Waste Steam Research Articles

Convective sludge drying by rotary drum dryer using waste steam for palm oil mill effluent treatment

Abstract Achieving a more sustainable wastewater treatment plant has never been so important. Issues around energy consumption and pollutants removal efficiency are of growing importance in the context of production costs and pollution control. In the palm oil industry, more than 85% mills are managing their palm oil mill effluent (POME) via lagoons, yet the system considered less effective as the quality of the effluent hardly achieved the permissible limits. It is therefore in the best interest of the industry to employ a better practice. Convective sludge drying (CSD) has been shown to have exceptional efficiency in high-strength wastewater treatment. In this study, CSD epitomized the zero-emission of POME treatment due to the fact that; 1) It operates on low-grade steam discharged by the mill instead of electricity, leading to a huge cut on energy consumption, 2) Production of secondary micronutrients-enriched solids by-product (i.e., calcium and magnesium) that can be repurposed as fertilizer, and 3) The decoction produced can potentially be reused to irrigate the existing oil palm plantation for nutrient cycling. The treatment resulted in substantial removal of the chemical oxygen demand (COD), biological oxygen demand (BOD), suspended solids (SS), ammoniacal nitrogen (AN), and oil and grease (OG) down to 2 mg/L, 67.7 mg/L, 40.0 mg/L, 99% of BOD, COD, SS, OG, and AN removal efficiency. The operating cost was valued at USD 1.91 per m3 POME. The pilot-scale operation proved CSD is a viable alternative to the lagoons.

Exploitation alternatives of olive mill wastewater: production of value-added compounds useful for industry and agriculture

Countries producing olive oil generate a considerable amount of olive mill wastewater (OMWW), one of the most harmful agro-industrial effluents with a powerful polluting capacity. In fact, owing to its high pollution load, this effluent is extremely toxic to the whole soil-air-water ecosystem as well as to the living organisms inhabiting it (i.e., plants, animals, aquatic organisms, microorganisms, etc.). Currently, OMWW is discarded but since it includes carbohydrates, organic acids and mineral nutrients, as well as elevated contents of phenolics and other natural antioxidants compounds, it could be considered as a potential source of high value-added natural products. Therefore, the valorization of different waste streams including OMWW into fine biochemicals and the recovery of valuable metabolites via biotechnological processes is probably the main challenge faced by the olive oil industry. In light of that, the aim of the present review article is to summarize the state-of-the-art in relation to the exploitation possibilities and the use of OMWW to generate added-value compounds of great significance for the biofuel, pharmaceutical, cosmetic, chemical, food, and agriculture industries. Valorization of this significant waste steam in particular through a biorefinery platform could substantially enhance the environmental sustainability aspects of the whole industry while simultaneously contributing to the improvement of its economic viability.

Optimization Potentials for the Waste Heat Recovery of a Gas-Steam Combined Cycle Power Plant Based on Absorption Heat Pump

A new waste heat recovery system is presented to recover exhausted steam waste heat from the steam turbine by absorption heat pump (AHP) in a gas-steam combined cycle (GSCC) power plant. The system can decrease energy consumption and further improve the energy utilization. The performance evaluation criteria are calculated, and exergy analysis for key components are implemented in terms of the energy and exergy analysis theory. Besides, the change of these criteria is also revealed before and after modification. The net power output approximately increases by 21738 kW, and equivalent coal consumption decreases by 5.58 g/kWh. A 1.81% and 1.92% increase in the thermal and exergy efficiency is respectively obtained in the new integrated system as the heating load is 401095 kJ at 100% condition. Meanwhile, the appropriate extraction parameters for heating have been also analyzed in the two systems. The proposed scheme can not only save energy consumption but also reduce emission and gain great economic benefit, which is proven to be a huge potential for practical application.

