Artículos de revistas sobre el tema "Natural circulation boiler"

Modeling of a natural circulation boiler for a coal-fired thermal power station is presented here. The boiler system is divided into seven subcomponents, and for each section, models based on conservation of mass, momentum, and energy are formulated. The pressure drop at various sections and the heat transfer coefficients are computed using empirical correlations. Solutions are obtained by using SIMULINK. The model is validated by comparing its steady state and dynamic responses with the actual plant data. Open loop responses of the model to the step changes in the operating parameters, such as pressure, temperature, steam flow, feed water flow, are also analyzed. The present model can be used for the development and design of effective boiler control systems.

The paper describes research and design of fluidized bed steam boiler natural circulation circuit. The capacity of the drum boiler is 85 MW, superheated steam pressure is 98 bar. There are two variants research results of the designed circulation circuit. The first circulation circuit variant was designed as a complex circuit with a common downcomers and risers for the boiler evaporating screen. In the second variant the flow is separately supplied to and discharged from the evaporator that is divided into independent sections. We have researched and described the influence of heat absorption inequality on the furnace evaporation pads using the Boiler Designer software. We also have calculated main characteristics of the two-phase flow in the evaporation pads and evaluated reliability of the natural circulation. The circulation circuit is optimized from point of view of reliability and metal expenses. Results demonstrate that the specific quantity of metal of complex and simple circuit variants is approximately the same with equal reliability.

In this present works, a generalized approach for the two-phase flow analysis of a natural circulation in hybrid boiler. The model uses the combination of node and loop equations and the Newton Raphson technique for the solution of the set of equations. Loop equations have been developed for each evaporator tube with the unique driving force and pressure drop of the concerned loop. Node equations are mainly developed for common risers and downcomers. A unique connectivity matrix has been used to correlate each branch flow with loop and node equations. The model is validated by a unique indirect method by comparing the actual water level and calculated water level. Experiments have been performed with uniform diameter of tubes in 53 channels circulating loop to find the volume of steam. The model shows good agreement with experimental investigations with a maximum of 3.57% absolute error. The model can be used for the design, analysis, and optimization of the natural circulation network.

The paper shows the method of determining the start-up curves of a steam boiler, which enables its faster start-up. Faster temperature changes cause thermal stress, especially in thick-walled boiler elements. Critical elements that limit the rate of change of working fluid units include drums, outlet chamber, injection chamber, fresh steam superheater of steam coolers, tees and valve casings, rotor and turbine casing. The walls of these elements have the thickest walls due to the high pressure values occurring in them during operation. Allowable changes in temperature and pressure during start-up and shut-down can be determined by the European Standard EN 12952-3. The article shows how the start-up curves of a steam boiler can be determined using the European Standard and the method proposed by the author. Calculation results show that the starting time of the analyzed block can be significantly shortened.

The paper presents different models used to determine pressure losses in two-phase flows: the homogeneous model, the Lockhart-Martinelli, the Friedel and the Chisholm phase-slip models and the Martinelli-Nelson graphical method. The pressure losses are calculated for the evaporator of an OP-210 boiler with the output of 210×103 kg/h operating in one of the Polish power plants. The results obtained by means of the presented models are compared to each other.

This paper describes the specifics of the waste incineration boiler with natural circulation fueled with municipal waste. During operation, certain parts of the boiler are exposed to corrosion and erosion due to effect of particles from the flue gas stream at high temperature. Tests have been performed which include sediment and pipe damage after one year of boiler work. Chemical analysis of sediment samples was taken from the tubes was determined presence of NaCl and Fe compounds and share from 18 % organic substances in the presence of SO3.

Drum is the core pressure equipment of Natural Circulation Boiler. The harsh working conditions lead drum to be prone to failure in power station boiler system. This article presents a systematic analysis of factors which may cause the failure of the drum and builds the fault tree with the drum failure as the top event. Through calculating each order of minimum cut sets and importance degree of each basic event probability to determine the major influent factors for the failure of drum, this article puts forward the corresponding solutions and brings reference value to safe operation and maintenance of boiler drum.

The research work, Ascertaining the connection type between evaporating tube bundle and a steam drum shell on a Natural Circulation marine supercharged boiler, is important. For this reason the method, calculating the low-cyle fatigue life of supercharged boiler steam drums put forward by Xin-wei Zheng, et al., was put to use; Based on the relevant basic data from design department and two typical running conditions of one supercharged boiler, the cumulative fatigue damage ratio of welding technique was calculated. The calculated result proves that it exceeds the maximum value of 1.0 and the upper limit value of 0.75 in fossil-fuel power plants, respectively. So welding technique can’t guarantee the low-cycle fatigue life of this steam drum, the only connection type is expanded joint, and the connection type has been put into practice.

In this paper, a new system which absorbs the water vapor in flue gas of natural gas fired boiler (NGFB) by desiccant solution is introduced. This system can recover the latent heat of water vapor and improve the thermal efficiency of the NGFB significantly. In the theoretical analysis, the packed tower which is the most important equipment of solution circulation heat recovery system (SCHRS) can be designed by establishing a mathematical model. Based on the recovery efficiency of water vapor by desiccant solution absorption, the thermal efficiency analysis of NGFB is discussed, which show that SCHRS has a good application prospect in NGFB waste heat recovery.

A 215MW cogeneration B&W670/13.7-M type high-pressure natural circulation boilers, the exhaust gas temperature is set as 143 °C, while in the actual operation, the average exhaust gas temperature is 155 °C, and when the unit is running at full capacity in summer the highest exhaust gas temperature is 169.6 °C. In order to satisfy the normal operating temperature of bag filter in summer peak load, and recover low temperature waste heat of fule gas, low temperature economizer is added to the thermal system. Therefore, low-temperature economizers are respectively added in four flues which are between the outlet of the air preheater and the entrance of the bag filter, this will achieve the purpose of reducing flue gas temperature by transferring heat between condensate and flue gas, ensuring the units safe operating and improving the overall operating performance of the boiler.

