Description

Venturi scrubber

Purpose:

Scrubbers have many applications in cement kilns, chemical and pharmaceutical industries, industrial boilers, gold factories, metallurgical industries, and incinerators. Therefore, this simulation aims to have the simulation settings of a sample scrubber. We can simulate all types of scrubbers in different sizes with these settings.

Introduction (Venturi Scrubber, Industrial Application):

The separation of particles from the gas flow is a significant challenge in the industry. One of the best tools to solve this challenge is a Venturi scrubber that removes gas particles. And compared to other scrubbers (wet scrubber, cyclone scrubber, etc.), it is more efficient.

Venturi scrubbers were designed to remove and collect particles for high efficiencies (over 99%). The high capability of Venturi in cases where the volume of incoming gas and its temperature are high has made them popular in various industries and consequently used to remove various particles in many industries.

This capability is especially desirable to reduce the emission of cement kilns and control the emission of simple oxygen kilns in the steel industry, where the inlet gas has a temperature of more than 350 c. Ventures are also used to control the emission of fly ash from incinerators and cement and sulfur dioxide furnaces in industries and boilers.

High liquid-to-gas ratio, liquid atomization, and open structure make it possible to purify highly polluted gases with high efficiency, minimal maintenance, and unlimited flow reversal capability. The ability of this system to remove toxic gases and particles simultaneously in different conditions makes Venturi one of the most flexible systems used.

Venturi is usually used in the first stage of multi-stage systems to control gas or air flow pollution, which is why this scrubber is used in various industries.

Abstract

In this project, ANSYS Fluent software stimulated an industrial Venturi scrubber. Venturi scrubbers collect particles and gas contaminants up to 0.1 micrometers. The amount of water in the device is very high, but it causes more water to contact particles and contaminants.

As a result, particles are trapped in the scrubber and removed from the fluid.​ After simulating the present Venturi Scrubber, it was observed that this device has the efficiency required for industrial applications.

How the Venturi Scrubber Works

The Venturi scrubber uses the inlet gas energy to atomize the gas flow scrubber.

The Venturi scrubber consists of three parts: the convergent, the throat, and the divergent. The incoming gas stream enters the converging part and the gas flow rate increases as the area decrease. The fluid used is also added to the system at the throat or inlet of the converging part. The system inlet gas passes through the throat at high velocity, where the liquid is added, producing many droplets.

Removal of particles and contaminants from the gas stream is done in the throat. It is by colliding the incoming gas stream with fine liquid droplets. The inlet gas then moves towards the divergent part. It is where the flow will exit at a slow velocity and drown in water.

Advantages of Venturi scrubber

1. low maintenance costs
2. small space requirements
3. cooling of hot gases and handling of corrosive flammable or explosive pollutants

Disadvantages of Venturi scrubber

1. comparably high-pressure loss
2. Requires much power

Simulation

We designed the geometry of the present case study by Spaceclaim software, which has the exact dimensions as the Series 720 Venturi Scrubbers model. The meshing of this current model has been generated by Ansys Meshing software. The mesh grid is structured, and the total cell number is more than 4,600,000.

Venturi scrubber simulations are performed Transient with the energy equation, and the k-ε model is RNG as the turbulence model. In addition, multiphase and discrete phase equations are active. The fluids used in this simulation are water for the discrete phase and air for the continuous phase. Coupling of velocity and pressure equations is also performed using the SIMPLE algorithm.

Venturi scrubber Result:

According to the simulation, it is observed that the pressure in Venturi decreases, which increases the velocity and turbulence, and water and particle disturbances are performed better, so the device is simulated correctly.

Suggestion:

A Venturi 720 series scrubber, size 720-2, has been simulated in this project. But if we want to use Venturi scrubber for other industries (with the different gas flow or particle flow). Due to the simulation settings of this size, the optimal state for the desired industry can be achieved with less time.

Attachment:

Geometry

Geometry

Mesh

Velocity Contour

Velocity Contour

Air Volume Fraction

Particle Tracking

The figures above show the sand particles’ condition at different times. However, the animation of the whole 10 seconds of injecting process is extracted.

According to the reported data, the designed water nozzles and flow parameters could restrain sand particles. Only 0.02% of injected particles could escape, proving incredible efficiency. As a result, it can be implemented on the industrial trunk line it is designed for without hesitation.