Feeding vessels

The calcium cyanamide feed is weU mixed with the recycled slurry and filtrate ia a feed vessel. The calcium cyanamide is added at a rate to maintain a pH of 6.0—6.5 ia the cooling tank. The carbonation step can be conducted ia a turbiae absorber with a residence time of 1—2 min. After the carbonation step, the slurry is held at 30—40°C to complete the formation of calcium carbonate, after which the slurry is cooled and filtered. AH equipment for the process is preferably of stainless steel. The resulting solution is used directiy for conversion to dicyandiamide. 

Reactor contents inadvertently admitted to upstream feed vessel. Possibility of reaction in piping and vessel. 

Install surge pot between feed vessel and reactor to minimize effects of inadvertent mixing... 

Install emergency relief device (ERD) on feed vessel or feed line... 

Gas pressurized Monitor tank level and provide interlock for feed feed shut-off overpressurizes, alternate fluid delivery system (e.g., pump) centrifuge system when feed vessel delivery gas pressure to maximum safe empties working pressure of downstream system (e.g., pressure regulation) Restrict feed flow rate to be consistent with vent capacity Ensure adequate vent capacity for maximum possible gas flow ... 

Use minimum flow recirculation lines piped back to feed vessel... 

Nitrogen blow Provide level indicator in feed vessel with through into alarm/interlock drum from feed vessel during pressure transfer leading to loss of containment. AGA XK0775 CCPS G-3 CCPS G-15 CCPS G-22 CCPS G-23 CCPS G-29 FMEC 1997... 

Zufluss, m. flow, flux, afflux, influx, inflow (Tech.) feed reaoiirces (of a stream) tributary, -behalter, m. feed tank, feed vessel, -rohr, n. supply tube or pipe, feed pipe. 

Current Development. Following success of the prototype IPU a second more comprehensive facility was commissioned. This is capable of up to four pumps of mixed peristalitic or diaphragm types, each linked to specific feed vessels on individual balances. The whole is interfaced to an IBM AT computer (see Figure 7) which in addition to Intelligent liquid additions, has the capacity to absorb modules from the work on temperature control and stirring in a full multi-tasking computer-assisted system, as mentioned above. 

The entrance loss from the feed vessel is given by... 

In practice, it is sometimes possible to incorporate moving blades in the filter equipment so that the thickness of the cake is limited to the clearance between the filter medium and the blades. Filtrate then flows through the cake at an approximately constant rate and the solids are retained in suspension. Thus the solids concentration in the feed vessel increases until the particles are in permanent physical contact with one another. At this stage the boundary between the slurry and the cake becomes ill-defined, and a significant resistance to the flow of liquid develops within the slurry itself with a consequent reduction in the flowrate of filtrate. 

The concentration of solids in the slurry in the feed vessel to the filter at any time can be calculated by noting that the volumetric rate of feed of slurry must be equal to the rate at which filtrate leaves the vessel. For a rate of flow of filtrate of dV/dt out of the filter, the rate of flow of slurry into the vessel must also be dV/dr and the corresponding influx of solids is (1 — e0) dV/dt, where (1 — e0) is the volume fraction of solids in the feed slurry. At any time f, the volume of solids in the vessel is V(1 — ev), where V is its volume and (1 — ev) is the volume fraction of solids at that time. Thus a material balance on the solids gives ... 

The amount of olefin consumed was determined by the decrease of pressure with time, measured on the feed vessel, kept at constant temperature by water circulation, where the olefin was maintained in the gaseous state. 

The system design pressure is that of the weakest item of equipment which could be connected to the reactor during runaway. In this case it is the feed vessel with a design pressure of 5.5 barg. 10% accumulation is allowed during pressure relief for BS 5500. Thus,... 

Supercritical carbon dioxide is depressurized through the expansion valves into separator columns 4 and 5, where the product and the unreacted substrates are recovered. The substrates are collected in column 5 and recycled (added to the feed through the pipe connecting column 5 with the feed vessel). The gas phase is finally vented into the atmosphere after flow-rate measurement through a rotameter. The gas can be condensed and recycled on a pilot- or industrial scale. 

The substance which has to be micronized is filled into a thermostatted feed vessel (A) (Figure 9.8-6). The solution from (A) is transferred into the thermostatted autoclave (C) after evacuation. The compressible medium is supplied by a high-pressure pump (B). The pressure in the autoclave is increased to a certain value, and the high-pressure circulation pump (D), connected with the autoclave, is installed to increase the efficiency of dissolving of the solute by circulating the liquid phase. The gas-saturated mixture is rapidly depressurized through a nozzle. In the spray-tower the solvent is set free, and the formed solid particles of the substance under consideration (>10 pm) are collected in the vessel at the bottom. The temperature in the spray can be measured and recorded via two thermoelements. 

