CN1188375C - Method for demethanizing in ethylene production - Google Patents
Method for demethanizing in ethylene production Download PDFInfo
- Publication number
- CN1188375C CN1188375C CNB011183594A CN01118359A CN1188375C CN 1188375 C CN1188375 C CN 1188375C CN B011183594 A CNB011183594 A CN B011183594A CN 01118359 A CN01118359 A CN 01118359A CN 1188375 C CN1188375 C CN 1188375C
- Authority
- CN
- China
- Prior art keywords
- tower
- rectifying
- enters
- gas
- liquid
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Images
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
- F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
- F25J3/0204—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the feed stream
- F25J3/0219—Refinery gas, cracking gas, coke oven gas, gaseous mixtures containing aliphatic unsaturated CnHm or gaseous mixtures of undefined nature
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
- F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
- F25J3/0228—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the separated product stream
- F25J3/0233—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the separated product stream separation of CnHm with 1 carbon atom or more
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
- F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
- F25J3/0228—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the separated product stream
- F25J3/0238—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the separated product stream separation of CnHm with 2 carbon atoms or more
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
- F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
- F25J3/0228—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the separated product stream
- F25J3/0252—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the separated product stream separation of hydrogen
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J2200/00—Processes or apparatus using separation by rectification
- F25J2200/50—Processes or apparatus using separation by rectification using multiple (re-)boiler-condensers at different heights of the column
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J2200/00—Processes or apparatus using separation by rectification
- F25J2200/74—Refluxing the column with at least a part of the partially condensed overhead gas
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J2200/00—Processes or apparatus using separation by rectification
- F25J2200/78—Refluxing the column with a liquid stream originating from an upstream or downstream fractionator column
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J2210/00—Processes characterised by the type or other details of the feed stream
- F25J2210/12—Refinery or petrochemical off-gas
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P30/00—Technologies relating to oil refining and petrochemical industry
- Y02P30/40—Ethylene production
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Mechanical Engineering (AREA)
- Thermal Sciences (AREA)
- General Engineering & Computer Science (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
本发明属于化工技术领域，利用多级逆流精馏塔对经过压缩干燥换热后的裂解气中的轻重组分进行初步分离和直接换热，将脱除部分轻组分的裂解气送入脱甲烷塔进一步分离。脱甲烷塔在-72至-75℃操作运行，顶部尾气采用吸收塔AD1进行回收乙烯，回收乙烯后剩余的甲烷和氢气，进一步处理得到纯净的氢气产品。吸收负载的乙烯经解吸后回收。本发明具有降低脱甲烷系统的运行能耗、减少设备投资的特点。
The invention belongs to the technical field of chemical industry. The light and heavy components in the pyrolysis gas after compressed drying and heat exchange are preliminarily separated and directly exchanged by using a multi-stage countercurrent rectification tower, and the cracked gas from which part of the light components have been removed is sent to the decompression gas. The methane column is further separated. The demethanizer operates at -72 to -75°C, and the top tail gas uses the absorption tower AD1 to recover ethylene, and the remaining methane and hydrogen after recovery of ethylene are further processed to obtain pure hydrogen products. The absorbed ethylene is recovered after being desorbed. The invention has the characteristics of reducing the operating energy consumption of the demethanization system and reducing equipment investment.
Description
本发明属于化工技术领域，特别涉及一种用于乙烯生产中脱甲烷的工艺新方法。The invention belongs to the technical field of chemical industry, and particularly relates to a new process method for demethanization in ethylene production.
