Supplementary combustion

Nitrogen is carried through the combustion unchanged and forms a large part of the carrying gas for any unused oxygen. Supplementary combustion (or reheat) can then take place if more fuel is supplied to the products of primary combustion. 

Ballestra do not preheat the furnace but electrically ignite the sulphur flow to the fiimace. It is important to follow exactly the recommended operating procedure and particularly to ensure that the electric elements are (kawing the specified current and the supplementary combustion air is at the correct pressure and flowrate (small rotameter). On start-up die temperature of the fiimace rises to the auto-ignition temperature of sulphur in approximately 3-5 minutes at which point the ignition procedure can be terminated. 

A commercial combustion turbine with the provision to inject, at any point upstream of the combustor, the externally supplied humidified and preheated supplementary compressed air. Engineering and mechanical aspects of the air injection for the compressed air injection plant concepts are similar to the steam injection for the power augmentation, which has accumulated significant operating experience. 

The exhaust gases from a gas turbine contain substantial amounts of excess air, since the main combustion process has to be diluted to reduce the combustion temperature to well below that which could be obtained in stoichiometric combustion, because of the metallurgical limits on the gas turbine operating temperature. This excess air enables supplementary firing of the exhaust to take place and higher steam temperatures may then be obtained in the HRSG. 

Fig. 9.2 shows how a simple open circuit gas turbine can be used as a cogeneration plant (a) with a waste heat recuperator (WHR) and (b) with a waste heat boiler (WHB). Since the products from combustion have excess air, supplementary fuel may be burnt downstream of the turbine in the second case. In these illustrations, the overall efficiency of the gas turbine is taken to be quite low ((tjo)cg = ccJf ca 0.25), where the subscript CG indicates that the gas turbine is used as a recuperative cogeneration plant. 

The use of plastics as an energy source was demonstrated on a commercial scale at ICl Materials plastics manufacturing site in Dumfries, UK. This paper covers the preparation and use of pre- and post-consumer plastics as supplementary fuels in a circulating fluidised bed boiler specially designed for co-combustion with coal. Full emissions data on the 15% mixtures of individual plastics with coal are given, together with calculations of thermal efficiencies. Measurements by an independent body (British Coal Research Establishment) confirmed that the co-combustion of coal and plastic reduces some emissions compared with coal alone. Thermal efficiencies of around 80% were achieved and this heat was used effectively during the production of plastics. 7 refs. 

This book is a supplementary source of knowledge on combustion, to facilitate the understanding of fundamental processes occurring in flames during their formation, propagation, and extinction. The characteristic feature of the book lies in the presentation of selected types of flame behavior under different initial and boundary conditions. The most important processes controlling combustion are highlighted, elucidated, and clearly illustrated. 

Overall, EGR and combustion/injection systems constitute the key factors to comply with the EuroIV standards (applied in January, 2005). The EuroIV step exhibits EuroIII NO and soot particles limits divided by 2. Besides, vehicle s weight is always increasing due to the introduction of new safety systems and equipment. Therefore, pollutants emissions increase and a supplementary effort to reach the normative threshold is to be made. To comply with this target, some evolutions have been introduced, as for example multi-injection or water-cooling of the EGR system. The NO,/particle compromise adjustment remains possible for most of the applications without any after-treatment system like the Diesel particle filter (DPF). 

There are three major types of processes for direct combustion of waste biomass water-wall incineration, supplementary fuel co-firing with coal or oil, and fluidized bed combustion. 

Recuperation. A recuperator is used to exchange heat between the turbine exhaust and compressor exit air. As in the case for the heat of compression, fuel cell AT is managed via the compressor air mass flow. In the simulations, the recuperator was not able to provide all of the heat necessary to preheat the cathode flow to the desired temperature. Methods for adding additional heat to the system are supplementary fuel added to a combustor before the fuel cell or after, or cathode recycle can also be used to make up the difference. Here, supplementary fuel was added after the fuel cell, to the post-combustion system. 

The project at Plant Sweatt was organized with Southern Company Services as EPRI s prime contractor responsible for project management, project direction and subcontractor performance. Subcontracted to Southern Company Services were Babcock Wilcox (B W) and KVB. B W provided technical consultation and boiler performance evaluations, KVB provided combustion gas emission characterizations and supplementary technical consultation. 

Yet another possibility relies upon the remarkably high capacity of the electrical double layer. The so-called condenser batteries (Chapter 13) would provide a supplementary energy supply analogous to that of superchargers on internal combustion vehicles. Extra electricity storage capacity would be available with acceptable energy density for startup, acceleration, and passing (Conway, 1998). 

We have developed several new measurement techniques ideally suited to such conditions. The first of these techniques is a High Pressure Sampling Mass Spectrometric method for the spatial and temporal analysis of flames containing inorganic additives (6, 7). The second method, known as Transpiration Mass Spectrometry (TMS) (8), allows for the analysis of bulk heterogeneous systems over a wide range of temperature, pressure and controlled gas composition. In addition, the now classical technique of Knudsen Effusion Mass Spectrometry (KMS) has been modified to allow external control of ambient gases in the reaction cell (9). Supplementary to these methods are the application, in our laboratory, of classical and novel optical spectroscopic methods for in situ measurement of temperature, flow and certain simple species concentration profiles (7). In combination, these measurement tools allow for a detailed fundamental examination of the vaporization and transport mechanisms of coal mineral components in a coal conversion or combustion environment. 

Reid W. T. (1981) Coal ash-its effects on combustion systems. In Chemistry of Coal Utilization, 2nd Supplementary Volume (ed. M. A. Elliot). Wiley, pp. 1389-1445. 

The Tobata pilot plant has been conducting experiments since 1974, The gas processing system was of the inflammable gas recovery type originally, but later modified to permit operation on the direct combustion principle, also. At present, the system is operated mostly using the latter method. Using this pilot plant, basic, comparative studies have been made on the furnace profile, effects of the properties of wastes and the oxygen concentration in the blast, the need for supplementary fuel, and how to process the product gas. 

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