This paper presents the results of theoretical flow stability analyses of two different types of natural circulation heat recovery steam generators (HRSG)—a two-drum steam generator—and a HRSG with a horizontal tube bank. The investigation shows the influence of the boiler geometry on the flow stability of the steam generators. For the two-drum boiler, the steady-state instability, namely, a reversed flow, is analyzed. Initial results of the investigation for the HRSG with a horizontal tube bank are also presented. In this case, the dynamic flow instability of density wave oscillations is analyzed.

The article discusses the synthesis of a control system that implements optimal control of a double-drum water-tube boiler with natural circulation with effective suppression of disturbing influences and ensuring astatism of the control channel. One of the main channels of the object is described in the most detail, the channel “fuel consumption - pressure of superheated steam”, which is decoupled from others. Therefore, it is for him that we will carry out the calculation of the automatic control system (ACS), the reaction of the system to a stepwise disturbing effect is indicated. Using the method of mathematical modeling, the operability of the synthesized control system was confirmed, its operability when the parameters of the model were varied twice, which indicates the possibility of transition from model to physical tests of the proposed control algorithm.

Control of the water level in the drum of the boiler system is a critical operation consideration, because asymmetric dynamics of water level measured leads to measuring errors. This phenomenon is testified by field data from a 400t/h drum boiler with natural circulation in a power plant of China. Some equations are developed and several related factors are focused on, and two of which become critical ones accounting for asymmetry of measured value. With the study of structure of distribution pipes in drum, it is found that feed-water flows distributed on the opposite ends of drum are obviously asymmetric, where measurement systems are positioned. When more feed-water is supplied at one end of drum, the rate of steam in water and water temperature become lower, and measured level get higher. Through the simulation, the important factors for asymmetric of water level are found out, which is necessary to minimize the measuring errosrs.

Productivity measurement has an important role in evaluating and establishing the next strategy in increasing productivity levels. This study aims to determine the level of productivity of a refined sugar company and provide suggestions for improvements to increase the level of productivity. This research uses the Objective Matrix (OMAX) method with five ratio indicators, namely yield achievement, actual production achievement criteria, boiler natural gas consumption criteria, electricity consumption criteria, and employee absenteeism criteria. This study uses company data for 2018 in accordance with company recommendations. The results showed that for one year, the productivity values and performance index differed each month. The performance index with the highest point was in February, which reached 426.3% and in May, which reached 306%. Based on the traffic light system, ratio 1 has six minimum performance periods, ratio 2 has eight minimum performance periods, ratio 3 has four minimum performance periods, ratio 4 has four minimum work periods, and ratio 5 has five minimum work periods. Improvement steps that can be done to improve the actual achievement of production are the provision of regular training to enhance skills and cooperation between operators, improvement of maintenance management systems, development of air circulation, and supplier evaluation. The OMAX method can identify performances that have below standard production, and recommendations for improvement can be prioritized on the ratio that experiences the most substandard performance.

In natural circulation loops, the driving force is usually low as it depends on the riser height which is generally of the order of a few meters. The heat transport capability of natural circulation loops (NCLs) is directly proportional to the flow rate it can generate. With low driving force, the straightforward way to enhance the flow is to reduce the frictional losses. A simple way to do this is to increase the loop diameter which can be easily adopted in pressure tube designs such as the AHWR and the natural circulation boilers employed in fossil-fuelled power plants. Further, the loop diameter also plays an important role on the stability behavior. An extensive experimental and theoretical investigation of the effect of loop diameter on the steady state and stability behavior of single- and two-phase natural circulation loops have been carried out and the results of this study are presented in this paper.

The article presents result of a research a system of the venting of exhaust gases of the recovery boiler the gas turbine plant through the natural draft cooling tower in the environment. The use of this scheme allows the fl ue gases to lower the temperature of the circulating water at the outlet of the cooling tower to provide a deeper vacuum in the condenser steam turbine combined cycle power plant with simultaneous reduction of capital to build chimneys. As a result of the application of this scheme, an increase in the absolute electric effi ciency of turbines is achieved. As stated in Article method of calculating the removal of exhaust fl ue gas systems with a perforated distributor ring allows to determine the level of engineering design and volume requirements of these systems.

Provision of passive means to reactor core decay heat removal enhances the nuclear power plant (NPP) safety and availability. In the earlier Indian pressurised heavy water reactors (IPHWRs), like the 220 MWe and the 540 MWe, crash cooldown from the steam generators (SGs) is resorted to mitigate consequences of station blackout (SBO). In the 700 MWe PHWR currently being designed an additional passive decay heat removal (PDHR) system is also incorporated to condense the steam generated in the boilers during a SBO. The sustainability of natural circulation in the various heat transport systems (i.e., primary heat transport (PHT), SGs, and PDHRs) under station blackout depends on the corresponding system's coolant inventories and the coolant circuit configurations (i.e., parallel paths and interconnections). On the primary side, the interconnection between the two primary loops plays an important role to sustain the natural circulation heat removal. On the secondary side, the steam lines interconnections and the initial inventory in the SGs prior to cooldown, that is, hooking up of the PDHRs are very important. This paper attempts to open up discussions on the concept and the core issues associated with passive systems which can provide continued heat sink during such accident scenarios. The discussions would include the criteria for design, and performance of such concepts already implemented and proposes schemes to be implemented in the proposed 700 MWe IPHWR. The designer feedbacks generated, and critical examination of performance analysis results for the added passive system to the existing generation II & III reactors will help ascertaining that these safety systems/inventories in fact perform in sustaining decay heat removal and augmenting safety.