脱甲烷过程是乙烯生产过程的重要组成部分。其中脱甲烷过程主要包括两个步骤：原料的预冷和脱甲烷。目前用于生产中的深冷脱甲烷过程一般可分为高压法、低压法和ARS等方法。高压法的主要操作条件为高压预冷(3.4MPa)，高压脱甲烷(2.94MPa)，低压法的主要操作条件为高压预冷(3.4Mpa)和低压脱甲烷(0.59MPa)。低压脱甲烷可提高甲烷和乙烯的相对挥发度，大大降低了最小汽提量和最小回流比(低压系统为0.1-0.2，高压系统为0.8～1.0)，从而节省了能量。但低压脱甲烷流程不适合所有的裂解原料，只适用于裂解产品的CH4/C2H4较大的场合。The demethanization process is an important part of the ethylene production process. The demethanization process mainly includes two steps: precooling of raw materials and demethanization. The cryogenic demethanization processes currently used in production can generally be divided into high-pressure methods, low-pressure methods, and ARS methods. The main operating conditions of the high pressure method are high pressure precooling (3.4MPa), high pressure demethanization (2.94MPa), and the main operating conditions of the low pressure method are high pressure precooling (3.4Mpa) and low pressure demethanization (0.59MPa). Low-pressure demethanization can increase the relative volatility of methane and ethylene, and greatly reduce the minimum stripping volume and minimum reflux ratio (0.1-0.2 for low-pressure systems and 0.8-1.0 for high-pressure systems), thereby saving energy. However, the low-pressure demethanization process is not suitable for all cracking raw materials, and is only suitable for occasions where the CH 4 /C 2 H 4 of the cracking product is large.
ARS技术，即先进分离技术(Advanced Recovery System)是Stone Webster公司与Mobil化学公司共同开发的先进的烯烃回收新工艺。该技术采用冷凝分离器，在脱甲烷塔之前，将裂解气中的氢气，甲烷尽可能多的分离出来，使脱甲烷塔可在较高温度下操作，因而取消了-101℃的乙烯冷剂，这是该技术的最大特点和优点。ARS technology, or Advanced Recovery System, is a new advanced olefin recovery process jointly developed by Stone Webster and Mobil Chemical. This technology uses a condensation separator to separate the hydrogen and methane in the cracked gas as much as possible before the demethanizer, so that the demethanizer can be operated at a higher temperature, thus canceling the -101 ℃ ethylene refrigerant , which is the biggest feature and advantage of this technology.
与高压法相比，尽管ARS技术和低压脱甲烷技术具有一定的节能作用，但在工业实施过程中都需要极低的温度(一般维持在-99℃)，消耗大量冷剂，相应的设备材质需要采用3.5Ni钢或不锈钢，管道材质也要全部用不锈钢。同时整个系统存在两相流动，为了减小压降需要采用较大的管道尺寸，这些因素制约了低压脱甲烷技术的进一步发展。Compared with the high-pressure method, although the ARS technology and the low-pressure demethanization technology have a certain energy-saving effect, they both require extremely low temperatures (generally maintained at -99°C) during industrial implementation, consume a large amount of refrigerant, and require corresponding equipment materials. Use 3.5Ni steel or stainless steel, and all pipe materials should be stainless steel. At the same time, there is two-phase flow in the whole system, and a larger pipe size is required to reduce the pressure drop. These factors restrict the further development of low-pressure demethanization technology.
本发明的目的是为克服已有技术的不足之处，提出一种用于乙烯生产中脱甲烷的方法，采用高压状态(2.94MPa)脱甲烷，使其具有降低脱甲烷系统的运行能耗、减少设备投资的特点。The purpose of the present invention is to overcome the deficiencies in the prior art, propose a method for demethanization in ethylene production, adopt high-pressure state (2.94MPa) demethanization, make it have the operation energy consumption of reducing demethanization system, Features that reduce equipment investment.
