Countercurrent exchange

About: Countercurrent exchange is a research topic. Over the lifetime, 2255 publications have been published within this topic receiving 28687 citations. The topic is also known as: Countercurrent exchange.

Direct osmosis process for power generation using salinity gradient: FO/PRO pilot plant investigation using hollow fiber modules

Abstract: The phenomenon of osmosis is known for more than 150 years and involves the contact of a semi-permeable membrane with solutions of different salinity. The osmotic flux that permeates through the membrane can be used for electric power generation as a renewable source of energy. This process can be accomplished by means of the pressure retarded osmosis (PRO). This work consisted of the construction of a demonstrative FO/PRO power pilot plant. Assymetric polymeric cellulose acetate hollow fiber membranes were produced and conditioned in permeation modules. The pilot plant consists of three countercurrent flow hollow fiber modules connected in parallel. According to the modules and fibers dimensions, the membrane area per module can reach 1.5 m 2 that means a packing density of 1500 m 2 m −3 . The pilot scale enables the activation of a hydroturbine/generator device coupled to a 9-LEDs panel which can establish the technological and scientific bases for further industrial upscaling. A forward osmosis (FO) test using a MgSO 4 solution (0.8 M, π : 22 bar) and an intermittent PRO test using a NaCl solution (0.8 M, π : 37 bar) were performed, where the maximum osmotic flux values were 33 and 8 L m −2 h −1 , corresponding to an energy performance of 5 and 2 W m −2 , respectively. These values are comparable with most of the latest bench-scale FO membrane investigations.

Novel slab type spiral heat exchanger

Abstract: The present invention relates to a novel plate type spiral heat exchanger, which has the characteristics of a plate heat exchanger, a spiral plate heat exchanger, and a spiral shell tube heat exchanger, and is characterized in that the size is small, the heat exchanging efficiency is high, the countercurrent heat exchange can be operated, the requirement of heat exchange in low temperature difference is met, a modular structure filter is provided, and a novel heat exchanger is easy to disassemble and clean, the present invention is easy for modularization process and assembly production, and the production cost is low The present invention is particularly suitable for recycling of the after heat of bathing waste water and pre heating clean tap water in the process of household bathing, and more than 60 percent of waste heat can be effectively recycled, and the water heater power can be doubled in the condition of using lower cost and no energy consumption is added

Process for producing methanol

Abstract: This invention is directed to a process for producing methanol. The methanol product that is produced according to this invention is achieved with a high conversion of synthesis gas. The high conversion of synthesis gas is achieved by flowing a liquid layer across a plurality of catalyst beds countercurrent to the gas flow. The gas containing methanol product exiting each bed flows through the liquid layer. The liquid acts to extract methanol from the gas, as well as cool the gas.

An investigation into stratified co- and countercurrent two-phase flows

Abstract: This paper investigates theoretically and experimentally certain stratified co- and countercurrent two-phase flows in circular pipes that have not been studied adequately. The theoretical analysis produced semiempirical relationships based on the momentum-balance concept. These relationships were then experimentally evaluated with two fluid systems of significantly different density ratios. It is suggested that the equations that correlated these results can be accepted for general use. An example is presented for a certain natural-gas/condensate application.