吸附式天然气储罐充放气过程的试验研究

Experimental study of the ANG storage tank during charge and discharge

关键词:  ANG  活性炭  冷却水  多孔管  螺旋管 

Key words:  adsorbed natural gas(ANG)  activated carbon  cooling water  perforated tube  helical tube

摘要:

为研制替换家庭用LPG储罐的吸附式天然气(ANG)储罐进行了对比试验。针对ANG技术在应用过程中涉及如何管理吸附热效应的问题,选择比表面积为2 074 m²/g的SAC-02椰壳活性炭,容积为1.5 L的柱状钢制压力容器,在15 L/min的充放气流率下,测试并分析了循环换热水管布置形式、循环水温度及充放气方式变化对储罐吸附床中心温度和储罐累积充/放气量的影响。结果 表明,储罐中心在布置螺旋形换热水管后的温度变化幅度比布置U形换热水管时减少约10 ℃,储罐总充/放气量相应增加18%和14%；储罐换热水管循环常温自来水就能有效抑制储罐吸附床的温度波动；选用多孔管充/放气可使储罐中心温度上升/下降的幅度分别减小15 ℃和10 ℃,但会造成储罐总的充放气量下降2%和7%。家庭用ANG储罐可选用自来水冷却/加热吸附床,在选择换热管和充放气时需兼顾其对储罐总充/放气量的影响。 

Abstract:

Comparative experiments were carried out to develop an adsorbed natural gas (ANG) storage tank for replacing a domestically used liquefied petroleum gas (LPG) tank. Coconut shell activated carbon SAC-02 with SBETof 2 074 m²/g was selected as an adsorbent. A cylindrical steel pressure vessel, which was respectively equipped with a helical heat exchanging pipe, a U-shaped pipe and a perforated tube, was used to evaluate the effect of the cooling/heating water and the charge/discharge patterns on temperature fluctuation of the adsorbent bed and the charged/discharged amount of the storage tank. Tests were undertaken at ambient temperature, under pressure of 3.5 MPa and the flow rate 15 L/min of the natural gas. It shows that, about 10 ℃ fluctuation of temperature at the central region of the storage tank has been cut down by circulating the cooling/heating water along the helical pipe instead of the U-shaped pipe, and the total charged/discharged amount of the gas from the vessel has also correspondingly increased by about 18% and 14%, respectively. Charging/discharging the gas through the perforated tube can reduce the temperature fluctuation amplitude about 15 ℃ and 10 ℃, respectively, but the total amount of gas charging /discharging from the vessel has been decreased by 2% and 7%. It suggests that the running water at ambient temperature is an effective medium for managing the thermal effect of a domestically used ANG vessel in the charge/discharge process, and conformable design of the vessel should be undertaken by optimization among the measures of introducing supplemental heat, heat and mass transfer enhancement of the adsorbent as well as the charge/discharge methods.