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"With the growth of utilizing natural gas all over the world, Liquefied Natural Gas (LNG) has been widely used in the modern era due to its advantages of storage and transportation. When LNG is unloaded in import terminal, in the time of need, the process of returning natural gas into its gaseous form is being done in the regasification unit with different technologies in order to process the gas and then distribute it by pipeline networks to the end users. Choosing the appropriate LNG vaporizer which is both cost effective and suitable to conditions of the location and environment is intended to be evaluated. The framework of this paper is studying of some of the different LNG vaporization methods and comparing their features and properties that each of them has. The goal of this paper is in the first step, comparison of technologies which are Open Rack Vaporizer (ORV), Shell and Tube Vaporizer (STV), and Intermediate Fluid Vaporizer (IFV) and defining the suitable vaporizer to do the simulation as the second step as well as evaluating the economical features of the project. While the Shell and Tube Vaporizer has been chosen, the regasification plant using three different heating medium, propane, steam, and 50/50 mixture of water and glycol has been designed. At the end, the economic evaluation has been done with total capital investment of 62 million dollars in the service life of 10 years. The NPV is calculated 11.33 million dollars and the salvage value is calculated to be 5.2 million dollars. Each heating medium is considered to be effective depending on the locations and conditions."

"Optimalisasi pabrik regasifikasi liqufied natural gas LNG penting dilakukan untuk meminimilasi biaya, khususnya biaya operasional. Oleh karena itu penting untuk memilih desain pabrik regasifikasi LNG dan mendapatkan kondisi operasi yang optimum serta mempertahankan kondisi operasi yang optimum tersebut melalui implementasi model predictive control MPC. Kriteria optimalnya adalah minimumnya jumlah energi yang digunakan dan atau integral of square error ISE. Hasilnya, disain yang optimum adalah menggunakan skema 2 dengan penghematan energi sebesar 40. Sedangkan kondisi operasi yang optimum terjadi jika suhu keluaran vaporizer sebesar 6oC. Untuk mempertahankan kondisi optimum tersebut diperlukan MPC dengan setelan parameter P prediction horizon , M control horizon dan T sampling time sebagai berikut: pengendali tekanan tangki penyimpanan: 90, 2, 1; tekanan produk: 95, 2, 1; suhu vaporizer: 65, 2, 2; dan suhu heater: 35, 6, 5, dengan nilai ISE pada set point tracking masing-masing 0,99, 1792,78, 34,89 dan 7,54, atau peningkatan kinerja pengendalian masing-masing sebesar 4,6 , 63,5 , 3,1 dan 58,2 dibandingkan kinerja pengendali PI. Penghematan energi yang dapat dilakukan pengendali MPC saat terjadi gangguan pada kenaikan suhu air laut 1oC adalah 0,02 MW dan pengendali MPC juga mengurangi error terhadap kualitas produk sebesar 34,25 dibandingkan dengan menggunakan pengendali PI.

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Optimization of liquified natural gas LNG regasification plant is important to minimize costs, especially operational costs. Therefore, it is important to select the LNG regasification plant design and obtain optimum operating conditions while maintaining the optimum operating conditions through the implementation of model predictive control MPC. The optimal criterion is the minimum amount of energy used and or the integral of square error ISE.

As a result, the optimum design is to use scheme 2 with an energy savings of 40 . While the optimum operating conditions occur if the vaporizer output temperature is 6oC. In order to maintain the optimum conditions, MPC is required with parameter setting P prediction horizon, M control horizon and T sampling time as follows tank storage pressure controller 90, 2, 1 product pressure 95, 2, 1 temperature vaporizer 65, 2, 2 and temperature heater 35, 6, 5, with ISE value at set point tracking respectively 0.99, 1792.78, 34.89 and 7.54, or improvement of control performance respectively 4.6, 63.5 , 3.1 and 58.2 compared to PI controller performance.

The energy savings that MPC controllers can make when there is a disturbance in sea temperature rise of 1oC is 0.02 MW and MPC controller also reduces error to product quality by 34.25 compared to the PI controller."