本发明提出一种用于乙烯生产中脱甲烷的方法，其特征在于，包括以下步骤：The present invention proposes a method for demethanization in ethylene production, characterized in that it comprises the following steps:
(1)经过压缩干燥换热后的裂解气，在脱甲烷塔中间再沸器中冷却进入第一精馏塔DT1底部；DT1精馏塔分为上下A、B两个独立的部分，下部精馏段B的汽相采出，用脱乙烷塔釜液冷却至-26℃~-30℃后又在进料激冷器里用-40℃丙烯冷剂冷却到-37℃~-38℃，进入分离器SP2分离；分离器分出的凝液送回下部B精馏部分做回流；未冷凝的气体作为再沸气体进入上部A精馏部分，上部精馏A的液体也进入下部B精馏部分做回流：这样，通过第一精馏塔传质传热的塔釜釜液进入脱甲烷塔DA-301，而第一精馏塔上部精馏A部分的顶部气相经冷箱CD1和乙烯冷剂冷凝，进入汽液分离罐SP1，气相进入第二精馏塔DT2下部精馏C部分的塔釜，液相则进入第一精馏塔DT1顶A部分作为回流；(1) The cracked gas after compression, drying and heat exchange is cooled in the middle reboiler of the demethanizer and enters the bottom of the first rectification tower DT1; the DT1 rectification tower is divided into two independent parts, upper and lower A and B. The vapor phase of distillation section B is extracted, cooled to -26°C~-30°C with the liquid in the deethanizer tower, and then cooled to -37°C~-38°C with -40°C propylene refrigerant in the feed chiller , into the separator SP2 for separation; the condensate separated from the separator is sent back to the lower B rectification part for reflux; the uncondensed gas enters the upper A rectification part as reboil gas, and the upper rectification A liquid also enters the lower B rectification part The distillation part is used as reflux: in this way, the liquid in the bottom of the first rectification tower through mass transfer and heat transfer enters the demethanizer DA-301, and the top gas phase of the rectification part A in the upper part of the first rectification tower passes through the cold box CD1 and ethylene The refrigerant condenses and enters the vapor-liquid separation tank SP1, the gas phase enters the bottom distillation C part of the second rectification tower DT2, and the liquid phase enters the top A part of the first rectification tower DT1 as reflux;
(2)第二精馏塔DT2下部C精馏的塔顶气相经冷箱CD2换热和乙烯冷剂冷却到-72至-75℃后在分离罐SP3中分离，液体进入下部C精馏部分做回流，气相则进入第二精馏塔上部D精馏部分的塔釜作再沸气。第二精馏塔DT2上部精馏D部分塔顶气相经冷箱CD3换热冷却后在分离罐SP4中分离，液体进入第二精馏塔DT2顶部做回流；(2) The top gas phase of the C rectification in the lower part of the second rectification tower DT2 is cooled to -72 to -75°C by cold box CD2 heat exchange and ethylene refrigerant, and then separated in the separation tank SP3, and the liquid enters the lower C rectification part Do reflux, and the gas phase enters the tower kettle of the rectification part of the upper part of the second rectification tower as reboiling gas. The upper part of the second rectification tower DT2 rectifies the top gas phase of the D part of the tower, which is separated in the separation tank SP4 after heat exchange and cooling by the cold box CD3, and the liquid enters the top of the second rectification tower DT2 for reflux;
(3)第一精馏塔DT1底部出来的液相进入脱甲烷塔DA-301，脱甲烷塔在-72至-75℃操作运行，顶部尾气约有10％-15％的乙烯回收。(3) The liquid phase from the bottom of the first rectification tower DT1 enters the demethanizer DA-301. The demethanizer operates at -72 to -75°C, and about 10%-15% of ethylene is recovered from the top tail gas.
本发明所述第三步的顶部尾气回收方法采用吸收塔AD1进行回收，吸收塔AD1顶部出来的甲烷和氢气，进一步处理得到纯净的氢气产品；脱甲烷塔底部的釜液和解吸塔DA1顶部出来的乙烯进入脱乙烷塔进一步分离C2、C3。The top tail gas recovery method of the third step of the present invention adopts the absorption tower AD1 to reclaim, and the methane and hydrogen that come out from the top of the absorption tower AD1 are further processed to obtain pure hydrogen products; the still liquid at the bottom of the demethanizer and the top of the desorption tower DA1 come out The ethylene in the deethanizer is further separated from C 2 and C 3 .
本流程的特点在于：The characteristics of this process are:
1、应用多级逆流接触精馏塔：1. Application of multi-stage countercurrent contact distillation tower:
(a)把传统脱甲烷工艺中分离罐的一次平衡改成了逆流接触的多次平衡，使重组份乙烯和轻组份甲烷进一步分离；(a) Change the primary balance of the separation tank in the traditional demethanization process to multiple balances of countercurrent contact, so that the heavy component ethylene and light component methane are further separated;
(b)气液在塔中直接接触传热和传质，避免了ARS技术中板翅式换热器换热通道中气液两相流动，有可能使传热效果降低，并且不易控制、操作弹性小等缺点；(b) The gas-liquid directly contacts the heat transfer and mass transfer in the tower, avoiding the gas-liquid two-phase flow in the heat exchange channel of the plate-fin heat exchanger in ARS technology, which may reduce the heat transfer effect, and is not easy to control and operate Disadvantages such as small elasticity;
(c)在精馏塔中，气液接触面积远远大于冷箱中两相接触面积，可得到更好的分离效果。(c) In the rectification tower, the gas-liquid contact area is much larger than the two-phase contact area in the cold box, and better separation effect can be obtained.