Effect of hydrogen peroxide on photoelectric properties of high-transmittance FTO films prepared by spray pyrolysis

The FTO film prepared by spray pyrolysis has low efficiency and most of the precursors are discharged in the form of waste steam. According to the high oxidation property of H2O2, it is attempted to improve the film formation rate by changing the concentration of H2O2. Fluorine-doped SnO2 (FTO) thin films with high transmittance were prepared by spray pyrolysis using monobutyltin trichloride as the tin source and ammonium fluoride as the fluorine source. Different concentrations of hydrogen peroxide (0–0.08 M) are added to the precursor solution. In this paper, we studied the effect of hydrogen peroxide on the structure, surface morphology and photoelectric properties of FTO thin films. The results show that the growth rate of the FTO films increased from 6.04 nm/s to 8.36 nm/s with the increase of H2O2 concentration from 0 to 0.08 M. The optimum preparation process is H2O2 concentration controlled at 0.04 M, and FTO thin films suitable for solar cells are prepared. It has excellent performance parameters; carrier concentration:2.74 ∗ 1021 cm−3; carrier mobility:55.92 cm2 V−1 s−1; photoelectric quality factor:2.66 × 10−3·Ω−1and the average transmittance of visible light: 79.87%. At the same time, increasing H2O2 concentration leads to narrowing of optical band gap. Adding appropriate hydrogen peroxide concentration can improve the film production rate and obtain excellent quality films.

HIGH-EFFICIENT reversible solid oxide fuel cell coupled with waste steam for distributed electrical energy storage system

Recently, the penetration of renewable energy into the power sector has dramatically increased; thus, electrical energy storage (EES) systems with long duration time, high capacity, and high energy density are essential. Reversible solid oxide fuel cell (RSOFC) systems have become a promising candidate for this important role. In this study, a new RSOFC system coupled with waste steam considering the compatibility between charge and discharge modes is proposed. A lumped model of RSOFC stack was integrated into EBSILON®Professional commercial software for system analysis. Parametric studies were conducted to examine the effects of fuel composition, waste steam temperature, and steam conversion ratio on three system round-trip efficiency types: reference system round-trip efficiency (ηRT1), electrical round-trip efficiency (ηRT2), and exergy round-trip efficiency (ηRT3). Base case calculation shows that the system round-trip efficiencies ηRT1, ηRT2, and ηRT3 are 37.9%, 53.8% and 49.6%, respectively. In the parametric analysis, as hydrogen volume concentration in the hydrogen-steam mixture in the SOEC mode was increased from 10% to 60%, ηRT1 and ηRT2 increased, reaching a maximum value of 54.2% and 38.7% at 30% and 40% of H2 concentration, respectively. The exergy round-trip efficiency had the same trend as ηRT2 and reaches maximum value of 50.1%. The waste steam temperature had a small effect on all round-trip efficiency types. The increase in steam conversion ratio relatively improved ηRT1 and ηRT3, but negligibly influences ηRT2. The proposed system provided a solution for upgrading the EES system performance via integrating a RSOFC system with low exergy waste steam. The efficiencies ηRT2 and ηRT3 were much higher than ηRT1 because of the use of waste steam. The exergy round-trip efficiency with consideration of waste steam exergy was a good indicator of system performance.

Effect of burner types and steam injection methods on thermal destruction of waste refrigerants (HFC-134a)

Abstract To minimize the high auxiliary energy consumption incurred in the thermal destruction process of waste HFC-134a, fuel, oxidants, refrigerants, and steam were injected into an incinerator in different forms, resulting in the development of an optimum burner. The new designed burner with two types of steam supply methods was used for comparing waste HFC-134a destruction characteristics. Two types of burners with 100% waste HFC-134a destruction efficiency during LPG (1.0 kg/h) combustion at excess air ratio of 1.1, were employed as auxiliary fuels. The results show: 1) internal temperature of the incinerator increases regardless of burner type when steam and waste HFC-134a are supplied at the same time, 2) maximum supply of waste HFC-134a is 2.8 kg/h in a destructor without steam supply, and 3) for injection of optimum steam supply (0.5 kg/h), the maximum rates of total thermal destruction of waste HFC-134a are 3.0 kg/h and 3.4 kg/h for type-1 and type-2 burners, respectively.

Opportunities, challenges, and future perspectives of succinic acid production by Actinobacillus succinogenes.

Due to environmental issues and the depletion of fossil-based resources, ecofriendly sustainable biomass-based chemical production has been given more attention recently. Succinic acid (SA) is one of the top value added bio-based chemicals. It can be synthesized through microbial fermentation using various waste steam bioresources. Production of chemicals from waste streams has dual function as it alleviates environmental concerns; they could have caused because of their improper disposal and transform them into valuable products. To date, Actinobacillus succinogenes is termed as the best natural SA producer. However, few reviews regarding SA production by A. succinogenes were reported. Herewith, pathways and metabolic engineering strategies, biomass pretreatment and utilization, and process optimization related with SA fermentation by A. succinogenes were discussed in detail. In general, this review covered vital information including merits, achievements, progresses, challenges, and future perspectives in SA production using A. succinogenes. Therefore, it is believed that this review will provide platform to understand the potential of the strain and tackle existing hurdles so as to develop superior strain for industrial applications. It will also be used as a baseline for identification, isolation, and improvement of other SA-producing microbes.

