Tempurung kelapa dapat di tingkatkan nilai ekonominya dengan dijadikan sebagai karbon aktif. Sebelum dijadikan karbon aktif, tempurung kelapa dijadikan arang supaya mempunyai sifat lebih baik daripada bahan dasarnya. Karbon aktif merupakan arang yang telah dipadatkan melalui proses aktivasi, sehingga memiliki sifat daya serap yang lebih baik. Proses pembuatan karbon aktif melalui proses pirolisis yang dilanjutkan dengan proses aktivasi mampu memperbesar pori-pori pada arang tersebut sehingga meningkatkan daya serap. Ada beberapa macam teknologi aktivasi diantaranya aktivasi fisika dan aktivasi kimia. Studi literatur ini bertujuan untuk mengetahui teknologi aktivasi fisika beserta kelebihan dan kekurangannya, sehingga bisa menjadi acuan dalam pemilihan proses di pabrik aktivasi karbon. Aktivasi fisika merupakan proses aktivasi dengan cara memutuskan ikatan karbon dari senyawa organik pada suhu tinggi dan bantuan CO2 dan uap. Gas-gas tersebut berfungsi untuk memperluas struktur pori-pori arang sehingga meningkatkan luas permukaannya, menghilangkan substansi yang mudah menguap, serta menghilangkan tar atau hidrokarbon pengotor pada arang. Aktivasi fisika memiliki kelebihan antara lain tidak menggunakan bahan kimia, biaya pembuatannya yang relatif lebih murah, waktu proses relatif lebih singkat dan yield arang yang dihasilkan lebih besar. Aktivasi fisika juga memiliki beberapa kekurangan seperti struktur pori arang yang dihasilkan kurang baik dan dalam prosesnya memerlukan suhu tinggi.

Carbon or charcoal can be made from biomass or cellulose-containing materials such as coconut shells or candlenut shells using a thermal process. One of the thermal process is pyrolysis, which in this process, the material is converted to carbon. The results of pyrolysis are in the form of three types of products namely solids (charcoal / carbon), gas (fuel gas) and liquid (bio-oil). Other products are gases such as carbon dioxide (CO2), methane (CH4) and some gases that have small contents. In general, the pyrolysis process takes place at temperatures above 300 ° C within 4-7 hours. Carbonized carbon or pyrolysis does not have a large adsorption capacity because the pore structure does not develop, so it is need activation process. One way to activate carbon is chemical activation. There is a need to know the best material for activating carbon through chemical process. This article aims to discuss the advantages and disadvantages of various types of chemical activation and to determine the promising chemical for activation. From various methods of chemical activation, the activator that promises to make activated carbon is Phosphoric Acid (H3PO4) because it can produce activated carbon which has a maximum micropore at operating conditions <450oC with a weight percent ratio between activator and sample around 29 - 52%.

Summary The use of renewable energy, such as wind and solar, has significantly increased in the last decade. However, these renewable technologies have the limitation of being intermittent; thus, storing energy in the form of compressed air is a promising option. In compressed air energy storage (CAES), the electrical energy from the power network is transformed into a high‐pressure storage system through a compressor. Then, when the demand for electricity is high, the stored high‐pressure air is used to drive a turbine to generate electricity. The advantages of CAES are its high energy density and quality, and for being environmentally friendly process. In the existing facilities of University of Auckland, New Zealand, air cavern is not available; thus, a high‐pressure tank is used to store the compressed air, which could provide an excellent opportunity for small size applications. There is a limited literature available on the temperature and pressure profiles in a typical high‐pressure tank during charging and discharging processes. Therefore, this research investigates how temperature and pressure inside a high‐pressure tank change during charging and discharging processes. It will provide a better understanding for heat transfer in such system. Furthermore, it will provide the necessary information needed for the designing of an efficient small‐scale CAES. In this work, air is compressed to a maximum pressure of 200 bar and stored into a 2 L tank, which is fully fitted with a pressure transducer and a thermocouple suitable for high‐pressure measurements. The charging and discharging process is theoretically modeled, and the results are compared with the experimental measurements, showing a good agreement. The heat balance on the system is used to validate the steady‐state condition, while dynamic analysis is used to predict the transient change of compressed air and tank wall temperatures. The theoretical modeling is undertaken by solving the differential equations describing the transient change in temperature of both air and tank wall. The results of this study show that air temperature rises from 24°C to 60°C at 100 bar and from approximately 17°C to over 60°C at 200 bar. During discharging process, air temperature drops from ambient to 5°C at starting pressure of 100 bar and to −20°C at starting pressure of 200 bar.

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