Industrial-scale Tests Research Articles

Distinguishing the vertical air-staging low-NOx function of secondary air for suspension combustion within an industrial-scale coal-fired reversal grate furnace

The numerous coal-fired grate furnaces in China, which were designed to partition primary air on the grate and arrange secondary air in the freeboard for air-staging combustion, suffered from poor burnout and high NOx. However, secondary air was conventionally closed or set at marginal openings in real operations and no investigation was reported to explain why. Upon these off-design secondary-air circumstances, industrial-scale tests and modeling investigations were performed for a 75 t/h coal-fired reversal grate furnace at secondary-air ratios of 0 %, 3 %, 6 %, 10 %, and 16 %, respectively. The primary aims were to (i) uncover its combustion and NOx formation characteristics with varying secondary air and (ii) confirm whether secondary air acted on a real air-staging function in reducing NOx. Flow-field deflection and asymmetric combustion were found in the furnace, with the upward gas entirely deflecting towards the rear side. The front-half furnace was filled with a large but weak recirculation zone without effective combustion, acting on a huge dead zone to waste the furnace-space utilization. With increasing the secondary-air ratio, the upward gas deflection deteriorated continuously. Layer combustion worsened while suspension combustion first strengthened and then weakened. NOx emissions displayed an ascent-to-descent trend. Carbon in slag raised while carbon in fly ash decreased. Among the five case setups, the 0 % setting (i.e., fully closing secondary air) exhibited the lowest NOx emissions and burnout loss. Compared with the habitual 6 % setup, fully closing secondary air not only reduced NOx emissions by 22 % but also improved a little burnout. These trends meant that opening secondary air only strengthened suspension combustion for burning well fly ash while raised both NOx and total burnout loss. Secondary air thus failed to role as an air-staging function in reducing NOx.

Effect of the coal-spreading air on airflow and low-NOx combustion within a 75 t/h coal-fired grate furnace

Coal-fired grate furnaces equipped with coal throwers, which conventionally own a low-NOx combustion framework consisting of (i) the partitioned primary air for the horizontal air staging on the grate and (ii) the coal-spreading air and secondary air for the vertical air staging in the freeboard, actually suffer from poor burnout and apparently high NOx emissions at habitual operations. While comprehensive investigations on the in-furnace airflow, coal combustion, and NOx formation, which are devoted to first explaining and then improving these problems, are absent up to now. In order to unveil the airflow, combustion, and NOx emission characteristics within a 75 t/h coal-fired reverse grate furnace, evaluate its coal-spreading air impact on the low-NOx combustion performance, and determine an appropriate coal-spreading air ratio for improving the furnace performance, both industrial-scale tests and numerical simulations were performed at the coal-spreading air ratios of 2 %, 4 %, 6 %, and 8 %, respectively. The flow-field deflection and asymmetric combustion appeared in the upper furnace, with the upward gas deflecting towards the rear-wall side and the front-half furnace part dominated by a weak recirculation zone without effective combustion. With increasing the coal-spreading air, problems of the flow-field deflection and asymmetric combustion aggravated. The combustion intensity weakened in the layer combustion zone while displayed an increase-to-decrease trend in the suspension combustion zone. In terms of indexes related to the furnace performance, burnout rate decreased continuously, and NOx emissions initially raised but then decreased. A comprehensive consideration of the coal-spreading requirement via air, flow-field symmetry, low-NOx combustion, and burnout suggests that a 2 % coal-spreading air ratio should be preferred, where NOx emissions and burnout loss were gained at 249 mg/m3 (6 % O2) and 5.75 %, respectively. It reduced NOx emissions by 49 % while raised slightly burnout loss, as compared with the corresponding levels of 486 mg/m3 and 5.4 % at the habitual case. These results not only negate the air-staging function of the coal-spreading air but also highlight the novelty of this work.

