CN103666585A - Coupling method and system of low-temperature methanol washing process and CO2 compression process - Google Patents

Abstract

Translated fromChinese

本发明公开了一种低温甲醇洗工艺和CO₂压缩工艺的耦合方法及系统，低温甲醇洗工艺中的CO₂解吸塔底与H₂S浓缩塔之间设有CO₂闪蒸塔，CO₂压缩工艺具有CO₂多级压缩装置和泵提压装置，所述耦合方法包括以下步骤：将所述CO₂解吸塔塔底的甲醇富液和所述CO₂多级压缩装置末端的压缩CO₂产品气通过一个换热器进行耦合，耦合后的甲醇富液送入所述CO₂闪蒸塔，耦合后的压缩CO₂产品气降温液化成为液化CO₂产品，再由泵提压装置提压输送。本发明将CO₂压缩过程产生热量再利用，用于提供低温甲醇洗流程中强化CO₂解吸的甲醇富液温升热源，同时利用CO₂解吸塔底甲醇富液的冷量，节省压缩过程制冷电耗，提高能量利用率。

The invention discloses a coupling method and system of a low-temperature methanol washing process and a CO₂ compression process. In the low-temperature methanol washing process, a CO₂ flash tower is arranged between the bottom of the CO₂ desorption tower and the H₂ S concentration tower, and the CO₂ The compression process has a_CO2 multistage compression device and a pump pressure lifting device, and the coupling method includes the following steps: the methanol-rich liquid at the bottom of the_CO2 desorption tower and the compressed_CO2 at the end of the_CO2 multistage compression device The product gas is coupled through a heat exchanger, and the coupled methanol-rich liquid is sent to the CO₂ flash tower, and the coupled compressed CO₂ product gas is cooled and liquefied into a liquefied CO₂ product, and then the pressure is raised by the pump pressure device delivery. The invention reuses the heat generated in the_CO2 compression process to provide a heat source for the temperature rise of the methanol_- rich liquid that strengthens CO2 desorption in the low-temperature methanol washing process, and at the same time utilizes the cooling capacity of the methanol-rich liquid at the bottom of the_CO2 desorption tower to save refrigeration in the compression process Reduce power consumption and improve energy utilization.

Description

Translated fromChinese

一种低温甲醇洗工艺和CO2压缩工艺的耦合方法及系统Coupling method and system of low-temperature methanol washing process and CO2 compression process

技术领域technical field

本发明涉及气体净化领域及温室气体减排领域，具体涉及一种低温甲醇洗工艺和CO₂压缩工艺的耦合方法及系统。The invention relates to the field of gas purification and the field of greenhouse gas emission reduction, in particular to a coupling method and system of a low-temperature methanol washing process and a_CO2 compression process.

背景技术Background technique

CO₂的排放总量在过去100年中大幅增长，导致全球的平均气温明显上升，温室效应已经成为21世纪人类面临的最严峻的环境问题之一。将煤、石油等矿物燃料利用过程中产生并排放的CO₂进行分离与回收，封存及利用（CCS&CCUS）已经引起世界各国的普遍重视。The total amount of CO₂ emissions has increased significantly in the past 100 years, leading to a significant increase in the global average temperature, and the greenhouse effect has become one of the most serious environmental problems facing mankind in the 21st century. The separation and recovery, storage and utilization (CCS&CCUS) of CO₂ produced and emitted during the utilization of coal, petroleum and other fossil fuels has attracted widespread attention from all over the world.

以煤气化为龙头的现代煤化工技术已经成为煤炭清洁利用的一个重要方向，具有煤的热利用效率高，操作费用低，粉尘、NO_x、SO₂等污染物接近零排放的特点。现代煤气化过程具有不仅原料来源广，热利用效率高，同时可以实现燃烧前CO₂的脱除及捕集，以较低的能耗和经济成本实现CO₂的减排。在未来的CO₂减排过程中，煤气化与燃烧前CO₂捕集技术的结合将具有广泛的应用。The modern coal chemical technology led by coal gasification has become an important direction for clean coal utilization. It has the characteristics of high thermal utilization efficiency of coal, low operating cost, and close to zero emission of dust, NO_x , SO₂ and other pollutants. The modern coal gasification process not only has a wide source of raw materials and high heat utilization efficiency, but also can remove and capture CO₂ before combustion, and achieve CO₂ emission reduction with low energy consumption and economic cost. In the future_CO2 emission reduction process, the combination of coal gasification and pre-combustion_CO2 capture technology will have a wide range of applications.

低温甲醇洗工艺是一种成熟商业化应用的CO₂、H₂S气体脱除技术，也是极具代表性的燃烧前CO₂分离技术。利用甲醇在低温条件下对酸性气体溶解度大的物理特性，可以有效的从粗合成气中脱除H₂S、CO₂等酸性气体，使合成气达到很高的净化度。The low-temperature methanol washing process is a mature and commercially applied CO₂ and H₂ S gas removal technology, and it is also a very representative pre-combustion CO₂ separation technology. Utilizing the physical characteristics of methanol's high solubility to acid gases under low temperature conditions, it can effectively remove acid gases such as H₂ S and CO₂ from crude synthesis gas, so that the synthesis gas can reach a high degree of purification.

在以煤为原料，气化工艺采用激冷流程的工艺过程之后，低温甲醇洗可以有效的同时脱除粗变换气中的CO₂和H₂S等杂质。低温甲醇洗气体净化工艺，在得到净化合成气的同时，能够副产品气：富H₂S产品气和CO₂产品气。高浓度CO₂产品气在工艺中的回收率一般60%左右。剩余CO₂大部分在排放尾气中，浓度大致为60～85%，这部分CO₂因浓度较低，得到高浓度CO₂的能耗及费用高，多数处理方式为直接排空。还有少量CO₂在富H₂S产品气，随产品气进入克劳斯硫回收过程。After coal is used as raw material and the gasification process adopts a chilling process, low-temperature methanol washing can effectively remove impurities such as CO₂ and H₂ S in the crude shift gas at the same time. The low-temperature methanol scrubbing gas purification process, while obtaining purified synthesis gas, can produce by-product gases: H₂ S-rich product gas and CO₂ product gas. The recovery rate of high-concentration CO₂ product gas in the process is generally about 60%. Most of the remaining CO₂ is in the tail gas, with a concentration of approximately 60-85%. Due to the low concentration of this part of CO₂ , the energy consumption and cost of obtaining high-concentration CO₂ are high. Most of the treatment methods are direct emptying. There is also a small amount of CO₂ in the H₂ S-rich product gas, which enters the Claus sulfur recovery process with the product gas.

工艺产生的高浓度CO₂产品气进行入管输送前需进行压缩处理。CO₂产品气的压缩工段可分两步进行：首先用压缩机将CO₂气体压缩为具有一定压力的液态，然后利用泵来进一步将其提压至规定的压力值。工程中常将（60bar，23℃）作为泵和压缩机工作区间的分界点，低于60bar时采用压缩机压缩，高于60bar后采用泵来压缩。经过压缩机压缩后，CO₂温度会超过23℃，为了确保通过泵时的CO₂处于液态，必须对CO₂进行冷却处理，使其温度不超过23℃。The high-concentration CO₂ product gas produced by the process needs to be compressed before being transported into the pipeline. The compression section of_CO2 product gas can be divided into two steps: first, the compressor is used to compress the_CO2 gas into a liquid state with a certain pressure, and then the pump is used to further increase the pressure to the specified pressure value. In engineering, (60bar, 23°C) is often used as the dividing point between the working range of the pump and the compressor. When it is lower than 60bar, the compressor is used for compression, and when it is higher than 60bar, the pump is used for compression. After being compressed by the compressor, the temperature of_CO2 will exceed 23°C. In order to ensure that the_CO2 is in a liquid state when passing through the pump, the_CO2 must be cooled so that its temperature does not exceed 23°C.

出于对管道安全、可靠运行及可比经济性的考虑，CO₂管道输送设计和操作的压力约在8.27-17.23MPa范围内，温度范围从地表温度至最高约48.9℃。这样的设计与操作条件下可以使高纯度的CO₂产品气保持稳定的超临界或致密相态下，从而消除了潜在的两相运输的不稳定性。表1为大量CO₂产品气管道输送要求。低温甲醇洗捕集系统所捕集的CO₂能够满足以上要求，无需进一步净化。这种浓度的CO₂可以用于地质封存或者强化石油开采。For the consideration of pipeline safety, reliable operation and comparable economy, the pressure of CO₂ pipeline design and operation is in the range of 8.27-17.23MPa, and the temperature range is from the surface temperature to the highest of about 48.9°C. Such design and operating conditions can keep the high-purity_CO2 product gas in a stable supercritical or dense phase state, thereby eliminating the potential instability of two-phase transport. Table 1 shows the pipeline transportation requirements for bulk_CO2 product gas. The CO₂ captured by the low-temperature methanol washing capture system can meet the above requirements without further purification. This concentration of_CO2 could be used for geological storage or enhanced oil recovery.

