Difference Between Purifier and Clarifier

The key difference between purifier and clarifier is that the purifier consists of a dam ring to create a line of separation between fuel and water whereas the clarifier consists of a sealing ring to prevent the fuel tank from water and dissolved impurities.

Purifier and clarifier are equipment that we use for cleaning or purification of fuel, mainly in case of ships and boats where it is common for fuel to get contaminated with water and other impurities. Though the basic purpose of both a purifier, as well as a clarifier, is the same (cleaning of fuel), there is some difference between purifier and clarifier, which we will be talking about in this article.

CONTENTS

1. Overview and Key Difference
2. What is a Purifier
3. What is a Clarifier
4. Side by Side Comparison – Purifier vs Clarifier in Tabular Form
5. Summary

What is Purifier?

A purifier is a type of centrifugal separator that we can use to separate two liquids with different densities, i.e. water and fuel. A purifier can remove some solid impurities as well. We can modify a centrifuge to make it a purifier.

In that, we should use a second outlet pipe for water discharging process. Typically, untreated fuel oil contains a mixture of oil, solids and water. Hence, a centrifuge separates the fuel oil into three different layers. During this process, a small quantity of the oil remains in the bowl of the centrifuge to form a complete seal at the underside of the bowl. We call it a dam ring that separates the fuel and water.

Figure 01: A Purifier

Usually, marine fuel oil contains a little amount of water. Thus, the water outlet of the purifier has a greater radius than that of the fuel outlet. There is a gravity disc within the water outlet. It can control the radial position of the fuel-water interface. Eventually, the particulate matter will collect on the walls of the bowl. Furthermore, free water continuously discharges out from the purifier.

What is Clarifier?

Clarifier is a type of centrifugal separator that we can use to separate solid impurities from fuel. However, a clarifier can remove some quantity of water as well. To form a simple clarifier, we can add an inlet and an outlet connection, and we can increase the efficiency by increasing the number of discs that we include in the clarifier; it increases the surface area, thus, helps in better separation.

Figure 02: A Simple Clarifier

During the process, the untreated oil is carried by the centrifugal forces towards the periphery of the bowl followed by passing through the set of discs. Consequently, the actual separation of fuel and dissolved impurities takes place. On each solid particle, two forces will act namely, centrifugal force and residual force. The centrifugal force acts on particles to push the particle upwards to direct it to the periphery. On the other hand, the residual force act on the denser particle and helps to drive the particles towards the periphery. However, the light particles are directed towards the centre of the bowl by the residual force and raised to the outlet connection. Here, denser particles are solid impurities whereas light particles are liquid particles (fuel oil).

What is the Difference Between Purifier and Clarifier?

A purifier is a type of centrifugal separator that we can use to separate two liquids with different densities while a clarifier is a type of centrifugal separator that we can use to separate solid impurities from fuel. The key difference between purifier and clarifier is that the purifier consists of a dam ring to create a line of separation between fuel and water whereas the  clarifier consists of a sealing ring to prevent the fuel tank from water and dissolved impurities. In brief, a purifier separates the fuel from water along with some solid particles while the clarifier separates the fuel from solid impurities along with some water. Hence, this is also an important difference between purifier and clarifier.

The below infographic of difference between purifier and clarifier provides further description on the differences between both.

Summary – Purifier vs Clarifier

Purifier and clarifier are two types of centrifugal separators that we can use to obtain a pure form of fuel oil, especially in ships. The key difference between purifier and clarifier is that the purifier consists of a dam ring to create a line of separation between fuel and water whereas the clarifier consists of a sealing ring to prevent the fuel tank from water and dissolved impurities.

Reference:

1. “Separator and Clarifier – What Is the Difference?” Brighthub Engineering, 12 Jan. 2010. Available here  
2. “Centrifugal Separators .” How An Engine Starts On Air. Available here 

Image Courtesy:

1.”Purifier”By Marcusroos – Own work, (CC BY-SA 3.0) via Commons Wikimedia  
2.”Mass bal clarifier” (CC BY 2.5) via Commons Wikimedia 

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