A Systematical Review of the Largest Alkali-Surfactant-Polymer Flood Project in the World: From Laboratory to Pilots and Field Application

Summary This paper presents a systematical review of the largest alkali-surfactant-polymer (ASP) flood project in the world, applied to the largest oil field in China. First, reservoir and fluid characteristics are highlighted. Next, project history is summarized, including laboratory studies, pilot tests, industrial-scale tests, and fieldwide application. Third, typical ASP flooding performance and reservoir management measures from more than 30 years’ experience are presented. In addition, performances of ASP flood and polymer flood in the same field, which is also the largest project in the world, are compared. The Lamadian-Saertu-Xingshugang (La-Sa-Xing) Field in the Daqing Field Complex (including the La-Sa-Xing Field and three smaller satellite fields) is the largest oil field in China. The Upper Cretaceous Saertu-Putaohua-Gaotaizi reservoir has an average porosity of 25% and average permeability of 610 md. The reservoir consists of more than 100 flow units with an average gross and net thickness of 1,377 ft and 394 ft, respectively, and is characterized by significant heterogeneity, both vertically and laterally. The reservoir lies at a depth of 2,566–2,585 ft true vertical depth (TVD), with original reservoir pressure of 1,534–1,740 psi and a reservoir temperature of 113–122°F. Crude oil has an API gravity of 33° and a viscosity of 9 cp at reservoir conditions. The discussed ASP flood project mainly targets high-quality reservoir sands. The field was brought on-stream in 1960 with immediate waterflood. Crossflow and water breakthrough became common issues during water injection, calling for a suitable enhanced oil recovery (EOR) method. The Saertu-Putaohua-Gaotaizi reservoir features favorable conditions for ASP flood, such as temperature, viscosity, permeability, and formation water salinity (7000 mg/L). In addition, the heterogeneous reservoir (permeability variation coefficient of 0.6–0.8) is suitable for ASP flood. ASP flood was studied in the laboratory from 1987 to 1993, followed by five small-scale pilots from 1994 to 1999, all being successful with incremental recoveries of ~20% stock tank oil initially in place (STOIIP). As a result, industrial-scale tests were conducted from 2000 to 2007, resulting in substantial improvement in production from ~4,000 BOPD to greater than 19,000 BOPD. Encouraged by those successes, the ASP project was expanded to fieldwide since December 2007, which is the largest ASP flood project in the industry worldwide. By 2021, daily oil production by ASP flood had reached 96,000 BOPD through 4,825 producers and 4,825 injectors. The actual average incremental recovery factor is 20% over waterflood and 8–10% over polymer flood, resulting in ultimate recovery factor of >60%. Zonal injection and profile modification are effective measures to further improve sweeping efficiency. Scaling is the major challenge during the operation of ASP flood, which is mitigated or remediated by adopting weak alkali ASP, progressive cavity pumps (PCP), scale inhibitor treatment, and fracturing stimulation on damaged wells. As of 2022, oil production by ASP flood is still ongoing at 88,635 BOPD, accounting for 39.9% of total field production. The world’s largest ASP flood project in the La-Sa-Xing Field proved the fieldwide applicability of ASP flood, both technically and economically. The effective reservoir management measures and lessons learned from more than 30 years’ experience provide valuable experiences for large-scale ASP flood projects in the industry.

Study Reviews Largest ASP Project From Laboratory to Pilots and Field Application

