ELECTRICALLY HEATED, HYBRID HIGH-TEMPERATURE METHOD

Abstract

A method of continuously performing one or more heat-consuming processes, where at least one heat-consuming process is electrically heated. The maximum temperature in the reaction zone of the heat-consuming process is higher than 500° C., at least 70% of products of the heat-consuming process are continuously processed further downstream and/or fed to a local energy carrier network, and the electrical energy required for the heat-consuming process is drawn from an external power grid and from at least one local power source. The local power source is fed by at least one local energy carrier network and by products from the heat-consuming process. The local energy carrier network stores natural gas, naphtha, hydrogen, synthesis gas, and/or steam as energy carrier, and has a total capacity of at least 5 GWh. The local energy carrier network is fed with at least one further product and/or by-product from at least one further chemical process.

Claims

1-14. (canceled).

15. A method of continuously performing at least one heat-consuming chemical process of a chemical site obtaining hydrogen, the method comprising: drawing electrical energy required for at least one heat-consuming process from an external power grid and from at least one local power source, feeding the at least one local power source from at least one local energy carrier network, to an extent of at least 50% of annual energy demand of the at least one local power source, feeding said at least one local power source with hydrogen that comes directly from the at least one heat-consuming process, to an extent of not more than 50% of annual energy demand of the at least one local power source, storing hydrogen from the at least one heat-consuming process as an energy carrier in the at least one local energy carrier network, and feeding a local hydrogen network with hydrogen from at least one further chemical process; wherein the at least one heat-consuming process is electrically heated, the maximum temperature in a reaction zone of the at least one heat-consuming process is higher than 500° C., and at least 50% of hydrogen of the at least one heat-consuming process is continuously processed further via a product conduit in downstream processes and via a conduit supplied to the local hydrogen network, and wherein a total capacity of the local hydrogen network is at least 5 GWh.

16. The method according to claim 15, wherein the at least one local energy carrier network comprises at least two different local energy carrier networks, and wherein one of the at least two different local energy carrier networks stores natural gas, naphtha, synthesis gas, or steam as an energy carrier.

17. The method according to claim 15, wherein the hydrogen from the at least one heat-consuming process as the energy carrier in the at least one local hydrogen network is distributed via associated pipe grids and storage vessels.

18. The method according to claim. i5, wherein the at least one local energy carrier network has a total capacity of at least 20 GWh.

19. The method according to claim 15, wherein the local hydrogen network is fed from a process selected from the group consisting of steamcracking, steam reforming, methane pyrolysis, styrene synthesis, propane dehydrogenation, synthesis gas production, and formaldehyde synthesis.

20. The method according to claim 15, wherein the at least one local power source is a gas turbine, a steam turbine, and/or a fuel cell.

21. The method according to claim 15, wherein the energy required by the at least one heat-consuming process is provided by electrical energy to an extent of at least 90%.

22. The method according to claim 15, wherein the at least one heat-consuming process is performed on an integrated site.

23. The method according to claim 15, wherein the at least one local power source has a startup time of shorter than 15 minutes.

24. The method according to claim 15, wherein a reactor used for the at least one heat-consuming process comprises a random packing of solid particles of electrically conductive material.

25. The method according to claim 24, wherein the at least one heat-consuming process is performed in a moving bed with countercurrent flow of a solid-state stream and a gas stream, and wherein the moving bed has a volume-specific heat capacity of 300 kJ/(m.sup.3 K) to 5000 kJ/(m.sup.3 K).

26. The method according to claim 15, wherein tapping from the external power grid and switching-on and -off of the at least one local power source is controlled depending on cost of power.

27. The method according to claim 15, wherein the at least one heat-consuming process is steam reforming, dry reforming, thermolysis of water, pyrolysis of hydrocarbons, and/or cracking of hydrocarbons.

28. The method according to claim 15, wherein the method provides minute reserve for a public power grid.

29. A method of storage of electrical energy, the method comprising: storing electrical energy through a local hydrogen network of a chemical site, wherein hydrogen from an electrically heated heat-consuming process and hydrogen from at least one further chemical process is fed and stored in the local hydrogen network, and wherein the local hydrogen network has a total capacity of at least 5 GWh.

Description

EXAMPLES

[0224] FIG. 1 shows a schematic of a variant of the method of the invention with a directly resistance-heated fluidized bed reactor, an inductively heated fixed bed reactor, and an indirectly resistance-heated fixed bed reactor on an integrated site. Each process is fed with electrical energy both from the public power grid and from a respective local power source.

[0225] FIG. 2 shows a scheme of the comparative process according to the prior art. The internal power source is a combined cycle power plant with steam export that has the highest efficiencies among the conventional power plants. The steam turbine is connected directly to the waste heat tank of the gas turbine generator. The response behavior of the steam turbine is determined by the inertness of the waste heat tank of the gas turbine.

[0226] FIG. 3 shows a scheme of the process of the invention. The internal power source consists—identically to the combined cycle power plant—of a gas turbine generator and a steam turbine generator. The steam turbine is not connected directly to the waste heat tank of the gas turbine but to the steam grid of an integrated site. As a result, it is possible for the steam turbine to react to changing load virtually without delay.

