Green Ocean Engineering.docx

Tata Tanjung Tamara A10703013 Green Ocean Engineering, Opportunities and Challenges Speaker: Grant Wang (FerMo Corp.) ---------------------------------------------------------------------------------------------------------------Depends on Green Technologies and Environment course last week, we known about offshore platform, onshore platform, corossion include opportunities and challenges. We known that energy is a thing that cannot be separated from human life. All human activities on a household scale and industrial scale, of course require energy. In the future, most of the energy used is obtained from burning of fossil fuels. Thus, the oil and gas industries are fairly important industry in the world. Mr. Wang explain us about processes for oil and gas exploitation as shown Figure 1. There are 2 platforms. That is offshore platform and onshore platform. Nevertheless, currently the exploitation process offshore platforms is still rare. This is due to the difficulty of development and maintenance of offshore platforms. Thus, it is considered less economical compared to onshore platforms. The main problem that occurs quite often on the offshore platform is the occurrence of corrosion due to contact between the platform with air and sea water, especially in the splash. This zone is calculated from areas where the structure is submerged in seawater during the highest tide up to the submerged area at the lowest tide. Between the platform and sea water. For this reason, it is necessary to have an economical and effective protection platform from corrosion.

Figure 1. Oil and Gas Facilities[1] Corrosion is a natural process, which converts a refined metal to a more chemically-stable form, such as its oxide, hydroxide, or sulfide. It is the gradual destruction of materials (usually metals) by chemical and/or electrochemical reaction with their environment. Corrosion engineering is the field dedicated to controlling and stopping corrosion [2]. The most difficult corrosion control is control of structures located in corrosive environments such as the sea. On exploitation offshore the structure will continue to be exposed to a corrosive environment. Offshore oil rigs are one of the important oil exploitation structures in production, but corrosion of oil rigs must be done properly so as not to cause harm or loss. The most difficult corrosion control on an

offshore oil rig is in the splash zone. Where corrosion occurs very quickly and needs protection. The control corrosion in the splash zone that can be used is by using coatings using special materials such as Zn-Al and Ni-Cu alloys, but this method has disadvantages. The use of coatings requires more expensive costs because it requires special treatments such as surface cleaning which will also cost more. The use of coatings also cannot be applied to structures that have been installed and need to be repaired. Therefore, cheaper and more efficient corrosion control technology is needed. One alternative solution for corrosion control is Cathodic Protection. It is a technique used to control corrosion of metals by making the metal surface as a cathode of electrochemical cells. Cathodic protection (CP) is a technique used to control the corrosion of a metal surface by making it the cathode of an electrochemical cell [3]. A simple method of protection connects the metal to be protected to a more easily corroded "sacrificial metal" to act as the anode. The sacrificial metal then corrodes instead of the protected metal. For structures such as long pipelines, where passive galvanic cathodic protection is not adequate, an external DC electrical power source is used to provide sufficient current. Based on the electricity source, Cathodic Protection is divided into two methods, namely: 1) Sacrificial Anode System, this method is called sacrificial anode because the system sacrifices more reactive metal (anode) to protect the main metal (cathode). The principle of this method is to create electrochemical cells where two different metals are electrically connected which are planted in natural electrolytes, such as: soil or water, and 2) Impressed-Current Cathodic Protection (ICCP) System. This method requires a DC electric current (unidirectional) from an outside source connected to an anode metal with a cathode metal (protected metal). This ICCP anode system can take the form of tubular bars of various special materials. Such as: high silicon cast iron, graphite, a mixture of metal oxide, platinum and niobium. This method is usually used to protect large facilities. The ICCP method must be connected to a DC electric current, if the electric current is AC it must be connected to a rectifier because the function of this DC power source is to direct the oxidized electrons from the anode to the protected metal so that the metal is not easily oxidized (corrosion) because of losing electrons.

References: [1] “Oil and gas production handbook An introduction to oil and gas production, transport, refining and petrochemical industry.” . [2] Wikipedia, “Corrosion.” [Online]. Available: https://en.wikipedia.org/wiki/Corrosion. [Accessed: 13-Nov-2018]. [3] “Cathodic Protection.” [Online]. Available: https://en.wikipedia.org/wiki/Cathodic_protection. [Accessed: 13-Nov-2018].