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Water Chiller Inspection: My First Experience

Rifka Aisyah Leave a comment

Today, the project manager our EPC project asked me to participate in water chiller inspection in Cileungsi, Bogor, Indonesia. It was my first time. So, I felt a bit excited as well as confused. On that inspection, my role was to inspect the equipment and the technical aspects. I actually did not have any idea about the equipment, except the function.

Simply, we can say water chiller is a refrigeration device. It is used to cool a process fluid. A chiller will use either a vapor compression or absorption cycle to cool.

Type of Industrial Chiller

Figure blow shows type of industrial chiller.

 

Component of Chiller

The basic component of chiller are compressor, evaporator, condenser, and thermostatic expansion valve.

Wastewater Treatment System

Rifka Aisyah 1 Comment

A few weeks ago I got a discussion about wastewater treatment system in our proposed plant. I discussed with one of my colleague. He said, “Let the nature works! Let it process the wastewater by itself”. It sounds weird at the first time. But he’s right and he’s a bit wrong.

He’s right because the natural water in streams, rivers, lakes, and reservoir have a natural waste assimilative capacity to remove solids, organic matter, even toxic chemicals in wastewater. He’s a bit wrong because the process takes a really long time. That’s why we need wastewater treatment system to make it quick (read more in Water and Wastewater Calculation Manual). Read More

Hydrostatic Test for Boiler

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I just got an opportunity to witness hydrostatic test for boilers in my recent EPC project. Hydrostatic test is the most common procedure used to qualify newly manufactured pressure pressure. The purpose is to make sure here is no leak in the boiler.

The procedure was quite simple yet important. Pressure parts shall be subjected to a hydrostatic test pressure which at every point is at least equal to:

1.5 times the MAWP (Maximum Allowable Working Pressure) for ASME section I code.

1.3 times the MAWP for ASME section VIII Div. I code

(The MAWP may be assumed to be the same as the design pressure)

The design pressure of my boilers is 10 barg. When this test applied, the QC engineer increased the pressure of boiler to 10 barg and hold it for 15 minutes. They checked visually the internal of boiler if there’s a leak. Unfortunately, there’s no digital recorder available to record the pressure of boiler during the test. So, we needed to check by our naked eyes the pressure gauge.

After 15 minutes, the increased the pressure to 15 barg at hold it for an hour. After that, they decreased the pressure to 10 barg again, hold it for 15 minutes, then decreased again to 1 barg. The inspection was done visually.

Assessment of Cooling Tower Performance

Rifka Aisyah 3 Comments

Yesterday, I just got an opportunity to inspect some of cooling tower equipment, such as motors, fans, fan stack, low oil level switch, and so on. It was great. I got more understanding about the system, which is very valuable for me as young chemical engineer.

Before I do the inspection, I tried to learn something about cooling tower. I found from this link about how to assess a cooling tower. In this post I want to give you an example of my own cooling tower.

There are several parameters to assess the performance of cooling towers. Note: CT = cooling tower; CW = cooling water Read More

Heat Loss Calculation of Tank Heater

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My recent study was to calculate heat loss in tank heater in order to determine condensate load. It was a pretty simple method. In this post, I provide you the example of my calculation and I hope you find it useful. The problem statement was:

  1. Heat marine fuel oil from 50 to 60 degree C in 5 hours
  2.  Continue to maintain 60 degree C in an insulated tank with a wind velocity 10.08 km/h and an ambient temperature of 27.4 degree C
  3. Tank is 6.8 m diameter and 6.04 m of height
  4. Steam is available at 8 barg

You can find the source of my calculation from this link.

Calculation of tank heater heat loss.

Storage Tank Selection

Rifka Aisyah 1 Comment

In my recent project, there are at least eight liquid storage tanks we need to design and purchase. Although, the design of storage tank is not part of my work (it is a job of mechanical engineers), but I always wonder how people design the tanks. In this post, I want to share to you the results of my desktop study about liquid storage tank selection. Read More

Calculation of Water Spray for Fire Protection of Vertical Vessel

Rifka Aisyah 2 Comments

I just got an assignment from my boss to calculate fire protection of vertical vessel. NFPA 15 (National Fire Protection Association 15) is a standard for water spray fixed system for fire protection.

Definition

As per NFPA 15, water spray refer to the use of water in a form of having a predetermined pattern, particle size, velocity, and density discharged from specially designed nozzle devices. Read More

Condensate Load Calculation

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I just read some pages on Handbook of Chemical Engineering Calculations 2nd edition, written by Nicholas P. Chopey and got interested in calculation of condensate load in order to determine the capacity of steam trap. I will take one example, where the steam indirectly heats a liquid through metallic surface, as in heat exchanger and kettles.

Case I

For example, we have 1892.5 L of water heated in 30 min from 22.2 to 100 oC with 50-psig (344.7-kPa) steam in the jacket of kettle. How much condensate formed?

For normal warm up load, the quantity of condensate can be calculated by the following equation: Read More

IP Codes

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The IP Codes, Ingress Protection Rating, sometimes also interpreted as International Protection Rating, classifies and rates the degree of protection provided against the intrusion of solid objects (including body parts like hands and fingers), dust, accidental contact, and water in mechanical casings and with electrical enclosures.

A two-digit number established by the International Electro Technical Commission, is used to provide an Ingress Protection rating to a piece of electronic equipment or to an enclosure for electronic equipment.

The protection class after EN60529 are indicated by short symbols that consist of the two code letters IP and a code numeral for the amount of the protection.

Example: IP65 (NEMA 4)
The two digits represent different forms of environmental influence:

  •  The first digit represents protection against ingress of solid objects.
  •  The second digit represents protection against ingress of liquids.

The larger the value of each digit, the greater the protection. As an example, a product rated IP54 would be better protected against environmental factors than another similar product rated as IP42.

FactorSedimentationFiltration
Solid size, finex
Solid size, > 150 micronx
Compressible cakesx
Open cakesx
Dry cake requiredx
High filtrate clarityx
Crystal breakage problemsx
Pressure operation
High-temperature operationwill depend on the type of centrifuge usedwill depend on the type of centrifuge used

References:

  1. IP ratings. http://www.mpl.ch/info/IPratings.html
  2. IP code. http://en.wikipedia.org/wiki/IP_Code

Sizing of Expansion Tank for Hot Oil System

Rifka Aisyah 7 Comments

I want to share my experience about sizing of expansion tank especially for thermal oil heater. It is quite simple actually. I will give you an example.

Function of Expansion Tank

The functions of expansion tank are:

  • Serves as the safe outlet for the increase in thermal fluid volume due to thermal expansion
  • Provides a mechanism for venting water, incondensibles, degradation by products and entrained air during start-up and operation

Sizing Expansion Tank

Hot oil system with expansion tank
http://www.thermal-fluid-system.com/Custom-Hot-Oil-System-p164.html

When selecting an expansion tank, the system volume (including the initial fill) of the expansion tank, the operating temperature and the fluid’s coefficient of thermal expansion should all be considered. Because thermal oils expand at different rates, the expansion tank capacity always should be verified against the oil properties prior to filling the system. Read More