Chembrane Engineering and Technology Inc.

Yinchuan, China

Chembrane Engineering and Technology Inc.

Yinchuan, China

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Zhang Z.-Y.,Tianjin University | Hao X.-G.,Tianjin University | Zhao J.-M.,Tianjin University | Qin Y.-J.,Tianjin University | And 4 more authors.
Gao Xiao Hua Xue Gong Cheng Xue Bao/Journal of Chemical Engineering of Chinese Universities | Year: 2016

Removal of ammonia from aqueous solutions using a dual-hollow fiber membrane contactor (which contains two sets of hydrophobic microporous hollow fibers) was investigated, and a theoretical model was developed to simulate the experimental results. The influence of various experimental parameters on the performance of the new membrane contactor was studied and compared with traditional membrane contactors under similar operation conditions. Experimental results show that the concentration of the by-product (ammonium sulfate solution) obtained by the new contactor is 29% higher than that from the traditional one, due to the osmotic distillation reducing effect. When the hydrogen ion molar flow rate in the stripping solution is 1.2 times lower than that of ammonia in the feed solution, the overall mass transfer coefficient K of the new contactor is >6 times higher than that of the traditional one. This result indicates that the new contactor overcomes the obvious shell mass transfer resistance caused by non-ideal flow in the traditional module. The long-term experiment lasting 600 days using pretreated landfill leachate as feed shows that the potential working life of the new contactor is much longer. © 2016, Editorial Board of “Journal of Chemical Engineering of Chinese Universities”. All right reserved.


Liu J.,Tianjin University of Technology | Qin Y.,Chembrane Engineering and Technology Inc. | Li P.,Tianjin University of Technology | Zhang K.,Tianjin University of Technology | And 2 more authors.
Journal of Chemical Technology and Biotechnology | Year: 2015

BACKGROUND: A major cost in acid-catalysed hydrolysis of biomass to fermentable sugars is the consumption of acid itself. In this study, a combined process was developed in which the acid and sugar in the hydrolysate were separated using an acid retardation process and then the dilute aqueous product streams were concentrated using a continuous-effect membrane distillation (CEMD) process, thus acid could be reused as catalyst. RESULTS: The recovery rate of sugar was as high as 94.3-99.2% while the recovery rate of sulfuric acid was 92.4-98.9%. The eluents were further concentrated using the CEMD process. When a solution of 2wt% sulfuric acid was concentrated to c. 40wt%, the maximum value of permeation flux (Jw) and gained output ratio (GOR) was 6.20Lm-2h-1 and 15.50, respectively. Meanwhile, the dilute aqueous sugar solution obtained from corn stover was concentrated 20-fold to a final concentration of c. 497.6gL-1 using the CEMD process with a final GOR of 5.5. CONCLUSION: The combination of acid retardation and CEMD is suitable for the production of sugar, further purification and concentration of eluents; the sugar solution can be used for fermentation and acid solution can be reused as catalyst. © 2015 Society of Chemical Industry.


Qin Y.,Chembrane Research and Engineering Inc. | Liu R.,Tianjin University | Li X.,Tianjin University | Liu L.,Chembrane Engineering and Technology Inc. | Zhang Y.,Chembrane Engineering and Technology Inc.
AIChE 2012 - 2012 AIChE Annual Meeting, Conference Proceedings | Year: 2012