[0227] FIG. 4 shows a scheme of the process of the invention. The heat-consuming process is fed from the public power grid and from local power sources. The local power sources are supplied with energy carriers from the integrated system grid. The integrated system grid stores energy carriers that are generated in the heat-consuming process and/or other processes within the integrated system. The main products of the heat-consuming process are fed to a downstream process within the integrated system.

[0228] FIG. 5 shows a scheme of the process of the invention. The heat-consuming process is fed from the public power grid and from a local power source. The local power source is supplied with steam from the integrated system grid. Hydrogen obtained as a by-product from the heat-consuming process is stored in the integrated system grid. The local power source is driven by means of a steam turbine generator. The hydrogen for the purpose is drawn from the integrated system grid. The main products of the heat-consuming process are fed to a downstream process within the integrated system.

LEGEND

[0229] 1 Electrically heated heat-consuming process

[0230] 2 Separation apparatus for removal of the main products and by-products of the heat-consuming process

[0231] 3 Integrated site grid for steam

[0232] 4 Integrated site grid for hydrogen

[0233] 5 Integrated site grid for natural gas

[0234] 6 Conduit for hydrogen-containing gas stream

[0235] 7 Steam conduit

[0236] 10a Conduit for supply of an internal power source with steam

[0237] 10b Conduit for supply of an internal power source with hydrogen

[0238] 10c Conduit for supply of an internal power source with natural gas

[0239] 11a Internal power source driven with steam

[0240] 11b Internal power source driven with hydrogen

[0241] 11c Internal power source driven with natural gas

[0242] 12a Power line from the steam-driven power source to the heat-consuming process

[0243] 12b Power line from the hydrogen-driven power source to the heat-consuming process

[0244] 12c Power line from the natural gas-driven power source to the heat-consuming process

[0245] 16 Public power grid

[0246] 17 Product conduit for the transport of the main products from the heat-consuming process to a downstream process

[0247] 20 Power line for feeding of electrical power from the public grid into the heat-consuming process

[0248] 21 Busbar for feeding of electrical power from the internal power sources into the heat-consuming process

[0249] 31 Further process within the integrated system

[0250] 32 Separation apparatus in the further process within the integrated system that removes energy carriers and introduces them into the integrated system grid

[0251] 36 Conduit for hydrogen-containing gas stream from the further process within the integrated system

[0252] 37 Steam conduit from the further process within the integrated system

[0253] 51 Downstream process of the heat-consuming process within the integrated system

Example 2

[0254] Comparative Process 1: Combined Cycle Power Plant

Combined cycle: CH.sub.4+2O.sub.2.fwdarw.CO.sub.2+2H.sub.2O+481kJ.sub.el/mol  (1)

[0255] By this process, it is possible to generate electrical power from natural gas, a raw material on the integrated site, in a local power source in accordance with demand, A combined cycle generator generates 481 kJ of electrical energy per mole of methane used. At the same time, one mole of CO.sub.2 is emitted. However, this process is unsuitable for storing surplus electrical energy from the grid.

[0256] Comparative Process 2: Renewable Energy in Electrolysis to Hydrogen/Reconversion in the Fuel Cell to Electrical Energy

ReGen+EL: H.sub.2O.sub.(l)+(1/75%*286) kJ.sub.el/mol.fwdarw.H.sub.2+½O.sub.2  (2)

AFC: H.sub.2+½O.sub.2.fwdarw.H.sub.2O.sub.(l)+(70%*237) kJ.sub.el/mol  (3)

ReGen+EL+AFC: 381 kJ.sub.el/mol.fwdarw.166 kJ.sub.el/mol  (4)

[0257] By this process, it is possible to use electrical energy from the power grid for the production of hydrogen. The hydrogen can be fed into the pipeline grid of the integrated site. The hydrogen can be utilized physically or, if required, converted back to electrical power in a local fuel cell. About 0.44 kJ of electrical energy can be recovered per kJ of electrical energy fed into this process. This amount of electrical energy is free of CO.sub.2 emissions.

[0258] Comparative Process 3: Combination of Combined Cycle and Electrolysis/Fuel Cell

ReGen+EL+AFC+CCPP: CH4+2O.sub.2+92 kJ.sub.el/mol.fwdarw.CO.sub.2+2H.sub.2O+521.5 kJ.sub.el/mol  (5)

[0259] Process of the invention: Combination of methane pyrolysis and hydrogen-driven power source

ReGen+MePy: CH.sub.4+(74.8/81.3%) kJ.sub.elmol.fwdarw.C.sub.(s)+2H.sub.2  (6)

AFC: 2H.sub.2+O.sub.2.fwdarw.2H2O.sub.(l)+(70%*474) kJ.sub.el/mol  (7)

GT+ST: 2H.sub.2+O.sub.2.fwdarw.2H.sub.2O(g)+(60%*484) kJ.sub.elmol  (8)

