scholarly journals Comparison of Temperature Control and Temperature Difference Control for a Kaibel Dividing Wall Column

Processes ◽  
2019 ◽  
Vol 7 (10) ◽  
pp. 773 ◽  
Author(s):  
Xing Qian ◽  
Rui Liu ◽  
Kejin Huang ◽  
Haisheng Chen ◽  
Yang Yuan ◽  
...  
Keyword(s):  
Temperature Control ◽  
Temperature Difference ◽  
Capital Investment ◽  
Temperature Sensors ◽  
Distillation Process ◽  
Control Structures ◽  
Dividing Wall Column ◽  
Dynamic Performances ◽  
Two Temperature ◽  
Better Than

A dividing wall column (DWC) effectively intensifies the distillation process with a reduced energy consumption, capital investment, and space. The three-product DWC has been investigated intensively and extensively; however, the four-product Kaibel DWC has received scarce attention. This study aimed to propose feasible control structures for the Kaibel DWC using only temperature sensors in order to promote its industrialization. Two temperature control structures, two temperature difference control structures, and two double temperature difference control structures were studied. The feasibility of the six proposed control structures was verified with a wide variety of feed disturbances. In most cases, temperature difference control was better than temperature control to maintain product purities. The dynamic performances proved that the inserted feed disturbances were handled well. These results help to promote the industrialization of the Kaibel DWC.

scholarly journals Controllability Comparison of the Four-Product Petlyuk Dividing Wall Distillation Column Using Temperature Control Schemes

Processes ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 116 ◽  
Author(s):  
Xing Qian ◽  
Rui Liu ◽  
Kejin Huang ◽  
Haisheng Chen ◽  
Yang Yuan ◽  
...  
Keyword(s):  
Temperature Control ◽  
Temperature Difference ◽  
Feed Rate ◽  
Distillation Column ◽  
Process Intensification ◽  
Distillation Columns ◽  
Operation Costs ◽  
Control Scheme ◽  
Control Schemes ◽  
Dynamic Performances

An effective process intensification strategy based on dividing walls shows promising energy-saving results for distillation processes. The three-product Petlyuk dividing wall distillation columns (DWDCs) are able to save approximately 30% energy in comparison with the traditional distillation columns. Furthermore, the four-product extended Petlyuk DWDC reduces about 50% of operation costs than conventional distillation sequences. Although researchers have extensively studied control schemes for the three-product Petlyuk DWDC, relatively little work has been done on the four-product extended Petlyuk DWDC. This paper studies feasible temperature control schemes containing temperature control scheme (TC), simplified temperature difference control scheme (STDC), and simplified double temperature difference control scheme (SDTDC) for the four-product extended Petlyuk DWDC. STDC and SDTDC are introduced so as to improve the dynamic performances with simple control schemes. All three control schemes are tested against a series of feed compositions and feed rate disturbances. Dynamic performances prove that the proposed STDC and SDTDC schemes are better at handling the inserted feed disturbances. These are very encouraging results for industrialization of the four-product extended Petlyuk DWDC in the future.

A High Angle, Double Tilting Cold Stage for the AEI EM7

1974 ◽  
Vol 32 ◽  
pp. 450-451
Author(s):  
P.R. Swann ◽  
A.E. Lloyd
Keyword(s):  
Habit Plane ◽  
Temperature Control ◽  
Tilt Angle ◽  
Cooling System ◽  
Thermal Drift ◽  
High Angle ◽  
Cold Stage ◽  
High Degree ◽  
Better Than

Figure 1 shows the design of a specimen stage used for the in situ observation of phase transformations in the temperature range between ambient and −160°C. The design has the following features a high degree of specimen stability during tilting linear tilt actuation about two orthogonal axes for accurate control of tilt angle read-out high angle tilt range for stereo work and habit plane determination simple, robust construction temperature control of better than ±0.5°C minimum thermal drift and transmission of vibration from the cooling system.

scholarly journals Corporate Governance, Economic Entrenchment, and Growth

2005 ◽  
Vol 43 (3) ◽  
pp. 655-720 ◽  
Author(s):  
Randall Morck ◽  
Daniel Wolfenzon ◽  
Bernard Yeung
Keyword(s):  
Corporate Governance ◽  
Capital Investment ◽  
Corporate Control ◽  
Political Influence ◽  
Institutional Development ◽  
The United States ◽  
Firm Level ◽  
Control Structures ◽  
Resource Misallocation ◽  
Property Rights Protection

