Pemilihan Alternatif Bahan Bakar Mesin Pembangkit PLTD Menggunakan Metode Value Engineering

Pusat Listrik Tenaga Diesel (PLTD) adalah pembangkit listrik yang menggunakan mesin diesel berbahan bakar High Speed Diesel (HSD) atau solar. Dengan digunakannya bahan bakar konvensional selain dilihat dari sisi kadar polusi pada gas buang kemungkinan pembangkit ini sulit untuk dioperasikan di masa mendatang dikarenakan persediaan minyak bumi dunia yang semakin menipis. Selain itu pasar minyak dunia yang tidak stabil menjadikan bahan bakar utama PLTD ini semakin mahal. Padahal di sisi lain, PLN dipaksa untuk menjual energi listrik dengan harga yang murah dan ramah lingkungan. Apabila hal ini tidak diantisipasi maka PLN akan mengalami kerugian serta mendapat label sebagai perusahaan yang tidak ramah lingkungan. Saat ini PLTD Namlea dihadapkan terhadap lima pilihan alternatif bahan bakar. Penelitian ini mencoba untuk menganalisa keputusan pemilihan alternatif bahan bakar menggunakan metode Value Engineering sehingga bahan bakar terpilih merupakan alternatif bahan bakar terbaik yang digunakan PLN khususnya PLTD Namlea dalam proses produksi energi listrik. Dari ke lima pilihan alternatif bahan bakar tersebut, alternatif bahan bakar terpilih adalah alternatif ke 4 yaitu Penggunaan Bio Solar (B20) + Thermol D yang memiliki performansi 58.2249387440 dan value 1.13270657 atau lebih unggul dari alternatif awal (Campuran HSD dan Bio Solar) serta terbukti dapat menurunkan biaya pokok produksi sebesar Rp. 54,- per kWh dan subsidi pemerintah sebesar Rp. 1.229,- per kWh dari alternatif awal yang sedang digunakan saat ini.

Emission performance of major ship classes: An estimation based on a new set of emission factors and realistic activity profile data

The maritime sector significantly contributes on the major environmental problems that humanity is being confronted with their consequences. The Greenhouse Gases (GHGs) emitted from the sector, which are responsible for the global phenomenon of climate change, are estimated in 2,89% of total anthropogenic GHGs. Ships are also an important source of local air-quality degradation in coastal areas by emitting major quantities of pollutants such as Nitrogen Oxides (NOx), Sulphur Oxides (SOx) and Particulate Matter (PM). The overall emitted quantities of the sector seem not to be equally allocated to the major ship classes (containers, dry and liquid bulk carriers, cruise ships, ro-ro ships etc.), even though the engine technologies that are being used in these classes are approximately the same (slow speed, medium speed, high speed diesel engines). A factor of differentiation among the ship types is the activity profile. Depending on the ship type, engines (main, auxiliary, boilers) present different power needs and therefore are being operated at different load points which among others are related with the sailing profile (cruising, maneuvering, hoteling), the cargo type and weight conditions (laden, ballast). In this context the target of the present paper is to evaluate the emission performance of the major ship classes. This evaluation is performed by using a new set of engine load-dependent Emission Factors for ships, which have been derived by a statistical analysis of emission rates found in literature, in combination with average activity profiles per ship type as these are found in dedicated shipping inventory databases and in literature. These activity data concern a global scale of consideration. Results aim to highlight the differences and similarities in the emission performance of ship types, enhancing the understanding of policy makers and ship operators, on the principle of tackling pollutants especially at ports, close to cities.

Experimental Analysis of Engine Performance and Exhaust Pollutant on a Single-Cylinder Diesel Engine Operated Using Moringa Oleifera Biodiesel

In this investigation, biodiesel was produced from Moringa oleifera oil through a transesterification process at operating conditions including a reaction temperature of 60 °C, catalyst concentration of 1% wt., reaction time of 2 h, stirring speed of 1000 rpm and methanol to oil ratio of 8.50:1. Biodiesel blends, B10 and B20, were tested in a compression ignition engine, and the performance and emission characteristics were analyzed and compared with high-speed diesel. The engine was operated at full load conditions with engine speeds varying from 1000 rpm to 2400 rpm. All the performance and exhaust pollutants results were collected and analyzed. It was found that MOB10 produced lower BP (7.44%), BSFC (7.51%), and CO2 (7.7%). The MOB10 also reduced smoke opacity (24%) and HC (10.27%). Compared to diesel, MOB10 also increased CO (2.5%) and NOx (9%) emissions.