Effect of operating variables on performance of an absorption chiller driven by heat from municipal solid waste incineration

This study presents an experimental analysis for a lithium-bromide/water waste steam driven parallel flow double effect absorption chiller evaluation. The absorption chiller analyzed is allocated at Bali refuse incineration plant for air conditioning system. This unit can supply a cooling capacity [400 USRT], [1406 kW]. A set of mathematical equations have been developed to estimate coefficient of performance (COP) of the chiller for each component. Theoretical analysis shows that increasing of the low temperature and high temperature heat exchangers effectiveness, decreasing temperature of absorber and condenser, increasing temperature of high pressure generator, and increase loading factor of the system improved the COP. The entire cycle is optimized by Engineering Equation Solver (EES) software from the standpoint of maximizing the COP via applying the direct experimental method. The optimization result of COP is obtained by the thermodynamic cycle.

Study of new cascade heating system with multi-heat sources based on exhausted steam waste heat utilization in power plant

Utilizing waste heat of exhausted steam in power plant as a new type of heat source is a key direction to achieve both energy-saving and clean district heating. This paper firstly reviews current mature waste heat utilization technologies, including “absorption heat pump”, “increasing back pressure of turbine” and “decreasing return water temperature of heat network”. Using only one method is not applicable to recovery all the exhausted steam waste heat of multiple turbine units due to its respective limitations. In view of this technical difficulty, this paper proposes a new cascade heating system with multi-heat sources based on waste heat utilization. Extraction steam and exhausted steam are involved to achieve the cascade temperature-rise of heat network water. Corresponding evaluation methods are presented, including the last-stage safety of the large unit and the comprehensive energy efficiency of the new cogeneration heating system. Taking 2 × 300 MW water-cooled units as the example to actualize the new system, the effects of key parameters on energy efficiency and economy are analyzed, and then further researches about integration optimization of the new system are developed. In this study, first keep constant return water temperature of primary heat network, the optimal condition is gained. At this point, all the waste heat of exhausted steam is recovered, the energy consumption of power plant is reduced by 33% and the total cost per heat output ct is reduced by 22.3%, compared with conventional cogeneration system. Then reduce the return water temperature in different level, both the energy consumption and the total cost per heat output ct can be further lowered, the energy efficiency and the economy are better improved.

Content and Formation Cause of VOCs in Medical Waste Non-incineration Treatment Project

When medical waste is treated by non-incineration technology, volatile organic compounds in the waste will be volatile out and form odor pollution. This paper studied VOCs productions in medical waste steam treatment project, microwave treatment project and chemical dinifection project. Sampling and analysis were carried out on the waste gas from treatment equipment and the gas in treatment workshop. The contents of nine VOCs were determined. It was found that the VOCs content in the exhaust gas at the outlet of steam treatment unit was much higher than that of microwave and chemical treatment unit, while the content of VOCs in the chemical treatment workshop was higher than that in the steam and microwave treatment workshop. The formation causes of VOCs were also analyzed and discussed in this paper.

Hydrogen bond donor solvents enabled metal and halogen-free Friedel–Crafts acylations with virtually no waste stream

We have developed a metal and halogen-free Friedel–Crafts acylation protocol with virtually no waste stream generation. We propose a hydrogen bonding donor solvent will form a hydrogen bonding network and may provide significant rate enhancement for Friedel–Crafts reactions. Trifluoroacetic acid is one of the strongest H-bond donor solvents, which is also volatile and can be easily recovered by distillation without need for reaction workup. Our protocol is a ‘green’ Friedel–Crafts acylation process: 1) the catalyst can be recovered and reused; 2) using halogen free starting material (carboxylic acids anhydride or carboxylic acids); 3) no need for aqueous reaction work-up; 4) minimum or no waste steam generation.

