在役柴油加氢装置HAZOP分析技术

柴油加氢装置属甲类火灾危险生产装置,为了保障其安全生产,实现事故早期预防,对其进行风险分析和安全评价势在必行.HAZOP分析方法是流程工业广泛使用的一种危险辨识和分析方法,具有较好的系统性和完备性.首先介绍了HAZOP分析方法的由来及应用情况,其次分析了在役装置HAZOP分析的难点,并提出了相应的建议,然后详述了在役装置HAZOP方法的分析流程.最后以中石油某石化公司在役柴油加氢装置为例进行了HAZOP分析,辨识出可能存在的安全隐患和潜在危险,对较高风险提出了必要的安全保护措施和合理的改进建议.结果表明,HAZOP分析是提高在役装置安全性的一种有效手段,其结果为装置安全管理提供了可靠的依据.     

厌氧迁移式污泥床反应器的水力特性研究

采用脉冲示踪法以NH4Cl作示踪剂,通过其在反应器中的停留时间分布来研究厌氧迁移式污泥床反应器(AMBR)的水力特性。反应器的结构决定了反应器的流态,从而控制着可能达到的处理效率。为优化设计反应器结构研究了反应器的构型、导流板与器壁间距对水力特性的影响。研究发现,反应器的流态介于推流式和完全混合式之间,带有导流板的反应器推流程度更大一些,而底部有孔的反应器推流程度弱,反应器的水力死区较小,均小于20%;导流板与器壁间距为8 mm时最佳。     

Effects of La,Ce on nitrogen removal in sequencing batch reactor

Batch experiments were conducted to study the short-term biological effects of rare earth ions (La³⁺, Ce³⁺) and their mixture on the nitrogen removal in a sequencing batch reactor (SBR). The data showed that higher NH⁺₄―N removal rate, total inorganic nitrogen removal efficiency, and denitrification efficiency were achieved at lower concentrations of rare earth elements (REEs) (<1mg/L). In the first hour of the aeration stage of SBR, the presence of REEs increased the total inorganic nitrogen removal efficiency and NH⁺₄―N removal efficiency by 15.7% and 10%―15%, respectively. When the concentrations of REEs were higher than 1mg/L, the total inorganic nitrogen removal efficiency decreased, and nitrate was found to accumulate in the effluent. When the concentrations of REEs was up to 50.0mg/L, the total inorganic nitrogen removal efficiency was less than 30% of the control efficiency with a high level of nitrate. Lower concentrations of REEs were found to accelerate the nitrogen conversion and removal in SBR.     

On the operator action analysis to reduce operational risk in research reactors

Human errors during operation and the resulting increase in operational risk are major concerns for nuclear reactors, just as they are for all industries. Additionally, human reliability analysis together with probabilistic risk analysis is a key element in reducing operational risk. The purpose of this paper is to analyze human reliability using appropriate methods for the probabilistic representation and calculation of human error to be used alongside probabilistic risk analysis in order to reduce the operational risk of the reactor operation. We present a technique for human error rate prediction and standardized plant analysis risk. Human reliability methods have been utilized to quantify different categories of human errors, which have been applied extensively to nuclear power plants. The Tehran research reactor is selected here as a case study, and after consultation with reactor operators and engineers human errors have been identified and adequate performance shaping factors assigned in order to calculate accurate probabilities of human failure.     

A cost effective method for decentralized sewage treatment

The aim of this research was to upgrade the performance of a conventional septic tank (CST) for on-site treatment of sewage with negligible costs. Although CST is known as an inexpensive pre-treatment system, a complementary treatment is required to reuse its output effluent. In this work, the quality of treated wastewater reached to the standard level for irrigation by the innovational changes made in the structure of CST for converting it into an advanced septic reactor (ASR). The modification consists adding some pipe and trays without using any mechanical or electrical equipment.ASR was operated at ambient temperatures in laboratory and pilot-scale. The effects of up-flow velocities (V_up) of 0.4, 0.5, 0.7, 1 and 1.5 m/h and hydraulic retention times (HRT) of 36, 24 and 12 h on the ASR treatment performance were studied.For optimum V_up of 1 m/h and HRT of 24 h and biomass specific methanogenic activity (SMA) of 0.31 mg COD/g VSS d the maximum removal of chemical oxygen demand (COD), biochemical oxygen demand (BOD5) and total suspended solids (TSS) were 86.2%, 79.4% and 95%, respectively.The results showed that ASR is an appropriate alternative for CST for sewage on-site treatment by a low cost modification.     

