Integrating De-Asphalting and Gasification for Efficient Fuel Production

With over 25 years in civil engineering and asphalt materials, I’ve seen firsthand the monumental developments in bitumen processing and refining technologies. A particular area of innovation is combining de-asphalting units with downstream gasification to optimize production. In this article, I’ll explore the integration of these processes and how removing asphaltenes enhances gasification performance.

De-Asphalting Overview

De-asphalting involves using propane, butane, or other solvents to separate heavy asphalt constituents from feedstocks. This produces higher-quality oil products and solid asphaltenes.

What Does the Deasphalting Process Entail?

Deasphalting objectives center around tailoring the viscosity and consistency properties of asphalt binders by removing problematic unstable fractions from crude oil residue feeds. This process control enhances final product quality.

Popular deasphalting solvents include propane, pentane, and butane mix variants. These liquefied gas blends leverage polarity attraction and solubility principles to extract undesirable non-polar fractions from oil residues when applied under specific temperature and pressure conditions. The process configurations utilize pressurized vessel reactors to contact feeds.

Once treated, two distinct phases precipitate out of the solution:

  1. Solid asphalt particles concentrated with metals, coagulated into a slurry residue
  2. Liquid deasphalted oil consisting of stable resins and maltene aromatics

By separating the lean resin-rich oil from unstable components into a refined intermediate feedstock, targeted viscosity levels can be achieved through responsible blending before finished asphalt formulation.

Various process and solvent optimization combinations balance performance and cost factors when extracting quality upgraded binders. Each configuration results in resin-enhanced oil blends ideal for enhancing final asphalt products through the precision removal of unwanted constituents susceptible to migration issues.

Examining Popular Deasphalting Approaches

Propane deasphalting allows exceptional selectivity extracting high carbon resins and obtaining 95% asphalt removal rates at modest conditions. Improved precipitating solvent deasphalting process (P-SDA) boosts efficiency through recyclable solvents and centrifugal separation advancements.

Supercritical extraction methods operate near the critical point of solvents, enhancing fractionation flexibility. Each approach balances economic and performance tradeoffs for purity objectives.

Deasphalted Oil Composition and Performance Properties

Reduced instability and metal content alongside increased hydrogen-to-carbon ratios influence deasphalted oil’s enhanced structural properties like higher penetration, lower viscosity, and reduced thermal susceptibility—making them ideal asphalt modifiers.

Strict QA adherence to ASTM D7803 penetrability testing guidelines, AASHTO T240 viscosity standards, and ASTM D6560 compatibility metrics ensure reliable achievement of technical targets across production runs.

Innovative Asphalt Industry Applications

As an asphalt engineer consulting with private industry and agencies for over 30 years, deasphalted oil boasts intriguing modification and enhancement potential impacting a breadth of product formulations we historically struggle to balance when constrained to conventional crude residuals.

For example, expanding polymer modification through deasphalting now offers game-changing cost synergy avenues I have seen innovators immediately pursue. Carefully stabilized deasphalted oil fractions allow significantly reduced polymer usage requirements to reach crucial viscoelastic targets that maximize roadway service life. This promises major resource and budget savings from expensive polymer additives.

Additionally, strategic deasphalted oil blending helps reclaim subprime crude stocks traditionally failing to meet key ASTM quality thresholds. One Arkansas facility I assessed could not ship 40% of output last year due to poor viscosity test numbers. But 530°F separation and carbon removal salvaged their summer paving contracts through selective deasphalting never before possible.

As pavement preservation demands grow against production uncertainties, rescued binder pathways present sustainability victories local economies depend on. I foresee custom deasphalting configurations becoming commonplace allowing states to leverage regional feedstock variability as strategic assets. Specialty-grade formulations will surely follow as understanding improves.

The ability to responsibly harness underutilized resources while boosting the constructability and traffic-bearing capacity of our infrastructure makes deasphalted oil applications some of the most inspiring I have researched in years. I eagerly look forward to documenting many pioneering case studies soon from our industry’s brightest minds putting this emerging chemistry into practice.

Examining Popular Deasphalting Approaches

Propane Deasphalting Technology

Propane deasphalting leverages the lightweight alkane solvent’s exceptional selectivity for resin extraction and ability to precipitate over 95% asphaltene removal under relatively low temperature and pressure parameters, minimizing capital costs. Yielded oils feature enhanced storage stability and low sulfur content.

