Calorific values plant

Another common impurity of natural gas is nitrogen. Since nitrogen has essentially no calorific value, it lowers the heating value of gas, Gas purchasers may set a minimum limit of heating value (normally approximately 9.50 Biu/scl). In some cases it may be necessary to remove the nitrogen to satisfy this requirement. This is done in very low temperaliire plants or with permeable membranes. These proces [Pg.4]

Condensing boilers are now available for both gas- and oil-fired plant, the advantage of these being that the flue gases are further cooled down to below 100°C so that the latent heat available in the flue gas water vapor is recovered. The condensate has to be removed and the boiler capital cost is higher than for conventional plant. However, the boiler plant efficiency is increased to the order of 90 per cent, based upon the fuel gross calorific value. Where the flue gas exit temperatures are in excess of 200° C a further economy can be obtained by the provision of a spray recuperator in the case of gas and flue gas economizers for oil and coal. 

For SNG manufacture, it is necessary to reduce the residual hydrogen to a minimum in order to achieve a high calorific value. This is best realized if the synthesis gas, instead of having a stoichiometric composition, contains a surplus of C02 which can be utilized to reduce the H2 content by the C02 methanation reaction to less than 1% according to equilibrium conditions. The surplus C02 must be removed at the end of the process sequence. It is, of course, also possible to operate a methanation plant with synthesis gas of stoichiometric composition then there is no need for a final C02 removal system. The residual H2 content will be higher, and therefore the heating value will be lower (cf. the two long term runs in Table II). 

Other attempts to improve nitrodiglycol powders were based on the introduction of substances such as penthrite (German Nipolit Pulver) and cyclonite. In both cases a powder with a high calorific value was obtained. The manufacture of these powders never went beyond the pilot plant scale ... 

A boiler plant raises 5.2 kg/s of steam at 1825 kN/m2 pressure, using coal of calorific value 27.2 MJ/kg. If the boiler efficiency is 75%, how much coal is consumed per day If the steam is used to generate electricity, what is the power generation in kilowatts, assuming a 20% conversion efficiency of the turbines and generators ... 

Eor (1), MSWIs, the maximum bonus is limited by the calorific value of the plastics waste (about 40 MJ/kg). Eurthermore, the energy recovery is relatively low due to technical limitations in comparison to normal power plants. Normally, at best some 20% electrical energy is recovered (or some 50%-70% calculated as primary energy). 

Powder by Pike (Ref It was one of the "G Pulvem (DEGDN propints), which contd NC DEGDN, 1.5% K nitrate and 3% hydrocellulose. Its calorific value was 710—730 kcal/kg. It was introduced in 1944 as the "Service proplnt for all ammunition in order id minimize the differences in ballistics previously obtd when propints of the same formulations were manufd at different plants. The incorporation of K nitrate and of hydro cellulose was claimed to give much more uniform interplant ballistics of Einheitspulver... 

The flow diagram for a rich gas plant producing gas with a calorific value of 710 Biu/slandard cubic foot is shown in Fig. 1. The product is used to enrich lean gas from an IC1 (Imperial Chemical Industries) naphtha reformer which has a calorific value of about 320 Btu/standard cubic foot to the town gas standard of 500 Btu/standard cubic foot (56 Calories/cubic meter). Typical gas analyses arc given in Table 1. 

The calorific value of the product from hydrogasification is lower than that from single methanation, particularly with high carbon/hydrogen feedstocks because of the additional steam required. However, by adding a final metlianator. the calorific value can be increased to that obtained from double methanation, again with increased capital cost and reduced efficiency. This process (Fig. 2) is used in the first operational SNG plant in the United States at Harrison, N.J. Typical gas analyses are given in Table 4. 

The calorific value is normally the basic item specified in contracts for coal to be used in steam plants. It is the most important value determined for coal that is to be used for heating purposes. In coal contracts, the calorific value is usually specified on the as-received basis. Any error in the moisture value is reflected in the as-received calorific value. 

The main plant output from fuel chemical exergy would be a function of the amount of fuel isothermally oxidised in the fuel cell, with a minority contribution from the calorific value of the fuel burnt in the... 

An oil of low flash point in the range 14-18°C, and of 41-43 MJ Kg gross calorific value has been obtained in batch pyrolysis [36] of automobile tyre waste. In a pilot plant with semi-continuous feeding [37] the liquid yield of tyre waste decreased seriously with increasing temperature, and it was always lower in an atmosphere containing oxygen that in nitrogen. 

In short it can be stated that the pyrolysis of 100 kg of municipal refuse, predried to a water content of 18 % by weight and having a calorific value of 8370 kJ/kg and to which 77.6 kg of air have been added, produces in the two-stage plant an average of... 

Basis for Plant Design. The composition of municipal refuse is assumed as shown in Table III. The municipal refuse has the lower calorific value of ca. 1,500 Kcal/Kg. Plant size of 600 T/D is assumed. The capital investment costs, utilities, etc. were calculated using contacts with equipment vendors. Cost for repairs are assumed to be two percent of the plant construction cost per year. Unit costs of utilities and unit prices of recovered energy and material are assumed, based on the actual prices in 1979. Ash and other residues disposal cost is assumed to be 2,450 Yen/T, taking note of the representative cost data of large cities in Japan, The grant available to a municipality is assumed to pay up to fifty percent of the capital investment. The remaining investment cost must be amortized in fifteen years with the interest rate of six percent. 

The produced combustible gas of the demonstration plant has a different composition from that of the small pilot plant. The former includes more carbon monoxide and less carbon dioxide than the latter. The difference in gas composition between the two tests seems to come from the fact that in case of the larger reactor, supplied solid waste is heated up promptly and over-cracking is prevented. Because of the high carbon monoxide content, the calorific value of the demonstration plant is higher than that of the small reactors. Sampling of the combustible gas for... 

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