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The cooling of hydrocarbon-rich gases in industrial processes often leads to severe fouling, which impedes heat recovery, restricts operative conditions and increases maintenance costs. In the present work, we investigate whether self-cleaning surfaces represent a possible solution to overcome this technological bottleneck. Hydrophilic and hydrophobic treatments of compact heat exchanger plates are experimentally and numerically investigated during cooling of syngas produced from biomass gasification. The experimental evidences related to the operation of heat exchanger plates are assessed first, and a deeper insight into the relevant phenomena is thereafter obtained by performing numerical simulations. Our analysis identifies the hydrophobic treatment as the most promising solution and unveils the induced self-cleaning mechanism: the formation of small-sized and movable condensed droplets that enhance the collection and removal of gas impurities. These findings open up new routes towards the development of cheaper, more efficient and sustainable gas cooling systems.

We investigated the additional (secondary) cooling effect of casted strips on the magnetic properties of Nd–Fe–B sintered magnets. The Nd–Fe–B sintered magnets were fabricated with the casted strips prepared without and with additional cooling. Additional cooling was achieved by blowing Ar gas at various pressures (0.1, 0.3, and 0.6 MPa) on the free-side surface of the strips during the strip-casting process. The higher magnetic properties of Hc, Br, and (BH)max of the final Nd–Fe–B sintered magnets were obtained for 0.1 MPa rather than for 0.0 MPa. The best microstructure of the columnar grains in the casted strips was produced with the aid of a lower pressure of gas on the free-side surface. It was found that the microstructure of the strips affects the distribution of grains grown in the sintered magnets. This report demonstrates that the improved magnetic performance of Nd–Fe–B sintered magnets was achieved via additional gas cooling.

This study investigates the properties of green diesel produced by pyrolysis of waste tyres. Specifically, it examines the effects of catalyst type, gas pressure and gas cooling rate on the flash point, Sulphur content and heat value of the product. The results can serve as a reference for the design of the production process in order to improve the quality, Sulphur content, flash point and heat value of green diesel so that it meets Chinese national standards. As well as determining the optimum pyrolysis conditions, this study also analyses product properties and ways to improve these, as an important reference to serve as the basis for future studies.

The problem of the optimal load distribution between electric drives of fans in a multi-section gas cooling unit is considered based on the minimum energy expenditure for cooling. The optimization problem is solved on the basis of the obtained analytical model for the gas temperature at the outlet of the cooling unit. The model takes into account the mutual infl uence of the operating modes of all fans of the installation. A technique for solving the problem of optimal load sharing between electric drives of fans for a linearized process model is developed using the procedure of integer programming. The optimization technique takes into account the individual characteristics of the devices.

This paper concerns the interaction between water sprays and a smoke layer in a corridor, without any interaction with fire activity. Three water sprays are tested, a high-pressure water mist system and two sprinkler systems under different operating pressures. Our study aims to compare the impact of these three sprays on the smoke layer, based on the analysis of temperature and transmittance profiles. Characterization of the smoke layer before spray activation, based on either temperature or transmittance was found to be similar, providing a smoke free layer at around middle height in the corridor. During spray operation, discrepancies were observed in some cases depending on whether the smoke layer was studied based on the temperature or the transmittance profiles. Spray operation may provide gas cooling, resulting in homogeneous temperature profiles, while vertical variations of droplet size and soot or droplet concentration can still induce a variation in transmittance. The impact of water spray on the smoke layer varies with the spray system. For the water mist system and the highest-pressure sprinkler system, the spray operation induces a complete de-stratification with well-mixed steady-state conditions along the corridor as well as strong smoke cooling and visibility alteration. With the lowest-pressure sprinkler system, only a localized alteration of this stratification is observed under the spray, while the environment remains thermally and optically stratified downstream in the corridor despite spray operation. Relationships described in the literature were used to confirm and explain these observations. Ratios were evaluated to compare the drag effect due to the spray and the buoyancy effect related to the fire. All tests provided ratios of drag number over buoyancy number much greater than one. This confirms the ability of these relationships to predict the occurrence of de-stratification. Qualitatively, the highest ratios were found for the high pressure system and for the water mist system, which actually led to the most important de-stratification effects. In contrast, the weaker ratio found for the lower pressure system was still above one, i.e., coherent with a de-stratification which did not affect the whole corridor however.

