No abstract

While HZSM-5 catalytic cracking of crop oil toward aromatics have been well documented, this work adds to this body of knowledge with a full acid byproduct analysis that provides improved mass balance closure along with a design of experiment optimization of reaction conditions. Fatty acids are an inevitable byproduct when converting any triglyceride oil, but are most often overlooked; despite the impact fatty acids have on downstream processing. Acid analysis verified that only short chain fatty acids, mainly acetic acid, were present in low quantities when all feed oil was reacted. When relatively high fatty acid amounts were present, these were mainly uncracked C16 and C18 fatty acids. Optimization is a balance of aromatics formation vs. unwanted gas products, coke and residual fatty acids. A design of experiments approach was used to provide insight into where the optimal reaction conditions reside for HZSM-5 facilitated reactions. These conditions can then form the basis for further development into a commercially viable process for the production of renewable aromatics and other byproducts.

Polymers for enhanced oil recovery (EOR) purposes are required to have long term mechanical, thermal, chemical, and biological stability across a wide variety of conditions throughout field deployment. In this work we expand upon initial studies of scleroglucan biopolymer stability and demonstrate that scleroglucan solutions retain a significant proportion of their initial viscosity over a large range of stresses. Thermal stability of the biopolymer, scleroglucan, was tested at temperatures of up to 115°C, wherein the samples retained >95 % of the original viscosity over several months, and at 105 °C sclergolucan maintained >95 % viscosity over the course of 720 days. Scleroglucan was found to be chemically compatible with formaldehyde, glutaraldehyde, tetrakis(hydroxymethyl)-phosphonium sulfate (THPS), and 1,3,4,6-tetrakis(hydroxymethyl)tetrahydroimidazo-[4,5-d]imidazole-2,5(1H,3H)-dione (TMAD) for six months at 37 °C, 85 °C, and 95 °C, indicating these biocides have the potential for use in microbial control during scleroglucan implementation under various conditions. Rheological studies indicate the viscosifying power of scleroglucan is largely unimpacted by common reservoir salts (including divalents and trivalents) even through 20 % (wt/wt) salt addition. Microbial risks to polymer stability were also investigated. The susceptibility of scleroglucan to microbial degradation was assessed under reservoir relevant conditions using a bottle test system in which the polymer was incubated with active microbial cultures under various conditions that simulate reservoirs spanning 3.5 % to 17 % salinity and 30 °C to 90 °C. Our tests of microbial degradation found that anaerobic samples incubated with active microbial consortia under lower salinities and temperature lost viscosity with concomitant microbial growth indicating the presence of scleroglucan degrading organisms in the inoculum. However, anaerobic samples at temperatures above 60 °C and salinities greater than 7 % retained viscosity during the experiment illustrating polymer stability under conditions similar to those of harsh reservoirs. This study further refines the window of operation where scleroglucan maintains functional viscosity and may be employed for EOR use.

Background: The replacement of leaded high octane aviation gasoline with an unleaded renewable alternative would decrease the emissions of lead and fossil-derived carbon into the atmosphere. Replacement has been limited by the requirement of a very high octane number in many existing general aviation aircraft engines. Method: Two separate process pathways were developed that generate an unleaded octane fuel with a motor octane number >96 from triglyceride oils (TGs), such as crop oils and algae oil. A series of experiments coupled with process simulations was used to verify the feasibility of both pathways and to provide preliminary laboratory scale data that could form the basis for further development towards a commercial technology. In the first pathway, TG oil is catalytically cracked to produce a high concentration of simple aromatic hydrocarbons. These aromatic hydrocarbons are then alkylated using propylene to form a mixture, which after purification acquires fuel properties compliant with those in the ASTM specification for 100 octane low lead aviation gasoline (100LL AvGas). In the second process pathway, the aromatic hydrocarbons are isolated after cracking using a sulfolane solvent extraction process to increase alkylation efficiency and fuel quality. Result: The results demonstrate that it is technically feasible to produce a replacement for 100LL AvGas using either pathway, and thus these strategies may be attractive candidates for commercialization.

Reservoirs with harsh environments are now being routinely evaluated for applications of chemical EOR. High temperatures and high salinity water are proving to be hurdles chemical manufacturers must overcome. Scleroglucan is a biopolymer with robust viscosifying power, excellent stability under high temperature, high salinity, and resistance to shear. An injectivity test was conducted in the high temperature (180 °F) Adena oilfield to evaluate the injectivity of scleroglucan polymer. Field injectivity test results are compared to those from the laboratory. Polymer parameters evaluated include polymer viscosity, polymer shear, resistance factor, and residual resistance factor. The unique feature of this injectivity test is the bottom-hole pressure data that allowed for direct field measurement of resistance factor and the evaluation of multiple fall off tests. Pressure transient analysis (PTA) allowed for (1) skin to be measured before and after polymer injection to evaluate sand face plugging, and (2) permeability measurements that were used for direct field measurement of residual resistance factor. Conclusions from the injectivity test in the Adena field are: Scleroglucan was successfully injected into a harsh reservoir environment. PTA data provided a field based direct measurement of resistance factor (RF) and residual resistance factor (RRF).PTA fall off test indicated no sand face plugging, in that a constant skin was observed at the well before and after the polymer injectivity test.RRF was measured at the sand face via FBHP and several feet into the reservoir via PTA. Sandface RRF was 1.3, indicating a 25% reduction in permeability, while PTA based permeability (larger radius of investigation) was reduced by 50%, the equivalent of a RRF of 2.Skin for the two fall off tests, before and after polymer injection, show the polymer did not plug nor exacerbate the pre-existing formation damage. The first field injection of EOR–grade scleroglucan was successful. The use of BHP data and fall off testing allowed for field-based values of resistance factor and residual resistance factor to be measured. Typically, these parameters are laboratory derived values and uncertainty exists when scaling up the process. The use of pressure transient analysis in polymer injectivity tests offers an economical option for field evaluation of polymer based EOR technologies.