SU1545946A3 - Method of producing hydrocarbon fuel and pitch - Google Patents

Abstract

A petroleum type heavy oil is fed from a heating furnace into a first reactor. After termination of the first reaction, the reaction prod. is fed into a second reactor. The reaction prod. is fed continuously into the next reactor in order. At the sametime, the temp. of a liquor in the reactor is raised in such a manner that it ranges between Tl=440-90 exp (-0.085 theta) and Tl=400-100exp(-0.085 theta) [Tl=liq. phase temp.; theta is time (min) . The process is used for thermal cracking of petroleumtype heavy oil.

Description

RED. tanks - and in the case of the presence of at least three reaction tanks - continuous supply of preheated heavy diesel fuel from the tubular heater to the corresponding subsequent reaction tanks, simultaneously introducing superheated up to 400-75 ° C steam at contact time of 30-300 minutes. The temperature of the liquid petal of heavy diesel fuel in the reaction tanks is maintained during the loading of this fuel from the tubular heater into the reaction tank between T and Tj, where T1 and T are respectively determined by the formulas

t, 400-100 exp (-0.085e); ()

t 440 - 90 exp (-0.085v).

(2)

where at the time from the start of loading preheated heavy diesel fuel, min; T is the temperature of the liquid product in the reaction tank, CC.

The quality of heavy diesel fuel used as feedstock in the invention may be residual oils from distillation at atmospheric or reduced pressures and residual thermal cracking oils. Thermal cracking of heavy diesel fuel is carried out in a system that includes tubular heaters and many reaction vessels of the same size and design.

FIG. I shows the temperature of the liquid phase in the reaction vessel as a function of time in FIG. 2 is the flow rate of superheated steam blown into the reaction tank as a function of time, with p being the maximum flow rate.

The method for increasing the temperature of the liquid phase in the reaction vessel is maintained at a specified level, as in, for example, FIG. I, where the temperature of the liquid phase in the reaction tank is plotted along the ordinate axis, and the time from the start of loading the remaining main part of heavy diesel fuel - along the axis of the abyss.

In particular, curve 1 (Lig. 1) illustrates the change in the temperature of the bulk phase in the reaction tank

five

0

five

0

five

0

five

0

five

over time (i.e., the nature of the temperature and decrease in the temperature of the liquid phase) in one cycle of the proposed method (example l) and, as can be seen from curves 1, T and IT, the temperature of the liquid phase is maintained between T and T at any moment the time from the start of loading the remaining main part of heavy diesel fuel to the end of loading, while curves I and II correspond to formulas (1) and (2). A similar position along curve 2, illustrating the change in T over time in the experience of Example 2.

As a result of maintaining T in the specified range between T and T., during the process of loading the remainder of the heavy diesel fuel into the reaction tank and after loading, the aim of the invention is achieved, namely, to obtain cracking fuel of favorable quality with the maximum possible output together with obtaining homogeneous pitch with favorable properties in terms of coke formation and with the lowest possible quantitatively layer of coke in the reaction tank and thus in ensuring long Resistant plant operation for thermal cracking of heavy diesel fuel (tab. 2 and 3, Examples 1 and 2). Cracking fuel obtained by the proposed method, rich in aliphatic hydrocarbons and, accordingly, suitable as fuel oil.

In the case when T is not maintained between T1 and Tlf, in particular, at an early stage of loading the remaining main part of heavy diesel fuel, namely maintaining the increasing character of T, is violated as a result of some erroneous regulation of these factors, the following result is obtained.

Curve 3 (Fig. 1), representing the change in TL (° C) in Comparative Example 2 over time, deviates downward from curve I, which characterizes the change over time, in particular at an early loading stage, as a result of adjusting these factors compared to the adjustment results in comparative example 2 (Table I), the yield of cracking fuel is lower than in examples I and 2, although the quality of the pitch is almost

one

the same as for example 1– and 2, and the results demonstrate a more advanced industrial level in comparative example 2, taking into account the cost of cracking fuel and a huge amount of heavy diesel fuel subjected to thermal cracking on an industrial scale production.

