Steam generation apparatus and method

Abstract

In one aspect, the invention provides a steam generation apparatus that is liquid fuel fired and addresses conversion of gaseous fuel SIB units to operate with liquid fuel. The invention also relates to a conversion unit for a steam injection boiler, a method for converting a steam injection boiler from gas firing to possible liquid fuel firing and a method for generating steam from a liquid fuel source. The invention employs a fired heater for heating the liquid fuel to a temperature suitable for firing and preheats the water to compensate for the shortfall in beat liberation when a gas boiler is converted to use liquid fuel. In another aspect of the invention, production of steam is achievable consistently by employing step-up heaters with a steam injection boiler. The heaters being connected in parallel to continue heating the water/steam to achieve a higher quality steam over that produced in the boiler while minimizing consideration as to the adverse effects of coil fouling in the boiler.

1 - 35 . (canceled)  
   
   
       36 . A steam generation apparatus comprising: 
 a steam injection boiler including a combustion chamber and a water tube circuit extending through the steam injection boiler combustion chamber, the water tube circuit selected to convey water in order to heat the water to generate steam;    a step-up heater to accept steam from the steam injection boiler and being operable at conditions to heat the steam from the steam injection boiler to a level wherein fouling of water solids occurs in the step-up heater preferentially over fouling occurring in the steam injection boiler.    
   
   
       37 . The steam generation apparatus of  claim 36  wherein the step-up heater is selected to generate steam with a quality greater than 80%.  
   
   
       38 . The steam generation apparatus of  claim 36  wherein the step-up heater includes controls for adjustment of temperature and/or pressure therein to cause fouling of water solids.  
   
   
       39 . The steam generation apparatus of  claim 36  wherein the steam injection boiler uses combustion of gaseous and/or liquid fuel to generate steam.  
   
   
       40 . The steam generation apparatus of  claim 36  wherein the step-up heater uses combustion of gaseous and/or liquid fuel to heat the steam.  
   
   
       41 . The steam generation apparatus of  claim 36  further comprising a flow control actuable to prevent passage of steam from the steam injection boiler to the step-up heater.  
   
   
       42 . A steam generation apparatus for connection to a steam injection boiler including a water tube circuit extending through the steam injection boiler and selected to convey water in order that the water is heated to generate steam, the steam generation apparatus comprising: 
 a first step-up heater connectable in fluid communication with the boiler water tube circuit; and    a second step-up heater in fluid connectable communication with the boiler water tube circuit,    the first and second step-up heaters being operable at conditions to treat the water in association with the boiler to a level wherein fouling of water solids occurs in the first step-up heater and the second step-up heater preferentially over fouling occurring in the boiler and the first and second step-up heaters being connected in parallel such that one step-up heater can be operated while the other step-up heater is offline.    
   
   
       43 . The steam generation apparatus of  claim 42  wherein the first step-up heater is selected to operate with the steam injection boiler to generate steam with a quality greater than 80%.  
   
   
       44 . The steam generation apparatus of  claim 42  further comprising a control for adjustment of temperature and/or pressure in the first step-up heater to cause fouling of water solids.  
   
   
       45 . The steam generation apparatus of  claim 42  wherein the first step-up heater and the second step-up heater use combustion of gaseous and/or liquid fuel to heat the steam.  
   
   
       46 . The steam generation apparatus of  claim 42  wherein the first step-up heater and the second step-up heater are positioned up stream of the steam injection boiler.  
   
   
       47 . The steam generation apparatus of  claim 42  wherein the first step-up heater and the second step-up heater are positioned to receive steam generated in the steam injection boiler.  
   
   
       48 . The steam generation apparatus of  claim 42  further comprising a flow control actuable to select whether the water in association with the steam injection boiler is passed to the first step-up heater, to the second step-up heater or to both the first step-up heater and the second step-up heater.  
   
   
       49 . A steam generation apparatus comprising: 
 a steam injection boiler including a burner operable therein and a boiler water coil extending through the steam injection boiler and including an outlet the boiler water coil selected to convey water in order to heat the water to generate steam;    at least a first heater and a second heater, each including a steam heating circuit, the steam heating circuits being connected in parallel with each other and in fluid flow communication with the boiler water coil and the heater selected to increase the steam quality of the steam passing from the steam injection boiler; and    a flow controller to control flow through the first and the second heaters and actuable to select that flow is permitted through only a selected one of the first heater steam heating circuit and the second heater steam heating circuit.    
   
   
       50 . The steam generation apparatus of  claim 49  wherein the flow controller is further actuable to select that flow is permitted through both the first heater steam heating circuit and the second heater steam heating circuit simultaneously.  
   
   
       51 . The steam generation apparatus of  claim 49  wherein the first heater is selected to generate steam with a quality greater than 80%.  
   
