Ecke, O. G. (Deutsche Shell Aktiengesellschaft, Ingolstadt, Federal Republic of Germany) | Dreyhaupt, F. J. (Ministerium für Arbeit, Geshundheit und Soziales des Landes Nordrhein-Westfalen, Dusseldorf Federal Republic of Germany)
ENVIRONMENTAL PROTECTION POLICY AND MEASURES TO REDUCE HYDROCARBON EMISSIONS FROM OIL REFINERíES Abstract Legal regulations and technical procedures used to judge the impact of hydrocarbon emissions by an oil refinery on the environment are described. Based on a survey of all hydrocarbon emission sources of a refinery, the fraction of the immission level caused by the refinery to the neighbourhood can be predicted by means of propagation calculations. By comparison of measured and calculated immission values against the official immission limit values, the significance of the refinery's emissions can be judged. The conditions which have to be fulfilled to obtain the permit from the authorities can then be formulated. Résumé On expose les règlements légaux et les procédures techniques utilisées pour évaluer l'influence sur l'environnement des émissions d'hydrocarbures prove- nant d'une raffinerie de pétrole. D'après une analyse de toutes les sources d'émission d'hydrocarbures d'une raffinerie, on peut prédire, au moyen de calculs de propagation, la fraction du niveau d'immission causée au voisinage par la raffinerie. En comparant les valeurs d'immission mesurées et calculées avec les limites officielles d'immission, on peut évaluer l'importance des émissions de la raffinerie. Ceci permet de formuler les conditions à remplir pour obtenir un permis des autorités compétentes. 1.
The paper discusses the legislation for environmental The Federal Republic of Germany is a country with protection now in force in the Federal Republic of considerable environmental problems, which are due Germany and the measures being taken to limit not only to its high degree of industrialisation, but also hydrocarbon emissions. Moreover, a regulation for to the fact that industry is concentrated in certain refineries in force in the Federal State of North Rhine- highly populated areas. Westphalia is reported. The paper indicates the effect Today's society recognises these problems and is of new regulations on the construction of refineries questioning the premise that pollution must increase at and stresses the need for authorities and governments the same rate as industry grows. Now, it is not only in their long-term planning to ensure the availability of necessary to redress the mistakes of past neglect, but suitable sites for future developments within reasonable also to consider the requirements necessary for future distance of markets and labour force. industrialisation with respect to technological develop- - ment, emission control and, above all, overallplanning. by H. O. G. ECKE, The complexity of the problems associated with Deutsche Shell Aktiengesellschaft, environmental protection, and the impossibility of Rafinerie Ingolstadt, isolated solutions, all compel not only close 807 Ingolstadt, Postf
Christianovich, S. A. (Institute of High Temperatures, Moscow, U.S.S.R.) | Maslennikov, V. M. (Institute of High Temperatures, Moscow, U.S.S.R.) | Pisman, M. K. (Institute of High Temperatures, Moscow, U.S.S.R.)
POWER STATIONS BASED ON PARTIAL OXIDATION OF RESIDUAL FUEL OILS. PART I:
AND ALTERNATIVE SCHEMES Abstract This paper describes a method for the multi-stage combustion of high-sulphur residual fuel oils in ther- mal power stations which ensures minimum contamin- ation of the atmosphere. In the first stage of com- bustion high-pressure steam and fuel gas are produced. The latter is cooled and freed of ash and sulphur compounds. The steam and the purified gas are then used for power generation. The method gives a high rate of sulphur removal and considerable reduction of nitrogen oxide emission. This new power station concept employs gas tur- bines and steam/gas turbines to obtain an optimum use of energy. A discussion of its technical and economic aspects concludes the paper. Résumé Cette communication décrit un procédé de com- bustion en plusieurs étapes des fuels oils résiduaires à haute teneur en soufre dans les centrales thermiques permettant de réduire à un minimum l'émission de polluants dans l'atmosphère. Au cours de la première phase de la combustion, on génère de la vapeur à haute pression et on produit un gaz combustible. Ce dernier est refroidi et débarrassé des cendres et composés sulfureux. La vapeur et le gaz combustible épuré sont alors utilisés pour la production d'énergie électrique. Cette méthode permet d'atteindre un haut degré de désulfuration et une réduction considérable des émissions d'oxyde d'azote. Les centrales électriques de cette conception nou- velle mettent en oeuvre des turbines à gaz ou des combinaisons de turbines à gaz et de turbines à vapeur de façon à obtenir une utilisation optimale de l'énergie. On termine la communication par une dis- cussion des aspects techniques et économiques des schémas proposés. 1.
