Process design vacuum jets

The third difference is that many process details are relatively uncertain when a plant is designed. For example, iaert loading for vacuum jets is rarely known to within 50%. Although the first two differences are negative, the third provides a unique opportunity to measure the tme need and revise the system accordingly. 

In addition, the process engineer must be aware of good design practices for vacuum jets. 

The process designer or mechanical engineer in a process plant is not expected to, nor should he, actually design a mechanical vacuum pump or steam jet, biit rather he should be knowledgeable enough to establish the process requirements for capacity, pressure drops, etc., and understand the operation and details of equipment available. 

There is no vacuum source that is the best choice for every application. The technology for protecting mechanical pumps from process upsets and abuse is highly developed. This technology can be used effectively in designed vacuum systems to meet specific requirements. In several applications, mechanical pumps have demonstreted reliability comparable with, or superior to, liquid-ring pumps or steam jet ejectors. 

Process vapours from the esterification reactors and EG from the EG-vapour jet, as well as from the vacuum stages of the spray condensers, are purified in the distillation unit. The distillation unit commonly consists of two or three columns and is designed for continuous operation. The purified EG is condensed at the top of the third vacuum rectification column and returned to the process via a buffer tank. Gaseous acetaldehyde and other non-condensables are vented or burned and high-boiling residues from the bottom of the third column are discharged or also burned. 

The situation inside monitoring module CCD is designed and installed to test the change of explosion gas jet-flow in vacuum module and whether vacuum module is damaged or not in the experimental process. 

The maximum compression ratio achievable by a jet usually is about 6 or 10 1. Practically, ratios are limited to lower values, and multistage jets are necessary in evaporation systems. While process and equipment design have much to do widi flie selection of the number of stages, the tabulation below is a rough guide to the absolute pressures that can be produced by two to four vacuum stages ... 

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