Hydrogen Recovery form Refinery Off-gases

 

Background 

Hydrogen is one of the main intermediate products largely utilized in 

 

oil and petrochemical industries.

 

• It is used as a raw material and obtained in some processes as a by-product.

 

• The off-gas streams contain considerable amount of hydrogen, which are

 

mostly incinerated in refinery flares as a waste gas.

 

>Hydrocarbons are converted into hydrogen reformers in order to produce

 

the hydrogen needed for hydrogen consuming processes.

 

>Separation of hydrogen from an existing refinery off-gas stream

 

represents an opportunity to achieve significant cost reductions in refineries

>Cryogenic Technology (CT)

 

Separation principle:

 

Cryogenic technology is based on the difference in the relative

 

component volatility at low temperatures.

 

Disadvantages:

 

Extra compressors to increase the pressure at least 20 bar. CO2 separation

 

is necessary to avoid freezing the CO2 in line at low temperatures.

Flash Calculations

 

Learning Objectives

How to make flash calculation in Hysys.

Flash evaporation is one of the simplest unit operation that

 

separates components into liquid and vapor phased on relative

 

volatility.

Saturated Steam Table

 

Learning Objective 

How to obtain saturated steam properties in HYSYS

Background

 

The temperature window for saturated steam is up

 

to critical point of water that is 373.94 °C. So the

 

saturated steam table will be between 100 °C to 373 °C.

 

HYSYS property packages:

 

ASME Steam (1967)- Outdated NBS Steam (1984)-

 

higher pressure range up to 10000 bar and 2000 K.

Problem statement Calculate

 

the saturated steam properties from 100°C to 373°C. Create a table that shows pressure, molar enthalpy and molar entropy.

Bubble Point and Dew Point Calculation

  Learning Objective 

Bubble point and dew point of pure components. 

 Bubble point and dew point of mixtures

Definitions 

Bubble Point: The bubble point is the point at which the first

 

drop of a liquid mixture begins to vaporize.

 

Dew Point: The dew point is the point at which the first vapor

 

of a gaseous mixture begins to condense.

 

Reactive Distillation in DWSIM

Learning Objective 

• How to setup chemical reaction kinetics in distillation column. 

• How to specify reaction chamber inside distillation column. 

• How to recover unreacted reactant and recycle it. 

• How to use pump and valve unit operations

 

Basic Information 

It integrates chemical reaction and distillation in a single apparatus. (reversible,liquid phase reactions)

 Removing one or more of the products is one of the principles behind.

 

reactive distillation:

>reduced capital investment 

>significant energy savings 

>surpass equilibrium limitations 

>simplify complex processes

 >Increase product selectivity

>improve separation efficiency. 

 

Relief Valve Sizing

Learning Objectives 

How to set up a pressure safety valve in HYSYS 

 

HYSYS,VACUUM DISTILLATION/ PART4

Learning objectives

 How to simulate vacuum distillation column to treat atmospheric unit residue.

Problem Statement

 

Additional steam is injected into the Vacuum Feed Heater to increase

 

velocity & minimize coke formation within the heater

Part 4