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Evaporation
Published in Louis Theodore, R. Ryan Dupont, Water Resource Management Issues, 2019
Louis Theodore, R. Ryan Dupont
There are two principal types of tubular vaporizing equipment used in industry: boilers and vaporizing exchangers (Kern 1950; Flynn et al. 2019). Boilers are directly fired tubular apparatus that primarily convert fuel energy into latent heat of vaporization. Vaporizing exchangers are unfired and convert the latent or sensible heat of one fluid into the latent, heat of vaporization of another. If a vaporizing exchanger is used for the evaporation of water or an aqueous solution, it is now fairly conventional to call it an evaporator. If it is used to supply the heat requirements at the bottom of a distilling column, whether the vapor formed be steam or not, it is labeled a reboiler. When not used for the formation of steam and not a part of a distillation process, a vaporizing exchanger is simply called a vaporizer. When an evaporator is used in connection with a power-generating system for the production of pure water or for any of the evaporative processes associated with power generation, it is a power-plant evaporator. When an evaporator is used to concentrate a chemical solution by the evaporation of solvent water, it is a chemical evaporator. Both classes differ in design. Unlike evaporators, it is the object of reboilers to supply part of the heat required for distillation and not a change in solution concentration, although a change generally cannot be avoided. Very often the term evaporator is also applied to a combination of several pieces of equipment, each of which can also be defined as an evaporator (Flynn et al. 2019).
Performance Assessment of Coal Fired Power Plant Integrated with Calcium Looping CO2 Capture Process
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2023
As shown in Figure 1, the cryogenic technology is employed to separate air into O2 product and N2 product. Feed air in ambient condition is firstly passing through the compressor, and then is cooled to 30°C via heat exchanger. The compressed air is split into two streams, 87% and 13%, after it is purified to remove the primary impurities such as H2O, CO2, and Ar via molecular sieve absorber. The two feed streams pass through the main heat exchanger where they are cooled against products leaving the Low-Pressure Column (LPC). One of the streams (87%) is sent to the High-Pressure Column (HPC) where nitrogen is separated at a pressure of about 5.6 bar. The other stream (13%) is expanded to 1.2 bar in the expander and then is sent to the LPC (Aneke and Wang 2015). The reboiler of the LPC and the condenser of the HPC are coupled by heat exchanger. The top nitrogen product from the HPC is condensed against the boiling oxygen in the reboiler of the LPC, and depressurized before being sent to the top of the LPC. The bottom rich oxygen liquid product from the HPC is also sent to the LPC after been depressurized. The liquid oxygen product and vapor nitrogen product, respectively, leave from the bottom and the top of LPC, and then they are warmed in the main heat exchanger.
Simulation of Thermosiphon Reboilers Using Wire Matrix Inserts at Lower Operating Range
Published in Heat Transfer Engineering, 2023
Yan Lu, Katharina Jasch, Stephan Scholl
The experiments were conducted in a vertical shell and tube heat exchanger E1 with three reboiler tubes, see Figure 1. The heat exchanger was made of stainless-steel SS 1.4571 with thermal conductivity of 15 W·m-1·K-1. The reboiler tube geometry was do,RT · s · = 20 mm · 2 mm · 1,500 mm. The temperatures at the reboiler tube inlet and outlet were measured by four-wire resistance thermometers (TMH Pt 100/A, tolerance ±0.15 K). At the shell side, steam supplied by a boiling thermostat E2 (GWK vacutherm vt06, power up to 6 kW) condensed on the outer wall. The boiling thermostat was operated with water, which allowed a heating temperature range from 46 °C to 96 °C. The pressure in the middle of the shell was measured by a pressure transmitter PIR205 (Keller PAA35XHTC with a measuring range of (0 … 1) bar and a precision of ±0.005 bar).
Soft-sensor models to estimate the efficiency of H2S removal from an oil refinery stream of nonphenolic sour water
Published in Chemical Engineering Communications, 2018
Deivid Jonathan Souza Barros, Emanuel Souza Barros, Everton Fernando Zanoelo
The stripper used to remove H2S is schematically shown in Figure 1(a). It consists of a tower with 20-valve trays, a thermosiphon reboiler, and a plate-type condenser. The stripped vapor stream entering the heat exchanger at the top of the tower is partially condensed in a way that the liquid leaving is readmitted into the column, while the gas rich in H2S and poor in NH3 is treated in a separate sulfur recovery unit. The column was designed to operate at an overall efficiency of 50% with sour water continuously admitted at the top tray. Saturated steam at 1780 kPa was used in the reboiler for heating. Mf, Tf, Mv, ΔTr, and ΔP were close to 11.1–20.8 kg s−1, 125–128°C, 1.4–2.8 kg s−1, 0–23°C, and 16–30 kPa, respectively. They were measured with flow transmitters (model 3051, accuracy ±1.8%, Emerson, St Louis, MO, USA), a temperature transmitter (model YTA110 with a K-type thermocouple, accuracy ±0.25°C, Yokogawa, Tokyo, Japan), and a gauge pressure transmitter (model EJA430A, accuracy ±0.065, Yokogawa, Tokyo, Japan).