Bone fracture occurs due to accident, aging, and disease. For the treatment of bone fractures, it is essential that the bones are kept fixed in the right place. In complex fractures, internal fixation or external methods are used to fix the fracture position. In order to immobilize the fracture position and connect the holder equipment to it, bone drilling is required. During the drilling of the bone, the required forces to chip formation could cause an increase in the temperature. If the resulting temperature increases to 47 °C, it causes thermal necrosis of the bone. Thermal necrosis decreases bone strength in the hole and, subsequently, due to incomplete immobilization of bone, fracture repair is not performed correctly. In this study, attempts have been made to compare local temperature increases in different processes of bone drilling. This comparison has been done between drilling without cooling, drilling with gas cooling, and liquid cooling on bovine femur. Drilling tests with gas coolant using direct injection of CO2 and N2 gases were carried out by internal coolant drill bit. The results showed that with the use of gas coolant, the elevation of temperature has limited to 6 °C and the thermal necrosis is prevented. Maximum temperature rise reached in drilling without cooling was 56 °C, using gas and liquid coolant, a maximum temperature elevation of 43 °C and 42 °C have been obtained, respectively. This resulted in decreased possibility of thermal necrosis of bone in drilling with gas and liquid cooling. However, the results showed that the values obtained with the drilling method with direct gas cooling are independent of the rotational speed of drill.

The Radial X-ray camera (RXC) is a diagnostic for the ITER tokamak. During baking and operation of ITER, the detector environment temperature will be up to 240°C, whereas the detectors must be kept below 70°C. Therefore, cooling of the detectors mounted in the camera is critical and necessary. In order to verify the effect of gas cooling for RXC detectors, a relevant test has been designed. Since the outcome of this test will be the supply of the RXC cooling system, the ITER Instrument and Control strategy was selected. Therefore, a Data Acquisition (DAQ) system was developed based on the Experimental Physics and Industrial Control System (EPICS) framework, which implements functions for real-time data acquisition, temperature control, supervision, and archiving. Moreover, it is easy to configure control information according to user requirements. Also, some linear devices were used in the reconfiguration of EPICS. This technical note presents the entire architecture of the DAQ system and the detai...

Variation of the temperature of gaseous combustion products upon pulsed injection of aqueous aerosols (water, NaCl solution, clay suspension) with droplet sizes within 40–400 μm has been experimentally studied at initial gas temperatures from 520 to 910 K. The motion of aerosol droplets in the counterflow of combustion products was visualized by panoramic optical techniques. It is established that the process of gas cooling depends on the degree of aerosol dispersion, NaCl concentration in solution, clay content in suspension, and the conditions of liquid phase injection.

In the article, the possibility of determining the consumption of electrical energy by gas air cooling devices. Special attention is paid to the processing of experimental results. There are some assumptions in the mathematical model that do not affect the final result. The factors influencing the consumption of electric energy by gas air coolers are given. It is stated that the ambient temperature and gas pressure significantly affect the consumption of electrical energy. Thus, based on experimental data, a model of electrical energy consumption by gas air cooling devices of main compressor stations has been obtained.

The possible application of the film-cooling technique against aero-thermal heating for surfaces of high-speed flying vehicles is discussed. The technique has been widely used in the heat protection of gas turbine blades. It is shown in this paper that, by applying this technique to high-speed flying vehicles, the working principle is fundamentally different. Numerical simulations for two model problems are performed to support the argument. Besides the heat protection, the appreciable drag reduction is found to be another favorable effect. For the second model problem, i.e., the gas cooling for an optical window on a sphere cone, the hydrodynamic instability of the film is studied by the linear stability analysis to observe possible occurrence of laminar-turbulent transition.

This paper reports an investigation into a practical cooling issue on a type of fan-forced finned-tube heat exchangers used in Queensland's coal seam gas (CSG) industry. CSG compression facilities in some production sites suffered underproduction in recent summers because of frequent automatic engine shutdowns. The problem is not expected by the manufacturer's design. However, it is suspected of being related to the control systems on the compression facilities triggering the overheating-protection shutdowns due to possible deficiencies in one or some water/gas cooling loops in the facilities’ air-cooled heat exchangers. Therefore, to understand which heat exchangers and what exact reasons cause the unexpected cooling issue, an investigation has been carried out on the cooler units of the gas compression facilities. A field instrumentation measurement on one operating cooler unit has been done, followed by an analysis using a one-dimensional analytical model and a three-dimensional computational f...

