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Volume 10 Issue 3
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SUN Xiao, CAI Chunrong, LUO Zhibin, WANG Xiaobo, ZHU Guangtao, PEI Aiguo. Dynamic Simulation and Energy Comsuption Analysis of 70 MPa Hydrogen Refueling Station[J]. SOUTHERN ENERGY CONSTRUCTION, 2023, 10(3): 150-156. doi: 10.16516/j.gedi.issn2095-8676.2023.03.017
Citation: SUN Xiao, CAI Chunrong, LUO Zhibin, WANG Xiaobo, ZHU Guangtao, PEI Aiguo. Dynamic Simulation and Energy Comsuption Analysis of 70 MPa Hydrogen Refueling Station[J]. SOUTHERN ENERGY CONSTRUCTION, 2023, 10(3): 150-156. doi: 10.16516/j.gedi.issn2095-8676.2023.03.017

Dynamic Simulation and Energy Comsuption Analysis of 70 MPa Hydrogen Refueling Station

doi: 10.16516/j.gedi.issn2095-8676.2023.03.017
  • Received Date: 2023-03-19
  • Rev Recd Date: 2023-04-19
  • Available Online: 2023-04-25
  • Publish Date: 2023-05-10
  •   Introduction  Hydrogen refueling station is the key infrastructure for the promotion of hydrogen fuel cell vehicles. 70 MPa hydrogen refueling can significantly improve the endurance and economy of hydrogen fuel cell vehicles. This paper aims to accurately analyze the energy consumption and reduce the operating cost of 70 MPa hydrogen refueling station.   Method  The dynamic thermodynamic model of the hydrogen refueling process was established for the 70 MPa hydrogen refueling station. The law of dynamic pressure and temperature change during single hydrogen refueling process was studied based on the SAE J2601 refueling protocol. The energy consumption composition of single hydrogen refueling, and the energy consumption change of multiple times of hydrogen refueling were analyzed.   Result  The results show that during single hydrogen refueling process, the onboard hydrogen storage cyclinder is refueled in 165 s, the high-pressure hydrogen storage cyclinder is refilled in 295 s, and one hydrogen refueling cycle is completed within 5 min. The energy consumption of hydrogen refueling comes from compressor, intercooler and precooler, among which the energy consumption of the compressor is more than 64%, and the energy consumption of the intercooler is about one third of that of the compressor. The specific energy consumption during single hydrogen refueling process increases from 0.98 kWh/kg to 1.24 kWh/kg as the number of times of hydrogen refueling increases from the first to the twentieth.   Conclusion  The time of single hydrogen refueling process can be shortened by increasing the compressor flow rate. Reducing compressor energy consumption is the key to save energy in hydrogen refueling process. The pressure configuration of the three-stage high-pressure hydrogen storage cyclinder affects many parts of energy consumption. How to allocate the three-stage pressure is worth further study.
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    WANG X J, LIU R. Structure analysis and optimization of high pressure hydrogen cooler in 70 MPa hydrogen refueling station [J]. Chemical engineering & machinery, 2022, 49(2): 302-308. DOI:  10.20031/j.cnki.0254-6094.202202021.
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    GU L L, WU Y M, YIN L K, et al. Status and prospect of process and configuration technology for hydrogen refueling station [J]. Advances in new and renewable energy, 2021, 9(5): 418-425. DOI:  10.3969/j.issn.2095-560X.2021.05.008.
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    CHEN Z L, ZHAO J CH, QU Y H. Process design of hydrogen refueling station [J]. Energy and energy conservation, 2022(5): 12-14+23. DOI:  10.3969/j.issn.2095-0802.2022.05.003.
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    LIU J J, HE H K. The capacity matching design and energy consumption analysis of hydrogen refueling station [J]. Shanghai gas, 2022(3): 1-5, 25. DOI:  10.3969/j.issn.1009-4709.2022.03.001.
    [13] 沈海仁, 安刚, 郑传祥, 等. 复合材料高压储氢气瓶快速充放氢过程中的温度效应研究 [J]. 化工装备技术, 2012, 33(4): 18-21. DOI:  10.3969/j.issn.1007-7251.2012.04.006.

    SHEN H R, AN G, ZHENG C X, et al. Temperature effects of composite high pressure hydrogen storage cylinders in the rapid hydrogen charging and discharging process [J]. Chemical equipment technology, 2012, 33(4): 18-21. DOI:  10.3969/j.issn.1007-7251.2012.04.006.
    [14] 陈珺珺, 朱旺, 高沛, 等. 国内外加氢站预冷装置技术特点比较分析 [J]. 能源研究与管理, 2021(1): 25-29. DOI:  10.16056/j.2096-7705.2021.01.006.

