Evaluasi Kinerja Dehydration Unit Pada Stasiun Pengumpul Gas Lapangan Sungai Gelam PT. Pertamina Ep Asset 1 Field Jambi

Saat ini PT. Pertamina EP Asset 1 field Jambi sedang dalam pengembangan produksi gas alam, hal ini dikarenakanpotensi gas yang telah ditemukan 5 tahun lalu belum dapat diproduksi karena belum ada pihak yang ingin membeli gastersebut. Namun saat ini PLN menyadari penggunaan gas sebagai sumber energi alternatif dalam pengadaan listrikuntuk daerah Jambi. Maka saat ini PT. Pertamina EP Asset 1 field Jambi mulai memproduksi gas alam yang terdapat disungai gelam untuk dijual kepada PLN. Gas yang didapat dari sumur gas di sungai gelam teryata tidak dapat langsungdikirim ke PLN karena masih mengandung impurities, maka dari itu gas alam hasil sumur gas harus diolah telebihdahulu agar bisa memenuhi persyaratan kontrak kerja oleh pihak PLN. Salah satu syarat tersebut kandungan uap airpada gas tidak boleh lebih dari 20 lbs/MMSC. Maka dari itu pada SP Gas lapangan Sungai Gelam terdapat alat yangberfungsi untuk menghilangkan uap air yaitu Dehydration Unit (DHU). Proses penghilangan air terdiri dari beberapatahap mulai dari penyerapan air dengan menggunakan dessicant, drying dan regenerasi. Maka dari itulah diperlukanalat untuk dapat menyerap air yang terkandung di dalam gas alam. Dehydration Unit (DHU) yang digunakan dilapangan Sungai Gelam menggunakan desikan padat dengan jenis molecular sieve. Namun keberadaan alat ini akandievaluasi apakah sesuai atau tidak untuk mengeringkan gas alam di Sungai Gelam sehingga kandungan air dapatmemenuhi persyaratan dari PLN. Evaluasi dilakukan dengan perbandingan antara kandungan uap air pada gassebelum masuk DHU (inlet) dan setelah masuk DHU (outlet) sehingga diketahui berapa besar kemampuan penyerapandari DHU tersebut, serta kemampuan untuk memenuhi kontrak kerja dengan pihak PLN

In-situ growth of nonstoichiometric CrO0.87 and Co3O4 hybrid system for the enhanced electrocatalytic water splitting in alkaline media

The development of electrocatalysts for electrochemical water splitting has received considerable attention in response to the growing demand for renewable energy sources and environmental concerns. In this study, a simple hydrothermal growth approach was developed for the in-situ growth of non-stoichiometric CrO0.87 and Co3O4 hybrid materials. It is apparent that the morphology of the prepared material shows a heterogeneous aggregate of irregularly shaped nanoparticles. Both CrO0.87 and Co3O4 have cubic crystal structures. Its chemical composition was governed by the presence of Co, Cr, and O as its main constituents. For understanding the role CrO0.87 plays in the half-cell oxygen evolution reaction (OER) in alkaline conditions, CrO0.87 was optimized into Co3O4 nanostructures. The hybrid material with the highest concentration of CrO0.87 was found to be highly efficient at driving OER reactions at 255 mV and 20 mA cm−2. The optimized material demonstrated excellent durability for 45 h and a Tafel slope of 56 mV dec−1. Several factors may explain the outstanding performance of CrO0.87 and Co3O4 hybrid materials, including multiple metallic oxidation states, tailored surface properties, fast charge transport, and surface defects. An alternative method is proposed for the preparation of new generations of electrocatalysts for the conversion and storage of energy

Prediction of Corner Columns’ Load Capacity Using Composite Material Analogy

There are numerous reasons for which concrete has become the most widely used construction material in buildings, one of them being its availability in different types, such as fiber-reinforced, lightweight, high strength, conventional and self-compacting concrete. This advantage is specially realized in high-rise building construction, where common construction practice is to use concretes of different types or strength classes in slabs and columns. Columns in such structures are generally made from concrete which is higher in compressive strength than the one used in floors or slabs. This raises issue of selection of concrete strength that should be used for estimating column capacity. Current paper tries to address this issue by testing nine (09) sandwich column specimens under axial loading. The floor concrete portion of the sandwich column was made of normal strength concrete, whereas column portions from comparatively higher strength concrete. Test results show that aspect ratio (h/b) influences the effective concrete strength of such columns. A previously adopted methodology of composite material analogy with some modifications has been found to predict well the capacity of columns where variation in floor and concrete strength is significant