combined power generation cycles employing gas and steam-gas turbines entailing cuts in construction costs for power plants. These savings in power generation, even for cur- rently operable temperature levels of working sub- stance before it reaches the gas turbines, can make up the additional "clean" fuel costs and, as the paper shows, the cost of power at such plants preventing undesirable exhausts to the atmosphere could be lower than with modern steam-turbine power plants dis- charging wastes to the atmosphere. Besides, there are realistic prospects of substantially raising the working substance temperature before it reaches the gas turbines which would significantly increase their efficiency and reduce electricity costs, whereas the efficiency of steam-turbine units for a long time has remained stable at a certain level which proves that in this respect they are close to their limit. As a result of thermal power stations burning tra- ditional energy fuels: coal and residual fuel oil, con- taining sulphur and ash, a lot of sulphur compounds and fly ashes, undesirable for people and the environ- ment, are
TECHNOLOGY AND ECONOMICS OF CLEAN FUEL GAS MANUFACTURE FROM LIQUID PETROLEUM Abstract The paper summarises alternatives for the conver- sion of liquid petroleum products of medium to high sulphur content into clean gaseous fuels. It compares the techniques used and the process economics applic- able to the manufacture of lean gases and substitute natural gas from a range of liquid fuels, i.e. LPG, naphtha, middle distillates, fuel oil and crude oil. It concludes that whilst naphtha reforming for SNG production will be a first choice on grounds of lowest investment and gas service costs, the gasification of crude oil and fuel oil for lower calorific value fuel gases may also find wide application. In the longer term coal as a raw material, at least in the US, seems likely to replace both light and heavy liquid fuels. Résumé Cette communication passe en revue les différentes possibilités envisageables pour la transformation de produits pétroliers liquides, à teneur en soufre élevée ou moyenne, en combustibles gazeux propres. Elle compare les technologies et l'économie des procédés utilisés pour la fabrication de gaz pauvres, de gaz de ville et de gaz naturel de substitution à partir de plusieurs combustibles liquides, les GPL, le naphta, les distillats moyens, les gas oils, le mazout et le pétrole brut. On conclut qu'en raisons des disponi- bilités, l'utilisation du pétrole brut augmentera, mais que la méthode la plus économique de gazéification est le reformage du naphta. A long terme, cependant, la houille remplacera comme matière première, au moins aux Etats-Unis, à la fois les fractions légères et les fuels lourds. 1. PURPOSE OF GASIFYING Liquid petroleum fuels by comparison with gaseous fuels have a number of drawbacks including a greater tendency towards incomplete combustion, cracking and carbon formation instead of complete combustion to gaseous products. Therefore, gaseous flames are more adjustable in size and shape than liquid fuel flames, and the minimum oxidant demand to ensure complete combustion is usually lower for gases. In addition, most gases are inherently "cleaner", i.e. contain less non-hydrocarbon material, specifically sulphur compounds, than liquid fuels, and any im- purities can be easily and effectively removed by vari- ous processes. Furthermore, the chemical composition of gaseous fuels is simpler than that of liquid fuels. Normally no more than four or five chemical species ~ ~ by W. L. LOM, ,formerly Senior ScientiJic Associate, Esso Research Centre, Abingdon, Oxon., England, and P. J. AGIUS, Director of Research, Esso Petroleum Company Ltd, London, S. W. 1, England will be present and it is thus much easier to react a petroleum gas to produce various petrochemicals than to produce chemical derivatives from liquid hydrocarbons. Finally gaseous fuels are more readily distributed by pipeline, even at low flow rates, to points of consumption. Consequently, the purposes of gas