    CHEN J J, ZHU W, GAO P, et al. Research status and prospects of pre-cooling equipment in hydrogen refueling station [J]. Energy research and management, 2021(1): 25-29. DOI:  10.16056/j.2096-7705.2021.01.006.
    [15] SAE. Fueling protocols for light duty gaseous hydrogen surface vehicles: J2601_202005[S]. New York: SAE International, 2020.
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Dynamic Simulation and Energy Comsuption Analysis of 70 MPa Hydrogen Refueling Station

doi: 10.16516/j.gedi.issn2095-8676.2023.03.017

Abstract:   Introduction  Hydrogen refueling station is the key infrastructure for the promotion of hydrogen fuel cell vehicles. 70 MPa hydrogen refueling can significantly improve the endurance and economy of hydrogen fuel cell vehicles. This paper aims to accurately analyze the energy consumption and reduce the operating cost of 70 MPa hydrogen refueling station.   Method  The dynamic thermodynamic model of the hydrogen refueling process was established for the 70 MPa hydrogen refueling station. The law of dynamic pressure and temperature change during single hydrogen refueling process was studied based on the SAE J2601 refueling protocol. The energy consumption composition of single hydrogen refueling, and the energy consumption change of multiple times of hydrogen refueling were analyzed.   Result  The results show that during single hydrogen refueling process, the onboard hydrogen storage cyclinder is refueled in 165 s, the high-pressure hydrogen storage cyclinder is refilled in 295 s, and one hydrogen refueling cycle is completed within 5 min. The energy consumption of hydrogen refueling comes from compressor, intercooler and precooler, among which the energy consumption of the compressor is more than 64%, and the energy consumption of the intercooler is about one third of that of the compressor. The specific energy consumption during single hydrogen refueling process increases from 0.98 kWh/kg to 1.24 kWh/kg as the number of times of hydrogen refueling increases from the first to the twentieth.   Conclusion  The time of single hydrogen refueling process can be shortened by increasing the compressor flow rate. Reducing compressor energy consumption is the key to save energy in hydrogen refueling process. The pressure configuration of the three-stage high-pressure hydrogen storage cyclinder affects many parts of energy consumption. How to allocate the three-stage pressure is worth further study.

SUN Xiao, CAI Chunrong, LUO Zhibin, WANG Xiaobo, ZHU Guangtao, PEI Aiguo. Dynamic Simulation and Energy Comsuption Analysis of 70 MPa Hydrogen Refueling Station[J]. SOUTHERN ENERGY CONSTRUCTION, 2023, 10(3): 150-156. doi: 10.16516/j.gedi.issn2095-8676.2023.03.017
Citation: SUN Xiao, CAI Chunrong, LUO Zhibin, WANG Xiaobo, ZHU Guangtao, PEI Aiguo. Dynamic Simulation and Energy Comsuption Analysis of 70 MPa Hydrogen Refueling Station[J]. SOUTHERN ENERGY CONSTRUCTION, 2023, 10(3): 150-156. doi: 10.16516/j.gedi.issn2095-8676.2023.03.017
    • 氢燃料电池车是促进交通领域碳减排的重要方式之一[1]。加氢站是氢燃料电池车规模化发展的首要基础设施。当前国内加氢站的加氢压力多为35 MPa[2],一些发达国家开发了70 MPa压力等级的车载储氢瓶和加氢站,可将乘用车的续航里程提升到800 km[3]。2022年冬奥举办期间,8座具备70 MPa加氢能力的加氢站投入使用,显著提升了氢能大巴的续航能力和经济性。70 MPa加氢站的推广应用是未来发展趋势[4]

      70 MPa加氢站相较于35 MPa加氢站一方面对关键设备的要求更苛刻导致建设成本更高[5],另一方面运营成本特别是能耗也更高[6]。许多研究者通过对加氢站系统流程和配置优化,以期最大限度地降低总成本[7]。Rothuizen和Rokni[8]研究高压储氢瓶级数对加氢站能耗的影响,结果表明能耗随级数增加而减小,综合考虑设备成本与能耗,最佳级数为3或者4。目前多数加氢站采用三级高压储氢瓶[9]。Xiao等[10]针对三级高压储氢瓶研究其压力配置,结果表明总能耗随高压罐压力的增加近似线性增加,而随着低压级和中压级的增加呈现出凹曲线形状的趋势。为满足70 MPa加氢要求,压力最高的储氢瓶通常选为90 MPa,另外两个储氢瓶的压力则存在多种组合方式,如50 MPa和70 MPa,30 MPa和60 MPa。

