Process Overview

1

• Process Overview
• After a gas well is completed
• the gas is typically drawn from
• the well via a self containing
• portable skid containing a
• driver, compressor and
• separation devices. Care
• needs to be taken to remove
• the liquids and solids from the
• gas stream prior and post
• compression.

• Process Issues
• Liquids and Solids from the
• well can shutdown the
• compression
• Dirty Lube Oil leads to high driver and
  compressor maintenance.
• Coal Fines leads to coating of equipment and
  downstream contamination.
• Salt Deposits lead to plating our of equipment
• Dirty Fuel Leads to inefficient driver
  performance
• Liquid slugging can cause shutdown and damage to
  compressors

2

• Process Issues
• Contaminated inlet gas causes excessive element
  usage and foaming in contactor towers.
• Contaminated inlet gas causes excessive solvent
  use.
• Contaminated inlet gas make the contactor towers
  inefficient
• Solvent contamination can cause plating out or
  plugging of the heat exchangers.
• Poor solvent performance leads to off spec gas

• Process Overview
• Gas from production field is
• collected via inter-connecting
• pipelines to Dehydration plants
• where the water is removed
• and in some cases where H2S
• and CO2 is removed as well.
• Keeping the solid and liquid
• contaminates out of the
• processing plant is the most
• important portion of gas
• gathering.

3

• Process Overview
• Gas Transmission stations are
• designed to increase the
• pipeline pressure and move
• the gas through out the
• pipeline grid. Stations are
• normally every 50 to 100 miles
• along the pipeline and contain
• drivers (turbines) and
• compressors plus the support
• equipment such as separators,
• filter separators and
• coalescers. The support
• equipments purpose is to clean
• the gas coming into and
• departing the transmission
• station.

• Process Issues
• Gas contamination fouls compressors
• Gas Contamination in the fuel gas stream causes
  hot spots in the turbine combustion chamber
  leading to short life.
• Contaminate in the coolant leads to driver
  inefficiency
• Oil Carryover from the compressor clogs
  downstream equipment
• Carryover from Glycol Dehydrator causes
  compressor and downstream problems

4

• Process Overview
• Amine Sweetening utilizes solvent
• to remove H2S and CO2 which are
• both harmful to the pipeline and
• equipment.

• Process Issues
• Contactor Foaming
• Heat Exchanger Fouling
• Heater Tube hot spots
• Extreme corrosion on heating surfaces
• Increased maintenance costs
• Increased solvent usage
• Formation of heat stable salts
• Activated carbon fouling
• Waste disposal increase costs
• pH fluctuation due to acid gas formation
• Cyanide Formation
• Condenser fouling
• Sulfur recover catalyst damage

5

• Process Overview
• Sulften is a Claus tail gas treating
• process designed to treat gas with less
• than 20 CO2.
• As gas enters the system it is heated to
• reaction temperature where it becomes
• hydrolyzed and hydrogenated to covert
• the SO2 producing H2S and water.
• Gas is then cooled and passed into the
• first of two towers to selectively remove
• the H2S.
• The sour water from the stripper tower is
• piped to the sour water stripper and
• selective solvent is stripped. The
• absorber gas is almost pure CO2 while
• the stripper produces almost pure H2S
• which is sent back to the Claus process
• for Sulfur recovery.

• Process Issues
• Corrosion
• Iron Sulfides
• Elemental Sulfur
• Quench Water Solids
• Solvent pH
• Solvent loss downstream
• NOx levels up
• Contactor Foaming
• Solvent contamination in the rich side causes
  most tail gas treating problems.

6

• Process Overview
• Shell Claus Off Gas Treating
• (SCOT) process is a wet
• scrubbing process designed to
• remove sulfur compounds from
• Sulfur Plant tail gas through
• amine absorption. The H2S
• removed is returned to the
• front end of the Claus unit for
• sulfur recovery.
• Protection of the catalyst bed is
• vital, you should assure that
• both liquids and solids are
• removed from the gas stream
• to prevent premature Catalyst
• bed decay.

• Process Issues
• Amine carryover
• Cooler Fouling
• Pipeline corrosion
• Catalyst Bed Fouling
• Tower corrosion
• Compressor life effected

7

• Process Overview
• Large skid mounted engines
• drive compressors, these
• engines generate a great deal
• of heat that needs to be
• dissipated or it will cause
• eventual engine failure. This
• heat is dissipated with the use
• of coolants, normally ethylene
• glycol/water or propylene
• glycol mixture. These coolants
• become contaminated with
• oils, solid particulate and other
• foreign material. These
• contaminates lead to
• performance problems and
• short engine life.

• Process Issues
• Short coolant life
• Pump seal wear
• Thermostat malfunction
• Cylinder wear
• Valve wear

8

• Process Overview
• Over time solid waste in
• landfills decomposes, during
• decomposition gas composed
• of carbon dioxide and methane
• is produced. Landfill gas has
• low heating value (500-550
• BTU) this gas is collected
• under vacuum through a
• system of vertical wells
• sometimes using horizontal
• headers. After this gas is
• cleaned it can be used to
• generate electricity.

