A technoeconomic analysis of centralised and distributed processes of ammonia dissociation to hydrogen for fuel cell vehicle applications

Ammonia (NH₃) has been proposed as a hydrogen (H₂) carrier for energy services in the carbon-constrained future. This paper presents a technoeconomic feasibility study of using NH₃ as H₂ carrier for fuel cell vehicles (FCVs) applications. Two cases with different scales of anticipated operations: (1) centralised installation (1000 tonnes day⁻¹) and (2) distributed refuelling station (500 kg day⁻¹), were considered. Aspen HYSYS v8.6 was utilised to simulate the processes. The H₂ production cost, internal rate of return, payback period and net present value were examined and compared. The results indicate the centralised H₂ production is both technically and economically feasible while distributed H₂ production, falling foul of economy of scale, is not economically viable. The overall H₂ production cost of the centralised H₂ production can reach as low as USD 5.50 kg⁻¹ H₂ accounting for capital expenditure, operating expenses, and decommissioning costs. The sensitivity analysis shown that the overall H₂ production cost is highly sensitive to NH₃ price and moderately affected by utility price and various corporate tax rates considered.     

Optimization and analysis of a novel hydrogen liquefaction process for circulating hydrogen refrigeration

In industrial engineering, hydrogen is usually transported and stored after being liquefied, which is an energy-intensive process. Aiming to liquefy hydrogen with high efficiency and low consumption, a novel hydrogen liquefaction process based on dual-path hydrogen refrigeration is proposed innovatively and simulated by Aspen HYSYS to determine the key parameters. Taking the specific energy consumption (SEC) as the objective function for the optimization by genetic algorithm (GA), optimum parameters could be obtained. Meanwhile, the single variable method is conducted to analyze the impact of key parameters on process characteristics. Under the premise of complete liquefaction, the SEC, coefficient of performance (COP) and exergy efficiencies (EXE) of the proposed system are 7.041 kWh/kg _LH2, 0.1834, 0.5413, respectively. Compared with the other three hydrogen liquefaction systems simulated under the same conditions, they are decreased by 22.16% and increased by 33.58% and 42.37%, respectively. The results show that the proposed system shows better performance under lower consumption.     

压缩机出口天然气热量的充分利用

压缩机在凝析气加工工艺中起着举足轻重的作用。经压缩机压缩之后的高温气体常被用来与工艺中的低温介质进行热量交换。但实践证明经压缩机出来的气体温度却难以满足工艺要求。为此,本文通过HYSYS软件对现场流程的参数进行模拟,计算出满足工艺需求的最佳参数。并通过对现场流程的改造,使其过程气温度很好的满足工艺的需要。实践证明:此项改造在气田对过程气温度控制方面效果明显,具有很好的借鉴意义。     

三甘醇脱水装置换热网络夹点技术分析

三甘醇（TEG）脱水工艺是目前国内外天然气净化中应用最广泛的脱水工艺。为有效降低装置能耗,应用夹点技术对TEG脱水装置的换热网络进行了优化分析,运用HYSYS流程模拟软件模拟TEG脱水流程,并从模拟工艺数据中提取参与换热的冷、热物流物性数据,应用温-焓图、栅格图和问题表格法等夹点分析技术对TEG脱水流程的换热网络进行分析,找到装置用能的“瓶颈”--冷、热物流传热温差过大,阻碍热量进一步回收。综合分析温-焓图和TEG再生工艺,发现通过提高富TEG溶液换热后温度,可以降低物流传热温差,增加热量回收。对比优化前后天然气TEG脱水装置的工艺流程,HYSYS模拟所得能耗数据表明优化后脱水装置TEG再生器加热负荷降低了39.40％,问题表格法计算优化后贫TEG溶液冷却量减少了156.20 kW。     

HYSYS模拟三甘醇脱水工艺

油气在运输到中央处理站以后需要进一步处理,尤其是原油应该进一步进行脱水、脱酸等工艺。介绍三甘醇脱水流程,并简述了三甘醇脱水工艺过程,在此基础上运用HYSYS进行三甘醇脱水并以某一区块为例进行深刻的剖析,得出相应的结论与方法。对于轻质原油脱水一般只需要两级即可:自由沉降分离、热化学脱水器或电脱水。由于轻质原油轻组分含量高,经过分离脱水后的原油一般需要再通过稳定塔来达到稳定目的。终端原油脱水的基本流程如下:     

加氢裂化装置生产工业白油的模拟改造

采用Aspen HYSYS流程模拟软件对某蜡油加氢裂化装置分馏塔进行流程模拟,分析了该装置生产5号工业白油的可行性,并提出相应的改造方案。结果表明:该装置重柴油产品中260~380 ℃馏分的芳烃质量分数、40 ℃运动黏度和闪点可满足5号工业白油指标要求;仅通过调整操作条件无法生产出合格的5号工业白油,但通过增设柴油蒸汽汽提塔,采用改变或不改变分馏塔馏出口的改造方案,均能生产出合格的5号工业白油。     

粉煤锁斗系统充/泄压过程的HYSYS动态模拟

利用HYSYS软件对粉煤锁斗系统充/泄压过程进行了动态模拟,并对模型进行了验证。充/泄压过程主要物流的流量以及充/泄压时间与设计值吻合。本模型可以为粉煤锁斗系统的阀门选型提供依据,以及对PID参数进行调试,还可以计算粉煤锁斗系统消耗氮气的峰值量、最小量以及平均流量。     

小型天然气膨胀液化工艺模拟及研究

国内油气资源分散、单井产量小,边远地区的油气资源较丰富,可以利用小型液化天然气装置制成LNG后外输,同时小型天然气膨胀液化工艺又是我国LNG研究工作的重点。利用Aspen Hysys软件对N2-CH4膨胀制冷液化流程进行模拟、研究和分析,得出影响该流程的主要参数:制冷剂高压压力、主换热器出口温度、制冷剂氮气含量、天然气进料压力和LNG储存压力对液化率和比功耗的影响。     

利用在线模拟系统定量优化三管伴热水量

利用开发的在线模拟系统三管伴热系统对中国石化江苏油田试采一厂采油九队三管伴热系统的伴热水进行了定量优化。结果显示,通过建立的HYSYS模型和在线模拟系统,合理优化计算,并通过DCS系统调控伴热水量,节省燃气1365m3/d,节水386m3/d。     

利用ASPEN HYSYS软件处理凝析油稳定系统存在的问题

使用化工模拟软件ASPEN HYSYS模拟出凝析油稳定单元工艺和HydroCOM控制系统压缩机流程。先完善模拟软件内的参数,再根据模拟数据优化现场工艺流程,最终实现凝析油稳定单元零放空运行并达到闪蒸气压缩机额定处理量,提高了系统的可靠性、安全性、经济性和环保性。