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DTDC的设计和操作关系到工厂管理的安全、环保和能源消耗，在保证豆粕质量的前提下，降低DT的蒸汽消耗和降低豆粕的残溶是关键。论述了DTDC的预脱溶层、脱溶层、干燥层和冷却层的结构及关键操作参数设置，改进的DT功能性结构部件，DT的关键控制点、控制点及关键安全装置控制参数，另外论述了降低豆粕残溶及节能的措施。生产实践中，适度增加预脱溶盘数量，控制气相温度在68~70 ℃,保持脱溶层总料层高度不小于3.4 m,改进脱溶层逆流盘透气孔、搅拌叶、料位和落料控制机构和直接蒸汽喷孔，控制层料之间的压力降，延长蒸脱时间至45~55 min,经脱溶后，美国大豆豆粕和巴西大豆豆粕的残溶分别在50~80 mg/kg、 100~150 mg/kg，溶耗分别在0.3 kg/t和0.5 kg/t，KOH蛋白质溶解度分别在84%和80%~82%，尿素酶活性等指标合格，压榨厂蒸汽消耗控制在170~190 kg/t。The design and operation of DTDC is related to the safety, environmental protection and energy consumption of plant management, and it is critical to reduce the steam consumption of DT and reduce the residual solvent of soybean meal under the premise of ensuring the quality of soybean meal.The structure and key operating parameters of pre-desolventization layer, desolventization layer, drying layer and cooling layer of DTDC, improved DT functional structural components, DT key control points, control points and key safety device control parameters were discussed. Measures for reducing the residual solvent of soybean meal and energy consumption were introduced. In production practice, moderately increasing the number of pre-stripping discs, controlling the gas-phase temperature at 68-70 ℃, keeping the total material layer height of the desolventization layer not lower than 3.4 m, improving the desolventization layer countercurrent disc ventilation holes, stirring blades, level of material and material control mechanism and direct steam injection holes, controlling the pressure drop between the layers of material, prolonging the steaming time to 45-55 min. After desolventization, in US soybean meal and Brazilian soybean meal, the residual solvent were 50-80 mg/kg and 100-150 mg/kg, solvent consumption were 0.3 kg/t and 0.5 kg/t, KOH protein solubility were 84% and 80%-82%, respectively, urease activity and other indicators of soybean meal were qualified, and steam consumption in the pressing plant was controllled in 170-190 kg/t.

While conducting the energy audit, a systematic approach is required. In this approach steps like preliminary survey, preparatory work, main audit/assessment, on-site and machine measurements, data collection, data validation, energy-saving calculations and report preparation are the requirements. To do this an auditor must have a knowledge of textile engineering as well as processing. The past data analysis, energy balance, in-depth equipment inspection and heat utilization factor estimations are the key areas to be seen during the energy audit. [ABSTRACT FROM AUTHOR]

Integrated ethylene oxide/ethylene glycols (EO/EG) plants are prominent energy consumers in the petrochemical sector, particularly concerning high‐pressure steam (HPS) usage which holds the potential for substantial energy savings. This study focuses on an unexplored territory: Examining the impact of EO catalyst type, selectivity, and glycols production capacity on HPS import in a plant in the Pars Special Economic Energy Zone (PSEEZ). Utilizing Python3 for data preprocessing and ordinary least squares linear regression analysis, we evaluate how varying catalyst loads and production scenarios influence HPS import. Regression models are created, encompassing normal and efficient HPS import scenarios, yielding positive outcomes in terms of correlation, mean error percentage, and R2 analysis. Comparing normal and efficient HPS import models highlights potential savings, uncovering opportunities to conserve between 45 and over 200 tonnes per day of HPS. We also explore the plant's HPS behaviour under 1% selectivity and production capacity reductions. Notably, catalyst activity decline markedly escalates HPS import for hybrid catalysts, while selectivity decline decreases HPS import for high‐activity catalysts. The models demonstrate that HPS import is ~150 tonnes per day more sensitive to a 1% change in selectivity compared to production capacity. Moreover, when comparing high activity and hybrid catalyst scenarios in normal and efficient cases, the most substantial HPS import difference arises under conditions of low selectivity, amounting to nearly 200 tonnes per day. Our methodology applies to other EO/EG plants. It is incorporated into our plant's energy management system, enabling continuous monitoring of steam import behaviour relative to catalyst and plant performance. [ABSTRACT FROM AUTHOR]