The article is devoted to the one-hundredth anniversary of Teploelektroproekt Institute, and presents areas of the institute’s current activities. Despite the difficult conditions, the financial and economic crisis, the Institute continues to be one of the leading design organizations in the field of developing projects of thermal power plants operating on organic fuels (coal, natural gas, fuel oil) with the installation of steam-turbine, steam-gas, gas turbine units and substations of various voltages, in terms of its production capacity, technical equipment, scope of work performed and scale of orders received. The technical policy of the Institute is orientated at the future, the key objective being ensuring a high scientific and technical level of projects, and technical and commercial proposals developed by the Institute. The Institute uses cutting edge technologies in the development of technical documentation; introduces advanced technical solutions throughout the project and conducts its uniform policy for the projects under development; provides consistently high quality of technical documentation on the basis of continuous improvement of its quality management system; improves methods of calculation/mathematical models and their implementation in the design process; ensures comprehensive and total accounting of the Customer’s requirements at preparation of technical and commercial offers, design of new and/or reconstruction and technical re-equipment of existing power-generating facilities; maintains close relations with scientific and design organizations, manufacturers of equipment, products and materials for the purpose of introduction of available advanced scientific and technical achievements in project documentation. Standardized layouts of the main buildings are designed for pulverized coal-based generating units of ultra-supercritical steam conditions, for circulating fluidized bed boilers, flue gas denitrification and desulphurization plants, for combined cycle plants. Examples of the power plant designing are presented for industrial facilities utilizing nonconventional fuels. A short description is given about the institute’s references in the field of construction of combined cycle and cogeneration plants as well as pulverized coal-based plants.

The basic objective of the paper is to identify the desired circulation ratio for the natural circulation of water tube boilers in different operating conditions. This requires the basic study of heat flux and the mode of the boiling heat transfer, and the phenomenon like a departure from nucleate boiling and tube overheating. The parameters, which need to be studied are heat flux, pressure, dryness fraction, void fraction, liquid velocity and their impact on the required circulation ratio. The present work is to develop a circulation analysis model for the natural circulation of the water tube boiler and to check the boiler design for different failure modes. For a natural circulation boiler, the circulation ratio is one of the most important design parameters as the other design parameter like critical heat flux and skin temperature are mainly derived from the circulation ratio. The required circulation ratio can vary with the boiler pressure, liquid velocity and maximum heat flux. This study is intended to provide input for the safe and optimum design of a natural circulation boiler.

A model to predict the steady-state behavior of a rectangular two-phase natural circulation loop has been proposed. The analysis employs a one-dimensional two-fluid model to identify various system parameters, with particular emphasis on the subcooled boiling region. The onset of two-phase region and point of net vapor generation and associated liquid temperatures and vapor qualities have been estimated using a few widely recognized correlations. Predicted results demonstrate that the consideration of subcooled boiling may have significant effect on system behavior, particularly around the transition regions. The interaction of saturated bubbles and subcooled liquid and associated change in heat transfer and frictional forces has been discussed in detail. Fluid stream has been observed to have different combinations of flow stream conditions at boiler exit and condenser inlet. Five probable combinations have been identified and a generalized working-regime map has been proposed on Nsub−NZu plane. Attempts have been made to identify the influence of various control parameters. A favorable sink condition (higher coolant flow rate or lower coolant entry temperature) has been found to be of particular importance to attain a wider operating range of wall heat flux and better heat transfer characteristics. A design map has been proposed to identify favorable operating condition in terms of control parameters to ensure complete condensation.

Abstract In the present work, a numerical model is developed to analyze the riser-downcomer system of a natural circulation steam generator. The design and operation of the riser-downcomer system involve many complex issues such as multiphase flow inside the riser tubes, numerous possibilities of different flow regimes, and undesirable tube overheating due to the occurrence of critical heat flux (CHF). A separated flow model is developed to analyze steam-water two-phase flow inside the heated riser tubes. Further, the model is coupled with the implementation of the complex flow regime map and evaluation of wall temperature rise of the riser tubes. The present model is adequately validated with the existing experimental and numerical data as a direct problem. The model accuracy in predicting the tube dry-out and practical design is tested with the experimental data and real plant data, respectively. A typical 600 MW thermal power plant boiler is then investigated along with techno-economic efforts to find the possible design solutions of the boiler riser-downcomer circuit. The safe and unsafe zones of operations have been identified in the present study and, consequently, a range of feasible design solutions is provided in great detail. The diameters and thicknesses of the tubes used in the present analysis are in compliance with the ASME boiler code.

Nowadays, our life needs more and more electricity, and our lives cannot be without electricity, which requires our power to develop more quickly. Power plants are undoubtedly the place where electricity is produced. And now most of the power plant or chemical energy can be converted into heat, and then through the heat to do power production. The boiler is the main part of the power plant. Boiler unit consists of boiler body equipment and auxiliary equipment. The main body of the boiler consists of 'pot' (soft drinks system) and 'furnace' (combustion system). Baotou thermal power plant is mainly burning gas. The gas and air are at a certain rate into the furnace burning. This can greatly reduce the pollution of the environment, but also the full use of fuel. The soda system is mainly carried out in the drum. The heat generated by the combustion system heats the water in the drum, producing steam and then pushing the steam turbine into mechanical energy and finally into electrical energy. This has a high demand for water level, water composition, and the temperature of the steam produced in the drum. The water level should have upper and lower bounds, keeping it within a certain range. Water level is too high, will affect the steam drum soda separation effect, so that the steam drum exports of saturated steam with water increased, causing damage to the turbine, will cause serious explosion. And the water level is too low, it will affect the natural circulation of the normal, serious will make the individual water pipe to form a free water, resulting in flow stagnation, resulting in local metal wall overheating and burst pipe. Water in the heating at the same time will form a lot of scale, if not the chemical treatment of water will be in the formation of scale in the drum, cleaning more difficult, so the damage to the drum. The pressure of the drum is also an important control variable, and pressure control is highly correlated with liquid level control. It is necessary to ensure the integrity of the equipment, but also to ensure safety, followed by ensuring that the process of normal operation of the drum water. This time, the design is mainly for the unit steam temperature control system design. Steam temperature is one of the important indicators of boiler operation quality. It is too high and too low will significantly affect the power plant safety and economy. If the temperature of the steam is low, it will cause the power plant to increase the heat consumption and increase the axial thrust of the turbine to cause the thrust bearing to overload, but also cause the steam turbine to increase the final steam humidity, thus reducing the efficiency of the turbine, aggravating the erosion of the blade. On the contrary, the steam temperature is too high will make the super-heater wall metal strength decreased, and even burn the high temperature of the super-heater, the steam pipe and steam turbine high-pressure part will be damaged, seriously affecting safety. The boiler temperature control system mainly includes the adjustment of the superheated steam and the reheat steam temperature. The superheated steam temperature is the highest temperature in the boiler soda system. The stability of the steam temperature is very important for the safe and economical operation of the unit. Therefore, in the boiler operation, must ensure that the steam temperature in the vicinity of the specified value, and the temperature of the super-heater tube wall does not exceed the allowable working temperature.

