的热分解过程,计算其表观活化能(E K和E O)和指前因子(A K),得到其热分解动力学参数、热分解机理函数、热爆炸温度和热力学性质。结果表明,在推进剂配方中加入Pb-TKX-50燃烧催化剂,可以改善其撞击感度和摩擦感度,且与推进剂组分的相容性良好;Pb-TKX-50的主峰分解温度相对于TKX-50的主峰分解温度显著提高,说明其热稳定性显著提高。Ozawa法和Kissinger法得到Pb-TKX-50的表观活化能分别为181.45 kJ/mol和182.49 kJ/mol,且热分解过程符合Avrami-Erofeev方程;Pb-TKX-50的自加速分解温度和爆炸临界温度分别为500.53 K和544.33 K,表明其热稳定性良好;Pb-TKX-50催化剂的热分解自由能(ΔG^≠)为158.87 kJ/mol,活化焓(ΔH^≠)为187.03 kJ/mol,活化熵(ΔS≠)为52.98 kJ/mol。     

马齿苋抑菌洗手液的制备研究

制备具有抑菌作用且绿色环保无污染、对皮肤刺激性小的洗手液。本实验采用马齿苋水提取物作为天然抑菌成分制备抑菌洗手液,并考察羟乙基纤维素的浓度对粘度的影响,马齿苋洗手液与市售洗手液起泡性能的比较,马齿苋洗手液皮肤刺激性和马齿苋水提物添加对抑菌效果的影响。本实验制备的洗手液粘度适中,起泡性好,去污力强,皮肤刺激性小,且具有抑菌作用,是一种环境友好型且具有良好发展前景的绿色洗手液。