φ800甲醇精餾塔設(shè)計(jì)（全套CAD圖+說(shuō)明書+開題報(bào)告+翻譯）
φ800甲醇精餾塔設(shè)計(jì)（全套CAD圖+說(shuō)明書+開題報(bào)告+翻譯）,甲醇,精餾塔,設(shè)計(jì),全套,cad,說(shuō)明書,仿單,開題,報(bào)告,講演,呈文,翻譯
附 錄
Energy-saving technology of distillation process
Abstract: Distillation is a chemical, petrochemical, pharmaceutical and other important unit operation in process; this paper focuses on energy-efficient distillation process. Heat from the distillation process full use; improve the separation efficiency of distillation systems, improve product recovery to achieve lower energy consumption; reduce the energy needs of the distillation process and the strengthening of management aspects, discusses in detail the energy-saving technology of distillation process.
Keywords: distillation; energy
1 Introduction
In industrial production, petrochemical industry, the largest proportion of energy consumption, while energy consumption in the petrochemical industry for the greatest separation operation, among which the energy consumption of distillation the first place. Distillation process is a complex heat and mass transfer process, as follows: the process of multi-variable, controlled variable and more controllable variables are many; process and mechanism of complex dynamic. "
First, with the rapid development of petrochemical industry, distillation is more and more widely, increasing separation of the components of materials, separation of the product purity requirements are being improved, but people also do not want to consume too much energy, which the control of the distillation process to make a request. Secondly, as a chemical production process of the most widely separated, large energy-consuming distillation is a chemical unit operation. In the actual production in order to ensure qualified products, distillation unit operation is often conservative, methods of operation and operating parameters are often less reasonable. In addition, because the energy consumed most of the distillation process is not used for component separation, but was taken away by cooling water or separate components. Therefore, the distillation process is great potential for energy saving and rational use of thermal distillation process itself, the whole process can reduce the energy demand, reduce energy waste of energy is also very effective obvious.
According to statistics, the energy consumption of distillation process in the United States accounted for 3% of the national energy consumption, saving from 10% if the annual savings of $ 500,000,000. China's consumption of crude oil refinery of its refining capacity of 8% to 10%, much of it consumed in the distillation process. Thus, in the case of the current energy shortage, saving of the process of distillation is very important. For example, the United States in Puerto Rico Bartels aromatics unit 8 of distillation column optimization energy on the operation, annual savings of $ 3,100,000.
Energy-efficient distillation process basically from the following aspects: (1) full utilization of heat distillation process; (2) increase the separation efficiency of distillation systems, improve product recovery to achieve lower energy consumption; (3) reduction of distillation process on the energy needs; (4) to strengthen management.
2, the full utilization of the distillation process heat
2.1 strengthened to improve the thermal insulation cold use
In the distillation equipment used in the distillation column and the main heat exchanger, in addition to a variety of channels, these devices are mostly made of metal, is easier to heat conduction, combined with the impact of ambient temperature, if taken to its cold insulation measures can greatly reduce the equipment and the role of heat transfer between the environment, so as to achieve the purpose of saving energy.
Strengthen the recoiled and condenser heat transfer temperature difference in heat transfer can decrease, due to reduced temperature difference can make top coolant temperature rises, the heating temperature drop tower reactor. This includes enhancing the heat transfer area and the use of air coolers or evaporative coolers instead of water coolers and other methods.
2.2 The high-temperature materials, sensible heat and latent heat utilization
High-temperature materials from the distillation column itself is carrying out a lot of heat, this part of the heat energy for recycling is also a. Such as: (1) high temperature distillation tower materials recovered latent heat of steam, the top condenser for the steam generator. Operating pressure of 32 K Pa, such as crude styrene tower, the top material can be used for heating steam into the reactor for ethyl benzene dehydrogenation. This arrangement allows energy per ton of styrene products (2) the top of the tower, tower reactor materials and raw materials for heat transfer fluid through the top material to the heating of raw materials. This will not only take advantage of the tower, tower reactor materials, waste heat, but can also reduce the overhead condenser cooling capacity usage.
2.3 Using pinch technology for heat exchanger network optimization
For a chemical system, when a number of shares of heat and cold more than shares of the heat exchanger, the heat can be combined into one all hot composite curve, all combined into a cold composite curve, and then the two together means that A temperature enthalpy diagram, the pinch point is the enthalpy diagram in the temperature of a hot and cold composite curves coincide at a point when the heat transfer within the system limit of coincidence points of the temperature difference is zero, the point is the pinch point. Temperature is below zero at the pinch point, you need an infinite heat transfer area, can be determined by technical and economic evaluation of a system of minimum temperature difference - pinch point temperature difference, so pinch point can be defined as hot and cold temperatures combined online where the minimum temperature difference. In the synthesis of heat exchanger networks using pinch technology to consider a variety of logistics match, heat exchanger network can make optimal use of the heat.
3, the separation distillation system to improve efficiency and product recovery More than
3.1 effect distillation technology the general multi-effect distillation process shown in Figure 1.
