Hot Oil Research Articles

GPU-accelerated transient thermo-hydraulic simulation of weakly compressible restart flow of a non-Newtonian fluid in a long-buried hot oil pipeline

For the complex transient thermo-hydraulic restart process of a long-buried hot oil pipeline, it takes a long time to solve the restart simulation model, which cannot meet the requirements of rapid restart prediction and assessment. The modern GPU is specialized for compute-intensive and massively parallel computation, and it has great potential to accelerate transient thermo-hydraulic restart simulation. According to the computational characteristics of restart model solutions, four types of GPU parallel strategies, from the mapping of grids to the convergence judgment of the discrete equation solution, are combined to accelerate the whole process of a transient thermo-hydraulic restart simulation. The results indicate that the total computation time of the transient thermo-hydraulic simulation is reduced from 185.4 min to 8.8 min, corresponding to an acceleration rate of 21.1, which exhibits a good acceleration effect for a single GPU and is beneficial to the rapid assessment of restart schemes. Based on the GPU-accelerated numerical results, the complex transient thermo-hydraulic restart process with the changing soil temperature field, the non-Newtonian thixotropic behavior of crude oil and flow pattern evolution, is investigated. The analysis reveals that the dominant influencing factors of the restart process vary with the restart time, and the flow pattern evolution plays an important role in the thermo-hydraulic characteristics of the restart process.

Mismatch problem of the model and topology of oil pumping facilities

The mismatch of the model and the topology of real objects is important in modeling technological processes, which is the purpose of this paper. The problem is considered when modeling hot oil pumping in the "Kasymov–Bolshoy Chagan" oil pipeline. In this problem, the topology of objects consists of the linear part of the pipeline and technological equipment (pumps and heating furnaces) of the stations. The accuracy of the simulation results is determined by the calculations of pressure and temperature in the oil pipeline. The pressure in the pipeline is created by pumps at the stations and is determined by the dependence of the pressure and efficiency of the pump on the oil flow rate. These characteristics change depending on the service life of the pump. The identification of the actual dependences of the pressure and efficiency of the pump on the oil flow rate was carried out by the regression analysis of experimental data. The pressure in the linear part is determined by the hydraulic resistance of the pipeline. The actual dependence of the hydraulic resistance coefficient on the Reynolds number and wall roughness was obtained by regression analysis of experimental data. The temperature in the oil pipeline is created at the stations by heating furnaces. The identification of the actual characteristics of the heating furnace was also found by regression analysis of the experimental data. The temperature distribution in the linear part is determined by the heat transfer of oil with the surrounding environment. An undefined parameter for calculating heat transfer is the soil thermal conductivity, which depends on the type of rock and the degree of soil moisture. The soil thermal conductivity is determined in such a way that at a given oil flow rate, oil temperatures at the beginning of the section and soil at the section, the calculated oil temperature at the end of the section has the smallest discrepancy with the actual one. Thus, the determination of the actual dependencies of the objects makes it possible to increase the accuracy of the results of hot pumping modeling and eliminates the mismatches of the model and the topology of the objects.

Computational analysis of coiled tubing concerns during oil well intervention in the upper Assam basin, India

Coil tubing (CT) is widely regarded as one of the most effective servicing tools for dealing with a variety of oil and gas production issues, and it is also commonly used for oil well workover operations in India's upper Assam basin. The current work considers QT 800 to be the CT material used for actual oil well operations. With reference to actual operations carried out in some of the oil wells in the upper Assam basin, the current research analyses the limitations of CTs (QT 800, QT 900, and QT 1000) based on developing limit curves that can depict the operating limit and infer CT failure probability. This study also includes fatigue analysis to determine the likelihood of damage from hot oil circulation, water injection, and nitrogen shot operations while performing them using the CTs (QT 700, QT 800, QT 900, and QT 1000). The current work adopts the methodology of CT assessment based on a computational model built in MATLAB with respect to different oil well parameters in the upper Assam basin. This study takes an innovative approach by taking downhole temperature into account when determining the CT limit for QT 800, which signifies novelty in the current work. According to the computational analysis used in the study on CT limits, mechanical strain, thermal strain, and the combined strain of the CT material all affect CT elongation. This observation was often found to be a research gap in different research works as this aspect in previous studies was not considered while analysing CT operations. The findings of the present study highlight and draw the conclusion that temperature variations in the well and the CTU’s circulating fluid contribute linearly to CT strain. CT’s working limit diminishes with increasing internal and external pressure and diametrical growth, which eventually causes fatigue damage.

