RU2575650C2 - Method for sea water desalination by means of thin-film semiconductor thermoelectric cylinder-shaped thermal pump - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to methods for sea water desalination. Method for sea water desalination by means of thin-film semiconductor thermoelectric cylinder-shaped thermal pump includes application of preliminary heat exchange for heating sea water, intended for evaporation, due to discharge of heat from desalinated water and concentrated salt solution. Thin-film semiconductor thermoelectric cylinder-shaped thermal pump brings sea water to boiling by hot junction, taking heat from condensed steam by cold junction, working in mode of heat transmission intensifier.

EFFECT: invention makes it possible to increase energy efficiency of desalter.

1 dwg

Description

The invention relates to methods of desalination, in particular to the field of desalination of sea water.

A known method of desalination of sea water [1]. The working chamber in the form of a parallelepiped only through one of the four surfaces provides heat transfer, which affects the performance of the installation. In addition, the release of Joule heat during flow through the semiconductor branches of the thermal module leads to the fact that the parasitic energy costs of generating heat are more than three times the effect of cooling, which also reduces the energy-saving characteristics of the desalination plant.

The purpose of the invention is the elimination of these disadvantages by increasing energy efficiency.

This is achieved by the fact that the design of a cylindrical thin-film semiconductor thermoelectric heat pump allows, by changing the geometrical dimensions of the desalination plant, to equalize the flow rates of incoming sea water and flowing fresh water and brine, and the cross-sectional area of the pipeline for incoming sea water should be equal to the total area of the flowing fresh water and brine. Another advantage is that, unlike the parallelepiped-shaped working chamber, which has two lateral surfaces that are not involved in the heat exchange process [1], the cylindrical shape has no lateral faces and all surfaces participate in heat transfer, which significantly increases the desalination plant’s performance and allows it to be reduced dimensions. In addition, the use of thin-film p- and n-type semiconductor branches in a thermal module practically reduces their electrical resistance to zero and completely eliminates spurious Joule heat emissions. At the same time, the Peltier thermoelectric effect on heating and cooling is fully preserved, bringing the efficiency of the heat pump to almost 100%, which improves the energy-saving characteristics of the desalination plant as a whole.

In FIG. 1 shows the design of the device that implements the proposed method.

Sea water 1 enters the heat exchanger from the bottom up. A semiconductor thermoelectric heat pump of cylindrical shape 5 is designed to remove heat from fresh water 2 to sea water 1. A semiconductor thermoelectric heat pump of cylindrical shape 4 removes heat from concentrated salt solution 3 to seawater 1. At the top there is a semiconductor thermoelectric heat pump of cylindrical 6 which, by hot junction, brings seawater 1 to a boil, and by cold junction, it condenses steam 7 into fresh water 2.

The method is implemented as follows.

A cylindrical semiconductor thermoelectric heat pump 6 carries out the main process in a desalination plant: it boils seawater 1 and steam 7 condenses into clean water 2. The energy performance of a cylindrical 6 semiconductor thermoelectric heat pump in a desalination plant is highly efficient, since the temperature gradient between boiling sea water 1 and condensing steam 7 is practically negligible and does not require large energy costs during operation. In fact, a cylindrical semiconductor thermoelectric heat pump 6 intensifies the heat transfer process from condensed steam to boiling seawater 1. The cylindrical semiconductor thermoelectric pumps 4 and 5 work similarly, and there are no horizontal temperature gradients, and vertically vary from 20 ° C in the lower part to 100 ° C at the top. In this case, minimum energy costs are required for the operation of the desalination plant. The proposed design of the heat exchanger makes it possible to select almost all the heat from clean water 2 for transferring it to sea water intended for subsequent boiling, thereby reducing energy costs for the operation of the desalination plant. The dimensions of a semiconductor thermoelectric heat pump depend on the electrothermophysical parameters of the heat pump itself, fluid velocity, wall thickness, fluid volumes and heat transfer coefficients of the wall materials. Salt solution 3, which, moving downward, transfers heat through semiconductor thermoelectric heat pump of cylindrical shape 4 to sea water 1, which is supplied for desalination up.

The proposed design allows you to recover heat and improve the energy performance of the desalination plant as a whole. The outer walls of the desalination plant should consist of a heat-insulating material to reduce stray conductive transfer of thermal energy to the environment. The size of the desalination plant can vary widely while maintaining the basic condition: the temperature at the outlet of the desalination plant for clean water 2 and salt solution 3 should be practically equal to the temperature of sea water 1 fed to the desalination plant. To satisfy this condition, it is possible to increase the height of the desalination plant, reduce the rate of flowing clean water 2 and the concentration of saline solution 3, make all three chambers of the desalination plant thinner for liquids 1, 2, 3. The productivity of the plant depends on the energy performance of a cylindrical thermoelectric device 4, 5 , 6.

One of the applications of the desalination plant is the production of fresh water and concentrated solutions from any aqueous solutions, as well as the processing of wastewater from industrial enterprises. Desalination plant construction materials are environmentally friendly.

Literature

1. Thermoelectric desalination plant: US Pat. 2225843 ROS. Federation: IPC C02F 1/04. Ismailov T.A., Aminov G.I., Evdulov O.V., Yusufov Sh.A., Zarat Abdelkader; applicant and patent holder "Dagestan State Technical University". - declared. 11.11.2002, publ. 03/20/2004.

Claims (1)

The method of desalination of sea water using a thin-film semiconductor thermoelectric heat pump of a cylindrical shape, which consists in the fact that desalination of sea water uses preliminary heat exchange to heat sea water intended for evaporation, by removing heat from desalinated water and concentrated saline solution, characterized in that a thin film semiconductor thermoelectric heat pump of cylindrical shape by hot junction brings seawater to a boil, taking cold we heat the heat of condensed steam, working in the mode of heat transfer intensifier in order to increase energy efficiency.

Images