Developing Coal Tar/ Petroleum Pitches

1
Developing Coal Tar/Petroleum Pitches

• Melvin D. Kiser -
• Marathon Ashland Petroleum Company
• Robert H. Wombles -
• Koppers Industries, Inc.

2
Discussion Topics

• Introduction
• Coal Tar and Petroleum Supplies
• Coal Tar and Petroleum Pitch Manufacturing
• Coal Tar/Petroleum Pitch Product Development

3
Introduction

• First Coal Chemical Recovery Ovens Installed in
  the US in 1893
• By 1915, By-product Ovens Accounted for 97 of
  Metallurgical Coke Produced in US
• Since Then Coal Tar Pitch Has Been Binder of
  Choice for Aluminum, Commercial Carbon, and
  Graphite Industries

4
Introduction, cont.

• Late 1980s and 1990s Closing of US Coke Ovens
  Accelerated Due to Economic and Environmental
  Pressures
• Coke Oven Closures Resulted in Concern for Supply
  of Coal Tar Pitch and Strategies to Deal with
  Anticipated Shortage Being Sought

5
Introduction, cont.

• Oil Industry As It Is known Today Began with the
  Discovery of Crude Oil in Ontario and Western
  Pennsylvania in 1850s
• Refineries Have Concentrated on Producing
  Transportation and Heating Fuel with Little
  Interest in Heavy Products Such as Pitch

6
Introduction, cont.

• During 1960s Some Refineries Began to Show
  Interest in Producing Petroleum Pitch and Some
  Were Successful in Producing High Aromaticity and
  Specific Gravity Pitches
• Evaluation of These Pitches As Binder Pitches Has
  Given Mixed Results with Most Often Reported
  Shortcoming Being Higher Than Desired Carbon
  Consumption

7
Introduction, cont.

• Future Use of Petroleum Pitches Will Probably Not
  Be Driven By Economics But Raw Material
  Availability and Regulations

8
Introduction, cont.

• Strategies to Deal with Shrinking Coal Tar Supply
• Importing Coal Tar
• Importing Coal Tar Pitch
• Developing Processes to Improve Pitch Yield and
  Upgrade Non-conventional Coal Tars
• Using Petroleum Pitches to Supplement Coal Tar
  Pitch Supply

9
Coal Tar and Petroleum Supplies
10
North American coal tar supplies to fall by 18
by 2005
11
North American Binder Pitch Demand
12
Petroleum Supplies

• Yearly Supply of Coal Tar Is 6 MM Barrels (Less
  Than the Volume of Crude Oil Processed Each Day)
• Yearly Supply of Potential Pitch Feedstocks Is
  326 MM Barrels
• Assuming Only 10 Available and Acceptable
  Results in Petroleum Pitch Yearly Feedstock
  Supply of 32.6 MM Barrels

13
Coal Tar and Petroleum Pitch Manufacturing
14
Coke Flow Diagram
One Metric Ton of Coal Yields
Blast Furnace Coke 600 - 700 kg Coke Breeze
50 - 100 kg
70 Solids
Coke Oven
30 Gas Liquid
Tar 35 - 50 L Ammonium Sulphate 10 - 15
kg Ammonia Liquor 60 - 145 L Light Oil 10 -
15 L
Coke Oven Gas 300 - 360 m3
15
PRODUCTION OF COAL TAR PITCH
Distillate Stream
Steam
Flushing Liquor
Heater
200F
Distillation Tower
Tar Feed Tank
2000F
gas
Coal
Tar
Steam

Decanter Sludge
Pitch
Decanter
Coke Oven
Liquor
16
Coke Oven Thermal Cracking
CH2 CH2 CH2 CH3
1,095C No catalyst
C4
17
Petroleum Pitch Manufacturing

• Many Petroleum Products Referred to as Pitch
  (Causes Confusion Among Non-Refiners)
• Different Pitches Share Only Commonality of Being
  Black Solids at Room Temperature
• Characteristics of Petroleum Pitches Determined
  by Feedstock and Processing to Produce
• Reaction Step Used to Generate or Concentrate the
  High Molecular Weight Molecules

18
Common Petroleum Pitch Producing Processes

• Solvent Deasphalting
• Precipitation of High Molecular Weight and
  Aromaticity Molecules
• Specific Gravity of 1.0 g/cc
• Contains Non-aromatic Molecules and High Metals
  Levels
• Oxidation
• Little Incorporation of Oxygen in Product
• Oxygen Generates Free Radicals Which Cause
  Polymerization
• Products Typically Have Low Coking Values and
  High Viscosities
• Thermal Processing
• Thermal Processing Temperatures of 300C to 480C
• Produces High Specific Gravity and Aromaticity
  Product

19
Crude Oil to Petroleum Pitch
Crude Oil
Desalting Dewatering
Atmospheric Distillation
Other Components
Pitch Feed Preparation
Fluid Catalytic Cracking
Vacuum Distillation
Primary Reaction Processes
Secondary Reaction Processes
Liquid Storage
Solidification
1. Feed preparation can consist of any one or a
combination of blending, distillation,
desulfurization and solids removal. 2. Primary
reaction processes may consist of any one or a
combination of solvent deasphalting, thermal
processing, oxidation or catalytic reactions. 3.
Secondary reaction processes may include
distillation, desulfurization, oxidation or
thermal soaking.
20
Petroleum Refinery Catalytic Cracking
CH2 CH2 CH2 CH3
CH3
540C Cracking catalyst
C3
21
Coal Tar/Petroleum Pitch

• Aluminum Industry Experience with 100 Petroleum
  Pitch Not Acceptable
• Suitable Petroleum Materials Must Be Identified
  (100 Materials Evaluated)
• Commercial Testing Began in 1994
• Small Performance Disadvantages Identified
• Efforts to Improve Performance Successful
• Most Economical Solution with Potential Plentiful
  Supply

22
Properties of Typical Pitches
23
Conclusions

• Supply of Coal Tar in North America Is Declining
  Because of Environmental and Financial Pressures
• One Strategy for Dealing with Declining Coal Tar
  Supply Is Coal Tar/Petroleum Pitch
• Because the Refining Industry Uses Pitch to
  Describe a Number of Products with Varying
  Properties, Care Must Be Taken in Selecting the
  Petroleum Component of a Coal Tar/Petroleum Pitch

24
Conclusions, cont.

• Coal Tar/Petroleum Pitch Is the Preferred Long
  Range Solution to the Tar Shortage Because 1) It
  Is Economical, 2) Its Performance Has Been
  Proven, 3) Potential Feedstock Supply Is
  Plentiful and 4) Product Quality Is Consistent
• Coal Tar/Petroleum Pitches with Significantly
  Reduced PNA Contents Have Been Developed
• Coal Tar/Petroleum Pitch Product Development
  Efforts Will Continue