Flow synthesis of intrinsically radiolabeled and renal-clearable ultrasmall [198Au]Au nanoparticles in a PTFE microchannel

Synthesis of ultrasmall, citrate functionalized and intrinsically radiolabeled [198Au]Au nanoparticles ([198Au]Au NPs) below 5 nm diameter in a polytetrafluoroethylene (PTFE) microreactor is reported. The radioactive gold precursor along with trisodiumcitrate were premixed and infused into a PTFE microbore tube kept immersed inside a hot oil bath using a syringe pump. The synthesized [198Au]Au NPs were mostly spherical in shape. Systematic studies were conducted to investigate effect of residence time, reaction temperature and citrate to gold ratio on the average particle size of the nanoparticles. The radioactive nanoparticles demonstrated excellent radiochemical stability under both in vitro and in vivo conditions. Biodistribution studies of the ultrasmall [198Au]Au NPs in healthy Wistar rats showed fast clearance of the formulation (>85%ID at 24 h post-injection) predominantly through renal route, with its elimination half-life comparable to that of clinically used small molecule-based radiopharmaceuticals. Overall, this strategy of synthesis of ultrasmall intrinsically radiolabeled nanoparticles in a microreactor will potentially lay down the foundation for further development of renal clearable inorganic radionanomedicines with minimized toxicity for clinical translation.

A reduced order model for triethylene glycol natural gas dehydration system

In natural gas processing plants, glycol dehydration is commonly used to remove water from the gas streams, to avoid pipeline blockage and equipment breakdown due to hydrates formation. This paper proposed a reduced order model developed based on integrated simulation-optimization approach for the glycol dehydration system, with the aim to minimize its operating cost while satisfying pipeline quality specifications. Steady-state process simulation software was used to identify important operating parameters for the glycol dehydration process; these include reboiler temperature and flow ratio of the regeneration column, and solvent flowrate. The identified parameters are built into a non-linear programming model, which was developed as a reduced order model for ease of implementation in the plant. The studied parameters are reboiler duties, hot oil, condenser, and pump, as well as TEG make-up flow rate and CO2 equivalent (CO2-eq) emissions. The Pareto Front is developed to identify the minimum operating cost at different levels of water dew point specification. The work has resulted in the annual savings of more than 34.6%.

ABSORÇÃO DE LIPÍDIOS TOTAIS EM QUIBES DE PEIXE AMAZÔNICO FRITOS POR DIFERENTES MÉTODOS

In this study, the total lipids in kibbeh prepared from minced Amazonian “charutinho” fish (Hemiodus spp.) submitted to different types of frying were compared. Gutted and ticked specimens of this fish were subjected to milling to produce minced fish, whose portions were separated into unwashed and washed. These portions were mixed with several ingredients, formatted and frozen. The frozen kibbehs were separated into three treatments: raw (control), subjected to frying in hot oil and the other, to the electric fryer without oil. All were analyzed for total lipid content (cold extraction method). The results were statically analyzed and compared. When raw or fried in an air fryer, fish kibbeh is less “fat” than meat kibbeh, being indicated as an alternative for individuals seeking a healthier diet. For the consumption of raw kibbeh, fish are more suitable than meat, as it has fewer total lipids the more washes are used in the washing process. However, the more washings of the minced meat occur and the fewer total lipids in the raw kibbeh, the greater will be the lipid increment after frying in hot oil, indicating that this method is inconvenient for the preparation. Therefore, fish kibbeh remains a healthy food alternative for humans if they are eaten raw or fried in an air fryer.

