Oil Shale Retorting

The ATP-Technology

Overview

The Alberta Taciuk Process (ATP) is a large rotating kiln used to extract oil from feed stock such as oil sand and oil shale. The ATP is a multi compartment unit. Each of these compartments or zones serves a unique purpose such as to preheat and dry incoming feed, to allow for thermal reactions to occur for recovery of hydrocarbons, and the combustion of by product coke. The ATP is a dry thermal processing technology (produces dry tailings) and can be used in a variety of applications. These applications include the extraction and recovery of oil from oil sand, oil shale, and in environmental clean-up and remediation projects.

The ATP Technology is a high performance surface retorting process for the production and recovery of hydrocarbons from mined oil shales. Oil shale is mined, crushed, and then retorted pyrolyzed in the ATP processor which uses the oil shale solids as the process heat carrier. The hydrocarbon vapours produced by the pyrolysis of the oil shale extracted from the ATP processor, condensed, and pumped to product tanks.

The performance features and demonstrated capabilities of the ATP Technology include:

 

Full Resource Utilization

The ATP Processor is designed to process finely sized ore (< 10 mm) with the result that 100% of the ore mined can be processed. This ensures the ore body is fully utilised and prevents any waste of valuable natural resources.

Large Unit Capacity

Individual ATP Processors can be designed to process up to ≈ 750 t/h of oil shale depending upon ore properties. Multiple ATP processing trains are installed in parallel to satisfy overall plant capacity requirements. Common upstream, downstream, and utility facilities support multiple ATP trains.

Concentrated Hydrocarbon Vapour Stream

The ATP Processor produces a concentrated hydrocarbon vapour stream which makes product oil recovery and separation straightforward and minimises the size of the equipment.

High Oil Yield

The ATP Technology provides high liquid product oil yields; typically the butane and heavier (C4&+) product yields are > 90% of Modified Fisher Assay (MFA).

Clean Product Oil

Each ATP System incorporates a hydrocarbon vapour scrubber which provides a proven means to remove residual shale fines from the product oil stream. All fines are handled internal to the process – there is no requirement for any filtration or centrifuging operations with their attendant reliability and sludge disposal issues.

High Heating Value Off Gas

The ATP Technology produces a concentrated, high heating value off gas which is available for use as fuel internal to the process plant facility, for steam production, or for electrical generation.

Complete Ore Utilization

The ATP System uses the residual carbon produced during retorting as the process fuel making effective use of the kerogen by-products. All high value liquid and gaseous hydrocarbons are recovered and are not consumed in the process.

Energy Efficient

The ATP Technology employs heat recovery internal to the Processor. Heat from all combustion products is recovered to preheat and dry the incoming feed ore. Heat recovery in the hydrocarbon, ash cooling, and flue gas handling systems provides further benefits in terms of steam production and/or air preheating.

Ore Feed Flexibility

Each ATP system is designed specifically for the oil shale in each deposit. However the ATP Processor is fully capable of handling feed materials having a range in grades and moisture contents. This provides operators with increased flexibility in their mine planning and operations and allows for full use of the available oil shale resource.

Operational Stability

The ATP processor is a large, refractory lined, rotary mineral processing unit which characteristically provides for stable material handling and thermal processing. Rotary machines are recognised for their tolerance to variations in feed materials and transient operations.

Robust Design

Each ATP Processor is designed and constructed using established heavy rotary machine practises as found in mill and kiln designs. The mechanical design of the processor machine structure, support systems, and drive trains is fundamentally sound, reliable, and robust.

Environmental Performance- Spent Solids

The ATP Technology produces a dry, hydrocarbon free spent ash. With good mining practices, this material is typically suitable for direct backfill in the minesas part of the pit reclamation and restoration sequence.

Environmental Performance- Flue Gases

Each ATP System is equipped with flue gas scrubbing and emissions control systems engineered for the service and as required to meet applicable regulatory requirements.

Operational Safety

The ATP Processor operates at atmospheric pressure and the process reactions depend upon solids mixing generated by processor rotation. During upsets (e.g. power failure), processor rotation ceases which immediately limits hydrocarbon evolution. Proven back-up systems are incorporated in all ATP plants to provide operators with the means to sagely control the plant systems at all times.

 The ATP Processor

 The main component of the ATP System is the ATP Processor, which is a large diameter, horizontal, rotating cylindrical vessel. Inside the vessel are heat transfer and recovery tubes (called the preheat and cooling zones) that provide high thermal efficiency to the machine, a retorting zone where oil is extracted from the shale, and a combustion zone where all of the process heat is generated by burning the carbon by-product after extracting the oil.

The ATP Processor has individual zones in which the process steps occur to separate and recover the various product streams.

The Preheat Zone

• Feed material is heated and dried by transfer of heat from processed, out-going hot spent solids and combustion flue gases flowing through the Cooling Zone.

Lumpy and frozen feed materials are ablated.

Connate water is evaporated and the resulting steam prevents air from entering the Processor with the feed.

• Evolved steam is cooled outside the Processor where condensed water and possibly some trace hydrocarbons are recovered.

• Oversize material and rocks are removed.