DISCUSSION SPECIAL PAPER-THE NEW METHODS OF PURIFICATION AND STABILISATION OF THE OIL AND OIL REFINERY PRODUCTS BY THE LOW VALENT TRANSITION METAL COMPOUNDS Chairman : K. KUBOTA (JAPAN) Scientific Secretary: H. OZAKI (JAPAN) Professor K. AOMURA (University of Hokkaido, Japan) questioned the effects of the electronic structure and steric structure of metal molecules on reaction speed in such treatment. The reply was that the reaction speeds of iron carbonyls are faster in the order of dodecacarbonyl, nonacarbonyl and penta- carbonyl. Mr H. W. GROTE (Nikke Universal Co., Japan) and Mr. A. G. LICKUS (Process Division, Universal Oil Products Co., U.S.A.) raised several questions regarding the possibility of commercialisation of this process in the USSR, and the expected treating cost of petroleum products by this process in the USSR, referring to $8.50 of calculated iron pentacarbonyl cost per ton of kerosine treated, based on $3.30 per kg of this reagent in truck load quantities in the USA. This means the treating cost by such process would not be cheap in comparison to the value of the treated products. Mr K. NANIWA (Idemitsu Kosan Co., Japan) and Mr R. N. LUCAS (Petrolite Corp., U.S.A.) questioned the performance of motor gasoline and diesel fuel oil, treated by this process, in engines, They pointed out the possibility of harmful effects of dissolved metal compounds in treated hydrocarbons on engine performance. 223 D THERMAL CRACKING OF RESIDUAL OILS USING SUPERHEATED STEAM AND APPLICATION OF THE PRODUCTS Chairman: J. LIMIDO (FRANCE) Scientific Secretary: S. SUZUKI (JAPAN) Page SP 8 Thermal Cracking of Residual Oils Using Superheated Steam and Application of the Products Shimpei Gomi (Kureha Chemical Industry Co. Ltd, Tokyo, Japan), Ryoichi Takahashi (Eureka Industry Co. Ltd, Tokyo, Japan), Yoshio Kiritani (Sumikin Coke Co. Ltd, Wakayama PreJ, Japan), Yasuo Amagi and Yasushi Nishimura (Taiyo Kaken Co. Ltd, Japan) 227 DISCUSSION 239 225 T
VACUUM GAS OIL CRACKING Abstract A steam cracking plant designed to produce olefins from vacuum distilled heavy gas oils boiling in the range of 700-1000" FVT was started up in 1967 by Esso Chimie, an affiliate of Exxon Chemical, at Port Jerome, France. The plant was sized to produce 200000 metric tons per year of ethylene. The paper will describe the facility, its performance and special features installed to handle the high coke make. Olefins and by-product yields, investment and operating costs will be compared with steam cracking of naphtha feed. Environmental considerations will also be presented. Résumé Une unité de cracking à la vapeur pour la production d'oléfines à partir de gas-oil lourd provenant de la distillation sous vide à été démarrée en 1967 à Port- Jérôme par Esso Chimie, filiale de Exxon Chemical. Le gas-oil sous vide est une coupe 370-540°C et l'unité a une capacité de production d'éthylène de 200000 tonnes par an. L'article décrira l'unité et ses performances, ainsi que les caractéristiques particulières exigées par la production importante de coke. Les rendements en oléfines, en produits secondaires et les coûts d'investissement et d'opération seront comparés avec ceux du cracking à la vapeur d'un naphta. Les considérations concernant la protection de l'environ- nement seront aussi présentées. 1.