Interaction and motion of two neighboring Leidenfrost droplets on oil surface

Evaporation of droplets on a hot oil surface is a natural phenomenon. However, most of existing studies focus on the evaporation of a single droplet, and the evaporation of multiple droplets is insufficiently understood. Here, we explore the Leidenfrost evaporation of two identical FC-72 droplets on the surface of a hot oil bath. The oil temperature ranges from 73.6 to 126.6 ℃, and the evaporation of droplets each with an initial diameter of 1.5 mm is recorded by an infrared thermographer and a high-speed camera. The shallow oil depth keeps the oil temperature uniform relatively in the slot compared with that in the deep liquid pool due to the larger ratio of the surface area for copper-oil contact to the slot volume. We find that the neighboring droplets evaporate in three stages: non-coalescing, bouncing, and separating. The radius of neighboring Leidenfrost droplets follows the power law <i>R</i>(<i>t</i>)~(1−<i>t</i>/<i>τ</i>)<sup><i>n</i></sup>, where <i>τ</i> is the characteristic droplet lifetime and <i>n</i> is an exponent factor. Moreover, the diffusion-mediated interaction between the neighboring droplets slows down the evaporation process compared with the action of isolated Leidenfrost droplet and leads to an asymmetric temperature field on the droplet surface, thereby breaking the balance of the forces acting on the droplets. A simple dual-droplet evaporation model is developed which considers four forces acting horizontally on the droplet, namely, the Marangoni force resulting from the non-uniform droplet temperature, the gravity component, the lubrication-propulsion force, and the viscous drag force. Scale analysis shows that the Marangoni force and gravity component dominate dual-droplet evaporation dynamics. In the non-coalescence stage, the gravity component induces the droplets to attract each other, while the vapor film trapped between droplets prevents them from directly contacting. When the droplets turn smaller, the gravity component is insufficient to overcome the Marangoni force. Hence, the droplets separate in the final evaporation stage. Finally, we conclude that the competition between Marangoni force and gravitational force is the origin of the bounce evaporation by comparing the theoretical and experimental transition times at distinct stages. This study contributes to explaining the complex Leidenfrost droplet dynamics and evaporation mechanism.

КОРРЕКЦИЯ ТЯЖЁЛЫХ РУБЦОВЫХ КОНТРАКТУР И ДЕФОРМАЦИЙ НИЖНИХ КОНЕЧНОСТЕЙ

Objective: To improve the outcomes of surgical treatment of severe contractures, deformities, and lower limb (LL) soft tissue defects using optical magnification and precision techniques. Methods: 54 patients with sequelae of traumatic injury underwent surgical repair of severe contractures, deformities, and soft tissue defects of the LL. Contractures were accompanied by extended cicatricial deformities and soft tissue defects of the LL. Traumatic injuries often lead to sequelae in children, as observed in 39 patients. The leading causes of burn injuries were boiling water and hot oil. Results: Various types of Z-plasty were used in 29 (53.7%) cases to correct contracture and toe and foot deformities. Tailored surgeries were performed for severe injuries and extended cicatricial deformities with residual defects covered with skin grafts. Optical magnification with precision technique contributed to adequately mobilizing the fasciocutaneous flaps and the neurovascular bundle (NVB) release. By using ultrasonic dopplerography (USDG), it was possible to determine how the degree circulatory disorders in the affected LL is dependent on the duration between injury and presentation at our center, the severity of the contracture, and the size and depth of the soft tissue damage. Purulent wound infection and superficial partial necrosis of the fasciocutaneous flaps occurred in 3 and 5 patients, respectively Conclusion: In managing concomitant injuries, including assessing their extent, appropriately evaluating the initial severity of the trauma is essential. The evaluation requires using additional diagnostic methods and selecting the optimal reconstruction method. Optical magnification and precision techniques enable the effective mobilizing of fasciocutaneous flaps while preserving their blood supply. This leads to adequate mobilization and decompression of the NVB, effectively preventing NVB iatrogenic damage. Keywords: Lower limb, burn, contracture, deformity, soft tissue defect, local plastic surgery.

Characteristics of Plastic Block Wall Materials (PBWM) Using Waste Engine Oil, Crackle Plastic, Mineral Water Plastic Cups Cover and Label of Plastic Bottle Without and With Rice Husk Ash and Natural Aggregates Filling Materials

The increase of waste in Indonesia has reached 38 million tons per year and about 30% of this waste are plastic. One of the efforts is to overcome this issue is by using thin plastic waste from packaging which is rarely recycled to become plastic blocks wall material (PBWM), where the plastic was melted in hot waste engine oil (WEO). The main purpose of this study was to analyze the characteristics of the PBWM. Variation of material proportion was based on trials. The plastic waste was initially shredded to sizes about 5-10mm. On sample productions, the WEO was heated to 200°C then the shredded plastic gradually added and evenly mixed, and poured into a metal mould. The mixture was cooled down to ideal temperature for compaction of 110°C to 125°C, then left to reach room temperature. It was obtained that the Initial Rate of Suction (IRS) test results range from 0.0982-0.1012 kg/ 2.