_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 215058, “A Systematic Review of the Largest ASP Flood Project in the World: From Laboratory to Pilots and Field Application,” by Yunan Wei, SPE, Xiaoguang Lu, SPE, and Jianhong Xu, SPE, C&C Reservoirs, et al. The paper has not been peer reviewed. _ The complete paper presents a systematic review of the largest alkaline-surfactant-polymer (ASP) flood project in the world, applied in the largest oil field in China. First, reservoir and fluid characteristics are highlighted to understand heterogeneity of the reservoir. Next, project history is summarized, including laboratory studies, pilot tests, industrial-scale tests, and fieldwide application. Finally, typical ASP flood performance and reservoir management measures from over 30 years of experience are presented. Performances of ASP flood and polymer floods in the same field also are compared.​​​​ Introduction In the La-Sa-Xing Field, ASP flooding was studied in the laboratory from 1987 to 1993 and followed by five small-scale pilots from 1994 to 1999, all successfully achieving incremental recoveries of approximately 20% stock-tank oil initially in place (STOIIP). As a result, industrial-scale pilots were conducted from 2000 to 2007, resulting in increased production by ASP flooding from 3,887 to greater than 19,000 BOPD in 2007. Fieldwide ASP expansion was launched in December 2007. By 2021, the ASP-flooded blocks registered a STOIIP of 1.9823 billion bbl. Daily production was approximately 96,000 BOPD through approximately 9,650 wells. Average incremental recovery factor was 20% STOIIP with waterflooding and 8% with polymer flooding, providing an ultimate recovery factor of 60%. Cumulative oil production by ASP flooding had reached 316 million bbl by 2021, making it the largest ASP flooding project in the world. Geological Background and Reservoir Characteristics The La-Sa-Xing Field is in the north of the Songliao Basin of northeast China, comprising the majority of the Daqing field complex. The field was placed onstream in 1960. The hydrocarbon-bearing reservoir has a gross thickness of 1,377 ft and a net thickness of 394 ft. Net pay averages 150 ft. Initial reservoir pressure ranges from 1,523 to 2,585 psi. Reservoir temperature varies from 113 to 122°F. Crude oil has an API gravity of 33°, a viscosity of 8.5–10.3 cp at reservoir conditions, an initial gas/oil ratio of 258 scf/STB, and a bubblepoint pressure of 1,291 psi. Formation water salinity is 7000 mg/L. Reservoir rock initially shows water or weak oil wettability. Depending on permeability, three types of reservoir sand (Type I, Type II, and Type III) have been identified. Currently, ASP flooding is mainly applied to Type I sand, with partial application to Type II Sand.

Industrial Scale Direct Liquefaction of E. globulus Biomass

This work presents the study of Eucalyptus globulus bark and sawdust direct liquefaction. Laboratory scale experiments were carried out to assess the impact of several variables on the reaction yield and the sugar content of the bio-oil. These variables were the biomass type and concentration, the solvent, and the reaction time. The results show that E. globulus sawdust presented the highest yields (>95%), but the highest sugar content after water extraction was obtained for E. globulus bark (~5.5% vs. 1.2% for sawdust). Simultaneously, industrial-scale tests were carried out at the ENERGREEN pilot plant using the same reaction variables, which resulted in reaction yields of nearly 100%. The reagents and raw materials used, as well as the products obtained (bio-oil, reaction condensates, polyols, and sugar phases) were characterized by elemental analysis, infrared spectroscopy, thermogravimetry, and high-performance liquid chromatography with mass spectrometry. The heating value of the bio-oils is higher than the original biomass (higher heating value of E. globulus sawdust bio-oil 29 MJ/kg vs. 19.5 MJ/kg of the original E. globulus sawdust). The analyses of the bio-oils allowed us to identify the presence of high-added-value compounds, such as levulinic acid and furfural. Finally, a study of the accelerated aging of liquefied biomass showed that the biofuel density increases from 1.35 to 1.44 kg/dm3 after 7 days of storage due to the occurrence of repolymerization reactions.

Green industrial scale production of inorganic artificial stone from low calorific value coal ashes enhanced by physical resonant activation

Low calorific value coal fly ash and boiler slag with low silicon and aluminum content, low cementitious activity, is difficult to be large-scale applications. In this study, pilot and industrial scale tests were conducted to recycle low calorific value coal fly ash and boiler slag for the preparation of high valuable inorganic artificial stone, the activity of fly ash and boiler slag was activated by physical resonance without chemical activation. From the pilot test, it was determined that artificial stones enhanced by resonant activation behaved the higher compression strength of 75.35 MPa with 80 wt% fly ash and boiler slag utilization, which was about 45.18% increase in compression strength compared with that of conventional static agitation. The resonant activation agitation promoted the hydration reaction between fly ash and cement, generating more fibrous dense C-S-H gels. Afterword, 40 tons of raw materials were used to produce artificial stones, whose compression strength reached as high as 100.42 MPa. The whole production process was simple and pollution free, with solid waste utilization up to 80 wt%, creating a value of 160–170 US $/t. Hence, low calorific value coal fly ash and boiler slag have been realized in scale, high value and green application.

