DE1222615B - Process for regulating the preheating of the reaction participants in the catalytic cracking of gaseous or liquid hydrocarbons by means of steam - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. CL:

Number:
File number:
Registration day:
Display day:

Clog

German class: 26 a -12

1222615
K50652IVd / 26a
August 27, 1963
August 11, 1966

The invention relates to a method for controlling the preheating of the reactants in the catalytic splitting of gaseous or liquid hydrocarbons by means of water vapor and if necessary, air in the tube furnace.

In such a cracking method, the amount of fuel for heating the tube furnace is through the Determines the heat requirement of the cleavage reaction at the required gas generation capacity of the furnace. This Heat demand is the product of the specific heat demand of a reaction tube and the number of reaction tubes combined in a furnace. The specific heat demand of a Reaction tube, in turn, is the heat content difference of the substances introduced and discharged.

The amount of the heat content difference depends on various influencing factors, of which the most important are the heat of combustion of the heating gas, the specific gasification agent requirement, the cleavage temperature and the preheating temperature of the gasification agent are. Of all these sizes, only the last one is not predetermined while the rest, on the one hand, by the intended use of the gas to be generated and, on the other hand, by the reaction kinetic state in the cleavage are conditioned.

The latter can be the cause of processes (formation of soot or coke-like residues) through which an operation of the system as a result of a gradual but constant increase in gas pressure is made impossible in the reaction tube. These processes take place to a greater extent, such as the hydrocarbon used, high-boiling components or the gasification process from the outset Contains unfavorable influencing components. It is possible to partially get such adverse reactions to prevent that the reaction temperature at which the hydrocarbon is split is raised. From this point of view, the gap temperature must therefore be the same higher as the boiling point of the hydrocarbon is higher.

The compounds that interfere with operation are formed in particular in that part of the reaction tube in which the incoming reaction media are preheated to the temperature must, in which the water vapor can react with the hydrocarbons in the desired sense. It is therefore desirable that the selected operating conditions allow a quick rush through this critical one Allow temperature range. The residence time of the reaction mixture in this area

Procedure for regulating the preheating of the
Reactant in the catalytic
Splitting of gaseous or liquid
Hydrocarbons by means of water vapor

Applicant:

Heinrich Koppers

Company with limited liability,

Essen, Moltkestr. 29

Named as inventor:
Dipl.-Ing. Willi Rühl, Essen

but is all the shorter as the starting materials, especially water vapor and air, are introduced into the reaction tube at a high preheating temperature. The preheating of the starting materials to temperatures of about 600 to 800 ^° C. causes a reduction in the heat requirement in the reaction tubes and thus also a reduction in the amount of fuel for heating the reaction tubes. If the exhaust gas heat in the flue gas alone is not sufficient to cover the heat requirement of the steam generation at a preheating temperature of the starting materials of around 400 ⁰ C, this will be all the less the case at even higher preheating temperatures, since with the reduction in the amount of fuel also the The amount of smoke gas is less.

One could think of the gas generation capacity per reaction tube at an increased preheating temperature to increase. But there is a limit to this, since with such an increase in performance the The course of the reaction is adversely affected in the sense already mentioned above.

To solve this problem, the invention now proposes that the total of the splitting plant to be fed The amount of heat is divided into two controllable partial amounts, one of which is used to heat the Tube furnace and the other to increase the heat content of the flue gas after leaving the Tube furnace is used, with the generation of the water vapor required for the cleavage always exclusively by the flue gas and the preheating of the reactants to one for the one used Hydrocarbon optimal temperature level due to the production gas or production gas and flue gas takes place.