HOW THE ESTIMATION OF ENTROPY GENERATION AND EXERGY LOSS OF HYBRID NANOFLUIDS GOVERNS THE THERMAL PERFORMANCE OF HEAT EXCHANGER

The present study reports heat-transfer performance, exergy analysis, entropy generation, and pressure drop of shell and helically coiled heat exchanger (SHCHE) with Al<sub>2</sub>O<sub>3</sub>-CuO/water hybrid nanofluid (HYNF) as a working fluid. Helical coil is made of copper material with 54 turns and pitch ratio is 31.35 mm. Hot oil streams at the shell with 75° C, and the working fluid streams at the helical coil with 30° C. The volume fraction of the nanoparticles is considered as 0.1 vol.%. Reynolds number of the oil is fixed as 900 and the Reynolds number of the working fluid varies from 6000 to 15,000. The numerical code is validated with the earlier experimental work. Highest thermal performance is obtained by using 0.1 vol.% HYNF than nanofluids and base fluid. Role of mass flow rate, and Reynolds number on heat-transfer rate, effectiveness, total entropy generation, exergetic efficiency, exergy loss, and dimensionless exergy loss are investigated. An ~ 20% increase in Nusselt number and ~ 48% increment in exergetic efficiency are noted with the usage of HYNF. Entropy generation of SHCHE is lower by adding nanoparticles. This study enables the readers to understand the irreversibility of heat transfer in shell and helically coiled heat exchanger.

The Magic Bangle

The Magic Bangle Shastri Akella (bio) Kartik makes a decision the day his father strikes him: on workday evenings and weekends he’ll pretend he’s a tourist in his home-town. His real home—where he belongs—is a place, he imagines, where it’s safe for him to love men. That Thursday after work he visits the Golconda Fort. He enlists the services of a tour guide, who takes him from the watchtower on the rampart to the courtroom in the heart of the fort. The tour guide tells Kartik about the fort’s many tricks. Alcoves for soldiers to hide in plain sight. Unseen vantage points from which to pour hot oil on intruders. Kartik likes the clap trick best. When the watchtower soldier clapped, the sound traveled all the way to the courtroom: two claps for an approaching friend, one clap for a foe. A happy future is the sound of two claps, Kartik thinks. On Friday he tells his parents he’s going to the Delhi office on a work trip and leaves home with a suitcase. At work he tells his colleagues he’s going to see the Taj Mahal for the long weekend. The office will be closed on Monday for Holi. He takes an Uber to his hometown’s old district and checks into a hotel. His fourth-floor room has a balcony that overlooks the Charminar. He changes into a red kurta, straps his camera across his shoulder, and goes down to join the street traffic: scooterists, pedestrians, buffaloes, and peddlers of steel vessels, velvet pursers, and plastic roses. The air smells of jasmine and stagnant water. He crosses the Jama Masjid, whose stone courtyard is packed with Friday devotees. Men in kurtas lean towards one another, haloed in dusk’s violet glow, their murmurs a collective buzz. The women’s praying quarters, he guesses, are tucked away, out of sight. He takes a right and enters the Bangle Bazaar. He pauses frequently to click a photograph. In a shop empty of customers, a man sitting behind the counter holds his attention. Camera to one eye, Kartik [End Page 20] zooms in on him: his face in profile, illuminated by phone light, his skin the color of chai. A manicured stubble dots his angular jaw. There’s a slight shift in his posture, as if he knows he’s being watched. Not immediately, but at length, he lifts his head and looks. Kartik hones in on the man’s green eyes, framed by his thick lashes, punctuated by a mole on his temple. Click. Kartik lowers his camera and walks into the shop. He occupies the chair the green-eyed stranger points to. What kind of bangles are you looking for? the man asks Kartik. Glass? Enamel? Metal? He speaks a mixture of Urdu and Hindi, and his voice brings to mind the sound of a stone skimming the surface of water. What do you recommend? Kartik asks, holding one hand up. He points to his wrist. The man rubs his jaw. He knows it’s his most attractive feature. He knows Kartik finds him attractive. Kartik can tell, from the tilt of his neck, from the slow movement of his gaze. Bidar, he replies. Silver, with an antique look. A man shuffles out from behind a curtain that leads to the back of the shop. He has a small white beard and wizened coffee skin. He nods at Kartik, then says, adjusting his skullcap, I’m off to pray, Shahrukh. The man’s departure seems to unknot Shahrukh. His shoulders relax under his brown kurta; his face opens like the door of a cage. My parents met at a Shahrukh Khan film, he volunteers. Ammi was selling tickets, and Abbu was buying. He stands and opens the display rack. His hand darts with practiced ease. He extracts six bangles. They release six sonorous clinks as he places them on the glass counter. Which one? Kartik asks him. You pick. Shahrukh sits down and leans forward. Kartik smells the perfume on his neck. A scent full of smoke and wood. His left cheek is scarred somewhat; the tip of his...