It is well known that hydrochloric acid (HCl) is usually used as pickle liquor to remove surface oxide in a steel production industry. When pickling cannot be accomplished effectively and the quality of the treated metal surface deteriorates, the pickle liquor is discharged from the pickling tank, and the pickling tank is replenished with fresh acid solution. According to the data provided by the World Steel Association in 2011, the total world crude steel production was 1,490.1 million tonnes. And about 60 kg of spent pickle liquor was generated with the production of each ton of steel, and thus annual emission of spent pickle liquor was up to several million tons. As an example, 1000 ton of pickle liquor is being produced daily in a steel plant in north China, which contains 7% HCl and 15% FeCl2. The spent pickle liquor usually contains 2-8 wt% hydrochloric acid and is considered a hazardous waste. The spent pickle liquor from steel processes is usually neutralized with lime and disposed in a landfill, which results into the following problem: high-salinity wastewater and sludge volume, the remaining salt residue processing difficulties, and most importantly, the acid unrecoverable. Therefore, there is an urgent need to recover and enrich hydrochloric acid to achieve economical and ecological benefits. Since the 1960s, hydrochloric spent pickling liquor is often treated in a hydrochloric acid regeneration system such as ion-retardation, diffusion dialysis and electro-dialysis, which recovers some of the hydrochloric acid and ferric oxide. Nevertheless, these regeneration processes produce lots of dilute hydrochloric acid solution. Thus, there still needs a novel and efficient technology to concentrate the recovered dilute HCl solution for further use. In the last few years, numerous studies have been performed to test the application of membrane distillation for concentrating dilute HCl solution. However, the high thermal energy consumption of the traditional MD process is one of the biggest barriers in its industrialization. In the present study, multiple-effect membrane distillation (MEMD) based on AGMD module with function of internal heat recovery has been developed. This kind of MEMD process combines the advantages of MD process and conventional MSF process, avoids the disadvantages of MSF such as evacuation operation, and can provide a high PR value. The effects of feed-in concentration, cold feed-in temperature (Tc), hot feed-in temperature (Th) and feed-in volumetric flow rate (F) on the performance of MEMD process were studied. The permeation flux (N) and energy efficiency, performance ratio (PR), and the average selectivity of water over HCl (βavg) are the most important indicators for module performance evaluation. N indicates the productivity of this device; PR (performance ratio) is usually used to determine the thermal efficiency of evaporation-based process, which is defined as the amount of latent heat needed for evaporation of the produced water and the amount of heat provided to the system from an external energy source; βavg is represents the measure of the preferential transport of water. The results showed that MEMD process could be used successfully for concentrating dilute HCl solution with the advantage of energy saving. The experimental data indicated that all N, PR and βavg decreased with the increase of feed concentration. When the feed concentration was below 12 wt%, PR could achieve 6.0∼9.6, and βavg was about 10~190. As the concentration of HCl achieved 18 wt%, the values of PR and βavg were still about 4.4 and 2.3, respectively. However, βavg sharply decreased to a value around 1.0 when feed was further concentrated. It is also found that there exists trade-off phenomenon between N, PR and βavg under experimental ranges, that is, the maximum N will be obtained with high temperature Th, low temperature Tc and high flow rate F while the maximum PR is obtained with high temperatures Th and Tc, as well as low flow rate F. the lowest βavg will be obtained with low temperature Th, low temperature Tc and low flow rate F. During an operational stability test lasting for 30 days, the performance of MEMD modules was kept in good condition.


Qin Y.,Chembrane Research and Engineering Inc. | Wu Y.,Chembrane Research and Engineering Inc. | Liu L.,Chembrane Engineering and Technology Inc. | Cui D.,Chembrane Engineering and Technology Inc. | And 6 more authors.
10AIChE - 2010 AIChE Annual Meeting, Conference Proceedings | Year: 2010

