SU1155613A1 - Method of catalytic reforming - Google Patents

Abstract

A CATALYTIC REFORMING METHOD of a gasoline fraction in the presence of a hydrogen-containing gas in an adiabatic reactor, the subsequent cooling of the gas-product mixture in the raw heat exchanger and the refrigerator and stabilization with entrainment of the target product, characterized in that, in order to reduce energy costs and improve the efficiency of the product, the gas product will be used to increase the efficiency of the process, gas-product, and the product will be used to increase the efficiency of the process, gas-product, and the product will be used to increase the efficiency of the product, gas-product, and the product will be reduced. cooled in a heat exchanger with a circulating coolant and cooled down to 5-35 ° C circus after the cooler liruyupschm refrigerant and heat the circulating heating medium after the heat exchanger disposed in a refrigerating machine for cooling refrigerant circulating § audio to 5-35 °. C (/) ate O1 O) with

Description

11 The invention relates to catalytic reforming methods and may be used in the refining and petrochemical industry. A known method of carrying out a catalytic reforming process is that the feedstock, together with the circulating gas containing gas, is heated and passes through a cascade of reactors operating in an adiabatic regimen provided by intermediate heating in furnaces, followed by separation and stabilization of the gas raw material mixture. The disadvantage of this method is the direct dependence of the stable operation of the installation on the ambient temperature. As a result of the unstable operation of the separation unit, the hydrogen concentration in the circulating gas can be drastically reduced and, thus, the stability of the catalyst deteriorates. Closest to the invention is a method of catalytic reforming by converting the gasoline fraction under a pressure of 0.9-1 MPa in the presence of hydrogen-containing first gas (400-500 m / m of raw material) in an adiabatic reactor, subsequent cooling of the gas product mixture in the raw heat exchanger and refrigerator and stabilization with the release of the target product 2. The disadvantage of this method is the inefficient use of the secondary heat of the gas product mixture and the additional energy costs for its cooling, as well as the dependence tabilnosti separation operation the low pressure of the ambient temperature environment block, which leads to loss of yield of the desired products. The purpose of the invention is to increase the efficiency of the process through the efficient use of secondary energy resources, as well as increasing the stability of the catalyst and the yield of reformed gasoline. The goal is achieved by the method of catalytic reforming of a gasoline fraction in the presence of a hydrogen-containing gas in an adiabatic reactor, subsequent cooling of the gas product mixture in the raw material heat exchanger, then in 3 heat exchanger, circulating coolant, then in the refrigerator and further cooling with the circulating refrigerant. circulating coolant in the chiller to cool the circulating refrigerant to 5-35 ° C. The proposed technical solution makes it possible, regardless of the season, to maintain the separation temperature in the range of 35–5 ° C, to improve the quality of hydrogen-containing gas, to reduce the specific energy consumption at the facility, to increase the stability of the catalyst, the duration of regeneration cycles, and the yield of reforming benzine. To implement the catalytic reforming method, it is proposed to use process water with a content of particles of not more than 75 mg / l as a refrigerant; hydrogen ion concentration, pH 7-8.5; temporary carbonate hardness up to 5 mEq. / l. . It is proposed to use hot process water as the heat carrier, which satisfies the following requirements: carbonates — not more than 0.7 mg-squ. / Kg; hydrogen ion concentration. pH 7-8.5; residual total hardness to 0.05 mEq / kg. The choice of process water as a coolant and coolant is caused by the expediency of using it as a working agent in high-capacity refrigeration units currently being commercially produced, both because of environmental advantages and availability. However, in the general case, other working agents can be selected as the coolant and coolant. The method is most expediently carried out with the use of absorption refrigeration units, the principle of action of which is based on thermochemical reactions of absorption (absorption) of the working agent (process water) by the absorbent and separation (desorption) of the working agent from the absorbent. In the case when the working agent is process water with the indicated physical properties, it is advisable to use an aqueous solution of lithium bromide. Purpose of the refrigeration unit Cooling of the circulating refrigerant (process water) at 5-25 ° С The refrigerant is cooled by evaporating the condensed working agent (water) desorbed from the lithium bromide solution. Water desorption is performed by heating a solution of lithium bromide with a circulating coolant (hot water heated by low-grade heat of the gas product mixture). Calculations of a bromide-lithium refrigeration unit show that cooling of the circulating refrigerant at 5-25 ° C can be achieved at temperatures of the circulating heat sink. 105-130 ° C (hot water pressure at the same time -1.1-1.8 atm) The temperature of the circulating coolant decreases by 20-30 ° in this case. The correspondence between the decrease in the coolant temperature and the heat bodies is achieved through strict respectively Corollary sootnoscheni their costs .Raskhody depend on the type of the absorption aggregate and the performance of the catalytic reforming of the feedstock. Thus, at a catalytic reforming unit with a capacity of 1 mln.t / year, it is advisable to use a lithium-cooled refrigeration unit with a cooling capacity of 1 mln.kcal / h. In this case, the flow rate of the heat carrier is 80, and the chla agent is 200 m / h. The ratio of these costs (circulation ratio) is 80/200 0.4. The drawing is a diagram illustrating the catalytic reforming method. The gas product mixture through line 1 from the last reforming reactor enters the raw material heat exchanger cooled to 120-300 ° C, and then into the heat exchanger of the circulating heat carrier 3, additionally cooled to BO-ZOO C, the circulating heat carrier through line 4 enters the refrigerating unit 5 where it condenses, giving up its heat to generate cold. The resulting cold is used to cool the circulating refrigerant supplied through line 6 to 35-5 ° C. The heap of the optoduct mixture passed through heat exchangers 2 and 3 is condensed and successively cooled on an air-cooled condenser 7, a water cooler 8 and a circulating refrigerant heat exchanger 9 to 35-5 ° C. Since the temperature of the cooling water entering the cooler 8 through line 10 can vary depending on the season, the temperature of the separation mode is maintained by changing the circulation ratio of the coolant and coolant. Example 1. The gas product mixture 1 from the last reforming reactor with a temperature of 520 ° C enters the raw material heat exchanger 2, where it is cooled to 300 ° C and then cooled to 200 ° C in a heat exchanger of the circulating heat carrier 3. The heat carrier 4 is heated in a heat exchanger 3 from 100 up to 130 ° C and then it comes from the refrigeration unit 5, at the outlet of which a refrigerant 6 is obtained with a temperature of 5 ° C. Depending on the required separation mode, the flow rate of the streaks 4 and 6- can be changed. The gas product mixture after passing through the heat exchanger 3 is cooled successively in an air-cooled condenser 7 to 60 ° C, a water cooler 8 to 40 ° C and in a refrigerator of circulating refrigerant 9 to 5 ° C, while the refrigerant flow rate is 200 m / h (100% of the total quantities). Example 2. The temperature of gas product mixture 1 at the outlet of the last reforming reactor at 470 ° C. The gas-product mixture is successively cooled in apparatus 2, 3, 7, 8 and 9 to 120, 80, 60, 40 and 35 ° C, respectively. Paskhod coolant, as in example 1, 80 m / h, the refrigerant - 200. However, in this case, only part of the refrigerant (60% by weight) is passed through the heat exchanger 9 to maintain the separation temperature of 35 ° C, and the remaining part (40% by weight) is used for other technological purposes. The temperature IVP of the circulating refrigerant at the outlet of the refrigeration unit is 35 ° C. The temperature of the heat carrier 4 when it passes through the heat exchanger 3 varies from 85 to 105 ° C. Example 3. The data from the operation of the cat reformer is used. The gas product mixture at the outlet of the last reactor, MUHia, has a temperature of 482 ° C. It is sequentially cooled in the apparatus 2, 3, 7, 8 and 9 to 150, 120, 55, 35 and 25 ° C, respectively. The costs of the refrigerant and the coolant in the refrigeration unit are respectively 200 and 80 m / h. By analogy with example 2, only part of the refrigerant (80% by weight) passes through the heat exchanger 9 to maintain the separation temperature of 25 ° C, and the remaining part (20% by weight) is used for other technological purposes. The temperature of the circulating refrigerant at the outlet of the refrigeration unit is 20 ° C.