Outside the United States and the United Kingdom, large corporations usually have controlling owners, who are usually very wealthy families. Pyramidal control structures, cross shareholding, and super-voting rights let such families control corporations without making a commensurate capital investment. In many countries, a few such families end up controlling considerable proportions of their countries' economies. Three points emerge. First, at the firm level, these ownership structures, because they vest dominant control rights with families who often have little real capital invested, permit a range of agency problems and hence resource misallocation. If a few families control large swaths of an economy, such corporate governance problems can attain macroeconomic importance—affecting rates of innovation, economywide resource allocation, and economic growth. If political influence depends on what one controls, rather than what one owns, the controlling owners of pyramids have greatly amplified political influence relative to their actual wealth. This influence can distort public policy regarding property rights protection, capital markets, and other institutions. We denote this phenomenon economic entrenchment, and posit a relationship between the distribution of corporate control and institutional development that generates and preserves economic entrenchment as one possible equilibrium. The literature suggests key determinants of economic entrenchment, but has many gaps where further work exploring the political economy importance of the distribution of corporate control is needed.

Temperature Control and Anti-Cracking Measures for a High-Performance Concrete Aqueduct

2013 ◽  
Vol 405-408 ◽  
pp. 2739-2742 ◽  
Author(s):  
Zhen Hong Wang ◽  
Shu Ping Yu ◽  
Yi Liu
Keyword(s):  
Temperature Control ◽  
Temperature Difference ◽  
High Performance ◽  
High Performance Concrete ◽  
Concrete Structures ◽  
Apparent Temperature ◽  
Mass Concrete ◽  
Water Pipe ◽  
Thin Walled ◽  
Water Pipe Cooling

To solve the problem of cracks developing on thin-walled concrete structures during construction, the authors expound on the causes of cracks and the crack mechanism. The difference between external and internal temperatures, basic temperature difference and constraints are the main reasons of crack development on thin-walled concrete structures. Measures such as optimizing concrete mixing ratio, improving construction technology, and reducing temperature difference can prevent thin-walled concrete structures from cracking. Moreover, water-pipe cooling technology commonly used in mass concrete can be applied to thin-walled concrete structures to reduce temperature difference. This method is undoubtedly a breakthrough in anti-cracking technology for thin-walled concrete structures, particularly for thin-walled high-performance concrete structures. In addition, a three-dimensional finite element method is adopted to simulate the calculation of temperature control and anti-cracking effects f. Results show the apparent temperature controlling effect of water-pipe cooling for thin-walled concrete structures.

A Fast and Accurate Temperature-Control System Using Smart Temperature Sensors.

1998 ◽  
pp. 247-254
Author(s):  
Paul R. van der Meer ◽  
Gerard C. M. Meijer ◽  
Michiel J. Vellekoop ◽  
Harry M. M. Kerkvliet ◽  
Ton J. J. van den Boom
Keyword(s):  
Control System ◽  
Temperature Control ◽  
Temperature Sensors ◽  
Temperature Control System ◽  
Accurate Temperature ◽  
Accurate Temperature Control

A near-ambient-temperature-control cell for use with synchrotron X-ray powder diffraction

1995 ◽  
Vol 28 (5) ◽  
pp. 651-653 ◽  
Author(s):  
R. J. Cernik ◽  
S. R. Craig ◽  
K. J. Roberts ◽  
J. N. Sherwood
Keyword(s):  
Powder Diffraction ◽  
Temperature Control ◽  
Low Cost ◽  
Control Cell ◽  
Temperature Stability ◽  
Free Rotation ◽  
Melting Points ◽  
X Ray ◽  
Rotator Phase ◽  
Better Than

A low-cost cell has been designed and built for synchrotron X-ray powder diffraction studies of materials with low melting points. The cell has been operated between 253 and 323 K with a temperature stability of better than 0.1 K. The construction of the cell allows free rotation of the sample during a scan in order to maximize the number of powder grains in the reflecting position. The cell has been used to study a transition from an ordered to a rotator phase in hexadecane occurring at 278 K and the results from that study are reported.

Digital temperature programmer with two temperature sensors

1981 ◽  
Vol 21 (1) ◽  
pp. 163-171 ◽  
Author(s):  
S. Gál ◽  
J. Muráti ◽  
J. Sztatisz
Keyword(s):  
Temperature Sensors ◽  
Two Temperature
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