In the last thermal cracking stage, the pitch formed by the liquid phase of the reaction tank is periodically sampled for analysis to measure its softening temperature, and at the time when the softening point of the pitch sample reaches

at a predetermined level, the contents of the reaction vessel are cooled by mixing with a cold product to stop thermal cracking.

The proposed method yields a greater amount of cracking fuel with favorable properties in the form of fuel oil and more homogeneous pitch with long-term stable operation of the thermal cracking unit due to the use of two tubular heaters and two reaction tanks continuously and sequentially, alternately, without the formation of a significant amount of coke in the reaction tank.

Example 1 A mixture of residual oil, obtained by distilling oil under reduced pressure, and residual oil, obtained by distilling oil under reduced pressure, having beats. weight (15 ° C / 4 ° C) 1.023, is used as a raw material, having the following composition, wt.%: residual carbon Couradson 22.3; ash 0.14; sulfur 4.25; nitrogen 0,48.

Raw materials (heavy diesel fuel stored in a tank heated to 150 ° C are heated in a device containing two tubular heaters and two reaction tanks (each with an inner diameter of 300 mm and a height of 2000 mm) equipped with a rotating stirrer at 50 rpm (Fig. 3, where the technological scheme of the proposed method is shown), under the conditions given in Table 1

In particular, 8.2 kg of raw materials corresponding to the part of the raw material subjected to thermal cracking for one cycle in one of the reaction mixtures.

9466

tanks entered by speed

flow (1 .40 kg / hr. as the initial load into the first reaction tank through the first tubular heater, where the initial load is preheated to 327SS. After that, the amount of raw material corresponding to the core of the main part of the raw material subjected to thermal cracking for one cycle in the reaction tank is sent from the tank to the first reaction tank at a rate of

r feed 38 kg / h for 120 min through the second tubular heater, where the raw material is heated to 490 ° C.

Simultaneously with the start of loading the main part of the raw material is superheated

0 water vapor with a temperature of approximately 690 ° C and a pressure of 8 kgf / cm7 (0.8 MPa) is introduced into the first reaction tank through its bottom part while simultaneously observing the specified technological program

(Fig. 2), as a result, the thermal cracking of the raw material that has already been started is accelerated, and the cracking gas is removed from the first reaction vessel

Q together with water vapor. In this way, the cracked gaseous product (cracking gas) is converted into cracking fuel and a high boiling fraction in a separate unit, while the high boiling fraction is sent to the second tubular heater as a riser after it is biased with the feedstock.

The introduction of superheated steam is continued until the softening temperature of the material leaving the first reaction tank (pitch) reaches 185 ° C within the specified range of 184 - 187 ° C, then the pitch is rapidly mixed with cold product (quenching) and withdrawn from the first reaction vessel.

The nature of the change in the temperature of the liquid phase in the first reaction tank in time is shown in curve 1 (Fig. 1) from the start of loading the main part of the raw material to the end of the pitch separation.

After completion of loading the main part of the raw material into the first reaction tank, the same technological operations for commissioning the first charge and inputting the main part of the raw material

0

at a second reaction cycle, during the second cycle, and after the separation of the pitch from the first reaction tank has been completed, it is transferred to chapas until the next cycle (trty cycle) is used (in the device).

In particular, the thermal cracking of heavy diesel fuel in the device is carried out continuously alternately using one of the reaction tanks.

The material balance and physical properties of the pitch thus obtained, as well as the thickness of the coke layer formed in the first reaction tank during thermal cracking from the pitch, are presented in Table. 2 and 3 respectively.

Example 2. The same raw material is subjected to thermal cracking as in example 1, except for the operating conditions given in table. 1. The nature of the change in the temperature of the liquid phase in the first reaction tank is shown as curve 2 (Fig. 1), and the results of thermal cracking are shown in Table. 2 and 3.

Examples 1 and 2 (comparative). The same raw material as in example 1 is subjected to thermal cracking in the same device, which is also in examples 1 and 2 under the appropriate operating conditions (Table 2, examples 1 and 2, respectively).

Despite the fact that the working conditions in comparative examples 1 and 2 are almost identical with the conditions in examples 1 and 2, the temperature variations of the liquid phase in the reaction tank in time in comparative examples 1 (curve 3) and 2 (curve 4) are typical. they differ from one another and, moreover, from examples 1 and 2, respectively, in connection with the difference in operating conditions, including the indicated factors.