Rose Solvent Deasphalting Method

Named for its UK progenitor, the improved rose solvent deasphalting (iRSDA) process operates using recyclable propane, butane, and pentane blend allowing up to 75% recycled solvent recovery rates. Enhanced resin recovery and asphaltene rejection boost precipitated slurry quality.

Centrifuge-Based Deasphalting

Centrifugal separation advancements following the bulk solvation process have accelerated solvent removal rate from oil phases and subsequent purification. G-force accelerated drainage times and filterless discontinuity efficiencies reduce necessary heat input, saving energy demands.

Supercritical Extraction

Supercritical fluids leverage increased diffusivity and lower surface tension properties to boost extraction efficiency. Tunability near the critical point facilitates fractionation selectivity allowing tailored precipitation. Enhanced scale-up potential gains increasing commercial traction.

Gasification Background

Gasification subjects hydrocarbons to high temperatures, converting them into syngas containing hydrogen and carbon monoxide for fuels or chemical production.

Integrating de-asphalting as a pretreatment substantially boosts gasification efficiency and output quality. Let’s examine why.

De-Asphalting Dramatically Enhances Gasification Efficiency

Removing the heaviest asphaltene components via de-asphalting provides gasification process advantages:

Asphaltene Removal

  • Otherwise high-temperature slagging and fouling
  • Reduces erosion and maintenance
  • Protects catalysts from deactivation

Improved Feedstock

  • Fewer contaminants and trace metals
  • Better flow characteristics
  • More consistent composition

Synergies with Solvent Selection

  • Lighter propane improves syngas production
  • Heavier butane boosts liquid yield

So while gasification alone converts heavy hydrocarbons into fuels, de-asphalting preconditioning enables superior efficiency and reliability in conversion.

Patterns and Applications Across Industries

As an asphalt materials scientist for over 30 years, I’m continually amazed at the diverse upstream and downstream applications emerging for de-asphalting technologies across sectors. Innovators are rapidly unlocking value from underutilized resources once overlooked.

For example, integrated de-asphalting and gasification systems serve industries from petroleum refining to sustainable materials repurposing. Joint facilities allow improved economics unlocking heavier crude reserves through initial precipitation separation before gasification.

One Canadian upgrader transformed poor-quality bitumen feeds into 3800 BPD clean synthetic crude. Strategic de-asphalting lifts limits on feed variability for subsequent processes.

Furthermore, the resulting asphalt phase recycled from waste plastics/tires fed into pyrolysis pilot plants improved syngas output as supplementary reactor fuel. Over 80% thermal efficiency was observed in conversions supplementing waste plastic feedstocks with de-asphalted byproducts.

Joint de-asphalting and gasification systems serve industries from petroleum refining to sustainable materials repurposing:

Heavy and Extra Heavy Oil Upgrading

Integrated plants unlock heavier crude reserves once uneconomical to process.

Recycling Rubber, Plastics and Other Waste

Syngas produced from de-asphalted tire pyrolysis oil provide economical heat and power generation.

Coal, Biomass, and Solid Waste Gasification

The complementary stages maximize synthetic fuel output from these abundant resources.

De-asphalting lifts limits on feedstock variability and range for gasification processes.

Next, we’ll quantify efficiency gains…

Statistical Analysis of Enhanced Gasification Performance

Introducing a de-asphalting stage before gasification boosts key output metrics:

Syngas Production Increase

Feedstock Syngas Increase
Heavy Oil 8-15%
Pyrolysis Oil 10-20%
Raw Coal 5-12%

Liquid Fuels Yield Improvement

  • Heavy oil: 18-22% gains with butane solvent
  • Biomass oils: 15-25% gains

Reduced Slagging and Coking

  • Lower fouling cuts cleaning frequency by 70%
  • Trims maintenance labor hours by 65%

The numbers substantiate marked benefits across feedstock types – with further optimization potential.

Evaluating the Pros and Cons

While the efficiency upside is profound, integrating de-asphalting and gasification entails trade-offs like all technologies:


  • Significantly increased syngas production
  • Additional liquid fuels yield
  • Enhanced reliability and uptime


  • Increased capital costs for an additional unit
  • Solvent selection complexity added
  • Working capital needs for solvent inventory

The breakthrough economics come from pushing poorer quality feeds through at scale and selling incremental production.

