Improvement of pinch technology for the possibility of integration of non-stationary thermal processes, taken into account of their localization

Abstract

RELEVANCE.  Designing  a  network  of  heat  exchangers  for  heat  recovery  and integration  of  thermal  processes  in  general  is  a  very  urgent  task  of  energy  saving.  Such  a powerful and  widely  used  tool  for  the  synthesis  and design of a network of  heat exchangers  as pinch  technology  has  a  number  of  limitations,  and  this  study  is  aimed  at  expanding  its capabilities. Pinch technology can only work effectively with stationary heat flows. In practice, cyclic  and  periodic  processes  are  encountered,  which  limits  the  possibilities  of  using  pinch technology.  This  was  the  reason  for  this  study  with  the  aim of  expanding  the  boundaries  of application  of  pinch  technology.  THE  PURPOSE.  Improving  the  pinch  technology  method  to expand the possibilities for integrating cyclic and periodic thermal processes, as well as taking into  account  their  localization.  METHODS.  When  solving  the  problem,  the  principle  of determining heat exchange connections was analyzed, other algorithms for their selection were proposed,  and  new  optimization  criteria  were  synthesized.  RESULTS.  A  criterion  for  the structural  perfection  of  a  system  is  proposed,  which  is  the  ratio  of  the  heat  regenerated  in  the system  to  its  theoretically  possible  value.  The  theoretical  results  are  the  proposed  criterion  of structural  perfection and  a  generalized  indicator  of  the  structural-parametric  perfection of  the system.  The  practical  result  of  the  study  was  the  proposed  technical  device  for  converting  an unsteady  flow  into  a  series  of  stationary  flows.  Also,  the  practical  result  of  this  scientific research  is  a  program  for  the  synthesis  of  heat  exchange  networks.  The  proposed  conversion device  expands  the  capabilities  of  pinch  technology,  and  the  introduced  criteria  will  make  it possible to synthesize or design a system based on new target indicators. The program created during  the  work  allows  for  the  synthesis  of  a  heat  exchange  network  in  automatic  and  semi-automatic  modes.  CONCLUSION.  Thanks  to  the  research  carried  out,  it  was  possible  to improve  such a  powerful  tool  as  pinch  technology and  significantly expand  its  capabilities.  An improvement of pinch technology has been proposed to enable the integration of non-stationary thermal  processes  and  take  into  account  their  localization.  To  enable  the  integration  of  non-stationary  thermal  processes,  a  technical  device  has  been  proposed  that  allows  converting  a non-stationary  flow  into  several  stationary  ones,  and  to  take  into  account  the  localization  of heat  flows,  a  software  product  has  been  proposed  that  allows  for  the  synthesis  of  a  heat exchange  network  in  automatic  and  semi-automatic  modes.  In  addition,  two indicators  have been  introduced  that  characterize  the  structural  and  structural-parametric  perfection  of  the system.