An experimental investigation on the heat transfer characteristics of supercritical CO2 during gas cooling process in a helically coiled tube is conducted. The experimental data are obtained over a mass flux range of 79.6–238.7 kg m−2 s−1, an inlet pressure range of 7.5–9.0 MPa and a mean bulk temperature of 23.0–53.0 °C. The effects of mass flux, bulk temperature and pressure on the heat transfer coefficient for helically coiled tubes are investigated. A comparative analysis of the gravitational buoyancy and the heat transfer coefficient is carried out between helically coiled tubes and straight tubes. A new heat transfer correlation of the supercritical CO2 in the horizontal helically coiled tube is proposed based on the experimental data. The maximum error between the predicted results of the new correlation and the experimental data is 20%.

On the basis of experience at numerous modernized steel plants between 2006 and 2015, proposals have been developed for the reconstruction of the gas cooling and cleaning ducts for (350–400)-t converters, as an alternative to the system employed by Primetals Technologies Austria (previously Siemens Voest Alpine). The basic equipment employed in the reconstruction may be manufactured at Russian plants, and its introduction requires minimal reconfiguration of the metal structures in the existing converter shop.

The benefits of cooling coke-oven gas by means of helical final gas-cooling systems are considered. By data analysis, the effectiveness of helical final gas-cooling systems is assessed, for the example of Nexson Group equipment. A general conclusion is formulated regarding the economic benefits of using helical final gas-cooling systems for coke-oven gas, by the reconstruction of existing equipment or by the construction of new closed systems. The results may be useful to steelmakers in formulating corporate development plans and to regional governments in environmental and investment planning.

Penelitian ini bertujuan untuk mengetahui hasil pengolahan limbah plastik LDPE dan PP dengan cara pirolisis, variasi temperatur reaktor pirolisis 300oC, 350oC, 400oC. Hasil penelitian ini diharapkan memberi jawaban mengenai hasil pirolisis limbah pastik LDPE dan PP. Reaktor pirolisis terbuat dari stenlis berbentuk tabung dengan diameter 40 cm dan tinggi total 60 cm. Pendinginan secara bertingkat, pendinginan gas menggunakan air yang dilewatkan dalam pipa. Aliran air sebagai pendingin dengan gas hasil pirolisis secara berlawanan arah, harapannya agar minyak yang dihasilkan semakin banyak karena gas yang terbuang menjadi berkurang. Energi panas berasal dari kompor berbahan LPG. Hasil pengolahan limbah plastik jenis PP dan LDPE menghasilkan minyak, padatan (arang) maupun gas yang dihasilkan di setiap variasi temperatur. Temperatur 300oC menghasilkan minyak lebih sedikit dibandingkan dengan temperatur 400oC di setiap jenis plastik PP maupun LDPE. Semakin tinggi temperatur reaktor pirolisis, hasil yang didapat minyak semakin banyak dan keruh. Semua minyak hasil pirolisis memilik bau yang menyengat dan bila dibakar akan menghasilkan jelaga.

The large diameter main gasline is a high danger level production facilities. Main gaslines are subjects of increased requirements of safe operation. The feasibility of emergency increases with the course of exploitation time. Keeping a gas transmission system in proper working order with ensuring the safety of the environment is a complex problem. Solving this problem requires to apply a multifaceted approach and conduct a detail analysis technical condition in facilities of pipeline system and operations which are proceeding in the process of gas transportation. In this article, it provided rationalization for the necessity to modernize the gas pipelines gas cooling system, taking cue from operation features, and thermal interaction large diameter main gaslines with soil. The usage of air cooling gas equipment with a variable frequency electric drive of the blower motor as a part of complex solvation temperature (thermic) condition stabilization problem of working pattern large diameter main gasline is considered.

The solution of tasks on energy- and resource saving for various industries relates to the rational planning of their operation modes, the efficiency of which is largely determined by the efficiency of heat transfer processes. The determination of temperature for gas cooling modes on linear and booster compressor stations (BCS) is connected with the optimization of the respective technological sections (TS), optimal operation of which depends on the equipment.

We demonstrate a laser diode end-pumped helium gas-cooled multislab Nd:glass laser amplifier. The design and thermal management of the proposed laser amplifier are discussed. The thermally induced wavefront aberration of the slabs was also measured and compared with simulation results. A small-signal single-pass longitudinal gain of 1.8 was measured with a pump energy of 7.3 J. With an injected seed energy of 0.6 mJ, the output energy from the amplifier reached 0.5 J at 0.2 Hz and 0.43 J at 0.5 Hz in a multipass extraction geometry, thus demonstrating the feasibility of diode-pumped, high-energy lasers with direct gas cooling.