A new quantitative criterion to determine slag corrosion resistance of refractories for incinerators

Selecting the most suitable refractory lining from various types/grades of products provided by different suppliers for the hazardous waste incineration rotary kiln is not an easy job to reach a 23-month lifetime. Real-life industrial scale test is time-consuming, i.e., only one or two new products can be tested each year or every other year. Crucible test is a fast way to give a first assessment to test the adaptability of a given product to a slag. However, the classic visual observation to determine the slag penetration zone is usually inconclusive when the materials of the same group are tested and can be sometimes misleading. In this study, crucible tests were performed for 10 commercial chromia-corundum bricks from various sources. After examined with detailed analysis with SEM (Scanning Electron Microscopy) and EDS (Energy Dispersive X-Ray Spectroscopy), highly precise quantitative values of corrosion zones width for samples are derived. A non-dimensional number, the Wear ratio, is introduced as a quantitative criterion to characterize the refractory corrosion resistance. By using this Wear ratio, a correlation is found with the chromia concentration. Quantitative results obtained by this criterion are in line with the real-life observations of industrial scale tests.

Innovative application of sodium tripolyphosphate for the flotation separation of scheelite from calcite

The potential of sodium tripolyphosphate as a depressant for selective flotation separation of scheelite from calcite is investigated by the micro-flotation tests and industrial scale tests in this study. The depression mechanism of sodium tripolyphosphate is also studied by adsorption measurement, Zeta potential measurement and FTIR spectra. As suggested from the flotation test results, sodium tripolyphosphate have a good selective depression effect on calcite. The results of adsorption test, Zeta potential measurement, and FTIR spectra indicate that the selective adsorption of sodium tripolyphosphate on calcite surface hindered the further adsorption of FX-6 type sodium oleate (FX-6) on calcite surface, which prevented the flotation of calcite. However, the pretreatment of sodium tripolyphosphate have little effect on the subsequent adsorption of FX-6 on the scheelite surface, and scheelite still maintain good floatability. The selective adsorption of sodium tripolyphosphate occur between phosphate and Ca2+ exposed on the calcite surface. Sodium tripolyphosphate have the potential to be used as an alternative calcite depressant to the flotation separation of scheelite and calcite.

Efficient flotation recovery of lead and zinc from refractory lead-zinc ores under low alkaline conditions

In this study, a new flotation approach, a low-alkaline and non-desliming process, was introduced for improving lead and zinc recoveries, lowering production cost and reducing environmental pollution. Lab-scale experiments results show that the new process contributed to the flotation of the complex mixed sulfide-oxide lead and zinc ore regarding two aspects: (1) High alkaline process (pH = 12±) was replaced by low alkaline process (pH = 9±) by using collector WS (a mixture of ethyl thiocarbamate, ammonium dibutyldithiophosphate and dithiophosphate-25) and combined depressant Na2S/ZnSO4/Na2SO3 for lead sulfide flotation; (2) Non-desliming process was successfully achieved by using collector MA (a mixture of ether amine, hydroxyethyl cellulose and polyacrylic acid) and combined depressant SHP/SS (sodium hexametaphosphate/sodium silicate) for zinc oxide flotation. And 43.37% Pb in the Pb concentrate was recovered, the corresponding Pb grade was 52.73%, total 84.42% Zn was recovered by the flotation of zinc sulfide minerals and zinc oxide minerals. Moreover, the two aspects of the new approach were systematically verified from lab-scale to industrial-scale application. The industrial-scale flotation tests show that Pb recovery in Pb concentrate increased by 1.86% compared with that of original system during industrial-scale tests period, and the Pb recovery increased by 4.09% compared with that of original system before industrial-scale tests period, while the Zn operating recovery in zinc oxide concentrate improved by 19.52%. Moreover, the total reagent cost of the whole new process significantly declined by 3.93 yuan per ton of ore.