The LAUNCH MELT™ Ultra-Low Energy urea plant concept, which was launched during the Stamicarbon symposium in 2012 as a 5XX design, was designed, constructed and successfully put into operation for three grassroot plants in China since the beginning of 2021. All three plants were designed with same name plate capacity of 2334 MTPD urea prills. To date, three more Ultra-Low Energy grass-root plants; two plants under construction are expected to be in operation in the middle of 2024 and a further plant is in the engineering phase. Based on actual plant operation, the Ultra-Low Energy Design for a melt plant with prilled product demonstrates a steam consumption (23 bara, 330°C) of less than 567 kg steam/ton product compared to traditional LAUNCH MELT™ Pool Reactor Designs (former Urea 2000plus®) with slightly below 870 kg steam/ton product. This paper highlights the process design aspects as well as operational experience of grass root Ultra-Low Energy urea plants in operation in China, along with a comparison of the key performance parameters, including steam consumption and product quality. [ABSTRACT FROM AUTHOR]

Objective The purpose is to reduce energy consumption of the sulfur recovery unit through technological transformation and optimization of operating parameters. Methods (1) By analyzing the current energy consumption status of the unit, the technical transformation is adopted to solve the typical problems in energy saving and consumption reduction; (2) The quality of purified water is improved by optimizing stripping operation parameters. Results The technical transformation has obtained the following results: (1) Reducing the consumption of 1.2 MPa steam and 0.4 MPa steam in the device; (2) Effectively improving the comprehensive utilization rate of purified water, and reducing the consumption of production water and desalinated water as well as sewage discharge throughout the plant. Conclusions After technological transformation, the comprehensive energy consumption of the unit has decreased from the original 1 000 kgEO/t to the current 660 kgEO/t, and the reuse rate of purified water has increased from the original 40.0% to the current 83.5%. [ABSTRACT FROM AUTHOR]

Modeling of the dryer section of a paper machine is of high importance in both designing and operation points of view. In this research, a novel thermodynamic and heat and mass transfer model has been introduced. The model is based on empirical equations of the literature and does not need fine discretization techniques such as finite difference method. The method used for calculation of convective heat and mass transfer coefficients of the dryer is a modification of the methods utilized in the literature. The trend of paper and air temperature in the dryer, the steam consumption of each cylinder, as well as the trend of drying process throughout the dryer has been calculated. Overall results of the dryer such as the total evaporated water and the specific steam consumption of the dryer have been obtained too. The results have been validated with experimental data of a previous research in the literature and show a relatively good agreement with the experimental data. Finally, the sensitivity of the results to some main parameters has been analyzed. [ABSTRACT FROM AUTHOR]

The results of a numerical study of the gas-dynamic and power characteristics of the exhaust compartment of low-pressure cylinder, including the last stage with a blade of 1100 mm length and the exhaust path, in terms of their interaction are presented. Numerical models of exhaust compartment variants, including steam extraction in front of last stage diaphragm, two steam suctions from the interring gap with a dehumidification chamber, above-band leakages, steam injection from the dehumidification chamber into the diffuser channel have been developed. The flow in each computational subdomain is described by the complete system of non-stationary Reynolds – Favre equations averaged by Navier – Stokes. Turbulent effects are described with the SST Menter model in the stage, and with the modified Spalart – Allmaras turbulence model in the path. The integration of system of equations was carried out using an author’s software package. The calculated subdomains were approximated by hexagonal grids. The solver used an implicit difference TVD-scheme of finite volumes of the 2nd order of accuracy based on the solution of the Riemann problem. A variant of the algorithm based on splitting the computational process for multiprocessor platforms was used in the calculation. The model of stage used an averaging the mass, momentum and energy fluxes in the circumferential direction in the interstage gap. One channel of the diaphragm with a pre-connected fragment, as well as one channel of the working ring and the flow in the branch pipe were calculated. Parameters were exchanged between the stage and the branch pipe on the basis of mass flow averaging. The calculations were based on a table model of wet steam in the approximation of equilibrium condensation. The variants of improvement of the flow part of the exhaust compartment were considered. A study of the operation of the compartment options for the nominal mode of the K-220-44-2M turbine of the Loviisa nuclear power plant was performed. The effectiveness of lowering the cap of the collecting chamber, controlling the flow using sheet ribs above the diffuser shell, expanding the collecting chamber in the plane of the horizontal connector, and ensuring the release of excess steam from the moisture removal chamber through the tangential slots in the lower half of the convex shell of the diffuser were analyzed.