   
       52 . The steam generation apparatus of  claim 49  further comprising a control for adjustment of temperature and/or pressure in the first heater to cause fouling of water solids in the steam heating circuit therein.  
   
   
       53 . The steam generation apparatus of  claim 49  wherein the steam injection boiler uses combustion of gaseous and/or liquid fuel to generate steam.  
   
   
       54 . The steam generation apparatus of  claim 49  wherein the first heater uses combustion of gaseous and/or liquid fuel to heat the steam.  
   
   
       55 . The steam generation apparatus of  claim 49  wherein the first heater and the second heater are positioned to receive steam generated in the steam injection boiler.  
   
   
       56 . The steam generation apparatus of  claim 49  further comprising ducts to combine any combustion gases generated from the first heater and the second heater.  
   
   
       57 . The steam generation apparatus of  claim 49  further comprising ducts to combine any combustion gases generated from the first heater and the steam injection boiler.  
   
   
       58 . A method for generating steam, the method comprising: 
 providing a steam generation apparatus including a fired steam injection boiler including a combustion chamber and a water tube extending through the steam injection boiler combustion chamber;    providing a step-up heater in series after the steam injection boiler including a steam/water tube extending therethrough;    operating the steam injection boiler to convey water through the water tube to heat the water to generate steam;    operating the step-up heater to receive steam generated in the steam injection boiler and passing it through the steam/water tube at conditions to heat the steam from the boiler to a level wherein fouling of water solids occurs in the step-up heater preferentially over fouling occurring in the steam injection boiler.    
   
   
       59 . The method of  claim 58  wherein operating the step-up heater generates steam with a quality greater than 80%.  
   
   
       60 . The method of  claim 58  wherein operating the step-up boiler includes adjusting the temperature and/or pressure therein to cause fouling of water solids.  
   
   
       61 . The method of  claim 58  wherein operating the steam injection boiler includes combusting gaseous and/or liquid fuel.  
   
   
       62 . The method of  claim 58  wherein operating the step-up boiler includes combusting gaseous and/or liquid fuel.  
   
   
       63 . A method for generating steam, the method comprising: 
 providing a steam generation apparatus including a fired steam injection boiler including a combustion chamber and a water tube extending through the steam injection boiler combustion chamber;    providing a first step-up heater and a second step-up heater;    operating the boiler to convey water through the water tube to heat the water to generate steam;    operating at least the first step-up heater at conditions to heat the water in association with the boiler to a level wherein fouling of water solids occurs in the first step-up heater preferentially over fouling occurring in the steam injection boiler;    shutting down the first step-up heater to defoul it; and    operating the second step-up heater to heat the water in association with the boiler while the first step-up heater is shut down.    
   
   
       64 . The method of  claim 63  wherein operating the first step-up heater generates steam with a quality greater than 80%.  
   
   
       65 . The method of  claim 63  wherein operating the first step-up heater and/or the second step-up heater includes adjusting the temperature and/or pressure therein to cause fouling of water solids.  
   
   
       66 . The method of  claim 63  wherein operating the steam injection boiler includes combusting gaseous and/or liquid fuel.  
   
   
       67 . The method of  claim 63  wherein operating the step-up heater includes combusting gaseous and/or liquid fuel.  
   
   
       68 . The method of  claim 63  wherein the first step-up heater and the second step-up heater are operated simultaneously.  
   
   
       69 . The method of  claim 63  further comprising chemically defouling the first step-up heater during shut down.  
   
   
       70 . A method for generating steam comprising: 
 using a steam injection boiler including a burner operable therein and a boiler water coil extending through the steam injection boiler and including an outlet of the boiler water coil, the steam injection boiler selected to convey water in order to heat the water to generate steam; at least a first heater and a second heater, each including a steam heating circuit, the steam heating circuits being connected in parallel with each other and in fluid flow communication with the boiler water coil and selected to increase the steam quality of the steam passing from the steam injection boiler; and a flow controller to control flow through the first and the second heaters;    conveying water through the boiler water coil and through the steam heating circuit of a selected one of the first heater or the second heater to generate steam from the water;    defouling the steam heating circuit of the other of the first heater or the second heater; and    switching flow to the other of the first heater or the second heater when the steam heating circuit of the selected heater when it is desired to defoul the steam heating circuit of the selected one of the first heater or the second heater.    
   
   
       71 . The method of  claim 70  wherein the steam heating circuit of the first heater generates steam of greater than 80% quality.  
   
   
       72 . The method of  claim 70  further comprising conveying water through the first heater and the second heater simultaneously to generate steam.  
   
   
       73 . The method of  claim 70  wherein defouling includes chemically defouling.