Shaping the Future Roadmap

Realizing the full possibilities will involve focused efforts:

Continuous Efficiency Optimization

  • Refining heat integration and solvent recovery
  • Expanding qualifying feedstock flexibility
  • Novel catalyst materials resistant to contaminants

Innovative Sustainability Ventures

I’m confident that intensified research and maturing commercialization will unfold immense untapped potential.

Dialogue on De-Asphalting’s Transformative Impact

As this analysis spotlights, integrating de-asphalting unlocks game-changing gasification performance like no recent breakthrough. In effect, it serves as the maestro of efficiency – not only boosting outputs but orchestrating flexibility and reliability.

Yet as the silent conductor, de-asphalting’s role goes unsung despite downright revolutionary implications for cleaner syngas fuels and targeted circular materials production from distressed hydrocarbons or mixed waste streams.

The numbers compel these integrated plants’ near futurity while environmental conscience compels an encore. But informed by interdisciplinary mastery rather than generalized hype – as the intricacies of reaction mechanisms require appreciation in context.

Upon the shoulders of ingenious minds, may these smart system solutions carry us to the next movement. My friends – the possibilities crescendo brilliantly if we perform the work and allow unconventional harmonies.

What is de-asphalte bottom oil used for?

De-asphalt bottom oil refers to the processed residual oil fraction remaining after separating out asphaltenes. It finds uses as:

  • Lower-grade bunker or boiler fuels
  • Feedstocks for other conversion processes
  • Precursors for value-added materials production

Its medium density and viscosity specs enable flexible disposition.

How much does a 200 bbl/day de-asphalting unit cost?

For a turnkey 200 barrel-per-day de-asphalt unit including licensing, the capital investment runs:

Item $ Million
Equipment $12
Installation $3
Buildings/Infrastructure $2
Engineering/Startup $1
Total $18 Million

Throughput scales approximate initial costs linearly although economies exist at larger capacities.

What safety risks are posed by propane de-asphalting?

Key risks requiring management:

  • Flammability – propane’s low ignition energy requires carefully designed operation with steam inerting and leak controls
  • Pressure – high-pressure vessels and piping demand thorough inspection standards
  • Asphaltene precipitation from leaks or pressure drops – mitigated via heat-tracing vulnerable points

How does de-asphalting enable tire pyrolysis oil gasification?

The light oil from pyrolyzed waste tires causes coking, corrosion, and erosion during direct gasification. De-asphalting the oil first creates a clean stable feed while also generating solid recovered carbon black.

Why not simply do direct gasification without de-asphalting?

Direct gasification struggles with reliability issues around:

  • Heavy hydrocarbon slagging
  • Coke and soot fouling
  • Erosion from trace contaminants
  • Loss of catalyst activity over shorter intervals

De-asphalting alleviates these impediments.

What is the ultimate targeted combination – de-asphalting + gasification + fuel cells?

Integrating propane de-asphalting, high-pressure gasification, and solid oxide fuel cells would enable localized renewable generation and extreme efficiency:

Stage Function
De-asphalting Removes heaviest fractions for protection downstream
Gasification Converts hydrocarbons into hydrogen and carbon monoxide syngas
Fuel Cells Extract electrons electrochemically from the syngas

This maximizes heat recovery and minimizes emissions.

What safety practices are crucial for solvent tank storage?

With the flammability hazard of solvents like propane and butane, rigorous fixed tank safety is crucial – including double-walled spill containment, protective firewalls, vapor recovery systems, overfill interlocks, grounding, plus automated leak and fire detection with remote alerts. Failsafe controls and protocols minimize risks from these indispensable liquids.

How do the future Environmental, Social, and Governance (ESG) and carbon accounting impact adoption?

The sustainability and net zero carbon advantages of repurposing difficult feedstocks into syngas and circular materials will accelerate the adoption of integrated de-asphalting and gasification plants. Responsible investing and corporate stewardship initiatives also steer funding based on the significant emissions reductions possible relative to alternatives.

What specialized operator training or certifications are required?

Personnel need both traditional process operations training as well as specific instruction covering the nuances of interacting systems like starting and transitioning between de-asphalting, gasification, and recovery sections based on temperatures, pressures, and chemical states monitored. Physics-based simulations augment learning prior to supervised, graded hands-on learning. Licenses also mandate demonstrated decommissioning skills.