表1典型的CO₂管道输送要求Table 1 Typical_CO2 Pipeline Delivery Requirements

申请号为201310247525.0的发明专利申请中公开了一种高CO₂收率的低温甲醇洗方法及装置，如图1所示。在CO₂解吸塔底与H₂S浓缩塔之间增加CO₂闪蒸塔，通过对CO₂解吸塔底的甲醇富液的升温、降压强化达到CO₂强化解吸，具有提高CO₂产品收率的效果，其CO₂产品气收率可以有效提高至91.2%。工艺中得到的高收率的CO₂产品气通过多级间接冷却压缩，得到液化CO₂产品，用于化工生产、强化石油开采或地质封存。但上述技术中存在以下不足：The invention patent application with application number 201310247525.0 discloses a low-temperature methanol washing method and device with high_CO2 yield, as shown in Figure 1. A CO₂ flash tower is added between the bottom of the CO₂ desorption tower and the H₂ S concentration tower, and the CO₂ enhanced desorption can be achieved by increasing the temperature and depressurization of the methanol-rich liquid at the bottom of the CO₂ desorption tower, which can improve the CO₂ product absorption. The effect of efficiency, the CO₂ product gas yield can be effectively increased to 91.2%. The high-yield_CO2 product gas obtained in the process is compressed through multi-stage indirect cooling to obtain liquefied_CO2 products for chemical production, enhanced oil recovery or geological storage. But there is following deficiency in above-mentioned technology:

（1）提高CO₂产品气收率，通过额外热量供给使甲醇富液升温。随着捕集率的提高，工艺中需增加额外热量输入大量增加。(1) Increase the yield of CO₂ product gas, and increase the temperature of methanol-rich liquid through additional heat supply. As the capture rate increases, the need for additional heat input to the process increases substantially.

（2）提高CO₂产品气收率，通过额外冷量供给使CO₂闪蒸塔顶的富CO₂压缩气降温回送到CO₂解吸塔底。随着捕集率的提高，工艺中需增加额外冷量输入增加。(2) To increase the CO₂ product gas yield, the CO₂ rich compressed gas at the top of the CO₂ flash tower is cooled and returned to the bottom of the CO₂ desorption tower through additional cooling supply. As the capture rate increases, the additional cooling input required in the process increases.

（3）CO₂压缩过程需要一定的冷量输入，并且随着CO₂产品气的增加，冷却处理的电力消耗会大量增加。(3) The_CO2 compression process requires a certain amount of cooling input, and with the increase of the_CO2 product gas, the power consumption of the cooling process will increase significantly.

（4）CO₂强化解吸过程和CO₂压缩过程存在能量利用不合理，存在工艺能耗过高的问题。(4) The CO₂ enhanced desorption process and the CO₂ compression process have unreasonable energy utilization and high process energy consumption.

发明内容Contents of the invention

本发明的目的在于解决上述一种高CO₂收率的低温甲醇洗工艺在提高CO₂收率时能量利用不合理、工艺能耗过高的工艺问题，提供一种低温甲醇洗工艺和CO₂压缩工艺的耦合方法及系统，该方法和系统能够在高CO₂产品气的收率条件下，合理利用系统中的冷量和CO₂压缩过程中的热量，降低高CO₂捕集率下的系统能耗，减少操作成本。The purpose of the present invention is to solve the process problems of unreasonable energy utilization and high energy consumption of the above-mentioned low-temperature methanol washing process with high_CO2 yield when increasing the_CO2 yield, and provide a low-temperature methanol washing process and_CO2 A coupling method and system for compression process, the method and system can rationally utilize the cooling capacity in the system and the heat in the_CO2 compression process under the condition of high_CO2 product gas yield, and reduce the_CO2 capture rate under high System energy consumption reduces operating costs.

本发明解决上述技术问题的技术方案是：The technical scheme that the present invention solves the problems of the technologies described above is:

一种低温甲醇洗工艺和CO₂压缩工艺的耦合方法，其中，低温甲醇洗工艺中的CO₂解吸塔底与H₂S浓缩塔之间设有CO₂闪蒸塔，CO₂压缩工艺具有CO₂多级压缩装置和泵提压装置，该耦合方法包括以下步骤：A coupling method of a low-temperature methanol washing process and a_CO2 compression process, wherein a_CO2 flash tower is provided between the bottom of the CO2 desorption tower in the low-temperature methanol washing process and the_H2S concentration tower, and_theCO2 compression process has a CO2₂ multi-stage compression device and pump pressure lifting device, the coupling method includes the following steps:

将所述CO₂解吸塔塔底的甲醇富液和所述CO₂多级压缩装置末端的压缩CO₂产品气通过一个换热器进行耦合，耦合后的甲醇富液送入所述CO₂闪蒸塔，耦合后的压缩CO₂产品气降温液化成为液化CO₂产品由泵提压装置提压至管道输送压力进行输送。Coupling the methanol-rich liquid at the bottom of the_CO2 desorption tower and the compressed_CO2 product gas at the end of the_CO2 multi-stage compression device through a heat exchanger, the coupled methanol-rich liquid is sent to the_CO2 flash In the distillation tower, the coupled compressed CO₂ product gas is cooled and liquefied into a liquefied CO₂ product, which is boosted by the pump pressure device to the pipeline delivery pressure for delivery.

本发明的耦合方法的一个优选方案，其中，当所述低温甲醇洗工艺中CO₂收率为60.4%～79%时，该耦合方法包括以下步骤:A preferred version of the coupling method of the present invention, wherein, when the_CO2 yield is 60.4% to 79% in the low-temperature methanol washing process, the coupling method comprises the following steps:

（1）低温甲醇洗工艺中再生产生的甲醇贫液与H₂S浓缩塔塔底的甲醇富液以及CO₂解吸塔塔底的甲醇富液分别进行热交换降温后输送至酸性气体吸收塔塔顶；(1) The lean methanol solution generated in the low-temperature methanol washing process is exchanged with the methanol-rich solution at the bottom of the H₂ S concentration tower and the methanol-rich solution at the bottom of the CO₂ desorption tower, respectively, and then transported to the acid gas absorption tower top;

（2）CO₂解吸塔塔底的甲醇富液与甲醇贫液热交换升温后，再与CO₂闪蒸塔塔顶的富CO₂气进行热交换升温，然后与CO₂多级压缩装置末端的压缩CO₂产品气通过换热器进行耦合升温，最后送入所述CO₂闪蒸塔。(2) After the methanol-rich liquid at the bottom of the CO₂ desorption tower is heated up by heat exchange with the methanol-poor liquid, it is then heated up by heat exchange with the CO_2- rich gas at the top of theCO 2 flash tower, and then heated up with the end of the CO₂ multi-stage compression device The compressed_CO2 product gas is coupled and heated through a heat exchanger, and finally sent to the_CO2 flash tower.

本发明的耦合方法的一个优选方案，其中，当所述低温甲醇洗工艺中CO₂收率为80%～91.2%时，该耦合方法包括以下步骤:A preferred version of the coupling method of the present invention, wherein, when the_CO2 yield is 80% to 91.2% in the low-temperature methanol washing process, the coupling method comprises the following steps:

（1）低温甲醇洗工艺中再生产生的甲醇贫液与H₂S浓缩塔塔底的甲醇富液以及CO₂解吸塔塔底的甲醇富液分别进行热交换降温后输送至酸性气体吸收塔塔顶；(1) The lean methanol solution generated in the low-temperature methanol washing process is exchanged with the methanol-rich solution at the bottom of the H₂ S concentration tower and the methanol-rich solution at the bottom of the CO₂ desorption tower, respectively, and then transported to the acid gas absorption tower top;

（2）CO₂解吸塔塔底的甲醇富液与甲醇贫液热交换升温后，再与CO₂多级压缩装置末端的压缩CO₂产品气通过一个换热器进行耦合升温，然后与CO₂多级压缩装置中的循环水热端进行热交换升温，最后送入所述CO₂闪蒸塔。(2) After the methanol-rich liquid at the bottom of the CO₂ desorption tower is heat-exchanged with the methanol-lean liquid to raise the temperature, it is coupled with the compressed CO₂ product gas at the end of the CO₂ multi-stage compression device through a heat exchanger to raise the temperature, and then with CO₂ The hot end of the circulating water in the multi-stage compression device is subjected to heat exchange to raise the temperature, and finally sent to the CO₂ flash tower.