2.在脱甲烷塔和冷箱后采用了溶剂吸收工艺。吸收塔的主要作用是回收脱甲烷塔尾气中的乙烯，吸收剂的用量和能耗都很低。通过调节吸收剂的用量，可使乙烯的损失降低到最小，提高了乙烯的收率。采用此工艺，使得70％以上的甲烷和氢气在脱甲烷塔前离开脱甲烷塔，而且塔顶回流温度提高到-75℃，从而减少脱甲烷塔顶冷凝器的热负荷，使冷剂消耗明显下降；2. Solvent absorption process is adopted after demethanizer and cold box. The main function of the absorption tower is to recover ethylene in the tail gas of the demethanizer, and the amount of absorbent and energy consumption are very low. By adjusting the amount of absorbent, the loss of ethylene can be minimized and the yield of ethylene can be increased. With this process, more than 70% of the methane and hydrogen leave the demethanizer before the demethanizer, and the top reflux temperature is increased to -75°C, thereby reducing the heat load of the demethanizer top condenser and significantly consuming refrigerant decline;
3.在预冷阶段，提高了甲烷氢的分离温度，使乙烯冷剂的能量消耗大幅度降低取消了-101℃的乙烯冷剂，使冷剂的需求向较高级别的冷剂转移；由于冷量向较高的级别转移，使耐低温的钢材消耗量减小；3. In the pre-cooling stage, the separation temperature of methane and hydrogen was increased, so that the energy consumption of ethylene refrigerant was greatly reduced, and the ethylene refrigerant at -101°C was canceled, so that the demand for refrigerant was shifted to higher-grade refrigerant; The cooling capacity is transferred to a higher level, so that the consumption of low temperature resistant steel is reduced;
4.此流程由于对脱甲烷塔塔顶乙烯含量不再严格控制，使操作稳定性增强。由于流程对尾气中乙烯含量要求大为降低，脱甲烷塔不再是扩产改造的“瓶颈”，多余的乙烯均可通过高效的吸收塔来完全回收。4. In this process, since the ethylene content at the top of the demethanizer is no longer strictly controlled, the operation stability is enhanced. Since the requirements for the ethylene content in the tail gas are greatly reduced, the demethanizer is no longer the "bottleneck" for production expansion and transformation, and the excess ethylene can be completely recovered through the efficient absorption tower.
本发明的效果在于：Effect of the present invention is:
本发明的方法中精馏塔DT1底部出来的物料进入脱甲烷塔DA-301，由于进料中甲烷氢的含量大幅度降低，使脱甲烷塔的负荷减小，同时降低脱甲烷塔的回流比，脱甲烷塔顶所需冷量降低，节省了乙烯冷剂用量。而且吸收-解吸过程则利用大量的急冷过程中所富余大量的低品位的急冷水。使乙烯过程的能量利用更加合理，大幅度降低乙烯生产能耗。采用本工艺可使目前的700-800Kcal/吨乙烯降低到400-500Kcal/吨乙烯。同时采用本流程可降低原流程的乙烯机、丙烯机负荷各50％和80％左右，可使原流程的生产能力大幅度提高。In the method of the present invention, the material coming out of the bottom of the rectifying tower DT1 enters the demethanizer DA-301. Since the content of methane hydrogen in the feed is greatly reduced, the load of the demethanizer is reduced, and the reflux ratio of the demethanizer is reduced simultaneously. , the cooling capacity required at the top of the demethanizer is reduced, saving the amount of ethylene refrigerant. Moreover, the absorption-desorption process utilizes a large amount of low-grade quenching water surplus in a large amount of quenching process. The energy utilization of the ethylene process is made more reasonable, and the energy consumption of ethylene production is greatly reduced. Adopting this process can reduce the current 700-800Kcal/ton of ethylene to 400-500Kcal/ton of ethylene. At the same time, the adoption of this process can reduce the loads of the ethylene machine and the propylene machine of the original process by about 50% and 80%, respectively, and can greatly increase the production capacity of the original process.
图1为本发明的工艺流程示意图。Fig. 1 is a schematic diagram of the process flow of the present invention.