Performance Investigations of the Charging and Discharging Processes in a 3-Tank Thermal Energy Storage System

The paper presents a 3 tank thermal energy storage system. The system consists of cold oil reservoir, heat storage tank, and a residual drainage tank. Cold oil flows by gravity into a heating chamber and after being heated to the required temperature, a mechanical thermostat opens allowing the hot oil to flow into a heat storage tank. The storage tank was discharged through the cooking unit by boiling 0.5 litres of water. The used oil flowed by gravity to the drainage tank. The discharge flow rates of 0.5, 2.1, 2.8 and 6.5 g/s were considered. A charging efficiency of 51.3% and overall discharging efficiency range of 15.3 34.7% were achieved. Charging efficiency increased when the source was embedded in the storage tank. The instantaneous discharge power had a peak value for each flow rate. The adopted cooking unit had a thermal transfer efficiency range of 34.7 57.6%. A method for sizing oil based TES systems was proposed and illustrated based on the obtained discharge results.
 Keywords: 3-tank, sizing, discharging, efficiency, thermal energy

Integrated Processes Turning Pepper Sauce Waste into Valuable By-Products

Safe and efficient disposal of millions of tons of pepper sauce waste (PSW) can be a challenge to pepper sauce manufacturers that are concerned about creating environmental hazards from the processing (e.g., preservative salt and vinegar) and intrinsic (e.g., the pungent capsaicins) ingredients. It will be immensely beneficial to process these waste materials before they go to disposal. This work presents integrated approaches for a complete utilization of waste materials by removing and recovering valuable by-products and/or ingredients while succeeding to minimal to zero hazards. Laboratory- and pilot-scale extraction processes were used to demonstrate the recovery of intrinsic compounds from PSW to pungent pepper oil. Flash chromatography was then applied to isolate the pungent capsaicins out of the pepper oil, thus generating a no-heat pepper oil. By processing the waste materials, a number of valuable by-products with various yield percentages were produced. They included (1) hot red pepper oil (RPO, 8.0% v/w), (2) no-heat pepper residue (NHPR, 25.3% w/w), (3) no-heat red pepper oil (NHRPO, 4.0% v/w), (4) capsaicinoids (0.8% w/w), and (5) capsaicin (0.4% w/w). The optimum processing conditions for products 1, 2, and 3 include extracting the waste materials with 95% ethanol twice, each lasting three hours. The optimal isolation conditions of flash column chromatography to obtain products 4 and 5 include the use of the pre-packed chromatography column 130 g Redisep C18, preparing the sample concentration to 100 mg/mL, eluting with aqueous ethanol, and detecting capsaicins at a wavelength of 228 nm. An integrated approach is offered for the complete utilization of PSW. It not only turns organic food waste into numerous new commodities but also significantly reduces the volume and degree of potential environmental hazard to the disposal sites.

Is frying possible in space?