      尽管很多研究建立了加氢过程的物理模型,但存在一些不足。有的模型采用过于简化的氢气状态方程[11],这会导致在高压下出现一定偏差;有的模型在能耗分析时仅考虑压缩机能耗和加氢前预冷能耗,未考虑压缩过程的冷却能耗[12];有的模型仅考虑单次加氢,未考虑多次加氢后的能耗变化。

      文章在现有加氢过程物理模型的基础上,建立70 MPa加氢动态模型,考虑加氢过程中压缩机功率、压缩冷却功率和预冷功率;综合分析单次加氢能耗组成以及多次加氢后的能耗变化;为降低70 MPa加氢站运营成本提供参考。

    • 图1为70 MPa加氢站流程示意图。该加氢站采用站外供氢,长管拖车内氢气最高压力20 MPa。氢气从长管拖车吸入压缩机,压缩后的氢气依次注入三级高压储氢瓶。由于压缩机出口压力很大,为避免温度过高,通常采用多级压缩中间冷却的方案,由冷水机组为压缩机提供冷却。充氢温度是影响车载储氢瓶温升的最主要因素之一[13],为避免车载储氢瓶在加氢后温度过高,氢气在加注前要预冷至−40~−33 ℃,由冷冻机组供冷[14]

      Figure 1.  Process diagram of 70 MPa hydrogen refueling station

      假设图1中高压储氢瓶①压力最高,高压储氢瓶③压力最低。加氢过程如下:(1)加氢机收到加氢指令,高压储氢瓶③通过减压阀向加氢机供氢,同时压缩机向高压储氢瓶③补充氢气;(2)当车载储氢瓶压力升高到与高压储氢瓶③相等时,切换为高压储氢瓶②供氢,同时压缩机切换为向高压储氢瓶②补充氢气;(3)当车载储氢瓶压力升高到与高压储氢瓶②相等时,切换为高压储氢瓶①供氢,同时压缩机切换为向高压储氢瓶①补充氢气;(4)车载储氢瓶加满,若高压储氢瓶的压力未恢复至初始值,则压缩机依次向高压储氢瓶①、②、③补充氢气使其恢复至初始压力。

    • 加氢过程必须通过标准化的加氢协议来规范。目前汽车行业采用的是美国汽车工程师协会SAE J2601[15]加氢协议,最新版本是2020年修订版。SAE J2601协议的范围包括水容积在49.7~248.6 L之间,压力等级为35 MPa和70 MPa的车载储氢瓶,以及大于248.6 L的70 MPa车载储氢瓶。

      SAE J2601设定的加氢目标为3 min加满(SOC≥95%),同时加氢过程中车载储氢瓶内的氢气温度不得超过85 °C。为了同时满足加氢时间限制和温度限制,SAE J2601根据储氢瓶的压力等级、预冷温度等级、容量等级、环境温度和加氢前压力,规定了加氢终了压力和平均增压速率。

      表1给出了一个70 MPa车载储氢瓶加氢前后的参数。根据SAE J2601 Table D28,该储氢瓶对应的加氢终了压力为86.8 MPa,平均增压速率为28 MPa/min。质量流量与压力对应,加氢过程中该车载储氢瓶压力和质量流量如图2所示。

      参数水容积/L温度/℃压力/MPa氢气质量/kg
      加氢前14110101.14
      加氢后14110705.74

      Table 1.  Parameters of onboard hydrogen storage cylinder before and after refueling

      Figure 2.  Pressure and mass flow rate during hydrogen refueling[15-16]

    • 压缩机采用五级压缩中间冷却的方式,各级压缩的压比相等。第一级压缩的出口即第一级中间冷却的入口,五级中间冷却的冷量由冷水机组提供,使压缩过程尽可能接近等温压缩。各级压缩功率和中间冷却冷量分别为:

      $$ {\dot W_{{\text{com}}}} = \dfrac{{{{\dot m}_{{\text{com}}}}({h_{{\text{com,in}}}} - {h_{{\text{com,out}}}})}}{{{\eta _{\text{s}}}{\eta _{{\text{el}}}}}} $$ (1)
      $$ {\dot Q_{\text{int} }} = {\dot m_{{\text{com}}}}({h_{{\text{int,in}}}} - {h_{{\text{int,out}}}}) $$ (2)