A collaborative detection approach for internal steam leakage of tyre vulcanization workshop with artificial immune algorithm

In manufacturing industry, internal leakage of steam trap usually results in great steam waste. In particular, internal steam leakage in tyre vulcanization workshop has significant influences on its production safety and energy efficiency. In practice, internal steam leakage problem often is ignored and it tends to be difficult to detect this leakage due to lack of comprehensive flow meter or method. This paper presents a collaborative detection method for this problem in tyre vulcanization workshop with artificial immune algorithm. In the method, internal leakage of steam trap is defined as nonself antigens, and steam pressure differentials between steam pipe and steam rooms (or bladders) are extracted as epitopes of antigens. Furthermore, periodic energy efficiency and steam pressure of vulcanizer as the danger signals are simultaneously detected. Energy efficiency is represented by damaged cells which will be identified firstly for locating the leaking steam straps through antibodies. Furthermore, the self-adaptive danger thresholds for energy efficiency are evaluated through a steam consumption model and the Levenberg–Marquardt back propagation algorithm. An immune-based clustering algorithm aiNet is then adopted to generate antibodies (detectors) for detection on the steam pressure of vulcanizer. Finally, a case study is implemented to validate this method, which shows that collaborative detection method allows locating the specific leaking steam trap and is a feasible tool to reduce steam waste and ensure the safety of steam supply.

Incineration and pyrolysis vs. steam gasification of electronic waste

Constructional complexity of items and their integration are the most distinctive features of electronic wastes. These wastes consist of mineral and polymeric materials and have high content of valuable metals that could be recovered. Elimination of polymeric components (especially epoxy resins) while leaving non-volatile mineral and metallic phases is the purpose of thermal treatment of electronic wastes. In the case of gasification, gaseous product of the process may be, after cleaning, used for energy recovery or chemical synthesis. If not melted, metals from solid products of thermal treatment of electronic waste could be recovered by hydrometallurgical processing. Three basic, high temperature ways of electronic waste processing, i.e. smelting/incineration, pyrolysis and steam gasification were shortly discussed in the paper, giving a special attention to gasification under steam, illustrated by laboratory experiments.

Full operating conditions optimization study of new co-generation heating system based on waste heat utilization of exhausted steam

Utilizing the waste heat of exhausted steam in power plant as a new type of heat source is a key direction to achieve both energy-saving and clean urban heating. In order to recycle all the exhausted steam waste heat of multiple turbine units in designing condition, the authors’ research group proposed a new cascade heating system with multi-heat source and applied it in several air cooling power plants in China. This paper focused on the system integration improving and operation strategy formulating, the main studies included: (1) Established the calculation model of system heating characteristics, and analyzed the problems about energy efficiency of system and safety of air cooled condenser in full operating conditions. (2) Introduced the “equivalent electricity of heating” as the evaluation method of comprehensive energy efficiency of the new co-generation heating system. (3) Improved the integration of heating system to further realize energy cascade utilization between turbine units. (4) Aiming at the improved heating system, the comprehensive optimization ideas of operational parameters in full operating conditions were put forward. By above methods, on one hand the “equivalent electricity of heating” of the new co-generation heating system is decreased by 16%, the comprehensive energy efficiency of system is improved, on the other the freezing risk of air cooled condenser is relieved, the operation safety of system is improved.

THE ANALYSIS OF THE INFLUENCE OF GAMMA IRRIADIATED POLYSULFONES ON THE STATIC FRICTION COEFFICIENT

The paper presents the results of studies on the effects of gamma irradiation on the static friction coefficient of thermoplastic polymer – polysulfone. These polar polymers belong to the group of amorphous thermoplastics and are widely used for various applications, e.g., automotive and electronic industries (dielectrics in capacitors), waste water recovery, medical uses (hemodialysis membranes), requiring autoclave, and steam sterilization. Polysufones are known for their toughness and stability at high temperatures. The aim of this study is to analysed changes in the static coefficient of friction in association with a contact pressure (in the range 0.2 – 0.8 MPa) depending on the ionizing radiation dose of PSU (in the range 50-150 kGy). Additionally, microhardness, and wear intensity were measured, because tribological properties of polymers as well as mechanical properties that influence their durability and applications. The studies confirmed that the static coefficient of friction increases with an increase in contact pressure (in the test range). The research has shown that mechanical (microhardness) and tribological (static coefficient of friction and tribological wear) improve as the radiation dose of irradiated material increase. Moreover, the tribological wear increases with increasing the sliding velocity. This gamma irradiated polymer is characterized by higher microhardness, a static coefficient of friction, and a higher wear rate compared to PSU in the initial state, because of changes in structure. It requires further research.

