Temperature is a critical factor in industrial reactors. A temperature controller like Delta T Systems can keep chemical elements at a stable, consistent temperature throughout the process to help ensure production success.

Local entropy generation is generated by three factors: chemical reactions, heat transfer, and pressure loss. The variations of the conditions do not affect the induced entropy considerably.

Reactor Temperature Monitoring

The temperature profile of a catalytic reactor directly influences the course and quality of the gas conversion process. It also affects the aging of the catalyst. The reliable determination of this temperature profile requires a good measurement technology. This is why Evonik, Marl, Germany, opted for innovative fiber-optic sensor technology.

In fixed-bed catalytic reactors for sale with catalyst, it is essential to monitor the temperature of the reaction volume in all its varying spatial dimensions. This enables you to detect critical operation states early and to prevent damage to the refractory layers and other structures in the reactor.

Traditional multipoint thermometers in these types of applications are positioned in vertical thermowells. However, the limited cross section of the protective tubes severely limits the number of measuring points. Lateral thermowells are difficult to install due to mechanical difficulties and high cost.

In a pilot plant, Evonik and Siemens implemented a Sitrans TO500 system with multipoint RFBG sensor technology. The sensor system consists of 24 regenerated fiber Bragg gratings (RFBG) evenly distributed over a length of 2.3 m. The sensor is capable of monitoring spatially extended temperature profiles with a resolution of 1 Hz at temperatures up to 500 degC. It also has low sensor drifts over the course of several years. The temperature data from the RFBG sensors is transmitted digitally via an electronic instrument signal, which differs from the 4 to 20 mA analog signals normally used in this type of application.

Reactor Skin Temperature Monitoring

Refineries rely on the accurate temperature monitoring of reactor tubeskin to improve performance and quality, reduce downtime and maintenance costs and boost bottom line profitability. The precise measurement of reactor skin temperatures is essential to prevent a host of problems including slowdowns, shutdowns, furnace tube failures and poor production.

Temperature sensors for monitoring the temperature of the refractory in a Claus Thermal Reactor are typically installed underneath layers of insulation to minimize heat loss and maintain the reactor operating within an optimal range. These temperatures are influenced by several factors including steam and heat tracing, hot corrosive gases, shifting refractory and ambient conditions.

Traditionally, the temperature of the refractory is monitored with a weld pad or washer thermocouple. However, these devices are not very accurate and are prone to failure due to corrosion or damage from shifting refractory.

A newer technology offers a much more reliable and durable means of measuring refractory skin temperature. It consists of a sensor/electronics unit mounted separately from the nozzle and connected to a viewing lens via a high-temperature, "non-drift" silicon thermocouple. This device is much more resistant to the high temperatures found at the nozzle and does not require the use of mercury or frequent, expensive recalibration.

The device also incorporates a secondary thermocouple that is self monitoring and able to detect the presence of an open or short circuit. This is a major improvement over the standard weld pad thermocouple as it does not rely on the constant flushing of the element well with clean, dry instrument air to ensure an accurate reading and protect against potential error caused by aging of the primary thermocouple.

Reactor Skin Temperature Control

Reactor skins are typically made of hard, durable ceramic materials like niobium and zirconia. These materials need to remain at specific temperatures in order to maintain the integrity of their structure. Fast temperature changes can cause these ceramics to fail and create hot spots on the reactor walls. These hot spots need to be monitored closely so that a refinery can take immediate action before the ceramics crack or erode.

In a hydrocracking unit, the time it takes to heat up the steel walls of the reactor can significantly impact effective MPT. For example, it may be far faster to reach MPT in a warm climate during the summer than to do so in a cold climate during the winter. These factors must be taken into account when planning startup schedules.

One way to improve the accuracy of MPT measurements is to use a resistance temperature detector (RTD) rather than a thermocouple (TC). The smaller sensor lag of an RTD offers an order of magnitude higher threshold sensitivity, repeatability and lower drift than a TC. This makes the RTD a good choice for high-speed applications. buy reactors from surplusrecord.

Reactor Jacket Temperature Control

Many industrial reactors are jacketed and consist of an inner vessel that holds chemical reactants and an outer shell (jacket) that circulates a heating or cooling fluid. Depending on the reaction type, these reactants can either be exothermic or endothermic and need to be carefully controlled to prevent temperature runaway that could damage or destroy equipment and the product.

The jacket temperature control loop is a simple system: if the reactor temperature is higher than set point, the controller signals the valve to increase the flow rate of the cooling liquid to cool the jacket vessel and lower the reactor exit stream temperature. But if the jacket temperature itself starts to rise in response to the increased flow rate, this produces a contradictory result and can confound the control algorithm and degrade controller performance.

A good solution for this problem is a bypass valve that can draw coolant directly from the jacket fluid reservoir into the cooling line. This provides additional cooling capacity quickly if the reactor temperature is increasing too fast, preventing excessive temperature build-up and thermal runaway before it’s too late.