      式中:

      $\dot W_{\rm{com}}$ ——压缩机电功率(W);

      $\dot m_{\rm{com}}$ ——压缩机质量流量(kg/s);

      hcom,in ——压缩机入口氢气的比焓(J/kg);

      hcom,out ——压缩机出口氢气的比焓(J/kg);

      $ {\eta }_{\mathrm{s}} $ ——绝热效率;

      $ {\eta }_{\mathrm{e}\mathrm{l}} $ ——电效率;

      $\dot Q_{\rm{int}}$ ——中间冷却冷量(W);

      hint,in ——中间冷却入口氢气的比焓(J/kg);

      hint,out ——中间冷却出口氢气的比焓(J/kg)。

      冷水机组电功率为:

      $$ {\dot W_{{\text{int}}}} = {{\left( {\displaystyle \sum\limits_{i = 1}^5 {{{\dot Q}_{{\text{int}}}}} } \right)} \mathord{\left/ {\vphantom {{\left( {\sum\limits_{i = 1}^5 {{{\dot Q}_{{\text{int}}}}} } \right)} {{\text{CO}}{{\text{P}}_{{int} }}}}} \right. } {\varepsilon_{\text{int} }}} $$ (3)

      式中:

      $\dot W_{\rm{int}}$ ——冷水机组电功率(W);

      εint ——冷水机组能效比。

      长管拖车和3个高压储氢瓶的物理模型是一致的。通过质量守恒和能量守恒方程可以确定任一时刻储氢瓶内氢气的密度和比内能,从而可以确定其余的状态参数(温度、压力、比焓等)。储氢瓶的质量守恒方程为:

      $$ {m_{{\text{cyl}}}}(t) = {m_{{\text{cyl}},0}} + \int {({{\dot m}_{{\text{cyl}},{\text{in}}}} - {{\dot m}_{{\text{cyl}},{\text{out}}}})} {\text{d}}t $$ (4)

      式中:

      mcyl ——储氢瓶氢气质量(kg);

      t ——时间(s);

      mcyl,0 ——储氢瓶初始状态氢气质量(kg);

      mcyl,in ——储氢瓶入口氢气质量(kg);

      mcyl,out ——储氢瓶出口氢气质量(kg)。

      相应地,储氢瓶中氢气密度为:

      $$ {\rho _{{\text{cyl}}}}(t) = {m_{{\text{cyl}}}}(t)/{V_{{\text{cyl}}}} $$ (5)

      式中:

      $ {\rho }_{\mathrm{c}\mathrm{y}\mathrm{l}} $ ——储氢瓶氢气密度(kg/m3);

      Vcyl ——储氢瓶体积(m3)。

      储氢瓶的能量守恒方程为:

      $$ \begin{split} &{m_{{\text{cyl}}}}(t){u_{{\text{cyl}}}}(t) = {m_{{\text{cyl}},0}}{u_{{\text{cyl}},0}}+ \int [{{\dot m}_{{\text{cyl}},{\text{in}}}}{h_{{\text{cyl}},{\text{in}}}} -\\& {{\dot m}_{{\text{cyl}},{\text{out}}}}{h_{{\text{cyl}},{\text{out}}}} - H{A_{{\text{cyl}}}}({T_{{\text{cyl}}}} - {T_{{\text{amb}}}})] {\text{d}}t \end{split} $$ (6)

      式中:

      $ {u}_{\mathrm{c}\mathrm{y}\mathrm{l}} $ ——储氢瓶氢气的比内能(J/kg);

      $ {u}_{\mathrm{c}\mathrm{y}\mathrm{l},0} $ ——储氢瓶初始状态氢气的比内能(J/kg);

      H ——对流传热系数[W/(m2·K)];

      Acyl ——储氢瓶表面积(m2);

      Tcyl ——储氢瓶氢气温度(K);

      Tamb ——环境温度(K)。

      高压储氢瓶的氢气流经减压阀的过程为等焓节流,减压阀的入口比焓即储氢瓶出口比焓:

      $$ {h_{{\text{val,out}}}} = {h_{{\text{cyl,out}}}} $$ (7)

      式中:

      hval,out ——减压阀出口氢气的比焓(J/kg);

      hcyl,out ——储氢瓶出口氢气的比焓(J/kg)。

      减压阀后的氢气由于节流后升温,进入预冷换热器冷却至目标加注温度,预冷换热器所需冷量为:

      $$ {\dot Q_{{\text{pre}}}} = {\dot m_{{\text{ref}}}}({h_{{\text{val,out}}}} - {h_{{\text{pre,out}}}}) $$ (8)

