低返混喷射态塔盘在伴生气脱硫工艺中的应用

西北油田高含硫伴生气在采用甲基二乙醇胺(MDEA)溶液脱硫净化过程中存在频繁的拦液冲塔及净化气中H 2S浓度超标等问题。分析结果表明,其主要原因是伴生气体系中重烃含量高导致胺液易发泡及塔板效率低。提出并设计了一种基于喷射态原理的新型逆流低返混喷射态塔盘结构(SDST)。水力学试验结果表明,相比F1浮阀塔盘,SDST压降可降低10%,通量可提高30%,操作弹性基本不变。SDST塔盘在伴生气脱硫过程的工业应用结果表明,SDST塔盘具有良好的抑制发泡性能,可有效解决伴生气脱硫过程的拦液冲塔问题,同时,塔板效率提高10%以上,有效解决了伴生气脱硫过程中因塔板效率低导致的净化气中H 2S浓度超标问题。

喷射态塔盘在气化水煤气洗涤中的应用

在水煤气初步净化流程中,水洗塔设备占据关键地位,水煤气经过水洗塔初步洗涤后,通过塔盘实现气液接触,并完成热质传递过程,对水煤气而言是一个降温、减湿(相变)、除尘的过程,对洗涤水而言是一个升温、包容灰的过程,最终达到出口煤气含灰量降低,塔盘不带水。水洗塔现有鼓泡态塔盘无法满足气化炉高气量运行,其在高负荷情况下除灰效率不足,严重影响了整个大系统的长周期稳定运行。通过将水洗塔塔盘改造为喷射态塔盘,完美解决了在现有设备基础上提升除灰效率的难题。

喷射型单重态氧发生器性能研究

单重态氧发生器作为氧碘化学激光的核心部件,为化学激光器提供化学能。通过对工业喷射器及旋风分离器的研究,结合产生单重态氧的化学反应环境,进行了大量模拟及设计改进工作,研制了一种新型喷射型单重态氧发生器,并进行了相关实验研究。喷射型单重态氧发生器利用喷嘴能够产生比传统发生器类型更多的气液表面,获得足够的反应效率,可以大幅度降低发生器液体使用量,从而减小发生器辅助系统,提高体积效率。为满足O2(1Δ)停留时间短及分离效率高的要求,利用气液两相喷射的高初速度以旋风分离器完成气液分离。新型发生器氯气利用率可达97%～99%,其O2(1Δ)产率为40%～50%。

超细粉体抑爆装置瞬态喷射特征参数

在敞开空间开展了容积为2 L及5 L的超细粉体抑爆装置瞬态喷射参数研究,重点介绍了5种典型装配条件下的喷射性能,并对相关特征参数进行定量分析。结果表明:抑爆剂喷射所形成的超细粉体云幕特性由气体发生器装配结构和膜片开启压力共同决定,但两者之间必须恰当配置,作用在膜片上的能量份额较大时,膜片开启状态恶化,抑爆器腔体聚压不足,抑爆剂二次喷射严重,反之膜片不能正常开启。装配优化后的I型抑爆器在触发后10 ms内腔体聚压达到峰值,膜片破裂后5 ms内抑爆剂全部喷射,喷射动态性能较好,在第1个100 ms内扩散速度达到15 m/s,在第2个100 ms内扩散速度约13 m/s,0~1 000 ms内平均扩散速度约8 m/s,扩散过程较为连续,不存在二次喷射现象,喷射距离可达到7.5 m,抑爆剂质量分布呈渐进增长,产生的超细粉体云幕特征参数优良。Ⅱ型抑爆器两种装配的喷射表明:当抑爆装置中压力上升历程及压力峰值较为接近时,抑爆剂粉体喷射特性无显著差异。上述结论的可重复性得到了数百次喷射实验的验证。

RLPG点火及冷态喷射过程研究

报道了再生式液体发射药火炮 (RLPG)点火及模拟工质冷态喷射过程的实验结果 ,定量测试了燃烧室、贮液室压力曲线。实验表明 ,采用液体阻尼可以有效减弱点火过程中的压力振荡。针对点火喷射过程建立了数学物理模型 ,并进行了相应数值模拟 ,计算值和实验数据吻合较好。

