Reactor housing

Fig. 5. Catalytic system designs (11) of (a) basic VOC catalytic converter containing a preheater section, a reactor housing the catalyst, and essential controls, ducting, instmmentation, and other elements (b) a heat exchanger using the cleaned air exiting the reactor to raise the temperature of the incoming process exhaust and (c) extracting additional heat from the exit gases by a secondary heat exchanger.

It is important to separate catalyst and vapors as soon as they enter the reactor. Otherwise, the extended contact time of the vapors with the catalyst in the reactor housing will allow for non-selective catalytic recracking of some of the desirable products. The extended residence time also promotes thermal cracking of the desirable products. 

Decreasing residence time, particularly the amount of time product vapors spend in the reactor housing before entering the main column... 

At the vapor outlet of the first-stage cyclones, an opening allows entry of stripping steam/vapors and reactor dome steam. This opening is sized to allow the second stage cyclones to be operated at a negative pressure relevant to the reactor housing pressure. 

In the KBR system, as with the ABB Lummus design, the riser cyclones are hard-piped to the riser. The diplegs of both the riser cyclone and the upper reactor cyclone are often sealed with catalyst. This minimizes the carry-under of reactor vapors into the reactor housing and maximizes the collection efficiency of the riser cyclones. 

In KBR closed cyclone technology, each set of riser and upper reactor cyclones is connected via the use of a slip joint conduit. The stripper steam and hydrocarbons, as well as dome steam, exit the reactor housing by entering through this conduit as shown in Figure 9-5. 

Eliminating long dilute-phase residence time downstream of the riser to prevent recracking of hydrocarbon vapors in the reactor housing. 

When tjjg is large compared with t, the reaction gas can be heated considerably before the heat is subtracted through the reactor housing. In the opposite case, hardly any temperature rise is observed, since heat is removed rapidly through the channel walls. 

A multitude of information is supplied on the spatio-temporal temperature evolution at the outside of the reactor housing and via conduits even within the micro reactor (bottom) [15]. 

Micro reactor housing material Nickel Reactor No. 3 total number of reaction channels 49... 

The reactor assembly was heated by electric heaters. The maximum operating temperature Is determined by the window construction. Sapphire windows (from EIMAC), brazed into Kovar sleeves, were used the sleeves were then welded directly into the stainless steel reactor housing. We found that the cell so constructed was capable of trouble-free, continuous operation at 450°C operations at somewhat higher temperatures are probably still possible but were not explored. Sapphire was chosen as a window material because it is insensitive to water vapor and is transparent in tljie wave number range of our interest (about 2400 cm to 2000 cm in these experiments). Moreover, the thermal expansion characteristics of the reactor were found to match well with those of the window fixture. 

Figure 2.29 Photograph of the ceramic reactor housing and the quartz-glass tubulare microreactor (visible through the center hole) [59].

In a microstructured reactor plant, in contrast, the flow rate will be dominated by the pressure loss. Typical pressure losses in micro devices are of the order of 1 bar at a flow of 11 h 1 (water) [50,93], If sufficient pump capacity is available, the pressure loss in a micro structured device is limited by the mechanical stability of the reactor housing, which is often made of steel and hence a loss of several bar is certainly acceptable. Even the combination of up to 10 different micro devices only amounts to about 10 bar in this example. The main advantage of a micro structured reactor plant is that the flow rate can be adjusted more freely because the flow is pressure driven and not influenced by a single gravity-driven device as in a miniplant. 

The dimensions of the stainless-steel micro structured reformer are 75 mm x 45 mm x 110 mm. It consists of a stack of micro structured steel foils coated with catalyst and tempered by heating cartridges in the reactor housing. Laser-cut graphite foils were used to seal the reformer under operating conditions up to 200 °C at a flow rate up to 900 ml min-1 and a residence time of 0.07 s. 

Reactor 21 [R 21] Hybrid Set-up of Mini-scaled and Micro Structured Components Inside a Reactor Housing... 

Ceramic materials typically have low tensile strengths compared to compressive strengths which arc five to ten times higher. Therefore, the ccramic-to-mctal joint construction should only impose compressive stress on the ceramic-metal interface. This, for example, can be achieved through the use of a metallic bellow. By joining the bellow directly to the porous ceramic element and welding the bellow under compressive conditions to the module or reactor housing, the joint will stay at all times under a compressive force [Velterop and Keizer, 1991]. To reinforce the joint, a dense... 

Recently, through the agency of a microwave reactor housing thick quartz vessels that could withstand pressures of 8 MPa and heat water to 300 °C, Kremsner and Kappe have conducted more interesting research into several aspects of the topics described above [40]. 

Figure 25.9 Scheme of the reactor housing (left) and photograph (middle) ofthe heat-shielded reactor under operation (gold mirror becomes transparent) [40] and different reactor sizes (right inset magnification of microchannel structure) [47]. 

The unit consists of the reactor, housing the core with actuators of the scram and compensation control rod groups, two steam generators that are connected to the reactor vessel with short nozzles, and two hydraulic chambers accommodating the electric pumps. 

It is easy to use this definition for large scale fixed beds, because the porosity of the catalyst and of the catalyst bed are easy to measure and in most instances the reactor housing contributes to the overall volume only to a minor extent. However, the definition becomes doubtful when the catalyst is coated onto a monolith or foam. Here the question arises as to which volume is then being referred to the volume of the catalyst coating itself, of the monohth void fraction (channels) or of the entire monolith All these questions need to be clarified before a fair comparison of catalytic activity is feasible when gas hourly space velocity is applied for the calculations. 

Figure 7.8 Integrated reformer/combustor for methanol steam reforming (A) S shaped metal foils (B) reactor housing [499],...

Fig. 2.21 Combined aftertreatment system for a shunting locomotive a DPF -I- SCR installed in one reactor housing, b gas flow (Picture MTU) with A exhaust gas inlet, 1 diesel oxidation catalyst (DOC), 2 diesel particulate filter (DPF), 3 urea solution Injection, 4 SCR catalyst, 5 ammonia slip catalyst (ASC), 6 urea mixing area, B exhaust gas outlet...

The station is situated on the coast on the western side of Dungeness in Kent. There are two reactors, housed in spherical-type pressure vessels of 62.5 ft mean diameter, constructed of steel plates having a general thickness of 4 in. Each reactor has four boilers. Generating plant comprises four 1,500 rpm turbo alternators each with rated output of 142.5 MW at 0.8 power factor (lagging). The total guaranteed net output of the station in megawatts is planned as 550 MW which was expected to be achieved by the end of 1965. 

This Japan Atomic Power Company s Tokai nuclear power station is situated on the Pacific coast about 70 miles north-east of Tokyo. The station is a single reactor housed in a skirt-supported spherical pressure vessel having a mean diameter of... 

Each station consists of four reactors housed in cylindrical mild steel pressure vessels which are 70/71 ft high and 37 ft in diameter. Six fuel elements are stacked vertically in each of the 1696 channels per reactor. Each reactor has four heat exchangers generating high- and low-pressure steam simultaneously. Generating plant comprises eight 3000 rpm turbo alternators. 

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