Recovery of sulfur from sulfur-rich filter cakes in a rotary kiln: Process optimization

In this work, sulfur recovery from sulfur-rich wastes deriving from sulfur filtration was investigated through laboratory experiments and full-scale tests in an industrial combustion rotary kiln, where elemental sulfur is converted to SO2 in a sulfuric acid production plant. Phase equilibria experiments carried out in the temperature range 1100–1400 °C and industrial scale tests demonstrated that temperature is the most important operating parameter in determining the recovery efficiency and the plant operability. The full-scale tests performed on the rotary kiln showed that, at operating temperatures around 1200 °C, a continuous sulfur recovery from the filter cakes was obtained with an average efficiency of 87% and a consequent reduction of about 70% of the solid waste material to be disposed as inert in landfills or used in cement/glass industries. The efficiency of sulfur recovery increases with the increasing operating temperature but, above 1300 °C, the melting of the residual Ca-Fe-Al-silicate phase and the eventual recrystallization at the kiln refractory walls occurred, causing a forced plant shutdown.The chemical-physical interaction between the sulfur-rich filter cake and different refractory materials was further investigated in the temperature range 1100–1300 °C. At the recommended operation temperatures of 1100–1200 °C, the interaction between the refractory material and the combustion ashes is negligible for all tested materials. Nonetheless, the use of Fe- and Cr-free refractory materials for the internal lining of the kiln must be preferred to minimize the deposition/adhesion of Ca-Fe-Al-silicates derived from combustion over long-term operation.

In-Suit Industrial Tests of the Highly Efficient Recovery of Waste Heat and Reutilization of the Hot Steel Slag

Waste heat recovery from hot steel slag in in-suit production lines has always been a worldwide challenge. In this paper, in-suit industrial-scale tests of the highly efficient recovery of waste he...

Experimental study on in-situ denitration using catalyst in fluidized bed reactor

This work proposed a process route for in-situ denitration in circulating fluidized bed (CFB) reactor through adding catalyst, and the feasibility has been verified through a bubbling FB reactor, a 6 kWth FB combustor and a 75 t/h CFB boiler. The effect of bed temperature, atmosphere and addition amount of catalyst on NO conversion rate were studied in the bubbling FB reactor. It was found that the increasing bed temperature, CO concentration and addition amount of catalyst can enhance the conversion efficiency of NO, and increasing concentration of SO2 and H2O have the opposite effect. The results from 20 h test suggested that a high SO2 and H2O atmosphere did not deactivate the catalyst. The continuous combustion experiments on a 6 kWth FB combustor showed that the catalyst addition not only can significant reduce NOx emission (>20%, even under conditions of low oxygen concentration and low ratio of primary air), but also does not have any adverse effect on the combustion characteristics. Similar results were also obtained from the 75 t/h CFB boiler. It was also found in the industrial scale tests that the addition of catalysts combined with the use of SNCR system would achieve better denitration effects.

