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Boiler Operator's Handbook
Published in Carl Bozzuto, Boiler Operator's Handbook, 2021
The typical water cooler in an office has an evaporator that is a coil of two tubes, one inside the other, with the refrigerant inside the inner tube and the water for drinking in the annular space between the two tubes. Heat transfer rates from metal to flowing water are higher than for a gas like air. Fins are not economically justified on something so small that only requires a little extra length of tubing to make up the difference between heat transfer to boiling liquid and heat transfer to flowing liquid.
Experimental investigation of the sloshing influence on FLNG liquefaction system
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2023
Xueyu Chang, Yuxing Li, Jianlu Zhu, Xuehui Zhang, Wen. Li, Chao. Wang, Haisheng Chen, Jie Chen, Weiping Zeng
Figure 1 is the flow chart of DMR. This process is mainly applied to the liquefaction of natural gas at sea, which need to be adapted to the changes of the marine environment. The pre-cooled refrigerant is compressed to 4 MPa through two stages compression and then cooled to 25°C, forming gas-liquid two phase. Then the two phase refrigerant is divided into two strands of flow, gas refrigerant and the liquid refrigerant, which are cooled to −21°C and −50°C in the exchanger respectively. The pressure and temperature are dropped after throttle valve1 and throttle valve2. Then the pre-cool refrigerant would cool the natural gas, cryogenic refrigerant and high temperature pre-cool refrigerant. Finally, the pre-cooled refrigerant gathers in the plat fin heat exchanger and then returns to the compressor2. The cryogenic refrigerant is cooled to −50°C after precooling, forming gas-liquid two phase. Then refrigerants were cooled to −153°C and −110°C in wound tube heat exchanger respectively. The pressure and temperature are dropped after throttle valve3 and throttle valve4 to cool the natural gas and high temperature refrigerant. Finally, the cryogenic refrigerant gathers in the wound tube heat exchanger and then returns to the compressor1. The system uses water cooler to cool the working fluid. The nature gas, 4 MPa, 25°C, is cooled and super cooled in plat-fin heat exchanger and tube heat exchanger. The pressure of natural gas is dropped after throttle valve5 and the natural gas turn to LNG. Then the LNG becomes gaseous again through air-heated vaporizer. Finally, the nature gas returns to the compressor3.
Treatment of wet electrostatic precipitators wastewater by supercritical water oxidation
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2022
Aytuğ Tekbaş, Nihal Bektaş, Mesut Tekbaş, Ercan Gürbulak, Ebubekir Yüksel
The reactor is made of SS 310 stainless steel to withstand a maximum temperature of 650°C and a pressure of 400 bar. The process flow is adjusted using the frequency control system and all temperature controls of the process are done by proportional integral derivative (PID). Three are placed in the upper, lower, and middle parts of the supercritical reactor, two are located in the inlet and outlet lines of the preheat exchanger and one is in the outlet line of the cooling exchanger. Reactor temperatures were measured at six different points with K-type thermocouples (temperature-controlled accuracy ± 0.5%). The system is conditioned with tap water before each experimental study. After the conditioning process is completed, the chipboard wastewater was first mixed in the feed tank to ensure a homogeneous mixture. Then, hydrogen peroxide (H2O2) and wastewater are fed into the reactor from two separate lines with the help of high-pressure pumps. In this feeding type, H2O2 was expected to completely convert to O2. The gas stream from the SCWO reactor is first sent to the preheating and water cooler units and then sent to the liquid–gas separator for liquid and gas separation. The analysis of TOC and TN were carried out in the collected liquid samples.
Slow pyrolysis of indigenous Makarwal coal: characterization, kinetic study, and calculation of design parameters
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2022
Hafiz Miqdad Masood, Najaf Ali, Tanveer Iqbal, Muhammad Zafar
Initially purge gas start to reduce oxygen with the flow of 0.2 l/min till the end of experiment and placing the 20 g of coal sample having particle size from 0.21 to 0.50 mm in fixed bed reactor in Figure 1. Switch on the electric heater after half an hour and keeping the constant voltage supply. First experiment was run at 95 V and the final temperature was set to 500 ºC. Chilled water was supplied inside the tube of the condenser and pyrolytic gases pass through outside the condenser. Chilled water was supplied through the water cooler continuously till the end of the gases evolved from the reactor. When the required temperature was achieved, then switch off the electric heater,sweep gas flow rate after that collected the desired sample and noted the weight of yield. Charcoal is the main product in pyrolysis of local coal in this research. Similarly, the other experiment was done by varying the particle range and supplied of electric heater varying by the opening of knob.