Twenty-five years of experience with steam cracking of atmospheric gas oils led to the design and construc- tion of the Port Jerome vacuum gas oil cracking unit. Even so, steam cracking a 370/535"C vacuum gas oil represented a considerable departure from previous experience. This paper will describe the facility, its performance and special features. In addition, a comparison of yields, plant investments and operating costs will be made between vacuum gas oil steam cracking and naphtha steam cracking. The vacuum gas oil steam cracking plant described in this paper was started up by Esso Chimie, an affiliate of Exxon Chemical, at Port Jerome, France, in 1967. It is of historical interest that the first com- mercial test of gas oil steam cracking was made at the same site in 1939. The early test was made in a conventional thermal cracking coil that was repiped for steam addition. Following the test, design work for the first commercial gas oil steam cracking plant began and the first unit went onstream at Baton Rouge, Louisiana, USA, in September, 1941. The first unit had a feed rate of 140000 tons/year of a 20O/40O0C atmospheric gas oil. A second gas oil cracking unit, almost three times the size of the first, followed within two years, and gas oil has been a major feedstock in our plants ever since. Today, our company and its affiliates combined produce about 2500000 tons/year of ethylene, of which approximately half comes from gas oil c
RECENT ADVANCES IN UNDERSTANDING THE EFFECTS OF OIL IN THE MARINE ENVIRONMENT Abstract Results of a four-year API programme on the fate and biological effects of oil spilled in marine environ- ments are summarised. This programme, involving a wide variety of marine species at all life stages, relies heavily on chemical analysis of the water column, Sediments and marine organism tissues for petroleum fractions. Conclusions from classical laboratory work must be tempered by considerations of volatility, solubility and persistency as affected by time. Evidence is presented that negates the widespread concern that marine organisms concentrate petroleum fractions indefinitely and pass them up the food chain. Rksumé On résume les résultats d'un programme API de quatre ans sur le sort et les effets biologiques de pétrole déversé dans le milieu marin. Ce programme qui comprenait l'étude d'une grande variété d'espèces marines à différents stades de leur évolution, était principalement basé sur l'analyse chimique des frac- tions pétrolières présentes dans l`eau, des sédiments et des tissus des organismes marins. Les conclusions des travaux classiques de laboratoire doivent tenir compte de la modification dans le temps de la volatilité, de la solubilité et de la persistance des hydrocarbures. On démontre que l'idée largement répandue selon laquelle les organismes marins concentrent indéfiniment les hydrocarbures et les introduisent dans la chaîne alimentaire est fausse. 1.
Without doubt, oil has been spilled in marine waters sporadically ever since the early days of the petroleum industry. Even before there was an industry, there were natural oil seeps. Johnson' details the locations of seeps in such places as Alaska, the California coast, the Gulf of Mexico, Newfoundland, the Atlantic coast of Central America, the shores of South America (especially the northern area), Africa, Asia Minor, and islands in the South and West Pacific. Currently, the total input of oil from all sources into the oceans is estimated at slightly more than six million metric tons per year, of which one-tenth comes from natural seeps. During World War II, substantial quantities of oil or oil products spilled from sunken tankers throughout the world. Especially numerous were tanker sinkings in the coastal waters of Louisiana and along the east by E. W. MERTENS, Chevron Research Company, Richmond, California, U.S.A., and L. P. HAXBY, Shell Oil Company, Houston, Texas, U.S.A. coast of Fl~rida.~ Most of these were the 16750-ton capacity T-2 tankers. When sunk, many were fully laden, and thus, their entire cargo of about 100000 barrels ultimately was imposed upon the local marine community. In contrast, less than 3000 tons were spilled by the tanker collision in San Francisco Bay in January 1971. After World War II, the quantity of peacetime tanker spills surely increased as the world became more dependent upon oce
INTEGRATED PLANNING FOR EXPLORATION7 DEVELOPMENT7 PRODUCTION AND TRANSPORTATION FOR RAPID EXPANSION OF OIL FIELD OPERATIONS Abstract This paper deals with the experience in theintegrated planning of search and exploration, oil-field develop- ment and exploitation and also trunk line transport in West Siberia, which is one of the largest oil- and gas-bearing provinces in the world. Because of its rich oil reserves and favourable geological field structure, West Siberia has become one of the main oil-producing regions in the Soviet Union. The high rate of oil-production growth with the severe natural climatic conditions in this area was the result of using new scientific and technical achieve- ments in developing the oil fields. The principal decisions of actual problems concerning well drilling techniques and technology and field exploitation are discussed in this paper. Great attention is paid to the accelerated con- struction of oil trunk lines with lengths up to 2000 km and pipes up to 50-in diameter. Résumé Cette communication traite de l'expérience acquise dans la planification intégrée de la prospection, du développement et de l'exploitation des gisements pétrolifères et du transport à grande distance par oléoduc du pétrole de la Sibérie Occidentale qui est l'une des régions du monde les plus riches en pétrole et en gaz. Ses grandes réserves et une structure géologique particulièrement favorable ont fait de la Sibérie Occidentale une des principales régions productrices de l'Union Soviétique. La rapide croissance de la production pétrolière malgré les conditions climatiques sévères de cette région est le résultat de l'emploi de conceptions scientifiques et techniques avancées pour la mise en valeur des gisements. La communication décrit les principales solutions nouvelles qui ont permis de résoudre des problèmes techniques de forage et de développement- des gisements. On a porté une attention toute particulière aux procédés de pose accélérée des grands oléoducs atteignant 2000 km de long et 50 pouces de diamètre. 1.