Membrane distillation (MD) is a separation method in which a nonwetting, microporous membrane is used with a liquid feed phase on one side of the membrane and a condensing, permeate phase on the other side. Separation by membrane distillation is based on the relative volatility of various components in the feed solution. The driving force for transport is the partial pressure difference across the membrane. Separation occurs when vapor from components of higher volatility passes through the membrane pores by a convective or diffusive mechanism. Membrane distillation systems can be classified broadly into three categories: direct-contact membrane distillation (DCMD), vacuum membrane distillation (VMD) and air-gap membrane distillation (AGMD). Potential advantages of membrane distillation over traditional evaporation processes include operation at ambient pressures, lower temperatures as well as ease of process scale-up, and avoid of corrosion as a result of inertness of hydrophobic polymer membrane material. Although MD has been extensively and intensively studied for nearly 40 years, it is still not use in commercial scale. As matter of a fact, MD is with extremely low thermal efficiency, even if the researcher on MD always declaimed that MD only need a heat resource with low temperature. For example, when VMD occurs, nearly 1 ton of pure water can be produced when 1 ton of steam is used to heat a cold feed; when DCMD occurs, only 0.3 - 0.6 ton of pure water can be produced when 1 ton of steam is used to heat a cold feed. As a comparison, when traditional multi-effect distillation (MED) or multi-stage flash (MSF) is used for desalination, 1 - 15 ton of pure water can be produced when 1 ton of steam is used to heat a cold feed. Therefore, if a term of performance ratio (PR) is used to characterize the thermal energy utility, while the value of PR for MED and MSF is between 1 - 15, unfortunately the value for traditional MD process is only 0.3 - 1.0. Another problem with MD is wetting or fouling of microporous membrane surface, which leads to the decrease of permeate flux and leakage; leakage further leads to the contamination of the permeate product by the impurities in the feed. Wetting or fouling is a more grievous problem in a DCMD or VMD process, since the intimate contact of the permeate with the membrane in DCMD or the large trans-membrane pressure difference in VMD. On the other hand, the scale AGMD module was rarely reported in literature. Recently, MD process with multi-effect characteristics were reported by using hollow fiber or flat sheet membrane, even though the concept of multi-effect membrane distillation was not directly used as a term. In the present study, multi-effect membrane distillation (MEMD), a new membrane distillation process, has been developed, which combines the advantages of both membrane distillation (MD) and multistage flash (MSF) by equipping air gap membrane distillation (AGMD) with internal heat recovery. A novel separation device in the form of hollow fibers is fabricated to test its separation performance, which is identified as MEMD module. Several MEMD modules with different configurations were fabricated in our company since 2005. The water vapor flux (J) and energy efficiency in term of performance ratio (PR) and thermal efficiency (η) are the most important indicators for evaluation of DCMD module performances. J indicates the productivity of the membrane module; PR tells how much energy is recovered by internal configuration and η shows how much energy is lost due to conduction according to the second law of thermodynamics. Experiments were conducted using aqueous solution of salt NaCl to investigate the influences of operating variables including inlet temperatures of two sets of different fibers and flow rate on these above three performance parameters. The value of J was usually 3 - 10 kg/m2hr; the value of η was usually more than 0.9; and the value of PR varied between 3 and 15, which mainly depended on the characteristics of the hollow fiber used, and salt species and concentration, and the operation temperature. Flux decline together with reduction of PR and the decrease of ç were observed with the increased salt concentration (up to about 220g/L) mainly because of its high viscosity and reduction of water vapor pressure with the increase of salt concentration. Even so, the value of J and PR at a NaCl concentration of 20wt% is 50% of the value at a NaCl concentration of 3wt%. Such a MEMD operation for further concentration of 20% salt solution was operation at mild temperature (less than 100°C) and ambient pressure. It must be noted that it is impossible to further concentrate a feed of 20% by reverse osmosis, and high temperature and evacuation must be used when MED or MSF is used for the further concentration of 20% salt solution. Therefore, MEMD can be potentially used to further concentrate the brine by-produced during the routine desalination plant by using RO, MSF, or MED, to produce drainable water and salt. Since 2006, MEMD has been tested in pilot-scale for desalination of real seawater and for the deep concentration of bring from the RO unit for the treatment of wastewater drained from a refinery plant. No leakage or decline of operation performance was observed during the 4-month long test period. MEMD can also used to separate volatile semi-volatile and non-volatile solutes from their aqueous solution. The system tested was aqueous solution of the following solutes: variety of non-volatile salts, sugars, urea, sodium hydroxide, sulfuric acid, hydrochloric acid, hydrofluoric acid, hydrobromic acid, phosphorous acid, phosphoric acid, nitric acid, acetic acid, chloroacetic acid, dichloroacetic acid, oxalic acid, succinic acid, glutaric acid, adipic acid, fluosilicic acid, ammonia, alkyl monoamines with low molecular weight, aminoglucose, amino acids, glycerol, ethylene glycol, propylene glycol, formaldehyde, ethanol, acetone, formamide, dimethylformamide, dimethyl sulfone, solfulane, hydrogen peroxide, hydrazine hydrate, ethanolamine, diethanolamine, diamines or polyamines, ammonium carbonate, ammonia sulfide, or several practical aqueous solutions containing two or three solutes, such as hydrochloric acid + glucose, hydrochloric acid + aminoglucose, sulfuric acid + glycerol, phosphorous acid + formaldehyde, fluosilicic acid + hydrofluoric acid + nitric acid, nitric acid + oxalic acid, hydrochloric acid + ferrum(II) chloride, and so on. The currently performing pilot-scale test is the concentration of fruit juices, and the water production from the wastewater streams strained from the deionized water production unit in a power plant. The test results demonstrated MEMD can effectively concentrate aqueous solution of non-volatile salt, most of inorganic acids, non-volatile or semi-volatile organic compounds with a boiling point of more than 180 °C, or solutes with extremely strong association with water such as hydrochloric acid, hydrofluoric acid, hydrobromic acid, hydrazine, formaldehyde from their aqueous solution. However, MEMD does not provide a high selectivity for aqueous solution containing a volatile organic compounds or a semi-volatile compound with a boiling point less than 180 °C. The techno-economic analysis demonstrated that MEMD process is a strong competitor for desalination or concentration of aqueous solutions to RO, MSF and MED.


