pH-Based Control of the Kinetics and Process Safety of the Highly Exothermic Reaction Between Ammonium Chloride and Sodium Nitrite for Flow-Assurance Applications

SPE Journal ◽  
2021 ◽  
pp. 1-9
Author(s):  
Felipe J. S. Bispo ◽  
Vinicius Kartnaller ◽  
João Cajaiba
Keyword(s):  
Ammonium Chloride ◽  
Heat Generation ◽  
Sodium Nitrite ◽  
Exothermic Reaction ◽  
Ph Control ◽  
Runaway Reaction ◽  
Process Safety ◽  
Heat Generation Rate ◽  
Thermal Risk ◽  
Over Time

Summary The highly exothermic reaction between ammonium chloride (NH4Cl) and sodium nitrite (NaNO2) has an important application in the area of flow assurance. Because of the high heat generation, this reaction has been used as a heat source for the fluidization of low-melting-point deposits formed during oil and gas production. Because this reaction is strongly pH dependent, the incorrect choice of pH can result in an uncontrollable temperature increase caused by the system’s inability to dissipate the large amount of heat generated in a short time, causing accidents such as structural damage and explosions. Thus, the aim of this work was to study a method that involved adjusting the pH over time to ensure controlled heat generation, with high calorimetric conversion, and avoid the development of a thermal-runaway reaction (pH-based control of the kinetics and process safety). The kinetics and thermodynamics of this reaction were studied using heat-flow reaction calorimetry and attenuated total reflection (ATR)-Fourier-transform infrared (FTIR) (ATR-FTIR) spectroscopy. Following a semiempirical approach, calorimetric and spectroscopic data were fitted to a kinetic equation using nitrite, ammonium (NH4+), and hydronium concentrations. The molar enthalpy calculated was –322.92 kJ/mol, and the Arrhenius parameters were determined as the frequency factor [ln(A)] = 22.21 and the apparent activation energy (Ea) = 63.40  kJ/mol. The kinetic model constructed made it possible to properly evaluate the pH profile that should be maintained to control the kinetics (heat-generation rate) and process safety [time to maximum rate under adiabatic conditions (TMRAD)] of the reaction. The strategy of adjusting the pH over time ensured controlled heat generation and high calorimetric conversion, which cannot be achieved by simply adding catalyst at the beginning of the reaction, and minimized the risk of developing a runaway reaction. However, in real applications, the pH control must be made using the balance between the thermal risk (TMRAD) and the performance of the method (qr), because although it is possible to decrease the thermal risk (increase the value of TMRAD) by increasing the pH, this increase is accompanied by a decrease in the heat-generation rate. Thus, from the proper balance of these factors (qr and TMRAD), pH control can ensure adequate levels of heat production within an acceptable thermal risk. Supplementary materials are available in support of this paper and have been published online under Supplementary Data at https://doi.org/10.2118/205389-PA. SPE is not responsible for the content or functionality of supplementary materials supplied by the authors.

A novel heat generation acquisition method of cylindrical battery based on core and surface temperature measurements

2021 ◽  
pp. 1-17
Author(s):  
Xiaoli Yu ◽  
Qichao Wu ◽  
Rui Huang ◽  
Xiaoping Chen
Keyword(s):  
Surface Temperature ◽  
Heat Generation ◽  
Discharge Rate ◽  
Total Heat ◽  
Temperature Measurements ◽  
Generation Rate ◽  
Air Cooling ◽  
Heat Generation Rate ◽  
Environmental Chamber ◽  
Average Heat

Abstract Heat generation measurements of the lithium-ion battery are crucial for the design of the battery thermal management system. Most previous work uses the accelerating rate calorimeter (ARC) to test heat generation of batteries. However, utilizing ARC can only obtain heat generation of the battery operating under the adiabatic condition, deviating from common operation scenarios with heat dissipation. Besides, using ARC is difficult to measure heat generation of the high-rate operating battery because the battery temperature easily exceeds the maximum safety limit. To address these problems, we propose a novel method to obtain heat generation of cylindrical battery based on core and surface temperature measurements and select the 21700 cylindrical battery as the research object. Based on the method, total heat generation at 1C discharge rate under the natural convection air cooling condition in the environmental chamber is about 3.2 kJ, and the average heat generation rate is about 0.9 W. While these two results measured by ARC are about 2.2 kJ and 0.6 W. This gap also reflects that different battery temperature histories have significant impacts on heat generation. In addition, using our approach, total heat generation at 2C discharge rate measured in the environmental chamber is about 5.0 kJ, with the average heat generation rate being about 2.8 W. Heat generation results obtained by our method are approximate to the actual battery operation and have advantages in future applications.

Enhancement of Forced Convection Heat Transfer Using Twisted Heater With Exponential Heat Inputs

2013 ◽  
Author(s):  
Makoto Shibahara ◽  
Qiusheng Liu ◽  
Katsuya Fukuda
Keyword(s):  
Heat Transfer ◽  
Forced Convection ◽  
Heat Generation ◽  
Swirling Flow ◽  
Generation Rate ◽  
Transient Heat Transfer ◽  
Heat Generation Rate ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Plate Heater