Multi-effect distillation from the N-parallel operation of a distillation column composition, as shown in Figure l operating efficiency by reducing the pressure from left to right. Top high pressure in front of the tower behind the low pressure steam as the bottom recoiled heating medium, in which the condensation. If two adjacent tower recoiled condenser and the heat load balance, only the first tower to be heated recoiled steam, the last tower of the condenser cooling medium needs. By N-effect distillation, and then boiling the steam required for heating can be reduced to the original single-effect heat required for steam distillation I / N or so. Practice shows that the heat required for distillation of two effective single-effect distillations and comparison can be reduced by 30 to 40%.
Fig.1 Multi-effect distillation technology
3.2 The low-temperature heat pump distillation technology
when using a refrigerant condenser cooling tower is called low-temperature distillation. Cryogenic distillation at a lower pressure. And because the larger the relative volatility at low temperature, reflux ratio can be smaller to reduce the condenser and recoiled heat load.
Single-effect distillation and heat pump pumping heat from the condenser to the recoiled of the low-temperature distillation, known as the heat pump distillation. Heat pump distillation can reduce energy consumption. To top steam condensation heat released when the recoiled provides the heat source as the gasification chamber, the use of the expansion valve and compressor to change the temperature of condensation or boiling. Figure 2 shows the most simple distillation with heat pump, in the top condenser and bottom recoiled joint between the closed loop on an additional refrigerant, refrigerant evaporates in the top condenser absorbs heat, and then Compressed by the compressor, cooling tower kettle recoiled and release heat, and then the throttle to the top of the tower condenser vacuum evaporation. So again, keep the heat pumped from the condenser to the low temperature high temperature recoiled.
1. Distillation column; 2. Compressor; 3. Recoiled; 4. Throttle
Fig.2 Distillation heat pump technology
3.3 Fully Thermally Coupled Distillation Column Technology
Fully Thermally Coupled Distillation Column 60 years of the 20th century's a complex distillation technology, mainly for the separation of ternary mixtures. The type of the tower had been in 1989, the first by the German company BASF to achieve industrialization, as compared with conventional distillation column thermally coupled distillation can save energy up to 30%. Can use a full tower and a deputy instead of two complete distillation tower, full tower from the liquid phase leads to an associate Tata logistics directly as the top of the liquid reflux, gas logistics directly leads to an end as Vice Tata Gas return to avoid the use of condensers and vice tower recoiled, to achieve the coupling of heat, called thermal coupling distillation.
Thermocouple distillation in thermodynamics is the ideal system architecture can save equipment investment, but also save energy. Calculations show that thermal coupling distillation tower than the two conventional distillations can save energy 30%. Japan's Sumitomo Heavy Industries Ltd. and Krupp Uhde completed the industrialization of thermally coupled distillation tower, crude purification company in the United States UOP device heptanes distillation column using a vertical partition (thermally coupled distillation column a). It uses multiple feed technologies, and includes the absorption process. The development trend from the recent years, thermally coupled distillation of good prospects for industrial applications.
Agrawal and Fidkowski thermodynamic efficiency from the point of view, the ideal of the separation of three Yuan saturated liquid thermally coupled distillation sequence with the conventional differences. Schultz and put forward a number of thermally coupled distillation used rules of thumb that the selection of thermally coupled distillation are: the content of the feed components are more middle of the light key component and intermediate component and the relative volatility between components and heavy key components of the relative volatility between the close. Lu Xiang Hong, Lu en xi rigorous distillation model calculations to simulate the separation of mixture of three components thermally coupled distillation columns and sequences of the energy consumption of conventional simple distillation, thermally coupled distillation column application of the precondition, and to recommend thermally coupled distillation principle of selection : (1) When the separation index ESI 1 when not in use thermally coupled distillation program. (4) If the conventional distillation tower operating pressure difference larger, and is not used thermally coupled distillation program.
3.4 distillations tower internal heat integration
Heat integration within the distillation column (Internally Heat Integrated Distillation Column, referred to as HIDiC), refer to the same section of the tower itself and the stripping section of distillation for heat integration. It is through the distillation column rectifying section and stripping section of the heat integrated distillation column to achieve the non-operation of condenser and recoiled, thus greatly reducing the energy consumption compared with conventional distillation energy savings up to 30 ~ 60 %; This is the biggest ever known energy, the most advanced type of distillation column. The idea was first in the 20th century, 60 years mountain Freshwater proposed, and then there have been scholars have published research results. Japanese scholar M. Nakaiwa other experimental studies on the basis of complete, was adopted in 2000 in the trial of the tower, the current is moving in the direction of industrialization and progress.
Heat integration within the traditional distillation tower and has a very big difference: the traditional distillation tower essential kettle top condenser and recoiled are no longer needed, the original is divided into a distillation column distillation and stripping two towers, distillation tower placed in the stripping rate.