ReGen+MePy+AFC: CH.sub.4+O.sub.2+(74.8/81.3%) kJ.sub.el/mol.fwdarw.C.sub.(s)+H2O.sub.(l)+332 kJ.sub.el/mol  (9)

Regen+MePy+(GT+ST): CH.sub.4l+O.sub.2+(74.8/81.3%) kJ.sub.el/mol.fwdarw.C.sub.(s)+H2O.sub.(g)+290 kJ.sub.el/mol  (10)

COPP: C.sub.(s)+O.sub.2.fwdarw.CO.sub.2+(45%*393) kJ.sub.el/mol  (11)

ReGen+MePy+AFC+COPP: CH.sub.4+2O.sub.2+(74.8/81.3%)kJ.sub.el/mol.fwdarw.CO.sub.2+2H.sub.2O+509kJ.sub.el/mol  (12)

ReGen+MePy+(GT+ST)+COPP: CH.sub.4+2O.sub.2+92 kJ.sub.el/mol.fwdarw.CO.sub.2+2H.sub.2O+467 kJ.sub.el/mol  (13)

[0260] Surplus energy from renewable sources available in the external power grid is utilized for the operation of a plant for methane pyrolysis (eq. 6), The thermal efficiency of the pyrolysis based on the standard enthalpy of reaction is 81.3%. The hydrogen produced is fed into the supply grid of the integrated site. It can be utilized physically or energetically therein. The carbon produced is highly pure, inert and free-flowing. For instance, it can be transported and physically utilized or deposited in landfill. In accordance with demand, the hydrogen, simultaneously or at a different time from its production, is used for power generation in an AFC with 70% voltage efficiency (eq. 7) or in a combined gas turbine and steam turbine generator having a thermal efficiency of 60% (eq. 8). Each kilojoule of electrical energy from the external power grid which is fed into the methane pyrolysis, by virtue of the conversion of the hydrogen produced to power, depending on the local power source, can become about 3.1 kJ to 3.6 kJ of electrical energy (eqs. 9, 10) virtually free of CO.sub.2 emissions. By comparison with the storage of electrical energy according to the prior art in an electrolysis fuel cell circuit, the method of the invention, through the use of methane, generates six to eight times the amount of electrical energy free of CO.sub.2 emissions.

[0261] Some of the chemical energy present in the methane remains stored in the carbon coproduct and can be converted to power in a conventional thermal power plant—accompanied by CO.sub.2 emissions (eq. 11). If the use of the carbon for energy purposes is allowed, the amount of electrical energy which is produced by the process consisting of methane pyrolysis with external surplus power and conversion of the hydrogen and carbon produced to power, is about 97% to 106% of the electrical energy produced by a combined cycle power plant according to the prior art with the same methane conversion (eqs. 1, 12, 13). The possible surplus in the method of the invention results from utilization of the electrical power from the external grid in methane pyrolysis.

[0262] Taking account of the total input of mass and energy, the amount of electrical energy which is produced by the method of the invention is about 90% to 98% of the electrical energy produced by a process consisting of an electrolysis/fuel cell circuit and a combined cycle power plant (eqs. 5, 12, 13).

[0263] The essential advantage of the invention is that it is possible to utilize imported electrical energy in order to use the internal power sources to produce a multiple of electrical energy free of CO.sub.2 emissions.

TABLE-US-00003 Feed Electrical energy in kJ.sub.el CO.sub.2 Process Methane used.sup.(2a) generated.sup.(2b) storable.sup.(2c) emission Comparative 1 mol  0 481  0 1 mol process 1 Comparative 0 92  40 40 0 process 2.sup.(1) Comparative 1 mol 92 521 40 1 mol process 3 Process of the 1 mol 92 290-332 290-332 0 invention Process of the 1 mol 92 467-509 467-509 1 mol invention + conversion of C to power .sup.(1)The amounts of mass and energy in eq. 2, eq. 3 and eq. 4 have been scaled such that the amounts of electrical energy imported in the comparative process and in the process of the invention are identical. As a result, the numerical values are directly comparable with one another. .sup.(2a)The amount of electrical energy used indicates the amount of energy based on 1 mol of methane which is imported into the integrated system from the external power grid. .sup.(2b)The amount of electrical energy generated indicates the amount of energy based on 1 mol of methane which can be generated in the local power grid from the methane used and the electrical energy used beforehand, or the products produced therefrom. .sup.(2c)The amount of storabie electrical energy indicates the amount of energy based on 1 mol of methane that can be generated in the local power grid from products that have been produced in the integrated system with the electrical energy used beforehand.

[0264] Legend

AFC: alkaline fuel cell
CC: combustion chamber
ST: steam turbine
EL: electrolysis
G: generator
GT: gas turbine
CCPP: combined cycle power plant
HP steam: high-pressure steam
COPP: coal-operated thermal power plant
MePy: methane pyrolysis
LP steam: low-pressure steam
ReGen: power from renewable energy source
TPP: thermal power plant
CM: compressor
DM water: feed water for the waste heat boiler of the gas turbine