本发明的耦合方法的一个优选方案，其中，当所述低温甲醇洗工艺中CO₂收率为60.4%～79%时，CO₂解吸塔塔底的甲醇富液与甲醇贫液热交换升温后，操作温度为-33～-31℃；再与CO₂闪蒸塔塔顶的富CO₂气进行热交换升温后，操作温度为-31～-28℃；再与CO₂多级压缩装置末端的压缩CO₂产品气通过一个换热器进行耦合升温后，操作温度为-26～-6℃。A preferred version of the coupling method of the present invention, wherein, when the_CO2 yield in the low-temperature methanol washing process is 60.4% to 79%, the methanol-rich liquid at the bottom of the_CO2 desorption tower and the methanol-poor liquid heat exchange and heat up , the operating temperature is -33～-31℃; after heat exchange with the CO2_- rich gas at the top of the_CO2 flash tower, the operating temperature is -31～-28℃; and then with the end of the_CO2 multistage compression device After the compressed CO₂ product gas is coupled and heated through a heat exchanger, the operating temperature is -26~-6°C.

本发明的耦合方法的一个优选方案，其中，当所述低温甲醇洗工艺中CO₂收率为80%～91.2%时，CO₂解吸塔塔底的甲醇富液与甲醇贫液热交换升温后，操作温度为-24～0℃；再与CO₂多级压缩装置末端的压缩CO₂产品气通过一个换热器进行耦合升温后，操作温度为-6～18℃；再与CO₂多级压缩装置中的循环水热端进行热交换升温后，操作温度为-6～35℃。A preferred version of the coupling method of the present invention, wherein, when the_CO2 yield in the low-temperature methanol washing process is 80% to 91.2%, the methanol-rich liquid at the bottom of the_CO2 desorption tower and the methanol-poor liquid heat exchange after heating , the operating temperature is -24～0℃; then coupled with the compressed CO₂ product gas at the end of the CO₂ multistage compression device through a heat exchanger, the operating temperature is -6～18℃; then combined with the CO₂ multistage The operating temperature of the circulating water hot end in the compression device is -6 to 35°C after heat exchange to raise the temperature.

一种低温甲醇洗工艺和CO₂压缩工艺的耦合系统，其中，低温甲醇洗工艺中的CO₂解吸塔底与H₂S浓缩塔之间设有CO₂闪蒸塔，CO₂压缩工艺具有CO₂多级压缩装置和泵提压装置，所述CO₂解吸塔塔底通过管道连接于第一换热器后再与所述CO₂闪蒸塔连接，所述CO₂多级压缩装置末端通过管道连接于所述第一换热器后再与泵提压装置连接。A coupling system of low-temperature methanol washing process and_CO2 compression process, wherein a_CO2 flash tower is set between the bottom of the CO2 desorption tower and the_H2S concentration tower in the low-temperature methanol washing process, and_theCO2 compression process has a CO₂ multi-stage compression device and pump pressure-lifting device, the bottom of the_CO2 desorption tower is connected to the first heat exchanger through a pipeline and then connected to the_CO2 flash tower, and the end of the_CO2 multi-stage compression device is passed The pipeline is connected to the first heat exchanger and then connected to the pump pressure raising device.

本发明的耦合系统的一个优选方案，其中，所述CO₂多级压缩装置包括具有多级压缩汽缸的压缩机和多个换热器，所述每级压缩汽缸外设置有换热器，每个换热器分别与进水管和出水管连接。A preferred solution of the coupling system of the present invention, wherein the_CO2 multi-stage compression device includes a compressor with a multi-stage compression cylinder and multiple heat exchangers, and a heat exchanger is arranged outside each compression cylinder, and each The heat exchangers are respectively connected to the water inlet pipe and the water outlet pipe.

本发明的耦合系统的一个优选方案，其中，所述低温甲醇洗工艺中再生产生的甲醇贫液的输送管分别与H₂S浓缩塔塔底连接在第二换热器上、与CO₂解吸塔塔底连接在第三换热器上；A preferred solution of the coupling system of the present invention, wherein, the delivery pipes of the methanol lean liquid regenerated in the low-temperature methanol washing process are respectively connected to the bottom of the_H2S concentration tower on the second heat exchanger, desorbed with_CO2 The bottom of the tower is connected to the third heat exchanger;

所述CO₂解吸塔塔底通过管道连接于所述第三换热器上后，再与CO₂闪蒸塔塔顶连接于第四换热器上，然后与所述第一换热器连接，最后与所述CO₂闪蒸塔连接。After the bottom of the_CO desorption tower is connected to the third heat exchanger through a pipeline, it is connected with the top of the_CO flash tower to the fourth heat exchanger, and then connected to the first heat exchanger , and finally connected with the CO₂ flash tower.

本发明的耦合系统的一个优选方案，其中，所述低温甲醇洗工艺中再生产生的甲醇贫液的输送管分别与H₂S浓缩塔塔底连接在第二换热器上、与CO₂解吸塔塔底连接在第三换热器上；A preferred solution of the coupling system of the present invention, wherein, the delivery pipes of the methanol lean liquid regenerated in the low-temperature methanol washing process are respectively connected to the bottom of the_H2S concentration tower on the second heat exchanger, desorbed with_CO2 The bottom of the tower is connected to the third heat exchanger;

所述CO₂解吸塔塔底通过管道连接于所述第三换热器上后，再与所述第一换热器连接，然后与所述出水管连接在第五换热器上，最后与所述CO₂闪蒸塔连接。The_CO desorption tower bottom is connected to the third heat exchanger through a pipeline, then connected to the first heat exchanger, then connected to the fifth heat exchanger with the water outlet pipe, and finally connected to the fifth heat exchanger. The_CO2 flash column is connected.

本发明与现有技术相比具有以下的有益效果：Compared with the prior art, the present invention has the following beneficial effects:

在低温甲醇洗工艺中，为了提高CO₂产品收率，在CO₂解吸塔底与H₂S浓缩塔之间增加CO₂闪蒸塔，CO₂解吸塔底的低温甲醇富液需经过升温、降压后再进入CO₂闪蒸塔进行强化解吸；而在CO₂压缩工艺中，CO₂气体经过多次压缩后，需要冷却到一定的温度才便于后续的泵送；本发明巧妙地利用上述两个工艺过程中一个需要升温、一个需要冷却的特点，将两者耦合在一起，实现能量的相互利用，使得两个工艺中的上述处理过程无需再由外部单独提供热量或冷量，节省了电耗，提高了整体系统的能量利用率。In the low-temperature methanol washing process, in order to increase the yield of_CO2 products, a_CO2 flash tower is added between the bottom of the_CO2 desorption tower and the_H2S concentration tower, and the low-temperature methanol-rich liquid at the bottom of the_CO2 desorption tower needs to be heated, After depressurization, enter the_CO2 flash tower for enhanced desorption; while in the_CO2 compression process,_CO2 gas needs to be cooled to a certain temperature to facilitate subsequent pumping after multiple compressions; the present invention cleverly utilizes the above One of the two processes needs to be heated and the other needs to be cooled. The two processes are coupled together to realize the mutual utilization of energy, so that the above-mentioned processes in the two processes do not need to be provided with heat or cooling separately from the outside, saving Power consumption improves the energy utilization rate of the overall system.

附图说明Description of drawings

图1为现有技术中的一种高CO₂收率的低温甲醇洗工艺流程图，其中：4吸收塔；14CO₂解吸塔；19H₂S浓缩塔；28甲醇热再生塔；43甲醇精馏塔，50CO₂闪蒸塔；3、11、12、13、30、33为闪蒸塔；2、8、9、10、25、27、29、32、36、42、46、49、53为换热器；26、31、38、41、55为泵；43、52压缩机；1、5、6、7、15、16、17、18、20、22、23、34、35、37、39、40、44、45、47、48、51、54为物料编号。Fig. 1 is a kind of high CO in the prior art Low_- temperature methanol washing process flow chart of yield, wherein: 4 absorption towers;_14CO Desorption towers;_19H S concentration towers; 28 methanol heat regeneration towers; 43 methanol rectification tower, 50CO₂ flash tower; 3, 11, 12, 13, 30, 33 are flash towers; Heat exchanger; 26, 31, 38, 41, 55 are pumps; 43, 52 compressors; 1, 5, 6, 7, 15, 16, 17, 18, 20, 22, 23, 34, 35, 37, 39, 40, 44, 45, 47, 48, 51, 54 are the material numbers.

图2为本发明的低温甲醇洗工艺和CO₂压缩工艺的耦合方系统中，当CO₂收率为60.4%～78%时的系统示意图；其中：56、60、62、63、64、65为换热器，61为多级压缩机，68为泵，70循环水冷端，71为循环水热端，66为压缩CO₂产品气，67、69为液化CO₂产品；其余零件编号与图1中的相同零件编号表示相同的部件或物料；并且，在换热器中，60为第一换热器，27为第二换热器，56为第三换热器，53为第四换热器。Fig. 2 is the low-temperature methanol washing process of the present invention and_CO Compression process in the coupling system, when_CO The yield is 60.4% ~ 78% of the system diagram; wherein: 56, 60, 62, 63, 64, 65 61 is a multi-stage compressor, 68 is a pump, 70 is a circulating water cooling end, 71 is a circulating water heating end, 66 is a compressed CO₂ product gas, 67, 69 are a liquefied CO₂ product; The same part numbers in 1 represent the same parts or materials; and, among the heat exchangers, 60 is the first heat exchanger, 27 is the second heat exchanger, 56 is the third heat exchanger, and 53 is the fourth heat exchanger heater.

