Dissertation
Investigation of the effect of nanomaterials and polymeric additives on combustion and sooting properties of multicomponent fuel droplets
University of Iowa
Doctor of Philosophy (PhD), University of Iowa
Autumn 2019
DOI: 10.17077/etd.005187
Abstract
The oil boom in the North Dakota oilfields has resulted in improved energy security for the US. Recent estimates of oil production rates indicate that completion of the proposed Keystone XL pipeline will only fractionally reduce the need to ship this oil by rail. Current levels of oil shipment have already caused significant strain on rail infrastructure and led to crude oil train derailments, resulting in loss of life and property. With the a priori knowledge that crude oils are multicomponent liquid fuels with thousands of constituent chemical species, this work aims to understand crude oil droplet burning and thereby to lead to methods to improve train fire safety. During a derailment, small fuel droplets are most likely to catch fire, so the present work analyses various droplet combustion properties of crude oil obtained from different sources in the US. Also, the addition of nanomaterials to base liquid fuels for the enhancement of combustion properties has long generated interest, since it is linked to improvement in combustion properties in petroleum-derived fuels.
Selecting petrodiesel as a representative multicomponent fuel and pure biodiesel as a representative single-component fuel, this work investigates the effect of acetylene black (AB) nanoparticles on soy-based biodiesel and petrodiesel. AB nanoparticles were added in various proportions to biodiesel and petrodiesel to make suspensions. Sub-millimeter-sized spherical droplets of such suspensions were ignited using hot wire loops, and the combustion process was recorded using a high-speed camera. Properties such as ignition delay, combustion rate, total combustion time, flame stand-off ratio, and droplet temperature were measured with post-processing of the resulting images. Pennsylvania, Texas, Colorado, and Bakken crudes, as well as polybutadiene-crude blends and nanomaterial-crude colloidal suspensions were analyzed using a similar experimental technique. The soot left behind was analyzed using a Scanning Electron Microscope (SEM).
It was found that polybutadiene (PBD) polymer of different chain lengths affected combustion properties of crude oils in different manner. Notably, PBD with chain length 5,000 (or PBD5k) generally caused a decrease in combustion rate of crude oils tested and PBD with chain length 200,000 (or PBD200k) generally caused an increase in combustion rate of crude oils tested. Multiwalled nanotubes and AB nanoparticles tested with Bakken crude oil revealed that both could increase its droplet combustion rate, and addition of AB could suppress microexplosions. Future work should focus on mixing PBD5k and AB to achieve the best outcomes these additives can deliver: PBD5k can offer decreased combustion rates at certain concentrations and AB can suppress microexplosions at certain concentrations, so there is possibly a tailored mixture of PBD5k and AB that decreases both combustion rates while also suppressing microexplosions. Applications of crude oil combustion enhancement should also be explored, such as improvement in in-situ burning techniques to achieve better crude oil spill cleanup.
Details
- Title: Subtitle
- Investigation of the effect of nanomaterials and polymeric additives on combustion and sooting properties of multicomponent fuel droplets
- Creators
- Gurjap Singh
- Contributors
- Albert Ratner (Advisor)Casey Harwood (Committee Member)James H J Buchholz (Committee Member)Hongtao Ding (Committee Member)
- Resource Type
- Dissertation
- Degree Awarded
- Doctor of Philosophy (PhD), University of Iowa
- Degree in
- Mechanical Engineering
- Date degree season
- Autumn 2019
- DOI
- 10.17077/etd.005187
- Publisher
- University of Iowa
- Number of pages
- xv, 159 pages
- Copyright
- Copyright 2019 Gurjap Singh
- Language
- English
- Description illustrations
- color illustrations
- Description bibliographic
- Includes bibliographical references (pages 143-155).
- Public Abstract (ETD)
The oil boom in the North Dakota oilfields has resulted in improved energy security for the US. Recent estimates of oil production rates indicate that completion of the proposed Keystone XL pipeline will only fractionally reduce the need to ship this oil by rail. Current levels of oil shipment have already caused significant strain on rail infrastructure and led to crude oil train derailments, resulting in loss of life and property. Previous research has investigated various additives for liquid fuels to modify their combustion behavior. Carbon-based nanomaterials are a class of such additives, which are carbon particles, tubes, or platelets with nanoscale (a billionth of a meter) dimensions. Another class of such additives are polymers, which are substances whose molecular structures are long chains of a similar molecular unit bonded together many thousands, hundreds of thousands, millions or more times. This work aims to understand crude oil droplet combustion and thereby to lead to methods to improve train transportation fire safety. Crude oil obtained from different US oilfields has been tested with additives such as nanomaterials and polymers to make it harder to burn while not compromising its value to oil refineries. One of the polymers tested was found to be most effective at decreasing crude oil droplet combustion rate, which is desirable for better transportation fire safety. Carbon-based nanomaterials were found to increase combustion rate, which is unfavorable for transportation fire safety but useful to explore as a method to improve crude oil spill clean-ups with in-situ burning. One of the nanomaterials tested also suppressed microexplosions, which is advantageous for transportation fire safety. Future research should therefore aim at investigating tailored mixtures of polymers and nanomaterials for best results in all categories of improved transportation safety of crude oils.
- Academic Unit
- Mechanical Engineering
- Record Identifier
- 9983779599202771
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