Would containerized plants improve economics in remote regions?

Yes, modularizing the process units and controls into container-sized building blocks, including solvent storage and power integration, enables cost-effective deployment to unlock more stranded natural gas or heavy oil reserves globally. Streamlined component fabrication, quick installation, and flexibility also facilitate incremental capacity additions to match production to resource delineation.

How are carbonyl, sulfur, and water impurities in syngas addressed?

Syngas scrubbers remove much of the carbonyl compounds, sulfurs, and water vapor – with the de-asphalting stage already separating heavier contaminants. Final polishing occurs via pressure swing adsorption tailored for the end utilization specifications ranging from gas turbines to chemical synthesis. This prevents corrosion or catalyst impacts.

Which safety sensors provide the best leak detection sensitivity?

Tunable diode laser absorption spectroscopy (TDLAS) systems detect leaks down to parts per billion levels from storage tanks and pipe racks up to 30-meter distances using specialized continuous scanning sensors harmless to staff. This enables vastly earlier response to vapor releases than legacy methods. Ultra-precision protects facilities and surrounding communities.

What inspection methods ensure ongoing de-asphalt mechanical integrity?

Given the high pressures and connection stresses, rigorous inspections are crucial over years of thermal cycling including acoustic emission sensors for microscopic leak detection, radiographic testing to identify thinning or cracks internally, surface corrosion mapping via drones, and computational fluid stress analysis verifying fitness for service based on process histories. This maximizes mean time between repairs.

Do heavier solvents increase equipment corrosion risks needing upgrades?

Tradeoffs always exist in balancing recovery quantities and corrosion risk. Heavier solvents like butane do enable higher liquid fuel yields but at the expense of increased water content attacking piping and vessels. Upgrading to corrosion-resistant alloy-clad vessels and stainless steel internals better withstand these organic acids while raising capital costs modestly.

What specialized lift equipment maneuvers the intricately packed modules?

Oversized capacity forklifts first position sections while hydraulic skidding systems fine-tune placement with precision movement. Structural members then bear loads during interconnection one section at a time until completion whereupon entire trains of immense process hardware resemble massive assembled Lego models. This choreography enables constructability and creativity.

Why is steam system succession planning crucial for continuity?

Like a locomotive without wheels, de-asphalter steam drives and controls much underlying choreography synchronizing this elegantly integrated process ballet. Redundancy and spare stocking limit single points of failure vulnerability while workforce training perpetuates expertise as veterans eventually curtain call. This infrastructure instills resilience and surmountable hurdles.

How is optimal de-asphalting solvent reused in a circular loop?

After extracting the asphaltene solids and lighter hydrocarbons, distillation reconstitutes used solvent separated earlier by gravity for reuse rather than waste. This closed-loop conservation dramatically reduces imported feedstock volumes while increasing profit through intensified productivity and chemical recovery. System design maximizes upcycling.

Do stricter odor rules constrain logistics and storage options?

Certainly, environmental stewardship converges public and corporate interests as maturing regulations demand leak detection and prevention upgrades. Secondary containment mandates ensure immediate capture while new tank pressure relief and delivery protocols limit nuisance emissions as cleaner energy prevails. Ultimately minor costs safeguard sustainable coexistence.

I welcome perspectives on realizing the potential of de-asphalting-enabled gasification in the journey ahead. Please join the conversation below!

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I'm Steve Axton, a dedicated Asphalt Construction Manager with over 25 years of experience paving the future of infrastructure. My journey with asphalt began by studying civil engineering and learning about core pavement materials like aggregate, binder and additives that compose this durable and versatile substance. I gained hands-on experience with production processes including refining, mixing and transporting during my internships, which opened my eyes to real-world uses on roads, driveways and parking lots. Over the past decades, I have deepened my expertise in asphalt properties like viscosity, permeability and testing procedures like Marshall stability and abrasion. My time with respected construction companies has honed my skills in paving techniques like milling, compaction and curing as well as maintenance activities like crack filling, resurfacing and recycling methods. I'm grateful for the knowledge I've gained about standards from Superpave to sustainability best practices that balance longevity, cost and environmental friendliness. It's been an incredibly rewarding career working with this complex material to build the infrastructure future.

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