Collection cyclone condenser

A venturi scrubber is a venturi-shaped air passage with water introduced just ahead of or into the venturi throat. The liquid-gas contact is at a maximum in the venturi throat. The relative velocity between gas and liquid aerosol droplets is high, with the gas velocities in the range of 50-100 m/s. The particles are conditioned in the throat, and condensation is the important collection mechanism. After the particles in the gas have been deposited on droplets, a comparatively simple device such as a cyclone collector can be used to collect the wetted dust. 

In a fluidized bed reactor, entrained particles leaving in a dilute phase stream are conventionally and desirably either partially or wholly condensed into a bulk stream and returned to the bed via a centrifugally driven cyclone system. At equilibrium, or when steady state operation is attained, any particle loss rate from the cyclones, as well as the remaining bed particle size distribution, are functions of (a) the rate of any particle attrition within the system and (b) the smallest particle size that the cyclone system was designed to completely collect (i.e., with 100% efficiency), or conversely the largest size which the system cannot recover. These two functions result in an interdependency between loss rate and bed particle size distribution, eventually leading to an equilibrium state (Zenz Smith, 1972 Zenz, 1981 Zenz Kelleher, 1980). 

In these systems, the total collection efficiencies of the dry product are 85 per cent for the drying vessel, 90 per cent for the cyclone collector and 98 per cent for the scrubber-condenser. The net efficiency of the system may be as high as 99.97 per cent if the scrubber effluent is considered as product. All the runs are based on 1.25 kg/s product and 0.75 kg/s evaporation at an elevation of 300 m above sea level. The total air flow is measured at the outlet before the stream is split into the recycle and bleed portions and, for such flows, the design of suitable fans is outlined by Jorgensen164 . The calculations outlined here may be confirmed by the use of psychometric charts, and this procedure has been considered in some detail by Cook and Demount165. ... 

The emission measurements during this testing included N0X, smoke, particulate and PNA. N0X was determined by a non-disper-sive infrared analyzer, and smoke by the Bacharach test. Both the particulates and PNA were sampled by a source assessment sampling system (SASS). The SASS system isokinetically samples a fraction of the stack gas and traps particulates in a series of cyclones, which classify the particulate by size. Final filtration is through a fiberglass filter mounted in an oven heated to 200°C to prevent condensation of acids. In this program, the cyclones were not used, since previous work (3) had shown the particulate from coal-derived fuel oils to be small, with an average diameter on the order of 0.4 /um. The PNA which is not deposited on the particulate is collected on XAD-2 resin after the gas has been cooled to 15-20°C. PNA analyses were carried out on a combined extract from the particulate, XAD-2 resin, other condensates in the system, and the solvent rinses used to clean the SASS system. 

The reactor is constructed with a cylindrical colnmn and an expanded freeboard. The distributor is a perforated plate. An inert gas matrix composed primary of crystal sand, is used as the bed material. The blower supplies the inert gas for flnidization or the amount of air for partial combustion. A cyclone is used to collect fine particles. Sembbers serve to quench the off-gases and remove condensables that were withdrawn from reactors. 

Dry cyclones are the primary collection equipment used to capture the detergent dust in the spray dryer exhaust and recycle it back to the crutcher. The dry cyclones can remove up to 90 percent by weight of the detergent product fines from the exhaust air. Fabric filters have been used after cyclones but have limited applicability, especially on efficient spray dryers, because of condensing water and organic aerosols binding the fabric filters [4, 21]. 

The gas stream leaving the cyclone contains hot air, the excess ammonia, water evaporated from the nitric acid solution in the reactor and from the collected liquid in the cyclone, and 3% of the ammonium nitrate in the reactor effluent. The stream leaves the separator at 233°C, passes through the air preheater, and enters a partial condenser where some of the water and ammonia and essentially all of the nitrate are condensed. The equilibrium relationship between the compositions of the vapor and liquid streams leaving this unit may be expressed in the form... 

The product gas passed through a cyclone that captured fine catalyst particles and any char generated in the reactor, then two heat exchangers to remove excess steam. The condensate was collected in a vessel whose weight was continuously monitored. The outlet gas flow rate was measured by a mass flow meter and by a dry test meter. The concentrations of CO2, CO, and CH in the reforming gas composition were monitored by a non-dispersive infra-red analyzer (NDIR Model 300 from California Analytical... 

The third atmospheric technique analyses the residual liquid and/or condensate hydrocarbon traces on aerosols carried into the atmosphere by thermals (Barringer, 1981). The aerosols are created by gas bubbles which exsolve into the atmosphere from the sea in areas where microseeps create gas bubbles which reach the sea surface. The aerosols are concentrated from large volumes of air and collected by an airborne cyclone sampler carried aboard an aircraft which is flown at 30 m (100 feet) above the sea surface. Hydrocarbons adsorbed on the aerosols are measured by a flame ionisation detector which yields a total hydrocarbon signal. This system is claimed to produce... 

Analyses showed the primary solid product, collected in the lift exit cyclone, was indeed sodium carbonate, as expected. The evaporated liquid waste was condensed and analyzed following processing and determined to be nonhazardous by Federal and State standards. Inspection of spheres removed from the process following shutdown showed no signs of sticking, tacking or agglomeration. 

Since higher molecular weight organic compounds were found after the cyclone than further down the process stream the condenser samples and a filter sample from after the cyclone were studied further. Because all the gas chromatograms of condenser samples indicated the presence of components with a wide range of volatility, a portion of the dichloromethane sample collected at 0 C was fractionated by the Sephadex LH-20 column. The mass distribution of this condenser sample and its subfractions are given in Table IV. 

The experimental determination of the feed consumed, the char yield, and the noncondensible gas yields are relatively straightforward. However, the primary vapor and water yields have proven difficult to measure directly due to the formation of aerosols. These aerosols escape high-pressure sprays, cyclonic separators, and impingement or inertial collection techniques. The use of condensible steam as the carrier gas makes the water yield very... 

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