图3为本发明的低温甲醇洗工艺和CO₂压缩工艺的耦合方系统中，当CO₂收率为79%～91.2%时的系统示意图；其中：56、60、62、63、64、65、72为换热器，61为多级压缩机，68为泵，70循环水冷端，71、73为循环水热端，66压缩CO₂为产品气，67、69为液化CO₂产品；其余零件编号与图1中的相同零件编号表示相同的部件或物料；并且，在换热器中，60为第一换热器，27为第二换热器，56为第三换热器，53为第四换热器，72是第五换热器。Fig. 3 is the low-temperature methanol washing process of the present invention and_CO Compression process in the coupling system, when CO_The yield is 79% ~ 91.2% system schematic diagram; wherein: 56, 60, 62, 63, 64, 65 , 72 is a heat exchanger, 61 is a multi-stage compressor, 68 is a pump, 70 is a circulating water cooling end, 71, 73 is a circulating water heating end, 66 is compressed_CO2 as a product gas, 67, 69 is a liquefied_CO2 product; the rest The part number and the same part number in Fig. 1 represent the same parts or materials; and, in the heat exchanger, 60 is the first heat exchanger, 27 is the second heat exchanger, 56 is the third heat exchanger, 53 Is the fourth heat exchanger, 72 is the fifth heat exchanger.

具体实施方式Detailed ways

下面结合实施例和附图对本发明作进一步详细的描述，但本发明的实施方式不限于此。The present invention will be further described in detail below with reference to the examples and drawings, but the implementation of the present invention is not limited thereto.

参见图1～图3，低温甲醇洗工艺和CO₂压缩工艺的耦合方法和系统中，所述低温甲醇洗工艺中的低温甲醇洗装置的基本构成（参见图2和图3）与申请号为201310247525.0的发明专利申请中所公开的一种高CO₂收率的低温甲醇洗装置（参见图1）相同，具体由吸收塔4、CO₂解吸塔14、H₂S浓缩塔19、甲醇热再生塔28、甲醇精馏塔43、多个闪蒸塔、多个换热器、多个泵以及多个压缩机等组成，CO₂解吸塔14底与H₂S浓缩塔19之间设有CO₂闪蒸塔50，且图2、图3与图1中相同的零件标号表示相同的部件或物料，因此对于相同的部分，申请号为201310247525.0的发明专利申请中对图1的工艺流程及装置的描述适用于本实施例对图2、图3的描述，此处不再重复。Referring to Figures 1 to 3, in the coupling method and system of the low-temperature methanol washing process and the_CO2 compression process, the basic composition of the low-temperature methanol washing device in the low-temperature methanol washing process (see Figures 2 and 3) and the application number are A low-temperature methanol washing device with high CO₂ yield (see Figure 1) disclosed in the invention patent application of 201310247525.0 is the same, specifically consists of absorption tower 4, CO₂ desorption tower 14, H₂S concentration tower 19, methanol thermal regeneration tower 28,methanol rectification tower 43, multiple flash towers, multiple heat exchangers, multiple pumps, and multiple compressors,_etc. , and_a CO₂ flash tower 50, and the same part number in Fig. 2, Fig. 3 and Fig. 1 represents the same component or material, so for the same part, the process flow and device of Fig. 1 in the invention patent application with application number 201310247525.0 The description of is applicable to the description of FIG. 2 and FIG. 3 in this embodiment, and will not be repeated here.

本发明的低温甲醇洗装置与图1所示低温甲醇洗装置的不同之处在于，本发明中，所述CO₂解吸塔14塔底的甲醇富液16不是通过外部的热源进行加热，而是与CO₂压缩工艺中的热源进行耦合，从而获得热量。The difference between the low-temperature methanol washing device of the present invention and the low-temperature methanol washing device shown in Figure 1 is that in the present invention, the methanol-rich liquid 16 at the bottom of the_COdesorption tower 14 is not heated by an external heat source, but Coupling with a heat source in the CO₂ compression process to obtain heat.

本发明的CO₂压缩工艺具有CO₂多级压缩装置和泵提压装置，与现有技术的不同之处在于，CO₂多级压缩装置末端的压缩CO₂产品气不是通过外部的冷源进行降温液化，而是与低温甲醇洗工艺中的冷源进行耦合，从而获得本发明所述的低温甲醇洗工艺和CO₂压缩工艺的耦合方法和系统。The_CO2 compression process of the present invention has a_CO2 multi-stage compression device and a pump pressure-_lifting device, and the difference from the prior art is that the compressed_CO2 product gas at the end of the CO2 multi-stage compression device is not carried out by an external cold source Instead of cooling and liquefying, it is coupled with the cold source in the low-temperature methanol washing process, so as to obtain the coupling method and system of the low-temperature methanol washing process and_CO2 compression process described in the present invention.

具体地，本发明的低温甲醇洗工艺和CO₂压缩工艺的耦合方法包括以下步骤：将所述CO₂解吸塔14塔底的甲醇富液16和所述CO₂多级压缩装置末端的压缩CO₂产品气通过一个换热器进行耦合，耦合后的甲醇富液16送入所述CO₂闪蒸塔50，耦合后的压缩CO₂产品气降温液化成为液化CO₂产品再由泵提压装置提压至管道输送压力进行输送。Specifically, the coupling method of the low-temperature methanol washing process and the_CO2 compression process of the present invention includes the following steps: the methanol-rich liquid 16 at the bottom of the_CO2desorption tower 14 and the compressed CO at the end of the_CO2 multistage compression device_2. The product gas is coupled through a heat exchanger, and the coupled methanol-rich liquid 16 is sent to the CO₂ flash tower 50, and the coupled compressed CO₂ product gas is cooled and liquefied to become a liquefied CO₂ product, which is then pumped by a pump Raise the pressure to the pipeline delivery pressure for delivery.

本发明的低温甲醇洗工艺和CO₂压缩工艺的耦合系统为：CO₂解吸塔14塔底通过管道连接于第一换热器60后再与所述CO₂闪蒸塔50连接，所述CO₂多级压缩装置末端通过管道连接于所述第一换热器60后再与泵提压装置连接。The low-temperature methanol washing process of the present invention and the_coupling system of the CO compression process are: the bottom of the_COdesorption tower 14 is connected to thefirst heat exchanger 60 through a pipeline and then connected with the_COflash tower 50, and the CO_2. The end of the multi-stage compression device is connected to thefirst heat exchanger 60 through pipelines and then connected to the pump pressure raising device.

更进一步地，由于当低温甲醇洗工艺中CO₂的收率不同时，述CO₂解吸塔14塔底的甲醇富液16在进入CO₂闪蒸塔50之前的温度要求不同，CO₂的收率越高，需要的温度也越高。同时，基于低温冷量梯级利用的原则，将所述CO₂解吸塔底14的甲醇富液16冷量进行梯级换热，即依次与循环甲醇贫液37、CO₂闪蒸塔50塔顶的压缩富CO₂气51、多级压缩过程的CO₂产品气换热，从而获得图2的技术方案。但是随着CO₂收率的提高，CO₂闪蒸塔50的操作压力降低，压缩机52功耗增大，富CO₂气51压缩后温度明显提高，在CO₂收率为79-80%时，富CO₂气51压缩后温度在42-60℃之间，在CO₂收率高于80%范围时，压缩富CO₂气51需经过循环冷却水冷却降温，而不适合直接利用CO₂解吸塔底14的甲醇富液16冷量；并且，随着CO₂收率的提高，CO₂闪蒸塔50的操作温度也相应提高，进入CO₂闪蒸塔的甲醇富液温度升温明显，因此经过多级压缩后的CO₂产品气的热量不足以达到操作要求，而CO₂多级压缩装置中产生的循环水热端则可以补充更多的热量，结合该特点，形成图3所示的技术方案。Further, because when the yield of_CO in the low-temperature methanol washing process is different, the methanol rich liquid 16 at the bottom of the_COdesorption tower 14 has different temperature requirements before entering the_COflash tower 50, and the yield of_{CO is} different. The higher the rate, the higher the temperature required. Simultaneously, based on the principle of cascade utilization of low-temperature cooling capacity, the cooling capacity of the methanol_- rich liquid 16 at the bottom 14 of the CO desorption tower is subjected to cascaded heat exchange, that is, with the circulating methanollean liquid 37 and_the CO at the top of theflash tower 50 successively. Compress CO₂ -enrichedgas 51 and exchange heat with the CO₂ product gas in the multi-stage compression process, so as to obtain the technical solution in Fig. 2 . However, as the_CO2 yield increases, the operating pressure of the_CO2flash tower 50 decreases, the power consumption of thecompressor 52 increases, and the temperature of the_CO2-rich gas 51 after compression increases significantly, and the_CO2 yield is 79-80%. When the compressed CO₂rich gas 51 is compressed, the temperature is between 42-60°C. When the CO₂ yield is higher than 80%, the compressed CO₂rich gas 51 needs to be cooled by circulating cooling water, and it is not suitable for direct utilization of CO_2. The cooling capacity of methanol-rich liquid 14 at the bottom of thedesorption tower 14; and, along with the increase of_CO2 yield, the operating temperature of_CO2flash tower 50 also increases accordingly, and the temperature of methanol_- rich liquid entering the CO2 flash tower heats up significantly , so the heat of the CO₂ product gas after multi-stage compression is not enough to meet the operating requirements, while the hot end of the circulating water generated in the CO₂ multi-stage compression device can supplement more heat. Combining this feature, the formation of Figure 3 The technical solution shown.