All the animation reactions are conducted in a 100-gal stainless steel reactor heated with 75 psi steam to the jacket. The reactor is fitted with an ammonia inlet, a vent tube for azeo-troping w from the system and a thermowell The TCTNB is first dissolved in toluene in a feed vessel and passed thru a 1.5 pm in-line filter during transfer to the reactor. The soln is then heated to 140° and the w azeotroped from the system. The ullage is then backfilled with ammonia and the temp brought to 150°. The... 

Voxels that represent the AIF must meet the following conditions (a) The maximum signal drop is larger, (b) the TTA is shorter, and (c) the rMTT is lower than that of normal brain tissue (Fig. 6.6). Furthermore only voxels in the vicinity of the feeding vessels are considered, whereas voxels within the feeding vessels suffer from pulsation artifacts and therefore cannot contribute to the calculation of AIF. 

Typical "plant equipment is shown in Fig. 3. The equipment racks are assembled and tested before being installed in hot cells. This rack, which served for some five years, has one high-pressure pump, a short "loading column, two long elution columns, and appropriate associated valves, feed vessels, product collection apparatus, and plumbing. Resin was periodically replaced by hydraulic transfer. 

The feedline is planned in a way that even high melting, high viscous or oxidation sensitive substances can be fed into the column. The feed vessel has a temperature controlled wall and bottom heating. It is equipped with an inert gas pipe to prevent the feedstock from oxidative reactions. A stirrer ensures a constant heat transfer from the walls to the feed bulk... 

The feed tank is mounted on the ceiling using chains and a weighing cell. Continuous weighing of the feed vessel stands for an exact mass balance not influenced by pulsation of the feed pump, volumetric or viscosity effects. To ensure that the connected feed pipes do not block with solidifying liquid they are equipped with an explosionproof electric heating wire which holds an adjustable temperature. 

Mass flow measurements are required for several control circuits and for balancing the experiments. For a maximum flexibility, gauges have been installed which measure the mass flow via the Coriolis-forces. The mass of the feed vessel is continuously measured by a weighing cell The integrated weight loss is used to control the frequency of the feed pump. 

Kinetics were determined using the laboratory pyrolysis unit with the melter/feed vessel temperature set at about 325°C and the pump temperature set at about 300°C. By varying the speed on the gear pump, residence times in the furnace were set. Residence times used ranged from 1 to 12 min, yielding a HDPE throughput of about 100 to 1200 g/h. 

Suppose that our gradostat consists of n vessels. Let Ejj be the constant (volumetric) flow rate from vessel j to i (i j), with the convention that Ejj = 0 for i = l,..., . Let Vj be the volume of fluid in the / th vessel, Dj the flow rate from a reservoir to vessel / (D, = 0 if no such reservoir exists), the concentration of substrate in the reservoir feeding vessel i (S/° = 0 if D, = 0), and Cj the flow rate from vessel i to an overflow vessel (C, = 0 if no such vessel exists). The notation diag(/3,) is used to denote a diagonal matrix whose diagonal elements are given by / , E is the matrix of flow rates Ejj. 

The flow system comprise the following flows Qj, Qa. Qb. —. Qz flows from feed vessels to reactors j, a, b,. .., Z. Qj, Q a, Q b, Qz flows leaving reactors j, a, b,. .., Z, outside. There are also interacting flows between the reactors, i.e. each reactor is feeding all the others. Finally, flows qj are from each reactor to the collector... 

The states of the system are the following concentrations and enthalpies (or temperatures) of the different species inside the various reactors a) The concentrations Cf,inj of species f at the peripheral feed vessels to reactor j in Fig.5-1 as well as the specific enthalpy hin,j (or Tjnj) of the fluid in the feed vessel to j b) The concentrations Cf,in,k of species f at the feed vessels to reactors k and the specific enthalpy hin.k (or Ti ,k) of the fluid in the feed vessels to k c) The concentrations Cfk of species f in reactors k as well as the specific enthalpies hk, h (or Tk, T ), respectively, of the fluid in reactors k and in collector Thus, the state space SS for the system will read ... 

Cf,in j is the concentration of species f at the inlet stream Qj flowing from a feed vessel into reactor j Cfkand Cg are, respectively, the concentrations of species f in reactors k and j. C fj is the concentration of f in the stream Q j leaving reactor... 

Cf,in,i is the concentration of species f in the stream Qi flowing from the feed vessel into reactor i, Cfj is the concentration of species f in reactor j, Cfk is the concentration of species f in reactor k and Cf, is the concentration of species f in reactor i. C fi is the concentration of species f in stream Q i leaving reactor i. kfp.i piACfp J = i Cfp jVj is the niass transfer rate of species f into (or from)... 

The definitions of the various quantities appearing in the above equation and those below are similar to those which follow Eq.(5-19) and (5-21a) whereas) is replaced by i. Introducing similar transformations to those in Eq.(5-20), as well as hj = Qjp and hj = QiPi j, where Q i is the volumetric flow rate leaving reactor i and Qj is the flow rate of the fluid from a feed vessel into reactor i p l is the density of the fluid leaving reactor i andpin,i is the density of the fluid from the feed vessel. 

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