      式中:

      $\dot Q_{\rm{pre}}$ ——预冷换热器冷量(W);

      $\dot m_{\rm{ref}}$ ——加注质量流量(kg/s);

      hpre,out——预冷换热器出口氢气的比焓(J/kg)。

      预冷换热器的冷量由冷冻机组提供,冷冻机组电功率为:

      $$ {\dot W_{{\text{pre}}}} = {{{{\dot Q}_{{\text{pre}}}}} \mathord{\left/ {\vphantom {{{{\dot Q}_{{\text{pre}}}}} {{\text{CO}}{{\text{P}}_{{\text{pre}}}}}}} \right. } {\varepsilon_{{\text{pre}}}}} $$ (9)

      式中:

      $\dot W_{\rm{pre}}$ ——冷冻机组电功率(W);

      εpre ——冷冻机组能效比。

      加氢过程的能耗主要由压缩机、冷水机组和冷冻机组3部分组成:

      $$ Q = \int {({{\dot W}_{{\text{com}}}} + {{\dot W}_{{\text{int}}}} + {{\dot W}_{{\text{pre}}}})} {\text{d}}t $$ (10)

      式中:

      Q ——能耗(J)。

    • 氢气的物性通过查询REFPROP物性数据库得到,该物性数据库中的氢气数据来自真实气体状态方程[17],具有很高的准确度。加氢动态模型的求解逻辑为:(1)根据SAE J2601协议确定加氢压力、质量流量、温度,即确定了预冷换热器的出口状态;(2)根据级联高压储氢瓶的质量守恒和能量守恒,计算得到内部氢气的温度、压力、比焓,即确定了减压阀的入口状态和压缩机的出口状态;(3)根据等焓节流确定减压阀出口状态,从而确定了预冷量和冷冻机组能耗;(4)根据长管拖车的质量守恒和能量守恒,计算得到内部氢气的温度、压力、比焓,即确定了压缩机的入口状态;(5)根据压缩机入口压力和出口压力,计算各级压比、功率和需要的冷量,从而确定压缩机能耗和冷水机组能耗。加氢的车载储氢瓶参数见表1,模型输入参数见表2

      参数数值
      氢压缩机质量流量/(kg·h−1) 56[16]
      氢压缩机绝热效率 0.73[16]
      氢压缩机电效率 0.95[18]
      冷水机组能效比 3[19]
      冷冻机组能效比 1.33[20]
      长管拖车最高压力/MPa 20
      长管拖车储氢量/kg 300
      高压储气瓶①最高压力/MPa 90
      高压储气瓶①储氢量/kg 14
      高压储气瓶②最高压力/MPa 70
      高压储气瓶②储氢量/kg 20
      高压储气瓶③最高压力/MPa 50
      高压储气瓶③储氢量/kg 20

      Table 2.  Input parameters of hydrogen refueling model

    • 加氢过程中长管拖车和3个高压储氢瓶的动态压力如图3所示。首先使用压力最低的高压储氢瓶③供氢,直到其压力降低到等于加氢压力(75 s,44.6 MPa),然后切换到下一个压力较高的储氢瓶供氢,以此类推,在165 s完成加氢;然后按照压力由高到低的顺序对3个高压储氢瓶进行补氢,直到295 s完成补氢,一个加氢循环结束。由于单次加氢量较少,长管拖车的压力仅略有降低。单次加氢的时间由车载储氢瓶加氢和高压储氢瓶补氢两部分组成,车载储氢瓶加氢时间由加氢协议确定,若想缩短单次加氢时间,只能从提升压缩机流量入手。

      Figure 3.  Dynamic pressure of hydrogen storage cylinders during hydrogen refueling

      加氢过程中3个高压储氢瓶和减压阀出口温度如图4所示。高压储氢瓶的温度即减压阀入口温度。由于氢气的负焦耳-汤姆孙效应,减压阀的出口温度始终高于入口温度。随着高压储氢瓶的压力下降,减压阀进入口压差减小,减压阀温升也随之减小。当切换至更高压的储氢瓶时,由于减压阀两端压差骤增,温差也同步骤增。因此,减压阀出口温度随时间呈锯齿状。对比图3图4可以发现高压储氢瓶的温度与压力同步变化,当高压储氢瓶被重新装满时,储氢瓶的温度也恢复到与加氢之前相同。

