Biodiesel is a traditional energy field that can replace low-quality marine fuels for ships and various studies have been conducted. Since the 2000s, Korea has introduced a mandatory supply system of biodiesel for domestic vehicle diesel, gradually raising the blending ratio from 0.5% to 3.5%, and is expected to raise the mandatory blending ratio to about 8.0% by 2030. Therefore, in this study attempted to blend high-quality samples that meet the biodiesel quality standards manufactured by domestic companies with MGO in ratios ranging from 0 to 60%. We utilized a 1-ton combustion chamber to compare and analyze the exhaust gas emissions characteristics. As a result, in the BD60 condition, which represents the maximum range in this study, the O2 increased by approximately 1.5%p, and CO2 tended to decrease by 1.1%p. NOx decreased by approximately 18.2%p from 34.1 ppm to 27.9 ppm. In the case of SOx, a very low concentration of 0.08 ppm was detected under the BD0 condition, and it was undetectable under all other conditions containing biodiesel. This suggests that MGO itself has excellent low-sulfur oil quality and can implement zero SOx through biodiesel mixing. Furthermore the combustion efficiency decreased by approximately 1.91%, from 72% to 70.2%, and the exhaust gas temperature also decreased by about 4.5%p. However despite the lower calorific value of biodiesel compared to MGO, it demonstrated relatively close thermal output per unit content. This indicates sufficient potential for biodiesel to serve as a viable alternative fuel for ships in the future.

This research investigated the preparation of activated carbon derived from Krabok (Irvingia malayana) seed shells to improve the quality of crude glycerol obtained during biodiesel production. The activated carbon was prepared using a dry chemical activation method with NaOH, utilizing an innovative biomass incinerator. The results revealed that the resulting KC/AC-two-step exhibited favorable physicochemical adsorption properties, with a high surface area of 758.72 m2/g and an iodine number of 611.10 mg/g. These values meet the criteria of the industrial product standard for activated carbon No. TIS 900-2004, as specified by the Ministry of Industry in Thailand. Additionally, the adsorption efficiency for methylene blue reached an impressive 99.35 %. This developed activated carbon was then used to improve the quality of crude glycerol obtained from biodiesel production. The experimental results showed that the KC/AC-two-step increased the purity of crude glycerol to 73.61 %. In comparison, commercially available activated carbon (C/AC) resulted in a higher crude glycerol purity of 81.19 %, as analyzed by the GC technique. Additionally, the metal content (Zn, Cu, Fe, Pb, Cd, and Na) in purified glycerol using KC/AC-two-step was below the standards for heavy metals permitted in food and cosmeceuticals by the Food and Drug Administration of Thailand and the European Committee for Food Contact Materials and Articles. As a result, it can be inferred that Krabok seed shells have favorable properties for producing activated carbon suitable as an adsorbent to enhance crude glycerol purity. Furthermore, the improved crude glycerol from this research has potential for various industrial applications.

This study presents the synthesis, characterization, and utilization of marine macroalgae-derived bio-carbon catalysts (BC and KOH-AC) for the efficient conversion of waste cooking oil (WCO) into biodiesel. The biochar (BC) was produced through slow pyrolysis of macroalgal biomass, which was subsequently activated with potassium hydroxide (KOH) to produce a KOH-modified activated carbon (KOH-AC) catalyst. Advanced characterization techniques, including SEM, EDX, XRD, FTIR, and TGA, were used to examine the physicochemical characteristics of the catalysts. The synthesized catalysts were utilized to produce biodiesel from WCO, and the results revealed that the highest biodiesel yields, 98.96%, and 47.54%, were obtained using KOH-AC and BC catalysts, respectively, under optimal reaction conditions of 66 °C temperature, 12.3 M/O molar ratio, 130 min time, and 3.08 wt.% catalyst loading via RSM optimization. The kinetic and thermodynamic parameters, such as k, Ea, ΔH, ΔS, and ΔG, were determined to be 0.0346 min− 1, 43.31 kJ mol− 1, 38.98 kJ mol− 1, − 158.38 J K− 1 mol− 1, and 92.58 kJ mol− 1, respectively. The KOH-AC catalyst was recycled up to five times, with a significant biodiesel yield of 80.37%. The fuel properties of the biodiesel met ASTM (D6751) specifications, ensuring that it has excellent fuel characteristics and can be used as an alternative fuel.