Introduction. Dosimetric control revealed a significant decrease in the background level of ionizing radiation from tap water after boiling it in various household appliances. As natural doses of ionizing radiation are known to be necessary for the normal functioning of living organisms, it has been suggested that the boiling process may have an adverse effect on the biological properties of water. Materials and Methods. To confirm or refute the indicated assumption, the seeds of barley (Hordeum vulgare) were germinated on tap water, which was boiled in one of the household appliances (microwave oven, electric kettle, ordinary kettle), and measured the length of the roots and epicotyls in 4-day seedlings. Based on the data obtained, the average values of the respective indicators were calculated. Quantitative data were obtained on representative sample sizes and are statistically significant with a probability of 0.05. Results and Discussion. The data obtained during the experimental study indicate that boiled water had a positive effect on the growth of roots and epicotyls of barley seedlings. And if for epicotyls the differences in comparison with the control were statistically insignificant, then for the roots in all experimental variants of germination in boiled water was found a statistically significant increase in the average length of the roots compared to unboiled water (control). Thus, the average length of roots during germination of barley seeds in water boiled on a gas stove was 40.0 ± 4.1 mm, on water boiled in an electric kettle - 33.6 ± 4.6 mm and on water, boiled in a microwave oven, - 32,4 ± 3,5 mm, against 25,7 ± 4,9 mm in control. Thus, (i) boiled tap water, which was obtained in various ways, is able to stimulate growth processes during the germination of barley seeds; (ii) this phenomenon is observed in relation to root growth after all methods of water treatment; (iii) the greatest stimulation of root growth was caused by water boiled on a gas stove. In the second series of experiments to identify the possible effect of substances dissolved in tap water on its biological properties, a comparative analysis of the growth effects of unboiled tap water and distilled tap water (which underwent deep purification) was performed. The data obtained indicate that distilled water stimulates the growth of roots of barley seedlings comparative by unboiled tap water: when germinating barley seeds in distilled water, the average length of the roots of seedlings was 16.1 ± 3.33 mm, while in germinating on unboiled tap water - 9.35 ± 0.79 mm. The next stage of the study was to determine the effect of the level of water purification by boiling on the growth parameters of phytotest. The obtained results indicate that boiling distilled water on a gas stove helped to improve its growth qualities: seedlings grown on such water had an average root length more than 2 times higher than the control values. At the same time, distilled water, which does not underwent such treatment, stimulated less, albeit reliable, seedling root growth. Therefore, the level of tap water purification determines the appropriate degree of its stimulation of root growth processes of barley seedlings. Conclusions. Studies have shown a positive effect of boiled tap water on the average length of seedling roots. The magnitude of the effect depended on the type of device in which the boiling water was carried out. Boiled distilled water also promoted seedling root growth. Possible cause for improvement of growth qualities of water was removal or destruction in the process of boiling of gases and soluble substances which are either unfavorable for the growth of the plant organism or prevent the ice-like structures formation, in the microcavities of which are circulating monomers of water are available for aquapores of living organisms. At the same time, despite the growth-promoting effect, potentially boiled tap water may have mutagenic properties that the growth phytotest does not detect.