Dietary nutrition and uptake of earth-like foods are extremely important aspects for the health and performance of astronauts, especially during future planned long-term space missions. Despite the major progress in studying and designing systems for crop cultivation in microgravity conditions in the last years, there hasn’t been equal interest in food preparation processes and cooking. There are several reasons for this but it is chiefly because at present astronauts stay in space for a few months at most, so there is no serious nutritional or psychological need for earth-like food habits. This, however, will change drastically in long-term missions, e.g., to Moon and Mars. French fries are a very popular food commodity across many cultural backgrounds on earth and as such they may be appreciated by long-term space travelers of different origin. The process of frying in hot oil is associated with complex heat and mass transfer along with the growth and detachment of water vapor bubbles. These phenomena are strongly affected by buoyancy and gravitational acceleration making the study of frying at space conditions a challenging task. The present work examines potato frying in hot oil during the short duration low gravity conditions achieved in a Parabolic Flight Campaign organized by the European Space Agency. An innovative device has been constructed, allowing the simultaneous observation of bubbles dynamics above the potato surface and the thermal behavior inside the potato flesh. It is seen that even in the absence of buoyancy i.e., during parabolas, vapor bubbles still detach and depart from the surface of potato permitting hot oil to maintain contact with the potato surface and leading eventually to a fried product. Instantaneous overpressure inside potato pores due to vapor formation upon boiling of potato water is suggested as the mechanism generating the force for bubbles detachment and departure. Moreover, the amount of produced vapor is comparable among the examined values of gravitational acceleration, including the low gravity conditions during parabolas. All in all, the results of the present study provide primary experimental evidence that frying can occur in space.

Thermodynamic and economic analysis of new compressed air energy storage system integrated with water electrolysis and H2-Fueled solid oxide fuel cell

In this paper, a novel compressed air energy storage system is proposed, integrated with a water electrolysis system and an H2-fueled solid oxide fuel cell-gas turbine-steam turbine combined cycle system. In the charging process, the water electrolysis system and the compressed air energy storage system are used to store the electricity; while in the discharging process, the H2-fueled solid oxide fuel cell-gas turbine-steam turbine combined cycle system and the compressed air energy storage system are set to generate electricity, achieving zero carbon emissions in the whole process. The waste heat from the exhaust air and the hot oil of the compressed air energy storage system is recycled by the feedwater of the H2-fueled solid oxide fuel cell-gas turbine-steam turbine combined cycle system, leading to an improvement in the energy efficiency. Based on the simulation using ASPEN Plus and EBSILON Professional, energy, exergy, economic, and sensitivity analyses were applied to evaluate the performance of the proposed system. The results show that the round-trip efficiency, energy storage density, and exergy efficiency of the compressed air energy storage system can reach 68.24%, 4.98 MJ/m3, and 64.28%, respectively, and the overall efficiency of the whole integrated system improves by 1.33%.

Analysis of occupational health and safety at skin cracker factory using Hazard and Operability Study (HAZOP)

The Mubarok Skin Cracker Factory is a home industry that produces skin crackers from cowhide, raw, and cooked crackers. Based on the interviews with factory owners, there have been several work accidents, and the production room has very minimal lighting and air ventilation. Based on these problems, the method used is the Hazard and Operability Study (HAZOP), which aims to identify sources of hazards and potential work accidents in the production process to prevent work accidents. The risk matrix analysis shows as much as 24% of the risk is classified as extreme, 65% is classified as high risk, and 12% is classified as moderate risk. In addition, 17 sources of danger were found, namely knives, slippery floors, smoke, hot water, drying roofs, fire, smoke, hot water, ash flakes, hot tanks, wooden board, chopper, loads carried by workers, ovens, hot oil, hot frying pan, hanging boards, and cramped workplaces. The recommendations given by the researcher are to apply health and safety environment regulations and use PPE (Personal Protective Equipment) for employees while working, replace damaged equipment, and implement health promotion in factories.