Yao K.,Tianjin University | Qin Y.,Chembrane Research and Engineering Inc. | Liu L.,Chembrane Engineering and Technology Inc. | Yuan Y.,Tianjin University | Liu D.,Chembrane Engineering and Technology Inc.
10AIChE - 2010 AIChE Annual Meeting, Conference Proceedings | Year: 2010

Bioethanol production is generally regarded as a promising alternative way to substitute the traditional petroleum-based liquid fuels. Lignocelluloses, which are abundant in nature and independent of the market for food and cattle feed, are preferable to conventional starch or sugar containing feedstocks as raw materials for large scale production. The reported concentration of fermentable sugars in the cellulosic hydrolysate prior to fermentation is relatively low because of some process restraints during hydrolysis to obtain high sugar yield. However, in order to decrease the size of footprint of the entire processing plant and also energy consumption in downstream separation/purification, the feed to fermentation requires high concentration of sugars. To resolve this contradiction, an economically efficient and well performed preconcentration unit is necessary to added between the hydrolysis and fermentation step. In the present study, multi-effect membrane distillation (MEMD), a new membrane based distillation process, has been developed, which combines the advantages of both membrane distillation (MD) and multistage flash (MSF) by equipping air gap membrane distillation (AGMD) with internal heat recovery. A novel separation device in the form of hollow fibers is fabricated to test its separation performance, which is identified as MEMD module. The water vapor flux (J) and energy efficiency in term of performance ratio (PR) and thermal efficiency (η) are the most important indicators for evaluation of module performance. J indicates the productivity of the membrane module; PR tells how much energy is recovered by internal configuration and η shows how much energy is lost due to conduction according to the second law of thermodynamics. Experiments were conducted using the dilute salt aqueous solution as a tracer to investigate the influences of operating variables including inlet temperatures of two sets of different fibers (Th:70-90°C and Tc: 25-45Å°C) and flow rate (F:16-48L/h) on these above three performance parameters. During the experiment, no leakage is detected and the distillate is of good quality which means the separation efficiency is almost 100%. It is found that the most important determinant parameter is flow rate and there exists trade-off phenomenon between flux (J) and energy efficiency (PR and η) under experimental ranges, that is, the maximum flux will be obtained with high temperature Th, low temperature Tc and high flow rate F while the maximum PR or η is obtained with high temperatures Th and Tc, as well as low flow rate F. Two kind of modules with different hollow fiber diameter and length (M1 and M2 fabricated in Chembrane, China) are also compared. Response surface method (RSM) is carried out to build an empirical quadratic model for prediction of the separation performance and optimization, which agrees well with the experimental results. In general, the typical measured water permeation flux in this study is around 2.0 - 9.0L/m2 h and the value of PR is 4 - 12 and the value of η is 0.80 - 0.95. Flux decline together with reduction of PR and the decrease of η were observed with the increased sugar concentration (up to about 500g/L) mainly because of its high viscosity and there existed slightly differences among three sugars (glucose, xylose and sucrose). But it should be noted that the performance of this new device is still appreciated even at higher concentration. This MEMD process was successfully applied in preconcentrating sucrose aqueous solution from 150g/L to 600g/L and also obtains 14-fold of initial concentration of model cellulosic hydrolysate (mixture of glucose and xylose aqueous solution) in a very efficient way.


Liu R.,Tianjin University | Qin Y.,Tianjin University | Li X.,Tianjin University | Liu L.,Chembrane Engineering and Technology Inc.
Frontiers of Chemical Science and Engineering | Year: 2012

Multiple-effect membrane distillation (MEMD) using a hollow fiber-based air-gap membrane distillation module was experimentally examined for concentrating dilute aqueous hydrochloric acid. The effects of the hot and cold feed-in temperatures, and the feed-in volumetric flow rates on the performance of the MEMD process were studied. The performance was evaluated using the performance ratio (PR), the average selectivity of water over HCl (β avg) and the permeation flux (N). Two types of porous fibers made from polypropylene were used to fabricate the MEMD modules. The experimental data indicated that hollow fibers with high porosity were preferred for the MEMD process. The PR, β avg and N all decreased as the feed concentration increased. When the feed concentration was below 12 wt-%, the PR was 6. 0-9.6 and β avg was 10-190. When the concentration of HCl reached 18 wt-%, the PR and β avg were about 4.4 and 2.3, respectively. However, β avg sharply decreased to around 1.0 when the feed was further concentrated. During an operational stability test that lasted for 30 days, the performance of the MEMD modules remained good. © 2012 Higher Education Press and Springer-Verlag Berlin Heidelberg.