'The vital experience of the glad animal sensibilities made doubts impossible on the question of our speed; we heard our speed, we saw it, we felt it as a thrilling; and this speed was not the product of blind insensate agencies, that had no sympathy to give, but was incarnated in the fiery eyeballs of the noblest amongst brutes, in his dilated nostril, spasmodic muscles, and thunder-beating hoofs.' -- Thomas de Quincey (1849), "The English Mail-Coach" For Thomas de Quincey, the thrust of speed is intimately linked with the thrust of the body. Subjectivity is formed by and through a corporeal experience of acceleration. In this way, De Quincey has the jump on those other lovers of automated speed: the Italian Futurists. That heady clash of bodies, speed and information, or the technological sublime, we characteristically associate with the development of twentieth-century communication is already articulated some sixty years before Marinetti imagines the 'divine fusion' of body and machine. Thomas de Quincey's 1849 ode to the postal service -- "The English Mail Coach" -- functions as a significant text in modernity's velocity culture. Specifically, de Quincey allows us to historicise the critical terms of 'speed', 'body' and 'circulation'. This paper makes some preliminary historical observations about the acceleration of communication and transport systems and how this rapidity might give rise to new forms of subjectivity or the emergence of what Jeffrey T. Schnapp calls 'the kinematic subject'. The perceptual reconfiguration of time and space is central to an understanding of modernity's preoccupation with speed. Rapid data circulation through digital information systems means that distance appears to shrink and time seems to collapse. Manuel Castells calls this a 'new time regime' (429). Temporality now functions according to a double logic: a simultaneous binary of 'the eternal and of the ephemeral'. The contemporary 'manipulation of time' turns on 'instantaneity and eternity: me and the universe, the self and the net' (462-3). For David Harvey the defining feature of postmodernity is 'time-space compression'. Capitalism is 'characterised by speed-up in the pace of life, while so overcoming spatial barriers that the world sometimes seems to collapse inwards upon us' (241). Castells and Harvey are not, of course, the first to notice the degree to which the changing rhythms of a communication vehicle might impact upon perceptions of time and space. In 1909 Marinetti announces its demise: 'Time and Space died yesterday. We already live in the absolute, because we have created eternal, omnipresent speed'. Yet this death is prefigured some 120 years before by the 18th century author Hannah More in a letter where, quoting Alexander Pope, she illustrates her reaction to the introduction of the mail coach: I have just been thinking that if the amorous poet, who modestly wished to annihilate time and space had lived to see our fortunate days, he would have seen his prophetic visions realised... cards having well-nigh accomplished the first, and mail-coaches the last. (Qtd. in Lewis 264) This letter is dated 1788, only four years after the establishment of the mail coach system. Initially the service ran between London and Bristol so that Hannah More writing from Somerset would complain of being bypassed by this new mode of information circulation: Of the other blessing, the annihilation of space, I cannot partake; mail-coaches, which come to others, come not to me. Letters and newspapers, now that they travel in coaches like gentlemen and ladies, come not within ten miles of my hermitage. (265) More here identifies an important historical factor in the transformation of information networks. It concerns the coupling of transportation and communication: information travels 'in coaches like gentlemen and ladies'. In More's 18th century account the two remain connected while, as James Carey has noted, the significance of the 19th century's invention of the telegraph is that it splits the two processes. The telegraph 'allowed symbols to move independently of geography and independently of and faster than transport' (213). For de Quincey, a pivotal feature of the mail coach is the way in which communication and transportation function coextensively. Recounting his travels on the coach as it distributes news from the Napoleonic wars he notes that 'the grandest chapter of our experience, within the whole mail-coach service, was on those occasions when we went down from London with the news of victory' (290). For de Quincey, as for other commentators, the mail coach is a political instrument. Through the increasing efficiency of its communication infrastructure, it 'binds the nation together' (Austen 361). As de Quincey puts it 'the mail-coach, as the national organ for publishing these mighty events, thus diffusively influential, became itself a spiritualised and glorified object to an impassioned heart' (272). What impresses de Quincey most, however, is the speed of this vehicle. Or perhaps, more accurately, it is a particular relation between the self and speed, which confers on the mail coach a 'glory of motion' (270). By the time he publishes his essay, postal and newspaper circulation by mail-coach is nearly at an end. The last mail coach ceases action in London in 1846 (Daunton 123) and postal distribution begins to be carried out by rail. De Quincey clearly mourns the loss of this form of communication. And his regret depends on the self's perception of speed. That is, to qualify as an authentic act of transportation (of the body, of the post or of language), one must, to some degree, be aware of the systems of circulation, the modes of delivery and the vehicle of communication. One ought to be able to experience the speed at which one travels or the mail is delivered. The body must remain in contact with the message. In de Quincey's view the railway communication system fails for these sorts of reasons: The modern modes of travelling cannot compare with the mail-coach system in grandeur and power. They boast of more velocity, not however as a consciousness, but as a fact of our lifeless knowledge, resting upon alien evidence; as, for instance, because somebody says that we have gone fifty miles in the hour though we are far from feeling it as a personal experience ... . Apart from such an assertion, or such a result, I myself am little aware of the pace. But, seated on the old mail-coach, we needed no evidence out of ourselves to indicate the velocity. (283, emphasis in the original) Perched atop the careening mail coach, the self needs no secondary evidence to confirm its propulsion: 'we heard our speed, we saw it, we felt it as a thrilling'. But with the emergence of railway systems, the self somehow becomes cut off or distanced from the mode of transport: 'But now, on the new system of travelling, iron tubes and boilers have disconnected man's heart from the ministers of his locomotion' (284). To be sure, rail is faster. But that fails to impress de Quincey for the rail cannot offer him the same sublime effect. The mail coach is drawn by 'royal horses like cheetahs' (282) while the train lacks the power to raise even 'an extra bubble in a steam-kettle' (284). The sublimity of speed is also aural. But once again the railroad fails