Relevance. Redeveloping of the existing heat-power equipments is one of the priority areas of power generation development. Adoption of gas turbine unit to the thermal scheme of steam-power energy unit with the preservation of power plant infrastructure is a less costly variant comparing with the construction of new combined cycle power plants energy units. One of the low-cost variant for the integration of gas turbine units into the thermal scheme of steam-turbine energy units is to use the heat recovery steam generator thermal capacity for reheating the working fluid spent in the steam turbine with utilization of the remaining heat for feed water and main condensate heating. Compared with the most common schemes with displacement of regenerative heating to heat recovery steam generator, the proposed alternative variant allows increasing the thermal efficiency of the steam-turbine circuit. The analysis of gas turbine units energy characteristics showed the need to research the scheme and parameters of the steam reheating for heat-extraction energy units taking into account the operating modes of steam turbine. Object: steam-turbine energy unit T–165/210–130 with gas turbine topping (GT-topping) for reheating of the working fluid spent in the steam turbine with utilization of the remaining heat for feed water and main condensate heating. The aim of the research is to select scheme and calculate the optimal parameters of steam reheating as applied to the steam-turbine energy unit T–165/210–130 with GT-topping, analyze its main performances during the work on the heat schedule when steam reheating temperature changes in heat recovery steam generator. Methods: system analysis and mathematical modeling. Results. The authors have developed the mathematical model and program for calculating the proposed scheme and performed the features analysis associated with the organization of steam reheating in GT-topping heat recovery steam generator. Furthermore, we showed that the efficiency of heat-extraction energy unit with steam reheating can be increased by organizing steam reheating in GT-topping heat recovery steam generator. In addition, we determined that in this case, the highest efficiency of a steam-turbine energy unit with GT-topping during operation in the design heat-extraction mode is achieved, when steam reheating temperature is below the nominal value.

Based on the operation data of the hydrocracking unit, the simulation process of hydrogen sulfide removal stripper is constructed by Aspen Plus software, and ELECNRTL is used to simulate and optimize - 26 - the process of hydrogen sulfide removal of oil from low pressure separator. The effects of key parameters, such as stripping steam consumption, feed temperature and feed position of oil from cold low pressure separator, feed position of oil from hot low pressure separator, on hydrogen sulfide removal efficiency and energy consumption of stripper are investigated. The results show that under the existing operating conditions, the stripping steam is excessive, and the energy consumption is unreasonable. With the adjustment of feed position of oil from hot low pressure separator, the stripping steam consumption reduces from 3. 5 t/h to 1. 5 t/h. Combined with the comprehensive analysis of the heat exchange network of the unit, following the principles of high heat high utilization and energy cascading utilization, the improvement and optimization measures for the preheating process of oil from cold low pressure separator are put forward. Through the rational use of high temperature potential heat, the overall energy efficiency of the unit is effectively improved. [ABSTRACT FROM AUTHOR]

In this work, a study was carried out in UEB Sugar Factory "Urbano Noris" in the province of Holguín to evaluate the current behavior of the main energy parameters in the cogeneration process. Firstly, the steam generation system was analyzed and the generation efficiency and the different lines of energy losses were determined with the causes that origin them. Subsequently, the study of the production process was carried out, making the mass and energy balances in all sections of the same to determine the different flows and the consumption of water vapor needed in all the primary and technological equipment of the system. Next, the essential balance of bagasse was carried out to determine the relationship between the consumption and availability of this fuel and the different energy efficiency indices were calculated, where the results obtained correspond to a 65,15% efficiency of generation being satisfactory, the generation rate turned out to be 2,42; the consumption rate in Casa de Calderas was 0,47 kg of steam / kg of cane, the highest percentage of energy loss was due to the high humidity of the bagasse, the remaining bagasse represents 16,84% of the bagasse available in the industry and the percentaje of steam used in the evaporation system produced by itself was 35,32%. [ABSTRACT FROM AUTHOR]