分子筛与钒基SCR催化器瞬态反应特性对比

在发动机试验台上,对比研究了分子筛和钒基选择催化还原(SCR)催化器在真实柴油机排气环境下的稳态与瞬态反应特性,在此基础上进行了ETC瞬态试验,对分子筛SCR催化器还原剂的瞬态喷射策略进行了优化.结果表明:分子筛SCR催化器在250,℃以下的低温区域的NO_x标称转化效率明显优于钒基SCR催化器,但两者的标称转化效率在高温区域相差不大;在相同工况下,分子筛SCR催化器的瞬态氨存储能力大约为钒基SCR催化器的两倍;在ETC瞬态循环下,分子筛SCR催化器的瞬态响应速度更快,ETC瞬态循环的排放性能远远优于钒基SCR催化器;相比于钒基SCR催化器,分子筛SCR催化器在低温区域使用的氨氮比应提高0.05左右,在负荷跃迁区域应采用更小的还原剂喷射延迟.

运用数字粒子图像测速技术测量柴油瞬态喷雾

分析了数字粒子图像测速(DPIV)技术的基本原理,建立了一套柴油喷雾激光测量试验系统,运用DPIV技术对柴油喷雾结构进行了可视化测量,并测量了柴油的瞬态喷雾特性.研究结果表明,燃油喷雾速度随着喷雾时间的推延逐步降低,在喷雾后期喷雾速度降低尤为迅速;柴油瞬态喷雾具有典型的“树枝”状拟序结构;油粒速度沿轴线方向增加,外围油粒速度远小于核心油粒;喷雾与周边空气发生了“卷吸”作用,在喷雾内部形成了复杂的涡旋运动,涡度沿喷雾轴线方向增大.

非稳态单喷口射流控制扩压器内边界层的分离流动

对扩压器内单喷口射流产生的流向涡控制扩压器内部边界层分离流动行为进行了研究。研究的对象是一个扩张角为10°的二维扩压器,扩压器进出口面积比为1∶4.7,入口高度为15 mm。采用数值计算方法研究了当射流出口速度为非稳态时对分离流动的影响。给出了不同时刻,不同截面上的旋涡涡量分布。结果表明,采用非稳态喷射流向涡方法可以在不改变主流流量特性的情况下,有效地减小分离流动区域。

Effect of TiB_2 addition on microstructure of spray-formed Si-30Al composite

An in situ reaction and spray forming technique were employed in the synthesis of 2% TiB2/Si-30Al composite.The formation mechanism of TiB2 particulates was explained based on thermodynamic theory.The modification of the primary Si in the Si-30Al alloy was interpreted in the light of the knowledge of atomic diffusion.The experimental results show that adding 2% TiB2 to the Si-30Al alloy can effectively refine the primary Si.Moreover,the coarsening and growth of primary Si phase in its semi-solid state was retarded effectively due to the existence of the TiB2 particulates.

Microstructure evolution of spray-formed hypereutectic Al-Si alloys in semisolid reheating process

The Al-27%Si alloy was prepared by the spray forming process,and its microstructure evolution during the semisolid reheating process was investigated.The results show that,the primary Si phase coarsens during the reheating process and the coarsening rate increases with the increase of reheating temperature.The eutectic phase is produced in the molten region when quenched in the cold water.The microstructure evolution in the semisolid state can be divided into three stages.The remarkable characteristic of the first stage is only a solid-state phase transformation process.However,the region around the α（Al） matrix gradually melts in the second stage.The primary Si in the liquid phase coarsens obviously,and the eutectic phase is produced in the molten region when the specimens are quenched in cold water.In the last stage,the same thing as that in the second stage happens except that all the α（Al） matrixes are melted.

栅栏堰塔盘的设计

栅栏堰作为一种特殊的溢流堰形式，目前没有一种明确的设计方法。本文提出了以喷射因子和最小溢流强度为设计判据，以栅栏堰为出口堰的设计方法。该方法可以用于低液体负荷喷射态操作时栅栏堰塔盘的设计。经过实践检验，该设计方法能够提高低液体负荷下栅栏堰塔盘的操作性能。

