An overview of high pressure processes for producing chemicals from lignocellulosic biomass is presented. Special attention is given to the combination of different process steps and scale-up possibilities for the apparatus involved. Based on literature and own experiments it is shown that, under the condition of an adapted choice of process parameters, high pressure biorefinery allows the connection and combination of different high efficient and selective unit operations to a single one-stop process that can be realized in different scales. Such reactor design can be used for numerous lab scale experiments providing a basis for comparable data for different types of solid biomass. The advantage of such a screening unit is the possibility of cascading processes in the same extraction vessel. Thus, the knowledge on a convergent behavior of reaction and extraction rates can be gained, allowing to progress in modeling of solid biomass conversion under high pressure.