바이오디젤은 중립연료로써 친환경 연료로 알려져 있으며, 육상에서는 일정 비율을 의무 혼합하는 정책을 시행하고 있다. 본 연구에서는 바이오디젤의 선박 연료로써의 사용 가능성을 검증하기 위해 선박용 경유와 바이오디젤의 혼합비율 0 %, 5 %, 10 %, 20 %에 대해 성분 분석, 금속 부식성 실험, 저장 안정성 실험을 수행하였다. 성분 분석은 ISO 8217:2017 기준에 따라 밀도, 동점도, 인화점 등 총 8가지를 평가하였으며, 180일 동안 상온과 가혹 조건(60 ℃)에서 금속 부식성 실험과 저장 안정성 실험을 통해 바이오디젤 신뢰성을 검증 하였다. 연구 결과, 성분 분석은 바이오디젤 모든 혼합비율에서 ISO 8217:2017 기준을 만족하였으며, 바이오디젤 비율에 따라 동점도, 밀 도, 산값은 혼합비율이 높아질수록 높게 나타났으며, 황분은 혼합비율이 높아질수록 낮게 나타났다. 금속 부식성은 탄소강, 철, 알루미늄, 니켈의 경우 부식이 거의 발생하지 않았으나, 구리의 경우 60 ℃ 환경 바이오디젤 20 % 혼합에서 산소가 풍부한 바이오디젤의 영향으로 부식이 발생하였다. 저장 안정성은 모든 바이오디젤 혼합비율을 180일 동안 상온과 가혹 조건에서 저장한 결과, 변색, 슬러지 발생, 연료 분리가 육안으로 확인되지 않았다.

In this study, the effects of fuel injection pressure changed from 45 to 65 MPa on combustion and emission characteristics were investigated in a common rail direct injection (CRDI) diesel engine fueled with diesel and palm oil biodiesel blends. The engine speed and engine load were controlled at constant 1700rpm and 100Nm, respectively. The tested fuel were PBD20 (20 vol.% palm oil biodiesel blended with 80 vol.% diesel fuel). The main and pilot injection timing was fixed at 3.5°CA BTDC and 27°CA BTDC (before top dead center), respectively. The experimental results show that the combustion pressure and heat release rate increased. In addition, the indicated mean effective pressure (IMEP) and maximum combustion pressure increased with an increase of the fuel injection pressure. Hydrocarbon (HC), smoke opacity and carbon monoxide (CO) decreased, but oxides of nitrogen (NOx) emissions increased as fuel injection pressure increased.

We report the rapid single-step flame synthesis of hydrophobic carbon layers (C-layers) on the surface of stainless-steel (SS) substrates using vaporized biodiesel as the fuel. A co-flow canola methyl ester/air diffusion flame is used to generate a hydrophobic monolayer on the surface of the metal substrate upon its insertion into the reaction zone. Carbon deposition on the surface of the SS substrates varies by changing the SS disk’s position in the post-flame, and by varying its exposure time. The thickness and mass of the flame-formed monolayer varied depending on the substrate’s insertion point into the flame. However, the variation of mass did not significantly impact the C-layer’s uniformity or hydrophobicity. We hypothesize that a small “inner-cone” of the biodiesel flame along with a high soot propensity can result in an ideal medium to form uniform hydrophobic C-layers of unique hierarchical surface structure. This is supported by introducing SS substrates in methane/air flames formed using the same co-flow burner. The hydrophobic property of the carbon deposits was quantified by measuring the contact angle of water droplets placed on the film’s surface. A water droplet drop test was conducted on the flame-formed hydrophobic layers to study their wettability property.

This research aims to study the simultaneous extraction and transesterification of Chlorella vulgaris (C. vulgaris) using microwave irradiation with methanol as solvent and potassium hydroxide (KOH) as catalyst. The microwave-assisted insitu transesterification of C. vulgaris is assessed at various ratios of biomass-to-methanol, reaction times, and catalyst concentrations during the centrifugation and evaporation process. Gas chromatography-mass spectrometry (GC-MS) analysis is performed to confirm fatty acid methyl ester (FAME) composition. Biodiesel preparation is carried out by simultaneous extraction and transesterification of microalgae from C. vulgaris. The product is then characterized using Fourier transform infrared spectroscopy (FTIR) and proton nuclear magnetic resonance (1H-NMR); microalgae are observed using scanning electron microscopy (SEM). The highest amount of FAME is obtained at a biomass-to-methanol ratio of 1:12, reaction time of 40 min, and catalyst concentration of 2 wt%. Biodiesel shows conversion to about 77.64% of methyl ester (methyl myristate, methyl palmitoleate, methyl linoleate, methyl oleate, methyl arachidonate, and methyl 5,8,11,14,17-eicosapentanoate).

In recent years, our reality is facing a serious risk of air pollution from transport vehicles. In particular, various exhaust emissions from diesel engines are pointed out as a serious cause of environmental pollution. This study attempted to study the potential of biodiesel as an alternative energy for CRDI diesel engines. When biodiesel 30% was applied, the smoke emission was reduced by 40% at 4000rpm compared to diesel. On the other hand, there was no significant difference in output, torque, and energy consumption. However, NOx emissions tended to increase compared to diesel. The applicability of biodiesel to CRDI diesel engines has been demonstrated for the characteristics of output and smoke emissions.

In this study, we investigated the effects of diesel-palm oil biodiesel-ethanol blends on combustion and emission characteristics in a 4-cylinder common rail direct injection (CRDI) diesel engine at low idling operations. The engine speed and engine load was 750 rpm and 40 Nm, while the main and pilot injection timing was respectively fixed at 2 °CA before top dead center (BTDC) and 20 °CA BTDC. The experimental results showed that the cylinder pressure increased with the increasing of palm oil biodiesel ratio from 20% to 100%. In addition, the peak value of cylinder pressure increased by 4.35% compared with pure diesel fuel when 5 vol.% ethanol oil added to diesel oil. Because the palm oil biodiesel and ethanol are the oxygenated fuel, the oxygen content played an important role in improving combustion. Based on the high oxygen content of biodiesel and ethanol, their mixing with diesel fuel effectively reduced PM emissions but increased NOx slightly, while CO and HC had no significant changes.