The results of comparative examples 1 and 2 are also presented in table. 2 and 3 for comparison with the results of examples 1 and 2.

Example 3. The same raw material is subjected to thermal cracking in example 1 for a cg-key. 1 (example H).

five

0

five

0

five

0

five

0

five

The change in the temperature of the liquid phase in the first reaction vessel over time is shown in FIG. 4 (curve 5) from the start of loading the main part of the raw material to the completion of the black resin recovery.

Examples A and 5. The same raw material is subjected to thermal cracking in the same manner as in Example 1, except for the following operating conditions shown in Table 2. 1. A graph of the temperature change of the liquid phase in the first reaction vessel is shown in FIG. 5 in the form of curves 6 and 7, and the results of thermal cracking - in Table. 2 and 3.

In comparative example 1 (Table 3), the temperature of the liquid phase in the first reaction tank (Fig. 1, curve 3) during the loading of the main part of the raw material is higher than the temperature defined by formula (2) and is characterized by the TI curve (Fig. 1) from the start of loading due to a violation in the regulation of these factors (Table 1), the content of the quinoline-insoluble component in the resulting pitch is larger and the size of the optically anisotropic substance dispersed in the pitch (mesophase) is larger than in the pitch obtained in examples 1 and 2, where liquid phase temperature in primary The reaction tank is maintained between T and T7, defined by formulas (l) and (2), respectively, due to the regulation of the indicated factors (Table 2). The results shown in the properties of the pitch obtained in comparative example 1 indicate that the pitch is much more heterogeneous, and taking into account the thickness of the coke layer formed from the pitch in the reaction tank, the long-term stable operation of the thermal cracking unit of heavy diesel fuel has not been proven under operating conditions of Comparative Example 1 in the same reaction vessel.

On the other hand, although in comparative example 2, there are no problems with regard to the properties of the pitch obtained in comparative example 1, where the temperature of the liquid phase in the reaction tank (Fig. 1, curve A) is lower than the temperature determined by formula (1) and illustrated curve 1 at least from

the beginning of the main part of the raw material pods, due to a violation in the regulation of the above factors (Table 1), the yield of cracking fuel in comparative example 2 is lower than in examples 1 and 2 by approximately 2% by weight.

Claims (1)

Invention Formula The method of producing hydrocarbon fuel and pitch by thermal cracking of heavy diesel fuel, including preheating the feedstock to 460-505 C in a tubular heater for 245- 605 s, feeding the heated liquid product into the first reaction tank with simultaneous introduction of superheated to 400- 750 ° C of water vapor in its bottom part when they are in direct contact for 30-300 minutes with the formation of a pitch and separation of liquid product and subsequent three-stage processing it in a tubular heater and reaction vessel under similar conditions, tl and h and PI and the fact that, in order to improve the quality of the pitch, the process is carried out by regulating at each stage the temperature of the heated liquid product when it is supplied from the tubular heater to the reaction tank so that it is between T and T, defined by the following formulas T1 400 - IOO exp (-0.085b); T 440 - 90 exp (-0.085b) / where at - time from the start of loading 20 pre-heated liquid product, min; T is the temperature of the liquid product At the exit of the first pipe heater. Ea output of the second tubular preheater. I Table I Reaction conditions Material balance The properties of the black resin and the thickness of the coke residue in the reaction vessel The softening point, ° С The content of quinoline-insoluble components, wt.% Size of optically anisotropic bodies, micron thick coking layer, mm 185184185185 186186 186 18,017,717,018.2 17,819.0 16.7 50-10040-8030-4070-100 40-90200-1000 30-50 1.00.3 C, 71.0 0.92.2 0.7 0 as defined in Japan Industrial Standards (PSL) K-7210. 0 as defined in Japan Industrial Standards (PSL) K-2425. Determined by microscope. I54594G 12 Table 2 Table 3 about ui r .. "l fe § wnt, O0 vdfiwodauHaji “R“ x “ose A / $ x poxwd Oida loading time I open saepyttu PK0Z gcho Wren reaction. J  1va .G A- "  iiImpmzre ff / W