下面实施例1和实施例2为收率为60.4%～79%时的具体实施方式，实施例3和实施例4为收率为80%～91.2%时的具体实施方式。Thefollowing embodiment 1 andembodiment 2 are specific implementations when the yield is 60.4% to 79%, andembodiment 3 and embodiment 4 are specific implementations when the yield is 80% to 91.2%.

实施例1Example 1

参见图2，本实施例的低温甲醇洗工艺和CO₂压缩工艺的耦合方法包括以下步骤:Referring to Fig. 2, the low-temperature methanol washing process of the present embodiment and_CO The coupling method of compression process comprises the following steps:

（1）低温甲醇洗工艺中再生产生的甲醇贫液37与H₂S浓缩塔19塔底的甲醇富液22以及CO₂解吸塔14塔底的甲醇富液16分别进行热交换降温后输送至酸性气体吸收塔4塔顶；(1) Thelean methanol solution 37 generated in the low-temperature methanol washing process is heat-exchanged with the methanol-rich solution 22 at the bottom of the H₂S concentration tower 19 and the methanol-rich solution 16 at the bottom of the CO₂ desorption tower 14, and then transported to Acid gas absorption tower 4 tower top;

（2）CO₂解吸塔14塔底的甲醇富液16与甲醇贫液37热交换升温后，再与CO₂闪蒸塔50塔顶的富CO₂气51进行热交换升温，然后与CO₂多级压缩装置末端的压缩CO₂产品气66通过一个换热器进行耦合升温，最后送入所述CO₂闪蒸塔50。(2) After the methanol-rich liquid 16 at the bottom of the CO₂ desorption tower 14 heats up with the methanol-poor liquid 37, it heats up with the CO_2-rich gas 51 at the top of the CO₂ flash tower 50, and then heats up with the CO₂ The compressed CO₂ product gas 66 at the end of the multi-stage compression device is coupled and heated through a heat exchanger, and finally sent to the CO₂ flash tower 50 .

本实施例的低温甲醇洗工艺和CO₂压缩工艺的耦合系统为：所述低温甲醇洗工艺中再生产生的甲醇贫液37的输送管分别与H2S浓缩塔19塔底连接在第二换热器27上、与CO₂解吸塔14塔底连接在第三换热器56上；所述CO₂解吸塔14通过管道连接于所述第三换热器56上后，再与CO₂闪蒸塔50塔顶连接于第四换热器53上，然后与所述第一换热器60连接，最后与所述CO₂闪蒸塔50连接。The coupling system of the low-temperature methanol washing process and the_CO2 compression process of this embodiment is: the delivery pipes of the methanol lean liquid 37 regenerated in the low-temperature methanol washing process are respectively connected to the bottom of theH2S concentration tower 19 in thesecond heat exchanger 27, with the_CO2desorption tower 14 tower bottoms are connected on thethird heat exchanger 56; after the_CO2desorption tower 14 is connected to thethird heat exchanger 56 through pipelines, it is connected with the_CO2 flash tower The top of the 50 tower is connected to thefourth heat exchanger 53, then connected to thefirst heat exchanger 60, and finally connected to the CO₂ flash tower 50.

所述CO₂多级压缩装置包括具有四个压缩汽缸的压缩机61和多个换热器62、63、64、65，所述每个压缩汽缸上设置有一个换热器，每个换热器分别与进水管和出水管连接，所述进水管构成循环冷水冷端70，出水管构成循环水热端71。所述泵提压装置包括泵67以及输送管道。The_CO2 multistage compression device includes acompressor 61 with four compression cylinders and a plurality ofheat exchangers 62, 63, 64, 65, each compression cylinder is provided with a heat exchanger, and each heat exchanger The device is respectively connected with the water inlet pipe and the water outlet pipe, the water inlet pipe constitutes the circulating cold watercold end 70, and the water outlet pipe constitutes the circulating waterhot end 71. The pump pressure raising device includes apump 67 and a delivery pipeline.

下面结合具体的例子对本实施例的耦合方法和耦合系统的工作过程作进一步详细的描述：The working process of the coupling method and the coupling system of this embodiment will be further described in detail in combination with specific examples:

参见图2，进入本发明工艺的粗合成气1来自以煤为原料，德士古气化得到的耐硫变换合成气，从变换工段来的气体流量为95760Nm³/hr，组成如下表。Referring to Fig. 2, thecrude synthesis gas 1 entering the process of the present invention comes from the sulfur-resistant shifted synthesis gas obtained from Texaco gasification with coal as raw material. The gas flow rate from the shifting section is 95760Nm³ /hr, and its composition is shown in the following table.

表2粗气化煤气的成分Table 2 Composition of crude gasification gas

气体gasH₂H₂N₂N₂COCOARARCH₄CH₄CO₂CO₂H₂SH₂ SH₂OH₂ O摩尔分数%Mole fraction %45.645.60.30.319.219.20.10.10.10.134.334.30.20.20.20.2

进入流程的原料气1在经换热器2冷却后进入闪蒸塔3，从塔底分离出水甲醇溶液48。从闪蒸塔3塔顶出的脱水合成气进入吸收塔4底部，吸收塔4顶部注入低温甲醇液47，流量168.2t/hr，操作温度-50℃，操作压力35bar。在吸收塔4塔顶得到净化合成气5。不含H₂S的甲醇富液7和富H₂S甲醇富液6分别经过降温减压后，进入闪蒸塔11和闪蒸塔13，进行闪蒸分离。Theraw material gas 1 entering the process enters theflash tower 3 after being cooled by theheat exchanger 2, and the water-methanol solution 48 is separated from the bottom of the tower. The dehydrated synthesis gas from the top of theflash tower 3 enters the bottom of the absorption tower 4, and the top of the absorption tower 4 is injected with a low-temperature methanol liquid 47, with a flow rate of 168.2t/hr, an operating temperature of -50°C, and an operating pressure of 35bar.Purified synthesis gas 5 is obtained at the top of the absorption tower 4 . The H₂ S-free methanol-rich solution 7 and the H₂ S-rich methanol-rich solution 6 respectively enter the flash tower 11 and the flash tower 13 after being cooled and decompressed for flash separation.

闪蒸塔11、13塔底的甲醇富液进入CO₂解吸过程。CO₂解吸塔14塔底甲醇富液16进入CO₂闪蒸塔50之前，先后经过换热器56、53、60，以充分回收利用解吸过程产生的低温冷量，其中，经过换热器56后，操作温度为-34℃，经过换热器53后，操作温度为-31℃，经过换热器60后，操作温度为-26℃；CO₂闪蒸塔50的操作压力为2.5bar。CO₂闪蒸塔50顶出的富CO₂气51经过加压降温后输送至CO₂解吸塔14塔底，经换热器53后温度降温-31℃，压缩机52操作压力为4bar。闪蒸塔13塔顶得到体积浓度为99.1%的CO₂产品气15，产品气流量为20068Nm³/hr，CO₂产品气15的收率为60.4%。The methanol-rich liquid at the bottom of flash towers 11 and 13 enters the_CO2 desorption process. Before the methanol-rich liquid 16 at the bottom of the_CO2desorption tower 14 enters the_CO2flash tower 50, it passes through theheat exchangers 56, 53, and 60 successively to fully recycle the low-temperature cooling capacity generated during the desorption process, wherein, through theheat exchanger 56 Finally, the operating temperature is -34°C. After passing through theheat exchanger 53, the operating temperature is -31°C. After passing through theheat exchanger 60, the operating temperature is -26°C; the operating pressure of the CO₂ flash tower 50 is 2.5bar. The CO₂ -enrichedgas 51 ejected from the CO₂ flash tower 50 is pressurized and lowered in temperature and then sent to the bottom of the CO₂ desorption tower 14 , the temperature drops to -31°C after passing through theheat exchanger 53 , and the operating pressure of thecompressor 52 is 4 bar. The CO₂ product gas 15 with a volume concentration of 99.1% is obtained from the top of the flash tower 13, the flow rate of the product gas is 20068 Nm³ /hr, and the yield of the CO₂ product gas 15 is 60.4%.

