7.1. A plant has two process hot streams (H₁ and H₂), two process cold streams (C1 and C2), a heating util- ity (HU), and a cooling utility (CU₁). The problem data are given in Table 7.7. A value of A7min 10°F is used. Using graphical and algebraic techniques, determine the minimum heating and cooling requirements for the problem. Also, develop an HEN implementation matching the hot and the cold streams to achieve the minimum utility targets. TABLE 7-7 Stream Data for Problem 7.1 Flow Rate X Supply Target Specific Heat Temperature Temperature Stream (Btu/hr °F) (°F) (°F) Enthalpy Change (103 Btu/hr) H₁ 1000 250 120 H₂ 4000 200 100 -130 -400 HU P 280 250 C₁ 3000 90 150 180 C₂ 6000 130 190 360 CU₁ 60 80 Source: Douglas (1988).