609 609/142

The distribution of the total amount of heat can be. train 15 of the steam boiler 8 enters. Before the steam

times are made by a partial boiler, part of the production gas is branched off

amount of the total required heating fuel and via line 16 to the heat exchanger 17

by means of an additional burner in which the one that is used to preheat the through line 18

Flue gas flow leaving the tube furnace is burned s supplied reaction air .and for overheating the

will. On the other hand, it is also possible to partially through line 19 from the steam boiler 8 with a

flow of flue gas with a higher temperature from a temperature of 150 ° C emerging water vapor

to be removed from the tube furnace and the one when serving. The heat exchanger 17 by conduit

heating of the tube furnace cooled down another 20 with 300 ⁰ C leaving production gas partial flow

Admix the flue gas partial flow. io is connected to the through line 21 from the boiler

In addition to the advantage of the pre-heating temperature of the coming together again and common-reactants, such as water vapor and air, are withdrawn from the system via line 22,
A part of the water-kinetic conditions generated in the steam boiler 8 are present in the can, steam is fed as heating steam through line 23 to a second heat exchanger 24, in which the Favorable size of the individual parts of the gasoline coming in through line 25, whereby, for example, the steam boiler is preheated or partially evaporated to 140 ° C, to which the water vapor required for the process The condensate outlet is denoted by 26,
is generated, always exclusively from the hot A preheating of the boiler feed water, the flue gases flows through and due to higher 20 through line 27 is fed to the steam boiler 8, flue gas temperatures at the boiler inlet than derjen- is not provided here.

gene in the known tube fission systems in its with the waste heat in the production gas as well

Size can be kept smaller. In the flue gas, the heat requirement must be both the

The invention is now to be covered with reference to the drawing, steam generation and the preheating in Fig. 1, a splitting system according to the previous 25 of steam and air. In FIG. 2 and in FIG. 2, a cracking plant according to the new conventional procedure described above shows how it is operated, while at the same time specifying one thing, the result is that the heat coefficient example is not explained in more detail at the same time. required for the generation of water vapor by the

In both systems, gasoline should boil with flue gas heat or through the waste heat in the

At the end of about 180 ° C with steam and air ₃₀ production gas all covered and on the other hand one

catalytically to a standard-compliant town gas preheating temperature for reaction steam and reac-

will split. With an output of the systems of air conditioning above 400 ° C can be achieved.

50,000 Nm ³ per day are the following starting materials for steam generation is namely at

required: the above gas generating capacity, one

Split fuel 685 kg / hour ^{35 W} ^ inh ^a lt of the saturated steam of 668.7 kcal / kg and

^{F &} an efficiency of steam generation of

Water vapor (20 atü) 1918 kg / hour 95% a heat supply of 1.35 · 10e kcal / hour. loading

Reaction air 215 NmVh. ¹¹⁰⁰ St- ^{From the} waste heat of the flue gas be

but carries the heat supply with a boiler

Gasoline 276 kg / hour ₄₀ entry temperature of 300 ° C only 0.948 106 kcal / hour,

Combustion air 3510 Nm ³ / hour and from the heat of degradation of moist production

gases only 0.65 · 10 ⁶ kcal / h. This results in

Fuel and combustion air get according to Fig. 1 inevitably that a part of the smoke tubes through the lines 1 and 2 to one or more steam boiler with production gas and another xen burners 3 of the tubular furnace 4. The 45 part with flue gas must be applied.
combustion of the heating gasoline released heat A regulation of the heat flow and a heat exchange surface of the external increase in the preheating temperature of about 400 ° C, heated, catalyst-filled cans 5 to which the reaction mixture of refinery gas flowing past the natural gas or the catalyst, for example, is sufficient , to 600 to 800 ° C, and covers the heat consumption of the 50 as it depends on the boiling point and the content of the cleavage reaction. Thereby 3435 Nm ^s / h fall. Moisturized ring-shaped and unsaturated compounds appear in the flue gas. After heat transfer to the cleavage of the cleavage of high-boiling hydrocarbons tubes leaves the flue gas at a temperature for the purpose of rapid transit Eilens critical, PoIyvon 965 ⁰ C the tube furnace by the flue gas polymerizations favorable temperature range, exits 6 and is passed via line 7 to the 20-atm-steam 55 in the upper part of the catalyst bed to strive for boiler 8 fed, which it is through the boiler pass 9, is not possible.

flows through. It occurs with a temperature of In F i g. 2, in FIG. 1 corresponding plant

