Energy-saving drying technology for porous media using liquefied DME gas

Adsorption Science & Technology

2008

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There is a growing need for the economical dewatering of highspecific-surface-area fuels containing large amounts of water, such as coal and sewage sludge. The principle underlying conventional dewatering methods is evaporation of the water content by heating the fuels to a high temperature, but this approach consumes a considerable amount of energy. The Central Research Institute of the Electric Power Industry (CRIEPI) has developed a method for the extraction of this water through the use of dimethyl ether (DME), which liquefies at ordinary temperatures under the influence of a slight pressure. In this method, the water content in the fuel is extracted into the liquefied DME for separation from the fuel. After dewatering, the DME is depressurised, and subsequently vaporised, thereby leaving the separated water. Dewatering with an input energy of only 1109 kJ/kg water under ordinary conditions has been demonstrated theoretically.

Section: Principle Of Dme Dewatering Technologymentioning

confidence: 94%

Super-Energy-Saving Dewatering Method for High-Specific-Surface-Area Fuels by Using Dimethyl Ether

Adsorption Science & Technology

2008

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“…By using liquefied dimethyl ether (DME) as an extractant, green crude was extracted directly from high-moisture natural microalgae without drying and cell wall disruption. This method was conceptualized from our previously established low-energy dewatering [13][14][15][16] and deoiling method [17][18][19], based on the following DME characteristics, namely (i) high affinity with oil and partial miscibility in water (ii) lower boiling point and stable pressure at normal temperature (iii) harmless and naturally decomposable [20,21].…”

Section: Introductionmentioning

confidence: 99%

Simple Extraction Method of Green Crude from Natural Blue-Green Microalgae by Dimethyl Ether: Extraction Efficiency on Several Species Compared to the Bligh-Dyer's Method

Linköping Electronic Conference Proceedings

2011

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Abstract:We proposed a simple, energy-efficient and environmental friendly method to extract green crude oil from microalgae by using dimethyl ether (DME). In this study, this method was tested on several species of natural blue-green microalgae. Consequently, the green crude was successfully directly extracted from highmoisture microalgae (78.2-93.4 % water content) with an extraction rate ranging from 9.9 to 40.1 % of the dry weight of the microalgae. The extraction yield of total green crude on these species by liquefied DME was compared to the widely-used Bligh-Dyer's method. The DME method almost achieved an extraction capacity approximately equivalent to the Bligh-Dyer's method. Furthermore, the dewatering properties of the proposed method on several species of wet microalgae, and the extraction efficiency were also investigated.

“…This method can be used for the efficient extraction of water (dewatering) from high-moisture coal at ordinary temperatures; thus, it can be used to increase the calorific value per weight of coal and make such fuels easy to use. Sub-bituminous coal and lignite, which are "porous fuels with a high specific surface area," can be easily dewatered using the DME dewatering process developed by the authors (1)- (3) , a part of the combustible component of the coal erodes and dissolves in liquefied DME. Therefore, lipophilic substances are believed to dissolve in liquefied DME.…”

Section: Introductionmentioning

confidence: 99%

Clean up Process for Oil-polluted Materials by Using Liquefied DME

Makino

2009

JEE

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The proposed technology is a new concept that aims at energy-efficient drying and cleanup for general purposes by the use of liquefied DME (dimethyl ether) gas. Large amounts of energy are required for the cleanup of the ground since the water contained in the soil hinders the extraction processes that use hydrophobic organic solvents. Therefore, we focus on the use of liquiefied DME, which is eco-friendly, as an extractant. The saturated pressure of DME is moderate-0.51 MPa at 20°C and 0.68 MPa at 30°C. Liquefied DME resolves high volume organic contaminants and water. Moreover, water can be easily separated from DME by flash distillation. This technology reduces the energy required for water-removal to half the latent heat of water. We almost completely removed water and other oily materials by using DME. DME was completely recycled and none of it remained in these materials. The world's first prototype of a DME deoiling/dewatering process is shown. The capacity of this system is 10 L. Because of the low normal boiling point (-25°C) of DME, it does not remain in the soil and it can thus be reused as an extractant. In this presentation, we show the general purpose deoiling and dewatering processes for several materials.