The use of renewable sources has been an alternative to decrease the negative environmental impacts of fossil fuels. In this context, bioethanol from sugarcane has proved to be a successful option to gasoline. However, bioethanol purification through conventional distillation requires high-energy demand. For this reason, energy balance calculations are very useful to estimate steam demand. As a result, simpler alternatives for estimation of steam consumption from spreadsheet calculations have been encouraged. In contrast, many efforts have focused to solve complex flowsheets including tear streams, which increases convergence complexity for each change on feed composition and additional components. In this work, mathematical models were fitted to bioethanol–water mixture property data and applied to energy balance calculations involved in the conventional process for hydrated bioethanol purification. Total steam consumption was obtained for volume percentages of bioethanol in the wine feed stream of 6, 8 and 10 °GL considering potential losses found in the industrial reality. The calculated data were compared to simulations carried out in the Aspen Plus® software. Similar values of total steam consumption were found comparing the two approaches, where the average absolute relative deviation was kept below 5%. Moreover, simulated temperature and composition profiles agreed to process data. Finally, mathematical models and energy balance calculations proved to be a simpler and faster alternative to estimate total steam consumption involved in the hydrated bioethanol purification from wine. [ABSTRACT FROM AUTHOR]

In order to solve the problem that the gasoline pool olefins of Petro China Lanzhou Petrochemical Company can' t meet the national VI ( B) standard of ethanol gasoline blending component oil, the MIP process technology reformation was carried out on the 3 X 106 t / a heavy oil catalytic cracking unit. The MIP process technology was a new type of reaction system in the form of a series riser reactor developed by the Sinopec Research Institute of Petroleum Processing. The second reaction zone was connected in series through the riser to enhance hydrogen transfer and isomerization reactions, thus achieving the purpose of reducing gasoline olefin content and increasing the gasoline octane number. The device has been running smoothly since it was first started in .June 2019. By comparing and analyzing the main economic and technical indexes such as olefin content in gasoline, RON, steam consumption, economic performance, etc. before and after technological transformation, the olefin volume fraction in gasoline reached the design requirements, which was 7. 2% lower than before the transformation, the RON increased by l unit, and the steam consumption of the reaction regeneration system reduced by 8. 3 t/h. The device operation optimization and economic improvement also had good effects. [ABSTRACT FROM AUTHOR]

Abstract—It is established that optimizing extremal control of benzene distillation is expedient so as to maximize its extraction from absorbing oil. An effective method is described for finding the maximum possible benzene extraction, with appropriate regulation of the steam supply to the distillation column so as to permit dynamic temperature control. Simulation of the search process verifies the applicability of such control in digital systems. This approach does not impose excessive implementation costs, maximizes benzene extraction, and significantly limits the staff's role in the control of distillation. [ABSTRACT FROM AUTHOR]

Abstract Increasing energy demand, high energy cost and global warming issues require energy-intensive industries to make sincere efforts to improve energy efficiency. The energy consumption data available for different industries suggests that pulp and paper industry accounts for a significant share. Amongst various procedures to make paper, Kraft recovery process is majorly employed that yields weak but lignin-rich black liquor as a byproduct. Black liquor is one of the emerging biomass energy resources with a strong potential to be used as a biofuel for generating steam/energy to operate the process units, thereby, ensuring process self-sufficiency and sustainability. A Multi-Stage Evaporator (MSE) is needed to concentrate it but suffers from being the most energy consuming unit among all. This piques our interest to explore various energy reducing schemes or configurations used previously for MSE and to report previous research endeavors in the area of steady–state, dynamic modeling and simulation of such processes. It is noted that steady-state and transient behavior analysis together with an efficient controller design may significantly contribute in eliminating or troubleshooting problems to ensure both energy savings and product quality. The article highlights that such an analysis and effective solutions of developed models, due to their non-linear complex nature, are highly dependent on the nature of the algorithm employed. Attempts to design control techniques to enable efficient process control and to eliminate process uncertainties have suffered limitations not only due to inherent inefficiency of control techniques but also due to insufficient underlying knowledge or inappropriate modeling of system transience. With this perspective in mind, advanced and intelligent control techniques and their influence on process/energy transience and optimization have been reviewed. Here, we propose that it is very essential to maintain sufficient prudence in selecting an appropriate simulation, optimization and control algorithm to ensure a sustainable production. Highlights • Status of performance of energy intensive industries present worldwide in the light of current global energy scenario. • Significance and challenges of multi-stage evaporation (MSE) in paper industry. • Review of energy efficient configurations of MSE and their optimization to achieve higher energy efficiency. • Developments in the area of linear and nonlinear steady-state and transient models and control of MSE. • Challenges and limitations of available numerical techniques in solving complex nonlinear problems of such systems. [ABSTRACT FROM AUTHOR]