Dynamic effects of high-pressure pulsed water jet in low-permeability coal seams

Mine gas extraction in China is difficult due to the characteristics such as micro-porosity,low-permeability and high adsorption of coal seams.The pulsed mechanismof a high-pressure pulsed water jet was studied through theoretical analysis,experimentand field measurement.The results show that high-pressure pulsed water jet has threedynamic properties.What's more,the three dynamic effects can be found in low-permeabilitycoal seams.A new pulsed water jet with 200-1 000 Hz oscillation frequency andpeak pressure 2.5 times than average pressure was introduced.During bubble collapsing,sound vibration and instantaneous high pressures over 100 MPa enhanced the cuttingability of the high-pressure jet.Through high-pressure pulsed water jet drilling and slotting,the exposure area of coal bodies was greatly enlarged and pressure of the coal seamsrapidly decreased.Therefore,the permeability of coal seams was improved and gas absorptionrate also decreased.Application results show that gas adsorption rate decreasedby 30%-40%and the penetrability coefficient increased 100 times.This proves that high-pressurepulsed water is more efficient than other conventional methods.

Identification and Modeling of Froth to Spray Transition on Sieve Trays

The transition from froth to spray regime on sieve trays was experimentally studied in an air/water simulator with 300mm diameter. It has been found that the regime transition occurs as the clear liquid height is equal to the residual pressure drop on the trays. A convenient and accurate technique was proposed for determination of the regime transition point. Based on analysis of the transition process at a sieve hole, a new formula which can be used to correlate the experimental results was provided.

Mechanism of wet shotcrete interacting with rock in support systems

In order to have a good understanding of the behavior of wet shotcrete as a support element interacting with the rock mass,mechanism of wet shotcrete interacting with rock in support systems was analyzed through theoretical,numerical study and analytical analysis.A new model of distribution of rock stress state after wet shotcrete was applied,which includes shotcrete layer,composite layer,strengthening layer,plastic layer and elastic layer,and a full illustration of the rock mass stress state was given after shotcrete interacting with rock mass.At the same time,numerical analysis with FLAC gives a stress distribution along the monitor line,respectively,at the sidewall and roof of the tunnel.The displacement obviously decreases with the depth of rock,the tangential stress for tunnel supported by shotcrete is lower than that without shotcrete,and radial stress for tunnel supported by shotcrete is higher than that without shotcrete.It has been demonstrated by AIRY'S stress function,which gives a reasonable solution.Finally,the application of wet shotcrete in Jinfeng Gold Mine shows that the displacement of tunnel decreases obviously in sidewall and roof.

The Effect of Secondary Flows on the Starting Pressure for a Second-throat Supersonic Ejector

The effect of the secondary flow on the starting pressure of a second-throat supersonic ejector has been investigated by adapting the height of the secondary flow inlet.The obtained results show that an optimum value of the secondary inlet height exists,and the starting pressure of the ejector becomes a minimum at that condition.Based on the results of the pressure measurements,a qualitative analysis has been made to clarify the flow behavior and the physical meaning of the performance diagram.It appears that the choking phenomenon of the secondary flow plays an important role in the starting process of the ejector.When the secondary inlet height is relatively small,the choked secondary flow and the supersonic primary flow could be employed to protect the static pressure in the suction chamber from being disturbed by the back pressure effect at a certain primary stagnation pressure,which is lower than the starting pressure for the case of the zero-secondary flow.However,as the secondary inlet height increases and exceeds a critical value,the static pressure in the suction chamber rapidly increases,and the starting pressure of the ejector increases accordingly.

The Two-Dimensional Supersonic Flow and Mixing with a Perpendicular Injection in a Scramjet Combustor

A numerical investigation has been performed on supersonic mixing of hydrogen with air in a Scramjet (Supersonic Combustion Ramjet) combustor and its flame holding capability by solving Two-Dimensional full Navier-Stokes equations. The main flow is air entering through a finite width of inlet and gaseous hydrogen is injected perpendicularly from the side wall. An explicit Harten-Yee Non-MUSCL Modified-flux-type TVD scheme has been used to solve the system of equations, and a zero-equation algebraic turbulence model to calculate the eddy viscosity coefficient. In this study the enhancement of mixing and good flame holding capability of a supersonic combustor have been investigated by varying the distance of injector position from left boundary keeping constant the backward-facing step height and other calculation parameters. The results show that the configuration for small distance of injector position has high mixing efficiency but the upstream recirculation can not evolved properly which is an important factor for flame holding capability. On the other hand, the configuration for very long distance has lower mixing efficiency due to lower gradient of hydrogen mass concentration on the top of injector caused by the expansion of side jet in both upstream and downstream of injector. For moderate distance of injector position, large and elongated upstream recirculation can evolve which might be activated as a good flame holder.