Method for controlling a heat-consuming hydrocarbon conversion process

A method for controlling a process carried out in an integrated production plant, wherein the integrated production plant comprises:

• (1) supply means MF for providing one or more hydrocarbon feed streams SF to a unit UC for heat-consuming hydrocarbon conversion to obtain from UC one or more product streams S and a light hydrocarbon conversion off-gas stream SO comprising CH4;
• (2) the unit UC which comprises heating means MH for providing heat to the hydrocarbon conversion, wherein said heating means MH comprise means for generating heat from one or more heat sources HS and wherein said one or more heat sources HS comprise H2;
• (3) controllable supply means ME for providing one or more plant-external sustainable heat sources HEXT-S, one or more plant-external fossil heat sources HEXT-F, and one or more plant-internal heat sources HINT, said plant-internal heat sources HINT comprising H2, for passing at least one of said heat sources HEXT-S, HEXT-F and HINT to the heating means MH;
• (4) a reforming unit UR for subjecting the light hydrocarbon conversion off-gas stream SO to reforming to obtain a product gas stream SR comprising CO and H2;
• (5) a controllable processing unit UP for processing SR or a part stream S′R thereof to obtain a stream SH being enriched in H2 compared to SR or S′R;
• and
• (6) and optionally comprises controllable supply means MR for optionally dividing the stream SR into the part stream S′R and a stream S″R, and for passing S′R into UP;
• wherein the process comprises:
• (i) passing one or more heat sources according to (3) from ME to MH in an amount sufficient for generating heat in MH meeting the heat demand EUC of the hydrocarbon conversion in UC;
• (ii) passing at least one hydrocarbon feed stream SF into UC and subjecting the at least one feed stream SF to hydrocarbon conversion in UC, obtaining the one or more product streams S and SO;
• and
• (iii) passing SO into UR and subjecting SO to reforming in UR, obtaining SR;
• wherein the method for controlling the process comprises:
• (a) determining the heat demand EUC of the hydrocarbon conversion in UC to be provided by MH;
• (b) determining the amount EEXT-S of heat available for UC from the one or more plant-external sustainable heat sources HEXT-S;
• and
• (c) determining ΔE=EUC−EEXT-S and
• (c.1) if ΔE>0,
• (c.1.1) determining H2N, the amount of H2 necessary to produce ΔE in MH;
• (c.1.2) determining H2P, the maximum amount of H2, producible in UR and UP to be contained in SH, to produce an amount EH2P of heat in MH;
• (c.1.3) determining ΔH=H2N−H2P;
• and
• (c.1.3.1) if ΔH>0,
• controlling the processing unit UP, the supply means ME and optionally the supply means MR so that H2P is passed into MH via SH;
• wherein the process further comprises:
• (iv) optionally passing SR obtained from UR through MR, obtaining a stream S′R being x volume-% of SR, with x=100;
• (v) passing the stream SR or, if (iv) is carried out, the stream S′R into UP, obtaining SH;
• (vi) passing the stream SH obtained from UP through ME, obtaining a stream S′H being y volume-% of SH, with y=100;
• (vii) passing the stream S′H obtained from ME as HINT into MH;
• and
• (viii) passing at least one of the one or more plant-external fossil heat sources HEXT-F via ME into MH in an amount sufficient to generate heat in an amount (ΔE−EH2P) in MH;
• (c.1.3.2) if ΔH≤0,
• controlling the processing unit UP, the supply means ME and optionally the supply means MR so that an amount of H2 is passed into MH via SH which is sufficient to produce ΔE in MH;
• wherein the process further comprises:
• (iv′) optionally passing SR obtained from UR through MR, obtaining a stream S′R being x volume-% of SR, with 0<x≤100;
• (v′) passing the stream SR or, if (iv) is carried out, the stream S′R into UP, obtaining SH;
• (vi′) passing the stream SH obtained from UP through ME, obtaining a stream S′H being y volume-% of SH, with 0<y≤100;
• and
• (vii′) passing the stream S′H obtained from ME as HINT into MH;
• and
• (c.2) if ΔE≤0,
• controlling the processing unit UP, the supply means ME and optionally the supply means MR so that no H2 is passed into MH via SH;
• wherein the process further comprises:
• (iv″) optionally passing SR obtained from UR through MR, obtaining a stream S′R being x volume-% of SR, with 0≤x≤100;
• (v″) passing the stream SR or, if (iv′) is carried out and x≠0, the stream S′R into UP, obtaining SH;
• (vi″) passing the stream SH, if obtained from UP, through ME, obtaining a stream S″H being 100 volume-% of SH;
• and
• (vii″) removing the stream S″H from ME.