Highlights • Highly complex set of simultaneous nonlinear algebraic steady state equations model for multiple stage evaporator has been developed. • Proposed different energy reduction schemes. • Genetic Algorithm has been proposed to solve these developed set of simultaneous nonlinear algebraic equations to optimize the cost function energy efficiency. • Compare the obtained optimized energy efficiency with other previous published models to improve the black liquor product quality. Abstract Maximization of the steam efficiency of a multiple stage evaporator employed for concentrating black liquor in pulp and paper mills carries immense significance and relevance in today's scenario. Nonlinear mathematical models of heptads' effects backward feed flow with various energy saving schemes namely, steam-split, feed‐split, feed-preheating and their hybrid operations have been developed. The steam economy as a cost function translates the problem into a nonlinear optimal search problem. The mass and heat balance equations act as nonlinear equality constraints while vapor temperatures and liquor flows appear as inequality constraints. The formulated problem has been solved efficiently to attain optimal solution using Genetic Algorithm approach which demonstrates advantages of convergence and relative less sensitivity towards initial values versus conventional algorithms. The simulations indicate that a hybrid of steam-split, feed-split and feed-preheating process arrangements with backward feed flow could provide the highest heat transfer across evaporator effects with an optimum steam economy of 6.47 and consumption of 6541.93 kg/h. [ABSTRACT FROM AUTHOR]

The maximization of the energy (steam) efficiency of a multi-stage evaporator system used for concentrating the black liquor in pulp and paper mills carries immense significance in today's scenario. The nonlinear mathematical models of heptads' effect backward feed flow with various energy saving schemes namely, steam-split, feed-split, feed-preheating and their hybrid operations have been developed. The steam economy as a cost function translates the problem into a nonlinear optimal search problem. The mass and heat balance equations act as nonlinear equality constraints while vapor temperatures and liquor flows appear as inequality constraints. The formulated optimal problem has been solved efficiently using Interior-Point Method which demonstrates advantages of convergence and less sensitivity towards initial values versus conventional algorithms. The simulation results indicate that a hybrid of steam-split, feed-split and feed-preheating process arrangements with backward feed flow could provide the highest heat transfer across evaporator effects with optimum of steam economy of ∼6.49 and consumption of ∼1.97 kg/s. [ABSTRACT FROM AUTHOR]

As a by-product of oil refining and petrochemical production process. C4 hydrocarbon productions increase year by year. It is estimated that the total annual C4 hydrocarbon productions of refineries in China are more than 6 million tons, therefore the research of C4 component separation and utilization of deep processing has important strategic significance and practical effect on the development of China's ethylene industry and related industries. At present, there are some difficulties on the extractive distillation of C, hydrocarbon separation and deep processing such as tray pressure drop larger, processing capacity not up to the full load, separation index of unqualified, high energy consumption. In this paper, the problems of C4 hydrocarbon extraction towers and stripping towers before the renovation in Ningbo Haode Chemical Corporation are introduced. In view of the existing problems, the original DJ valve trays are replaced by the complete countercurrent trays. After the reconstruction, the processing capacity increases from about 80% loading to 130% loading* the steam consumption is saved by 35%. all indicators of productions are better, the phenomenon of liquid blocking device don't appear, and all devices are running smoothly. [ABSTRACT FROM AUTHOR]

Non-linear programming optimization method was used to optimize total steam and air consumption in the dryer section of multi-cylinder fluting paper machine. Equality constraints of the optimization model were obtained from specified process blocks considering mass and energy balance relationships in drying and heat recovery sections. Inequality constraints correspond to process parameters such as production capacity, operating conditions, and other limitations. Using the simulation, the process parameters can be optimized to improve the energy efficiency and heat recovery performance. For a corrugating machine, optimized parameters show the total steam use can be reduced by about 11% due to improvement of the heat recovery performance and optimization of the operating conditions such as inlet web dryness, evaporation rate, and exhaust air humidity, accordingly total steam consumption can be decreased from about 1.71 to 1.53 tonnes steam per tonne paper production. The humidity of the exhaust air should be kept as high as possible to optimize the energy performance and avoid condensation in the pocket dryers and hood exhaust air. So the simulation shows the supply air should be increased by about 10% to achieve optimal humidity level which was determined about 0.152 kgH2O/(kg dry air). [ABSTRACT FROM AUTHOR]