The thirties saw the beginning of the search for oil in Western Siberia. As a result of this work the total positive estimation of the prospects of gas and oil reserves of Western Siberia had been summed up by the year 1941. In 1953 near the settlement of Berezovo the first gas bearing layer was discovered and in 1960 in the lower Urals on the Konda River the first gusher spouted. Later on here was discovered an area bearing com- paratively moderate resources of light oil. In 1961 after the Meghionsky and Ust-Balyksky oil fields had been discovered the total volume of explora- tion work was transferred to the central part of the plain in the region of the latitudinal flow of the Ob River. Successive discoveries of Zapadno-Surgutsky, Loko- sovsky and Sovietsky oil fields in 1962 and 1963 finally proved the high efficiency of the region. In 1963 the government adopted a speci
HYDROCARBON OCCURRENCES FROM JOIDES DEEP SEA DRILLING PROJECT Abstract While most DSDP cores contain traces of liquid hydrocarbons deposited with the sedinients, and some- times large quantities of microbially produced methane gas, much of it probably as solid hydrate, a few cores contain hydrocarbons that apparently migrated into them. One enrichment was found in the cap rock of a salt dome in the deep Gulf of Mexico. A smaller bitumen enrichment was found on the Shatsky Rise in the western Pacific Ocean. Migrating gas- and gasoline- range hydrocarbons were detected in cores from the Balearic Basin and the Tasman Sea. Résumé Alors que la plupart des carottes du projet "JOIDES" contiennent des traces d'hydrocarbures liquides déposés avec les sédiments, ainsi que parfois de grandes quantités de gaz méthane d'origine micro- bienne, probablement en grande partie sous forme d'hydrate solide, quelques carottes renferment des hydrocarbures qui y ont apparemment migré. Un tel enrichissement a été observé dans le "cap rock" d'un dôme de sel dans la partie profonde du Golfe du Mexique. Un enrichissement en bitumes d'importance plus réduite a été signalé dans le Shatsky Rise, situé dans la partie occidentale de l'Océan Pacifique. Des gaz et des hydrocarbures du type essence naturelle provenant de migrations ont aussi été détectés dans des carottes du Bassin des Baléares et de la Mer de Tasmanie. 1.
A wide range of organic carbon contents, frequent occurrences of microbially produced methane gas, occasional occurrences of significant heavy hydro- carbons, and a few appearances of thermally produced light hydrocarbons have been noted in JOIDES Deep Sea Drilling Project (DSDP) cores. In the complex process of petroleum hydrocarbon genesis, the initial control is the deposition of remnants of living organisms together with the primal mineral matter of the host Sediments. Should the organic debris survive the journey to the sea floor, the hetero- geneous material undergoes several sequential changes -microbial alteration, chemical recombination and thermal degradation. These reactions form the spectrum of syngenetic organic entities-kerogen, nitrogen-sulphur-oxygen bitumens, and most hydro- carbons-that exist in most sedimentary rocks. This alteration process produces the compounds that migrate from source to reservoir and form petroleum deposits. by RICHARD D. McIVER, Exxon Production Research Company, Houston, Texas, U.S.A. In order to determine the amount and nature of organic materials in deep-sea Sediments and to attempt to trace the early stages of organic diagenesis, periodic samples are taken by DSDP scientists for organic geochemical analyses. Organic carbon is most frequently determined; this, on samples as received by the core repositories. Additionally, some cores are frozen, immediately after recovery, for studies of compounds that might otherwise be lost or degraded during s
DEEP WATER ENGINEERING IN THE NORTH SEA. PARTICULAR REFERENCE TO FORTIES FIELD PART I-DRILLING AND PRODUCTION PLATFORMS WITH Abstract The paper will identify the problems associated with the design, construction and installation of steel struc- tures for deep water and describe how they have been resolved in the development of the four platforms for the BP Forties field in the North Sea. A general description of the platforms will be given and particular areas of interest will be highlighted and suggestions given for improvements that can be made in the light of the Forties field experiences. In conclusion, the future of steel structures for the development of offshore fields in deep water will be discussed. Résumé Cette communication cherche à mettre en évidence les problèmes de conception, de construction et d'installation des structures métalliques installées en eau profonde et à montrer comment ils ont été résolus dans le cas des 4 plate-formes du gisement de Forties en Mer du Nord. On donne une description sommaire des plate- formes. On souligne certains domaines d'intérêt et on fait des suggestions pour l'amélioration des structures en tenant compte de I'expérience du gisement de Forties. En conclusion, on discute de l'avenir des structures métalliques dans le développement des gisements en mer. 1.
