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In conveying pulverized coal pneumatically to a blast furnace using compressed nitrogen, it was observed that the conveying system would plug with passage of time due to coal deposition. A pilot test rig was designed and operated in order to probe whether specific types of bends are responsible for this process and to identify problematic bend types. The test rig was operated to closely mimic actual plant conditions. Three different bends: a long radius bend (LR bend with R / D =7.2) actually used in the plant, a short radius bend (SR bend with R / D =2.4) and a blinded T bend both fabricated from glass were tested in a horizontal to vertical orientation. Among the bend types tested, the LR bend was found to produce maximum buildup. In a test conducted over 90 min, buildup was observed after around 20 min at the first point where the direction of flow changes, ultimately leading to blockage of approximately 50% pipe cross-sectional area at the end of the run. The blinded T bend was found to be self-cleaning, with negligible deposits even after 30 min of continuous operation. With the SR bend, some fine deposits were observed on the outer edge of the bend where considerable sliding of particles occurs. A solids flow-metering device based on pressure drop measurements in dilute phase conveying systems was developed earlier. This meter is based on the linear relationship between specific pressure drop ratio between suspension and single-phase conveying gas flow and the suspension loading. This meter was tested for metering the pulverized coal feed and found to give satisfactory metering performance over the range of conditions tested.

The measurement of flow rates of solids in gas–solid flows is a challenging task. Fibrous materials are known to change in character as they flow and, as such, can compound the difficulty of measurement of such flow rates over that of powders and granular materials in the transport condition. The principle of measuring the pressure loss experienced by a gas–solid flow in a straight section of piping was used here to test a metering device for fibrous solid flow which has been shown to work for a wide range of powders and granular materials in our laboratories. The flow rates obtained for the fibrous material had a high degree of reproducibility suggesting the possibility of widespread industrial application of the pressure drop flow-metering device.

Two enzymes (subtilisin and thermolysin) have been modified with a polyethylene glycol (PEG, MW 3400) having an acrylate group at one terminus and an active ester at the other terminus and then incorporated into polyacrylates during free-radical initiated polymerization in a variety of organic solvents. Despite the high activity of the radical intermediates, both enzymes remain active and stable after incorporation. The activity and stability of the resulting biopolymer produced by subtilisin have been compared, in both aqueous and organic media, to those for the native, PEG-modified, and traditionally-immobilized subtilisins. In aqueous solution, the biopolymer had a reduced Km and k,, relative to the native subtilisin, but the specificity constant (kcatlKm) was only reduced to oneninth by incorporation into the polymer. In a flow-cell reactor, the biopolymer achieved the longest half-life (> 100 days) relative to the other forms of the enzyme. The enzyme’s tolerance toward both heat and a miscible organic solvent was also enhanced by incorporation into the polymer.

An exergy analysis of a power system identifies the location, type, and magnitude of losses of the potential to do work, while a pinch analysis examines a heat exchange network efficiency. A complete exergetic analysis of Kalina cycle System 19, an advanced binary fluid (ammonia-water working fluid) power cycle, is presented along with a combined pinch/exergy analysis of the Kalina cycle heat exchanger/furnace/cooling utility network. The Kalina cycle System 19 has a net thermal efficiency (net work/furnace duty) of 43% (HHV), a furnace exergetic efficiency of 77.4%, and an exergetic plant efficiency (net work/exergy of flue gas) of 61.6%. Most of the exergy losses (21.5%) occur in the furnace; 9.6% of the exergy is lost in pumps, turbines, throttles, mixers, and the stack gas; and 7.3% of the exergy loss occurs in heat exchanger/cooling utility network. The System 19 total exergy loss in all heat exchange equipment is only 7.2% greater than its minimum value. Thus, the analysis indicates that the Kalina cycle System 19 is efficiently designed.