本发明提出的一种用于乙烯生产中脱甲烷的方法实施例。该工艺流程如图1所示，包括以下步骤：An example of a method for demethanization in ethylene production proposed by the present invention. The process flow shown in Figure 1 includes the following steps:
(1)经过压缩干燥换热后的裂解气，在脱甲烷塔中间再沸器中冷却进入第一精馏塔DT1底部；DT1精馏塔分为上下A、B两个独立的部分，下部精馏段B的汽相采出，用脱乙烷塔釜液冷却至-26℃~-30℃后又在进料激冷器里用-40℃丙烯冷剂冷却到-37℃~-38℃，进入分离器SP2分离；分离器分出的凝液送回下部B精馏部分做回流；未冷凝的气体作为再沸气体进入上部A精馏部分，上部精馏A的液体也进入下部B精馏部分做回流：这样，通过第一精馏塔传质传热的塔釜釜液进入脱甲烷塔DA-301，而第一精馏塔上部精馏A部分的顶部气相经冷箱CD1和乙烯冷剂冷凝，进入汽液分离罐SP1，气相进入第二精馏塔DT2下部精馏C部分的塔釜，液相则进入第一精馏塔DT1顶A部分作为回流：(1) The cracked gas after compression, drying and heat exchange is cooled in the middle reboiler of the demethanizer and enters the bottom of the first rectification tower DT1; the DT1 rectification tower is divided into two independent parts, upper and lower A and B. The vapor phase of distillation section B is extracted, cooled to -26°C~-30°C with the liquid in the deethanizer tower, and then cooled to -37°C~-38°C with -40°C propylene refrigerant in the feed chiller , into the separator SP2 for separation; the condensate separated from the separator is sent back to the lower B rectification part for reflux; the uncondensed gas enters the upper A rectification part as reboil gas, and the upper rectification A liquid also enters the lower B rectification part The distillation part is used as reflux: in this way, the liquid in the bottom of the first rectification tower through mass transfer and heat transfer enters the demethanizer DA-301, and the top gas phase of the rectification part A in the upper part of the first rectification tower passes through the cold box CD1 and ethylene The refrigerant condenses and enters the vapor-liquid separation tank SP1, the gas phase enters the bottom distillation C part of the second rectification tower DT2, and the liquid phase enters the top A part of the first rectification tower DT1 as reflux:
(2)第二精馏塔DT2下部C精馏的塔顶气相经冷箱CD2换热和乙烯冷剂冷却到-72℃后在分离罐SP3中分离，液体进入下部C精馏部分做回流，气相则进入第二精馏塔上部D精馏部分的塔釜作再沸气。第二精馏塔DT2上部精馏D部分塔顶气相经冷箱CD3换热冷却后在分离罐SP4中分离，液体进入第二精馏塔DT2顶部做回流；(2) The top gas phase of the C rectification in the lower part of the second rectification tower DT2 is separated in the separation tank SP3 after heat exchange in the cold box CD2 and ethylene refrigerant to -72 ° C, and the liquid enters the lower C rectification part for reflux, The gas phase then enters the bottom of the rectification part of the upper part of the second rectification tower D as reboiling gas. The upper part of the second rectification tower DT2 rectifies the top gas phase of the D part of the tower, which is separated in the separation tank SP4 after heat exchange and cooling by the cold box CD3, and the liquid enters the top of the second rectification tower DT2 for reflux;
(3)第一精馏塔DT1底部出来的液相进入脱甲烷塔DA-301，脱甲烷塔在-72℃操作运行，顶部尾气约有12％的乙烯进入吸收塔AD1回收；(3) The liquid phase coming out of the bottom of the first rectification tower DT1 enters the demethanizer DA-301, the demethanizer operates at -72°C, and about 12% of the ethylene in the top tail gas enters the absorption tower AD1 for recovery;
(4)吸收塔AD1顶部出来的甲烷和氢气，进入变压吸附系统(PSA)得到纯净的氢气产品。脱甲烷塔底部的釜液和解吸塔DA1顶部出来的乙烯进入乙烷塔进一步分离C2、C3。(4) Methane and hydrogen from the top of the absorption tower AD1 enter the pressure swing adsorption system (PSA) to obtain pure hydrogen products. The still liquid at the bottom of the demethanizer and the ethylene from the top of the desorption tower DA1 enter the ethane tower for further separation of C 2 and C 3 .
