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Gas Sweetening using Iron Sponge Process

Iron sponge process is economically applied for gases containing small concentration of hydrogen sulfide (H2S), usually less than 300 ppm, operating from low to moderate pressure in a range of 3.45-34.5 barg (50-500 psig). Iron sponge process cannot be used to remove carbon dioxide.

Iron sponge process is the oldest and still the most widely used batch process for sweetening of natural gas and natural gas liquids. Overall, iron sponge process has the following characteristics which make it still attractive to be applied: simple process, low capital cost, and relatively low chemical (iron oxide) cost. Furthermore, pressure has a relatively little effect on its adsorptive capacity of a gas sweetening agent. Read More

Firefighting Foam Demand Calculations

Firefighting Foam has been widely used as a fire extinguisher for flammable and combustible liquids for many years. It is consisted of premix solution (a ratio of water and foam concentrate) mixed with air. It forms a stable form blanket which spreads above the fuels and adheres to surfaces.

Foam forms a film above the fuel surface and seals vapor. Fire fighting foam concentrate prevents fuel contact with oxygen, resulting in fire suppression. It also has a high cooling effect and will avoid reignition. Read More

Inert Gas Consumption for Tank Blanketing Calculator

In this post I want to share calculator to estimate inert gas consumption for tank blanketing. Please be noted that the result is average inert gas consumption. For peak consumption, please check my previous post.

I think this is the second time I created calculator. I am quite satisfied with the results because I used plugins.

I hope you find this post useful.

Inert Gas Consumption for Tank Blanketing

Inert gas is used to blanket certain fixed-roof tanks for safety. Nitrogen is a common inert gas used for the purpose. In addition to safety of storage tank, the benefit of tank blanketing includes improved product quality and equipment life cycle.

Why nitrogen is commonly used in tank blanketing?

Nitrogen has inert properties, wide availability, and relatively low cost at any economic efficiency. Other gases, such as carbon dioxide or argon, are also sometimes used for certain application.

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Condensate RVP (Reid Vapor Pressure)

In 2014, I have involved in multi-billion dollars EPC project in Indonesia. The project handled gas and condensate. For condensate, it was stated that the quality shall meet certain RVP (Reid Vapor Pressure) value. In this post, I want to share what RVP is.

Definition of RVP (Reid Vapor Pressure)

Stabilized condensate generally has a vapor pressure specification. Its specification is usually identified by its Reid Vapor Pressure (RVP) or True Vapor Pressure (TVP).

Reid Vapor Pressure (RVP) is related to the vapor pressure of a petroleum product, which measures its inherent tendency to evaporate at 100oF with vapor:liquid ratio of 4:1 (ASTM D323). RVP is a function of hydrocarbon’s composition and is independent of operating temperature and pressure. The value of RVP lies below the true vapor pressure.

The higher the RVP, the more quickly the condensate or  oil will vaporize into the air. Read More

Characteristics of Piping Material

In previous post, we learned how select piping material. There are several considerations in selecting piping material, which are service life, code requirement, allowable stresses, design temperature, design pressure, corrosion, and economics. As a continuation of the post, we also need to understand characteristics of piping material. What are important characteristics of piping material?

Let’s find out.


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Piping Material Selection

During engineering projects, I usually face with usual fluid condition. Therefore, the piping material used is usually carbon steel. But this year my team handled fluids with high acidity, so that material selection for piping and equipment are quite challenging.

In this occasion, I want to share a post about piping material selection. The main purpose is to refresh my knowledge about piping material selection I got during 3rd year in college. I hope I find this post useful in my future projects.

For info, this post will be summary of what I read from several resources. I am not a master of piping. But I hope this post will give us a bit insight in how to select piping material as process engineers. Read More

The Difference between Gross Heating Value, High Heating Value, Net Heating Value, and Low Heating Value

One day I found a nice and short article about the difference between terminology used to express heating values: Gross Heating Value (GHV), High Heating Value (HHV), Net Heating Value (NHV), and Low Heating Value (LHV).

As mentioned in my previous post about how to convert high heating value (HHV) to low heating value (LHV), the difference between those terms is if energy used to vaporize water include in the value.

During combustion, fuel react with oxygen molecules to form carbon dioxide, water, and to release heat. The heat released is called heat of combustion. Some of the heat released are used to vaporize existing moisture in the fuel and the water product.

Because all combustion reactions occur at temperatures above water boiling point, both existing water in fuel and water product are in vapor state after combustion. In a bomb calorimeter, the water in vapor state (existing as fuel moisture and water product) is cooled and condensed to room temperature. Therefore, the heat of condensation is recovered. All the heat of combustion are measured by the bomb calorimeter. The total heat of combustion measured by a bomb calorimeter per unit mass is called “high heating value” (HHV) or “gross heating value” (GHV). Read More

Design of Air-Cooled Exchanger (Part 2)

This post is continuation of air-cooled exchanger design (part 1). In this post, I want to share free spreadsheet of air-cooled exchanger design. I used sizing procedures from GPSA engineering data book.

Please differentiate between heat load and motor power. I sometimes found young engineers confused heat load with motor power, especially when listing equipment load list.

I found many resources in internet about how to size air-cooled exchanger. We can size air-cooled exchanger easily by inputting necessary variables. For example, I used Checalc to calculate air-cooled exchanger. But, it is necessary to understand what we do.

The hardest part of sizing air-cooled exchanger by using spreadsheet is so many data to check in charts/graphs. For example, friction factor, physical property factor, and correction factor. I hope we can be patient to handle this.

Please check my spreadsheet about how to size air-cooled exchanger. I hope you find this post useful.

Air Cooled Exchanger

Design of Air-Cooled Exchanger (Part 1)

Air-cooled exchangers are used to cool fluids with ambient air. They should be considered when cooling water is in limited or expensive. Air-cooled exchangers are used for cooling and condensing.

Principle of air-cooled exchanger
Principle of air-cooled exchanger [1]
Air-cooled exchangers consist of banks of finned tubes over which air is blown or drawn by fans mounted below or above the tubes. Air-cooled exchangers are classified as forced draft when the tube section is located on the discharge side of the fan, and as induced draft when the tube section is located on the suction side of the fan. Read More