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LNG Regasification Vessel Requirement based on DNV Classification Notes No. 16.3

Rifka Aisyah Leave a comment

In previous posts, I shared some of onshore LNG terminal and regasification system. How about offshore LNG regasification system? Does it have any differences with onshore regasification system? In this post, I want to share you practical guidance of offshore regasification vessel from DNV (Det Norske Veritas) Classification Notes No. 16.3. DNV Classification Notes No. 16.3 is applicable for all vessels engages in LNG regasification.

Regasification vessel is intended to regasify LNG then delivered the gas to pipeline gas grid, through a Submerged Turret Buoy or through dedicated export manifold. The Classification Notes specifically explains regasification systems and offloading systems for natural gas through submerged turret buoy offshore or through dedicated gas unloading manifolds. Read More

Water Treatment Plant Capacity Calculation

Rifka Aisyah 1 Comment

In this post, I want to share you how to calculate water treatment plant capacity. I used this term to avoid misunderstanding.

  • Raw water is untreated water coming from water source, such as from wellwater, river, or seawater
  • Utility water is raw water which has been treated and used in plant, such as for personal hygiene (flushing), utility station, cooling tower make up
  • Potable water is sufficiently high quality water which is provided for drinking, cooking, laundry, and safety shower/eye wash
  • Demineralized water is treated water which is usually used as chemical dilution of MDEA or boiler feed water

Water treatment plant capacity calculation begins with demin water demand, potable water demand, utility water demand, and the last is raw water demand. Read More

Typical Content of Feasibility Study

Rifka Aisyah Leave a comment

Many people visited my blog because they searched about feasibility study. I wrote a bit about the topic years ago. I wrote it when I involved in my second feasibility study project, which is bankable feasibility study for ferronickel smelter.

In this post I want to share you typical content of feasibility study. The content actually may be different from one another, depends on the topic. But, after I involved in two previous feasibility projects and current project, I learnt that there is similarity about the structure of the content.

I hope you find this post is useful. Read More

Cargo Emergency Shut Down System in Liquefied Gas Carrier

Rifka Aisyah Leave a comment

I am interested in designing ship-to-shore link and ESD arrangement in LNG vessel. I have involved in about three LNG projects, but I did not design or paid more attention in this field (because all the projects were front-end engineering design). In this post, I want to share you practical information about ESD arrangement as suggested by SIGTTO (Society of International Gas Tanker and Terminal Operators).

Function of Emergency Shut Down System

Function of cargo ESD system is to stop cargo liquid and vapor flow in the event of emergency and to bring the cargo handling system to safe condition. Read More

Book Review: Little Bets, How Breakthrough Ideas Emerge from Small Discoveries

Rifka Aisyah Leave a comment

Weekend is almost over. So let’s begin new week with new insight. Instead of sharing chemical engineering things which may be quite serious, in this post I want to share you a book I read. The title is Little Bets – How Breakthrough Ideas Emerge from Small Discoveries by Peter Sims.

I just read second chapter of the book of ten chapters. So I am quite slow at reading. That is because content in second chapter is really amazing. I highlighted most of the chapter and I internalized the chapter. Problem I always face after reading good book is I forget the content or I don’t know how to behave better based on the book. So, here I write it so it will lessen my forgetfulness.

Title about second chapter is The Growth of Mind-Set. I kept repeating word “growth”, “grow”, “growing” to myself and I visualized is as growing small tree. This chapter is really important for me. Read More

Methane number empirical models

Understanding Methane Number

Rifka Aisyah 1 Comment

In my previous LNG project, we need to supply gas with specified minimum methane number and specified higher heating value.

What is methane number?

It is the measure of resistance of fuel gases to engine knock, known as detonation. Detonation is produced by the auto-ignition of fuel/air mixture ahead of the propagating flame. Detonation must be immediately stopped to avoid increase of wear and tear and engine damage.

If MN is too low, the detonation can reduce engine efficiency and increases the quantity of harmful engine emissions.

MN Calculation

I searched if there is formula for the calculation, but I cannot find it. MN is not gas thermodynamic property, so no equation of state can be used to calculate it. I found there are several online methane number calculators. I tested three of them, Cummin, Wartsilla, and DNV MN calculator, respectively by using LNG Tangguh composition. These are the results.

Read More

Natural Gas Quality Designation Parameters

Rifka Aisyah Leave a comment

When I was working on my second EPC project in Senoro, which was gas processing facility, I read that there are several natural gas quality that shall be complied. In the project, we also had to guarantee that the facilities can process gas from wells so that it met requirement as stated in contract. In this post, I want to share you the quality designation parameters for natural gas. To understand more about this area, please check ISO 13686: Natural Gas – Quality Designation.

Natural gas quality designation parameter
Natural gas quality designation parameter

Read More

Centrifugal Pump Sizing Spreadsheet

Rifka Aisyah 4 Comments

Since past two days, people still celebrate new year, so office activity has not started yet. That means I actually still in holiday too. But I want to update this blog while enjoying my holiday. I cannot (or in a mood) to create full article. So, instead sharing full article, in this post, I want to share you centrifugal pump sizing spreadsheet.

I created pump sizing spreadsheet for my first LNG project. The inspiration came from Pump Sizing Calculation from CheCalc. But I made it better.

I think you should download this spreadsheet because it offers better features that online calculation fro CheCalc. 

  • The spreadsheet is simple. You just input the data in dark yellow highlight
  • Pump sizing is calculated based on rated flow rate. If you want to size based on normal flow rate, input 0 in percentage of rated flow rate
  • Pressure drop components is comprehensive, including pipe loss, fitting loss, and equipment loss
  • Pump data results is comprehensive, including:
    • Suction pressure
    • Discharge pressure
    • Differential pressure
    • Differential head
    • Hydraulic power
    • Pump BHP
    • Rated power (calculated)
    • Rated power (selected) : based on commercial output motor power
    • NPSHA
    • NPSHR
    • Shut in pressure

Stop reading! Start downloading! Hope you find this useful!

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Spreadsheet of Air Compressor and Air Dryer Calculation

Rifka Aisyah 2 Comments

In previous post, I shared about how to calculate capacity of air compressor and air dryer. In this post, I want to share you spreadsheet of the calculation. I made the spreadsheet simple so it can be used easily. You just need to input:

  • Quantity of shutdown valve (SDV)
  • Quantity of control valve (CV)
  • Number of utility station/utility connection
  • Capacity of nitrogen generator

In this spreadsheet, I assume to use dessicant type air dryer, so that you also need to input air loss during regeneration.

This is the screen shoot of example.

Air compressor and air dryer calculation spreadsheet
Air compressor and air dryer calculation spreadsheet

At the beginning, I planned to create online calculator. But I thought it will be difficult for me to prepare it and it also takes time if I prepare it by myself. I hope this spreadsheet is useful!

Compressor calculator

 

Fail-safe position

Fail-Safe Position Selection of Control Valve

Rifka Aisyah 1 Comment

In designing a processing facility, we usually use control valve to manipulates the temperature, pressure, level, or fluid flow rate in process system. The selection of control valve, which is air-to-open or air-to-close, is base on safety consideration. In case of power loss or air failure , control valve should move in safe position (fail-safe).

Fail Position

Fail position is the term used to describe how control valve will react when there is loss of power. I read there are three different fail positions. Read More