针对轻柴油裂解年产三十万吨设计数据应用本流程进行了初步模拟计算。Based on the design data of 300,000 tons of light oil cracking per year, this process is used to carry out preliminary simulation calculations.
上述工艺流程主要参数实施例1如下所示：Above-mentioned technological process main parameter embodiment 1 is as follows:
第一精馏塔：a塔：理论板5块，温度：塔顶-40.6℃ 塔底：-17.1℃The first rectification tower: tower a: 5 theoretical plates, temperature: tower top -40.6°C tower bottom: -17.1°C
b塔：理论板5块，温度：塔顶-72.3℃ 塔底：-71.3℃Column b: 5 theoretical plates, temperature: tower top -72.3°C tower bottom: -71.3°C
第二精馏塔 c塔：理论板5块，温度：塔顶-116.3℃ 塔底：-105.3℃The second rectification tower c tower: 5 theoretical plates, temperature: tower top -116.3°C tower bottom: -105.3°C
d塔：理论板5块，温度：塔顶-130.8℃ 塔底：-130.7℃d Tower: 5 theoretical plates, temperature: tower top -130.8°C tower bottom: -130.7°C
脱甲烷塔理论板：43 温度：塔顶-76.1℃ 塔底：7.1℃Demethanizer theoretical plate: 43 Temperature: Tower top -76.1°C Tower bottom: 7.1°C
吸收塔理论板： 15 温度：塔顶-30℃ 塔底：-31.2℃Theoretical plate of absorption tower: 15 Temperature: Tower top -30°C Tower bottom: -31.2°C
溶剂的用量2吨溶剂/吨乙烯The amount of solvent used is 2 tons of solvent/ton of ethylene
解析塔理论板：15 温度：塔顶15℃ 塔底：5℃Analytical tower theoretical plate: 15 Temperature: Tower top 15°C Tower bottom: 5°C
该工艺中裂解气进脱甲烷塔之前已将80％以上的氢气、甲烷分离出来。进料中的氢气、甲烷含量仅分别为0.8％及10％左右，因而大大降低了脱甲烷塔的负荷。In this process, more than 80% of the hydrogen and methane have been separated before the cracked gas enters the demethanizer. The hydrogen and methane contents in the feed are only about 0.8% and 10% respectively, thus greatly reducing the load of the demethanizer.
同时新工艺中脱甲烷预冷段用精馏塔代替一次分离的气液接触，使冷的液相物流和热的气相物流经过充分的传质和传热，使甲烷一氢等轻组份和乙烯等重组份得到进一步分离，使进入脱甲烷塔的甲烷量大幅度降低。由于第一精馏塔下部精馏段提前脱除了重组份，使进入预冷段的流量降低，同时也降低了能量消耗，节省能量约30％左右。在相同的能量损失情况下，其中可节约乙烯制冷剂30％左右，丙烯冷剂35％左右。At the same time, in the demethanization precooling section of the new process, a rectification tower is used instead of a separate gas-liquid contact, so that the cold liquid phase stream and the hot gas phase stream undergo sufficient mass transfer and heat transfer, so that light components such as methane-hydrogen and Heavy components such as ethylene are further separated, so that the amount of methane entering the demethanizer is greatly reduced. Since the heavy components are removed in advance in the lower rectification section of the first rectification tower, the flow rate entering the precooling section is reduced, and energy consumption is also reduced, saving about 30% of energy. In the case of the same energy loss, about 30% of the ethylene refrigerant and about 35% of the propylene refrigerant can be saved.