바이오디젤은 신재생연료이면서 환경 친화적인 수송용 액상 바이오연료이다. 곤충은 새로운 바이오디젤 원료로 여겨지고 있다. 특히, 동애등에는 높은 지질을 함유하고 있어 재생가능한 바이오디젤 원료이다. 동애등에 유래 바이오디젤은 포화지방산 함량이 높고 다불포화지방산 함량이 낮아 품질이 좋은 바 이오디젤을 만들 수 있다. 동애등에 유래 바이오디젤은 EN 14214의 대부분 품질기준을 만족한다. 동애등에는 기존의 식물성 원료, 미세조류에 비해 지질 수율이 높아 바이오디젤 생산성이 높다. 본 논문에서는 곤충 유래 바이오디젤의 전반적인 생산 방법과 품질 특성에 대해 서술하였다.

한국과 인도네시아를 포함한 대부분의 국가는 온실가스 감축을 위해 바이오디젤 같은 바이오연료 보급에 대한 강력한 정책을 추진하고 있다. 하지만, 바이오디젤 보급 확대를 위해서는 원료 부족 문제를 먼저 해결해야 한다. 본 연구에서는 원료 공급 안정성을 개선하고 바이오디젤 생산 가격을 낮추기 위해 비식용이면서 동시에 단위면적당 생산성이 높은 인도네시아 열대작물(R. Trisperma) 오일의 바이오디젤 생산 가능성을 조사하였다. 수확기간이 다른 두 종류의 오일은 많은 불순물과 높은 유리지방산 함량을 가지고 있어 효율적인 바이오디젤 생산을 위해, 에스테르화 반응과 전이에스테르화 반응을 실시하였다. 오일은 반응을 진행하기 앞서 여과와 수분제거 과정을 통해 반응의 효율을 높이고자 하였다. 에스테르화 반응은 불균질계 산 촉매인 Amberlyst-15를 사용하였으며, 반응 전 오일들의 산가는 각각 41, 17 mg KOH / g 이었으나, 에스테르화 반응 후 3.7, 1.8 mg KOH/g으로 약 90% 이상의 전환율을 보이며 유리지방산 함량 을 2%이하로 감소시켰다. 이후 전이에스테르화 반응은 KOH를 염기 촉매로 사용하여 바이오디젤 합성 실험을 진행하였다. 생성된 바이오디젤은 약 93%의 FAME 함량을 나타냈으며, 총 글리세롤의 함량은 0.43%으로 제품 규격(FAME 96.5%, 총 글리세롤 0.24%)에는 미달되었다. 이는 지방산 조성 분석 결과 일반적으로 관찰되지 않는 특이 지방산인 α-Eleostearic acid가 10.7~33.4% 포함되어 나타나는 특성으로 판단되며, 추가 반응 최적화 및 분리정제 연구 진행으로 연료품질 규격 달성이 필요한 것으로 나타났다. 기존에 활용되지 못하던 비식용 원료로부터 바이오디젤 생산 기술을 확보할 경우 바이오디젤 보급 확대를 위한 안정적 원료 공급에 기여할 것으로 판단된다.

비식용 원료인 Palm Acid Oil, 동물성 폐유지 등은 상대적으로 자유 지방산 함량이 높기 때문에 일반적인 염기 촉매를 이용한 전이에스테르화 반응에 적합하지 않다. 효소 촉매를 이용하면 염기 촉매에서 해결할 수 없는 몇 가지 문제를 해결할 수 있으며, 에너지 소비가 작고, 바이오디젤 부산물인 글리세롤 회수가 쉬우며, 자유 지방산 함량이 높은 트리글리세라이드에 대한 전이에스테르화 반응이 가능하다. 본 연구에서는 고정화 효소 촉매를 이용하여 1 ton/day 용량의 반응기에서 비식용 폐유지를 바이오디젤로 합성하였으며, 반응 공정의 변수를 최적화하였다.

바이오디젤은 동물성 유지, 식물성 유지와 그 부산물 등의 원료를 사용하여 지방산 메틸에스테르 형태로 제조된 연료이며, 석유계 에너지를 대체할 수 있는 바이오연료로 각광받고 있다. 그러나 바이오 디젤은 저장 및 유통 과정에서 불포화 지방산 메틸에스테르가 산화되면서 연료의 품질이 저하되거나 자동차 엔진부품을 부식시키는 등의 문제를 일으킨다. 따라서 본 연구에서는 바이오디젤의 품질과 산화 특성이 산화 안정성에 미치는 영향을 알아보고, 이와 관련된 평가 방법에 대해 기술하였다. 또한 바이오디젤의 산화 안정성 단점을 개선할 수 있는 방안을 고찰하였다.