NOVELTY - System for pyrolysis of biomass, comprises a reactor comprising at least one retort extending through it, the retorts comprises a conveyor, an inlet, and an outlet; a heating system adapted to heat the reactor; a syn-gas management system; and a controller in communication with the thermosensor and the valve. The controller switches the valve from the first position to the second position upon receiving a signal from the thermosensor that the temperature in the reactor is above a predetermined value.    USE - The system or method is useful for pyrolysis of biomass; and for converting biomass to biochar (all claimed).    ADVANTAGE - Relatively inexpensive, transportable and/or modular pyrolysis system is provided for producing biochar. The system may be simple, robust and/or flexible enough to handle a variety of locations, feedstocks and conditions.    DETAILED DESCRIPTION - System for pyrolysis of biomass, comprises a reactor comprising at least one retort extending through it, the retorts comprises a conveyor, an inlet, and an outlet; the reactor further comprises at least one thermosensor, the thermosensor capable of generating a signal when the temperature is above a predetermined value; a heating system adapted to heat the reactor; a syn-gas management system; the management system comprises a syn-gas storage tank having an inlet and an outlet, the inlet in fluid communication with the reactor, and the outlet in fluid communication with the heating system and a syn-gas outlet where the communication is controlled via a valve configurable between a first position where flow is directed to the heating system and a second position where flow is directed to the flare pipe; and a controller in communication with the thermosensor and the valve, where the controller switches the valve from the first position to the second position upon receiving a signal from the thermosensor that the temperature in the reactor is above a predetermined value; or system for pyrolysis of biomass, comprises a reactor having a retort extending through it, the retort comprising a conveyor, an inlet, and an outlet; the reactor further comprises at least one thermosensor, the thermosensor capable of generating a signal when the temperature is below a predetermined value; a heating system adapted to heat the reactor; a syn-gas management system; the management system comprising a syn-gas storage tank having an inlet and an outlet, the inlet in fluid communication with the reactor, and the outlet in fluid communication with the heating system and a syn-gas outlet where the communication is controlled via a valve configurable between at least a first position where flow is directed to the heating system and a second position where flow is directed to the flare pipe; and a controller in communication with the thermosensor and the valve; where the controller switches the valve from the second position to the first position upon receiving a signal from the thermosensor that the temperature in the reactor is below a predetermined value. INDEPENDENT CLAIMS are included for:    (1) a method for converting biomass to biochar, which involves introducing biomass to an interior of a retort in a reactor, the heated reactor; advancing the biomass through the retort by a retort conveyor extending through it, the temperature of the retort being elevated to a point where pyrolysis of the biomass occurs; collecting biochar from the retort; and applying an additive to the biochar; and    (2) a modular pyrolysis apparatus, comprising a reactor module comprising at least one retort comprising a conveyor, an inlet, and an outlet; at least one thermosensor; and a heating system adapted to heat the reactor; a syn-gas management module comprising a syn-gas storage tank, and a valve configurable between at least a first and a second position; a control module comprising a controller adapted to communicate with the thermosensor and the valve.