Style: A new optimization model for Synthesis of uTility sYstems with steam LEvel placement

Moving industrial production to a more sustainable basis requires a step change in the efficiency of site steam and cogeneration systems, coupled with a switch away from fossil fuels to renewable energy sources. This paper presents the first step in the development of an optimization framework capable of identifying a roadmap to move utility systems to a more sustainable basis. Previous approaches to the design and optimization of steam and cogeneration systems have simplified the problem to the extent that many important practical issues have been neglected, restricting the scope of the options included. The use of grossly simplified models has been prompted by the mathematical difficulties of optimizing such complex energy systems. To overcome limitations in previous work and provide a sound basis for future developments, this paper proposes a new superstructure-based optimization model for the optimization of utility systems, accounting for optimum steam level placement. The latter is important for improving systems efficiency and reducing energy consumption. The optimization problem involves the selection of more realistic operating conditions of the steam mains (superheat conditions and pressure). The model accounts for water preheating, as well as superheating and de-superheating for process steam generation and use. Hot oil circuits are also included as hot utility option to overcome potential steam temperature and/or pressure limitations at high temperatures, and with it provide more flexibility in the framework. The general problem requires making several continuous and discrete decisions, where non-linearities and non-convexities from underlying physics and binary decisions exacerbate the complex nature of the problem, yielding a nonconvex Mixed Integer Non-Linear Programming (MINLP) formulation. However, MINLP formulations can become computationally intractable to solve. Thus, to guarantee tractability and fast conversion, the STYLE model develops a novel successive Mixed Integer Linear Programming formulation. The STYLE methodology is applied to two case studies to illustrate the advantages of the synthesis method and the benefits of optimizing steam levels for the reduction of overall energy consumption at industrial sites. The proposed approach addresses major shortcomings inherent in previous research and provides a foundation for future work to explore the next generation of sustainable utility systems.

Analysis of a Costly Fiberglass-Polyester Air Filter Fire

In September 2020, a fire at a liquefied natural gas (LNG) plant in the Arctic areas of Norway received national attention. In an unengaged air intake, the heat exchanger designed to prevent ice damage during production mode, was supplied hot oil at 260 °C. In sunny weather, calm conditions, and 14 °C ambient temperature, overheating of the unengaged air intake filters (85% glass fiber and 15% polyester) was identified as a possible cause of ignition. Laboratory heating tests showed that the filter materials could, due to the rigid glass fibers carrying the polymers, glow like smoldering materials. Thus, self-heating as observed for cellulose-based materials was a possible ignition mechanism. Small-scale testing (10 cm × 10 cm and 8 cm stacked height) revealed that used filters with collected biomass, i.e., mainly pterygota, tended to self-heat at 20 °C lower temperatures than virgin filters. Used filter cassettes (60 cm by 60 cm and 50 cm bag depth) caused significant self-heating at 150 °C. At 160 °C, the self-heating took several hours before increased smoke production and sudden transition to flaming combustion. Since the engaged heat exchanger on a calm sunny day of ambient temperature 14 °C would result in temperatures in excess of 160 °C in an unengaged air intake, self-heating and transition to flaming combustion was identified as the most likely cause of the fire. Flames from the burning polymer filters resulted in heat exchanger collapse and subsequent hot oil release, significantly increasing the intensity and duration of the fire. Due to firewater damages, the plant was out of operation for more than 1.5 years. Better sharing of lessons learned may help prevent similar incidents in the future.

Quantitative Effects of Different Factors on the Thermal Characteristics of New Submarine Hot Oil Pipeline During the Preheating Process

Quantitative Effects of Different Factors on the Thermal Characteristics of New Submarine Hot Oil Pipeline During the Preheating Process

Study on the Microstructure and Mechanical Properties of 60NiTi Alloy Quenched by Hot Oil

60NiTi alloys have a tremendous potential to be used in aerospace, marine and automotive industries. There is still a need to further improve the deformability due to the high brittleness of the previously prepared 60NiTi. In this work, 200 °C hot silicone oil was selected as the quenching medium for 60NiTi for the first time to overcome its high brittleness. It is found that the unique microstructure of 60NiTi quenched by hot oil has a lamellar structure composed of a channel-like NiTi matrix and lenticular Ni4Ti3 phase containing a nano-lath NiTi phase. The 60NiTi exhibits a high compression fracture strain of 10% and large reversible strain of 7.5%; which originates from the superelastic behavior of the NiTi SMA constituent. Upon loading, the R phase reorientation releases the stress concentration at the initial stage; while the stress-induced martensitic transformation accommodates the large elastic deformation of the Ni4Ti3 phase at the later stage. This synergistic effect of the two promotes the compressive deformability.