to inspire awe: 'the trumpet that once announced from afar the laurelled mail; heartshaking, when heard screaming on the wind ... has now given way for ever to the pot-wallopings of the boiler' (284). In Burke's formulation of the sublime there is danger and terror but there must also be a certain distance from this threat. It is 'simply painful' when we are aroused by causes that 'immediately affect us' but it is sublime when 'we have an idea of pain and danger, without being actually in such circumstances' (51) . For de Quincey sitting inside the carriage seems to offer too much safety and distance, the interior reserved as it is for the 'porcelain variety of the human race' (273). Instead, he travels aloft near the driver because of 'the air, the freedom of prospect, the proximity to the horses, the elevation of seat' (275). And he has the possibility of reining them in himself: 'the certain anticipation of purchasing occasional opportunities of driving' (275)1. The closer he is to the ministers of his locomotion, the better de Quincey likes it. The more he becomes the agent of his own speed, the more immediate, authentic and sublime seems his journey. For de Quincey, then, the superiority of the mail coach over the railroad lies not in terms of absolute speed but rather it concerns issues about the body's experience of and relation to that speed. As Matthew Schneider (1995) puts it 'the difference between the two with respect to their speed, privileges mail coaches by virtue of their violent immediacy, their ability to transmit the actual or living sensations rather than one that is intermediate or representational' (152)2. In a fascinating paper about the correlation between speed and subjectivity Jeffrey T. Schnapp identifies the mail coach in general and de Quincey in particular as emblematic of an 'inaugural moment' in the development of an 'anthropology of speed' (3). With a quick side swipe at the ahistorical and apocalyptic underpinning of Paul Virilio's Speed and Politics, Schnapp argues that although speed has always been 'an agent of individuation' it is with modernity that it begins to depend on the relation between self and vehicle: ... the mere experience of riding on horseback was not enough to establish a modern culture of velocity. Speed's rise as a cultural thematic, its move into an everyday realm of perceptibility, its adoption as sacrament of modern individualism, became possible only with the development of mechanical buffers between rider, horse, and roadway: buffers that enable new fantasies of attachment, first, between rider and engine, and, then, according to a more complex logic, between rider, engine, vehicle, and/or landscape. (10-1) What is particularly productive about Schnapp's account is that he schematises the history of transportation in terms of the relation between speed, body and vehicle. For Schnapp this is a pivotal dynamic. De Quincey's equestrian desire and his disdain for railroad travel, is part of a historical process where individuality comes to be 'identified with administration of one's own speed' (14). In Schnapp's model, there are 'two concurrent yet distinct experiences of velocity', one that he calls 'thrill-based' and the other 'commodity-based'. The first is experienced in modes such as on top of the mail-coach and later, cars, motorbikes and aeroplanes. 'Commodity-based' refers to train and bus travel. The difference between the two is that thrill-based transportation occurs when the passenger 'can envisage himself as the author of his velocity' while in 'commodity-based' forms the traveller is 'shielded from the natural environment and the engine, and passively submits himself to velocity' (18-9). De Quincey's essay is a valuable resource for communications historiography. Like Jacques Derrida, he recognises how the rhythms of the postal service function to construct identity. As a system of circulation and exchange, the post office institutionalises modes of correspondence, producing and regulating particular subjectivities. And like Postman Pat, de Quincey knows the corporeal pleasures of delivering the mail. Footnotes There are also issues of class at work here. Tickets were more expensive to sit inside the carriage which de Quincey, then a student at Oxford, could not afford. He attempts to reverse these class distinctions by arguing that 'inside which had been traditionally regarded as the only room tenantable by gentlemen, was, in fact, the coal-cellar in disguise' (187). The secondary material on de Quincey is quite extensive. In the last 15 years his work has been investigated from a number of different angles including poststructuralist approaches to language and his transitional status as a figure between Romanticism and Modernism. As well as Schneider, see Clej and Snyder. References Austen, Brian. British Mail-Coach Services 1784-1850. New York and London: Garland, 1986. Burke, Edmund. A Philosophical Enquiry into the Origin of Our Ideas of the Sublime and Beautiful. Ed. James T. Boulton. 2nd ed. Oxford: Basil Blackwell, 1987. Carey, James W. Communication as Culture: Essays on Media and Society. Boston: Unwin Hyman, 1988. Castells, Manuel. The Information Age: Economy, Society and Culture. Volume 1: The Rise of the Network Society. Cambridge, Massachusetts: Blackwell Publishers, 1996. Clej, Alina. A Genealogy of the Modern Self: Thomas De Quincey and the Intoxication of Writing. Stanford: Stanford UP, 1995. Daunton, M.J. Royal Mail: The Post Office since 1840. London: The Athlone Press, 1985. De Quincey, Thomas. "The English Mail-Coach." The Collected Writings of Thomas De Quincey. Ed. David Masson. Vol. 13. Edinburgh: Adam & Charles Black, 1890. Derrida, Jacques. The Postcard: From Socrates to Freud and Beyond. Trans. Alan Bass. Chicago: U of Chicago P, 1987. Harvey, David. The Condition of Postmodernity: An Enquiry into the Origins of Cultural Change. Cambridge, Massachusetts: Blackwell Publishers, 1990. Lewis, W.S., ed. Horace Walpole's Correspondence. Vol 31. New Haven: Yale UP, 1961. Marinetti, FT. "The Founding and Manifesto of Futurism." First published 1909. Futurist Manifestos. London: Thames and Hudson, 1973. Schnapp, Jeffrey T. "Crash (Speed as Engine of Individuation)." Modernism/Modernity 6.1 (1999): 1-49. Schneider, Matthew. Original Ambivalence: Autobiography and Violence in Thomas De Quincey. New York: Peter Lang, 1995. Snyder, Robert Lance, ed. Thomas De Quincey Bicentenary Studies. Norman: U of Oklahoma P, 1985. Virilio, Paul. Speed and Politics: An Essay on Dromology. Trans. Mark Polizzotti. New York: Semiotexte, 1986. Citation reference for this article MLA style: Ester Milne. "'The Ministers of Locomotion': Some Historical Speculations on Velocity Culture." M/C: A Journal of Media and Culture 3.3 (2000). [your date of access] <http://www.api-network.com/mc/0006/ministers.php>. Chicago style: Ester Milne, "'The Ministers of Locomotion': Some Historical Speculations on Velocity Culture," M/C: A Journal of Media and Culture 3, no. 3 (2000), <http://www.api-network.com/mc/0006/ministers.php> ([your date of access]). APA style: Ester Milne. (2000) 'The ministers of locomotion': some historical speculations on velocity culture. M/C: A Journal of Media and Culture 3(3). <http://www.api-network.com/mc/0006/ministers.php> ([your date of access]).

