Effluent autoclave

To separate any ethylene from the LDPE in the autoclave effluent, the pressure is let down in successive vessels and the ethylene flashes off (vaporizes). It is recycled to the compressors. The LDPE in a molten (hot liquid) state is cooled, extruded, pelletized, dried, and bagged. 

The sodamide which is formed remains liquid (m.p. 210°) and does not prevent contact between the remaining sodium and the ammonia gas. The progress of the reaction is followed by passing the effluent gas through water which absorbs the ammonia and allows the hydrogen to pass if there is unabsorbed gas which forms an explosive mixture with air, the reaction is not yet complete. For the second step, the sodamide is introduced into a nickel or nickel-lined, trough-shaped autoclave along the bottom... 

The solvents which have been used to date represent two extremes (Table 1). One is a hydrogen enriched (9.67% H) SRC-1 recycle solvent (92-26-019) while the other is a hydrogen depleted (8.15% H) SRC-1 preheater effluent solvent (92-03-035). Reactions were performed in a 300 cc stainless steel batch autoclave which has been previously described in detail (1). The experimental procedure has also been described (2). Experiments in this paper were performed at 1400 psig of hydrogen at a solvent to coal ratio of three to one. 

Fig. 2 Continuous polymerization apparatus A, CO2 cylinder B, monomer C, initiator solution D, continuous syringe pumps E, syringe pumps FI, steady-state filter G, thermo-stated autoclave H, static mixer I, chiller/heater unit J, effluent cooler K, gas chromatograph VI, V2, four-way valves V4, three-way valves V5, V6, two-way valves V7, heated control valve [51]... 

The liquid effluent of the reactor is cooled in cooler E2 to 260"C. This is sufficiently low to stop any undesired reactions leading to degradation of the biocrude. In separator section S the two liquid phases, water and biocrude, are separated. Experiments in autoclaves have shown that at this tenperature the two liquid phases separate well and that their mutual solubility is sufficiently low to avoid excessive loss or contamination of the product. From the water stream from the separator the recycle water is routed to the recycle puiiq) and then to heater E3, The remainder is the stream water leaving the main section in Figure 3. 

The treatment of sewage effluents was studied by bubbling ozone through untreated or autoclaved sewage samples to which had been added tracer microorganisms, infectious bacterial spores, influenza virus, or the toxin produced by Clostridium hotulinum. 

The example is taken from a polymerization batch process and has also been referred to previously by Dahl et al. [1999] and Kosanovich et al. [1996], The dataset consists of 50 batches from which eight process variables are measured over approximately 120 time intervals. From this set of batches, two quality variables on the final product were also available. Both process and quality variables are listed in Table 10.7. The reactor in this chemical process (see Figure 10.26) converts the aqueous effluent from an upstream evaporator into a polymer product. The reactor consists of an autoclave and a cooling/heating system. It also has a vent to control the vapor pressure in the autoclave. The recipe specifies reactor and heat source pressure trajectories through five stages. 

This experiment was carried out in accord with an established procedure (5). Unbleached softwood kraft pulp (USKP) from Douglas fir was obtained from Pope and Talbot (Halsey, Oregon) and washed with deionized water until the effluent was neutral and colorless. USKP (8.0 g, oven-dried) was autoclaved at 121 °C for 40 min, cooled down at room temperature and then inoculated with 3 mL of P. cinnabarinus spore suspension (ca. 9 x lO spores/mL). The moisture content of the culture was adjusted to 80% and the culture was incubated statically at 30 °C. After a pre-determined incubation time, mycelia were carefully removed fiom pulp. Hie treated pulp was analyzed for kappa number. 

This process is designed to treat small quantities of sodium with an excess of water and to support the rapid raise of pressure due to the reaction. Sodium is placed in a vessel in the upper part of the autoclave. Inside air is swept out and the reactor is filled with a neutral gas. The bottom of the reactor is then filled up with water. Sodium is dropped into this water volume, and a violent sodium/water reaction is obtained. When the pressure is stabilized, reactor is decompressed and gas effluents are diluted after filtration and dehumidification. 

Consideration must be given to the likelihood of escape of the agent and the consequences of such an escape. Whether the effluent disposal system is a simple autoclave or large multi-vessel plant, certain principles must be... 

The choice of autoclave or dedicated plant. It is easy both to under- or over-estimate the required processing capacity when designing an effluent disposal facility. Over-estimation may lead to excess capital and perhaps running costs under-estimation may lead to process delays while effluent is treated, and increased risk of escape of agent. To err on the side of overestimation is the safe course, if capital costs allow. 

Small unit volumes of effluent (up to 50 litres) can be treated in a steam autoclave, provided that adequate measures are taken to transfer the material in a safe and contained manner to the autoclave chamber. A Class III cabinet line or contained suite in which the work is performed, and to which the autoclave chamber has direct access provides excellent containment security, but is not conducive to the processing of more than a few litres at a time. Transport of liquid in a leak-proof secondary container permits larger volumes to be handled, but consideration must be given to the logistical problems associated with the transport, especially if the autoclave is situated in a relatively remote location, or is inside another suite. If the autoclave has one door only, procedures must be adopted to ensure that contaminated and safe materials are not mixed. Double door autoclaves permit the uni-directional flow of waste out of the facility, and in the UK are recommended or mandatory for the higher categories of containment. " ... 

What provision is made for the containment of the (unsafe) effluent in the event of autoclave control failure , i.e. can the material be securely returned to the source and can the autoclave be made safe for maintenance/repairs to be undertaken ... 

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