Towards Ecological Alternatives in Bearing Lubrication

Hydrogen is the cleanest fuel available because its combustion product is water. The internal combustion engine can, in principle and without significant modifications, run on hydrogen to produce mechanical energy. Regarding the technological solution leading to compact engines, a question to ask is the following: Can combustion engine systems be lubricated with hydrogen? In general, since many applications such as in turbomachines, is it possible to use the surrounding gas as a lubricant? In this paper, journal bearings global parameters are calculated and compared for steady state and dynamic conditions for different gas constituents such as air, pentafluoropropane, helium and hydrogen. Such a bearing may be promising as an ecological alternative to liquid lubrication.

Pengaruh cyclone dan peletakannya terhadap karakteristik gasifikasi dengan menggunakan filter zeolit alam

The gas product from the gasification process contains tar content that is not thermally appropriately degraded before it leaves the reactor; for efficiency, the gasification process must go through filtering or separation using filters and cyclones. This process is essential because of the increase in the gas producer's energy density through the syn-gas filtering and purification process or syn-gas combustion. This study aimed to determine the effect of the cyclone and its placement on the combustion characteristics of gasification using natural zeolite filters, the length of time for the product gas, and how much cyclones and filters can separate tar in updraft type gasification process. In this study, the gasification process uses an updraft type reactor, biomass fuel using rubberwood, filters using natural zeolite media, and adding a coolant (condenser). Testing by varying the addition and placement of the cyclone position. The test results show that the use of cyclone variations does not affect the Temperatur in the reactor. A cyclone's effect using a natural zeolite filter on the characteristics of the combustion product (flame) is very large; namely, the color of the fire is bluish and clean with little smoke and the size of the flame coming out of the burner. The effect of a series of cyclones and natural zeolite filters on the flame duration of Syn-Gas on the burner is ± 44 minutes. Without using the cyclone series, the flame time in the burner only reaches ± 28 minutes. The tar that can be separated by the burner and filter without using a cyclone is 381 grams, and the tar that is separated by the cyclone in the cyclone series after the condenser can accommodate as much as 450 grams.

RISKS OF SUSTAINING THE CURRENT MODEL OF COAL COMBUSTION PRODUCT UTILIZATION ON RUSSIAN THERMAL POWER PLANTS

To assess the probability and potential scale of risks associated with sustaining the current model of coal combustion product (CCP) utilization on Russian thermal power plants.This study adopts a qualitative approach. A panel comprising twenty experts was formed. Experts cores were derived using the Saaty paired comparison matrix.The results of the study indicate that environmental, social and technological risks are among the most significant. The largest scale of effects can be expected from the potential increase in the negative effects from coal ash landfill to ground waters and the distribution of small-sized ash-slag particles as a source of air pollution.Previous studies in Russia have largely dealt with technical aspects of CCP recycling or their potential application areas. However, the issues of the potential aftermath of low CCP utilization volume in Russia have not been properly assessed in prior research.

ANALISIS KANDUNGAN LOGAM BERAT ABU BATUBARA PLTU BANGKO BARAT KAB. MUARA ENIM SUMATERA SELATAN

Coal combustion product (CCP) from Bangko Barat Power Plant is used as landfill material in acidic overburden layers. CCP is categorized as hazardous and toxic waste (PP No.101/2014) from specific sources and is known to contain heavy metals. This study aims to analyze the heavy metal content of coal combustion product from Bangko Barat Power Plant, Muara Enim Regency, South Sumatra Province. Heavy metal content of CCP includes Hg, Cd, Cu, Ag, Ni, Pb, As, Cr, Sn, Zn dan Mn. Heavy metal content analysis to ensure overburden piling by utilizing CCP, either with a long-term safe coating or mixing scheme. The analysis was carried out by using ICP-MS test, XRF test, XRD test, analysis of grain size and grain morphology. Samples of fly ash and bottom ash were categorized as non- hazardous and toxic waste based on the results of the ICP-MS test compared to the values of TK-A, TK-B and TK-C. Heavy metal content that needs attention from coal ash is As (4.4-20 ppm), Cr (26-43 ppm), Cu (30.7-42.6 ppm), Pb (22,2-29,3 ppm), Zn (77.5-128 ppm), Ni (10,6-24,8 ppm) and Mn (144-396 ppm). The content of other heavy metals is relatively low (Hg, Cd, Ag and Sn) and the threshold is not exceeded. Monitoring the quality of runoff water from landfill area using CCP to be controlled so that the heavy metal content does not endanger the health of living things.