Process flow diagrams, construction

The use of process flow diagrams and material balances are worthwhile methods to quantify losses or emissions and provide essential data to estimate the size and cost of additional equipment, other data to evaluate economic performance, and a basefine for tracking the progress of minimization efforts (Ref. 3). Material balances should be apphed to individual waste streams or processes and then utilized to construct an overall balance for the facility. Details on these calculations are available in the literature (Ref. 8). In addition, an introduction to this subject is provided in the next section. 

Process flow diagrams are more complex and show all main flow streams including valves to enhance the understanding of the process as well as pressures and temperatures on all feed and product lines within all major vessels and in and out of headers and heat exchangers, and points of pressure and temperature control. Also, information on construction materials, pump capacities and pressure heads, compressor horsepower, and vessel design pressures and temperatures are shown when necessary for clarity. In addition, process flow diagrams usually show major components of control loops along with key utilities. 

Prepare a process flow diagram, showing the major items of equipment in the correct elevation, with an indication of their internal construction. Show all major pipe lines and give a schematic outline of the probable instrumentation of the reactor and its subsidiaries. 

Prepare a process flow diagram, up to but not including the drier, showing all the major items of equipment, with indications of the type of internal construction, as... 

Before the HAZOP study is started, detailed information on the process must be available. This includes up-to-date process flow diagrams (PFDs), process and instrumentation diagrams (P IDs), detailed equipment specifications, materials of construction, and mass and energy balances. 

Based on these disadvantages Veba Oel Technologies constructed a new pilot plant for the pyrolysis of refinery and hydrogenation residues using indirectly heated rotary kilns (Figure 19.2 shows the process flow diagram). 

Direct solvent extraction is the most widely used oil-recovery method for soybeans, but it also requires considerable capital and large scale to compete. In actual practice, solvent extraction is used to crush over 98% of the soybean processed in the United States. Process flow diagrams are shown in Figures 3 and 4. Most soybean solvent-extraction plants process more than 2,500 MT/day (Figure 5), and some are capable of processing as much as 5,000 MT/day (especially newly constructed plants in Brazil). Direct-solvent-extraction plants smaller than 1,000 MT/day have difficulty competing in the United States. At various times, soybeans have been extracted commercially with petroleum distillate fractions that resemble gasoline, acetone, carbon disulfide, ethanol, trichloroethylene, and even water. 

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