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1.
An experimental study has been carried out on a continuously operated pilot fractional distillation column equipped with an external heat pump. The distillation column was a 15 cm internal diameter glass unit containing eleven single bubble cap plates. A methanol-water mixture was fed to the column. After operating the heat pumps with R114 as the working fluid, further experiments have been conducted with R11 as the working fluid. Plots of pressure against enthalpy, condensation pressure and latent heat of vaporization against condensation temperature and theoretical Rankine coefficient of performance against gross temperature lift and condensation temperature are presented for both R114 and R11. R11 has correspondingly higher theoretical Rankine coefficients of performance than R114. The experiments show that the actual coefficients are also higher for R11 than for R114. A maximum actual coefficient of performance of 5.3 was obtained using R11 as the working fluid with a gross temperature lift of 38.4°C. The experimental data for R11 were found to be reproducible during operation over a number of weeks. This showed that the relative thermal instability of R11 compared to R114 had not apparently affected the performance of the system.  相似文献   
2.
The problems in matching a heat driven heat transformer to a distillation process in heat pump assisted distillation are discussed. The performance of such a system is a function of the temperature difference across the distillation column. Plots are given of the calculated coefficients of performance against the temperatures of the top and bottom products. In addition plots are given of the calculated coefficients of performance against the generator temperature when the generator is independently heated. The percentage of energy saved is also plotted against coefficient of performance.  相似文献   
3.
Steady-state performance data have been obtained on a domestic sized engine-driven water-to-water heat pump. The optimum working fluid suction superheat for the system was found to be 12°C. Over a range of heat sink conditions, increasing the engine speed linearly increased the total heat prouduced by the unit. Similarly, over a range of heat source conditions, increasing the engine speed linearly increased the working fluid evaporation rate. To produce water at 80°C, the heat pump was designed to operate with a heat sink temperature of 70°C, but its efficiency was improved by operating with the heat sink at 55°C. With a heat sink temperature of 55°C the primary energy ratio of the unit was observed to vary from 0–85 to 1–16, over a range of heat source temperatures. Algorithms developed from the steady-state experiments were incorporated as control function subroutines in a microcomputer program. Using this program, the microcomputer was employed to control the heat pump outlet water temperature and the working fluid suction superheat. The control system was tested in a series of dynamic experiments and was found to operate effectively and achieved its control requirements. In certain tests, the transient time period was extended because the electrically-controlled expansion valve was too large for the system and created instability in the suction superheat.  相似文献   
4.
The problems in matching an external mechanical vapour compression heat pump to a distillation process in heat pump assisted distillation are discussed. There are four main design parameters to consider when selecting a working fluid for the heat pump, of which only two are independent. Various arrangements for imperfectly matched systems are presented, including the use of a two stage heat pump. A number of other factors which affect the choice of a heat pump assisted distillation system, including economic factors, are also considered.  相似文献   
5.
An experimental study has been carried out on a continuously operated pilot fractional distillation column equipped with an external heat pump. The distillation column was a 15 cm diameter glass unit containing eleven single bubble cap plates. A methanol-water mixture was fed to the column and the heat pump working fluid was R114. The actual coefficient of performance (COP)A of the heat pump increased with an increase in the mass flow rate of the working fluid. A maximum (COP)A value of 4–3 was obtained with a gross temperature lift of 41–3°C. The performance of two reciprocating compressors was compared. The experiments have shown that continuous heat pump assisted distillation using an external working fluid can greatly reduce the energy used in a distillation process. No control problems were encountered in the experiments.  相似文献   
6.
Individual response to a disaster situation is investigated by requiring subjects to describe what action they would take if faced with an impending bombing plane poison gas raid. For 34 Ss the disaster situation involved threat of death, for 33 Ss, only a mild, temporary incapacitation. Three patterns of action appear, evacuation, active defense, and encapsulation, with some probability that the tendency to take the safest path varies with the degree of threat. The willingness to assist others varies inversely as the degree of threat, while the saving of objects is more fundamentally associated with the mode of escape the individual takes than with the degree of threat. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
7.
A survey is made of the numerous possible ways to minimize the consumption of energy in fractional distillation. Distillation is a highly energy-intensive process in which the actual energy consumed is far greater than the theoretically calculated loss in available work. The methods considered for reducing energy consumption are classified as those which (i) do not require process modifications, (ii) require minor process modifications, (iii) make use of more than one column and (iv) make use of heat pumps.  相似文献   
8.
More than one hundred and fifty references for heat pump assisted distillation systems have been listed and classified under the following categories: heat pump assisted distillation (1) with an external working fluid, (2) using one of the distillation components as the working fluid, (3) overall assessments and (4) experimental data.  相似文献   
9.
Experiments have been carried out to determine the effect of absorber reflux on the performance of a water-lithium-bromide absorption cooler. The reflux ratio was varied for two mass flow rates of solution leaving the absorber and two absorber temperatures. It has shown that absorber reflux can be used to decrease both the temperature and the concentration in the generator. The coefficient of performance and heat loads tend to have optimum values at a particular reflux ratio.  相似文献   
10.
It was hypothesized that people who valued themselves highly (high self-esteem) should fear death more than those who do not, and what these people should fear most about death is the cessation of those activities in which they are greatly involved. These attitudes towards death should vary with such demographic variables as age, sex, social class, religion, and marital status. The data support the hypotheses. From Psyc Abstracts 36:04:4HJ05D. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
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