Li H.,Tianjin University | Qin Y.,Tianjin University | Qin Y.,Chembrane Engineering and Technology Inc. | Cui D.,Chembrane Engineering and Technology Inc. | And 3 more authors.
Chinese Journal of Environmental Engineering | Year: 2014

The experiments were carried out to investigate the supported gas membrane-based separation process for removal/recovery of ammonia from landfill leachate by using industrial scale membrane modules made from microporous hydrophobic polypropylene hollow fibers. The effects of pretreatment technologies such as foam separation and lime flocculation-coagulation on surface tension and COD of the landfill leachate were examined. The effects of feed characteristics and operational factors on the overall mass transfer coefficient and the long-term operational stability were also investigated. The experimental results showed that the pretreatment steps could significantly increase the surface tension of the landfill leachate, and could greatly reduce its chroma and COD value. More than 99% of ammonia in the landfill leachate could be removed effectively by this process with configuration of two membrane modules in series under the following experimental conditions: feed flow rate of 100 L/h, feed ammonia nitrogen concentration of 1000~3000 mg/L, acidic-stripping-solution flow rate of 200 L/h, sulfuric acid concentration of 6%~10% and temperature of 20~30°C. Meanwhile, an aqueous solution of 10%~15% ammonium sulfate was obtained as a by-product. The pilot-scale demonstration test was operated for two months in which it showed great operational stability and reliability.


Wang B.,Tianjin University | Qin Y.,Tianjin University | Qin Y.,Chembrane Engineering and Technology Inc. | Cui D.,Chembrane Engineering and Technology Inc. | And 2 more authors.
Chinese Journal of Environmental Engineering | Year: 2014

Multiple-effect membrane distillation (MEMD) process, based on hollow fiber air-gap membrane distillation module with internal latent-heat recovery, was used to recover dimethyl sulfoxide (DMSO) from fiber wastewater containing low concentration of DMSO. Effects of cold feed-in temperature, heated feed-in temperature at the membrane entrance, feed-in flow rate and feed-in concentration on the performance of MEMD were experimentally investigated, which was indicated by permeate flux (J), gained output ration (GOR), selectivity of H2O/DMSO (α) and recovery rate of DMSO (R). The experimental results showed that the fiber wastewater containing DMSO could be successfully concentrated to a final concentration of 200~300 g/L by using MEMD process. The maximum value of GOR and α could reach 12.4 and 76, respectively for the initial feed concentration. All the values of J, GOR and α decreased as the feed concentration increased, but their values could still achieved 3.74 L/(m2·h), 7.1 and 32.1, respectively for the feed concentration of 200 g/L. R basically unvaried with the variation of operating parameters, which maintained above 99.6%. When the feed concentration was up to the range of 150~300 g/L, the content of DMSO in the distillate was not negligible, and it should be further treated with the MEMD process. The performance of MEMD process went well during a long operational stability test lasted for 30 days. This study demonstrated that MEMD was a highly energy-effective process for efficient recovery DMSO from fiber wastewater.


Liu J.,Tianjin University | Qin Y.,Tianjin University | Qin Y.,Chembrane Engineering and Technology Inc. | Li P.,Tianjin University | And 3 more authors.
Journal of Chemical Technology and Biotechnology | Year: 2016

BACKGROUND: A major cost in acid-catalysed hydrolysis of biomass to fermentable sugars is the consumption of acid itself. In this study, a combined process was developed in which the acid and sugar in the hydrolysate were separated using an acid retardation process and then the dilute aqueous product streams were concentrated using a continuous-effect membrane distillation (CEMD) process, thus acid could be reused as catalyst. RESULTS: The recovery rate of sugar was as high as 94.3-99.2% while the recovery rate of sulfuric acid was 92.4-98.9%. The eluents were further concentrated using the CEMD process. When a solution of 2wt% sulfuric acid was concentrated to c. 40wt%, the maximum value of permeation flux (Jw) and gained output ratio (GOR) was 6.20Lm-2h-1 and 15.50, respectively. Meanwhile, the dilute aqueous sugar solution obtained from corn stover was concentrated 20-fold to a final concentration of c. 497.6gL-1 using the CEMD process with a final GOR of 5.5. CONCLUSION: The combination of acid retardation and CEMD is suitable for the production of sugar, further purification and concentration of eluents; the sugar solution can be used for fermentation and acid solution can be reused as catalyst. © 2015 Society of Chemical Industry © 2016 Society of Chemical Industry.

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