Steam Turbine and Steam Generator System and Operation Thereof

1 . A steam turbine system comprising fluidly in series:

at least one high pressure turbine; and/or

at least one intermediate pressure turbine; and

at least one low pressure turbine;

and further comprising steam outlet means to enable extraction of auxiliary process steam from a location upstream of the low pressure turbine; and

at least one flow restrictor in a steam extraction conduit from the or each low pressure turbine.

2 . A steam turbine system in accordance with claim 1 wherein the steam outlet means are located to enable extraction of auxiliary process steam from a location between at least one low pressure turbine and a higher pressure turbine upstream thereof.

3 . A steam turbine system in accordance with claim 2 comprising at least one high pressure turbine and at least one intermediate pressure turbine and at least ore low pressure turbine wherein the steam outlet means are located to enable extraction of auxiliary process steam from a location between at least one low pressure turbine and at least one intermediate pressure turbine.

4 . A steam turbine stem in accordance with claim 3 wherein the steam outlet means are located to enable extraction of auxiliary process steam from a location in the vicinity of the IP/LP crossover.

5 . A steam turbine system in accordance with any claim 1 wherein the steam turbine system further comprises one or more fluid conduits fluidly continuous with the steam outlet means to convey auxiliary process steam to additional process module(s) as a source of motive power and/or latent heat.

6 . A steam turbine system in accordance with claim 5 comprising fluid conduit fluidly continuous with the steam outlet means to convey auxiliary process steam to an associated post combustion carbon capture plant.

7 . A steam turbine system in accordance with 1 claim comprising a generator for generation of steam from combustion of carbonaceous fuel, and adapted for use with an associated means for post-combustion carbon capture.

8 . A steam generator system with post-combustion carbon capture capability comprising:

a steam generator to produce steam from combustion of carbonaceous fuel;

a steam turbine system in accordance with any preceding, claim;

a post-combustion carbon capture apparatus fluidly disposed to recover CO 2 from combustion gases generated by the combustion of carbonaceous fuel in use;

a fluid conduit fluidly continuous with the steam outlet means to convey auxiliary process steam to the post-combustion carbon capture apparatus.

9 . A system in accordance with claim 8 wherein the post-combustion carbon capture system comprises an absorber column where CO 2 is separated from the flue gas by means of absorption by passing the gas through a column where the as flows in an opposite direction to an absorbent in liquid phase.

10 . A system in accordance with claim 8 wherein the post-combustion carbon capture system further comprises a regeneration column where CO 2 is removed from absorbent by regenerative heating.

11 . A system in accordance with claim 10 comprising a condenser redder is disposed to receive absorbent solution and reboil the solution to regenerate lean absorbent.

12 . A system in accordance with claim 1 wherein the flow restrictor is a valve.

13 . A system in accordance with claim 12 wherein the flow restrictor is selected from: a control valve, a globe valve with a suitably shaped and actuated plug, a butterfly valve with a suitably shaped and actuated disk, a non-return valve with a suitably shaped and actuated restriction.

14 . A method of modification of a steam generator comprising

at least one high pressure turbine and/or at least one intermediate pressure turbine and at least one low pressure turbine;

the method comprising the step of:

incorporating a flow restrictor into a steam extraction conduit of the or each low pressure turbine to allow the variation of mass flows therefrom by suitable modification of pressures.

15 . A method of modification of a steam generator in accordance with claim 14 comprising the additional step of:

providing steam outlet means to enable extraction of auxiliary process steam from a location upstream of the low pressure turbine, for example to supply a post combustion carbon capture plant with a source of motive power and/or latent heat.

16 . The method of claim 14 performed as a method of after-market modification of existing plant in situ.

17 . A method of operation of a steam turbine system having at least one high pressure turbine and/or at least one intermediate pressure turbine and at least one low pressure turbine comprising:

drawing auxiliary process steam from a location upstream of the low pressure turbine;

modifying the flow of steam extracted downstream of the low pressure turbine to move the flow regime from the LP turbine towards a more desired location on a notional Exhaust Loss Curve.

18 . The method of claim 17 wherein the step of modifying the flow of steam extracted downstream of the low pressure turbine is performed dynamically and simultaneously with the step of drawing auxiliary process steam to promote stability of operation by moving the flow regime of LP Turbine right along the Exhaust Loss Curve.

19 . The method of claim 18 wherein the step of modifying the flow of steam extracted downstream of the low pressure turbine is performed by operation of a suitable flow restrictor such as a control valve in the LP turbine steam extraction conduit.

20 . The method of claim 14 wherein the steam generator comprises at least one high pressure turbine and at least one intermediate pressure turbine and at least one low pressure turbine, and the method comprises drawing off auxiliary process steam from a location between the at least one intermediate pressure turbine and the at least one low pressure turbine.