上述工艺流程主要参数实施例2如下所示：Above-mentioned technological process main parameter embodiment 2 is as follows:
第一精馏塔：a塔：理论板 6块，温度：塔顶-40.6℃ 塔底：-17.1℃The first rectification tower: tower a: 6 theoretical plates, temperature: tower top -40.6°C tower bottom: -17.1°C
b塔：理论板 6块，温度：塔顶-72.3℃ 塔底：-71.3℃Column b: 6 theoretical plates, temperature: tower top -72.3°C tower bottom: -71.3°C
第二精馏塔 c塔：理论板 6块，温度：塔顶-116.3℃ 塔底：-105.3℃The second rectification tower c tower: 6 theoretical plates, temperature: tower top -116.3°C tower bottom: -105.3°C
d塔：理论板 6块，温度：塔顶-130.8℃ 塔底：-130.7℃Column d: 6 theoretical plates, temperature: tower top -130.8°C tower bottom: -130.7°C
脱甲烷塔 理论板：43温度：塔顶-76.1℃ 塔底：7.1℃Demethanizer Theoretical plate: 43 Temperature: Tower top -76.1°C Tower bottom: 7.1°C
吸收塔理论板：15 温度：塔顶-30 塔底：-31.2℃Theoretical plate of absorption tower: 15 Temperature: Tower top -30 Tower bottom: -31.2℃
溶剂的用量3吨溶剂/吨乙烯The amount of solvent used is 3 tons of solvent/ton of ethylene
解析塔理论板：15温度：塔顶 15℃ 塔底：5℃Theoretical plate of analytical tower: 15°C Temperature: Tower top 15°C Tower bottom: 5°C
裂解气进脱甲烷塔之前可将81％以上的氢气、甲烷分离出来。进料中的氢气、甲烷含量仅分别为0.75％及9％左右。节省能量约30.5％左右。在相同的能量损失情况下，其中可节约乙烯制冷剂31％，丙烯冷剂35.5％。Before the cracked gas enters the demethanizer, more than 81% of hydrogen and methane can be separated. The hydrogen and methane contents in the feed are only about 0.75% and 9% respectively. Save energy about 30.5%. In the case of the same energy loss, 31% of ethylene refrigerant and 35.5% of propylene refrigerant can be saved.
上述工艺流程主要参数实施例3如下所示：Above-mentioned technological process main parameter embodiment 3 is as follows:
第一精馏塔：a塔：理论板 6块，温度：塔顶-40.6℃ 塔底：-17.1℃The first rectification tower: tower a: 6 theoretical plates, temperature: tower top -40.6°C tower bottom: -17.1°C
b塔：理论板 6块，温度：塔顶-72.3℃ 塔底：-71.3℃Column b: 6 theoretical plates, temperature: tower top -72.3°C tower bottom: -71.3°C
第二精馏塔 c塔：理论板 6块，温度：塔顶-116.3℃ 塔底：-105.3℃The second rectification tower c tower: 6 theoretical plates, temperature: tower top -116.3°C tower bottom: -105.3°C
d塔：理论板 6块，温度：塔顶-130.8℃ 塔底：-130.7℃Column d: 6 theoretical plates, temperature: tower top -130.8°C tower bottom: -130.7°C
脱甲烷塔 理论板：50温度：塔顶-76.1℃ 塔底：7.1℃Demethanizer Theoretical plate: 50°C Temperature: Tower top -76.1°C Tower bottom: 7.1°C
吸收塔理论板： 20温度：塔顶-30℃ 塔底：-31.2℃Theoretical plate of absorption tower: 20 Temperature: Tower top -30°C Tower bottom: -31.2°C
溶剂的用量3吨溶剂/吨乙烯The amount of solvent used is 3 tons of solvent/ton of ethylene
解析塔理论板：20温度：塔顶 15℃ 塔底：5℃Analytical tower theoretical plate: 20 Temperature: Tower top 15°C Tower bottom: 5°C
裂解气进脱甲烷塔之前可将80.5％以上的氢气、甲烷分离出来。进料中的氢气、甲烷含量仅分别为0.82％及9.1％左右。节省能量约31％左右。在相同的能量损失情况下，其中可节约乙烯制冷剂29％，丙烯冷剂34％。Before the cracked gas enters the demethanizer, more than 80.5% of hydrogen and methane can be separated. The hydrogen and methane contents in the feed are only about 0.82% and 9.1% respectively. The energy saving is about 31%. In the case of the same energy loss, 29% of ethylene refrigerant and 34% of propylene refrigerant can be saved.