This paper presents the genetic algorithm approach to solve the highly complex set of fourteen simultaneous nonlinear algebraic benchmark problem for the backward feed seven effect evaporator. Generally, Newton's method may be considered a better numerical technique to solve such nonlinear problems. However, a higher number of effects (seven in this case) complicates the evaluation of a 14 × 14 Jacobian matrix that involves determining the analytical derivative of all system variables. Also, such a simultaneous nonlinear algebraic equations model exhibits the problem of divergence and instability when initial values have not been chosen appropriately. In this work, genetic algorithm approach has been demonstrated to be very efficient to solve such complex nonlinear models for a large number of effects in evaporative system without any complications. To make the model more realistic and representative of physico-thermal properties of liquor, boiling point elevation of the liquor during evaporation has been incorporated. Finally, the developed models are solved using genetic algorithm to determine the process variables, namely liquor and steam flow rates, which yield process performance parameters of energy efficiency (steam economy and consumption). The results indicate that a maximum steam efficiency may be achieved for a 50 % steam split in the first two effects. [ABSTRACT FROM AUTHOR]

A general and rigorous mathematical model is developed for a multiple effect evaporator system which includes various energy reduction schemes (ERSs). These ERSs are thermal vapor compression, vapor bleeding, condensate flashing and solution flashing. The model can achieve the function of pumping steam at any effect and can work as an effective screening tool for the selection of optimal feed flow sequence (OFFS). In order to solve the model, the iteration method combining with matrix methods is proposed. To study effect of different ERSs on steam consumption (SC), an example of the co-current quadruple effect evaporator system is considered. These schemes can reduce the SC up to 46.56% if the feed is heated up to 88 °C and ejection coefficient at 3rd effect is set to 0.3. The OFFS is forward sequence as long as preheating temperature is high enough when constraints of heat transfer driving force can be satisfied. [ABSTRACT FROM AUTHOR]

This paper describes such quantitative characteristics and operational parameters for marine turbogenerator as: efficiency, and steam consumption per unit or hour for various loads. Characteristic numbers and operational parameters were estimated from the results of operational tests of a turbogenerator aboard a petroleum tanker. [ABSTRACT FROM AUTHOR]

Over the past few decades, the development of the energy market was marked by market liberalization, a surging appetite for energy in the developing world, constantly high energy prices, energy security concerns, a growing awareness of climate change, and introduction of the emissions trading. These issues result in the growing importance of energy efficiency for the chemical and life science industries. This article describes a systematic approach to achieve higher energy efficiency in the Swiss chemical and life science company Lonza Ltd. A particular energy-saving project focusing on the optimization of infrastructure is presented.

ABSTRACT Using different kinds of amines, in Fajr-e-Jam gas refinery, including mixed or activated amines, have provided the chance for better analysis of different kinds of amines performance. In the current work, the most important parameters in gas sweetening refineries such as amine circulation rate, steam consumption, CO2 and mercaptan removal were investigated for sweetening trains utilizing diethanolamine (DEA), methyldiethanolamine (MDEA), DEA/MDEA and activated methyldiethanolamine (aMDEA). In the case of steam consumption and circulation rates, MDEA and aMDEA, show the less required rates to meet lean amine loadings. For CO2 removal aMDEA has the best efficiency. In the case of mercaptan removal, DEA shows the best absorption rate compared with other three amines. © 2014 Curtin University of Technology and John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Highlights: [•] Steam consumption for water venting vs. conventional venting were determined. [•] Water venting saves up to 50% steam with reference to conventional process. [•] Water venting higher temperatures yield lower steam consumption. [ABSTRACT FROM AUTHOR]