The contemporary supermarket is a work of classification and cataloguing as marvellous as any museum. Barcodes are hallmarks by which its computer systems could know, in their own electronic language, every possible product of a certain kind afoot in the nation. It is a rather special institution in this respect -- a huge fund of contemporary synchronic cultural memory, a database and storehouse of collected human tastes to which individuals turn to seek out their own. However, this means that just as Wittgenstein demonstrated the impossibility of a purely private language, there can be no such thing as a purely private taste. Taste is demonstrated by choosing from a range of public items, that is, products. Therefore let's bracket the liberal concept of sovereign personal taste for now and beat a different track: the supermarket is the site of aggregation of multiple discourses by which the individual is sewn into and sews the fabric of collective life. Techniques used to sell food today, such as freebies (like plastic toys), free offers, forms of gambling, and images of healthiness, convenience, celebrity and enhanced relationships, appeal to -- must appeal to for commercial reasons -- shared values. It is inviting to view the supermarket as an emblem of a postmodern condition. The gaggle of images and words that line its aisles defy unity, play fast and loose with reality, create a simulacral space of copied quotes and sight bites that is coterminous with radically decentred selves. It conforms to the Jamesonian topography of a culture that has lost it -- that sense of real placed history that identity used to be tied up with. But my aim in this essay is to critique such a rhetoric of loss. Discourse remains the province of the self-imaginings of social groups in spite of the diversity of images in circulation. And although the media through which group solidarity is transmitted change with technological developments, the fact of such transmission does not. Hence, by looking at the imagery used on food packets, I will analyse the way that one rhetorical strategy used to sell the food we find on supermarket shelves -- nationalism -- is part of a longstanding cultural trajectory by which citizens of a nation imagine their relationship with their land. This, however, involves the equation of 'the nation' with the ethnic imagery of the group that dominates its political apparatus and territory, a process of circumscription that I shall ultimately suggest has political ramifications, especially in the context of nations like Australia which were formed by largely European settler colonisation of the land. Nationalism, then, is a strand of marketing rhetoric used most often, but not exclusively, for the promotion of products in the country of their origin. As such it grafts a tradition of art commemorating place and ethnic identity into the seemingly unlikely genre of the product label. Indeed, for Benedict Anderson the sociopolitical sentiment of nationalism requires forums and images through which to articulate itself, or more accurately, to imaginatively create its auratic object of adoration -- as nationalism is itself innovative (Anderson 15). It also depends upon technologies that can produce a sense of simultaneity between dispersed people who will never meet each other. The distribution of the packaged 'gifts' of a land to 'its people' provides one such opportunity for the transmission of sacralised images of land and the solidarity of its inhabitants. So the genre of the label that comes with a specific distribution and selling system provides the technical medium, and the land, its produce, its people and their relationships in ecosocial community, form the imagery. A limit case example of pride in the gifts of the land can be found on the label of New Zealand's Steinlager: "New Zealand's Finest ... World's Best Lager ... Brewed with the finest New Zealand Hops, Yeast, Barley and Pure Water ... Since 1854". It embodies a series of associations found in other examples: the products of the land are associated with firstly, high quality, and secondly, natural purity. New Zealand seems to be repeated with two slightly different senses. In its juxtaposition with "the world", the two places centre on the finished product of lager, which is presented as a literally world-beating national product. The last line of the label reads "Brewed and Bottled by New Zealand Breweries Limited", the company name both emphasising the agency of New Zealand people in processing ingredients taken from their land's soil, and the legally New Zealandian status of their enterprise. The second sense implies the physical basis for all this: the giftedness of the land which subtends an economy and a culture. "Since 1854" brings these components together on the axis of continuity, making the origination of national production temporal as well as spatial. In other words this benign relationship of production becomes part of national heritage. A certain double sense is in play. Land is both a nation comprising citizens and physical resource; the word that perfectly fuses the sense of the former's political proprietary relationship with the latter into a working unity. Accordingly many packets transfigure the legal requirement to mention the place of production into an attention-grabbing declaration of country of origin whilst also referring to the physical land. The latter may be parsed into two general categories: imagery of animals, plants, landscapes, the elements, etc, and rustic images of human management of the land. So Bulla ice cream advertises its Australianness to a pastoral backdrop; Saxa salt, which has been "Australia's own ... Since 1911", is being hauled by a hat-wearing Aussie man and loyal horse; Bundaberg caster sugar is both "pure Australian" and "Australian made" thanks to the blessing of the (Australian) sun. And other products, such as Australian Natural Foods Non Dairy Soy Mango Smoothie and Pureland Organic Tofu make links between nation and nature through 'land-based' company names similarly buttressed by images of Australian agricultural landscape and the Australian made hallmark respectively. The three conceptual categories often found in correlation with the concrete particulars of 'the land' -- healthiness, purity and naturalness -- are well represented in the packets analysed here. A series of metonymic implications is set up between the terms. They are all potential qualities of the land that are realised in the products it yields. Pureland and Australian Natural Foods juxtapose nation and healthiness closely and the pastoral visions of Bürgen and Dairy Vale have the approval of the National Heart Foundation. Bundaberg and Pureland make the most direct appeals to purity, but concepts such as Bulla's "Australian made real dairy" and Devondale's "choice grade" and "premium Australian" also convey a certain sense of uncorrupted pedigree in their products' provenance. Most products seem to evoke naturalness pictorially, with green rolling landscapes and cows feeding on the verdure featuring particularly highly. Thus at this point a critique of capitalist industrial culture is possible. The missing links are the contemporary factory and office: the places of the processing and assembly of the product physically and discursively; the places where the fruits of the land meet their packaging and are primed for the marketplace. The gifts of nature become commodities but are inscribed as the gifts of nature still, such that the point of sale obfuscates the point of production: profit. The whole enterprise seems to be based on a principle of distantiation. Because of urbanisation, the vast majority of people live away from farm land, and because most food is not consumed by the local communities that produce it, but is produced for larger markets, it is packed and written upon for transport to