300 ° C through line 10 from the boiler and parts with the same mark, are now provided is discharged through a chimney, not shown. the procedure according to the invention illustrate the Cracked petrol arrives at an operating temperature of 60.

temperature of 140 ⁰ C through line 11, steam supplied through line 1 Heizbenzin.wird

and reaction air with temperatures of 400 ⁰ C divided into two partial quantities, one of which, through the lines 12 and 13 into the cans 5, larger ones, through line 30 to the burner 3 of the Röhin where it reaches a standard-compliant renofens 8 on the catalyst and here with air from line 2 town gas, hereinafter referred to as production gas, is burned. The other partial amount of gasoline flows to be converted. The outlet temperature of the production gas from the tube furnace through line 31 to an additional burner 32 is in the flue gas line 7 behind the tube furnace, where 785 ° C, with which it is through line 14 into the boiler- the combustion of the gasoline with combustion air from line-

device 33 takes place. According to the division of the entire Heizbenzinmenge so flue gas temperatures between 965 and about 1400 ⁰ C can be set.

The regulation of the flue gas outlet temperature can alternatively also be carried out in such a way that one all of the fuel burns in the burner 3, but some of the flue gas that spreads through Heat exchange with the reaction tubes 5 has not yet cooled or only partially cooled by a special flue gas outlet 34 withdraws and through line 35 the tubular furnace through flue gas outlet 6 and line 7 leaving the flue gas stream admixed. This possibility is shown in FIG. 2 dashed drawn.

Since flue gas, for example, a temperature of 1160 ° C, has now both trains durchtrömt 9 and 15 of the steam boiler and is then again cooled to 300 ⁰ C, at which temperature it is discharged through conduit 10 degrees. ao

The entire production gas at 785 ° C. is thus available in the heat exchanger 17 for preheating the reaction media water vapor and air. This makes it possible to raise the temperature to 700 ⁰ C. The heat exchanger 17 is yet another heat exchanger 36 downstream to preheat the boiler water on Food 8O ⁰ C, entering through line 31 and passes through line 27 to the boiler. The production gas flows into this heat exchanger at a temperature of 300 ^° C. through line 38 and leaves it through line 22.

As with the method according to FIG. 1 also takes place here in the preheating of the mineral spirits Heat exchanger 24 by means of heating steam from line 23 instead.

With a fuel consumption of the tube furnace of a total of 276 kg / hour. for the gas generator power mentioned at the beginning is achieved by dividing the amount of fuel gas according to the invention between the head and the outlet of the tube furnace, namely 226 kg / hour at the top of the furnace. and at the flue gas outlet 50 kg / hour.

burned, the flue gas outlet temperature increased from 965 to 1160 ° C and thus the heat requirement for the steam generation exclusively from flue gas heat of 1.35 · ⁶ kcal / hour. covered. At the same time, the preheating temperature for steam and reaction air can be increased to 700 ° C.

Claims (2)

Patent claims: 1. Process for regulating the preheating of the reactants in the catalytic Splitting of gaseous or liquid hydrocarbons by means of water vapor and, if necessary, Air in the tube furnace, characterized in that the total amount of heat to be supplied to the splitting system can be regulated in two Partial quantities are broken down, one of which is used to heat the tube furnace and the other is used to increase the heat content of the flue gas after leaving the tube furnace, the Generation of the water vapor required for the cleavage always exclusively by the Flue gas and the preheating of the reactants to one for each used Hydrocarbon optimal temperature level due to the production gas or production gas and flue gas. 2. The method according to claim 1, characterized in that the increase in the heat content of the flue gas leaving the tube furnace either by additional burning a subset of the total required heating fuel by means of a burner or by Extraction of a partial flow of flue gas at a higher temperature from the tube furnace and mixing to the other flue gas partial flow that is cooled during the heating of the tubular furnace. Considered publications:
Ulimann, "Encyclopedia of Industrial Chemistry", Vol. 1 (1951), p. 274. 1 sheet of drawings 609 609/142 8.66 © Bundesdruckerei Berlin