Abstract: The operation named venting is a step in the sterilization process in retorts using steam pressure. It is intended to remove all air from the inside of the equipment by injecting steam. Although only for a short period of time, great quantities of steam are used, making venting an expensive operation. This study aimed to evaluate an alternative to the venting process with a reduction in steam energy expenditure. A system was adapted and instrumented, which allowed for the study of the phenomenon of venting using water for the air displacement. The alternative methodology proposed was shown to be promising and efficient for an empty retort with no load. The efficiency at this stage of the study was based on evaluating the differences in the temperature readings using a glass mercury thermometer and the temperatures recorded by thermocouples distributed within the retort. [Copyright &y& Elsevier]

Abstract: Steam recovery and consumption contributes greatly to energy consumption per ton of steel. It is studied in this paper that the relationship between energy consumption per ton of steel and steam recovery & consumption, including main processes, auxiliary processes, diffusion and other users, respectively. And the factors attributing to energy consumption per ton of steel is analyzed. The expressions of steam consumption per ton of steel and energy consumption per steam supply are proposed in this paper. [Copyright &y& Elsevier]

Abstract: The energy efficiency of multi-stage steam-jet-ejector vacuum systems was improved by solving the following main tasks: (i) systems analysis of these multi-stage plants and (ii) a selection of eligible surface roughness of steam-jet- ejectors as a way for reducing their hydraulic losses and steam consumption. The systems analyse reveals that the consumption of motive steam and cooling water can be reduced when (i) the last stage of vacuum systems employs a water-ring vacuum pump instead of steam ejectors; (ii) four-stage vacuum systems are applied when cooling water with temperature above 30° is used; (iii) the first stage of vacuum system is without a condenser when the plant uses cooling water with temperature above 30°C; (iv) the values of intermediate pressures in the end of the first and the second stages are optimized by means of a minimization of the total consumption of motive steam and cooling water in these stages. An engineering approach was developed for determining the eligible surface roughness of ejectors depending on Re number and the diameter of actual section. This approach assures to be obtained a minimal linear friction factor in each section. On this basis the eligible values of roughness average Ra for seven representative sec- tions of ejectors were specified. A family of four-stage vacuum systems with suction flow from 10 to 75kg/h vapour- air mixture at a suction pressure 300Pa was developed and commercialized. Twelve vacuum systems have manufac- tured and introduced successfully for deodorizing vegetable oils in Bulgarian enterprises. [Copyright &y& Elsevier]

Abstract: In the present work different energy reduction schemes (ERSs), used to reduce the consumption of steam for a multiple effect evaporator (MEE) system, are developed. These ERSs are condensate-, feed- and product-flashing and vapor bleeding. Further, a new scheme is proposed where condensate of vapor chest of an effect is used to preheat the liquor, which is entering into that effect using a counter current heat exchanger. This work also presents a comparative study between existing ERSs and selects the best ERS amongst these based on steam consumption as well as number of units involved. Further, in the present paper a simple graphical approach named “modified temperature path (MTP)” is developed for the analysis of different feed flow sequences of a MEE system to screen best possible feed flow sequence. To study the effect of different ERSs on steam consumption and MTP analysis an example of septuple effect flat falling film evaporator (SEFFFE) system, employed for concentrating weak black liquor in an Indian Kraft Paper Mill, is considered. The results show that ERSs reduce the steam consumption up to 24.6%. [Copyright &y& Elsevier]

A regression analysis is made in turbo generators of the sugar industry between the specific consumption of steam and the main parameters of operation of these equipments as the initial and final pressures of the vapor, temperatures, efficiencies and powers. Equally, it is made between the total consumption of steam and the mentioned parameters. Finally, it is improved the traditional calculations for the steam consumption of these equipments. [ABSTRACT FROM AUTHOR]

Development of paper industry has been restricted by resources, energy and environment deeply; further reducing energy consumption becomes an urgent problem to be solved. In this paper, the calculating model of steam consumption in bleaching process is established under the premise of ensuring product quality and controlling bleaching cost. Then, an optimization model for minimizing steam consumption is constructed. Compared with before optimization, the steam consumption of the optimized bleaching system reduced by 19.48% (0.5014 t/adt) at a loss of 0.11% brightness (0.1 ISO%) and 5.17% viscosity (33 mL/g). The amount of chemicals should be increased to ensure the quality of the pulp while decreasing the bleaching temperature to reduce steam consumption, the cost of bleaching pulp has decreased by 1.62% (3.19 USD/adt) after optimization. The verification experiments showed all the pulp quality indices can meet the requirements of bleached pulp. [ABSTRACT FROM AUTHOR]