CO₂产品气15经换热器2后进入多级间接冷却压缩过程，CO₂产品气15经过多级压缩装置间接冷却至操作温度40℃，压力为70bar。压缩CO₂产品气66经换热器60得到液化CO₂产品，操作温度为21℃，通过泵68进行提压至管道输送压力150bar。The CO₂ product gas 15 enters the multi-stage indirect cooling compression process after passing through theheat exchanger 2, and the CO₂ product gas 15 is indirectly cooled to an operating temperature of 40°C and a pressure of 70 bar through the multi-stage compression device. The compressed CO₂ product gas 66 passes through theheat exchanger 60 to obtain the liquefied CO₂ product, the operating temperature is 21°C, and the pressure is raised by thepump 68 to the pipeline delivery pressure of 150 bar.

实施例2Example 2

本实施例的低温甲醇洗工艺和CO₂压缩工艺的耦合方法和系统与实施例1相同，不同之处在于：CO₂收率不同，因此相应的操作温度也不同。具体如下：The coupling method and system of the low-temperature methanol washing process and the_CO2 compression process in this embodiment are the same as in Example 1, except that the_CO2 yield is different, so the corresponding operating temperature is also different. details as follows:

参见图2，CO₂解吸塔14塔底甲醇富液16进入CO₂闪蒸塔50之前，先后经过换热器56、53、60，以充分回收利用解吸过程产生的低温冷量，其中，经过换热器56后，操作温度为-33℃，经过换热器53后，操作温度为-26℃，经过换热器60后，操作温度为-5℃，CO₂闪蒸塔50的操作压力为1.7bar。CO₂闪蒸塔50顶出的富CO₂气51经过加压降温后输送至CO₂解吸塔14塔底，经换热器53后温度降温-30.5℃，压缩机52操作压力为4bar。闪蒸塔13塔顶得到体积浓度为99.0%的CO₂产品气15，产品气流量为25357Nm³/hr，CO₂产品气15的收率为78.3%。Referring to Fig. 2, the methanol-rich liquid 16 at the bottom of the_CO2desorption tower 14 enters the_CO2flash tower 50, and passes throughheat exchangers 56, 53, and 60 successively to fully recycle the low-temperature cooling capacity generated during the desorption process. Afterheat exchanger 56, the operating temperature is -33°C, after passing throughheat exchanger 53, the operating temperature is -26°C, after passing throughheat exchanger 60, the operating temperature is -5°C, the operating pressure of_CO2flash tower 50 It is 1.7bar. The CO₂ -rich gas 51 ejected from the CO₂ flash tower 50 is pressurized and cooled and then sent to the bottom of the CO₂ desorption tower 14 , the temperature drops to -30.5°C after passing through theheat exchanger 53 , and the operating pressure of thecompressor 52 is 4 bar. The CO₂ product gas 15 with a volume concentration of 99.0% is obtained from the top of the flash tower 13, the flow rate of the product gas is 25357 Nm³ /hr, and the yield of the CO₂ product gas 15 is 78.3%.

CO₂产品气15经换热器2后进入多级间接冷却压缩过程，CO₂产品气15经过多级压缩装置间接冷却至操作温度40℃，压力为65bar。压缩CO₂产品气66经换热器60得到液化CO₂产品，操作温度为15℃，通过泵68进行提压至管道输送压力150bar。The CO₂ product gas 15 enters the multi-stage indirect cooling and compression process after passing through theheat exchanger 2, and the CO₂ product gas 15 is indirectly cooled to an operating temperature of 40°C and a pressure of 65 bar through the multi-stage compression device. The compressed CO₂ product gas 66 passes through theheat exchanger 60 to obtain the liquefied CO₂ product, the operating temperature is 15°C, and the pressure is raised by thepump 68 to the pipeline delivery pressure of 150 bar.

本实施例上述以外的其他实施方式与实施例1相同Other implementations other than the above in this embodiment are the same as inEmbodiment 1

实施例3Example 3

参见图3，本实施例的低温甲醇洗工艺和CO₂压缩工艺的耦合方法包括以下步骤:Referring to Fig. 3, the low-temperature methanol washing process of the present embodiment and the CO_The coupling method of the compression process comprises the following steps:

（1）低温甲醇洗工艺中再生产生的甲醇贫液37与H₂S浓缩塔19塔底的甲醇富液22以及CO₂解吸塔14塔底的甲醇富液16分别进行热交换降温后输送至酸性气体吸收塔4塔顶；(1) Thelean methanol solution 37 generated in the low-temperature methanol washing process is heat-exchanged with the methanol-rich solution 22 at the bottom of the H₂S concentration tower 19 and the methanol-rich solution 16 at the bottom of the CO₂ desorption tower 14, and then transported to Acid gas absorption tower 4 tower top;

（2）CO₂解吸塔14塔底的甲醇富液16与甲醇贫液37热交换升温后，再与CO₂多级压缩装置末端的压缩CO₂产品气66通过一个换热器进行耦合升温，然后与CO₂多级压缩装置中的循环水热端71进行热交换升温，最后送入所述CO₂闪蒸塔50。(2) After the methanol_- rich liquid 16 at the bottom of theCO2 desorption tower 14 is heat-exchanged with the methanol-poor liquid 37 to raise the temperature, it is coupled with the compressed_CO2 product gas 66 at the end of the_CO2 multi-stage compression device through a heat exchanger to raise the temperature. Then it exchanges heat with the circulating waterhot end 71 in the_CO2 multistage compression device to raise the temperature, and finally sends it to the_CO2flash tower 50.

本实施例的低温甲醇洗工艺和CO₂压缩工艺的耦合系统为：所述低温甲醇洗工艺中再生产生的甲醇贫液37的输送管分别与H₂S浓缩塔19塔底连接在第二换热器27上、与CO₂解吸塔14塔底连接在第三换热器56上；所述CO₂解吸塔14塔底通过管道连接于所述第三换热器56上后，再与所述第一换热器60连接，然后与所述出水管连接在第五换热器72上，最后与所述CO₂闪蒸塔50连接。The coupling system of the low-temperature methanol washing process and the_CO2 compression process in this embodiment is: the delivery pipes of the methanol lean liquid 37 regenerated in the low-temperature methanol washing process are respectively connected to the bottom of the_H2Sconcentration tower 19 at the second exchange On theheat exchanger 27, it is connected with thethird heat exchanger 56 at the_bottom of the_COdesorption tower 14; Thefirst heat exchanger 60 is connected, then the outlet pipe is connected to thefifth heat exchanger 72, and finally the CO₂ flash tower 50 is connected.

下面结合具体的例子对本实施例的耦合方法和耦合系统的工作过程作进一步详细的描述：The working process of the coupling method and the coupling system of this embodiment will be further described in detail in combination with specific examples:

进入本发明工艺的原料气来自以煤为原料，德士古气化得到的耐硫变换合成气，从变换工段来的气体流量为104292Nm^3/hr，组成如下表，工艺流程见图3。The raw material gas entering the process of the present invention comes from the sulfur-resistant shift synthesis gas obtained by Texaco gasification with coal as raw material. The gas flow rate from the shift section is 104292Nm^{3 /} hr. The composition is as follows. The process flow is shown in Figure 3.

表3粗气化煤气的成分Table 3 Composition of crude gasification gas

气体gasH₂H₂N₂N₂COCOARARCH₄CH₄CO₂CO₂H₂SH₂ SH₂OH₂ O摩尔分数%Mole fraction%45.945.90.20.218.918.90.10.10.10.134.234.20.130.130.30.3

进入流程的原料气1在经换热器2冷却后进入闪蒸塔3，从塔底分离出水甲醇溶液48。从闪蒸塔3塔顶出的脱水合成气进入吸收塔4底部，吸收塔4顶部注入低温甲醇液47，流量186.8t/hr，操作温度-50℃，操作压力35bar。在吸收塔4塔顶得到净化合成气5。不含H₂S的甲醇富液7和富H₂S甲醇富液6分别经过降温减压后，进入闪蒸塔11和闪蒸塔13，进行闪蒸分离。Theraw material gas 1 entering the process enters theflash tower 3 after being cooled by theheat exchanger 2, and the water-methanol solution 48 is separated from the bottom of the tower. The dehydrated synthesis gas from the top of theflash tower 3 enters the bottom of the absorption tower 4, and the top of the absorption tower 4 is injected with a low-temperature methanol liquid 47, with a flow rate of 186.8t/hr, an operating temperature of -50°C, and an operating pressure of 35bar.Purified synthesis gas 5 is obtained at the top of the absorption tower 4 . The H₂ S-free methanol-rich solution 7 and the H₂ S-rich methanol-rich solution 6 respectively enter the flash tower 11 and the flash tower 13 after being cooled and decompressed for flash separation.