The temperature of the heat carrier 4 when it passes through the heat exchanger 3 varies from 100 to 120 ° C.

Lowering the separation temperature to 35–5 ° C (Examples 1–3) and stabilizing it over time allows maintaining the hydrogen concentration in the circulation gas at 75–85% by volume, while ensuring the stability of the unit operation regardless of the time of year.

The table shows the results of the comparison of the operation of the catalytic reforming unit according to the known and proposed methods.

493 493 493

Famous

81.7

The yoke of the lanyard of the table shows that, U) P ,, iOMbn), which allows you to increase 79, 5

0.8

3.0

100

28

38

Stabilize the / 1-D QUALITY k.ch 1 -;) sizer on average and 2.3 p-gi, viu-iniHTb 7 the duration of the inter-regeneration diqle for 3-4 months and as a result obtain an additional 2.5 wt.% P11formin1- gasoline. 1155613. 8 The excess cold produced at the facility can also be used for other technological purposes.

Claims (1)

METHOD FOR CATALYTIC REFORMING of a gasoline fraction in the presence of a hydrogen-containing gas in an adiabatic reactor, subsequent cooling of the gas-product mixture in a raw heat exchanger and a refrigerator and stabilization with the isolation of the target product, characterized in that, in order to reduce energy costs and increase the efficiency of the process, the gas-product mixture after The raw material heat exchanger is additionally cooled in the heat exchanger with a circulating heat carrier and, after the refrigerator, it is further cooled to 5-35 ° C with circulating coolant the agent and the heat of the circulating coolant after the heat exchanger are disposed of in a refrigerating machine to cool the circulating refrigerant to 5-35 ° C. „Oh, SU„ „1155613