ListenRead phonetical?HIDiC the energy conservation principle can be McCabe-Thiele (MT) Chart interpretation. Figure 4 is a conventional distillation tower MT map, the rectifying section and stripping section operating line for the two lines. The figure, XD is the mole fraction of top product composition, XB is the mole fraction of the tower reactor product composition, X is the mole fraction of feed composition, x, y, respectively volatile components in the composition of liquid and gas phase mole fraction. Mass transfer driving force for the operating line and equilibrium line distance between its non-equivalent distribution along the tower, the feed board at the minimum, to the gradual increase in both ends of the tower. This is a major cause of a high degree of irreversibility, the operating line and equilibrium line the greater the vertical distance between the effective energy losses will be. The abolition of the condenser and HIDiC tower recoiled, making operating line and equilibrium line into a shape similar to the curve shown in Figure 5. Thus HIDiC tower has a high thermodynamic efficiency.
3.5 using the new high efficiency separation technology
Separation are achieved through the tower equipment. Transformation of the conventional plate tower, high-efficiency-oriented screen, but can reduce energy consumption and increase production capacity.
3.5.1 Efficient guided sieve tray
Efficient guided sieve tray is included in the Beijing University of Chemical Technology, including a variety of sieve plate tray depth and detailed study based on a simple structure to play a sieve tray, the characteristics of low cost, to overcome the leakage of high and low efficiency disadvantages, and through in-depth study of various plates, and comprehensive comparisons with Tray science of hydrodynamics and mass transfer research and development of a new and efficient tray, and its working principle is shown in Figure 6. High efficiency-oriented guided sieve tray is opened a large mesh sieve and a small part of the pilot hole through the sieve plate and the liquid gas in the wrong tower flow through the liquid layer vertical rise, driven by the gas along the sieve tray level forward, the momentum transfer to the Tower board level flow of liquid, so as to promote uniform and stable liquid in the tray plate forward, to overcome the gap between the original tower panel and liquid back-mixing liquid, increase the production capacity and the board efficiency to solve the block tower, night pan and other issues. In addition, the board in the traditional tower, due to surface gradient, upstream of the plate there is always a non-active area; flow in this region can not rise through the bubbling liquid layer. Experimental determination, non-activation of the areas of the cross-sectional area of ??the tower about 1 / 3. Efficient sieve in the flow direction increased the convex entrance ramps into the bubble-like facilitator to promote the liquid into the tray can generate a bubble, bringing a good gas-liquid contact and mass transfer. Efficiency-oriented sieve has the following characteristics: (1) production capacity; (2) high efficiency; (3) pressure drop; (4) anti-blocking capability; (5) simple structure, low cost
3.5.3 The new high efficiency packing
Packing tower packing is the most important mass transfer within the parts; its performance depends on the filler surface the wet body of the extent and distribution of gas-liquid two-phase flow uniformity.
(1) new and efficient structured packing
New high efficiency metal structured packing including packing and metal mesh packing two categories, in its physical and chemical treatment process, filling the separation efficiency greatly improved. Main advantages are: (1) the high number of theoretical plates, flux, and pressure is reduced. (2) low-load performance, number of theoretical plates decreased with the increased gas load, no low load limit. (3) Amplification effect is not obvious. (4) For vacuum distillation, to meet the sophisticated, large-scale, high-vacuum distillation unit requirements, difficult isolates Department, heat-sensitive materials of high purity product lines and provide a distillation of favorable conditions.
(2) new high efficiency random packing
Metal Pall ring packing 40 years of the 20th century German BASF Ranching ring packing in the development of the basis. It uses red sheet metal rolled into the ring out of the wall with 2 rows of fenestrate within the Sense leaves, each row of 5 windows bends leaf tongue rings pointing into the ring with a heart, almost in the center relative to take, F 2 layer on a staggered position of fenestrate, the general opening of the ring area of ??the total area of ??about 35%. Because many of the ring walls opened windows, so fill layer of gas and liquid distribution and mass transfer performance la Xi ring has greatly improved.
(3) Ladder ring packing 70 in the early 20th century by the British mass value of the company developed a technology to improve the whole ring packing. Such fillers reduce the height of ring, and the two side of the ring increases tapered end flange, its performance compared with Pall ring packing made greater progress. In the same density of the liquid spray, its pan-point velocity increased more pall ring 10 to 20%; in the same gas velocity, the pressure drop lower than the Pall ring 30 to 40%.
(4) Filler metal ring Interlocks this is America, Norton (Norton) has pioneered the research and development of a new type of filler, the British domestic Troy Cox referred to as filler. This filler skillfully and saddle ring features two types of packing consolidated into one, making it both the characteristics of the ring packing flux, there are saddle-shaped distribution of good performance characteristics of liquid filler, powder filling compound to become leader. New high fill dozens of companies have been applied towers are made expansion, energy conservation, energy, greatly improving economic results.
4, reducing the energy needs of distillation process
Distillation process to reduce the need for energy is a fundamental energy-saving method, the main separation sequence should consider the selection and optimization of operating conditions.
4.1 Optimization of the order of multi-tower distillation
Use of N-component distillation column series will be separated from the towers to be N-1, and the order can have a variety of its programs, the number of its programs available expression S = [2 (m-1)]! / M! (M-1)! That (where m is group scores). For example, there are three components arranged in two programs, there are 42 six-component programs, select a major impact on energy consumption will be good or bad. Separation sequence in the choice, you can refer to the following principles: (1) should be key components of the relative volatility of the closest to 1, t
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