The Retort Zone

• Preheated dry feed mixes with hot solids recycled from the Combustion Zone to rapidly achieve reaction temperatures.

• The resulting mix temperature volatilizes or thermally cracks the feed organics in an oxygen deficient atmosphere, yielding hydrocarbon vapour, and coke-coated solid particles.

A concentrated stream of hot hydrocarbon vapours at reaction zone temperature is extracted from the Processor and processed externally.

• Spent solids and coke are discharged to the combustion zone.

Note: The hydrocarbon vapour is cooled outside the Processor; condensed product oil is recovered and may be directly fed to secondary treatment (hydrotreated) or pipelined. Concentrated light hydrocarbon gases are available for further processing and sold as products.

The Combustion Zone

Air is added to burn the coke-coated solids entering from the reaction zone, heating the solids in the combustion zone.

Auxiliary burners supply additional heat if required, such as for start up.

A portion of the hot solids in the Combustion Zone are recycled to the Retort Zone.

The balance of the solids and the combustion flue gases flow to the Cooling Zone.

Note: The combustion of coke usually provides the heat required for the process.

The Cooling Zone

The entering hot solids and flue gases are cooled by indirect heat transfer to the incoming fresh feed in the Preheat Zone.

The hydrocarbon-free solids are discharged and transported for disposal to mined out pit areas or other landfill. Spent shale is moistened for dust control, but no wet tailings ponds are required.

Flue gases are discharged via a treatment system for removal of fine solids, acid gases, and other contaminants as required to meet environmental criteria

 

 

ATP: Oil Shale Application

Oil shale is distributed throughout the world and differ greatly in potential oil content and shale oil characteristics. The oil shale industry uses various techniques to extract oil from within the shale. Commercial processes convert organic matter in the shale, called kerogen, into organic vapour that can be condensed to shale oil or used directly as a gaseous form of energy. The ATP uses external fuel for start up and then may be thermally self sufficient since it is able to combust the remaining carbon on the oil shale particles to supply process heat. The shale oil is recovered as a product and off gas can be used as fuel to supplement heat, if required, or it may be used to produce electricity.

ATP from mine to barrel overview

 An oil shale facility typically consists of a mine, an extraction plant, and an upgrading plant. Refining of the upgraded oil can be done on-site or the upgraded products can be sold to an existing refinery.

 

 

 The ATP: Advantages

 

The advantages of the ATP compared to other technologies are:

Ø  The ATP is able to achieve higher oil yields and process all of the crushed feed ore (other retorts discard the -12mm fine size fraction).

Ø  The ATP combines multiple process steps into a single rotating machine that is thermally efficient and mechanically robust.

Ø  The ATP rotating kiln technology uses solids heat transfer to reduce equipment size and avoid gas to solids heat transfer which is characteristic of vertical retorts. These advantages result in a single ATP having much higher capacity than multiple vertical retort units.

Ø  The ATP uses internally produced fuel to supply process heat and recovers heat from waste streams.

Ø  The ATP produces full boiling point range oil and a high heating value off gas which are both valuable products.

 

The ATP Process Products

 

The ATP produces a full range of boiling point fractions. The system can be configured to recover these products to suit specific project requirements. The ATP plant may be combined with a power plant to utilize excess off gas, hydrocarbon liquids, and waste heat.

 

The ATP Processor Products:

  • Coke:  is a solid residue from the shale oil extraction process of producing synthetic shale oil from oil shale. Can be used as a process fuel and for cement and bricks feedstock.
  • Off Gas: high heating value off gas is available for use as fuel internal to the process plant facility, for steam production or electrical generation.
  • Shale oil: can be further upgraded and refined to produce valuable products.
  • Shale oil Refined Products:
  1.  Distillates:
  • LPG: are flammable mixtures of hydrocarbon gases used as fuel in heating appliances, cooking equipment, and vehicles
  • Gasoline: Gasoline is mainly used as an engine fuel in vehicles Refineries and companies that produce the finished motor gasoline sold in retail gasoline fueling stations may add various liquids so that the gasoline burns cleaner and meets air pollution control standards and requirements. There are three main grades of gasoline sold at retail gasoline refueling stations:
    • Regular
    • Midgrade
    • Premium
    • Naphtha
  • Kerosene: kerosene is a light fuel oil obtained by distilling petroleum, used especially in jet engines and domestic heating boilers; paraffin oil. Commonly used as a fuel. Kerosene is typically pale yellow or colourless and has a not-unpleasant characteristic odour.
  • Diesel: Diesel fuel is refined from oil and is used in the diesel engines found in most freight trucks, trains, buses, boats, and farm and construction vehicles. Some cars and small trucks also have diesel engines.
  • Jet Fuel
  • Fuel Oil

2. Sulfur Chemicals: Sulfur in crude oils is mainly present in the form of organosulfur compounds. Hydrogen sulfide is the only important inorganic Sulfur compound found in crude oil. Its presence, however, is harmful because of its corrosive nature. Organosulfur compounds may generally be classified as acidic and non-acidic. Acidic Sulfur compounds are the thiols (mercaptans). Thiophene, sulfides, and disulfides are examples of non-acidic Sulfur compounds found in crude fractions.