A novel mechanism for exhaust steam waste heat recovery in combined heat and power unit

Combined heat and power (CHP) has been identified as an important approach for fossil fuel utilization with high efficiency and pollutant concentration control. In this study, an optimized process for in-depth exhaust steam utilization was proposed to further exploit the energy saving potential of CHP unit. In the novel system, the utilization of the exhaust steam was combined with the heating process for air and condensate water, largely recovering the waste heat and leading to an improvement in the performance of the CHP unit. EBSILON Professional was used to build the model; and compared with the reference system, thermodynamic analysis and techno-economic evaluation were conducted to reveal the characteristics of the novel system. The results showed that, in the design condition, the exhaust steam utilization ratio in the novel system had a significant increment of 22.74% than that in the reference system, leading to a sharp increase of 16.26% in heating capacity and 0.83MW in net electricity output, bringing about 5.06% improvement in net generating efficiency. Meanwhile, the net annual revenues of the novel system can reach 1.80 million USD.

Structural Analysis of the Selected Products From the Suspension Furnace Produced in the Internal Recycling

AbstractThere are presents the internal recycling in anode furnace, in addition to mainly blister copper and converter copper. During the process there arise the two types of semi-finished products intended for further pyro metallurgical processing: anode copper and anode slag. The stream of liquid blister copper enters into the anode furnace treatment, in which the losses are recovered, e.g. copper, resulting from oxidation and reduction of sulfides, oxides and the oxidation of metallic compounds of lead, zinc and iron. In the liquid phase there are still gaseous states, which gives the inverse relationship relating to the solid phase, wherein the gases found an outlet in waste gas or steam. The results of chemical analysis apparently differ from each other, because crystallite placement, the matrix structure and the presence of other phases and earth elements are not compared, which can be regained in the process of electrorefining. One should not interpret negatively smaller proportion of copper in the alloy, since during the later part of the production more elements can be obtained, for example from sludge, such as platinum group metals and lanthanides. According to the research the quality of blister copper, to a large extent, present in the alloy phase to many other elements, which can be recovered.

Energy analysis of a lignite predrying power generation system with an efficient waste heat recovery system

ABSTRACTLignite has been extensively used for electricity generation in many regions worldwide. However, its high water content has obviously negative effect on plant thermal efficiency. Performance of lignite-fired power plant can be improved by predrying the lignite before combustion. In addition, recovery of waste heat from the dryer and the power generation system will enhance the plant thermal efficiency further. In the present study, a new lignite predrying power generation system integrated with an efficient waste heat recovery system was proposed. Both dryer exhaust waste heat and steam turbine exhaust latent heat were recovered to heat boiler feed water. Energy analysis indicates that system performance is improved significantly. The plant thermal efficiency increases linearly with drying degree and then increases at a lower rate. The generation of unused dryer exhaust changes the variation tendency of system performance with drying degree.

Biological removal effect for odor in medical waste steam treatment process

Malodorous gas will be produced in medical waste steam treatment process, which mainly consist of volatile organic compounds. Biological deodorization is a low cost deodorization technology. In this paper, biological deodorization technology in an actual medical waste disposal project was studied, and its removal efficiencies of VOCs were analyzed. The contents of four volatile organic compounds in exhaust gas were determined by gas chromatography and methylene blue spectrophotometry. The average concentration of them were: methyl-sulfhydryl 0.037mg/m3, dimethyl sulfide 0.046mg/m3, methyl disulfide 0.904mg/m3 and hydrogen sulfide 0.204mg/m3. After they were treated by biological deodorization, the average removal rates of the four compounds were methyl-sulfhydryl 93%, dimethyl sulfide 92.6%, methyl disulfide 97.6% and hydrogen sulphide 92.6%.The results showed that the four kinds of VOCs had good deodorization effect, and the national standards for emissions requirements can be met well.

6-3.余剰蒸気からのエネルギ回収量を増加させるための蒸気過熱器の開発((1)省エネルギー型機器,Session 6 省エネルギー)

6-3.余剰蒸気からのエネルギ回収量を増加させるための蒸気過熱器の開発((1)省エネルギー型機器,Session 6 省エネルギー)