• Process Issues
• Corrosion
• Condensation and forming nasty liquid
  hydrocarbons
• Compressor wear due to liquids and corrosion

9

• Process Overview
• Pipeline gas is seldom treated
• after the last compressor
• station therefore gas entering
• plants can contain a variety of
• solid and liquid contaminates
• such as pipeline additives i.e.
• corrosion inhibitors, odorizers,
• hydrate inhibitors, and
• antiscalants.
• It is vital to remove these
• contaminates prior to
• introducing gas to the process
• heaters.

• Process Issues
• Heater Nozzles fouling
• Compressor wear and maintenance
• Heater inefficiency

10

• Process Overview
• Generation of power by Natural
• Gas driven turbines continues
• to grow worldwide.
• Most straight turbine
• generators are known as
• peakers or are used to power
• a specific plant that has no
• practical use for steam.

• Process Issues
• Cleanliness of the fuel gas
• Coolant filtration
• Lube oil Filtration
• Air Filtration

11

• Process Overview
• Combined Cycle Electrical
• Power generation is utilized to
• capture as much output energy
• as possible from the energy
• consumed.
• Electricity is generated and
• goes to the power grid while
• the exhaust gas is directed to a
• boiler which produces steam.
• The steam is then used to
• drive a steam turbine to
• generate additional electricity
• which is fed to the power grid
• as well.

• Process Issues
• Fuel Gas Contamination
• Air Contamination
• Compressor lube oil contamination
• Turbine lube oil contamination
• Steam system make up water contamination

12

• Process Overview
• Coal Fired Power Plants
• generate more electricity
• worldwide than any other type
• of generation system. In this
• process the coal is pulverized
• to a powder and conveyed into a boiler
• along with preheated air where
• it is burned to generate heat.
• The boiler contains heat
• exchanger tubes filled with water.
• The water in these tubes is
• converted to steam which is
• used to drive steam turbines
• which generate electricity.

• Process Issues
• Calcium and Magnesium scaling from poor quality
  make up water
• Plugging of the high pressure ash wash nozzles
• Turbine reliability due to lube oil contamination
  
• Turbine reliability due to poor quality steam

13

• Process Overview
• Pressure relief, incinerator
• gases and some off gases are
• normally flared at most
• refineries.

• Process Issues
• Flame Arrester Failure
• Burner Tip Fouling
• Pilot Flame Outs
• Burner Flame Outs
• Flash Back Explosions
• Excessive release of contaminates into the
  atmosphere.

14

• Process Overview
• Catalytic Reforming utilizes
• low octane naphtha in the
• presence of Hydrogen to
• produce high octane motor
• fuel blending stock. By-
• products of this process are
• Aromatic intermediates

• Process Issues
• Process liquid carryover
• Reactor bed plugging
• Reactor bed short life
• Catalyst carryover

15

• Process Overview
• Hydrotreater feedstock's
• normally contain sulfur, N2,
• Asphaltines and metals.
• Quality fuel oil and catalytic
• cracker feedstock's are
• produced by removing the
• contaminants through
• hydrogen and solid catalyst
• treatment.

• Process Issues
• Reactor Fouling
• Hydrogen compressor failure/high maintenance
• Recycled hydrogen contamination

16

• Process Overview
• Hydrocracking is the process
• which can be used to reduce
• any petroleum fraction to any
• product of lower molecular
• value. During hydrocracking
• N2, sulfur and O2 are removed
• from the hydrocarbon resulting
• in product mixtures of
• naphthalene's, aromatics and
• paraffin's

• Process Issues
• Catalyst bed fouling
• Heat Exchanger fouling
• Reactor Bed damage/plugging
• Liquid carryover from separators
• Heat exchanger fouling

17
COALESCER
COALESCER

• Process Overview
• Solid desiccants such as alumina,
• aluminum or silica gel and
• molecular sieves are used to
• absorb moisture from natural gas.
• Water in the gas is removed prior
• to the gas being introduced to the
• desiccant bed. Gas is preheated
• and introduced into the bed to
• remove trace moisture, when the
• bed is saturated a switch to the
• other bed occurs and the used bed
• is regenerated.

• Process Issues
• Bed fouling from hydrocarbon introduction
• Bed fouling from solids introduction
• Amine and glycol contamination
• Iron sulfides introduction
• Corrosion inhibitors introduction

18

• Process Overview
• Isomerization process
• produces catalytically
• converted straight chain
• paraffin hydrocarbons into
• isomers in a hydrogen rich
• environment. The more
• complex isomers have a
• higher octane rating and are
• used as blending compounds
• for motor fuels

• Process Issues
• Stabilizer internals fouling
• Scrubber carryover
• Catalyst Bed Plugging
• Mol Sieve Bed Plugging