strangers who will buy it and perhaps also an idealisation of the land. Yet they aren't strangers. This mediation of group solidarity by food-as-commodity does not tear social bonds apart, it forms them. It forms ecosocial community just as it provides a projection of one. And the very invocation of group loyalty as the reason for buying means we should question, as John Frow has done, whether the commodity is always simply a token of abstraction in conceptual opposition to 'the gift' (Frow, "Gift and Commodity"). It is not simply the case that capitalists dupe consumers into thinking of commodities in gift-like terms. Indeed, the discourses of the land we find on supermarket shelves go back a long way in Western culture. As Raymond Williams says: "in English, 'country' is both a nation and a part of a 'land'; 'the country' can be the whole society or its rural area. In the long history of human settlements, this connection between the land from which directly or indirectly we all get our living and the achievements of human society has been deeply known" (1). The majority of the packets analysed extend the pastoral tradition of European art, a tradition which determines the "innate bounty" (33) of the land as the province of benign, 'total' social relations as reflected in the "timeless rhythm" of the authentic agrarian life (10). But the pastoral tradition is itself a media technical one. Williams points out that "a working country is hardly ever a landscape. The very idea of landscape implies separation and observation" (120). The same is true of pastoral in its nationalistic guise. It is transmitted by books, paintings and packets, is predicated on such a 'separation and observation'. The idealisation of the common land that subtends 'us' may be an attempt to bridge that distance, yet it is, ironically, transmitted through inscribed objects that create bonds between spatially and temporally dispersed people. It achieves what Anderson calls "unisonance", "a special kind of contemporaneous community which language alone suggests -- above all in the form of poetry and songs" (132). So, if the supermarket turns inner desire outward to the realm of public items that provides its possibilities, nationalistic desire moves in the same way, both inside and outside the supermarket context. There is no purely internal or purely external nation, just as there is no private language. Rather cultural memory, whether transmitted by a food packet or a poem is a thread transmitted through selves, language, technological milieux, and groups of people. Thus as Thongchai Winichakul succinctly states, "a nation is not a given reality. Rather it is the effect of imagining about it" (14). "We can know about it as long as we employ certain technologies to inscribe the possible sphere. In turn, such technologies create the knowledge of it, create a fact of it, and the entity comes into existence." (15). The contemporary food packet is one such media technology as certainly as a book or a song, and all media inscriptions of the possible sphere of 'the land' are lived ecosocial experience of the land. They make the land a unity by fusing its first physical sense with its second sociopolitical one. Invocation of the land as a prior given that subtends and provides the continuity of a sociopolitical group that has power over its resources, nests the historical contingency of that power relationship into a secure vision of the provenance of nation with the self-origination of 'its' land. That natural element, free, pure and healthy, is the one in which the group's ownership rights are rooted and legitimated. However, in fact, any nation is itself an historical innovation, an inherently unstable ideological product of strategy, technique, rhetorical and material. Nation-states are not naturally correlative with the land, nor are the ethnic groups that politically dominate the nation. They arise where other socio-economic political organisations existed before; they emerge. In The City and the Country Williams's main concern was to point out an alternative class-based history of the real and largely exploitative management of the land, a history that is actively occluded by idealised renderings of the countryside. Here in a parallel way but without room for explication, I want to suggest an alternative history of the management of the land that is indissociable from the emergence of the modern Australian nation -- a race-based history. Thus, here's the rub: the totems of pastoral that are equated with Australianness in the packets I have referred to, are European. The 'food packet' pastoral idealises group totems such as to transform historically contingent relationships of certain ethnic groups with the land into naturalised ones. The cows of Bulla and Devondale, the pastures of Dairy Vale, Bürgen's wheat, the agricultural infrastructure, the men imaged and their modes of management of the land, are European in lineage, and so is most of the food they sacralise as 'Australian'. These things are not natural to the land but were introduced, as was a related political and economic infrastructure that created 'Australia'. And there is a whole history to this appropriation of the land that is not active in the rhetorical force field of the European Australian pastoral, just as the living cultural memories of Aboriginal peoples disposed by the creation of the Australian nation-state are not. ... In "Australia Day at the Aboriginal Tent Embassy", Felicia Fletcher and John Leonard mention how representatives of Aboriginal countries in Australia assembled at Parliament House eat food to sustain themselves in their bid to right this dispossession: "vegetables are cooked in the coals, bread is toasted over the fire, endless cups of tea are poured, pots of three dozen eggs are boiled again and again to keep up the strengths and spirits of the people" (16). However, they add, quoting the group rather than a specific individual: "'It's nice, but at home we'd have a nice bit of kangaroo tail in the fire -- you've got to know how to do it properly -- and damper'": a different memory of and relationship with 'the land' (in both its senses). To conclude, the memories of the land create it at the time of commemoration. How we commemorate it is a present-day matter of great communal and political significance. Plates 1 Ducks Nuts 7 Bürgen High-Bake Heritage White bread 2 Steinlager Beer 8 Devondale Extra Soft margarine 3 Bulla Real Dairy Ice Cream 9 Bundaberg Caster Sugar 4 Saxa Table Salt 10 Dairy Vale Skim Milk 5 Pureland Organic Tofu 11 Devondale Cheese 6 So Natural Mango Smoothie 12 Edgell References Anderson, Benedict. Imagined Communities: Reflections on the Origin and Spread of Nationalism. London: Verso, 1983. Fletcher, Felicia, and John Leonard. "Australia Day at the Aboriginal Tent Embassy." Meanjin 58.1 (1999): 10-17. Frow, John. "Gift and Commodity." Time and Commodity Culture: Essays in Cultural Theory and Postmodernity. Oxford: Oxford UP, 1997. ---. "Toute la Mémoire du Monde: Repetition and Forgetting." Time and Commodity Culture: Essays in Cultural Theory and Postmodernity. Oxford: Oxford UP, 1997. Williams, Raymond. The Country and the City. London: Chatto & Windus, 1973. Winichakul, Thongchai. Siam Mapped: A History of the Geo-Body of a Nation. Chiang Mai: Silkworm Books, 1994. Citation reference for this article MLA style: Guy Redden. "Packaging the Gifts of Nation." M/C: A Journal of Media and Culture 2.7 (1999). [your date of access] <http://www.uq.edu.au/mc/9910/gifts.php>. Chicago style: Guy Redden, "Packaging the Gifts of Nation," M/C: A Journal of Media and Culture 2, no. 7 (1999), <http://www.uq.edu.au/mc/9910/gifts.php> ([your date of access]). APA style: Guy Redden. (1999) Packaging the gifts of nation. M/C: A Journal of Media and Culture 2(7). <http://www.uq.edu.au/mc/9910/gifts.php> ([your date of access]).