Forced convection transient heat transfer coefficients have been measured for nitrogen gas flowing over a twisted heater due to exponentially increasing heat inputs (Q0exp(t/τ)). And then, the effect of heater configuration on transient heat transfer by a twisted heater has been investigated comparing to that of the plate heater. In the experiment, the platinum ribbon with a thickness of 0.1 mm and a width of 4.0 mm was used as a test heater. For heat transfer enhancements in single-phase flow, it was twisted at the central part of the heater with an angle of 90 degrees with respect to the upper part of the heater. The heat generation rate was exponentially increased with a function of Q0exp(t/τ). The gas flow velocity ranged from 1 to 4 m/s for the gas temperatures of 313K. The periods of heat generation rate ranged from 46 ms to 17 s. The surface temperature difference and heat flux increased exponentially as the heat generation rate increased with the exponential function. The heat transfer coefficients for twisted heater have been compared to those of the plate heater. They were 24 % higher than those of the plate one. The geometric effect (twisted effect) of heater in this study showed an enhancement on the heat transfer coefficient. It was considered that the heat transfer coefficients are affected by the change in the flow due to swirling flow on the twisted heater. Finally, the empirical correlations for quasi-steady-state heat transfer and transient one have been obtained based on the experimental data.

A Comparative Analysis of the Tumor Pathology and the Metabolic Heat Generation of Growing Malignant Tumors

2020 ◽  
Author(s):  
Alyssa Owens ◽  
Manasi Godbole ◽  
Donnette Dabydeen ◽  
Lori Medeiros ◽  
Pradyumna Phatak ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Heat Generation ◽  
Infrared Imaging ◽  
Malignant Tumors ◽  
Blood Perfusion ◽  
The United States ◽  
Generation Rate ◽  
Heat Generation Rate ◽  
Clinical Patient ◽  
Tumor Pathology

Abstract Cancer is one of the most debilitating diseases in the world, affecting over 9.6 million people worldwide every year. Breast cancer remains the second largest cause of death in women. Despite major advances in treatment, over 40,920 women died of breast cancer in 2018 in the United States alone. Early detection of abnormal masses can be crucial for diagnosis and dramatically increase survival. Current screening techniques have varying accuracy and perform poorly when used on heterogeneously and extremely dense breast tissue. Infrared imaging has the potential to detect growing tumors within the breast based on thermal signatures on the breast surface by imaging temperature gradients induced by blood perfusion and tumor metabolic activity. Using clinical patient images, previous methods to estimate tumor properties involve an iterative algorithm to estimate the tumor position and diameter. The details from the MRI are used in estimating the volumetric heat generation rate. This is compared with the published values and the reasons for differences are investigated. The tumor pathology is used in estimating the expected growth rate and compared with the predicted values. The correlation between the tumor characteristics and heat generation rate is fundamental information that is needed in accurately predicting the tumor size and location.

Effect of Heater Configurations on Transient Heat Transfer for Various Gases Flowing Over a Twisted Heater

2009 ◽  
Author(s):  
Makoto Shibahara ◽  
Qiusheng Liu ◽  
Katsuya Fukuda
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Heat Generation ◽  
Gas Flow ◽  
Generation Rate ◽  
Transient Heat Transfer ◽  
Heat Generation Rate ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients

Forced convection transient heat transfer coefficients were measured for helium gas and carbon dioxide gas flowing over a twisted heater due to exponentially increasing heat input (Q0exp(t/τ)). The twisted platinum plate with a thickness of 0.1 mm was used as test heater and heated by electric current. The heat generation rate was exponentially increased with a function of Q0exp(t/τ). The gas flow velocities ranged from 1 to 10 m/s, the gas temperatures ranged from 313 to 353 K, and the periods of heat generation rate ranged from 46 ms to 17 s. The surface temperature difference and heat flux increase exponentially as the heat generation rate increases with the exponential function. Transient heat transfer coefficients increase with increasing gas flow velocity. The geometric effect of twisted heater in this study shows an enhancement on the heat transfer coefficient. Empirical correlation for quasi-steady-state heat transfer was obtained based on the experimental data. The data for heat transfer coefficient were compared with those reported in authors’ previous paper.

Non-Intrusive Heat Transfer Coefficient Determination in a Packed Bed of Spheres

2010 ◽  
Author(s):  
David J. Geb ◽  
Ivan Catton
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Heat Generation ◽  
Packed Bed ◽  
Computational Procedure ◽  
Spherical Particles ◽  
Average Heat Transfer Coefficient ◽  
Heat Generation Rate ◽  
Average Heat

Non-intrusive measurements of the internal average heat transfer coefficient [1] in a randomly packed bed of spherical particles are made. It is desired to establish accurate results for this simple geometry so that the method used can then be extended to determine the heat transfer characteristics in any porous medium, such as a compact heat exchanger. Under steady, one-dimensional flow the spherical particles are subjected to a step change in volumetric heat generation rate via induction heating. The fluid temperature response is measured. The average heat transfer coefficient is determined by comparing the results of a numerical simulation based on volume averaging theory with the experimental results. More specifically, the average heat transfer coefficient is adjusted within the computational procedure until the predicted values of the fluid outlet temperature match the experimental values. The only information needed is the basic material properties, the flow rate, and the experimental data. The computational procedure alleviates the need for solid and fluid phase temperature measurements, which are difficult to make and can disturb the solid-fluid interaction. Moreover, a simple analysis allows us to proceed without knowledge of the heat generation rate, which is difficult to determine due to challenges associated with calibrating an inductively-coupled, sample specific, heat generation system. The average heat transfer coefficient was determined, and expressed in terms of the Nusselt number, over a Reynolds number range of 20–600. The results compared favorably to the work of Whitaker [2] and Kays and London [3]. The success of this method, in determining the average heat transfer coefficient in a randomly packed bed of spheres, suggests that it can be used to determine the average heat transfer coefficient in other porous media.

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