PEMILIHAN ALTERNATIF BAHAN BAKAR MESIN PEMBANGKIT PLTD MENGGUNAKAN METODE VALUE ENGINEERING

Abstrak Pusat Listrik Tenaga Diesel (PLTD) adalah pembangkit listrik yang menggunakan mesin diesel berbahan bakar High Speed Diesel (HSD) atau solar. Dengan digunakannya bahan bakar konvensional selain dilihat dari sisi kadar polusi pada gas buang kemungkinan pembangkit ini sulit untuk dioperasikan di masa mendatang dikarenakan persediaan minyak bumi dunia yang semakin menipis. Selain itu pasar minyak dunia yang tidak stabil menjadikan bahan bakar utama PLTD ini semakin mahal. Padahal di sisi lain, PLN dipaksa untuk menjual energi listrik dengan harga yang murah dan ramah lingkungan. Apabila hal ini tidak diantisipasi maka PLN akan mengalami kerugian serta mendapat label sebagai perusahaan yang tidak ramah lingkungan. Saat ini PLTD Namlea dihadapkan terhadap lima pilihan alternatif bahan bakar. Penelitian ini mencoba untuk menganalisa keputusan pemilihan alternatif bahan bakar menggunakan metode Value Engineering sehingga bahan bakar terpilih merupakan alternatif bahan bakar terbaik yang digunakan PLN khususnya PLTD Namlea dalam proses produksi energi listrik. Dari ke lima pilihan alternatif bahan bakar tersebut, alternatif bahan bakar terpilih adalah alternatif ke 4 yaitu Penggunaan Bio Solar (B20) + Thermol D yang memiliki performansi 58.2249387440 dan value 1.13270657 atau lebih unggul dari alternatif awal (Campuran HSD dan Bio Solar) serta terbukti dapat menurunkan biaya pokok produksi sebesar Rp. 54,- per kWh dan subsidi pemerintah sebesar Rp. 1.229,- per kWh dari alternatif awal yang sedang digunakan saat ini.

Prognostic Assessment of the Performance Parameters for the Industrial Diesel Engines Operated with Microalgae Oil

A study conducted on the high-speed diesel engine (bore/stroke: 79.5/95.5 mm; 66 kW) running with microalgae oil (MAO100) and diesel fuel (D100) showed that, based on Wibe parameters (m and φz), the difference in numerical values of combustion characteristics was ~10% and, in turn, resulted in close energy efficiency indicators (ηi) for both fuels and the possibility to enhance the NOx-smoke opacity trade-off. A comparative analysis by mathematical modeling of energy and traction characteristics for the universal multi-purpose diesel engine CAT 3512B HB-SC (1200 kW, 1800 min−1) confirmed the earlier assumption: at the regimes of external speed characteristics, the difference in Pme and ηi for MAO100 and D100 did not exceeded 0.7–2.0% and 2–4%, respectively. With the refinement and development of the interim concept, the model led to the prognostic evaluation of the suitability of MAO100 as fuel for the FPT Industrial Cursor 13 engine (353 kW, 6-cylinders, common-rail) family. For the selected value of the indicated efficiency ηi = 0.48–0.49, two different combinations of φz and m parameters (φz = 60–70 degCA, m = 0.5 and φz = 60 degCA, m = 1) may be practically realized to achieve the desirable level of maximum combustion pressure Pmax = 130–150 bar (at α~2.0). When switching from diesel to MAO100, it is expected that the ηi will drop by 2–3%, however, an existing reserve in Pmax that comprises 5–7% will open up room for further optimization of energy efficiency and emission indicators.

Characteristics of injection of diesel fuel, rapeseed oil and their mixtures in diesel engines of various types

The necessity of adapting diesel engines to work on vegetable oils is justified. The possibility of using rapeseed oil and its mixtures with petroleum diesel fuel as motor fuels is considered. Experimental studies of fuel injection of small high-speed diesel engine type MD-6 (1 Ch 8,0/7,5)when using diesel oil and rapeseed oil and computational studies of auto-tractor diesel engine type D-245.12 (1 ChN 11/12,5), working on blends of petroleum diesel fuel and rapeseed oil. When switching autotractor diesel engine from diesel fuel to rapeseed oil in the full-fuel mode, the mass cycle fuel supply increased by 12 %, and in the small-size high-speed diesel engine – by about 27 %. From the point of view of the flow of the working process of these diesel engines, changes in other parameters of the fuel injection process are less significant. Keywords diesel engine; petroleum diesel fuel; vegetable oil; rapeseed oil; high pressure fuel pump; fuel injector; sprayer

USE OF DIESEL MIXED WITH ETHANOL AND ETHYL ACETATE FOR ALTERNATIVE FUEL IN A HIGH-SPEED DIESEL ENGINE

Particulate matters especially particles with less than 2.5 micrometers (PM2.5) are the main cause of severe air pollution problem in Thailand that lead to the mortality risk in cardiovascular disease. Exhaust gas emissions specifically carbon monoxide and black smoke from diesel engines are the essential sources in generating significant amounts of PM2.5. Improving diesel properties by mixing oxygenated additives is one of the alternatives in reducing this pollutant. The main objective of this research is to investigate the performance and emission of a high-speed diesel engine at 3,000 rpm and different loads operated with diesel mixed with 5 to 20% ethanol and 5% ethyl acetate. The results of engine test at 80% load using diesel mixed with 5% of ethanol and ethyl acetate showed a few decreases in fuel properties and engine performance compared with diesel. The release of black smoke was also decreased to 14%. Increasing the mixture of ethanol to more than 5% has led to the decrease in engine performance continuously. The diesel mixed with ethanol at 20% and ethyl acetate at 5% has reduced the carbon monoxide and black smoke to 0.012%vol and 31.53% respectively and accrued the carbon dioxide at 1.25%vol. This is because the diesel mixed with ethanol and ethyl acetate increased the oxygen level to perform complete combustion as compared with diesel. However, the temperature of these exhaust gases was raised to 55oC