Optimize flotation process of Mo–Bi sulfide ore for cleaner production

An economical and environmentally friendly beneficiation process is of great practical significance for the mining industry to achieve green and sustainable development. This study aims to optimize the traditional flotation process of Mo–Bi sulfide ore by using the difference in natural floatability of minerals for cleaner production. Single-mineral flotation tests demonstrate that the natural floatability of the sulfide minerals investigated decreased in the following order: molybdenite > bismuthinite > pyrite. Molybdenite displayed the best natural floatability in a wide pH range, and pyrite exhibited the least naturally floatable under alkaline conditions. The moderately natural floatability of bismuthinite was observed at the pH below 6, but decreased with the shift of pH to the alkaline region. Batch flotation tests indicate that the collectorless flotation of Mo–Bi sulfide ore resulted in lower flotation kinetics but higher selectivity than those of the collector flotation process. Industrial-scale tests illustrate that introducing collectorless flotation into the sequential flotation in industrial production was a feasible and reliable method of simultaneously increasing economic benefits and improving product quality. The grades of the Mo and Bi concentrates generated from the modified flotation process were 2.78% and 2.81% higher than those produced by the traditional flotation process. The daily consumption of chemical reagents in the modified flotation process decreased by more than 10%, reducing the annual cost of flotation reagent by approximately USD 60407.0. Given the characteristics of low reagents dosage, slightly environmental pollution, and high economic benefits, the modified flotation flowsheet is a promising separation process that can be extensively employed for mineral sources with similar mineralogical properties. • Natural floatability order, molybdenite > bismuthinite > pyrite. • Collectorless flotation resulted in lower flotation kinetic but higher selectivity. • Industrial application of collectorless flotation improve quality of final products. • Industrial application of collectorless flotation decreases environmental pollution.

Testes Industriais para Limpeza Química de Telas de Peneiras de Alta Frequência

A CMOC Niobras passou a adotar peneiras de alta frequência na etapa de classifiação. As telas das peneiras começaram a apresentar incrustações que reduziram a efiiência do processo. Para tentar resolver este problema, foi realizado um estudo com a utilização de reagentes químicos visando limpar e reaproveitar as telas que possuem vida útil de aproximadamente quarenta dias. O melhor reagente foi o hipoclorito de sódio, que foi capaz de remover as incrustações. Após realização dos ensaios em laboratório, foram iniciados o procedimento em escala industrial, com melhorias na efiiência de peneiramento e economia na compra de novas telas.

Pilot and industrial scale tests of high-performance permeable bricks producing from ceramic waste

Pilot and industrial scale tests for the preparation of permeable bricks were carried out in a refractory plant. The permeable bricks were firstly prepared using 82 wt% ceramic waste large aggregate by pilot test. The permeability, flexural strength and apparent porosity of the obtained permeable bricks can reach 3.2×10−2 cm/s, 6.8 MPa and 28%, respectively, and the relationships between these properties were studied. Moreover, industrial scale test was performed based on the best conditions of the pilot test, and 100 permeable bricks having a size of 140 mm × 280 mm × 80 mm were successfully produced using 600 kg of raw materials. The produced permeable brick has a high permeability of 3.0×10−2 cm/s, flexural strength of 6.3 MPa, as well as a relatively high apparent porosity of 26%, which exceed Chinese national standard GB/T 25993-2010. It has been found that a large number of through holes are homogeneously distributed within the permeable brick, which ensures the high permeability. Meanwhile, the binders make the aggregates interconnect with each other, guaranteeing sufficient mechanical strength. In addition, the energy consumption for whole producing process of permeable bricks is relatively low, about 1.4 MJ/kg. Hence, it is completely feasible to achieve industrial production of permeable bricks with good performance by using solid waste, which not only contributes to the construction of the sponge city, but also meets the requirements of cleaner production and brings obvious ecological and economic benefits.

Minimizing beneficiation wastewater through internal reuse of process water in flotation circuit

Cost-effective methods for reducing freshwater requirement and wastewater emission in beneficiation processes (particularly in flotation process) are greatly important in the modern mining industry. This study aims to minimize water consumption and wastewater generation in dressing plants by internally reusing process water at certain stages of flotation circuit . Laboratory scale tests demonstrated that locked cycle recycling of process water built up chemical reagents in water, which in turn influenced the flotation performance of valuable minerals and significantly decreased the grade and recovery of concentrates. Changing flotation reagent regimes in response to flotation fluctuations can reliably and feasibly maintain mineral recovery efficiency during the reuse process. Industrial scale tests validated that the quality of concentrates obtained with and without process water reuse did not show any considerable difference and satisfied the product specifications by carefully adjusting the dosage of flotation reagent. The required reagent dosages in the flotation circuit were reduced by more than 10% after using recycled water. Among the required reagent dosages, sodium sulfide (Na 2 S) was sharply reduced by 18.56%. Most importantly, the internal reuse of process water in the flotation circuit minimized freshwater consumption by 34.62% (i.e., from 5.2 t/d to 3.4 t/d), indicating that 525.6 tons of wastewater would no longer be generated every year. Overall, the proposed internal reuse process is a cost-effective and eco-friendly alternative for greening flotation process. • Internal reuse of process water in the flotation process is feasible and reliable. • Changing reagent suite reduces the negative effect of process water on flotation. • Internal reuse of process water minimized water consumed and wastewater emission. • Internal reuse of process water promotes the reutilization of chemical reagents.