It is my intention in this paper to outline some of the major problems involved in the design, fabrication and installation of drilling and production platforms for the development of oil in deep water and to describe how these problems have been overcome in the development of the Forties Field platforms. The Forties Field is situated in the North Sea approximately 110 miles east of Aberdeen in water depths ranging from 350 ft to 420 ft. Four combined drilling and production platforms will be installed with identical deck arrangements, each capable of producing and pumping 125000 bd. The most westerly platform collects 20 in submarine lines from the other three platforms and manifolds into a 32 in line to shore. The jackets for the platforms are being constructed in dry docks at Graythorp, Middlesborough, by Laing Offshore, and at Nigg Bay, Scotland, by Highlands Fabricators. Separate flotation tanks are used to transport each by R. C. WALKER, British Petroleum Company, London, Great Britain of the jackets to site in a horizontal attitude and to rotate to the vertical by controlled flooding. The flotation tanks are being reused for the second pair of jackets. At the time of writing, two jackets have been successfully installed at location, one is completely piled with two major deck section modules in place and the other platform has sufficient piling to make it safe for the winter. Work is continuing on both platforms. The successful installation of two such platforms in the latter part of the summer is considered to be a tremendous achievement and indicates the value of the extensive planning t
PANEL DISCUSSION MANUFACTURE OF ETHYLENE AND HIGHER OLEFINS Chairman: A. MATSUYAMA (JAPAN) Vice-chairmen: J. F. MATHIS (U.S.A.) Scientific Secretary: M. YABUNE (JAPAN) RAFAEL A. ANELLO (ARGENTINA) Mr MATSUYAMA, the Chairman, briefly referred to the growth of the petrochemical industry and the pro- gress of associated sciences and technology in the past. He also explained the reasons why studies on the use of heavy petroleum fractions as the raw material for olefins are needed by referring to the present situation and future outlook for petrochemical feedstocks. The Chairman also covered the past technological developments in the fields of heavy oil cracking, feed pretreating and a-olefin production. After the Chairman's comments, the first panel member, Mr R. B. GREENE, presented his paper. He reported that a steam cracking plant designed to feed vacuum gas oil boiling in the range of 370-535°C has been operating since 1967 at Port Jérôme, France. Mr GREENE emphasised that coke deposited inside the radiant coils has been successfully removed with an onstream decoking technique, greatly extending run lengths. Mr A. JOHN GAMBRO presented his paper on the technology and economics of olefin plants with naphtha/gas oil feedstock flexibility in the plant design. He pointed out that such flexibility is desirable in the face of an uncertain future feedstocks situation. Professor D. KUN11 reported the results of an experimental study of crude and vacuum residue cracking using fluidised beds of coke particles. He stated that the new process will be economically superior to a conventional naphtha cracking process if a reasonable difference exists between naphtha and crude or vacuum bottoms prices. Professor S. NOWAK reported the experimental results of the cracking of heavy hydrocarbon feed- stocks which had previously been hydrotreated. He discussed the influence of chemical composition of 16 feedstocks on the product yield pattern from thermal cracking and concluded that hydrotreating of feed- stocks is an effective way to increase yield of ethylene and liquid cracked products including BTX. Another theme of Panel Discussion 19 was the production of higher a-olefins by thermal cracking of paraffin-base feeds. In this area, Dr A. N. RUMYANTSEV reported the kinetics and mechanism of thermal decomposition of high molecular weight n-alkanes and a-alkanes based on a comparison of experimental data and theoretical studies. He men- tioned that the mechanism of thermal decomposition of n-dodecane can best be explained by a modification of the Rice-Kosiakoff theory which included both radical chain and molecular processes. After the presentation by the five authors, Mr MATSUYAMA, the Chairman, briefly summarised each paper presented. He then urged the audience to turn in discussion slips for thediscussions that followed. Fifty-five questions and comments were submitted to the Chairman, and during the session twenty-six of them were taken up for discus