      Figure 4.  Dynamic temperature of hydrogen storage cylinder and pressure relief valve outlet during hydrogen refueling

      加氢过程中压缩机功率、冷水机组功率和冷冻机组的功率与能耗如图5所示。压缩机的功率很大程度上取决于高压储氢瓶,因为它决定了压缩机的出口压力。随着高压储氢瓶中压力的降低,压比和压缩机功率相应降低。当切换到压力更高的储氢瓶供氢时,压缩机也切换到向该储氢瓶补充氢气,因此压缩功率立即增加。车载储氢瓶加氢完成后,压缩机继续向三级高压储氢瓶补充氢气,高压储氢瓶中的压力升高,压缩机功率随之升高。当切换到向更低压的储氢瓶补充氢气时,压缩机功率立即降低。

      Figure 5.  Electric power and energy consumption during hydrogen refueling

      用于压缩机中间冷却的冷水机组功率表现出与压缩机功率类似的特征,冷水机组的功率约为压缩机功率的三分之一。

      用于加氢前预冷的冷冻机组的功率取决于加氢质量流量和预冷前温度(减压阀出口温度),该功率曲线是图2中的质量流量曲线和图4中减压阀出口温度曲线共同作用的结果。加氢初期,尽管减压阀出口温度很高,但质量流量较小,冷冻机组功率也较低。冷冻机组功率有3个峰值,分别出现在46 s、75 s和120 s,其中第一个峰值对应的加氢质量流量即将到达最大值,且减压阀出口温度仍在高位,后两个峰值对应切换高压储氢瓶的时刻。

      由此可见,三级高压储氢瓶的压力直接影响压缩机、冷水机组和冷冻机组的功率。如何配置三级高压使得整个过程功率最低,目前尚无定论,需要进一步研究。

      图5(a)的功率曲线对时间积分可得到能耗曲线(图5(b)),3项能耗之和为总能耗。单次加氢和高压补氢过程中,能耗逐步上升,最终总能耗4.5 kWh,其中压缩机能耗2.9 kWh,冷水机组能耗0.9 kWh,冷冻机组能耗0.7 kWh。压缩机能耗超过64%。单次加氢4.6 kg,折算成单位质量加氢能耗(比能耗)为0.98 kWh/kg。

      上述分析中的单次加氢是长管拖车的第一次加氢,随着加氢次数的增多,长管拖车中的压力逐渐降低,降低导致压缩机输入和输出的压差增大,单次加氢能耗会有所升高。以5 min为一个加氢周期,连续加氢20次,每次加氢的能耗组成如图6所示。随着加氢次数增多,压缩机能耗近似线性升高,冷水机组能耗约为压缩机能耗三分之一,冷冻机组能耗基本不变。随着加氢次数从第1次增加到第20次,单次能耗从4.5 kWh升高到5.7 kWh,比能耗从0.98 kWh/kg升高到1.24 kWh/kg。这个过程中长管拖车的压力从20 MPa降低到13.1 MPa。当长管拖车的压力进一步降低到5 MPa时,单次加氢比能耗将升高到1.96 kWh/kg。

      Figure 6.  Energy consumption of different hydrogen refueling times

    • 文章建立了一个70 MPa加氢站加氢过程的动态热力学模型,基于SAE J2601加注协议研究了单次加氢过程中的压力和温度的动态变化规律,在此基础上分析了单次加氢和多次加氢的能耗,得出以下结论:

      1)车载储氢瓶165 s完成加氢,级联高压储氢瓶295 s完成补氢,5 min内完成一次加氢循环。若想缩短单次加氢时间,可以从提升压缩机流量入手。

      2)加氢能耗由压缩机、冷水机组和冷冻机组能耗组成,其中压缩机能耗超过64%,冷水机组能耗约为压缩机能耗三分之一。

      3)随着加氢次数增多,长管拖车内压力降低,单次加氢能耗升高。长管拖车压力20 MPa时,加氢比能耗为0.98 kWh/kg,长管拖车压力5 MPa时,加氢比能耗为1.96 kWh/kg。可以根据可接受的加氢比能耗确定长管拖车的运行最低压力。

      4)三级高压储氢瓶的压力配置通过影响预冷前温度和压缩机出口压力,进而影响压缩机功率、冷水机组功率和冷冻机组功率。如何对三级压力进行合理配置,需要进一步研究,文章的加氢模型可以作为研究基础。

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