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Many Types of Cake Filters

In previous post, there are three general types of filters, which are cake filters, clarifying filters, and crossflow filters. In this post, I want to share specifically about many types of cake filters.

When slurry enters cake filters, some solid particles enter the pores of the medium and are immobilized, but soon others begin to collect on the septum surface. A visible cake of significant thickness builds up on the surface and must be periodically removed. Cake filters are used almost entirely for liquid-solid separations.

Cake filters may operate with above-atmospheric pressure upstream from the filter medium or with vacuum applied downstream. Either type can be continuous or discontinuous, but most pressure filters are discontinuous.

Figure below shows many types of cake filters. Read More

How to Determine Cake Resistance in Filtration Systems

Purpose of this post is to determine cake resistance in filtration systems, as a function of operating pressure of filter. Before we jump into the calculation, let us learn first several basic calculation in filtration system.

As filtration proceeds, a porous cake of solid particles is built up on a porous medium, usually a supported cloth. The flow of liquid is laminar because of the fineness of the pores. Therefore, the following equation represented the phenomena:

Q = \frac{{dV}}{{dt}} = \frac{{A\Delta P}}{{\mu R}}

The resistance is made up of filter cloth Rf and that of cake Rc which may be assumed proportional to the weight of the cake. Read More

Introduction to Filtration

These days, I feel like learning topics related to solid processing. After I learned about agitation process and its scale-up, I want to learn about filtration process.

So, in this post I want to share you general preview of filtration process. Honestly in my career until now, I already handled one project related to filtration equipment, which is my very first project: pre-feasibility study of carboxymethyl cellulose plant. The filtration equipment used in the project was rotary vacuum filter.

I hope by learning and writing what I read here in this blog will refresh my knowledge and hopefully useful in the future projects. Read More

Simple Calculation Methods to Estimate Power Required to Rotate Agitator Impeller

This post is a little different from usual. Honestly, I seldom dealing with agitation process. As you may know from my posts, my projects are mostly in oil and gas field. So, agitation process is very rare in oil and gas processing. However, I think I need to learn something beyond what I already learned until now to improve myself.

In this post, I want to share simple calculation methods to estimate power required to rotate agitator impeller. In the future, maybe I will deal with project involving agitation process. Read More

Sizing Horizontal Three Phase Separator

In this post I want to share how to size horizontal three phase separator. The steps used in this post were from Surface Production Operations by Ken Arnold & Maurice Steward. You can learn the details and equations used from the book. In the end of this post, I share free spreadsheet on how to size horizontal three phase separator.

The calculation used in the spreadsheet in for preliminary calculation only. As for fabrication, you may need to discuss more with related vendors and EPC constructors.

Required Data for Horizontal Three Phase Separator Sizing

To size horizontal three phase separator, we need the following data:

  • Oil rate, water rate, and gas rate
  • Operating pressure and operating temperature
  • Properties (density, viscosity) of oil and gas, respectively
  • Retention time of oil and water, respectively
  • Droplet size of liquid and oil to be removed

Read More

Several Types of Three-Phase Separator

Three-phase separators are pressure vessel that are designed to separate and remove the free water from a mixture of crude oil and water. The term of “three-phase separator” is normally used when there is a large amount of gas to be separated from liquid, therefore the size of the vessel is determined by gas capacity equation.

In addition of three-phase separator, there is term called “free-water knockout”. “Free-water knockout” is generally used when the quantity of gas is relatively small compared to the quantity of oil and water. Therefore, the dimension of vessel is determined by oil-water separation equation. 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

Estimation of Gas Turbine Fuel Rates

In this post I want to share how to estimate gas turbine fuel rates. We use heat rates to estimate gas turbine fuel rates.

Heat rate is a measure of thermal efficiency or the amount of energy (in the form of fuel) which must be input to the gas turbine to produce the output power. Heat rate is usually expressed in terms of Btu/(hp.hr) or Btu/(kW.hr) based on the lower heating value of the fuel. Heat rate and thermal efficiency are related as follows:

Gas turbine heat rates vary considerably. They are function of gas turbine rating and type of turbines, which are simple cycle, jet turbine simple cycle, or regenerative. Read More