Claims (2)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB011183594A CN1188375C (en) | 2001-05-25 | 2001-05-25 | Method for demethanizing in ethylene production |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB011183594A CN1188375C (en) | 2001-05-25 | 2001-05-25 | Method for demethanizing in ethylene production |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1326913A CN1326913A (en) | 2001-12-19 |
| CN1188375C true CN1188375C (en) | 2005-02-09 |
Family
ID=4663130
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB011183594A Expired - Fee Related CN1188375C (en) | 2001-05-25 | 2001-05-25 | Method for demethanizing in ethylene production |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1188375C (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2020069246A1 (en) * | 2018-09-28 | 2020-04-02 | Uop Llc | Pressure swing adsorption integration in steam cracking ethylene plants |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8209996B2 (en) * | 2003-10-30 | 2012-07-03 | Fluor Technologies Corporation | Flexible NGL process and methods |
| CN100404483C (en) * | 2005-09-23 | 2008-07-23 | 中国石油大学(北京) | Hydration + Pressure Swing Adsorption + Cryogenic Combined Process for Separation of Ethylene Cracking Gas |
| CN100430351C (en) * | 2005-09-23 | 2008-11-05 | 中国石油大学(北京) | Combined process of secondary hydration + cryogenic separation for separation of ethylene cracking gas |
| CN100404482C (en) * | 2005-09-23 | 2008-07-23 | 中国石油大学(北京) | Combined process of hydration + membrane + cryogenic separation for separation of ethylene cracking gas |
| CN109867579B (en) * | 2017-12-01 | 2021-11-16 | 中国石化工程建设有限公司 | Device and method for improving start-up operation of demethanizer of ethylene plant |
| US11231227B2 (en) | 2017-12-15 | 2022-01-25 | Saudi Arabian Oil Company | Process integration for natural gas liquid recovery |
-
2001
- 2001-05-25 CN CNB011183594A patent/CN1188375C/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2020069246A1 (en) * | 2018-09-28 | 2020-04-02 | Uop Llc | Pressure swing adsorption integration in steam cracking ethylene plants |
Also Published As
| Publication number | Publication date |
|---|---|
| CN1326913A (en) | 2001-12-19 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN108610229B (en) | Light hydrocarbon separation system and method | |
| WO2016197487A1 (en) | Three-tower device and method for recycling ethylene and ethane from dry gas through oil absorption | |
| CN112028731B (en) | Method for separating propylene reaction product from propane dehydrogenation | |
| CN105783421B (en) | A kind of method and device of natural gas lighter hydrocarbons recovery | |
| WO2007036156A1 (en) | A process for recovering lower carbon olefins from product gas for production of olefins | |
| CN1727317A (en) | Secondary Deethanizer to Eliminate Bottlenecks in Ethylene Plants | |
| KR0144699B1 (en) | Process for recovering ethylene comprising precooling step | |
| CN112939724B (en) | Recovery device and recovery process for reaction product of propane dehydrogenation propylene preparation | |
| CN1188375C (en) | Method for demethanizing in ethylene production | |
| CN1407304A (en) | Improved light hydrocarbon deep cooling separating method | |
| CN111320523B (en) | Method and device for separating ethylene from refinery dry gas | |
| CN113121301A (en) | Recovery method of light hydrocarbon in refinery dry gas | |
| CN113354501B (en) | A separation method for recovering C1, C2 and C3 in catalytic rich gas by a combined absorption method | |
| CN110407658B (en) | Low-energy-consumption cryogenic separation process method for ethane pyrolysis gas | |
| CN110108091B (en) | Cryogenic liquefaction system with improved hydrogen separation membrane insertion for STAR propane dehydrogenation | |
| CN111320522B (en) | Method and device for separating ethylene from refinery dry gas | |
| KR20030094247A (en) | Advanced heat integrated rectifier system | |
| CN215517292U (en) | Integrated process system for producing LNG (liquefied Natural gas) and LPG (liquefied Petroleum gas) from oilfield associated gas | |
| CN115948188A (en) | System and method for recovering ethane from natural gas | |
| CN111393250A (en) | Light hydrocarbon separation device and method | |
| JP3730362B2 (en) | Method for separating hydrogen and methane from gaseous hydrocarbons | |
| CN112760134B (en) | Oil gas recovery method and device | |
| CN104211554B (en) | A kind of system and method for recovered ethylene from MTO/DTO gas product | |
| CN113350974B (en) | A kind of separation and recovery method of H2, C1, C2 and C3 in saturated dry gas | |
| JPH0543691B2 (en) |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C19 | Lapse of patent right due to non-payment of the annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |