Solids recovery

Total Solids Recovery In clarification, the clarity of the effluent is measured indirectly by the total sohds recovered in the cake as... 

The solids recovery in the cake can be inferred from measurements using Eq. (18-90). It is shown as a function of G-seconds for different feed solids concentration in Fig. 18-141 see also theoiy discussed below. 

A thickener handles 80,000 gpd of sludge, increasing the solids content from 2.0 to 8.0 wt.% with 85% solids recovery. Determine the quantity of thickened sludge generated per day. 

Microbial cell recovery is carried out in a continuous disc-stack centrifuge. The centrifuge is operated at 5000 rpm for separation of baker s yeast. At a feed rate of 601/min, 50% of the cells are recovered. At constant speed, solid recovery is inversely proportional to flow rate. 

Pharmaceutical Removal of suspended matter is a frequent application for MF. Processes may be either clarification, in which the main product is a clarified liquid, or solids recovery. Separating cells or their fragments from broth is the most common application. Clarification of the broth in preparation for product recovery is the usual objective, but the primary goal may be recovery of cells. Cross-flow microfiltration competes w l with centrifugation, conventional filtration by rotary vacuum filter or filter press and decantation. MF delivers a cleaner permeate, an uncontaminated, concentrated cell product... 

The collection efficiencies shown in column 4 of the table were read from Figure 10.45a at the scaled particle size, column 3. The overall collection efficiency satisfies the specified solids recovery. The proposed design with dimension in the proportions given in Figure 10.44a is shown in Figure 10.48. 

This process, according to the manufacturer,54 has been developed in such a way that space requirements are kept to a minimum. A BIOPAQ IC reactor is used as the initial step in the treatment process. The name of this anaerobic reactor is derived from the gas-lift driven internal circulation that is generated within a tall, cylindrical vessel. These reactors have been operational in the paper industry since 1996. The second step in the purification process is a mechanically mixed and aerated tank. The aerating injectors can be cleaned in a simple way without the need to empty the aeration tank. Potential scaling materials are combined into removable fine particles. At the same time, the materials that may cause an odor nuisance are oxidized into odorless components. The process can be completed by a third and a fourth step. The third step focuses on suspended solids recovery and removal. The fourth step is an additional water-softening step with lamella separation and continuous sand filters in order to produce fresh water substitute. The benefits claimed by the manufacturer are as follows54 ... 

In fast-fluidized beds, which use extremely small catalyst particles, the flow of particles and fluid is cocurrent, and nearly PF, leading to high conversion and selectivity. However, severe erosion of equipment is common, and thus, the design of the solids recovery and recirculation system is important. 

S.B. Hawthorne, C.B. Grabanski, E. Martin and D.J. Miller, Comparison of Soxhlet extraction, pressurized liquid extraction, supercritical fluid extraction and subcritical water extraction for environmental solids recovery, selectivity and effects on sample matrix. J. Chromatogr.A 892 (2000) 421 133. 

Thus, solids recovery is defined as solids underflow... 

In fines removal, both the cut size and the grade efficiency are difficult to assess because of the limited accuracy of the sieve analysis technique and the problems Involved in the determination of the solids concentration in the overflow. For a. 65 m cyclone, whilst using a 20 mm vortexfinder diameter, an apex diameter of 16 mm and a feed flow of 1.6 1/s, solids recovery is over 99 % This recovery corresponds to a cut size between 50 - 100 pm. Typical distributions of size by weight, for the feed flow as well as the overflow are shown in Figure 5 Results are summarised in Table 2. 

Perforated basket Good dewatering, easy to clean, washing of cake possible Limited sohds capacity, solids recovery laborious, low centrifugal force, discontinuous... 

Multichamber bowl Increase in sohds capacity, no loss of efficiency up to complete filling of chambers Solid recovery laborious, discontinuous operation... 

These parts are used in fluidized beds for various purposes. For example, gas distributors and various types of baffles are installed to decrease the size of the bubbles. Moreover, draft tubes are used to enhance gas or solid circulation. Other devices such as horizontal baffles limit circulation and backmixing of solids and gas. Horizontal or vertical tubes are used for heat management. Devices used to control or improve fluidization behavior, to improve fluidization of cohesive particles or to achieve solids recovery are within the various internals met in fluidized bed reactors (Kelkar and Ng, 2002). Immersed tubes in small diameter beds may lead to slugging. Furthermore, attrition of particle breakage may change the size distribution and possibly change the fluidization behavior. 

Crystallizer Solid recovery from supersaturated solution Liquid-solid Atmospheric pressure, — 10-100°C... 

Two experiments (RSI, RS2) were performed with DC-II and Swedish wheat straw with particle size in the range of 1 to 2 mm. During these experiments the solids recovery system (cyclone and impinger, Figure 1) did not perform satisfoctorily with the very fragile straw char. The char, exposed to the very harsh envirorunent (fast moving sand particles) of the CFB reactor and atritted to very fine particles, almost submicTon powder, could not be collected by conventional solids recovery systems. Consequently, the char was either adhered with the liquids heavy fraction to the STHE inner tubes or readilly accumulated in the liquid recovery system. 

The reactor operability is easily sustained once steady-state operation is reached. The woody feedstocks produced much less fine char than straw, and the gas entrained solids were more efficiently recovered fay the solids recovery equipment. 

A significant problem remains the relatively high solids (char) content in the pyrolysis liquids, due to the fiagmentation of char and wood fines in the harsh environment which are subsequently entrained in the gaseous stream, an inherent characteristic encountered in all CFB reactor systems, (ineffective solids recovery system). 

Additional actions should be taken in order to achieve reliable performance of the scrubber under any conditions. A more efficient solids recovery system is essential to be incorporated in the plant. Scale-up at pilot (aji rox. 100 kg/h) or demo-scale (approx. 1000 kg/h) should also be considered. 

By objective. The process goal of filtration may be dry solids (the cake is the product of value), clarified liquid (the filtrate is the product of value), or both. Good solids recovery is best obtained by cake filtration, while clarification of the liquid is accomplished by either depth or cake filtration. 

From material balance, the particle size distribution of the feed and centrate, as well as the total solids recovery, determine the yield. 

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