闪蒸塔11、13塔底的甲醇富液进入CO₂解吸过程。CO₂解吸塔14塔底甲醇富液16进入CO₂闪蒸塔50之前，先后经过换热器56、60、72，以充分回收利用解吸过程产生的低温冷量，其中，经过换热器56后，操作温度为-25℃，经过换热器60后，操作温度为6℃，经过换热器72后，操作温度为-2℃，CO₂闪蒸塔50的操作压力为1.5bar。CO₂闪蒸塔50顶出的富CO₂气51经过加压降温后输送至CO₂解吸塔14塔底，经换热器53后温度降温-31℃，压缩机52操作压力为4bar。闪蒸塔13塔顶得到体积浓度为99.1%的CO₂产品气15，产品气流量为28883.5Nm³/hr，CO₂产品气15的收率为80.9%。The methanol-rich liquid at the bottom of flash towers 11 and 13 enters the_CO2 desorption process. Before the methanol-rich liquid 16 at the bottom of the_CO2desorption tower 14 enters the_CO2flash tower 50, it passes throughheat exchangers 56, 60, and 72 to fully recover and utilize the low-temperature cooling capacity produced during the desorption process. Finally, the operating temperature is -25°C. After passing through theheat exchanger 60, the operating temperature is 6°C. After passing through theheat exchanger 72, the operating temperature is -2°C. The operating pressure of the CO₂ flash tower 50 is 1.5 bar. The CO₂ -enrichedgas 51 ejected from the CO₂ flash tower 50 is pressurized and lowered in temperature and then sent to the bottom of the CO₂ desorption tower 14 , the temperature drops to -31°C after passing through theheat exchanger 53 , and the operating pressure of thecompressor 52 is 4 bar. The CO₂ product gas 15 with a volume concentration of 99.1% is obtained from the top of the flash tower 13, the flow rate of the product gas is 28883.5 Nm³ /hr, and the yield of the CO₂ product gas 15 is 80.9%.

CO₂产品气15经换热器2后进入多级间接冷却压缩过程，CO₂产品气15经过多级压缩装置间接冷却至操作温度40℃，压力为65bar。压缩CO₂产品气66经换热器60得到液化CO₂产品，操作温度为17℃，通过泵68进行提压至管道输送压力150bar。The CO₂ product gas 15 enters the multi-stage indirect cooling and compression process after passing through theheat exchanger 2, and the CO₂ product gas 15 is indirectly cooled to an operating temperature of 40°C and a pressure of 65 bar through the multi-stage compression device. The compressed CO₂ product gas 66 passes through theheat exchanger 60 to obtain the liquefied CO₂ product, the operating temperature is 17°C, and the pressure is raised by thepump 68 to the pipeline delivery pressure of 150 bar.

实施例4Example 4

具体实施如下：The specific implementation is as follows:

参见图3，本实施例的低温甲醇洗工艺和CO₂压缩工艺的耦合方法和系统与实施例3相同，不同之处在于：CO₂收率不同，因此相应的操作温度也不同。具体如下：Referring to Fig. 3, the coupling method and system of the low-temperature methanol washing process and the CO₂ compression process in this embodiment are the same as inEmbodiment 3, except that the CO₂ yield is different, so the corresponding operating temperature is also different. details as follows:

CO₂解吸塔14塔底甲醇富液16进入CO₂闪蒸塔50之前，先后经过换热器56、60、72，以充分回收利用解吸过程产生的低温冷量，其中，经过换热器56后，操作温度为-2℃，经过换热器60后，操作温度为17℃，经过换热器72后，操作温度为35℃，CO₂闪蒸塔50的操作压力为1bar。CO₂闪蒸塔50顶出的富CO₂气51经过加压降温后输送至CO₂解吸塔14塔底，经换热器53后温度降温-32℃，压缩机52操作压力为4bar。闪蒸塔13塔顶得到体积浓度为99.3%的CO₂产品气15，产品气流量为32431Nm³/hr，CO₂产品气15的收率为91.2%。Before the methanol-rich liquid 16 at the bottom of the_CO2desorption tower 14 enters the_CO2flash tower 50, it passes throughheat exchangers 56, 60, and 72 to fully recover and utilize the low-temperature cooling capacity produced during the desorption process. Finally, the operating temperature is -2°C. After passing through theheat exchanger 60, the operating temperature is 17°C. After passing through theheat exchanger 72, the operating temperature is 35°C. The operating pressure of the CO₂ flash tower 50 is 1 bar. The CO₂ -rich gas 51 ejected from the CO₂ flash tower 50 is pressurized and cooled and then transported to the bottom of the CO₂ desorption tower 14 , the temperature drops to -32°C after passing through theheat exchanger 53 , and the operating pressure of thecompressor 52 is 4 bar. The CO₂ product gas 15 with a volume concentration of 99.3% is obtained from the top of the flash tower 13, the flow rate of the product gas is 32431 Nm³ /hr, and the yield of the CO₂ product gas 15 is 91.2%.

CO₂产品气15经换热器2后进入多级间接冷却压缩过程，CO₂产品气15经过多级压缩装置间接冷却至操作温度40℃，压力为65bar。压缩CO₂产品气66经换热器60得到液化CO₂产品，操作温度为20℃，通过泵68进行提压至管道输送压力150bar。The CO₂ product gas 15 enters the multi-stage indirect cooling and compression process after passing through theheat exchanger 2, and the CO₂ product gas 15 is indirectly cooled to an operating temperature of 40°C and a pressure of 65 bar through the multi-stage compression device. The compressed CO₂ product gas 66 passes through theheat exchanger 60 to obtain the liquefied CO₂ product, the operating temperature is 20°C, and the pressure is raised by thepump 68 to the pipeline delivery pressure of 150 bar.

本实施例上述以外的其他实施方式与实施例3相同。Embodiments other than the above in this embodiment are the same as those inEmbodiment 3.

上述实施例为本发明较佳的实施方式，但本发明的实施方式并不受上述实施例的限制，其他的任何未背离本发明的精神实质与原理下所作的改变、修饰、替代、组合、简化，均应为等效的置换方式，都包含在本发明的保护范围之内。The above-mentioned embodiment is a preferred embodiment of the present invention, but the embodiment of the present invention is not limited by the above-mentioned embodiment, and any other changes, modifications, substitutions, combinations, Simplifications should be equivalent replacement methods, and all are included in the protection scope of the present invention.

Claims (9)

