Gas locks

For impact copolymer production, a second reactor (4) in series is required. A reliable and effective gas-lock system (3) transfers powder from the first (homopolymer) reactor to the second (copolymer) reactor, and prevents cross contamination of reactants between reactors. This is critically important when producing the highest quality impact copolymer. In most respects, the operation of the second reactor system is similar to that of the first, except that ethylene in addition to propylene is fed to the second reactor. Powder from the reactor is transferred and depressurized in a gas/powder separation system (5) and into a purge column (6) for catalyst deactivation. The deactivated powder is then pelletized (7) with additives into the final products. 

Particles of polypropylene are continuously formed at low pressure in the reactor (1) in the presence of catalyst. Evaporated monomer is partially condensed and recycled. The liquid monomer with fresh propylene is sprayed onto the stirred powder bed to provide evaporative cooling. The powder is passed through a gas-lock system (2) to a second reactor (3). This acts in a similar manner to the first, except that ethylene as well as propylene is fed to the system for impact co-polymer production. The horizontal reactor makes the powder residence time distribution approach that of plug-flow. The stirred bed is well suited to handling some high ethylene co-polymers that may not flow or fluidize well. 

Replacement AHXs (RAHXs) were manufactured to an improved design which avoided the problem of gas locks and afforded greater toleration of loss of flow in individual tubes. The following changes were made and are shown in Figure 7.2. 

Encapsulated plasma devices are necessary for the plasma polymerisation processes. A continuous process, however, is stUl possible if there is a simple gas-lock at the air inlet of the reactor chamber. The production of water- and oil-repeUent layers on textiles by plasma polymerisation using fluorocarbon gases during the continuous process is already possible (Stegmaier et al. 2004). The stmctures produced by chemically deposited... 

The polymerization rate is controlled by the rate of catalyst injection to the bed. The gas velocity in the fluidized bed is maintained at about 5-10 times the weight of the fresh feed. The polymer particles are withdrawn intermittently or continuously near the distributor plate through a gas lock chamber into discharge tanks, where the ethylene gas is separated by adjusting the product withdrawal rate. 

Provision of condensate drains to avoid liquor locking Provision of vents to avoid gas locking Blanks fitted as appropriate Pipe supports... 

The direct cause for the leak was a gas lock formed in the upper leg (8) of the drain line. The lock had low temperature thereby simulating the frozen sodium. 

Until recently, many oil and gas companies considered natural gas locked in tight, impermeable shale uneconomical to produce. Advanced drilling and reservoir stimulation methods have dramatically increased gas production from unconventional shales. The Barnett Shale formation in Texas has experienced the most rapid development. The Marcellus Shale formation of the Appalachian basin, in the northeastern United States, potentially represents the largest unconventional gas resource in the United States. Other shale formations, such as the Haynesville Shale, straddling Texas and Louisiana, have also attracted interest, as have some formations in Canada. The resource potential of these shales has significantly increased the natural gas reserve estimates in the United States (Andrews, 2009). 

Pumps should be self-priming and experience no gas locking. 

The volatility of a liquid markedly increases when it is heated to or above its flash point. So a low flash point indicates appreciable evaporation losses and possibility of formation of gas-locks in fuel pipes of SPARK Ignition Engines. 

In the case of the competitive N-monochlorosulfonamide an unfavorable gas evolution was observed and gas locks made it difficult to conduct the process in a controlled way unless the nitrite concentration was lower than tens mg /L. 

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