PTA锻焊反应器的制造

本文对PTA装置上的大型铬钼钢锻焊反应器,在制造过程中的几个关键技术进行了介绍：控制材料的化学成分提高铬钼钢材料的抗回火脆化能力;采用先进的冶炼工艺和锻造技术保证大型锻件的质量;优化铬钼钢封头正火热处理中的冷却工艺来保证材料的性能指标;采用合理的焊接工艺,既保证了厚壁环焊缝的焊接质量,又降低了制造成本;优化堆焊工艺,保证了反应器内壁的堆焊质量;正确选择热处理规范,对铬钼钢压力容器至关重要。     

废旧线路板中主要有价金属的生物反应器浸出研究

为探讨可供实际生物浸出应用的反应器规模废旧线路板中有价金属浸出特性和工艺条件,通过设计序批式生物浸出反应器,采用分离到的氧化亚铁硫杆菌Z1作为菌种资源,在考察废旧线路板中有价金属的浸出特性的基础上,确定了反应器运行的最佳工艺条件.结果表明,反应器运行的最佳工艺条件为曝气量1L/min、停留时间30h、搅拌速率300r/min以及粉末投加量12g/L.在此条件下,经过101h可以浸出90.24%的铜.同时,经197h的浸出,可以溶出93.06%的镁、92.00%的锌、85.59%的铝和64.51%的镍.因此,生物浸出反应器能有效回收废旧线路板中的有价金属,为该技术的实际应用提供了实验证据.     

控制ORP实现连续流反应器部分亚硝化稳定运行

利用ORP在线监控设备,研究了控制ORP值实现连续流部分亚硝化反应器稳定运行的可行性,并使出水水质满足厌氧氨氧化需求.结果表明,在亚硝氮与氨氮比值、温度和pH值恒定的条件下,反应器内ORP值波动主要由于DO浓度波动引起.在稳定的亚硝化系统中,当ORP值大于250mV左右时,反应器出水亚硝氮与氨氮比值大于2.1;当ORP值控制在150mV左右时,反应器出水亚硝氮与氨氮比值稳定在1.2~1.3之间.ORP值控制在120mV时,反应器出水亚硝氮与氨氮浓度比值为0.9~1.06.将ORP值控制在150mV时,随着进水氨氮浓度由300mg/L提高至813mg/L,反应器出水亚硝氮与氨氮比值基本维持在1.1~1.3之间.但随之增加的游离氨浓度易导致亚硝化菌活性抑制.因此,在低氧环境下ORP作为连续流部分亚硝化反应器亚硝化程度的控制指标,其灵敏度和精度明显优于DO监测设备.     

基于HPR在线监测控制SBR曝气历时实现短程脱氮

应用新型自动呼吸-滴定测量仪在线测量pH值、HPR等信号,进行了在SBR内实现短程脱氮的研究.采用SBR处理人工合成废水,COD和NH4+-N浓度分别为360,40mg/L,温度稳定在20℃,DO低于2mg/L,基于HPR在线监测控制SBR曝气历时.运行约60d后,亚硝酸盐积累率达到88%,COD和NH4+-N去除率均在90%以上,稳定实现了短程硝化反硝化.应用HPR估计硝化过程的NH4+-N浓度发现,NH4+-N实测值与基于HPR的计算值间存在良好的线性关系,相关系数为0.9722;计算值整体低于实测值,主要是由曝气初期的滴定启动滞后所致.     

HABR系统实现固相异养与单质硫自养集成反硝化试验

采用连续流运行方式,将含NO₃--N的原水依次通过HABR(复合式厌氧折流板反应器)内添加木屑(第1系统)和硫磺颗粒(第2系统)的2个系统,在温度为(25±1)℃的条件下,将NO₃--N容积负荷由72g/(m3·d)逐渐提高至80和96g/(m3·d),在不需投加传统型外加碳源的条件下实现了固相异养与单质硫自养的集成反硝化. 结果表明:进水NO₃--N容积负荷为96g/(m3·d)时,系统NO₃--N总去除率达到99.0％,第1系统和第2系统对NO₃--N的去除率贡献各为50.0％;系统出水ρ(COD_Mn)为5.74～10.05mg/L,ρ(SO₄2-)为405～870mg/L,并且没有NH₄+-N和NO₂--N的积累. 第1系统产生的碱度能部分中和第2系统内产生的酸,进水、第1系统、第2系统出水pH分别为7.5、7.5～7.6、6.5～7.2,使硫自养反硝化系统呈现出较强的pH平衡能力,不需外加石灰石调节碱度即可为反硝化细菌提供较适宜的中性生存环境. 系统在pH平衡能力和NO₃--N去除效果2个方面均表现出良好的协同作用,并且通过集成反硝化作用弥补了2个系统单独运行时反硝化过程效率低的缺点,较传统异养型生物反硝化降低了运行成本.