Method for preheating inflow water of membrane method seawater softening device

Abstract

The invention relates to a method for preheating inflow water of a membrane method seawater softening device, belonging to the technical filed of oilfield development and seawater desalination. The method comprises the following steps of: firstly, exchanging the heat between low-temperature seawater and produced water or drained strong brine of the membrane method seawater softening device in a primary heat exchanger, recovering the waste heat of the drained strong brine, exchanging the heat between the seawater undergoing primary preheating and produced water with crude oil separated in a secondary heat exchanger, continuing to increase the temperature of the seawater, leading the seawater undergoing two stages of preheating into the membrane method seawater softening device, and separating the seawater to obtain the product water; and collecting the drained strong brine of the membrane method seawater softening device, returning the drained strong brine back to the primary heat exchanger to preheat low-temperature inlet seawater, leading the strong brine into a strong brine drainage pipeline after releasing heat and cooling down, and leading the oilfield produced water into a produced water reinjection pump station pipeline after releasing heat and cooling down so as to realize the two-stage preheating of inflow water of the membrane method seawater softening device. The method has the advantages of simple principle, convenience for operation, reliable running, energy saving, environment friendliness and practical value.

Description

Technical field: [0001] The invention relates to a method for preheating the water intake of a membrane seawater softening device, in particular to a method for making the membrane seawater softening device normally run in winter through a two-stage preheating process, and belongs to the technical field of marine oilfield development and membrane seawater desalination . Background technique: [0002] The membrane flux of the membrane water treatment system is an important indicator of system design, and the system inlet water temperature is an important factor affecting the membrane flux. Under the condition of a certain operating pressure of the system, if the raw water temperature is too low, the water production of the system will be greatly reduced. For example, every time the temperature drops by 1°C, the flux of the reverse osmosis seawater desalination membrane will drop by about 4%. Winter in northern my country is cold, and the seawater temperature is low. For exa...

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Problems solved by technology

[0006] The purpose of the present invention is to overcome the shortcomings of the prior art, especially for the defects that the membrane water treatment system cannot operate normally in winter and the current situation of the waste heat of oilfield produced water and the utilization of high-temperature cooling water heat energy in the industrial production process. A method for effectively utilizing the thermal energy of oilfield produced water generated after oil-water separation in an oilfield or the thermal energy of high-temperature cooling water in industrial production processes for preheating raw seawater in membrane seawater softening and desalination systems

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