Comparison of Mechanical Properties of Lightweight and Normal Weight Concretes Reinforced with Steel Fibers

Compared to conventional concrete, lightweight concrete is more brittle in nature however, in many situations its application is advantageous due to its lower weight. The associated brittleness issue can be, to some extent, addressed by incorporation of discrete fibers. It is now established that fibers modify some fresh and hardened concrete properties. However, evaluation of those properties for lightweight fiber-reinforced concrete (LWFC) against conventional/normal weight concrete of similar strength class has not been done before. Current study not only discusses the change in these properties for lightweight concrete after the addition of steel fibers, but also presents a comparison of these properties with conventional concrete with and without fibers. Both the lightweight and conventional concrete were reinforced with similar types and quantity of fibers. Hooked end steel fibers were added in the quantities of 0, 20, 40 and 60kg/m3. For similar compressive strength class, results indicate that compared to normal weight fiber-reinforced concrete (NWFC), lightweight fiber-reinforced concrete (LWFC) has better fresh concrete properties, but performs poorly when tested for hardened concrete properties

Nickel-cobalt bimetallic sulfide NiCo2S4nanostructures for a robust hydrogen evolution reaction in acidic media

There are many challenges associated with the fabrication of efficient, inexpensive, durable and very stable nonprecious metal catalysts for the hydrogen evolution reaction (HER). In this study, we have designed a facile strategy by tailoring the concentration of precursors to successfully obtain nickel-cobalt bimetallic sulfide (NiCo2S4) using a simple hydrothermal method. The morphology of the newly prepared NiCo2S4comprised a mixture of microparticles and nanorods, which were few microns in dimension. The crystallinity of the composite sample was found to be excellent with a cubic phase. The sample that contained a higher amount of cobalt compared to nickel and produced single-phase NiCo2S4exhibited considerably improved HER performance. The variation in the salt precursor concentration during the synthesis of a material is a simple methodology to produce a scalable platinum-free catalyst for HER. The advantageous features of the multiple active sites of cobalt in the CN-21 sample as compared to that for pristine CoS and NiS laid the foundation for the provision of abundant active edges for HER. The composite sample produced a current density of 10 mA cm−2at an overpotential of 345 mV. Also, it exhibited a Tafel value of 60 mV dec−1, which predominantly ensured rapid charge transfer kinetics during HER. CN-21 was highly durable and stable for 30 hours. Electrochemical impedance spectroscopy showed that the charge transfer resistance was 21.88 ohms, which further validated the HER polarization curves and Tafel results. CN-21 exhibited a double layer capacitance of 4.69 μF cm−2and a significant electrochemically active surface area of 134.0 cm2, which again supported the robust efficiency for HER. The obtained results reveal that our developed NiCo2S4catalyst has a high density of active edges, and it is a non-noble metal catalyst for the hydrogen evolution reaction. The present findings provide an alternative strategy and an active nonprecious material for the development of energy-related applications

Two step synthesis of TiO2–Co3O4 composite for efficient oxygen evolution reaction

For an active hydrogen gas generation through water dissociation, the sluggish oxygen evolution reaction (OER) kinetics due to large overpotential is a main hindrance. Herein, a simple approach is used to produce composite material based on TiO2/Co3O4 for efficient OER and overpotential is linearly reduced with increasing amount of TiO2. The scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM) investigations reveal the wire like morphology of composite materials, formed by the self-assembly of nanoparticles. The titania nanoparticles were homogenously distributed on the larger Co3O4 nanoparticles. The powder x-ray diffraction revealed a tetragonal phase of TiO2 and the cubic phase of Co3O4 in the composite materials. Composite samples with increasing TiO2 content were obtained (18%, 33%, 41% and 65% wt.). Among the composites, cobalt oxide-titanium oxide with the highest TiO2 content (CT-20) possesses the lowest overpotential for OER with a Tafel slope of 60 mV dec−1 and an exchange current density of 2.98 × 10−3A/cm2. The CT-20 is highly durable for 45 h at different current densities of 10, 20 and 30 mA/cm2. Electrochemical impedance spectroscopy (EIS) confirmed the fast charge transport for the CT-20 sample, which potentially accelerated the OER kinetics. These results based on a two-step methodology for the synthesis of TiO2/Co3O4 material can be useful and interesting for various energy storage and energy conversion systems