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Mixture of hydrogen and natural gas HCNG mixing equipment production and refueling experi-ment were performed for supply and product. Hydrogen and CNG in 30 : 70 ratio is mixing of HCNG was per-formed using ratio control. HCNG refueling method was calculated after reading the pressure of tank for full refuel, amount refuel. Both full refuel and amount refuel results mixed ratio 30 : 70 in the error limits of H 2 ±2% met the criterion. HCNG composition analysis result in refueling tank using gas chromatography is satisfying the error limits in refuel tank 30 : 70 ratio were confirmed.Key words : HCNG mixing equipment, refueling, dispenser, mixing ratio, gas chromatography 1) I. 서 론 수송용 연료의 대부분을 수입에 의존하는 국내의 경우 석유계인 수송용 에너지원의 다변화 차원에서 천연가스를 활용하여 석유계 에너지 위기 시 고유가 충격을 흡수할 필요가 있다. 천연가스는 옥탄가가 높아 소형부터 대형 엔진까지 광범위하게 사용될 수 있고 삼원촉매를 사용하는 이론공연비 연소는 물론이고 희박연소만으로도 현 자동차 배기가스 규제 EURO-V의 배기규제를 만족시킬 수 있을 만큼 자동차 † Corresponding author:jslee@kogas.or.kr Copyright ⓒ 2014 by The Korean Institute of Gas

In this study, simulation work of HCNG refueling system was performed. The hydrogen was produced from steam reforming process by natural gas. The conversion of natural gas is increased as SCR is increased. but it was no significant difference more than 3 of SCR and fuel throughput is increased as GHSV is increased. Both conversion and fuel throughput levels was optimized when the 1700h -1 of GHSV. CNG was compressed from low pressure natural gas. For the mixing of H 2 and CNG is mixed with the high pressure con-ditions such as 400bar of H 2 and 250bar of natural gas. Single-stage compression was required more power than multi stage. So, multi stage compression was suggested for high pressure compression. We calculated the intermediate pressure to minimize total required power of compressors. The intermediate pressure for H 2 and natural gas were derived at 61 and 65 bar, respectively.Key words : HCNG, steam reforming, reactor, SCR(steam to carbon ratio), GHSV(gas hourly space veloc-ity), multi-stage compression

A numerical study on the heat and fluid flow has carried out for the design of the steam reforming reactor which consists of six reforming tubes and one burner. Reforming reaction calculation is coupled with the heat and fluid flow one. The burner type in the reforming reactor is chosen through the fluid flow calculation according to different type of burner structure. It is shown that the significant temperature gradient exists in the reforming reactor, affecting the component variation along the length of reforming tube. The component ratio of reforming gas is changed by the variation of SCR and GHSV.

Natural gas through pipeline is supplied to consumers after its pressure gets down compulsorily. The waste pressure energy of this process can be restored by use of turbo expander which can produce electricity. So, turbo expander conducts two functions - pressure reduction and power generation. The power amount is the enthalpy difference between the inlet and outlet states. The five main factors which affect economic profit are facility price, produced power amount, pre-heating amount, electricity cost, and fuel gas cost. Power generation depends mainly on flow amount because inlet and outlet states are fixed. A methodology to estimate economy in irregular flow pattern is proposed and using this way, a case study was carried out.Key words : pressure regulation, waste pressure, turbo expander, power generation, enthalpy-entropy dia-gram, economic evaluation † I. 서 론 화석연료의 고갈에 따른 고유가와 에너지자원 확보의 문제, 그리고 화석연료 소비 시의 CO 2 배출에 따른 기후변화 환경 문제는, 이미 전 세계적인 현안 † 주저자:jmha@kogas.or.kr으로써 그 해결책을 위한 부단한 노력은 경제적 문제일 뿐만 아니라 생존의 문제이기도 하다. 이에 따라 신재생에너지의 개발과 연구노력이 가속화되고 있으며 대규모 플랜트의 운영과정에서의 에너지소비 효율을 향상 시키고, 공정 중의 미활용 에너지를 효과적으로 회수하는 부분도 녹색정책의 일환으로 매우 중요하다 할 수 있다. KIGAS Vol. 16, No. 3, June, 2012(Journal of the Korean Institute of Gas)