High-Performance thermal polymerization inhibitors based on 4-tert-Butylcatechol and its compositions for petrochemical plants

tert-Butylcatechol (TBC) has been tested under laboratory conditions as an inhibitor of undesired polymerization during the processing of liquid pyrolysis products and has shown high efficiency. Pilot- and industrial-scale tests and evaluation of TBC as an inhibitor in the thermal treatment of styrene have been carried out. It has been shown that this inhibitor operates only in a composition with other co-inhibitors. An inhibitory composition of TBC and copper diethyldithiocarbamate is proposed, which has shown high performance in the thermal treatment of both pyrolysis condensates and styrene. Other TBC formulations with monohydric sterically hindered phenols have been considered.

Novel electro-dewatering system for activated sludge biosolids in bench-scale, pilot-scale and industrial-scale applications

To optimize the economics of electro-dewatering system in a new multi-layer vertical electric field for activated sludge biosolids, different-sized experiments were carried out in this study, including bench-scale, pilot-scale and industrial-scale applications. A bench-scale system was established to determine the optimal parameters of the new structure, including the mechanical pressure level, dewatering extent, processing time and sludge cake thickness. Then, a pilot-scale automated electro-dewatering system was developed to investigate the cathode fouling problems during continuous operations. A complete industrial-scale electro-dewatering system was established with 80t/d of sludge dewatering capacity based on the above work. The operational stability, the service life of the core parts and the economics were evaluated during a long time operating. Under various optimized parameters and control modes, 69% of the moisture in mechanically dewatered sludge could be reduced within 7–8min. The average energy consumption was 0.123kWh/kgdewater at 41kgdewater/(m2h) of anode processing capacity and the anode side temperature was lower than 65°C, when the anode utilization efficiency was 88.2%. The industrial-scale tests with optimized parameters demonstrated considerable economic benefits.

A New Technique for Removing Unburned Carbon from Coal Fly Ash at an Industrial Scale

Removal of unburned carbon from the high-carbon fly ash (HCFA) is essential when it is used as an admixture in cement concrete. This article deals with processing of the HCFA from the Guangdong province of China. A cyclonic-static microbubble flotation column (FCSMC), a novel device with the characteristics of internal recycling process and multiple mineralization steps, was used to separate unburned carbon from ash materials. A commercial flotation plant with a handling capacity of 110 ton coal fly ash (dry basis) per hour was set up. Using the optimum operational parameters, a clean ash with loss on ignition (LOI) of 3.08% and a removal rate of unburned carbon (RUC) of 80.41% was obtained. The calorific value of the unburned carbon products reached 3534 cal/g. Industrial-scale flotation tests on the circulation pulp pressure demonstrated that the energy input mode and internal recycling process of FCSMC separator was effective in removing unburned carbon from HCFA.

Energy Saving Study on Carbon Black Pneumatic Conveying

From the points of view of air compressor output pressure, by-pass pipe booster control modes and adjustable Laval nozzle of carbon black dense pneumatic conveying, the feasibility and quantity of energy saving of carbon black pneumatic conveying are analyzed. Several effective energy saving schemes of carbon black conveying are proposed. Then, industrial scale tests based on these schemes were carried out. By analyzing the data, energy saving of carbon black pneumatic conveying is calculated.