A perfectly-stirred reactor (PSR) model based on the hybrid Newton/time integration methodology (Grcar et al., 1988) is developed and coupled to two state-of-the-art soot moment techniques, namely the method of moments with interpolative closure (MOMIC) and the hybrid method of moments (HMOM), with the latter coupling being implemented for the first time for investigating soot formation and growth. Five different PSR calculations based on initial data from previous simulations and experiments are carried out in the present study at various equivalence ratios, temperatures, and residence times, in order to test this coupling. These calculations consist of combustion of mixtures of ethylene, ethylene-benzene blends, methane, and acetylene, with air. The PSR algorithm employs a procedure of switching between steady-state and pseudo-transient calculations of the nonlinear algebraic steady PSR equations in order to achieve a more conditioned estimate of the initial guess. Soot moment equations are coupled with species conservation equations to obtain soot quantities, such as soot volume fraction, particle number density, particle diameter, and soot surface area density. As expected, soot volume fraction, particle number density, and soot surface area density all increased with an increase in fuel-air equivalence ratio, (), and residence time, where HMOM mostly predicted lower values of these quantities than MOMIC. The particle diameter variations with were case-specific, but HMOM always predicted larger-sized soot particles than MOMIC. Comparisons with experimental data, where available, showed that both HMOM and MOMIC overpredicted the soot volume fraction.