Translated fromChinese

1.一种低温甲醇洗工艺和CO₂压缩工艺的耦合方法，其中，低温甲醇洗工艺中的CO₂解吸塔底与H₂S浓缩塔之间设有CO₂闪蒸塔，CO₂压缩工艺具有CO₂多级压缩装置和泵提压装置，其特征在于，该耦合方法包括以下步骤：1. A low-temperature methanol wash process and_CO2Coupling method_of compression process, wherein, CO in the low-temperature methanol wash processThe bottom of the desorption tower and the_H2S concentration tower are provided with a_CO2Flash tower,_{CO2Compression} process Have CO_Multi -stage compression device and pump boosting device, it is characterized in that, this coupling method comprises the following steps:将所述CO₂解吸塔塔底的甲醇富液和所述CO₂多级压缩装置末端的压缩CO₂产品气通过一个换热器进行耦合，耦合后的甲醇富液送入所述CO₂闪蒸塔，耦合后的压缩CO₂产品气降温液化成为液化CO₂产品由泵提压装置提压至管道输送压力进行输送。Coupling the methanol-rich liquid at the bottom of the_CO2 desorption tower and the compressed_CO2 product gas at the end of the_CO2 multi-stage compression device through a heat exchanger, the coupled methanol-rich liquid is sent to the_CO2 flash In the distillation tower, the coupled compressed CO₂ product gas is cooled and liquefied into a liquefied CO₂ product, which is boosted by the pump pressure device to the pipeline delivery pressure for delivery.2.根据权利要求1所述的低温甲醇洗工艺和CO₂压缩工艺的耦合方法，其特征在于，当所述低温甲醇洗工艺中CO₂收率为60.4%～79%时，该耦合方法包括以下步骤:2. The low-temperature methanol washing process according to claim 1 and the coupling method of the_CO2 compression process, characterized in that, when the_CO2 yield is 60.4% to 79% in the low-temperature methanol washing process, the coupling method includes The following steps:（1）低温甲醇洗工艺中再生产生的甲醇贫液与H₂S浓缩塔塔底的甲醇富液以及CO₂解吸塔塔底的甲醇富液分别进行热交换降温后输送至酸性气体吸收塔塔顶；(1) The lean methanol solution generated in the low-temperature methanol washing process is exchanged with the methanol-rich solution at the bottom of the H₂ S concentration tower and the methanol-rich solution at the bottom of the CO₂ desorption tower, respectively, and then transported to the acid gas absorption tower top;（2）CO₂解吸塔塔底的甲醇富液与甲醇贫液热交换升温后，再与CO₂闪蒸塔塔顶的富CO₂气进行热交换升温，然后与CO₂多级压缩装置末端的压缩CO₂产品气通过一个换热器进行耦合升温，最后送入所述CO₂闪蒸塔。(2) After the methanol-rich liquid at the bottom of the CO₂ desorption tower is heated up by heat exchange with the methanol-poor liquid, it is then heated up by heat exchange with the CO_2- rich gas at the top of the CO 2 flash tower, and then heated up with the end of the CO₂ multi-stage compression device The compressed_CO2 product gas is coupled and heated through a heat exchanger, and finally sent to the_CO2 flash tower.3.根据权利要求1所述的低温甲醇洗工艺和CO₂压缩工艺的耦合方法，其特征在于，当所述低温甲醇洗工艺中CO₂收率为80%～91.2%时，该耦合方法包括以下步骤:3. The low-temperature methanol washing process according to claim 1 and the coupling method of the_CO2 compression process, characterized in that, when the_CO2 yield is 80% to 91.2% in the low-temperature methanol washing process, the coupling method includes The following steps:（1）低温甲醇洗工艺中再生产生的甲醇贫液与H₂S浓缩塔塔底的甲醇富液以及CO₂解吸塔塔底的甲醇富液分别进行热交换降温后输送至酸性气体吸收塔塔顶；(1) The lean methanol solution generated in the low-temperature methanol washing process is exchanged with the methanol-rich solution at the bottom of the H₂ S concentration tower and the methanol-rich solution at the bottom of the CO₂ desorption tower, respectively, and then transported to the acid gas absorption tower top;（2）CO₂解吸塔塔底的甲醇富液与甲醇贫液热交换升温后，再与CO₂多级压缩装置末端的压缩CO₂产品气通过一个换热器进行耦合升温，然后与CO₂多级压缩装置中的循环水热端进行热交换升温，最后送入所述CO₂闪蒸塔。(2) After the methanol-rich liquid at the bottom of the CO₂ desorption tower is heat-exchanged with the methanol-lean liquid to raise the temperature, it is coupled with the compressed CO₂ product gas at the end of the CO₂ multi-stage compression device through a heat exchanger to raise the temperature, and then with CO₂ The hot end of the circulating water in the multi-stage compression device is subjected to heat exchange to raise the temperature, and finally sent to the CO₂ flash tower.4.根据权利要求2所述的低温甲醇洗工艺和CO₂压缩工艺的耦合方法，其特征在于，CO₂解吸塔塔底的甲醇富液与甲醇贫液热交换升温后，操作温度为-33～-31℃；再与CO₂闪蒸塔塔顶的富CO₂气进行热交换升温后，操作温度为-31～-28℃；再与CO₂多级压缩装置末端的压缩CO₂产品气通过一个换热器进行耦合升温后，操作温度为-26～-6℃。_4. The low-temperature methanol washing process and the_CO2 compression process coupling method according to claim 2, characterized in that, after the methanol-rich liquid at the bottom of the CO2 stripping tower and the methanol-poor liquid are heat-exchanged and heated, the operating temperature is -33 ~-31°C; then heat exchange with the_CO2- rich gas at the top of the CO2 flash tower to raise the temperature, the operating temperature is -31~-28°C; then with the compressed_CO2 product gas at the end of the_CO2 multi-stage compression device After coupled temperature rise through a heat exchanger, the operating temperature is -26~-6°C.5.根据权利要求3所述的低温甲醇洗工艺和CO₂压缩工艺的耦合方法，其特征在于，CO₂解吸塔塔底的甲醇富液与甲醇贫液热交换升温后，操作温度为-24～0℃；再与CO₂多级压缩装置末端的压缩CO₂产品气通过一个换热器进行耦合升温后，操作温度为-6～18℃；再与CO₂多级压缩装置中的循环水热端进行热交换升温后，操作温度为-6～35℃。5. The low-temperature methanol washing process according to claim 3 and the coupling method of the_CO2 compression process, characterized in that, after the methanol-rich liquid at the bottom of the_CO2 desorption tower and the methanol-poor liquid are heat-exchanged and heated, the operating temperature is -24 ~0°C; then coupled with the compressed CO₂ product gas at the end of the CO₂ multistage compression device through a heat exchanger, the operating temperature is -6~18°C; then combined with the circulating water in the CO₂ multistage compression device After heat exchange at the hot end, the operating temperature ranges from -6 to 35°C.6.一种低温甲醇洗工艺和CO₂压缩工艺的耦合系统，其中，低温甲醇洗工艺中的CO₂解吸塔底与H₂S浓缩塔之间设有CO₂闪蒸塔，CO₂压缩工艺具有CO₂多级压缩装置和泵提压装置，其特征在于，所述CO₂解吸塔塔底通过管道连接于第一换热器后再与所述CO₂闪蒸塔连接，所述CO₂多级压缩装置末端通过管道连接于所述第一换热器后再与泵提压装置连接。6. A coupling system of a low-temperature methanol washing process and a_CO2 compression process, wherein a_CO2 flash tower is arranged between the bottom of the_CO2 desorption tower in the low-temperature methanol washing process and the_H2S concentration tower, and the_CO2 compression process It has a_CO2 multi-stage compression device and a pump pressure-lifting device, and it is characterized in that the bottom of the_CO2 desorption tower is connected to the first heat exchanger through a pipeline and then connected to the_CO2 flash tower, and the_CO2 The end of the multistage compression device is connected to the first heat exchanger through pipelines and then connected to the pump pressure raising device.7.根据权利要求6所述的低温甲醇洗工艺和CO₂压缩工艺的耦合系统，其特征在于，所述CO₂多级压缩装置包括具有多级压缩汽缸的压缩机和多个换热器，所述每级压缩汽缸外设置有换热器，每个换热器分别与进水管和出水管连接。7. low-temperature methanol washing process and CO according to claim 6 The coupled system of compression process_is characterized in that, said CO_multistage compression device comprises a compressor with a multistage compression cylinder and a plurality of heat exchangers, A heat exchanger is arranged outside each compression cylinder, and each heat exchanger is connected with a water inlet pipe and a water outlet pipe respectively.8.根据权利要求7所述的低温甲醇洗工艺和CO₂压缩工艺的耦合系统，其特征在于，所述低温甲醇洗工艺中再生产生的甲醇贫液的输送管分别与H₂S浓缩塔塔底连接在第二换热器上、与CO₂解吸塔塔底连接在第三换热器上；8. The low temperature methanol washing process according to claim 7 and the coupling system of the_CO2 compression process, characterized in that, the delivery pipes of the lean methanol solution regenerated in the low temperature methanol washing process are respectively connected to the_H2S concentration tower The bottom is connected to the second heat exchanger, and the bottom of the_CO desorption tower is connected to the third heat exchanger;所述CO₂解吸塔塔底通过管道连接于所述第三换热器上后，再与CO₂闪蒸塔塔顶连接于第四换热器上，然后与所述第一换热器连接，最后与所述CO₂闪蒸塔连接。After the bottom of the_CO desorption tower is connected to the third heat exchanger through a pipeline, it is connected with the top of the_CO flash tower to the fourth heat exchanger, and then connected to the first heat exchanger , and finally connected with the CO₂ flash tower.9.根据权利要求7所述的低温甲醇洗工艺和CO₂压缩工艺的耦合系统，其特征在于，所述低温甲醇洗工艺中再生产生的甲醇贫液的输送管分别与H₂S浓缩塔塔底连接在第二换热器上、与CO₂解吸塔塔底连接在第三换热器上；9. The low-temperature methanol washing process according to claim 7 and the coupling system of the_CO2 compression process, characterized in that, the delivery pipes of the lean methanol solution regenerated in the low-temperature methanol washing process are respectively connected to the_H2S concentration tower The bottom is connected to the second heat exchanger, and the bottom of the_CO desorption tower is connected to the third heat exchanger;所述CO₂解吸塔塔底通过管道连接于所述第三换热器上后，再与所述第一换热器连接，然后与所述出水管连接在第五换热器上，最后与所述CO₂闪蒸塔连接。The_CO desorption tower bottom is connected to the third heat exchanger through a pipeline, then connected to the first heat exchanger, then connected to the fifth heat exchanger with the water outlet pipe, and finally connected to the fifth heat exchanger. The_CO2 flash column is connected.

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